Effect of Samanea saman (Jacq.) Merr., Albizia lebbeck Benth and Tithonia diversifolia (Hemsl.) Gray (plant material 23) on the methanogen population and on the ruminal microbial ecology.

An experiment with completely randomized design in factorial arragement (4 x 5) and under in vitro conditions was conducted to assess the effect of Samanea saman, Albizia lebbeck and Tithonia diversifolia, plant material 23, on the methanogen population and on the ruminal microbial ecology. Four treatments were compared: A) Cynodon nlemfuensis (star grass, control), B) Samanea saman (carob tree), C) Albizia lebbeck (albizia) and D) Tithonia diversifolia, plant material 23 (tithonia). The samplings were conducted before incubation (hour 0), at 4, 8,12 and 24 h after the beginning of fermentation. They were replicated four times in time. There was no effect of the foliage trees on the population of total viable bacteria of the rumen. The methanogen populations, in the fermentation up to 8 h, were 70, 34, 19 and 18.5 x 109 ufc mL-1 for star grass, carob tree, and tithonia, respectively. The highest population of cellulolytic bacteria was found in albizia, while the cellulolytic fungi, at 8 h of fermentation, had the highest population with this same plant. The protozoa population was 8.9, 7.2, 6.0 and 6.5 x 105 cells mL-1 for the treatments A, B, C and D, respectively. No effects on the pH or on the ammonium concentration in the rumen were found. It is concluded that carob tree, albizia and tithonia reduce the methanogen population and have beneficial effects on the ruminal microbial ecology when modifying the populations of protozoa, bacteria and cellulolytic fungi. [ABSTRACT FROM AUTHOR]