Yeast hydrolysate helping the complex plant proteins to improve the growth performance and feed utilization of Litopenaeus vannamei

Six iso-nitrogenous and iso-lipid experimental diets were formulated to evaluate growth performance, intestinal digestive enzyme activity and the transcript expression of nutrition utilization related genes of the pacific white prawn, Litopenaeus vannamei (initial average body weight: 0.45 +/- 0.01 g). The positive control group (LP) contains the 250.0 g/kg fish meal (FM) and 0 g/kg yeast hydrolysate (YH), negative control group (HP) contains the 150.0 g/kg FM and 0 g/kg YH. The 25, 50, 75, and 100 g/kg FM were replaced by plant proteins in the PY1, PY2, PY3 and PY4 groups, respectively, and 30 g/kg YH was supplemented. At the end of the 56-day feeding trial, there were no significantly difference in weight gain rate and specific growth rate between LP and PY1 (P > 0.05). The protein efficiency rate in PY1 was significantly lower than that in LP (P < 0.05). The glucose, total triacylglycerol and total cholesterol concentrations in HP were significantly higher than those in LP, PY1 and PY3 (P < 0.05). The trypsin, amylase and lipase activities in PY1 were significantly higher than those in LP (P < 0.05). In the intestine, the expression levels of fatty acid-binding protein (FABP) and pyruvate kinase (PK) in PY1 were significantly higher than those in LP, PY2, PY3 and PY4 (P < 0.05). In the hepatopancreas, the expression levels of FABP and PK in PY4 were significantly higher than those in HP (P < 0.05). These results revealed that a diet of the 25 g/kg FM were replaced by complex plant proteins, and 30 g/kg YH was fed, had no negative effects on the growth of L. vannamei, and enhanced digestive enzyme activity and transcript expression of metabolic-related genes, improved the ability to utilize carbohydrates and lipids.