Effect of chicken gut meal on growth, immune and metabolism in juvenile fat greenling (Hexagrammos otakii)

Abstract

Abstract In modern aquaculture, chicken gut meal (CGM) is reasonably priced and rich in nutrients, and can become a new source of protein in the diets of major aquatic products such as fish and shrimp. An 8-week feeding trial was conducted to comprehensively investigate the beneficial effects of CGM on juvenile fat greenling (Hexagrammos otakii). Juvenile H. otakii (1.58 ± 0.06) g were fed with different levels of CGM in a replacement percentage of fish meal (FM) in the basal diet: 0% (CGM0), 25% (CGM25), 50% (CGM50), 75% (CGM75) and 100% (CGM100). The results showed that the percent weight gain (PWG), specific growth rate (SGR), feeding rate (FR) and feed conversion rate (FCR) were significantly improved among the experimental groups (P < 0.05). Higher hepatosomatic index (HSI) was observed in CGM50, CGM75 and CGM100 groups compared to the control (P < 0.05). The apparent digestibility coefficient (ADC) of dry matter, protein and lipid were significantly increased with CGM inclusion (P < 0.05). Moreover, the activities of superoxide dismutase (SOD) and catalase (CAT) were significantly increased in CGM25 and CGM50 groups, respectively (P < 0.05). The activities of acid phosphatase (ACP) and alkaline phosphatase (AKP) were significantly decreased in CGM75 and CGM100 groups (P < 0.05). Triglyceride (TG) and total cholesterol (TCHO) were significantly increased in CGM50 and CGM75 groups, respectively (P < 0.05). Fish fed in CGM100 and CGM75 groups had higher activities of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) than the control (P < 0.05). Moreover, the relative expression of fatty acid synthase (FAS) and acetyl-CoA carboxylase alphα (ACCα) were significantly increased in CGM75 and CGM100 groups, while hormone-sensitive lipase (HSL) and peroxisome proliferator-activated receptor alpha (PPAR-α) were significantly decreased (P < 0.05). In summary, the optimal replacement level of FM with CGM was shown by curve equation analysis to be 61.30%.