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The principal purpose of the present trial is to inspect the complete supply of nutritional fish oil by substituting lipid springs in an applied feed for Thinlip grey-mullet, Liza ramada fingerlings. The impacts of four lipid sources (fish viscera oil (FVO), poultry viscera oil (PVO), tallow oil (TO), and plant oil (PO)) compared with fish oil (FO) as a basal diet on performance growth rates, feed-utilization, biochemical structure of the body, specific blood constraints, and fatty acid profile were evaluated in Thinlip grey mullet fingerlings. The substitution of FO by four substitute lipids shows a non-significant but notable influence on growth performance. On the other hand, feed utilization productivity was significant for fingerlings nourished by the PVO diet. Fingerlings nourished by the PO diet showed significantly lower contents of the total body lipid compared to fingerlings nourished by other diets. Flesh fatty acid structure reflected dietary fatty acids composition. Higher polyunsaturated fatty acids (PUFAs) were detected in fingerlings' flesh nourished by FO, while lower contents were dedicated in fingerlings' flesh nourished by PO. Although saturated fatty acid (SAF) contents in fingerlings' flesh nourished by diet TO were greater than other treatments, these results are beneficial in nutritional design to decrease feed prices without compromising Thinlip grey mullet fingerlings growth.

An 8-week feeding trial was conducted to evaluate the effects of dietary krill oil (KO), fish oil (FO) and soybean oil (SO) on growth, nutritional quality and flavor of the edible meat of the oriental river prawns (Macrobrachium nipponense). The results revealed that SO and KO diets promoted the growth performance (P < 0.05). The activity of alanine aminotransferase in hemolymph of the FO group was significantly lower than that in the SO group (P

The present study aims to investigate the effects of ratios of fish-to-soybean oils in a low fishmeal diet containing Clostridium autoethanogenum protein (CAP) on the growth and metabolism of Litopenaeus vannamei. Four diet groups were designed and the basal diet (FM, 44% crude protein, 8.66% crude lipid, fish-to-soybean oil: 1.5:2.5) contained 25% fishmeal. After 40% of fishmeal protein was replaced by CAP, three different fish-to-soybean oil ratios (4:1, 1:1, and 1:4) were set to formulate three experimental diets, and referred as HF (high fish oil), MF (medium fish oil), and LF (low fish oil), respectively. Shrimp were distributed to four groups of three replicates, each with 40 shrimp in a 300-L tank and they were fed four times daily for 7 weeks before sampling. Results showed that the growth performance of shrimp fed the MF diet was significantly lower than those fed the FM diet, while the shrimp fed the LF diet showed better growth than the HF group. The reduction of the crude lipid content of the whole body, hemolymph total cholesterol (T-CHO), and low-density lipoprotein cholesterol (LDL-C) contents indicated an alteration in the lipid and cholesterol metabolism of shrimp. Compared to the FM group, the mRNA levels of fas in shrimp fed the HF diet were significantly downregulated, while the mRNA levels of delta-24-sr in the HF group were significantly upregulated. In addition, the mRNA levels of hmgcr and scp in shrimp fed the LF diet significantly upregulated compared to the FM group. Metabolomic results showed that multiple metabolic pathways were affected by diet factors, including several amino acid metabolisms, purine metabolism, energy metabolism, and glycerophospholipid metabolism. In conclusion, the reduction of the ratios of fish-to-soybean oils in the low fishmeal diet containing CAP can not only reduce the usage of fish oil and the cost of feed but also maintain the growth performance of shrimp.

An eight-week feeding trial was conducted to investigate the effects of dietary lipid sources on growth performance, fatty acids composition in tissue and expression of genes related to lipid metabolism in juvenile largemouth bass (Micropterus salmoides). Four experimental diets were formulated to contain 6% coconut oil (CO), rapeseed oil (RO), linseed oil (LO) and fish oil (FO), respectively. Each diet was fed to triplicate groups of juvenile for 8 weeks. The results indicated that final body weight (FBW), percent weight gain (PWG), specific growth rate (SGR), feed efficiency (FE), survival, hepatopancreas index (HSI), viscerosomatic index (VSI) and intraperitoneal fat ratio (IPF) were not significantly influenced by dietary different lipid sources (P＞0.05). Moreover, proximate composition in whole body, dorsal muscle and liver were also not significantly affected by dietary different lipid sources (P ＞0.05). Fish fed with FO diet was significantly higher MDA concentration in hepatic and serum than those fed with CO, RO and LO diets (P

Lipid was an essential constituent of aquatic feeds, among which fish oil (FO) was the most excellent lipid source for its nutritive values. However, high price and limited production restricted its application, thus leading to the consideration of developing other alternative lipid sources, and soybean oil (SO) instead of FO was applied as the main lipid source in the commercial feed of grass carp. In the present study, two typical lipids sources FO and SO were used to prepare grass carp feed, and their comparative effects on the growth performance, nutrient composition and metabolic signaling were investigated. The growth performance of two groups exhibited no significant difference, while crude lipid was much higher in the muscle of SO group. Additionally, muscle fatty acid composition of both groups were highly correlated with that of diets, and the proportion of muscle n-3 polyunsaturated fatty acids was notably higher in the FO group, especially that of C20:5n-3 (EPA) and C22:6n-3 (DHA). Comparative digital gene expression profiles (DGE) was conducted and 1261 differentially expressed genes (DEGs) had been identified, then gene ontology (GO) enrichment analysis revealed the enriched functional subterms were primarily focused on cellular metabolic processes and regulation. KEGG pathway analysis elucidated the main metabolism related pathways, and DEGs involved in fatty acid elongation, fatty acid metabolism, and glycerolipid metabolism pathways were listed, including elongation of very long chain fatty acids protein 7 (el7), lysophospholipid acyltransferase 4 (lpcat4), long-chain acyl-CoA synthetase (acs), phosphatidate phosphatase LPIN (lpin), cathepsin L, and glucose-6-phosphate isomerase (gpi) et al. In conclusion, the nutritional composition rather than growth performance of grass carp was affected by different lipid sources, and the underlying regulatory signaling was predicted, which would provide theoretical basis for fish diet formulation.

An six-week feeding trial was conducted to evaluate the effects of dietary n-3 polyunsaturated fatty acid (n-3 PUFA) lipid sources on growth performance, antioxidant capacity, tissue fatty acid profiles, and expression levels of genes involved in lipid metabolism of juvenile green mud crab (Scylla paramamosain) (initial weight 45.3 ± 0.07 g). Three isonitrogenous and isoenergetic experimental diets were formulated to contain fish oil (FO), krill oil (KO) and linseed oil (LO), respectively. The results indicated that crabs fed the KO diet had significantly higher percent weight gain (PWG), specific growth rate (SGR) and feed efficiency (FE) than those fed the LO diet, while no statistic differences were observed between KO and FO diets. Dietary FO could significantly increase the concentrations of malondialdehyde (MDA) and lipid hydroperoxide (LPO) in hemolymph and hepatopancreas compared to dietary KO and LO, similar results were found in the levels of hepatopancreas 8-hydroxy-2-deoxyguanosine (8-OHDG). Crabs fed the KO diet could significantly increase the activities of total superoxide dismutase (T-SOD) and catalase (CAT) in comparison with FO and LO diets. Crabs fed with FO and KO had significantly higher contents of 20:5n-3 (EPA) and 22:6n-3 (DHA) in hepatopancreas and muscle than those fed with LO. While dietary LO could significantly promote the accumulation of C18:3n-3 (ALA) in hepatopancreas and muscle. The anabolic pathway relevant genes: fas and 6 pg d were up-regulated in KO diet. The catabolic pathway relevant genes, hsl, was up-regulated in FO and KO diets, cpt1, was up-regulated in KO diet. Moreover, crabs fed diet supplemented with KO could significantly increase the expression levels of srb2, srebp1 and hnf4α. These findings will provide the reference for the development of the diet for the growth stage of S. paramamosain, and could contribute to deepen the understanding of the physiological metabolism of dietary fatty acids for S. paramamosain.