Isolation and characterization of actinomycetes from healthy goat faeces

Abstract

To isolate and characterize actinomycetes with probiotic activities from healthy goat faeces. Faecal actinomycetes were isolated by dilution methods and identified by 16S rRNA gene sequence analysis. The hydrolytic enzyme activities were analysed by clear zone formation. The antimicrobial activities and resistance to heavy metals were tested by growth inhibition methods. The isolates belong to a small group of actinobacterial genera, including Streptomyces, Nocardiopsis and Oerskovia. The Oerskovia was the most widely distributed genus among the cultures. The proportion of streptomycete-like strains producing amylase or protease is significantly higher than those of other actinomycetes (P < 0.05). Compared with streptomycete-like strains, a higher proportion of (alpha- or beta-) galactase-producing other actinomycetes was found in goat faeces. More than 50% of streptomycete-like strains showed activities against test fungi. Streptomycetes could tolerate 0.25 mmol l(-1) Cr(2)O(7)(2-), 2 mmol l(-1) Ni(2+); however, other actinomycetes are liable to 40 mmol l(-1) Fe(3+) and 0.25 mmol l(-1) Cr(2)O(7)(2-) and resistant to 5 mmol l(-1) Ni(2+) and 2 mmol l(-1) Cu(2+). The different physiological characteristics of the actinomycetes suggested that the cooperation in the actinomycetes might be involved in their association with goat. Probiotic mixtures based on faecal actinomycetes showed potentials in animal production.