Effect of soybean meal replacement by cottonseed meal on growth, feed utilization and some blood physiological/biochemical indices of juvenile black carp,Mylopharyngodon piceus

Abstract

A feeding trial was conducted to evaluate the effect of replacing soybean meal (SBM) with cottonseed meal (CSM) for juvenile black carp. The inclusion levels of CSM were 0 (control), 96.6, 193.3, 289.8 and 386.5 g kg−1, in which 0, 25, 50, 75 and 100% of protein from SBM were replaced with that from CSM respectively. The results showed that up to 75% of SBM could be replaced by CSM without significant reduction in growth. The apparent digestibility coefficients of dry matter and protein, red blood cell and white blood cell count were significantly decreased with the increase in dietary CSM levels (P < 0.05). The activities of serum catalase (CAT), lysozyme (LSZ) and complement C3 were significantly lower than that of control group when dietary CSM level were increased to 386.5 g kg−1, 96.6 g kg−1 and 289.8 g kg−1 or higher respectively. The alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in serum were significantly higher than that of control group when dietary CSM levels were increased to 289.8 g kg−1 or higher (P < 0.05). These results suggested that growth of black carp was not affected when CSM levels up to 289.8 g kg−1; however, negative influence on immune and liver function was found when CSM levels up to 96.6 g kg−1 and 289.8 g kg−1 respectively.