Next Article in Journal
Improving the Performance of Hydrological Model Parameter Uncertainty Analysis Using a Constrained Multi-Objective Intelligent Optimization Algorithm
Next Article in Special Issue
Eco-Engineering Technologies and Achievements of Projects for Reconstructing Landscape Water from Aquaculture Ponds in Shanghai
Previous Article in Journal
Determination of Flash Flood Hazard Areas in the Likodra Watershed
Previous Article in Special Issue
Perovskite LaMnO3 Composite Graphene Carbon Nitride g-C3N4 Improves the Photocatalytic Performance of Tetracycline Degradation
 
 
Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 
Journals
Water
Volume 15
Issue 15
10.3390/w15152699
water-logo
Submit to this Journal Review for this Journal Propose a Special Issue
► Article Menu

Article Menu

share Share announcement Help format_quote Cite question_answer Discuss in SciProfiles thumb_up
...
Endorse textsms
...
Comment
first_page
settings
Order Article Reprints
Font Type:
Arial Georgia Verdana
Font Size:
Aa Aa Aa
Line Spacing:
Column Width:
Background:
Article

A Study on Nitrogen and Phosphorus Budgets in a Polyculture System of Oreochromis niloticus, Aristichthys nobilis, and Cherax quadricarinatus

by
Banghui Liu
1,2,
Kai Zhang
3,
Guangjun Wang
3 and
Xugang He
1,4,5,*
1
College of Fisheries, Huazhong Agricultural Univesity, Wuhan 430070, China
2
School of Ocean and Fisheries, Guangdong Eco-Engineering Polytechnic, Guangzhou 510320, China
3
Pearl River Fisheries Research Institute, Guangzhou 510380, China
4
Freshwater Aquaculture Collaborative Innovation Center of Hubei Province, Wuhan 430070, China
5
Key Laboratory of Aquaculture Facilities Engineering, Ministry of Agriculture and Rural Affairs, Wuhan 430070, China
*
Author to whom correspondence should be addressed.
Water 2023, 15(15), 2699; https://doi.org/10.3390/w15152699
Submission received: 22 June 2023 / Revised: 17 July 2023 / Accepted: 24 July 2023 / Published: 26 July 2023
(This article belongs to the Special Issue Aquaculture Water Safety)
Browse Figure
Versions Notes

Abstract

:
Polyculture is an effective way to achieve efficient utilization of nutrient resources in high-density intensive aquaculture systems. In order to study the optimal culture mode of Oreochromis niloticu, Aristichthys nobilis, and Cherax quadricarinatus, the budget of nitrogen and phosphorus in various polyculture systems (CH, CHC1, CHC2, CHC3) was studied with land-based enclosures. The results showed that all the three polyculture systems had higher total yields of cultured animals than the control group (two polyculture systems) (p < 0.05). The co-cultured organisms absorbed artificial feed or organic matter (such as plankton and sediment) from the polyculture system to different degrees. Feed was the main input of nitrogen (98.22–98.33%) and phosphorus (99.43–99.56%) in all systems. Considering the N and P outputs, 46.64–64.58% and 81.60–84.79%, respectively, accumulated in the sediment, and 34.43–52.55% and 14.89–17.30% of the N and P outputs, respectively, were harvested by aquaculture organisms. The pollution production coefficients of TN and TP in the O. niloticus polyculture ponds were 5.35–6.26 g/m2 and 1.17–1.61 g/m2, respectively. The TN production coefficients of O. niloticus and the ternary polyculture groups (CHC1, CHC2, and CHC3) were lower than that of the control group (CH). The TP production coefficients showed the opposite pattern. The N and P utilization efficiencies in the group with the optimal ratio of O. niloticus, A. nobilis, and C. quadricarinatus (4, 0.15, and 3 ind/m2, respectively) were 2.56–12.82% and 6.62–11.03% higher, respectively, compared with those of the other groups. The N utilization efficiency was effectively improved in this group with the optimum stocking density for the polyculture systems, resulting in improved ecological efficiency and economic benefits.

1. Introduction

Oreochromis niloticus is the most common commercially farmed fish species worldwide; it is characterized by fast growth, easy domestication, and tolerance to transportation [1]. It is also a major farmed species in China, particularly in south China. O. niloticus aquaculture is expanding yearly: the stocking density is increasing, and greater amounts of feeds and fertilizers are being applied in response to the ever-increasing market demand. This increases the N and P contents in the water body, exacerbates eutrophication, and causes frequent diseases, with decreasing yields. These issues affect the sustainable development of intensive O. niloticus aquaculture [2].
Polyculture is a production method wherein different aquaculture organisms are proportionally cultured within the same system based on the principles of ecological balance, mutually beneficial species relationships, and multi-nutrient utilization [3]. Polyculture improves ecological stability and nutrient recycling, which may result in synergistic benefits to the participating species. In aquaculture, this synergism can result in increased profitability through improved growth rates and/or reduced feed inputs [4]. Integrated aquaculture may improve the resource utilization efficiency in aquaculture systems, reduce environmental pollution, increase the biodiversity and yields of aquaculture organisms, and decrease the incidence of diseases [5,6]. In traditional Chinese pond culture, pond nesting is the main mode of A. nobilis culture in Guangdong and even the whole of China. The first purpose of pond nesting is to improve the added value of the main fish culture. The second is to share a certain proportion of pond rent, electricity and other breeding costs, or to make more profit from nesting A. nobilis [7]. Third, bighead carp exhibit filter-feeding behavior, consuming particulate matter and plankton in the aquatic environment. This behavior promotes relative stability and balance among plankton in the water column, thereby effectively controlling water blooms caused by eutrophication [8]. In the Guangdong area, grass carp, tilapia, white shrimp and some other intensive culture ponds all contain A. nobilis, and the stocking density is mostly 750~3000 ind/hm2 [7]. At the same time, our previous experiments showed that the co-culture of O. niloticus + A. nobilis (biomass ratio = 15~25:1) + shrimps (Macrobrachium rosenbergii, Penaeus vannamei and Metapenaeus ensis) could significantly improve the economic benefits of O. niloticus [9]. Hence, this paper established the biomass ratio in reference to the above studies. Since their introduction to China in 1992, C. quadricarinatus have been utilized in polyculture models due to their diverse feeding habits, including consuming bottom-dwelling organisms, algae, and detritus [10,11,12]. Polycultures of tilapia and C. quadricarinatus can efficiently utilize resources, improving culture efficiency, regulating water quality, and reducing pollution through their diurnal cross-activities, ecological niches, and feeding composition [13,14,15]. The polyculture of these three species is a new farming model for adding value and decreasing pollutant emissions in China, as they have relatively good complementary feeding habits and growth space [9,16]. However, the stocking density and ratio of the three species lack relevant norms and theoretical guidance and are mostly determined based on experience during actual production. Therefore, studying N and P budgets in O. niloticus, A. nobilis, and C. quadricarinatus polyculture systems and comparing differences in environmental parameters between different polyculture models can provide data to support the optimization of polyculture models and improve the related aquaculture management.
Nitrogen and P are generally the limiting nutrient elements in aquaculture, and their levels can directly reflect changes in the aquaculture environment [17]. Nitrogen and P budgets (and their utilization efficiencies) can be used to quantify the pollution level in an aquaculture system to evaluate its strengths and weaknesses [18]. The N and P budget in aquaculture systems is widely studied, including in channel catfish (Ictalurus punctatus) ponds in America [19], intensive fishponds of gilthead seabream (Sparus aurata) in Israel [20], shrimp (Penaeus monodon) culture ponds [18], Litopenaeus vannamei and Portunus trituberculatus culture ponds [21], scampi (Macrobrachium rosenbergii) culture ponds [22] in India, crab culture ponds [23], and polyculture culture ponds of snakehead [24]. Relevant domestic and foreign research about O. niloticus has mainly focused on the N and P budgets of O. niloticus—fish polyculture, prawn—O. niloticus polyculture, and O. niloticus monoculture ponds [25,26,27,28,29], and there are few reports on N and P budgets of O. niloticus—A. nobilis polyculture systems. Therefore, this study established a series of farming models with different polyculture ratios based on the different growth spaces and feeding habits of the three freshwater aquaculture organisms. Land-based enclosure experiments were used to study the N and P budgets of four different polyculture systems of O. niloticus, A. nobilis, and C. quadricarinatus. We compared N and P accumulation in the sediments and water under different culture models and the utilization rates of N and P in each system. Together, we hope to provide a theoretical basis to optimize polyculture systems based on O. niloticus.

2. Materials and Methods

2.1. Experimental Ponds and Materials

This study was conducted at the aquaculture base of Zhuhai Deyang Aquaculture Co., Ltd., located in Zhuhai, Guangdong, China, from 12 May 2020 to 12 November 2020, and completed within 184 days.
The experiments were conducted using enclosure ecosystems in a freshwater pond with an area of approximately 1 ha that had a sediment bottom and a water depth of 1.8 to 2.0 m during the experiment. Twelve small ponds which were divided into four groups with three replicates per group were created with a 2 m distance from the edge of the freshwater pond as land-based experimental enclosures. The enclosures were constructed using impervious polyvinyl plastics and supported with timber piles. The area of each enclosure was 64 m2 (8 m × 8 m). Separation of the pond area by enclosures avoided water exchanges among different experimental systems. The specific structure of the enclosure was previously reported in Deshang [30].
The O. niloticus, A. nobilis, and C. quadricarinatus individuals used in the experiment were sourced from Zhuhai Deyang Aquaculture Co., Ltd. (Zhuhai, China), and their mean stocking sizes were 6.2 ± 0.44, 20 ± 1.56, and 1.25 ± 0.09 g, respectively (Table 1). Four treatments were established, with three replicates of each treatment based on the species and densities of the experimental animals in the small ponds. There were three test treatments (CHC1, CHC2, and CHC3) and one control treatment (CH). The composition and stocking density of each treatment are shown in Table 1.

2.2. Aquaculture Management

O. niloticus was fed with a commercial pellet feed manufactured by Guangdong Haid Group Co., Ltd. (Guangzhou, Guangdong, China), and the feed amount was equivalent to 5% of body mass. The feed intake was observed daily, and the feed amount was adjusted based on the weather conditions, water temperature, and fish growth. An aeration tray was placed in each small enclosure pond to ensure that the dissolved oxygen was greater than 5 mg/L in the water. The water was not replaced during the experiment; however, the water lost owing to evaporation, filtration, and sampling was replenished as needed. Harvesting conditions were determined using a previously reported method [24].

2.3. Response Variables and Analytical Methods

2.3.1. Determination of Dissolved Oxygen, pH Value, and Temperature of Pond Water

The dissolved oxygen content was measured once every 15 days with a HACH LDO™ portable dissolved oxygen tester, and the pH value and temperature (°C) were measured with an HI9813-6 pH-EC-TDS-°C.

2.3.2. Measurement of Nutrients of Pond Water Samples and Interstitial Water

One liter of water (including suspended solids and phytoplankton) was collected from the upper, middle, and lower water layers at the four corners and center of each small pond before, during, and after the experiment using a water sampler (Rong Sheng, China) every 15 days. The depths of the sites where water samples were collected was 0.5 m. Ten-centimeter-thick sediment was collected using a mud collector at the bottom of the pond and centrifuged for 10 min at 8000 r/min. Then, the interstitial water was collected, and the seepage of N and P was calculated according to the concentration of interstitial water. The water samples of each group were mixed prior to determining the total ammonia nitrogen (TAN), nitrite (NO2−-N), nitrate (NO3−-N), active phosphate (PO43−-P), total nitrogen (TN), and total phosphorus (TP) contents according to previously reported methods [31,32].

2.3.3. Collection and Measurement of Breeding Organisms, Sediment, and Feed

Biological samples were collected before and after stocking the organisms. TN and TP were also collected and their contents determined using the above methods. At the same time, prior to stocking with aquaculture species, three sediment collection tubes were placed in each small pond, with the openings 1.0 m below the water surface. A cylindrical polyvinyl chloride (PVC) tube (diameter and height: 90 and 550 mm, respectively) was used to collect sediment, and the tubes’ openings were covered with a nylon net (mesh 2a = 0.8 cm) to prevent aquaculture organisms from entering. At the end of the experiment, the sediment collection tubes were removed, the upper layer of water was siphoned out, and the sediment height (containing settled phytoplankton) was measured. Then, the sediment was poured into a large culture dish (15 cm), oven-dried at 60 °C for 48 h, crushed, and sieved using a 100-mesh screen. The TN content was determined using an elemental analyzer (Elementar III, Varian, Germany), and the TP content was determined using the acid-soluble molybdenum–antimony anti-colorimetric method [33]. The stocked animals, feed, and the harvested animals were dried at 60 °C to a constant weight, smashed, and sieved with a sample sifter (0.15 mm pore size). The TN of these samples was determined using a Vario ELIII Elemental Analyzer (Elementar, Dortmund, Germany). The TP levels of the stocked animals, feed, and harvested animals were determined using the molybdenum yellow spectrophotometer method [34].

2.3.4. Determination of the Growth Parameters of Breeding Organisms

The feeding situation of breeding organisms was observed every day. The amount of bait cast and death rates were recorded in detail, and the weight of raised organisms was measured at the end of breeding. Three samples were obtained from each experimental enclosure every 5 days, and their growth was recorded.

2.3.5. Determination of Other Indicators

In the period before and after the breeding cycle, the enclosures were analyzed to assess nutrient absorption, and the nutrient content (also known as adsorption amount) was calculated. Rainwater was collected outdoors, and the inputs of N and P from rainwater were determined by estimating their amounts in rainfall.

2.3.6. Calculation Formula

Nitrogen and P budgets and the system N and P utilization rate were calculated as previously described [24] for the harvest of breeding organisms. The N and P pollution production coefficients of the aquaculture ponds were estimated [35] according to the material scale algorithm, and the pollution production coefficient of N and P in the sediment was calculated according to the area method [36].

2.4. Statistical Analysis of Data

The data are presented as the mean and standard deviation (mean ± SD). The data were analyzed using one-way analysis of variance (ANOVA) by LSD multiple comparison tests using the computer software of SPSS 21.0, to determine whether there were significant differences between all the four systems. Cases with p < 0.05 were considered statistically significant.

3. Results

3.1. Environmental Parameters

The initial environmental parameters did not differ between the treatment groups (p > 0.05) (Table 2). The environmental levels of TN and TP in the sediment were 0.74–0.793 g/L and 0.617–0.683 g/L respectively. The variation in water environmental parameters is shown in Table 2. The temperature fluctuation was 23.5–33.4 °C, the dissolved oxygen contents and pH were in the range of 4.83–13.1 mg/L and 7.07–8.39, respectively, and the TAN, NO3−-N, NO2−-N, TN, PO43−-P, and TP contents were 0.024–1.49, 0.019–1.46, 0.002–0.171, 0.504–2.23, 0.005–0.219, and 0.009–0.254 mg/L, respectively.

3.2. Harvesting Conditions

Table 3 shows that feeds and feed coefficients of O. niloticus were similar between the treatment groups at the time of harvesting (p > 0.05). In CHC2, the average body weight was 0.684 ± 0.009 kg/ind, the survival rate was 93.2 ± 2.16%, and the yield was 25.5 ± 0.803 Ton/hm2. These data were noticeably higher than those in CH (p < 0.05), but not significantly different from those in CHC1 and CHC3 (p > 0.05). The survival rate of A. nobilis in all groups was 100%, and the size and yield did not differ (p > 0.05). The size of C. quadricarinatus did not differ between the treatment groups at the time of harvesting (p > 0.05). The survival rates in CHC1 and CHC2 were greater than that in CHC3 (p < 0.05), and the yield in CHC2 was higher than those in CHC1 and CHC3 (p < 0.05). There was no significant difference in total aquaculture output between the CHC2 and CHC3 groups (p > 0.05), but it was significantly higher than that of CH and CHC1 groups (p < 0.05).

3.3. Dry Matter and Nitrogen and Phosphorus Contents of Feed and Breeding Organisms

The feed and O. niloticus, A. nobilis, and C. quadricarinatus stocking dry matter and nitrogen and phosphorus contents in Table 4 show that harvest experimental biological dry matter and N and P contents have different degrees of increase (p < 0.05) compared with those of stocked organisms. This shows that grazing organisms absorbed artificial feed or organic matter (such as plankton and sediment) from the breeding system to different degrees.

3.4. Contents of Dry Matter, N, and P, and Densities in the Sediment of Different Enclosures before and after the Experiment

The moisture content of the sediment significantly increased (p < 0.05), and the density decreased (p < 0.05) after the experiment (Table 5). Furthermore, the N and P contents in the sediment accumulated to a large extent (p > 0.05).

3.5. N and P Inputs

The N and P were primarily derived from the feed in all treatment groups. The inputs were 203.6–211.7 g/m2 and 46.7–47.02 g/m2, respectively, constituting 98.2–98.3% and 99.4–99.6% of the N and P inputs into the system, respectively (Table 6). The inputs of N and P from the initial water body were 1.98–2.12 g/m2 and 0.13–0.18 g/m2, respectively, accounting for 0.93–1.02% and 0.28–0.39% of the N and P inputs of the system, respectively. The stocked organisms and rainfall marginally contributed to the N and P inputs in all treatment groups.

3.6. N and P Outputs

The primary N output was sediment deposition. The output of N to sediment was 65.6–121.4 g/m2, which constituted 55.2–65.6% of the N output of the system in all treatment groups (Table 7). The secondary N output was the harvested aquaculture organisms. It reached 65.8–74.0 g/m2, which accounted for 33.8–52.2% of the N output in the system. The seepage was 0.34–2.51 g/m2, which accounted for 0.20–1.29% of the output of the system N and P. The output of N by ammonia volatilization and absorption and the amount of N accumulated in the water body accounted for non-significant proportions of the TN output.
The output of P to the sediment in all treatment groups was 34.9–37.0 g/m2, which constituted 81.0–83.4% of the P output of the system. The P output through the harvesting of aquaculture organisms was 6.50–7.31 g/m2, which accounted for 14.6–17.2% of the P output of the system. The seepage was 0.17–0.48 g/m2, which accounted for 0.33–1.08% of the N and P output of the system. The amount of P accumulation and absorption in the water body accounted for a non-significant proportion of the TP output.
The amount of N accumulated in the water body and sediment in CHC2 was notably lower than in other groups (p < 0.05) (Table 7). The amount of P accumulated in the water body in CHC3 was the highest among the groups (p < 0.05), yet the amounts of P accumulated in the sediment were similar for all groups (p > 0.05).

3.7. N and P Utilization Efficiencies

The N utilization efficiency of the treatment groups increased in the following order: CH (31.20%) < CHC1 (32%) < CHC3 (32.8%) < CHC2 (35.2%). The P utilization efficiency of the treatment groups increased in the following order: CH (13.6%) < CHC3 (13.6%) < CHC1 (14.5%) < CHC2 (15.1%) (Figure 1). The P utilization efficiency in CHC2 was the highest and was substantially greater than the P utilization efficiencies in CH and CHC3 (p < 0.05), and similar to that in CHC1 (p > 0.05).

3.8. Pollution Production Coefficients of the Ponds (PPCP) and Sediment Deposition (PPCSD)

The calculated TN and TP pollution production coefficients of O. niloticus farming with different treatment groups are presented in Table 8. The TN pollution coefficients of the ponds were 6.01 g/m2, 5.35 g/m2, and 5.41 g/m2 in the CHC1, CHC2, and CHC3 groups, respectively. The TN pollution coefficient in CHC1 was not significantly different from that of the CH group (p > 0.05), whereas the values in all other groups were significantly lower than the value of 6.26 g/m2 in the CH group (p < 0.05). The coefficients of TP pollution were 1.61 g/m2, 1.52 g/m2, and 1.56 g/m2 in the CHC1, CHC2, and CHC3 groups, respectively. Therefore, they were significantly higher than the 1.17 g/m2 observed in the CH group (p < 0.05). The coefficients of TN contamination in the CHC1, CHC2 and CHC3 groups were 13.5 g/m2, 12.5 g/m2 and 11.9 g/m2, respectively, and these values were significantly lower than the value of 14.75 g/m2 in the CH group (p < 0.05). There were significant differences among other groups (p < 0.05), except between CHC2 and CHC3 groups (p > 0.05). However, there was no significant difference in the TP production coefficients between the treatment groups (p > 0.05).

4. Discussion

4.1. N and P Inputs and Outputs

The common sources of N and P inputs in pond aquaculture systems are the feeds and fertilizers applied, the farmed animals, the initial water body, and rainfall [37]. Feeds and fertilizers are the major sources of N and P inputs, constituting 70–95% of the TN and P inputs in aquaculture systems [24,38]. This result was confirmed in studies of the intensive O. niloticus farming model [26] and polyculture ponds of tilapia [26,27], in which the inputs of N and P from feed constituted 84.3–92.6% and 81.9–98.7% of the N and P inputs to the system, respectively. In this study, the inputs of N and P from feed constituted 98.2–98.3% and 99.4–99.6% of the N and P inputs to the system, respectively. This indicates that the feed was the main source of N and P in the aquaculture ponds. The slightly higher levels recorded in this study compared with those recorded in previous studies may be related to differences in the initial amount of ammonia nitrogen in the water body, the lack of water exchange throughout the whole experiment, and the administration of only one type of artificial compound feed.
Previous reports indicate that N and P output by percolation can constitute 0.10–1.28% and 0.11–1.3% of the TN and P input, respectively [21,39]. In this study, the seepage outputs in relation to total output of N and P of the system were 0.2–1.29% and 0.33–1.08%, respectively. This is consistent with the results reported above. The absorption was less and had little influence on the experiment. Furthermore, studies suggest that sediment accumulation plays an integral role in the N and P outputs in aquaculture systems, with the outputs of N and P via sediment accumulation accounting for 19.4–73.4% and 39.5–93.5% of the TN and TP outputs of the system, respectively [40,41]. In this study, the outputs of N and P through sediment accumulation constituted 55.2–65.6% and 81.00–83.4% of the N and P outputs, respectively. This result is consistent with those from previous research of intensive tilapia (Oreochromis niloticus) culture ponds [26,28]. The proportions of N and P accumulated in sediment in the TN and TP outputs were considerably different. This may be related to differences in the N and P cycles. In the N cycle, some N is released into the air in gaseous forms (N2, N2O, and NO), whereas the P cycle is sedimentary: P does not exist in gaseous forms and is primarily adsorbed to the surfaces of suspended particulate matter and sediments in water [24].
Table 6 and Table 7 show that 7.74–32.5% of the N input was “missing.” Numerous studies on N and P budgets reported similar results [42]. This may be related to denitrification and percolation [43]. Previous reports indicate that N output by denitrification and percolation can constitute 7–30.0% and 0.1–1.28% of the TN input, respectively [21,39]. Denitrification involves microorganisms using organic compounds as carbon sources and electron donors to reduce nitrites and nitrates into gaseous N [44], which can be categorized as anaerobic or aerobic [6]. In addition, aerobic denitrification processes are more obvious when the dissolved oxygen (DO) concentration is above 2.0 mg/L, and a high DO concentration can improve the aerobic denitrification process [45]. The aquaculture water body has a high DO content (DO: 4.85–5.35 mg/L) (Table 2). Therefore, a completely aerobic denitrification process took place in this study, and its main product was N2. Denitrification is affected by multiple environmental parameters, such as temperature, pH, DO, microbial abundance, and community composition [46], resulting in significant differences in the proportions of “missing” N between various treatment groups. The difference between P input and output is marginal because no gaseous phase is present in the P cycle, and such differences are primarily associated with percolation or calculation errors [47].

4.2. N and P Accumulation

The water in the aquaculture system is periodically replaced to maintain a good aquaculture environment, and the amounts of N and P accumulated in the water are generally low. Nevertheless, the replacement of water in aquaculture systems requires high consumption of water resources. An estimation by Yang [48] shows that approximately 4.77 × 104 and 3.75 × 103 tons of N and P, respectively, are discharged every year when the water in mariculture systems in China is replaced. This adversely affects the surrounding environment. Although the water was not replaced during the aquaculture process in this study, the amounts of N and P accumulated in the final water body were 0.08–0.62 g/m2 and 0.08–0.90 g/m2 (Table 7), respectively, which were significantly lower than those in O. niloticus monoculture ponds [26] and tilapia-Chinese Carps polyculture ponds [28]. This indicates that the polyculture of O. niloticus, A. nobilis, and C. quadricarinatus could effectively reduce the water pollution caused by pond aquaculture. The amounts of N and P accumulated in the water body in treatment CHC2 were notably lower than those in the other treatment groups (p < 0.05), and the amounts of N and P accumulated in the water body in treatment CHC2 were reduced by 68.0–87.1% and 20.0–91.1%, respectively. This suggests that the CHC2 model effectively decreased the amounts of N and P accumulated in the water body (Table 7).
Sediment accumulation plays an essential role in N and P outputs. In this study, more N accumulated in the sediment for CH than in those of the other treatments (p < 0.05). This was 23.2–46.8% higher than that in the polyculture model of three species. This can be explained by the residual feed and feces of O. niloticus settling directly at the bottom of the pond and promoting plankton growth. The inorganic nutrients released by the residual feed and feces of O. niloticus promote the growth of plankton, which is an important source of sediment and detritus [6]. In the polyculture model of three species, C. quadricarinatus could feed on and utilize detritus (such as residual feed and feces) to reduce the amount of N accumulated in the sediment. However, the amounts of P accumulated in sediment were similar in the different treatments, (p > 0.05), which could be attributed to the sedimentary cycle caused by the strong affinity of sediment for phosphorus.

4.3. Suitable Breeding Ratio and N and P Utilization Efficiencies

Compound pond breeding of tilapia culture is a common aquaculture practice in China. However, people still rely on experience in the selection of different mixed breeding varieties and stocking proportions. This study showed that there were some differences in the growth, survival rate, and yield of cultured fishes under different mixed breeding modes. In each treatment group, the size, survival rate, and yield of O. niloticus and C. quadricarinatus and the total output of breeding organisms showed first an increasing and then a decreasing trend with the increases in the C. quadricarinatus mixed breeding ratio (Table 3). Among them, the CHC2 group had the highest yield, which was significantly higher than that of the other treatment groups, while the CHC3 group had the lowest yield. Therefore, in the compound breeding system of O. niloticus, A. nobilis, and C. quadricarinatus, the excessive stocking density of C. quadricarinatus has a negative effect on the system output value. The comprehensive benefit and yield of the CHC2 group were significantly higher than those of other the other compound breeding models. They were especially higher than those measured for tilapia single culture [26,28], tilapia co-culture with Hypophthalmichthys molitrix and A. nobilis [13], and tilapia co-culture with A. nobilis + shrimps (Macrobrachium rosenbergii, Penaeus vannamei and Metapenaeus ensis) [9]. Our findings are consistent with the results of a previous study on N and P budgets in the polyculture systems of snakehead with bighead carp [24].
Nitrogen and P are important nutrient elements affecting the aquaculture system. Their effective utilization rates and conversion accumulation are often used as important indicators to evaluate the aquaculture level, aquaculture mode, and the pollution degree of aquaculture. They have important theoretical and practical significance for in-depth study of the inputs and outputs, income and expenditure conversion, and utilization rate of aquaculture ponds [49]. The contents of dry matter, N, and P of the experimental organisms increased to different degrees (p < 0.05) at harvest (Table 4), and the content of dry matter, N, and P in the sediment decreased to different degrees (p < 0.05) (Table 5). This indicates that breeding organisms absorb organic matter from artificial feed or breeding systems (such as plankton and sediment). This is consistent with the results of a tilapia single culture pond study [50]. In addition, the N and P utilization efficiencies in CHC2 were greater than those in the control group (CH) (p < 0.05). The N and P utilization efficiencies in the polyculture model of the three species (CHC2) were 2.56–12.8% and 6.62–11.0% greater than those of the control, respectively. Various forms of N can be utilized by aquaculture organisms in a polyculture system. Oreochromis niloticus consumes pellet-based feed, and its residual feed and feces settle to the bottom of the water body to provide food for C. quadricarinatus. The nutrients released by residual feed for O. niloticus can promote plankton growth to provide food for A. nobilis. Cherax quadricarinatus dwells in the benthic zone, causing the bioturbation of sediment to promote the re-release of N and P [51], which promotes plankton growth once again so that the N and P can be repeatedly recycled at various nutrient levels.
In this study, the N and P utilization efficiencies of farmed animals were 31.20–35.20% and 13.6–15.1%, respectively. These results are consistent with those obtained by Tian [52] and Sahu [18], and greater than those obtained in intensive O. niloticus aquaculture systems [26] and other fish fishing systems [24,27,41]. The ratio of different organisms is a critical factor in polyculture systems. This study revealed that the N and P utilization efficiencies of C. quadricarinatus varied at different stocking densities; CHC1 could not fully utilize N and P at a low stocking density, while an excessive C. quadricarinatus stocking density (CHC3) led to the inhibition of the growth and survival of the farmed fish, and decreased the N and P utilization efficiencies. CHC2 (O. niloticus, 4.0 ind/m2; A. nobilis, 0.15 ind/m2; and C. quadricarinatus, 3.0 ind/m2) exhibited high ecological efficiency and possible economic benefits could be inferred. This suggests that the polyculture of the three species may be a highly effective aquaculture model.

4.4. Pollution Production Coefficient and Environmental Impact of Different O. niloticus and Breeding Modes

An aquaculture pond is an artificial or semi-artificial ecosystem, and the productivity of the system, the material cycling characteristics and output, the degree of pollution, and its impact on the surrounding environment are closely related to its aquaculture mode. Different aquaculture varieties and aquaculture modes have a great impact on the N and P loads in the aquaculture environment [44]. In this study, the pollution production coefficients of TN and TP in O. niloticus and the polyculture pond were 5.35–6.26 g/m2 and 1.17–1.61 g/m2, respectively, according to the material balance method. Among the treatments, the TN production coefficients of O. niloticus and the ternary polyculture groups (CHC1, CHC2, and CHC3) were lower than that of the control group (CH), and this result was lower than the values for O. niloticus in a single raised pond [28], in a prawn + tilapia mixed pond [53], and in a shrimp and crab mixed pond [54]. The TP production coefficient was slightly higher in the control group (CH); this is consistent with the results of a study by Zhong [28]. Pond sediment is an important reservoir for the main biogenic factors such as N and P in ponds, and it is also a secondary pollution source of aquaculture water eutrophication. Disturbances or changes in the environmental conditions have an important influence on the aquaculture water environment [36]. Therefore, the pond sediment production coefficient can be used to evaluate the pond breeding model. This study showed that the N and P pollution coefficients (KTN and KTP) of the CHC1, CHC2, and CHC3 groups were lower than those of the control group (CH), according to the area method. The values were lower than those of a tilapia monoculture pond reported by Meng [36] and prawn intensive ponds reported by Yang [55]. Meanwhile, they were consistent with the values of the complex pond reported by Zhong [28]. The latter study concluded that the pollution coefficients of N and P pollution in breeding ponds and sediments are related to factors such as breeding varieties, breeding modes, breeding pond age, and feeding strategy. The pond compound breeding mode is significantly better than the single breeding mode [28,36]. Our findings confirm this view, with the CHC2 group being the optimal breeding mode in terms of the breeding benefit, N and P utilization rate, and pollution coefficient.

5. Conclusions

This study conducted land-based enclosure experiments to investigate the N and P budgets of O. niloticus, Aristichthys nobilis, and C. quadricarinatus at different stocking densities in a polyculture system. The statistical analyses indicated that the inputs of N and P from feed were 98.2–98.3% and 99.4–99.6%, respectively, and 55.2–65.6% of the N and 81.0–83.4% of the P outputs accumulated in the sediment. Hence, this study indicates that the feed was the main source of N and P inputs in the pond system. The CHC2 group (stocking density: O. niloticus, 4 ind/m2; A. nobilis, 0.15 ind/m2; and C. quadricarinatus, 3 ind/m2) was the optimal mode for breeding benefits, N and P utilization rates, and pollution coefficient, and had greater ecological efficiency and economic benefits. Meanwhile, further research is required to determine the underlying mechanisms of the nutrient salt utilization efficiency of A. nobilis and C. quadricarinatus by performing C and N stable isotopic analysis. This should include the utilization of suspended particulate waste and sedimented particulate matter generated in the Nile tilapia composite culture pond system.

Author Contributions

Conceptualization, X.H., B.L. and K.Z.; methodology, X.H., B.L. and G.W.; software, B.L. and K.Z.; validation, B.L., G.W. and X.H.; formal analysis, B.L.; investigation, B.L. and X.H.; resources, B.L.; data curation, G.W. and B.L.; writing—original draft preparation, X.H., B.L., K.Z. and G.W.; writing—review and editing, X.H., B.L., K.Z. and G.W.; visualization, B.L. and K.Z.; supervision, X.H.; project administration, B.L. and G.W.; funding acquisition, B.L. All authors have read and agreed to the published version of the manuscript.

Funding

This work was supported by the National Natural Science Foundation of China (31972797); the Marine Fisheries Science and Technology Promotion Project of Guangdong Province, (Project A201700B11); the Fundamental Research Funds for the Central Universities (Project 2662023SCPY004).

Data Availability Statement

The data that support the findings of this study are openly available.

Acknowledgments

The authors thank the four reviewers for their positive assessment of our paper and their constructive comments, which helped us improve it. The authors would also like to thank Zhuhai Deyang Aquaculture Co., Ltd., for providing the experimental pond, and the laboratory engineers Qiu Jianji, Fang Zhangsheng, and Ding Yuexiu for their logistical and technical support.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Sherif, A.H.; Prince, A.; Seida, A.A.; Sharaf, M.S.; Eldessouki, E.A.; Harfoush, M.A. Moringa oleifera mitigates oxytetracycline stress in Oreochromis niloticus. Aquac. Res. 2022, 53, 1790–1799. [Google Scholar] [CrossRef]
  2. Doan, H.V.; Hoseinifar, S.H.; Naraballobh, W.; Jaturasitha, S.; Tongsiri, S.; Chitmanat, C.; Ring, E. Dietary inclusion of orange peels derived pectin and Lactobacillus plantarum for Nile tilapia (Oreochromis niloticus) cultured under indoor biofloc systems. Aquaculture 2019, 508, 98–105. [Google Scholar] [CrossRef]
  3. Rahman, M.M.; Nagelkerke, L.A.J.; Verdegem, M.C.J.; Abdul Wahab, M.; Verreth, J.A.J. Relationships among water quality, food resources, fish diet and fish growth in polyculture ponds: A multivariate approach. Aquaculture 2008, 275, 108–115. [Google Scholar] [CrossRef]
  4. Storer, T. Ethology and Production of Freshwater Crayfish in Aquatic Polysystems in Western Australia. Ph.D. Thesis, Curtin University, Singapore, 2005. [Google Scholar]
  5. Troell, M.; Joyce, A.; Chopin, T.; Neori, A.; Buschmann, A.H.; Fang, J.-G. Ecological engineering in aquaculture Potential for integrated multitrophic aquaculture (IMTA) in marine offshore systems. Aquaculture 2009, 297, 1–9. [Google Scholar] [CrossRef]
  6. Zhang, Q.L.; Liu, Y.; Ai, G.M.; Miao, L.L.; Zheng, H.Y.; Liu, Z.P. The characteristics of a novel heterotrophic nitrification-aerobic denitrification bacterium, bacillus methylotrophicus strain L7. Bioresour. Technol. 2012, 108, 35–44. [Google Scholar] [CrossRef] [PubMed]
  7. Mi, H.F.; Wen, Y.H.; Ge, X.P.; Sun, R.J. Current situation and development trend of bighead fish culture in the Pearl River Delta region. Sci. Fish Farming 2016, 10, 82–84. [Google Scholar]
  8. Zhang, Z.; Shi, Y.; Zhang, J. Experimental observation on the efects of bighead carp (Hypophthalmichthys nobilis) on the plankton and water quality in ponds. Environ. Sci. Pollut. Res. 2002, 29, 19923–19925. [Google Scholar]
  9. Liu, B.H.; Fang, Z.S.; Qiao, B.H.; Qiu, J.J. Economic benefit analysis of Nile Tilapia Polyculture model. Ocean Fish 2020, 9, 182–183. [Google Scholar]
  10. Sha, T.A.; Dar, C.J.Y. Feral populations of the Australian Red-Claw crayfifish (Cherax quadricarinatus von Martens) in water supply catchments of Singapore. Biol. Invasions 2007, 9, 943–946. [Google Scholar]
  11. Mai, W.; Wang, C.; Zhong, X.Q. Culture experiment of Australian freshwater crayfish mixed with conventional freshwater fish. Sci. Fish Farming 2019, 35, 80–81. [Google Scholar]
  12. Wang, M.D.; Meng, L.X. Research Progress on Breeding Cherax quadricarinatus. Aquaculture 2021, 6, 35–38. [Google Scholar]
  13. Coronado-Castro, E.; Silva-Ledezma, L.; Gasca-Leyva, E. Economic analysis of polyculture tilapia and Australian redclaw crayfish. In Proceedings of the IIFET 2010, Montpellier, France, 13–16 July 2010; pp. 1–10. [Google Scholar]
  14. Karplus, I.; Barki, A.; Cohen, S.; Hulata, G. Culture of The Australian Red-Claw Crayfish (Cherax quadricarinatus) in Israel Crayfish Incorporation into Intensive Tilapia Production Units. Isr. J. Aquac.-Bamidgeh 2001, 53, 23–33. [Google Scholar] [CrossRef]
  15. Brom, R.E.; Alon, N.C. Polyculture of Nile tilapia (Oreochromis niloticus) and Australian red claw red claw (Cherax quadricarinatus) in earthen ponds. Aquaculture 1994, 1, 47–54. [Google Scholar]
  16. Karplus, I.; Barki, A.; Cohen, S.; Hulata, G. Culture of the Australian red-claw crayfish (Cherax quadricarinatus) in Israel. I. Polyculture with fish in earthen ponds. Isr. J. Aquac. Bamidgeh. 1995, 47, 6–16. [Google Scholar]
  17. Anderson, D.M.; Glibert, P.M.; Burkholder, J.M. Harmful algal blooms and eutrophication: Nutrient sources, composition, and consequences. Estuaries 2002, 25, 704–726. [Google Scholar] [CrossRef]
  18. Sahu, B.C.; Adhikari, S.; Dey, L. Carbon, nitrogen and phosphorus budget in shrimp (Penaeus monodon) culture ponds in eastern India. Aquac. Int. 2013, 21, 453–466. [Google Scholar] [CrossRef]
  19. Boyd, C.E. Chemical budgets for channel catfish ponds. Trans. Am. Fish. Soc. 1985, 114, 291–298. [Google Scholar] [CrossRef]
  20. Krom, M.D.; Neori, A. A total nutrient budget for an experimental intensive fish-pond with circularly moving seawater. Aquaculture 1989, 83, 345–358. [Google Scholar] [CrossRef]
  21. Dong, J.; Tian, X.L.; Dong, S.L.; Zhang, K.; Feng, J.; He, R.P. Study on nitrogen and phosphorus budget on different polyculture system of Litopenaeus vannamei and Portunus trituberculatus. J. Ocean Univ. China 2013, 43, 16–24. [Google Scholar]
  22. Sahu, B.C.; Adhikari, S.; Mahapatra, A.S.; Dey, L. Carbon, nitrogen, and phosphorus budget in scampi (Macrobrachium rosenbergii) culture ponds. Environ. Monit. Assess. 2013, 185, 10157–10166. [Google Scholar] [CrossRef]
  23. Zhang, K.; Tian, X.L.; Dong, S.L.; Feng, J.; He, R.P. An experimental study on the budget of organic carbon in polyculture systems of swimming crab with white shrimp and short necked clam. Aquaculture 2016, 451, 58–64. [Google Scholar] [CrossRef]
  24. Zhang, K.; Xie, J.; Yu, D.G.; Wang, G.J.; Yu, E.R.; Li, Z.F.; Gong, W.B.; Wang, C.C.; Xia, Y. A comparative study on the budget of nitrogen and phosphorus in polyculture systems of snakehead with bighead carp. Aquaculture 2018, 483, 69–75. [Google Scholar] [CrossRef]
  25. Yi, Y. Hybrid catfish (Clarias macrocephalus × C-gariepinus) and Nile tilapia (Oreochromis niloticus) culture in an integrated pen-cum-pond system: Growth performance and nutrient budgets. Aquaculture 2003, 217, 395–408. [Google Scholar] [CrossRef]
  26. Zhou, L. Study on nitrogen and phosphorus budget of intensive tilapia ponds in two culture models. Ph.D. Thesis, Guangdong Ocean University, Zhanjiang, China, 2010. [Google Scholar]
  27. Li, J.W.; Dong, S.L.; Gao, Q.F.; Zhu, C.B. Nitrogen and phosphorus budget of a polyculture system of sea cucumber (Apostichopus japonicus), jellyfish (Rhopilema esculenta) and shrimp (Fenneropenaeus chinensis). J. Ocean Univ. China 2014, 13, 503–508. [Google Scholar] [CrossRef]
  28. Zhong, Q.F. The Nitrogen and Phosphorus Budgets in Polyculture Ponds of Tilapia as The Main Species. J. Guangdong Ocean. Univ. 2019, 39, 48–53. [Google Scholar]
  29. Cao, B.; Abakari, G.; Luo, G.; Tan, H.; Xia, W. Comparative analysis of nitrogen and phosphorus budgets in a bioflocs aquaculture system and recirculation aquaculture system during over-wintering of tilapia (GIFT, Oreochromis niloticus). Aquac. Eng. 2020, 89, 102026. [Google Scholar] [CrossRef]
  30. Li, D.S. A Device of Land-Based Experimental Enclosure Used in Ponds. J. Ocean. Univ. Qingdao 1998, 28, 199–204. [Google Scholar]
  31. Laskov, C.; Herzog, C.; Lewandowski, J.; Hupfer, M. Miniaturized photometrical methods for the rapid analysis of phosphate, ammonium, ferrous iron and sulfate in pore water of freshwater sediments. Limnol. Oceanogr. Methods 2007, 5, 63–71. [Google Scholar] [CrossRef]
  32. Tu, X.H.; Xiao, B.D.; Xiong, J.; Chen, X. A simple miniaturised photometrical method for rapid determination of nitrate and nitrite in freshwater. Talanta 2010, 82, 976–983. [Google Scholar] [CrossRef]
  33. Hu, C.Y.; Wang, Z.F.; Lü, H.Y. A method of determination of total phosphate in the seawater and marine sediment. Mar. Environ. Sci. 1999, 18, 48–52. [Google Scholar]
  34. GB/T 6437-2002; Determination of Phosphorus in Feed-Spectphotometry. National Standardization Management Council of China: Beijing, China, 2002.
  35. Xue, L.Z. Transformation and removal effects of nitrogen and phosphorus in the ecological farming model of fish-vegetables-mushroom. J. Sub. Res. Environ. 2014, 9, 15–25. [Google Scholar]
  36. Meng, S.L.; Hu, G.D.; Qu, J.H.; Wu, W.F.; Fan, L.M.; Chen, J.Z. Preliminary Study on the Pollutants Producing Coefficient of Sediment in Tilapia Broodstock Rearing Pond with Monoculture Mode. J. Agric. Environ. Sci. 2010, 29, 1795–1800. [Google Scholar]
  37. Jackson, C.; Preston, N.; Thompson, P.J.; Burford, M. Nitrogen budget and effluent nitrogen components at an intensive shrimp farm. Aquaculture 2003, 218, 397–411. [Google Scholar] [CrossRef]
  38. Casillas-Hernnandez, R.; Ontiveros, C.A.S.; Estrada, M.A.C.; Ibarra-Gámez, J.C.; Lares-Villa, F. Water quality and nutrient budget in experimental closed tilapia Oreochromis niloticus culture systems. Rev. Latinoam. Recur. Nat. 2012, 8, 46–55. [Google Scholar]
  39. Gross, A.; Boyd, C.E.; Wood, C.W. Nitrogen transformations and balance in channel catfish ponds. Aquac. Eng. 2000, 24, 1–14. [Google Scholar] [CrossRef]
  40. Alongi, D.M.; McKinnon, A.D.; Brinkman, R.; Trott, L.A.; Undu, M.C.; Muawanah; Rachmansyah, R. The fate of organic matter derived from small–scale fish cage aquaculture in coastal waters of Sulawesi and Sumatra, Indonesia. Aquaculture 2009, 295, 60–75. [Google Scholar] [CrossRef]
  41. Zhang, K.; Yu, D.G.; Li, Z.F.; Xie, J.; Wang, G.J.; Gong, W.B.; Yu, E.R.; Tian, J.J. Influence of eco–substrate addition on organic carbon, nitrogen and phosphorus budgets of intensive aquaculture ponds of the Pearl River, China. Aquaculture 2002, 520, 734868. [Google Scholar] [CrossRef]
  42. David, F.S.; Proença, D.C.; Valenti, W.C. Nitrogen budget in integrated aquaculture systems with Nile tilapia and Amazon River prawn. Aquac. Int. 2017, 25, 1733–1746. [Google Scholar] [CrossRef] [Green Version]
  43. Lu, J.; Zhang, Y.X.; Wu, J.; Wang, J.H. Nitrogen removal in recirculating aquaculture water with high dissolved oxygen conditions using the simultaneous partial nitrification, anammox and denitrification system. Bioresour. Technol. 2020, 305, 123037. [Google Scholar] [CrossRef]
  44. Hargreaves, J.A. Nitrogen biogeochemistry of aquaculture ponds. Aquaculture 1998, 166, 181–212. [Google Scholar] [CrossRef]
  45. Hu, B.; Quan, J.; Huang, K.; Zhao, J.; Hu, Y. Effects of C/N ratio and dissolved oxygen on aerobic denitrification process: A mathematical modeling study. Chemosphere 2021, 272, 129521. [Google Scholar] [CrossRef] [PubMed]
  46. Kumar, V.S.; Pandey, P.K.; Anand, T.; Bhuvaneswari, R.; Kumar, S. Effect of periphyton (aquamat) on water quality, nitrogen budget, microbial ecology, and growth parameters of Litopenaeus vannamei, in a semi-intensive culture system. Aquaculture 2017, 479, 240–249. [Google Scholar] [CrossRef]
  47. Guo, K.; Zhao, W.; Dong, S.L.; Jiang, Z.Q. Structure of suspended particles and organic carbon storage in jellyfish-shellfish-fish-prawn polyculture ponds. Acta Ecol. Sin. 2016, 36, 1872–1880. [Google Scholar]
  48. Yang, P.; Lai, D.Y.F.; Jin, B.S.; Bastviken, D.; Tan, L.S.; Tong, C. Dynamics of dissolved nutrients in the aquaculture shrimp ponds of the Min river estuary, China: Concentrations, fluxes and environmental loads. Sci. Total Environ. 2017, 603–604, 256–267. [Google Scholar] [CrossRef] [Green Version]
  49. Wang, S.; Gao, S.S.; Jiang, L.L.; Shen, Q.Q.; Feng, J.X. A review of budget and ecological impact of nutruents nitroden and phosphorus in an aquaculture ecosystem. Chin. J. Fish. 2018, 31, 50–58. [Google Scholar]
  50. Li, Y.R.; Wu, X.J.; Huo, S.Y.; Hao, Y.G.; Pang, X.W. Effects of diludin on thegrowth performance and the antioxidant activity of Tilapia nilotia. J. Agric. Unver. Hebei 2003, 26, 11–15. [Google Scholar]
  51. Bortolini, J.L.; Alvarez, F.; Rodríguez-Almaraz, G. On the presence of the Australian redclaw crayfifish, Cherax quadricarinatus, in Mexico. Biol. Invasions 2007, 9, 615–620. [Google Scholar] [CrossRef]
  52. Tian, X.L.; Li, D.S.; Dong, S.L.; Yan, X.Z.; Qi, Z.X.; Liu, G.C.; Lu, J. An experimental study on closed-polyculture of penaeid shrimp with tiapia and constricted tagelus. Aquaculture 2001, 202, 57–77. [Google Scholar] [CrossRef]
  53. Li, Z.J.; Yu, W.; Zhu, C.B.; Wen, G.L.; Ma, G.Z. Study on nitrogen and phosphorus budgets of experimental enclosures with shrimp monoculture and shrimp-tilapia polyculture. J. Saf. Environ. 2012, 122, 50–56. [Google Scholar]
  54. Xia, X.J.; Xu, Z.N.; Lin, X.T.; Xie, Z.Y.; Jin, Z.L. Environmental nitrogen and phosphorus loading and water quality of three culture methods in ponds. Mar. Sci. 2012, 36, 87–92. [Google Scholar]
  55. Yang, Y.P.; Wang, Z.H.; Sun, J.; Hu, M.H. The variation law of aqueous chemical factors and the buddets od nitrogen in the intensive shrimp ponds. Mar. Sci. 1999, 1, 15–17. [Google Scholar]
Water 15 02699 g001 550
Figure 1. N and P utilization efficiencies by cultured animals in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± standard deviation (SD), and different superscripts indicate significant differences (p < 0.05).
Figure 1. N and P utilization efficiencies by cultured animals in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± standard deviation (SD), and different superscripts indicate significant differences (p < 0.05).
Water 15 02699 g001
Table
Table 1. Stocking information for different systems (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2).
Table 1. Stocking information for different systems (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2).
Oreochromis niloticusAristichthys nobilisCherax quadricarinatus
Weight (g)Density (ind/m2)Weight (g)Density (ind/m2)Weight (g)Density (ind/m2)
CH6.22 ± 0.48421.04 ± 3.560.15
CHC16.21 ± 0.52420.27 ± 6.280.151.26 ± 0.091.5
CHC26.18 ± 0.53422.85 ± 4.370.151.26 ± 0.233
CHC36.19 ± 0.48421.14 ± 5.150.151.25 ± 0.214.5
Table
Table 2. Variation in environmental parameters in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). DO: dissolved oxygen; TAN: total ammonia nitrogen; NO3−-N: nitrate nitrogen; NO2−-N: nitrite nitrogen; TN: total nitrogen; PO43−-P: soluble reactive phosphorus; TP: total phosphorus; (): Initial environmental parameters.
Table 2. Variation in environmental parameters in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). DO: dissolved oxygen; TAN: total ammonia nitrogen; NO3−-N: nitrate nitrogen; NO2−-N: nitrite nitrogen; TN: total nitrogen; PO43−-P: soluble reactive phosphorus; TP: total phosphorus; (): Initial environmental parameters.
Environmental
Compartment		ParameterCHCHC1CHC2CHC3
WaterT (°C)23.5–33.4 (27.2 ± 0.4)23.5–33.4 (27.2 ± 0.4)23.5–33.4 (27.2 ± 0.4)23.5–33.4 (27.2 ± 0.4)
DO (mg/L)4.83–8.54 (4.98 ± 0.21)4.97–10.2 (5.17 ± 0.2)5.35–12.4 (5.72 ± 0.75)4.98–13.1 (5.58 ± 0.54)
pH7.07–8.04 (7.27 ± 0.02)7.14–8.31 (7.36 ± 0.01)7.54–8.39 (7.58 ± 0.06)7.32–8.15 (7.41 ± 0.03)
TAN (mg/L)0.043–0.586 (0.331 ± 0.036)0.024–1.285 (0.348 ± 0.031)0.036–1.24 (0.369 ± 0.037)0.028–1.49 (0.368 ± 0.029)
NO3−-N (mg/L)0.019–0.087 (0.081 ± 0.038)0.067–1.12 (0.083 ± 0.052)0.033–1.08 (0.084 ± 0.041)0.124–1.46 (0.083 ± 0.043)
NO2−-N (mg/L)0.018–0.059 (0.003 ± 0.001)0.002–0.044 (0.003 ± 0.001)0.004–0.171 (0.004 ± 0.001)0.003–0.129 (0.003 ± 0.001)
PO43−-P (mg/L)0.005–0.131 (0.091 ± 0.04)0.035–0.179 (0.093 ± 0.007)0.037–0.202 (0.097 ± 0.010)0.027–0.219 (0.107 ± 0.012)
TN (mg/L)0.69–1.731 (1.29 ± 0.041)0.504–1.98 (1.304 ± 0.068)0.815–2.23 (1.32 ± 0.053)0.607–2.16 (1.21 ± 0.073)
TP (mg/L)0.009–0.217 (0.091 ± 0.007)0.042–0.201 (0.122 ± 0.021)0.064–0.254 (0.112 ± 0.013)0.043–0.217 (0.143 ± 0.017)
SedimentTN (g/L)(0.740 ± 0.114)(0.792 ± 0.107)(0.793 ± 0.078)(0.762 ± 0.087)
TP (g/L)(0.683 ± 0.067)(0.629 ± 0.054)(0.617 ± 0.063)(0.621 ± 0.058)
Table
Table 3. Harvesting conditions of cultured animals in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± standard deviation (SD), and different superscripts in the same column indicate significant differences (p < 0.05). FCR: feed conversion ratio.
Table 3. Harvesting conditions of cultured animals in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± standard deviation (SD), and different superscripts in the same column indicate significant differences (p < 0.05). FCR: feed conversion ratio.
GroupOreochromis niloticusAristichthys nobilisCherax quadricarinatusTotal Yield (Ton/hm2)
Size (kg)Survival Rate (%)Yield
(Ton/hm2)		Feed
(Ton/hm2)		FCRSize (kg)Survival Rate (%)Yield (Ton/hm2)Size (kg)Survival Rate (%)Yield (Ton/hm2)
CH0.654 ± 0.017 a89.4 ± 2.23 a23.3 ± 0.734 a30.4 ± 1.151.30 ± 0.110.515 ± 0.0111000.772 ± 0.043---24.1 ± 0.654 a
CHC10.670 ± 0.011 ab90.5 ± 1.72 ab24.2 ± 0.759 ab30.3 ± 1.041.25 ± 0.700.516 ± 0.0111000.774 ± 0.0580.059 ± 0.00752.1 ± 6.76 a0.458 ± 0.009 a25.4 ± 0.749 a
CHC20.684 ± 0.009 b93.2 ± 2.16 b25.5 ± 0.803 b30.6 ± 1.101.20 ± 0.050.517 ± 0.0121000.776 ± 0.1030.057 ± 0.00750.3 ± 8.13 a0.865 ± 0.017 b27.1 ± 0.804 b
CHC30.665 ± 0.014 ab92.5 ± 1.45 ab24.6± 0.784 ab30.3 ± 0.9891.23 ± 0.060.511 ± 0.0141000.766 ± 0.0890.050 ± 0.00632.1 ± 7.85 b0.721 ± 0.012 c26.1 ± 0.814 b
Table
Table 4. Contents of dry matter, N, and P in feed, in Oreochromis niloticus, and in stocked and harvested species in the experiment. Data are presented as the mean ± standard deviation (SD), and different superscripts in the same column indicate significant differences (p < 0.05).
Table 4. Contents of dry matter, N, and P in feed, in Oreochromis niloticus, and in stocked and harvested species in the experiment. Data are presented as the mean ± standard deviation (SD), and different superscripts in the same column indicate significant differences (p < 0.05).
ItemSampling TimeDry Matter (%)N
(Dry Matter)		P
(Dry Matter)
Oreochromis niloticusStocked21.8 ± 1.34 a14.4 ± 0.69 a1.46 ± 0.05 a
Harvested22.6 ± 1.64 a15.6 ± 0.77 b1.78 ± 0.02 b
Aristichthys nobilisStocked20.7 ± 1.94 a11.3 ± 0.48 a1.06 ± 0.009 a
Harvested21.3 ± 1.63 b12.3 ± 0.55 b1.17 ± 0.024 b
Cherax quadricarinatusStocked21.4 ± 1.82 a10.8 ± 0.32 a0.95 ± 0.08 a
Harvested22.8 ± 2.07 b11.7 ± 1.05 b1.15 ± 0.06 b
Feed 93.76.941.31
Table
Table 5. Contents of mud dry matter, N, and P and densities in the sediment of different enclosures before and after the experiment. Data are presented as the mean ± standard deviation (SD), and different superscripts in the same column indicate significant differences (p < 0.05).
Table 5. Contents of mud dry matter, N, and P and densities in the sediment of different enclosures before and after the experiment. Data are presented as the mean ± standard deviation (SD), and different superscripts in the same column indicate significant differences (p < 0.05).
ItemSampling TimeTreatments
CHCH1CH2CH3
Dry matter %Before63.8 ± 3.05 a63.8 ± 3.05 a63.8 ± 3.05 a63.8 ± 3.05 a
After40.3 ± 2.68 b38.3 ± 2.61 b37.5 ± 3.01 b40.5 ± 2.46 b
Density/g.cm−3Before1.83 ± 0.06 a1.83 ± 0.06 a1.83 ± 0.06 a1.83 ± 0.06 a
After1.31 ± 0.03 b1.38 ± 0.04 b1.47 ± 0.03 b1.56 ± 0.05 b
N
(Dry matter)		Before0.27 ± 0.02 a0.27 ± 0.02 a0.27 ± 0.02 a0.27 ± 0.02 a
After1.56 ± 0.08 b1.44 ± 0.06 b1.31 ± 0.02 b1.12 ± 0.03 b
P
Dry matter		Before0.019 ± 0.001 a0.019 ± 0.001 a0.019 ± 0.001 a0.019 ± 0.001 a
After0.094 ± 0.006 b0.103 ± 0.003 b0.097 ± 0.002 b0.104 ± 0.002 b
Table
Table 6. Inputs of nitrogen and phosphorus (g/m2) in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± SD, and different superscripts in the same column indicate significant differences (p < 0.05).
Table 6. Inputs of nitrogen and phosphorus (g/m2) in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± SD, and different superscripts in the same column indicate significant differences (p < 0.05).
SystemsTreatments
CHCH1CH2CH3
N
(g/m2)		Feed203.6 ± 8.43211.6 ± 13.03204.9 ± 11.65211.7 ± 14.37
Animals0.4900.5200.5450.558
Water1.98 ± 0.092.03 ± 0.112.12 ± 0.152.00 ± 0.09
Rain1.041.041.041.04
Total207.1 ± 8.78215.2 ± 13.04208.6 ± 11.38215.3 ± 14.28
P
(g/m2)		Feed47.0 ± 3.2246.5 ± 2.8947.0 ± 2.9846.5 ± 2.16
Animals0.0570.060.0650.068
Water0.13 ± 0.010.14 ± 0.040.16 ± 0.050.18 ± 0.03
Rain0.020.020.020.02
Total47.2 ± 0.11 a46.7 ± 0.07 b47.2 ± 0.02 c46.8 ± 0.03 c
Table
Table 7. Outputs of nitrogen and phosphorus (g/m2) in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± standard deviation (SD), and different superscripts in the same column indicate significant differences (p < 0.05).
Table 7. Outputs of nitrogen and phosphorus (g/m2) in different treatment groups (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± standard deviation (SD), and different superscripts in the same column indicate significant differences (p < 0.05).
SystemsTreatments
CHCH1CH2CH3
N
(g/m2)		Sediment accumulatio123.4 ± 8.43 a94.8 ± 7.54 b65.6 ± 6.36 c90.5 ± 6.19 b
Harvested animals65.8 ± 2.28 a69.4 ± 2.67 ab74.0 ± 2.70 b71.1 ± 2.36 b
Water
accumulation		0.620 ± 0.09 a0.410 ± 0.116 b0.080 ± 0.05 c0.250 ± 0.04 d
Absorption 1.01 ± 0.17 a0.96 ± 0.09 a0.71 ± 0.04 b0.76 ± 0.11 b
Seepage2.52 ± 0.21 a1.65 ± 025 b0.37 ± 0.12 c0.34 ± 0.16 c
Volatilization1.28 ± 0.06 a1.18 ± 0.28 a1.06 ± 0.19 ab1.04 ± 0.25 b
Total194.6 ± 9.61 a168.4 ± 7.27 b141.8 ± 6.68 c164 ± 7.12 b
P
(g/m2)		Sediment accumulation37.0 ± 3.22 a36.6 ± 3.35 a34.9 ± 3.90 a35.1 ± 2.47 a
Harvested animals6.50 ± 0.022 a6.85 ± 0.024 b7.31 ± 0.026 c7.02 ± 0.026 d
Water
accumulation		0.14 ± 0.01 a0.10 ± 0.01 a0.08 ± 0.01 b0.90 ± 0.02 b
Absorption 0.27 ± 0.05 a0.18 ± 0.03 a0.11 ± 0.02 b0.15 ± 0.04 b
Seepage0.48 ± 0.11 a0.35 ± 0.07 b0.14 ± 0.02 c0.17 ± 0.03 c
Volatilization----
Total44.4 ± 3.23 a44.1 ± 3.31 a42.5 ± 2.73 a43.34 ± 2.26 a
Table
Table 8. Pollution production coefficients of the ponds (PPCP) and sediment deposition (PPCSD) of tilapia farming with different culture models (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± standard deviation (SD), and different superscripts indicate significant differences (p < 0.05).
Table 8. Pollution production coefficients of the ponds (PPCP) and sediment deposition (PPCSD) of tilapia farming with different culture models (CH: monoculture of Oreochromis niloticus; CHC1: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 1.5 ind/m2; CHC2: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 3 ind/m2; CHC3: O. niloticus, 4 ind/m2, A. nobilis, 0.15 ind/m2, C. quadricarinatus, 4.5 ind/m2). Data are presented as the mean ± standard deviation (SD), and different superscripts indicate significant differences (p < 0.05).
GroupPPCP (g/m2)PPCSD (g/m2)
KTNKTPKTNKTP
CH6.26 ± 0.45 a1.17 ± 0.02 a14.8 ± 0.41 a4.64 ± 0.29 a
CH16.01 ± 0.36 a1.61 ± 0.03 b13.5 ± 0.22 b4.57 ± 0.32 a
CH25.35 ± 0.26 b1.52 ± 0.01 b12.5 ± 0.14 c4.49 ± 0.09 a
CH35.41 ± 0.32 b1.56 ± 0.04 b11.9 ± 1.02 c4.36 ± 0.11 a
Note(s): KTN, total nitrogen pollution coefficient; KTP, total phosphorous pollution coefficient.
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.

Share and Cite

MDPI and ACS Style

Liu, B.; Zhang, K.; Wang, G.; He, X. A Study on Nitrogen and Phosphorus Budgets in a Polyculture System of Oreochromis niloticus, Aristichthys nobilis, and Cherax quadricarinatus. Water 2023, 15, 2699. https://doi.org/10.3390/w15152699

AMA Style

Liu B, Zhang K, Wang G, He X. A Study on Nitrogen and Phosphorus Budgets in a Polyculture System of Oreochromis niloticus, Aristichthys nobilis, and Cherax quadricarinatus. Water. 2023; 15(15):2699. https://doi.org/10.3390/w15152699

Chicago/Turabian Style

Liu, Banghui, Kai Zhang, Guangjun Wang, and Xugang He. 2023. "A Study on Nitrogen and Phosphorus Budgets in a Polyculture System of Oreochromis niloticus, Aristichthys nobilis, and Cherax quadricarinatus" Water 15, no. 15: 2699. https://doi.org/10.3390/w15152699

Note that from the first issue of 2016, this journal uses article numbers instead of page numbers. See further details here.

Article Metrics

Back to TopTop