Abstract

GALINDO, Juana et al. Modulator effect of Leucaena leucocephala on the rumen microbiota. Zootecnia Trop. [online]. 2008, vol.26, n.3, pp.249-252. ISSN 0798-7269.

With the objective to evaluate the modulator effect of Leucaena leucocephala on the methanogenic bacteria and other microbial groups in the rumen was conducted a trial according to a completely randomized design in a factorial arrangement (4 x 4, four leucaena proportions and four times of fermentation), under in vitro conditions. The trial consisted of four star grass (Cynodon nlemfuensis) with leucaena ratios, which were: treatment A=100:0, B=80:20, C=75:25, and D=70:30. The sampling was performed before the incubation (0 hour), and at 4, 8, and 12 h of fermentation. The counts of methanogenic bacteria were 40.22, 38.42, 13.98, and 12.46 x 107 cfu/mL for the treatments A, B, C, and D, respectively. The modulator increased the population of cellulolytic bacteria, compared with the control without supplement, and the best response was found in the ratios 80:20 and 70:30. The populations of cellulolytic fungi were 2.08, 3.49, 3.69, and 4.48 x 103 tfu/mL for A, B, C, and D treatments, respectively. The protoozoa population varied from 1.50 to 2.75 x 105 cell/mL, under the trial conditions. In all cases with L. leucocephala as modulator the populations were significantly small, but the smallest was found when the ratio 80:20 of star grass:modulator was used. It is concluded that the modulator from the fermentation with L. leucocephala is suitable for reducing the population of rumen methanogenic bacteria without affecting the total population of cellulolytic bacteria.

Keywords : rumen; methanogenic; cellulolytic bacteria; fungi; modulator.

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