Partial replacement of fish-meal by soy protein concentrate and soybean meal based protein blend for juvenile Pacific white shrimp, Litopenaeus vannamei

摘要

An 8-week feeding trial was conducted to evaluate the effect of fish-meal replacement on growth performance, whole body composition, apparent digestibility coefficients and anti-oxidative ability of juvenile Pacific white shrimp, Litopenaeus vannamei. Five practical diets were formulated to contain graded levels (5, 10, 15, 20 and 25%) of fish-meal. Soy protein concentrate and soybean meal based protein blend was used to replace fish-meal, amino acids were supplemented in the low fish-meal diet to get similar amino acid profile as the high fish-meal diet. Weight gain, survival, feed conversion rate (FCR), feed intake and protein efficiency ratio (PER) did not show any significant differences between any of the groups. Alanine ratio in whole body were higher in shrimp fed high fish-meal diets while arginine decreased with the increasing fish-meal levels. The Fe content in whole body was significantly lower in shrimp fed the low fish-meal diets, while the other minerals showed no difference among all the groups. Apparent digestibility coefficients (ADC) of dry matter, protein, Ca, P, Cu, Zn and Mg were equal in all the treatments, while ADC of Fe decreased with the decreasing fish-meal levels. When dietary fish-meal decreased, the anti-oxidant related enzymes activity (Total antioxidant capacity (T-AOC) and Catalase (CAT)). Superoxide dismutase (SOD) was unaffected by treatments. Nitric oxide (NO) contents in hemolymph significantly decreased with the decreasing fish-meal levels, while Phenoloxidase (PO) was unaffected. The results indicated that growth performance and apparent digestibility coefficients of nutrients were not affected when fish-meal was replaced from 25% to 5%, but anti-oxidative ability and immune response were damaged after fish-meal level decreased to 15%.