Abstract
The present study evaluated the possible synergistic impacts of sodium butyrate and Spirulina platensis as a feed additive on growth performance, carcass composition, blood health, and intestinal histomorphology of Nile tilapia (Oreochromis niloticus). A control and three treated diets were supplemented with sodium butyrate (SB) 350 mg, Spirulina platensis (SP) lg and a mixture of 350 mg SB and lg SP/kg diet (SB/SP) respectively, were fed for monosex Nile tilapia (12.5 +/- 0.50 g, n=120) for two months. The results revealed higher growth performance (final weight, weight gain, weight gain rate, SGR and PER) compared to control group (CG) (P<0.05), with higher values being observed in fish fed SB/SP, and significant improvement in FCR and ECR values with the lowest values being recorded in fish fed SB/SP followed by SP, SB and CG. Biometric indices showed no significant effect except for fish length, the longest fish length was recorded in fish fed SB/SP followed by SP, SB and CG. There was a significant correlation (P<0.05) between the length and the weight among the experimental groups. Carcass composition showed highest value of total lipid content in fish fed SB/SP. Hematological parameters showed no significant differences except for the WBCs which decreased significantly in fish fed SB or/and SP in respect to CG (P < 0.05). Biochemical parameters of Nile tilapia showed the highest values of total protein and globulin in fish fed SB/SP and the lowest values of triglycerides, AST and ALP in fish fed SB/SP. Intestinal histomorphology showed significant increase in the intestinal villi length, villi surface area and goblet cells count and decreased inter-villi space in SB or/and SP in respect to CG. Conclusively, results revealed the importance of both SB and SP in tilapia diets to enhance the growth, intestinal histomorphology and fish health.