Counts of ruminal fibrolytic bacteria in Creole goat of Mendoza, Argentina

GRILLI, D.; PAEZ, S.; EGEA, V.; CERON, M; COBOS, E; ALLEGRETTI, L.; ARENAS, N.

BIOCELL

INST HISTOL EMBRIOL-CONICET

Año: 2010 vol. 34 p. 50 - 50

0327-9545

In Lavalle, Mendoza, goats consume a high proportion of shrub species, which represent a large supply of fiber. The digestibility of dry matter and fiber (cellulose, hemicellulose and lignin) of goat breeds adapted to arid areas is higher than that of other races and domestic ruminants. A high efficiency in use of fiber may be due to a large concentration of fibrolytic bacteria on food particles present in the rumen. The aim of this study was to quantify the ruminal fibrolytic microbiota in Creole goats in two seasons. Rumen samples were taken from a cannulated goat grazing on natural grassland in the summer (wet season) and winter (dry season). Cellulolytic, hemicellulolytic and pectinolytic bacteria were quantified by most probable number method. Bacterial counts were submitted to logarithmic transformation before performing ANOVA (Tukey test). Concentrations of cellulolytic, hemicellulolytic and pectinolytic bacteria were significantly higher in summer (0.08325x109, 7 x1010 and 7x1010 bacteria.mL-1, respectively) than in winter (0.0035x109, 0.01725x1010 and 0.585x1010 bacteria mL-1, respectively). Lignin affects fibrolytic bacteria count, because it inhibits the hydrolysis and utilization of carbohydrates by bacteria in the rumen. Higher counts observed during summer may arise because the goats selected shoots of shrubs with lower lignin content in the wet season. Further work should assess the relationship between the nutritional composition of diet and fibrolytic rumen microbiota.