Effects of ginger (Zingiber officinale) on the growth performance, digestive enzyme activity, antioxidative response, and antibacterial capacity of striped catfish (Pangasianodon hypophthalmus) reared in outdoor conditions

Abstract

Unstable outdoor farming conditions weaken fish's health status and immunity, leading to high susceptibility to infectious diseases and low productivity. Feed additives have been applied recently to enhance the growth performance and well-being of striped catfish. This study evaluated the effects of ginger (Zingiber officinale) on the growth performance, digestive enzyme activity, antioxidative response, and antibacterial capacity of striped catfish. Control and three test diets were supplemented with ginger rhizomes powder at 0.5 %, 1 %, and 1.5 %. After 90 days, the growth performance of striped catfish fed dietary ginger was marginally increased, with the highest being in the group receiving 1 % (p < 0.05). However, the feed conversion ratio was reduced following the same trend, with the lowest being in fish fed at 1 %. Fish fed 1 % ginger had the highest growth hormone level than the remaining groups (p < 0.05). The carcass composition, including total protein and lipids, was meaningfully affected by dietary ginger, while ash and fibers were unaffected. Amylase, protease, and lipase activities were significantly higher in striped catfish fed dietary ginger than in the control. The total protein, albumin, and globulin were significantly higher in striped catfish fed 1 % and 1.5 % ginger than 0 % and 0.5 % (p < 0.05). Superoxide dismutase, catalase, and glutathione peroxidase were significantly higher in striped catfish fed ginger regardless of the dose. On the other hand, the malondialdehyde (MDA) level was markedly reduced by dietary ginger in striped catfish, and those who received 1.5 % had the lowest MDA level. The Vibrio spp. and fecal coliform were markedly reduced by dietary ginger in striped catfish intestines. Interestingly fish fed 1.5 % had the lowest count for Vibrio spp. and fecal coliform. Overall, based on the regression analysis results, dietary ginger should be added at 1.02–1.58 % in the diets of striped catfish to show the best performance and well-being.