Dietary sodium butyrate nanoparticles enhanced growth, digestive enzyme activities, intestinal histomorphometry, and transcription of growth-related genes in Nile tilapia juveniles

Feed supplementation is so important to sustain the aquaculture industry. Research studies showed that sodium butyrate used as a feed supplement could improve the growth and health condition of fish. It is hypothesized that the use of sodium butyrate nanoparticles (SB-NP) as a feed supplement may improve the overall fish performance and welfare status than the ordinary-sized one. The current study was done to assess the effects of dietary supplementation with SB-NP on growth, digestive enzyme activities, intestinal histomorphometry, and expression of some growth-related genes of Nile tilapia (Oreochromis niloticus) juveniles. Fish (25.3 ± 0.35 g) were fed on diets supplemented with 0.0 (control), 0.5, 1.0, 1.5, and 2.0 mg SB-NP/kg diet up to apparent satiation (thrice per a day) for eight weeks. Growth–stimulating effects of dietary SB-NP were significantly noted in regard to the final body weight, weight gain percentage, and specific growth rate with optimum levels of 1.0–1.5 mg SB-NP/kg diet. Furthermore, fish groups fed on diets supplemented with SB-NP significantly enhanced the feed intake over those fed on the control diet alongside with no significant differences in feed conversion ratio among the experimental groups. Pairwise comparisons with the control group showed that serum amylase, lipase, and protease activities were significantly increased (P < 0.05) with increasing the dietary levels of BS-NP, and their maximum activities were observed at levels of 1.0–1.5 mg/kg diet. The intestinal histomorphometric features of fish groups fed diets enriched with SB-NP showed increased villi length/width, crypt depth, surface absorption area, and goblet cells than the control group with optimum levels of 1.0–1.5 mg/kg diet. The expressions of growth-related genes in the stomach (ghrelin) and the liver (GH and IGF-1) were significantly (P < 0.05) higher in SB-NP supplemented groups after eight weeks, with highest expressions at 1.0–1.5 mg/kg diet. According to the regression fitting curve, the current study recommends using the dietary SB-NP with optimum values of 1.3–1.5 mg/kg diet to enhance the growth performance with no side effects on the health status of Nile tilapia.