Effect of Feeding Levels of Microbial Fermented Soy Protein on the Growth Performance, Nutrient Digestibility and Intestinal Morphology in Weaned Piglets

To elucidate the efficacy of different levels of microbial-fermented soy proteins (FSP) on piglet performance, a total of 240 weaned piglets ($L{\times}Y{\times}D$, $22{\pm}3$ d of age, $5.16{\pm}0.07$ kg initial BW) were allotted to 4 treatment diets comprising control, FSP-3%, FSP-6% and FSP-9%. The fermented soybean product named $Pepsoygen^{(R)}$ was utilized for the study. There were 15 pigs per pen and 4 pens per treatment. The control diet contained 15% soybean meal (SBM), and SBM for the treatment diets was replaced at 3, 6 and 9% with FSP, respectively. Experimental diets were fed from 0 to 14 d (phase-I) after weaning and then a common commercial diet was fed from 15 to 35 d (phase-II). There was a linear (p<0.05) increase in ADG and ADFI at both phases of measurement. The feed to gain ratio was also improved, showing a linear (p<0.01) trend as the level of supplementation increased. Except for phosphorus, the digestibility of all other nutrients was improved linearly (p<0.05) in the FSP added diets. However, villous height and crypt depth were not affected by dietary treatments. No special effect on intestinal morphology was noticed between FSP-added and control diets. In conclusion, the growth, digestibility of nutrients and morphological changes in weaned pigs fed FSP showed improved performance at higher levels of supplementation.