Effect of dietary mannan oligosaccharide (MOS) on growth, digestive enzymes activity, innate immunity and disease resistance against virulent Aeromonas hydrophila in peninsular carp Barbodes carnaticus (Jerdon, 1849)

Abstract

The effect of dietary mannan oligosaccharide (MOS) on growth, digestive enzymes activity, innate immunity and disease resistance in the Indian minor carp Barbodes carnaticus (Jerdon, 1849) was evaluated over a period of 90 days in soil based cement tanks. B. carnaticus recorded higher weight gain after feeding MOS incorporated diets, with no difference between 0.5 and 1% levels. The feed conversion ratio (FCR) and protein efficiency ratio (PER) were higher with MOS incorporated diets, with the lowest FCR and highest PER recorded by 0.5% MOS diet. Higher activities of hepatopancreatic and intestinal protease, lipase and amylase were recorded in B. carnaticus fed 0.5% MOS diet. The activity showed a decrease at 1% level of MOS incorporation. Carcass proximate composition analysis of B. carnaticus revealed no difference in the moisture, fat and ash contents. However, the crude protein content was higher with MOS treated fish. The group fed with 0.5% MOS recorded significantly higher respiratory burst, alternate haemolytic complement activity (ACH50), lysozyme activity, albumin/globulin (A:G) ratio, myeloperoxidase activity (MPO) and nitric oxide (NO) levels, followed by 1% MOS and Control diets, respectively. The higher relative percentage of survival (RPS) against virulent Aeromonas hydrophila challenge was observed in MOS fed group. The study revealed that MOS supplementation improves the digestive enzyme activity and has got beneficial effect on the growth of B. carnaticus.

Keywords: Barbodes carnaticus, Mannan oligosaccharide, Digestive enzyme, Growth, Innate immunity, Aeromonas hydrophila challenge