Effect of dietary bile acids: Growth performance, immune response, genes expression of fatty acid metabolism, intestinal, and liver morphology of striped catfish (Pangasianodon hypophthalmus)

Seven isonitrogenous (31.70% protein) and isolipidic (5.20%) experimental diets were made by supplementing a control diet (BA(0)) with 0.25, 0.50, 0.75, 1.0, 1.25, and 1.5 g bile acid (BA) kg(-1) diet, respectively. The diets were fed to striped catfish (Pangasianodon hypophthalmus) to monitor the effects on the growth, non-specific immune response, gene expression of fatty acids metabolism, liver, and their intestinal morphology. The average initial fish weight was 10.3 +/- 0.20 (SD) g. The diets were randomly assigned to 21 hapas, each stocked with 10 fish and fed for 70 days. Supplementing BA(1.0) and BA(1.25) significantly improved growth and nutrient utilization (P < 0.05) compared to BA(0) and other treatments. Additionally, the hematological analyses red blood cell count (RBC), haemoglobin, packed cell volume (PCV) and white blood cell count (WBC) amplified in the subsequent order: BA(1.0), BA(1.25), BA(0.75), BA(1.50), and BA(0.50) g kg(-1) diet and finally BA(0.25) g kg(-1) diet compared to the control diet. The rates of serum lysozyme activity, biochemical parameters, phagocytic index, phagocytic activity, and antioxidants parameters were considerably improved (P <= 0.05) in fish fed diets BA(1.0) and BA(1.25). In the intestinal measurement and liver histomorphometricall, the highest values were observed on BA(1.0) and BA(1.25). Among the five genes assayed in the liver tissues, peritoneal fat, and musculature levels of ATGL, HSL, and CPT-1, genes expression increased in fish fed diets with increasing levels of bile acid added to the diet while, the expression of PPAR alpha and FAS decreased. Consequently, bile acids are recommended at levels of 1.0-1.25 g kg(-1) diet to improve the growth performance and immune status of striped catfish.