Bile acid supplementation in a high-fat diet improved growth performance, lipid deposition, ferroptosis, and intestinal health in Pacific white shrimp ( Litopenaeus vannamei ).

Abstract

Emerging evidence highlights bile acid (BA) as a key regulator of lipid homeostasis in shrimp, enhancing growth performance in aquaculture. This study aimed to investigate the effects of dietary BA supplementation in high-fat diets on growth performance, lipid deposition, intestinal health, and ferroptosis in Litopenaeus vannamei . An 8-week feeding trial was conducted using, eight different diets formulated with two lipid levels (7% and 11%) and four BA supplementation levels (0, 200, 400, and 800 mg/kg). The diets were named as LFD, LF200, LF400, LF800, HFD, HF200, HF400, and HF800, respectively. A total of 1280 shrimp (0.52 ± 0.01 g) were divided into eight groups with four replicates, stocking 40 shrimp in each replicate tank. Shrimp fed high-fat diets exhibited comparable final body weight (FBW) and weight gain rate (WGR) compared to those fed low-fat diets. However, shrimp receiving 400 mg/kg BA-supplemented diets demonstrated a significant increase in FBW and WGR compared to the high-fat control group ( P < 0.05). Compared to low-fat diets, high-fat diets significantly elevated whole-body lipid content in shrimp and increased hepatopancreatic levels of total cholesterol (T-CHO), triglycerides (TG), and nonesterified fatty acids (NEFA) ( P < 0.05). Additionally, feeding high-fat diets upregulated genes associated with lipid metabolism, such as ampk , fabp , and srebp , in both hepatopancreas and intestines ( P < 0.05). However, the addition of BA was effective in reducing the above indicators ( P < 0.05). Transmission electron microscopy revealed that high-fat diets led to mitochondrial abnormalities in the intestine, including the disappearance of mitochondrial cristae. Immunostaining of the intestine confirmed that high-fat diet markedly reduce the protein expression of GPX4, and the addition of BA significantly up-regulated ferroptosis-related genes- gpx4 and fettrin , enhanced GPX4 protein expression, downregulated the gene expression of acsl4 , and reduced the malondialdehyde (MDA) content ( P < 0.05). Moreover, the addition of BA to high-fat diets restructured the intestinal microbiota, improved intestinal histological structure, and increased the diversity indices of the intestinal microbiota. It also elevated the levels of Tenacibaculum , Motilimona s, Ruegeria , and significantly reduced the relative abundance of Kurthia ( P < 0.05). These findings indicated that dietary BA supplementation may enhance growth performance, lipid metabolism, ferroptosis, and intestinal health of shrimp while mitigating the negative effects of a high-fat diet.