Effect of coconut oil and mangosteen peel supplementation on ruminal fermentation, microbial population, and microbial protein synthesis in swamp buffaloes

Abstract

Four rumen fistulated swamp buffalo bulls were randomly assigned to receive dietary treatments according to a 4×4 Latin square design. The four dietary treatments were unsupplementation (control), supplementation with coconut oil (CO) at 50g/kg, supplementation with mangosteen peel (MP) at 30g/kg, and supplementation with CO at 50g/kg and MP at 30g/kg (COM), of total dry matter intake. Animals received concentrate at 10g/kg BW, together with a basal diet of ad libitum rice straw. Feed intake, digestibility of dry matter, organic matter and crude protein were not significantly affected; however, MP supplementation resulted in significantly lower overall NDF and ADF digestibility when compared with COM supplementation. Ruminal pH and BUN concentrations were not significantly different between treatments, while supplementation with CO increased concentration of ruminal NH3–N. Total volatile fatty acid concentrations were increased with MP supplementation. The proportion of ruminal acetic acid was decreased while propionic acid was increased by either CO or COM supplementation. The ruminal protozoal population was dramatically decreased with either CO or MP supplementation; whereas, COM treatment had a lower fungal zoospores population when compared with the control group. Supplementation with MP resulted in a lower population of cellulolytic bacteria than supplementation with COM. In addition, CO supplementation resulted in a higher population of proteolytic bacteria than the control or supplementation with COM. Nitrogen balance and microbial protein synthesis were not affected by CO or MP supplementation. In conclusion, CO or MP supplementation could improve rumen fermentation by positively affecting the ruminal on microbial population in swamp buffalo on rice straw diets.