Cholesterol supplements for Litopenaeus vannamei reared on plant based diets in the presence of natural productivity

A 12-wk feeding trial was conducted with juvenile (0.6 +/- 0.3 g) Pacific white shrimp, Litopenaeus vannamei, to evaluate the need for cholesterol supplements in plant based diets for shrimp reared in an outdoor system in the presence of natural foods. The basal diet was formulated with no fish meal and targeted crude protein levels of 35%. Five levels of supplemented cholesterol (0, 0.02, 0.04, 0.06, and 0.08%) resulted in diets analyzed to contain 0.061, 0.076, 0.110, 0.125, and 0.155% cholesterol. In addition, two levels of phytosterol supplements (0.05, 0.1%) were evaluated. Mean final weights and growth ranged from 19.13 to 20.20 g and 1.52 to 1.61 g/week, respectively. One-way ANOVA showed a significant difference (P <= 0.05) among shrimp fed diets containing the various levels of cholesterol, with diets containing <= 0.076% total cholesterol producing smaller shrimp. No significant differences were detected among treatments with respect to survival, yields or FCR. Performance did not significantly improve when shrimp were offered diets supplemented with 0.06% (0.125% total cholesterol) or higher levels of cholesterol. This would suggest that the cholesterol requirement for L vannamei grow-out lies somewhere between 0.076 and 0.11%, however, a regression analysis predicted the cholesterol requirement for maximum growth to be 0.15% of the diet. Performance of shrimp fed the diets with two levels of phytosterol supplementation was compared to those fed the basal diet (no cholesterol supplementation) and the highest level of cholesterol (0.08%) supplementation. Mean final weight and growth rates were significantly different (P <= 0.05) with the mean final weights of the lowest phytosterol inclusion (0.05%) and the 0% cholesterol supplementation being similar, 19.03 and 19.13 g, respectively and the highest levels of phytosterol (0.1%) and cholesterol (0.08%) supplementation being similar, 20.18 and 20.20 g respectively. Likewise, the growth per week showed a similar trend, with the two lower levels of ingredient inclusion resulting in a growth rate of 1.52 g/week and the higher levels achieving a growth rate of 1.61 g/week. Survival, yield, and FCR were not significantly different between treatments. (C) 2011 Elsevier B.V. All rights reserved.