Effect of direct-fed microbial consortia on ruminal fermentation of maize stover in sheep

摘要

Pure enzymes, antibiotics, probiotics and specific microbial strains which are expensive have been used to manipulate the rumen microbial ecosystem and its fermentation characteristics with limited success. Direct-fed microbial consortia (faecal inoculum from; N1 (horse + wildebeest, 1:1 ratio) and N3 (wildebeest + zebra, 1:1 ratio)) effects on maize stover (MS) degradation, ruminal fermentation characteristics and cellulase enzyme profiles were investigated. In experiment 1, six fistulated male Marino sheep (44 +/- 1.5 kg) receiving 1.3 kg of MS and lucerne (1:0.3 ratio), mineral block and water ad libitum, were randomly assigned to two groups (control and treatment) of three in each. The treatment group were dosed with 50 g (fresh faeces) or 50 ml (cultured faecal inocula) of N1 every 3.5 days through the fistula. Degradation characteristics of MS were measured by incubating 3 g in nylon bags for 96, 72, 48, 24, 12, 9, 6 and 3 h in the rumen of sheep. Rumen fluid was analyzed for ruminal fermentation characteristics (pH, short chain fatty acids (SCFAs), CO2, CH4) and fibre degrading enzymes (exoglucanse, endoglucanse and endoxylanase) specific activities (IU/mg). In experiment 2, feeding was the same as in experiment I but for the inoculum (N3). Exoglucanase and endoglucanase specific activities increased (P<0.05) in N1 (1.1 and 1.8 fold) and N3 (1.3 and 1.5 fold) compared to their controls. Dry matter intake (MS) increased (P<0.03) in N1 but tended to increase (P=0.08) in N3. No differences were observed for the insoluble but degradable fraction of MS, rate of degradation of MS, potential degradability and effective degradability in both N1 and N3 after 96h. Total SCFA and propionic acid tended to increase in N3. Interestingly, CH4 and CO2 were relatively lower in both N1 (3 and 1.9%) and N3 (9 and 1.9%) respectively. Direct-fed microbials from N1 to N3 increased cellulases activity with the potential of increasing DMI. Optimization of microbial consortia can improve livestock productions at a reduced feed cost as the method is cheaper and available to all farmers especially in the developing countries