Effects of Mangosteen Peel (Garcinia mangostana) Supplementation on Rumen Ecology, Microbial Protein Synthesis, Digestibility and Voluntary Feed Intake in Cattle

Abstract

Four, rumen fistulated cattle were randomly assigned according to a 4 x 4 Latin square design. The experiment was to study effects of crude saponins and condensed tannins in mangosteen peel on rumen microorganisms and fermentation, microbial protein synthesis and nutrient digestibility in cattle. The dietary treatments were as follows: T1 = Control (without Mangosteen peel supplementation, MSP); T2 = 50 g DM of MSP/hd/d; T3 = 100 g DM of MSP/hd/d; T4 = 150 g DM of MSP/hd/d with urea-treated rice straw (UTS) fed ad libitum. Roughage dry matter intakes in terms of kg/d and %BW were slightly higher in 100 gDM/hd/d supplemented cattle. Apparent digestibilities (%) of DM, OM, CP, NDF and ADF were similar among treatments. The values of ruminal temperature, pH, NH ₃ -N and BUN were not significantly affected by MSP supplementation. However, MSP supplementation increased bacterial population, and was highest at 150 gDM /hd /d supplementation. The protozoal population was significantly decreased while fungal zoospore populations were not changed, and were highest at the 100 gDM/hd/d supplementation group. However, lower values of TVFAs and C2/C3, and higher proportions of C3 were found at 100 gDM/hd/d of MSP supplemented than in the control group. In addition, microbial nitrogen supply, efficiency of rumen microbial protein synthesis and P /E ratio tended to be higher in MSP supplemented groups and were highest at 100 gDM /hd /d MSP supplementation. These results suggest that MSP supplementation at 100-150 gDM/hd/d could be used as a dietary source to manipulate rumen ecology thus improving rumen fermentation and potential productivity in cattle.