Search Results (47)

As consumer demand for quality fish products continues to rise, quality has become a key factor in market competition. Ecological aquaculture research is exploring various farming methods to balance high-quality demand with environmental protection. This study compared three aquaculture models—cage culture (CG), recirculating aquaculture (RAG), and rice–fish co-culture (RG)—by analyzing muscle quality (AOAC, GC-MS), intestinal microbiota (16S rRNA), and liver metabolism (LC-MS) to assess their effects on M. albus. In terms of muscle quality, the RG group showed increased levels of EPA and DHA, reduced muscle moisture and crude lipid content, and enhanced crude protein accumulation. The crude protein content was significantly higher in the RAG group than in the CG group (p < 0.05). The RG group also had the highest levels of total, essential, and umami amino acids, followed by the RAG and CG groups. In terms of intestinal microbiota, the RG group had the highest microbial diversity and stability, with increased abundance of Firmicutes and Bacteroidetes and decreased levels of Proteobacteria. Compared to the CG, the RAG group also showed increased microbial diversity and a reduction in pathogenic genera. Liver metabolomics analysis demonstrated that the RG group had significant advantages over the CG group in amino acid, lipid, and energy metabolism. The RAG group exhibited upregulation of glycerophospholipid metabolism and a decrease in oxidative stress marker levels. Overall, the RG group enhanced muscle quality and optimized intestinal and liver metabolism in M. albus. Full article

Integrated agriculture–aquaculture (IAA), represented by integrated rice–fish farming, offers a sustainable production method that addresses global food issues and ensures food security. Partitioned recirculating renovation based on traditional integrated rice–fish farming is an effective way to facilitate the convenient harvesting of aquatic products and avoid difficulties associated with mechanical operations. To elucidate the impact of partitioned recirculating renovation on the bacterial communities within paddy field ecosystems, we investigated the soil environmental conditions and soil bacterial communities within integrated rice–fish farming, comparing those with and without partitioned recirculating renovations. The findings indicated a significant reduction in the bacterial community richness within paddy soil in the ditch (fish farming area), along with noticeable changes in the relative proportions of the predominant bacterial phyla in both the ditch and the rice cultivation area following the implementation of partitioned recirculating renovation. In both the ditch and the rice cultivation area, partitioned recirculating renovation diminished the edges and nodes in the co-occurrence networks for soil bacterial communities and considerably lowered the robustness index, negatively impacting the stability of bacterial communities in paddy soil. Simultaneously, the partitioned recirculating renovation substantially influenced the bacterial community assembly process, enhancing the relative contributions of stochastic processes such as dispersal limitation, drift, and homogenizing dispersal. In addition, partitioned recirculating renovation significantly altered the soil environmental conditions in both the ditch and the rice cultivation area, with environmental factors being markedly correlated with the soil bacterial community, especially the total nitrogen (TN) and total phosphorus (TP), which emerged as the primary environmental drivers influencing the soil bacterial community. Overall, these results elucidated the ecological impacts of partitioned recirculating renovation on the paddy soil from a microbiomic perspective, providing a microbial basis for optimizing partitioned rice–fish systems. Full article

Rice–fish coculture, a traditional integrated agriculture–aquaculture system, has been recognized as a “Globally Important Agricultural Heritage System” due to its ecological and socio-economic benefits. However, the impact of rice–fish coculture on greenhouse gas emissions remains controversial. This study investigated the effects of rice–fish coculture on methane (CH₄) and nitrous oxide (N₂O) emissions in the Qingtian rice–fish system, a 1200-year-old terraced paddy field system in Zhejiang Province, China. A field experiment with two treatments, rice–fish coculture (RF) and rice monoculture (RM), was conducted to examine the relationships between fish activities, water and soil properties, microbial communities, and greenhouse gas fluxes. Results showed that the RF system had significantly higher CH₄ emissions, particularly during the early rice growth stage, compared to the RM system. This increase was attributed to the lower dissolved oxygen levels and higher methanogen abundance in the RF system, likely driven by the grazing, “muddying”, and burrowing activities of fish. In contrast, no significant differences in N₂O emissions were observed between the two systems. Redundancy analysis revealed that water variables contributed more to the variation in greenhouse gas emissions than soil variables. Microbial community analysis indicated that the RF system supported a more diverse microbial community involved in methane cycling processes. These findings provide new insights into the complex interactions between fish activities, environmental factors, and microbial communities in regulating greenhouse gas emissions from rice–fish coculture systems. The results suggest that optimizing water management strategies and exploring the potential of microbial community manipulation could help mitigate greenhouse gas emissions while maintaining the ecological and socio-economic benefits of these traditional integrated agriculture–aquaculture systems. Full article

Integrated rice–fish farming, crucial for sustainable agriculture, relies on the judicious use of pesticide. This study evaluates the toxicity of six common rice-field pesticides on Procypris merus (rice flower carp), a key species in these systems. We conducted acute and chronic toxicity tests, assessing survival, growth, oxidative stress (SOD, CAT, MDA, 8-OHdG), and neurotoxicity (AChE). Results revealed a spectrum of toxicity: abamectin and trifloxystrobin were highly toxic; pretilachlor was moderately so; and glufosinate-ammonium, triflumezopyrim, and thiazole zinc were low. Notably, triflumezopyrim induced significant oxidative stress and DNA damage, while all three low-toxicity pesticides inhibited AChE activity, indicating potential neurotoxicity. Despite these effects, all observed toxicities were reversible within 7–14 days. Considering that the tested concentrations exceeded typical field application rates, glufosinate-ammonium, triflumezopyrim, and thiazole zinc are deemed relatively safe for P. merus at recommended dosages. Our findings provide critical insights for optimizing pesticide selection in rice–fish farming, balancing pest control with ecological safety, thereby informing sustainable agricultural practices. Full article

The high-input production mode of rice monoculture (RM) has caused severe soil degradation and biodiversity loss, necessitating a transition toward more sustainable practices. The traditional rice-fish co-culture (RF) may provide valuable insights for this situation. However, it remains elusive how long-term RF system influences soil microbial community structure, enzyme activities, and carbon (C) sequestration. Here, a study was conducted at two representative RF areas in Lianshan Zhuang and Yao Autonomous County. At Shatian (P1), three treatments included rice monoculture (RM1) and 2-year and 5-year RF (RF2, RF5). At Gaoliao (P2), the experimental treatments included rice monoculture (RM2) and 15 and 30 years of RF (RF15, RF30). We collected the surface layer (0–20 cm) soils. Then, we analyzed the chemical properties, phospholipid fatty acids (PLFA), and enzyme activities to investigate the effects of their variation on soil C sequestration. The results showed that RF treatments significantly increased soil organic C (SOC) content. Specifically, RF2 and RF5 treatments promoted the SOC content by 4.82% and 13.60% compared with RM1 treatment at P1, respectively; RF15 and RF30 treatments increased the SOC content by 23.41% and 31.93% compared with RM2 treatment at P2, respectively. Additionally, RF5 treatment significantly increased the biomass of the soil microbial community in comparison with RM1 treatment, as did RF15 treatment and RF30 treatment compared with RM2 treatment, including the contents of total PLFA and the PLFA of gram-positive bacteria (G+), gram-negative bacteria (G−), actinomycetes, fungi, and bacteria. Activities of β-glucosidase, cellobiohydrolase, β-1,4-N-acetylglucosaminidase, and urease significantly increased in RF5 and RF30 treatments. The piecewise SEM results indicated that the changes of total PLFA content and the PLFA content ratio of fungi to bacteria were related to contents of dissolved organic C (DOC) and total N (TN) under different RF durations, which are key indicators affecting SOC content. Overall, SOC storage increases with the RF durations, and soil microbial community structure may drive soil C sequestration under long-term RF, which provides a scientific significance and practical value in promoting the sustainability of agricultural ecosystems, enhancing the potential of soil as a carbon sink, and addressing global climate change. Full article

Rice–fish culture, an ancient agronomic practice, integrates aquaculture with rice farming, a sustainable solution for enhancing food security and agricultural productivity. The recent advancements and historical perspectives on rice–fish culture have increased its ecological, economic, and social impacts. The practice spans over 2000 years and has seen significant technological improvements, especially in regions like China, Thailand, and Bangladesh. Implementations of modernized rice–fish systems demonstrate increased rice yields, reduced pest and weed prevalence, improvements in soil quality, and higher profits for farmers. For example, in China, it was reported that a rice–fishing system produced 6000–7000 kg of rice and 1500–7500 kg of fish per hectare per year. Furthermore, the fish reduce herbivore insect abundance and weed abundance, effectively eliminating the need for pesticides. Despite its advantages, challenges such as water management, the availability of quality fish seed, and socio-economic barriers remain. By synthesizing findings from various studies, we will highlight the potential of rice–fish culture to contribute to sustainable agriculture and rural development, recommending strategies for optimizing its adoption and addressing existing constraints. Full article

As global food security issues become increasingly severe, an important innovation in agricultural production patterns, namely integrated rice–fish farming, has been widely implemented around the world, especially in Asia. To assess the impact of integrated rice–crayfish (Procambarus clarkii) farming (IRCF) on agricultural ecosystems, we used Illumina high-throughput 16S rRNA gene sequencing to analyze differences in diversity, composition, co-occurrence network, and assembly process of planktonic bacterial communities in paddy water between traditional rice farming (TRM) and IRCF. Environmental factors and planktonic bacterial communities were evaluated during the tillering, jointing, flowering, and grain-filling stages on August 24, September 5, September 24, and October 16, respectively. Our findings revealed that, throughout the entire cultivation period, IRCF had no notable impacts on bacterioplankton community diversity in paddy water, but it changed the composition and relative abundance of the dominant bacterioplankton. Specifically, IRCF promoted the Chloroflexota during the tillering stage but reduced its presence during the grain-filling stage. It also significantly decreased the Bacillota during the jointing stage while notably enhancing Actinomycetota during the flowering stage. Furthermore, IRCF markedly improved the robustness and negative/positive cohesion within bacterioplankton co-occurrence networks during jointing and grain-filling stages. IRCF altered the assembly processes shaping planktonic bacterial communities, promoting a greater dominance of stochastic processes during the tillering, jointing, and flowering stages and a diminished dominance during the grain-filling stage. IRCF dramatically changed aquatic environmental factors, particularly during the jointing stage, by substantially increasing the TN, ammonium, nitrate, and phosphate levels in paddy water. These nutrient levels were closely correlated with the dynamics of the planktonic bacterial communities. Our findings underscore the considerable potential of IRCF in enhancing the stability of bacterioplankton communities and promoting rice growth while also providing valuable data and theoretical insights into the microbiological ecological impacts of IRCF on the agroecosystem. Full article

Rice-fish farming is an ancient and enduring aquaculture model in China. This study aimed to assess the variations in digestive enzymes, antioxidant properties, glucose metabolism, and nutritional content between Carassius auratus reared in paddy fields and ponds. Notably, the levels of amylase and trypsin in C. auratus from rice paddies were considerably higher compared to those from ponds. Additionally, the hepatic catalase (CAT) activity in fish from paddy (2.45 ± 0.16 U/mg) exceeded that of their pond counterparts (2.27 ± 0.25 U/mg). Regarding glucose metabolism, the activities of key enzymes such as Na+/K+-ATPase (NKA) (paddy: 82.45 ± 6.11 U/g; pond: 78.53 ± 7.18 U/g), hexokinase (HK) (paddy: 9.55 ± 0.58 U/g; pond: 8.83 ± 0.72 U/g), glucokinase (GK) (paddy: 4.09 ± 0.21 IU/g; pond: 3.44 ± 0.33 IU/g), glucose-6-phosphatase (G6Pase) (paddy: 85.71 ± 4.49 IU/g; pond: 79.12 ± 9.34 IU/g), and glucose-6-phosphate dehydrogenase (G6PDH) (paddy: 47.23 ± 3.22 U/g; pond: 42.31 ± 4.93 U/g) were significantly elevated in rice paddy-cultured fish compared to those in ponds. Conversely, phosphor-pyruvate kinase (PK) (paddy: 418.15 ± 31.89 U/g; pond: 570.16 ± 56.06 U/g) activity was markedly reduced in the paddy group. Hepatic glycogen content (paddy: 15.70 ± 0.98 ng/g; pond: 14.91 ± 1.24 ng/g) was also substantially higher in fish from paddy, although no significant differences in muscle glycogen content (paddy: 7.14 ± 0.59 ng/g; pond: 6.70 ± 0.52 ng/g) were observed between the two environments. In terms of nutritional composition, fish raised in paddy exhibited higher crude protein (paddy: 18.46 ± 0.47 g/100 g muscle; pond: 15.57 ± 0.25 g/100 g muscle) and crude ash (paddy: 1.19 ± 0.02 g/100 g muscle; pond: 0.97 ± 0.02 g/100 g muscle) than those in ponds, whereas the crude fat (paddy: 0.87 ± 0.04 g/100 g muscle; pond: 1.66 ± 0.04 g/100 g muscle) was notably lower in paddy fish. Furthermore, fish from rice paddies had a greater total content of monounsaturated fatty acids (MUFA) (paddy: 4.25 ± 0.24 g/100 g muscle; pond: 6.73 ± 0.27 g/100 g muscle), non-essential amino acids (NEAA) (paddy: 9.04 ± 0.3 g/100 g muscle; pond: 7.19 ± 0.21 g/100 g muscle), and delicious amino acids (DAA) (paddy: 7.11 ± 0.2 g/100 g muscle; pond: 5.45 ± 0.19 g/100 g muscle) compared to those from pond cultures. These findings suggest that rice-fish co-culture systems can yield healthier and more environmentally sustainable aquatic products by improving feed digestion and optimizing nutrient metabolism. Full article

Integrated rice–fish farming is an innovative agricultural production pattern that combines rice cultivation with fish farming, enhancing agricultural productivity and ensuring food security. Partitioned rice–fish farming, an advancement of the traditional approach, addresses challenges such as difficulties in fish harvesting and the inconveniences of mechanized operations encountered in paddy fields. To evaluate the environmental impacts of partitioned rice–fish farming on the agricultural ecosystem, we investigated the impacts of partitioned rice–fish farming on the diversity, composition, functionality, co-occurrence networks, and assembly processes of bacterial communities within paddy water. Our results revealed significantly improved Chao1, Observed species, and Pd_faith indices for the bacterial community in the partitioned rice–fish farming system. The relative abundances of the Bacteroidota, Gemmatimonadota, Proteobacteria, and Fluviicola in paddy water were altered by the partitioned system. The partitioned system considerably impacted the bacterial co-occurrence networks within the paddy water, with the planktonic bacterial co-occurrence network in rice cultivation area having more nodes (205) and edges (2085), and its robustness being significantly higher than that of other groups, resulting in a more complex and stable structure of the planktonic bacterial community. In addition, the partitioned system significantly promoted the contribution of stochastic processes to bacterial community assembly in the paddy water, with the main enhanced stochastic processes being homogenizing dispersal and drift. The total proportion of these processes for bacterial community assembly increased from 60% to 70%. Nitrate concentrations in the paddy water were remarkably associated with the water bacterial communities and contributed most to the variations in water bacterial communities. Hence, partitioned rice–fish farming is a feasible and good agricultural production pattern, and from the perspectives of bacterial community diversity and stability it offers both theoretical insights and data-supported foundations for advancing sustainable agricultural practices. Full article

This study investigated the effects of integrating various fish species in a rice field co-culture system on water quality and soil properties. The species included common carp (Cyprinus carpio), Nile tilapia (Oreochromis niloticus), silver barb (Barbonymus gonionotus), snakeskin gourami (Trichopodus pectoralis), and giant freshwater prawn (Macrobrachium rosenbergii). The key water quality parameters measured included water temperature, dissolved oxygen, pH, transparency, ammonia, and nitrite. Soil properties were evaluated through pH, electrical conductivity, organic matter, nitrogen, phosphorus, and potassium. All the selected aquatic animals showed high adaptability in co-culture systems, with survival rates exceeding 80%. Additionally, rice yields increased by approximately 16%, with the highest yield observed in plots stocked with prawns. The results indicated that the presence of aquatic animals enhanced nutrient cycling, leading to significant improvements in both water quality and soil fertility. Differences in water quality and soil properties throughout the culture period were specific to the species present. These findings suggest that rice-fish co-culture systems serve as an effective nature-based solution for enhancing productivity, sustainability, and food security. Full article

Integrated rice–fish farming, an agricultural practice that combines cultivating rice and breeding fish in the same field, has attracted widespread attention. However, there is limited research on how the rice–carp coculture impacts the community structure of phytoplankton and microzooplankton in paddy water. This study employed eDNA metabarcoding sequencing to analyze the composition of phytoplankton and microzooplankton in a rice monoculture system (RM) and a rice–carp coculture system (RF). Following annotation, we identified 9 phyla, 89 families, 275 genera, and 249 species of phytoplankton, along with 20 phyla (or subphyla and classes), 85 families, 222 genera, and 179 species of microzooplankton. The alpha diversity indices revealed significantly higher richness, diversity, and evenness in the RF group compared to the RM group during grain-filling stage. Principal coordinates analysis (PCoA) demonstrated notable differences in the phytoplankton and microzooplankton compositions between the two groups across various rice growth stages. Composition analysis showed that rice–carp coculture increased the relative abundance of dominant phytoplankton phyla such as Bacillariophyta, Chrysophyta, and Euglenophyta while decreasing that of Cryptophyta. In microzooplankton, the coculture resulted in an increased abundance of Intramacronucleata (subphylum) and a decrease in Conoidasida (class). In conclusion, the rice–carp coculture enhances the diversity of plankton, particularly during the grain-filling stage, and simultaneously alters the composition and abundance of dominant plankton species in the paddy water. These findings enhance understanding of the broader impacts of integrated rice–carp farming on agricultural ecosystems, emphasizing alterations in the diversity and composition of aquatic microorganisms Full article

This study compares the food-production efficiencies of integrated rice-fish farming and rice monoculture and evaluates how these farming systems contribute to sustainable food production in the Mekong Delta. The study explores how food-production efficiencies are influenced by the systems’ ecological connectivity by comparing more integrated systems that apply integrated rice-fish farming and integrated pest management (IPM) with less integrated systems farming only rice. Rice-fish farmers with plenty of fish had significantly higher rice yields than farmers with less or no fish, especially during the second crop when the rice was grown together with the fish. A positive correlation between the fish and rice yields, indicated synergistic effects between the fish and rice, due to strengthened ecological connectivity and trophic interactions within the rice-field ecosystem. Overall, rice-fish farmers had higher rice yields than rice farmers, despite using lower amounts of fertilizers and pesticides. They also had lower rice production costs compared to rice farmers, partly because the fish helped fertilize the rice and control rice pests. They had a significantly higher profit and benefit cost ratio than rice farmers because of lower production costs, and high rice and fish yields. The results indicate that food-production efficiencies in the Mekong Delta can be enhanced through diversification and increased ecological connectivity, leading to a more efficient use of rice field ecosystem services that support a long-term and healthy production of food. Full article

Integrated rice–aquatic animal farming has become a vital strategy for enhancing food security. To assess the effects of integrated rice–giant river prawn (Macrobrachium rosenbergii) farming (IRPF) on agricultural ecosystems, we used 16S rRNA gene sequencing to analyze soil bacterial communities in comparison with traditional rice monoculture (RM). Our study revealed that the IRPF did not significantly affect the diversity of the soil bacterial community. However, during the initial culture stage, IRPF markedly increased the relative abundance of the phylum candidate division NC10 and the genus Candidatus Methylomirabilis, enhancing nitrogen-cycling-related functions within the bacterial community. Additionally, IRPF reduced the complexity and stability of these communities in the early to middle culture stages. While stochastic processes usually dominate the assembly of these communities, IRPF restricted bacterial migration and reduced the influence of these stochastic processes. Furthermore, IRPF had a significant impact on environmental factors within paddy soils, strongly correlating with shifts in bacterial communities, particularly through variations in soil nitrite concentration. In conclusion, the influence of IRPF on the bacterial community in paddy soils was primarily observed during the early and middle culture stages, and the impacts of IRPF on the soil bacterial community were primarily driven by environmental changes, especially soil nitrite concentration. These findings provide theoretical insights and a reference for understanding the microbiological impacts of different integrated rice–fish farming systems on agricultural ecosystems. Full article

Cyprinus carpio is a significant freshwater species with substantial nutritional and economic value. Rice–carp co-culture represents one of its principal cultivation methods. However, in the system, the optimal farming density for carp and the impact of high stocking density on their muscle nutritional composition have yet to be explored. Thus, the objective of the current study was to investigate the influences of stocking density on the muscle nutrient profiles and metabolism of C. carpio in rice–fish co-culture systems. Common carp were cultured at three stocking densities, low density (LD), medium density (MD), and high density (HD), over a period of 60 days. Following this, comprehensive analyses incorporating physiological, biochemical, and multi-omics sequencing were conducted on the muscle tissue of C. carpio. The results demonstrated that HD treatment led to a reduction in the antioxidant capacity of C. carpio, while resulting in elevated levels of various fatty acids in muscle tissue, including saturated fatty acids (SFAs), omega-3 polyunsaturated fatty acids (n-3 PUFAs), and omega-6 polyunsaturated fatty acids (n-6 PUFAs). The metabolome analysis showed that HD treatment caused a marked reduction in 43 metabolites and a significant elevation in 30 metabolites, primarily linked to lipid and amino acid metabolism. Additionally, transcriptomic analysis revealed that the abnormalities in lipid metabolism induced by high-stocking-density treatment may be associated with significant alterations in the PPAR signaling pathway and adipokine signaling pathway. Overall, our findings indicate that in rice–fish co-culture systems, high stocking density disrupted the balance of antioxidant status and lipid metabolism in the muscles of C. carpio. Full article

The rice–fish co-culture is an important model of carp farming in China; however, research on the dynamics and assembly of water bacterial communities in this system remains limited. Therefore, this study aimed to explore the dynamics and assembly of bacterial communities, as well as their correlation with environmental factors in paddy water. For these purposes, this study was divided into two groups: a rice–carp co-culture (WRC) group and a rice monoculture (WRM) group, with 20 rice fields in each group. After 60 days of farming, the concentrations of NH₄⁺-N, NO₂⁻-N, TN, and PO₄³⁻ were significantly higher in the WRC group than those in the WRM group. Alpha diversity analysis showed that the Shannon index in the WRC group was significantly decreased compared with the WRM group. At the phylum level, the relative abundance of Actinobacteria significantly increased, while the relative abundance of Proteobacteria and Bacteroidetes significantly decreased in the paddy water of the WRC group. The neutral community model (NCM) indicated that a random process played a dominant role in the construction of bacterial communities in the two groups, and common carp cultivation increased migration rates, thereby affecting community assembly. The co-occurrence network displayed that common carp cultivation led to looser interactions between bacterial communities. In addition, the contents of nutrients significantly affected the abundance of bacteria in paddy water. In summary, carp cultivation decreased the diversity of bacteria and changed the relative abundance of dominant bacteria, thereby affecting the stability and assembly of bacterial communities. Full article