Evaluation of Lactobacillus and Bacillus-based probiotics as alternatives to antibiotics in enteric microbial challenged weaned piglets

The present study investigates the efficacies of two probiotic products as alternative to antibiotics on growth performance, nutrient digestibility, immunity, and fecal microbiota in piglets challenged with Salmonella enterica serovar Typhimurium KCTC 2515 and Escherichia coli KCTC 2571. Ninety-six 28-day-old piglets were randomly allotted to four dietary treatments consisting of four replicate pens with six piglets each. The dietary treatments were: negative control (NC), positive control (PC, 0.002% apramycin), 0.5% Lactobacillus probiotic (P1), and 0.04% Bacillus probiotic (P2). Average daily gain (ADG) and average daily feed intake (ADFI) were improved by treatment with PC and P1, whereas, feed conversion ratio (FCR) was improved by treatment with P2 compared to NC (P < 0.05). Digestibility of dry matter, crude protein, and crude fat increased upon treatment with PC, P1, and P2 compared to NC. All dietary treatments showed significant reduction of fecal Salmonella and E. coli counts with an increase of Lactobacillus and Bacillus spp counts compared to NC (P < 0.05). The serum IgG level was elevated by P2 treatment compared to others (P < 0.05). Overall, both Lactobacillus and Bacillus probiotics had beneficial effects on weaned piglets under challenged condition and therefore, can be used as potential alternatives to antibiotics.   Key words: Lactobacillus, Bacillus, fecal microbiota, immunoglobulin, challenged piglet.