Dietary sodium butyrate administration alleviates high soybean meal-induced growth retardation and enteritis of orange-spotted groupers (Epinephelus coioides)

An 8-week feeding trial was conducted to investigate whether dietary sodium butyrate (SB) administration alleviates growth reduction and enteritis of orange-spotted grouper (Epinephelus coioides) caused by high soybean meal (SBM) feeding. The control diet (FM diet) was formulated to contain 48% protein and 11% fat. Soybean meal was used to replace 60% FM protein in FM diet to prepare a high SBM diet (HSBM diet). Sodium butyrate (SB) at 0.1%, 0.2%, and 0.3% were added to HSBM diets to prepare three diets. Triplicate groups of 30 groupers (initial weight: 33.0 +/- 0.3 g) were fed one of the diets twice daily, to apparent satiety. HSBM diets had lowered growth rate and feed efficiency vs FM diets (P <0.05). Growth rate and feed efficiency were improved by dietary SB administration and were in a dose-dependent manner (P <0.05). A similar pattern to the growth rate was observed for plasma LDL-C and gut digestive activity of lipase, trypsin, and protease, but the opposite trend was observed for intestinal contents of D-lactic acid and endotoxin, in response to dietary SB inclusion levels (P >0.05). The muscular thickness in the middle and distal intestines in SB-treated diets were higher than that in HSBM diets (P <0.05). The mRNA levels of intestinal pro-inflammatory cytokines IL-8, IL-1 beta, IL-12 and TNF-alpha had a decreasing trend, and the mRNA level of intestinal anti-inflammatory cytokine TGF-beta 1 had the opposite trend, with increasing SB inclusion levels (P < 0.05). The above results indicate that dietary SB intervention could enhance growth and feed utilization of groupers with SBM-induced enteritis by promoting intestinal digestive enzyme activities, reducing mucosa permeability, maintaining the integrity of intestinal morphology and attenuating the intestinal inflammatory response.

Automated summary

The study found that enteritis had a negative impact on the growth rate and feed efficiency of orange-spotted groupers. However, dietary supplementation with sodium butyrate can improve growth rates and feed efficiency, enhance digestive enzyme activities, reduce intestinal mucosa permeability, and attenuate intestinal inflammatory responses.