Evaluation of Using Fermented Okara (Soybean By-Product) as a Feed Ingredient in Commercial Pig Production

Okara is an insoluble soybean byproduct, and much of it is discarded due to its high perishability. This study investigated the efficacy of fully replacing fermented soybean meal in a control diet (PC) with fermented okara at an equal crude protein level (EC) or at an equal amount level (EQ) on growth performance and meat quality in 315 pigs, starting from weaners to finishers. Results indicated that EC and EQ groups led to significantly (p < 0.05) improved growth performance primarily during the grower and finisher stages. Both EC and EQ groups had significantly (p < 0.05) increased duodenal villus height. Moreover, EC group had significantly (p < 0.05) elevated concentration of acetic acid and reduced branched-chain fatty acids (iso-butyric acid and 2-methylbutyric acid) when compared to PC. There was an increase in volatile fatty acid-producing bacteria at the genus level, such as Prevotella, Lactobacillus, Megasphaera and Streptococcus in EC group. More importantly, no adverse effects on meat quality were observed in pigs fed with fermented okara. Taken together, utilization of fermented okara as an alternative protein source for animals not only improves performance and gut health, but also facilities a recycling economy to promote sustainable agriculture practices.