Abstract
This study was conducted to comprehensively investigate the beneficial effects of a mannan oligosaccharide product (hereinafter called MOS) on Litopenaeus vannamei and optimum level of MOS. Five isonitrogenous and isolipid diets were formulated by adding 0%, 0.02%, 0.04%, 0.08%, and 0.16% MOS in the basal diet. Each diet was randomly fed to one group with four replicates of shrimp in an 8-week feeding trial. The results showed that dietary MOS improved the growth performance and the ability of digestion of shrimp. Dietary MOS significantly increased the activity of total superoxide dismutase, catalase, and glutathione peroxidase and decreased the content of malondialdehyde in plasma of shrimp. Dietary MOS significantly increased the activity of alkaline phosphatase and lysozyme in plasma and the hemocyte counts. Dietary MOS significantly upregulated the expression of Toll, lysozyme, anti-lipopolysaccharide factor, Crustin, and heat shock protein 70 in the hepatopancreas. And dietary MOS significantly upregulated the expression of intestinal mucin-2, mucin-5B, and mucin-19, while it decreased the expression of intestinal mucin-1 and macrophage migration inhibitory factor. Dietary MOS improved the bacterial diversity; increased the abundance of Lactobacillus, Bifidobacterium, Blautia, and Pseudoalteromonas; and decreased the abundance of Vibrio in the intestine. Shrimp fed MOS diets showed lower mortality after being challenged by Vibrio parahaemolyticus. Notably, this study found a decrease in antibiotic resistance genes and mobile genetic elements after MOS supplementation for the first time. The present results showed that diet with MOS supplementation enhanced the organismal antioxidant capacity and immunity, improved intestinal immunity, optimized intestinal microecology, mitigated the degree of antibiotic resistance, and increased the resistance to V. parahaemolyticus in L. vannamei, especially when supplemented at 0.08% and 0.16%.
Highlights
Pacific white shrimp (Litopenaeus vannamei) have great economic value and are widely farmed throughout the world due to their nutritional value, rapid growth, and high capacity to adapt to the environment [1, 2]
Weight gain rate (WGR) and Specific growth rate (SGR) of shrimp showed an increasing trend with the increase of Mannan oligosaccharide (MOS) level, but no significant difference was observed when compared with the control group (M0) (p > 0.05)
The MDA content in plasma was progressively decreased with the increase of dietary MOS, which had significantly lower values in M4, M8, and M16 compared with M0 (p < 0.05)
Summary
Pacific white shrimp (Litopenaeus vannamei) have great economic value and are widely farmed throughout the world due to their nutritional value, rapid growth, and high capacity to adapt to the environment [1, 2]. There has been an increasing interest in promoting animal health through functional feed additives. The main beneficial effects of MOS were fish performance elevation by stimulation of the innate immune system and improvement of gut functions and nutrient digestibility, partly through reducing colonization of pathogen in the gastrointestinal tract [7,8,9,10]. Studies on shrimp have shown that the addition of MOS in diets was conducive to weight gain, immunity [1, 19,20,21], and digestive enzyme activity [22]. The intestine plays a crucial role in nutrient digestion and absorption as well as disease defense in shrimp and is responsible for nearly 70% of the immune function of shrimp. Few studies have been conducted to investigate the effects of MOS on shrimp intestinal health
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
