Supplementation with 2-hydroxy-4-(methylthio)butanoic acid (HMTBa) in low fish meal diets for the white shrimp, Litopenaeus vannamei

This work evaluated the performance of Litopenaeus vannamei to low fish meal diets supplemented with 2-hydroxy-4-(methylthio)butanoic acid (HMTBa). A basal diet with 150.0 g kg(-1) of anchovy fish meal was designed. Two positive control diets were formulated to reduce fish meal at 50% and 100% with 1.0 and 2.0 g kg(-1) of MERA (TM) Met(Ca) (calcium salt with 84% HMTBa activity), respectively. Two nearly equivalent diets acted as negative controls, without HMTBa supplementation. A total of 50 clear-water tanks of 500 L were stocked with 2.22 +/- 0.19 g shrimp under 70 animals m(-2). Shrimp survival (92.3 +/- 5.1% and 81.4 +/- 8.0%), yield (808 +/- 12 and 946 +/- 17 g m-2) and FCR (2.17 +/- 0.19 and 3.12 +/- 0.37) showed no differences among diets after 72 or 96 days, respectively. A significantly higher shrimp body weight and weekly growth were observed for those fed with the basal diet or diets supplemented with HMTBa compared with non-supplemented ones. This study has shown that L. vannamei growth, body weight, survival, yield and FCR were supported by HMTBa supplementation when 150.0 g kg(-1) of fish meal was replaced by soybean meal and other ingredients, at 50% and 100%.