Ruminal ecology of swamp buffalo as influenced by dietary sources

Abstract

Four, 3-year old, rumen fistulated swamp buffalo bulls were randomly assigned in a 2 × 2 factorial arrangement in a 4 × 4 Latin square design to received four dietary treatments; factor A = 2 sources of energy (cassava chip and corn cobs), factor B = 2 levels of urea in concentrate mixture (15 and 30 g/kg). During the experiment, concentrate was offered at 5 g/kg BW while 50 g/kg urea-treated rice straw was given on ad libitum basis. Feeds, rumen fluid and rectal feces were collected for chemical analyses during each experimental period (21 days). In addition, rumen fluid was analyzed for, pH, temperature and NH 3-N concentration and microbial population and diversity by using direct count technique, roll-tube technique and molecular techniques including PCR-DGGE and real-time PCR technique. It was found that energy sources and urea levels had no effects on rumen pH, temperature, NH 3-N and total VFA concentrations as well as proportion of individual VFA. Energy sources especially cassava chip had a higher protozoal population than those of corn cob while urea had no effect. The two factors, energy sources and urea levels resulted in similar rumen bacterial and fungal zoospore population. Similarly with nutrient digestion coefficients, there were no differences among treatments, while cassava chip gave a slightly higher intake of urea-treated rice straw than corn cob fed group. Methanogenic and cellulolytic bacteria were variable among treatments and were highest in corn cob with 15 g/kg urea fed group which were higher than those in other groups. In addition, the use of PCR-DGGE has found diversity of rumen microorganisms particularly methanogenic and cellulolytic bacteria. Moreover, using of real-time PCR technique provided that population of Fibrobacter succinogenes had relatively higher than those Ruminococus flavefacieus and Ruminococus albus. Based on this study, corn cob and urea at 15 g/kg could be efficiently utilized in the rumen and thus, could provide good fermentation end-products and improve rumen ecology for the host swamp buffaloes.