Fermented soybean meal (FSBM) has been widely investigated as a nutritional strategy for reducing the use of fish meal (FM) and antibiotic growth promoters. Microbial fermentation by using bacteria can increase the bioavailability of nutrients and reduce the levels of antinutritional factors in soybean meal (SBM). In this study, we evaluated whether FSBM produced from Lactobacillus species and Clostridium butyricum improves growth performance, diarrhea incidence, and fecal bacteria in weaning piglets. Eighty-four crossbred male piglets with an average initial body weight of 8.36±0.63 kg were randomly allotted to 3 dietary treatments consisting of 7 replicate stalls with 4 piglets each. The dietary treatments were: (1) 3% FM in the diet; (2) 5% FSBM in the diet; and (3) 3% FM in the diet plus 4 mg/kg antibiotic growth promoters (AGP). We determined that growth performance was unaffected in FSBM-fed weaning piglets compared with a FM group. Similar to the AGP group, FSBM supplementation significantly reduced diarrhea incidence in weaning piglets. The number of fecal Lactobacillus species significantly increased in 28-day-old FSBM-fed weaning piglets compared with the other groups. Compared with AGP, FSBM has the highest inhibitory effect on the number of fecal Enterobacteriaceae at 28 d old. Furthermore, serum immunoglobulin G and immunoglobulin A levels in FSBM-fed weaning piglets significantly increased at the same age. These results together indicate that FSBM can replace FM in the diets of weaning piglets without affecting growth performance. Furthermore, similar to AGP, FSBM could improve diarrhea incidence, fecal bacteria, and immunoglobulin levels in weaning piglets. Therefore, SBM fermented by Lactobacillus species and C. butyricum demonstrated high potential for development as swine feed ingredients.
