Sodium butyrate supplementation improves growth performance, gut health, hepatic enzyme activities, and disease resistance against Aeromonas hydrophila in Labeo rohita.

Sodium butyrate (SB) is gaining attention as a dietary supplement in aquaculture because of its potential benefits for fish health and growth. This research was conducted to assess the impacts of SB concentrations on the growth, antioxidant status, digestive enzyme activities, gut morphology, hepatic enzyme activities and survival against Aeromonas hydrophila in rohu (Labeo rohita). For this purpose, SB was supplemented at 0.0, 0.5, 1.0, 2.0 and 4.0 g/kg in the basal diet (30.16% crude protein). Thirty acclimatized fingerlings (15.15 ± 0.03 g) were distributed in each of 15 glass aquaria and fed till fish appeared satiated for 60 days in triplicate. The results showed that SB at concentrations up to 1.0 g/kg improved (p < 0.05) growth and feed efficiency; however, higher levels reduced growth and feed efficiency. The activities of protease, lipase and amylase improved (p < 0.05) in the 1.0 g/kg SB group and higher levels reduced activities. The intestinal histomorphometric measurements increased (p < 0.05) up to 1 g/kg SB level and then decreased with higher levels. The fish fed a 1.0 g/kg SB-containing diet presented the highest increase in villus length, width, surface area, and crypt depth. Hepatic enzyme activities decreased up to the 1 g/kg SB level and activities increased with further supplementation. Moreover, improved (p < 0.05) activities of antioxidant enzymes were observed in fish fed with 1.0 g/kg SB diets and higher levels reduced these activities. However, optimal sodium butyrate level for L. rohita was estimated to be 0.68 g/kg (R