METHIONINE REPLACEMENT WITH CYSTINE IN DIETS FOR PACIFIC WHITE SHRIMP Litopenaeus vannamei

This study was conducted to verify the use of cysteine for methionine and cystine (free L-Met, free L-Cys) on, cystine availability, replacement effect of methionine in diets of Pacific white shrimp .Seven experimental diets were formulated to contain L-methionine and L-cystine in different proportions (100:0, 90:10, 80:20, 70:30, 60:40, 50:50 and 0:100). The shrimp averaging at 1.10g were randomly distributed into 28 acrylic tanks of 96 L capacity at a density of 15 shrimps per tank. After an 8 week feeding trial, no significant differences were observed in growth performance, feed utilization and survival. In non-specific immunity, no significant differences were found in phagocytic (NBT), penoloxidase (PO) activities and immunoglobulin. Whole-body composition was not significantly different among all the dietary treatments.

In conclusion, dietary cysteine supplementation is possible to replace the methionine up to 100% for Pacific white shrimp.