흰다리새우(Litopenaeus vannamei) 사료 내 메티오닌/시스틴의 적정 첨가비에 관한 연구

Abstract

This study was conducted to investigate the proper ratio of methionine and cystine (free L-Met, free L-Cys) on cystine availability, replacement effect of methionine with cystine, growth performance, feed utilization and non-specific immunity of Pacific white shrimp (Litopenaeus vannamei ). Seven experimental diets were formulated to supplement L-methionine and L-cystine in different proportions [Met:Cys; 100:0 (M10C0), 90:10 (M9C1), 80:20 (M8C2), 70:30 (M7C3), 60:40 (M6C4), 50:50 (M5C5) and 0:100 (M0C10). The shrimp (initial weight: 1.10g) were randomly distributed into 28 acrylic tanks of 96 L capacity at a density of 15 shrimps per tank and three groups of shrimps were fed one the experimental diets for 8 weeks. At the end of the feeding trial, no significant difference was observed in growth performance, feed utilization and survival. In non-specific immunity, the results of SOD were significantly higher in M9C1 group than in the M7C3, M6C4, and M5C5 groups. SOD was the lowest in M6C4 group (P <0.05). No significant differences were observed in NBT, PO, anti-protease and lysozyme. The results of the shrimp whole-body composition revealed no significant differences among dietary treatments. In the palatability test, the difference contents or ratio of Met and Cys in the diets did not affect the feed intake of shrimp. In the case of apparent digestibility coefficient of dry matter (ADCd), M8C2 diet group was significantly higher among all diet groups. Shrimp fed the M9C1 diet showed significantly (P <0.05) higher ADC of protein than that of other diet. M6C4 diet group was significantly lowest in ADCd and ADCp. Replacement of Met with Cys in feeds could have any negative effect on the ADCd and ADCp of L. vannamei . Therefore, L-cystine may be useful as an alternative amino acid to L-methionine in feeds for L. vannamei .