Tropical legume supplementation influences microbial protein synthesis and rumen ecology

Abstract

Four rumen-fistulated male swamp buffaloes, 5-year-old with initiated live weight at 360 ± 12 kg, were randomly assigned according to a 4 × 4 Latin square design to investigate the effect of feeding high level of dried Leucaena leaf (DLL) on feed intake, fermentation efficiency and microbial protein synthesis. The dietary treatments were the feeding levels of DLL at 0, 2, 4 and 6 kg/head/day. All buffaloes were supplemented with concentrate mixtures at 0.1% of body weight, and rice straw was fed ad libitum with the availability of water and mineral block at all time. The results revealed that the total feed intake and nutrient digestibility were significantly improved with the increasing levels of DLL feeding, and the highest was in the buffaloes consuming DLL at 6 kg/head/day. Feeding high levels of DLL did not affect on ruminal pH and temperature, while ammonia nitrogen, blood urea nitrogen and volatile fatty acid concentration were significantly enhanced. Moreover, methane production was dramatically reduced by increasing levels of DLL feeding. Total direct counts of the micro-organism population were increased with the increasing levels of DLL feeding. According to the application of quantitative PCR to quantity cellulolytic bacteria (16S rRNA) targets, it was found that the population of total bacteria and Fibrobactor succinogenes was affected by treatments, while Ruminococcus flavefaciens and methanogen population were significantly decreased as buffaloes were fed with DLL. The nitrogen balance and microbial nitrogen supply were remarkably improved with the increasing levels of DLL feeding. Based on this study, it could be concluded that high levels of DLL feeding at 6 kg/head/day could enhance feed intake, nutrient digestibility, rumen fermentation efficiency and microbial protein synthesis in swamp buffaloes fed on rice straw without any adverse effect.

Effect of Dried Leaves of Leucaena leucocephala on Rumen Fermentation, Rumen Microbial Population, and Enteric Methane Production in Crossbred Heifers

“…Treatments 1 and 2 showed a higher BUN compared to treatment 0. In accordance with these results in another study, doses of 0.83% and 1.89% CT increased BUN compared to the control treatment [47]. By contrast, a reduction of BUN at doses below 1.9% CT has been also reported [42], which compares well with the reduction in BUN observed at the dose of 1.2% CT in this trial.…”

“…In the present study rumen pH values did not vary significantly (on average 6.5 ± 0.05) among treatments. Similar results have been reported elsewhere, with average pH values of 6.6 ± 0.2 at CT concentrations of <2% [40][41][42]47]. This result could be explained by the proportion of forage in the rations of the above mentioned studies, which was kept at above >50% of DM.…”

“…Digestibility of CP was significantly higher for treatments 2 and 3 relative to treatment 0 (Table 2). Similar results have been found for doses of 0.83%, 1.37%, and 1.89% CT [47]. Results suggest that there were effective bonds between dietary proteins and CT in the rumen and consequently the intestinal absorption of protein was increased [37,43].…”

“…In this study, CT from DLL did not affect rumen fermentation with regard to total VFA concentration, molar proportions of propionate (C 3 ), butyrate (C 4 ), and the acetate to propionate ratio C 2 :C 3 . These results are in accordance with other studies [40][41][42], all of them at doses ≤2% CT. On the other hand, they differ from results showing a reduction in total VFA concentration [8], C 2 [8], C 4 [47], and C 2 :C 3 ratio [8,47]. Furthermore, increments of C 3 [47] have been reported.…”

“…These results are in accordance with other studies [40][41][42], all of them at doses ≤2% CT. On the other hand, they differ from results showing a reduction in total VFA concentration [8], C 2 [8], C 4 [47], and C 2 :C 3 ratio [8,47]. Furthermore, increments of C 3 [47] have been reported. The difference of effects on rumen fermentation might be related to the doses and ability of CT in forming complexes with dietary proteins, inhibition of catalytic activity of extracellular enzymes, or the reduction of bacterial populations [17].…”