Effect of lactic acid bacteria administered as feed supplement on the weight gain and ruminal pH in two South African goat breeds

Abstract

Antibiotics as growth promoters are banned in most European countries, because of antibiotic resistance and residues in animal products, and the release of recalcitrant antibiotics into the environment. Probiotics are the preferred alternative, because of no harmful attributes when compared to antibiotics, and the additional advantage of the ability to stabilise the microbial communities in the gut. We investigated the effects of LAB on the growth performance of South African goats. Randomly selected 17 Specked and 18 Boer goats were divided into five treatment groups according to sex and breed and were placed in an experimental trial for 30 days. Ruminal fluid was collected before and after the trial to monitor the changes in the pH. Data collected were analysed using a one-way analysis of variance (ANOVA) (SAS, version 9.4). Results revealed that LAB supplementation had no effect on feed intake in all experimental groups. However, the average weight gain was higher in the LAB groups when compared to other groups. Sex and breed had effects on final body weight; that is male (18.4 kg) goats are heavier than females (15.3 kg) averagely, irrespective of the breed, and the Boer goats are heavier than Specked irrespective of gender. The pH decreased averagely from 7.01 to 6.33 across all treatments, confirming the modulatory effect of the administered lactic acid bacteria. The findings in this study suggested that LAB as probiotics may induce beneficial effects in goats by enhancing weight gain, dropping the gut pH, thus maintaining an equilibrium of ruminal microbiota.