Dietary protease, carbohydrase and micro-encapsulated organic acid salts individually or in combination improved growth, feed utilization and intestinal histology of Pacific white shrimp

Abstract

Abstract The present study evaluated the effects of a protease, a carbohydrase complex and a micro-encapsulated organic acid salt blend in low fish meal diet on growth, nutrient utilization, digestive enzyme activity and intestinal histology of Pacific white shrimp (Litopenaeus vannamei). A positive control diet (PC) and a negative control diet (NC) were designed to contain 20% and 10% fish meal respectively. Then a protease complex (P, 175\u202fmg/kg), a multi-carbohydrase (C, 100\u202fmg/kg) and a micro-encapsulated organic acid salt blend (O, 825\u202fmg/kg) were supplemented to the NC diet individually or in combination to formulate another seven diets (P, C, O, P\u202f+\u202fC, P\u202f+\u202fO, C\u202f+\u202fO, P\u202f+\u202fC\u202f+\u202fO). The nine isonitrogenous and isoenergetic diets were fed to shrimp (2.1\u202fg) for 49\u202fdays. The shrimp fed the PC diet had the highest weight gain (WG) (529.6%) and lowest feed conversion ratio (FCR) (1.20) while those fed the NC diet had the worst growth (382.1% and 1.55, respectively) among the treatments. The supplementation of protease, carbohydrase and micro-encapsulated organic acid salts significantly improved WG and decreased FCR (P\u202f \u202f.05). The findings showed that the individual or combined supplementation of protease, carbohydrase and micro-encapsulated organic acid salts in low fish meal diet (10% fish meal) could improve the growth performance and nutrient utilization of Pacific white shrimp.