Effect of lactic acid bacteria preparations on calf fecal flora

- This experiment was conducted to investigate the effects of lactic acid bacteria preparations on microbial diversity and community structure of calves. On days 1 and 7 of the trial period, feces were collected into sterile tubes and labeled (Day 1: control group D1DZ, experimental group D1SY, and Day 7: control group D7DZ, experimental group D7SY). Twenty Angus calves (150±10 kg) were selected and randomly divided into two groups of 10 calves each. The control group fed a basal diet. In addition to feeding the basal diet, the experimental group was given 15 mL lactobacillus preparation orally at 09:00 and 16:00 h every day. Calves were allowed free feeding and drinking water. All other feeding environments and management conditions remained consistent with the experiment lasting for seven days. At the end of the experiment, the fecal microflora of the calves was analyzed using 16S rRNA sequencing techniques. The 16S rRNA analysis data were processed using the Excel 2007 software and analyzed by the IBM SPSS statistical software (Statistical Analysis System, version 22). The Alpha diversity index analysis showed that the Chao and the Ace indices were significantly different after feeding supplemented with lactic acid bacteria. The PCA analysis showed that the fecal flora structure differed significantly after supplementation with the lactic acid bacteria preparation. Further analysis showed that the lactic acid bacteria increased Firmicutes, Patescibacteria, Rikenellaceae_RC9_gut_group, Clostridium_ sensu_stricto_1, and prevotellaceae_UCG-003 in the feces. Therefore, we speculate that lactic acid bacteria preparations play an important role in animal production and are beneficial to the diversity of the fecal microflora of the calves.