Effects of dietary lipid sources on growth performance, fatty acid composition, antioxidant capacity, lipid metabolism and intestinal microbiota of Spinibarbus caldwelli

The present study aimed to evaluate the influence of varying lipid sources on growth performance, serum biochemical indices, muscle chemical composition, antioxidant capacity, lipid metabolism, and intestinal microbiota composition in Spinibarbus caldwelli . Five experimental diets with equivalent nitrogen (40 % crude protein) and lipid (7 % crude lipid) levels were formulated, incorporating distinct lipid sources: fish oil (FO), soybean oil (SO), rapeseed oil (RO), linseed oil (LO), and palm oil (PO). S. caldwelli (initial weight: 8.02 ± 0.02 g) were randomly allocated into 15 tanks (30 fish/tank; 3 replicates per treatment) and fed twice daily (08:00 and 17:30) for 8 weeks. The results were summarized as follows: 1) The SO, RO, and LO groups exhibited significantly higher weight gain rates (WGR), specific growth rate (SGR), and protein efficiency ratio (PER) than the FO and PO groups ( P < 0.05). Notably, the RO group exhibited the lowest feed conversion ratio (FCR). 2) Muscle crude lipid content was significantly elevated in the FO, RO, and LO groups relative to the SO and PO groups ( P < 0.05). 3) Monounsaturated fatty acid (MUFA) levels in muscle were markedly higher in both the LO and RO groups ( P < 0.05). 4) The SO, RO, and LO groups exhibited reduced hepatic malondialdehyde (MDA) content, while catalase (CAT) and superoxide dismutase (SOD) activities were significantly elevated compared to the FO and PO groups ( P < 0.05) . 5) Alpha diversity analysis of the intestinal microbiota revealed that the Shannon and Simpson indices were significantly higher in the SO, RO, and LO groups than those observed in other treatments ( P < 0.05). The LO group displayed a predominance of beneficial bacteria; conversely, while exhibiting greater microbial diversity richness than others, the RO group also contained a higher abundance of harmful bacteria ( P < 0.05). Furthermore, both the RO and LO groups demonstrated the highest enzymatic activities of fatty acid synthase (FAS), hormone-sensitive lipase (HSL), and carnitine palmitoyltransferase-1 (CPT-1) ( P < 0.05). In conclusion, based on growth performance, muscle composition, antioxidant indicators, and microbiota profiles, LO is identified as the optimal lipid source for S. caldwelli diets, followed by FO, RO and SO. PO is not recommended as a dietary lipid source. • LO is the optimal lipid source for Spinibarbus caldwelli diets, outperforming other oils in growth performance, antioxidant capacity, muscle quality, and beneficial gut bacteria prevalence with overall superior efficacy. • Rapeseed oil (RO) and soybean oil (SO) promoted growth but warranted attention to liver health, while palm oil (PO) was unsuitable as a lipid source for Spinibarbus caldwelli diets. • Different lipid sources differed significantly in regulating intestinal microecology.