Dietary mannan oligosaccharides positively affect the growth, digestive enzyme activity, immunity and resistance against vibrio harveyi of pacific white shrimp (Litopenaeus vannamei) larvae

Abstract

This study aimed to determine the effect of dietary mannan oligosaccharides (MOS) delivered through Artemia sp. at different concentrations (i.e. 0, 3, 6 and 12 mg L-1) on the survival, growth, immunity, digestive enzymes and resistance against Vibrio harveyi of Pacific white shrimp larvaein four treatment groups (in triplicates), i.e. control, MOS3, MOS6 and MOS12. Larvae were reared in tank with a dimension of 25 cm × 20 cm × 30 cm containing 4 L of disinfected seawater at a stocking density of 30 larvae L-1. The larvae were maintained until they reached post larval stage for 15 days and were subsequently challenged with V. harveyi (107 CFU mL-1) for 5 days. The survival and growth of the shrimp in MOS treatments were significantly higher (P<0.05) than control. Following challenge test with V. harveyi, the shrimp in MOS treatments demonstrated higher survival, total haemocyte count (THC), phagocytic activity, phenoloxidase and respiratory burst activities than those of the positive control (P<0.05). The digestive enzyme activities in shrimp larvae fed with MOS were higher than those in the control. The increase of digestive enzyme activity was positively correlated with the increase of MOS concentrations with correlation coefficients for protease, lipase and amylase were 0.96, 0.95 and 0.91, respectively (P<0.05). In conclusion, the present study demonstrated that dietary MOS supplementation through Artemia enrichment at the concentration up to 12 mg MOS L-1 could significantly improve Pacific white shrimp post larval digestive enzymes activities, growth, survival and resistance against V. harveyi infection.