Search Results (6)

DHA and EPA, as indispensable n-3 highly unsaturated fatty acids (HUFAs), exert a fundamental influence on regulating fish growth, lipid metabolism, and overall well-being. However, there is a notable lack of data concerning their effects on the F₂ female generation of Yangtze sturgeon. Over a ten-month period, this study assessed the impacts of various dietary concentrations of n-3 HUFAs (0.5%, 1.0%, 1.5%, 2.0%, and 2.4%) on growth, fatty acid composition, lipid metabolism, inflammatory response, and intestinal microbiota in the F₂ female generation of Yangtze sturgeon. Seventy-five test fish, with an average body weight of 3.60 ± 0.83 kg, were housed in 15 ponds, with each dietary group being assigned to three ponds. The results indicated that the 1.0%~1.5% n-3 HUFA group was characterized by the highest values of weight gain rate; serum triglyceride levels peaked in the 0.5% n-3 HUFA group. The fatty acid profiles of the fish tissues closely mirrored those of the diets. Specifically, compared to the 1.5% and 2.0% n-3 HUFA groups, the diet containing 2.4% n-3 HUFA down-regulated the mRNA expression of transforming growth factor beta, and, compared to the 0.5% and 1.0% n-3 HUFA groups, the 2.0% n-3 HUFA diet up-regulated the mRNA expression of nuclear factor kappa B. Conversely, compared to the 0.5% n-3 HUFA group, 2.0% n-3 HUFA in the diet up-regulated the gene mRNA expression of fatty acid binding protein 1 and fatty acid synthase. Compared to the 0.5% n-3 HUFA group, 1.0% n-3 HUFA in the diet up-regulated the gene mRNA expression of lipoprotein lipase. The α-diversity indices (ACE, PD_whole tree, Richness, and Chao1) exhibited an upward trend with increasing dietary n-3 HUFA levels, and the 2.4% n-3 HUFA group reached the highest values. At the phylum level, Fusobacteriota, Proteobacteria, Firmicutes, and Bacteroidota were the primary dominant phyla. Cetobacterium was the dominant genus in all groups. Collectively, these findings underscore that moderate dietary supplementation of n-3 HUFA (1.3%) is optimal and does not impair growth. The deposition of fatty acids in muscle and ovarian tissues, as well as the mRNA expression of lipid-metabolism genes, are closely associated with the dietary n-3 HUFA content. High levels of n-3 HUFA did not suppress intestinal α-diversity. These discoveries provide novel insights into the regulation of growth, lipid metabolism, and health in the F₂ female generation of Yangtze sturgeon and offer a nutritional strategy for the artificial conservation of this endangered species. Full article

Currently, the effects of dietary levels of n-3 highly unsaturated fatty acids (HUFAs) on the growth performance, antioxidant capacity, immunity, and serum oxylipin profiles of female F₂-generation Yangtze sturgeon remain unknown. A total of 75 Yangtze sturgeons, an endangered freshwater fish species, with an average body weight of 3.60 ± 0.83 kg, were randomly allocated to 15 concrete pools, with each dietary group represented by 5 fish per pool. The fish were fed five different experimental diets containing various levels of n-3 HUFAs (0.5%, 1.0%, 1.5%, 2.0%, and 2.4%). After a feeding period of 5 months, no significant differences in the growth performances of the fish were observed among the five dietary groups (p > 0.05). However, we did note that the serum levels of low-density lipoprotein cholesterol (LDL-C), triglycerides (TGs), and total cholesterol (TCHO) exhibited a marked increase in the fish that consumed higher dietary n-3 HUFA levels (p < 0.05). Conversely, alkaline phosphatase (ALP) activities showed a notable decrease as dietary n-3 HUFA levels increased (p < 0.05). Serum antioxidant indices, such as the activity levels of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), were significantly higher in the 2.4% HUFA group compared to the 0.5% HUFA group. Additionally, muscle antioxidant indices, including total antioxidant capacity (T-AOC), catalase (CAT), and SOD activity, exhibited notable increases as dietary n-3 HUFA levels increased (p < 0.05). Furthermore, there was a decrease in malondialdehyde (MDA) levels as dietary n-3 HUFA levels increased (p < 0.05). In relation to immune indices, only serum immunoglobulin M (IgM) and muscle complement 3 (C3) were found to be influenced by dietary n-3 HUFA levels (p < 0.05). A total of 80 oxylipins were quantified, and our subsequent K-means cluster analysis resulted in the classification of 62 oxylipins into 10 subclasses. Among the different n-3 HUFA diets, a total of 14 differential oxylipins were identified in the sera. These findings demonstrate that dietary supplementation with n-3 HUFAs exceeding a 1.0% level can enhance antioxidant capacity and regulate serum lipid metabolism, potentially through modulation of oxylipins derived from ARA, DHA, and EPA. These insights provide novel perspectives on the mechanisms underlying these observations. Full article

This study investigated the effects of dietary commercial feed (n = 50,025 in triplicate, named group PF for soil dike pond, sampling n = 7; n = 15,000 in triplicate, WF for water tank, n = 8), iced fish (n = 50,025 in triplicate, PI, n = 7), and a combination of both (n = 50,025 in triplicate, PFI, n = 8) on different metabolic parameters of the largemouth bass, Micropterus salmoides (0.67 ± 0.09 g, culture period from June 2017 to July 2018). Throughout the experimental period, different areas of water (including input water of the front, middle of the pond, and from the drain off at the back) and their mixed samples were simultaneously analyzed to find the source of the main infectious bacteria. Various feeding strategies may differentially affect body composition and shape the gut microbiota, but the mode of action has not been determined. Results showed that no significant differences were found in the growth performance except for the product yield using a different culture mode (PFI vs. WF). For muscle composition, the higher ∑SFA, ∑MUFA, ∑n-6PUFA, and 18:3n-3/18:2n-6 levels were detected in largemouth bass fed with iced fish, while enrichment in ∑n-3PUFA and ∑HUFA was detected in largemouth bass fed with commercial feed. For the gut microbiota, Fusobacteria, Proteobacteria, and Firmicutes were the most dominant phyla among all the gut samples. The abundance of Firmicutes and Tenericutes significantly decreased and later increased with iced fish feeding. The relative abundance of species from the Clostridia, Mollicutes, Mycoplasmatales, and families (Clostridiaceae and Mycoplasmataceae) significantly increased in the feed plus iced fish (PFI) group relative to that in the iced fish (PI) group. Pathways of carbohydrate metabolism and the digestive system were enriched in the commercial feed group, whereas infectious bacterial disease resistance-related pathways were enriched in the iced fish group, corresponding to the higher rate of death, fatty liver disease, and frequency and duration of cyanobacteria outbreaks. Feeding with iced fish resulted in more activities in the digestive system and energy metabolism, more efficient fatty acid metabolism, had higher ∑MUFA, and simultaneously had the potential for protection against infectious bacteria from the environment through a change in intestinal microbiota in the pond of largemouth bass culturing. Finally, the difference in feed related to the digestive system may contribute to the significant microbiota branch in the fish gut, and the input and outflow of water affects the intestinal flora in the surrounding water and in the gut, which in turn affects growth and disease resistance. Full article

The present study aimed to evaluate the feasibility of a formulated diet to replace live baits as feed for Siniperca chuatsi. A 2 × 2 factorial design with three replicates was used to investigate the effects of conventional live baits (LB) and a formulated diet (FD) on the growth, muscle nutrition composition, and digestive enzyme activities of S. chuatsi at two growth stages. The results showed that the feed conversion ratio (FCR) in the FD group was significantly lower than that in the LB group. The final body weight (FBW) and weight gain (WG) were not significantly different between the two feeding modes. However, at the juvenile stage, the specific growth rate (SGR) in the FD group was significantly lower than that in the LB group. Muscle moisture, crude protein, and crude lipid contents were not influenced by dietary treatments. There were no significant differences in ∑EAA, ∑NEAA, and ∑AA compositions of the juvenile and adult stages fed the two kinds of diets. At the juvenile stage, histidine (His) content in the FD group was significantly higher than that in the LB group; at the adult stage, cysteine (Cys) content in the FD group was significantly higher than that in the LB group; at both growth stages, Met content in the FD group was significantly lower than that in the LB group. The FD group showed higher levels of ∑SFA, ∑HUFA, ∑n-3PUFA, n-3/n-6, EPA, and DHA than the LB group did, whilst the opposite occurred in the MUFA levels. In addition, fish fed with LB had significantly higher values of pepsin and intestinal trypsin activities in the juvenile fish compared to the FD group, but the activities were not significantly different between the two feeding modes at the adult stage. The activities of stomach and intestine amylase in the FD group were significantly higher than those in the LB group. Overall, these results showed that under long-term feeding conditions, S. chuatsi fed with the artificial diet had no significant difference in muscle crude protein, crude lipid, amino acid composition, and digestive capacity, but showed superiority in the composition of fatty acids such as EPA and DHA levels compared to the live baits group. Therefore, the artificially formulated diet might be a more appropriate feeding approach for sustainable development of the S. chuatsi industry. Full article

A 56-day feeding trial to evaluate the responses of red seabream (initial weight: 1.8 ± 0.02 g) to the substitution of fish oil (FO) with camelina oil (CO) at different ratios was conducted. The control diet formulated at 46% CP (6F0C) contained only FO without CO; from the second to the fifth diet, the FO was substituted with CO at rates of 5:1 (5F1C), 4:2 (4F2C), 3:3 (3F3C), 2:4 (2F4C), and 0:6 (0F6C). The results of the present study showed that up to full substitution of FO with CO showed no significant effect on growth variables BW = 26.2 g–28.3 g), body weight gain (BWG = 1275.5–1365.3%), specific growth rate (SGR = 4.6–4.7), feed intake (FI = 25.6–27.8), feed conversion ratio (FCR = 1.0–1.1), biometric indices condition factor (CF = 2.2–2.4), hepatosomatic index (HSI = 0.9–1.1), viscerasomatic index (VSI = 7.5–9.5), and survival rates (SR = 82.2–100) with different FO substitution levels with CO. Similarly, there were no significant differences (p < 0.05) found in the whole-body composition except for the crude lipid content, and the highest value was observed in the control group (291 g/kg) compared to the other groups FO5CO1 (232 k/kg), FO4CO2 (212 g/kg), FO2CO4 (232 g/kg) and FO0CO6 (244 g/kg). Blood chemistry levels were not influenced in response to test diets: hematocrit (36–33%), glucose (Glu = 78.3–71.3 mg/dL), total protein (T-pro = 3.1–3.8 g/dL), total cholesterol (T-Chol = 196.0–241 mg/dL), blood urea nitrogen (BUN = 9.0–14.6 mg/dL), total bilirubin (T-Bil = 0.4–0.5 mg/dL), triglyceride (TG = 393.3–497.6 mg/dL), alanine aminotransferase test (ALT = 50–65.5 UL/L), aspartate aminotransferase test (AST = 38–69.3 UL/L). A remarkable modulation was observed in catalase (CAT) and superoxide dismutase (SOD) activities in the liver, as CAT and SOD values were lower with the complete FO substitution with CO (0F6C), and the highest values were observed in the control and (4F2C). This study indicates that red seabream may have the ability to maintain LC-PUFAs between tissues and diets, and CO substitution of FO could improve both lipid metabolism and oxidation resistance as well as maintain digestibility. In conclusion, dietary FO can be replaced up to 100% or 95% by CO in the diets of red seabream as long as n-3 HUFA, EPA, and DHA are incorporated at the recommended level. Full article

Ruminant fats are characterized by different levels of conjugated linoleic acid (CLA) and α-linolenic acid (18:3n-3, ALA), according to animal diet. Tissue fatty acids and their N-acylethanolamides were analyzed in male obese Zucker rats fed diets containing lamb meat fat with different fatty acid profiles: (A) enriched in CLA; (B) enriched in ALA and low in CLA; (C) low in ALA and CLA; and one containing a mixture of olive and corn oils: (D) high in linoleic acid (18:2n-6, LA) and ALA, in order to evaluate early lipid metabolism markers. No changes in body and liver weights were observed. CLA and ALA were incorporated into most tissues, mirroring the dietary content; eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) increased according to dietary ALA, which was strongly influenced by CLA. The n-3 highly-unsaturated fatty acid (HUFA) score, biomarker of the n-3/n-6 fatty acid ratio, was increased in tissues of rats fed animal fats high in CLA and/or ALA compared to those fed vegetable fat. DHA and CLA were associated with a significant increase in oleoylethanolamide and decrease in anandamide in subcutaneous fat. The results showed that meat fat nutritional values are strongly influenced by their CLA and ALA contents, modulating the tissue n-3 HUFA score. Full article