Dietary Use of Monoglycerides Blend in Plant-Based Diets Influences Growth Performance, Hepatopancreatic Histology, Immunity and Disease Resistance of Pacific White Shrimp Penaeus vannamei Against Vibrio harveyi

Abstract

Feeding trials were conducted to evaluate the efficacy of commercially available optimized mixtures of monoglyceride blend (MG, as BalanGut® AQ L supplied by BASF, Germany) on growth performance and health condition of Pacific white shrimp Penaeus vannamei. A basal diet was formulated without MG, and four other diets were prepared by supplementing the powder forms of MG at inclusion levels of 0.5, 0.75, 1,0, and 1,5%. In a growth trial, eight replicate groups of shrimps were hand-fed with one of the diets four times daily for 60 days and observed for growth, total hemocyte count (THC), lysozyme activity, and histomorphological conditions of the hepatopancreas of the shrimp. In a challenge test, diseases challenged with Vibrio harveyi infection at a dose of 1 × 105 CFU mL-1 intramuscularly were conducted and then followed with the observation of the cumulative survival rate after 96 h postchallenge, phenoloxidase, the mean percentage of phagocytic activity and phagocytic index on the blood of the shrimp. In the growth trial, shrimps with inclusion levels of 0,75 up to 1,5% of MG showed significantly higher growth performance than the control treatment. The number of THC and lysozyme activity showed an increasing trend with the inclusion of MG at 0.5 up to 1.0% and then declined with the inclusion of 1.5%. The inclusion of MG did not cause any significant changes in the histomorphology of the shrimp's hepatopancreas. In the challenge test, the lowest survival rate after being infected with Vibrio harveyi was found in the control treatment, and the highest survival rate was found in the group of shrimps fed with 1 MG. The phenoloxidase (PO) activity, phagocytic activity, and index were higher in the group of shrimps fed with MG compared to the control treatment. The results of these studies indicate that the dietary supplementation of 0.75 – 1.0 % of MG can improve the growth, health condition, and disease resistance of P. vannamei.