Effects of Replacing Fish Meal and Part of Soybean Meal with Enzymatically Hydrolyzed Soybean Meal on Growth Performance, Diarrhea Incidence, and Intestinal Health in Weaned Piglets

The aim of this study was to evaluate the effects of substituting fish meal and part of soybean meal with enzymatically hydrolyzed soybean meal (EHSM) on growth performance, diarrhea incidence, antioxidant and immune status, and intestinal health in weaned piglets. Eighty 25-day-old piglets were distributed into two treatments with 8 replicate pens of 5 piglets each and fed a control diet or an EHSM diet for 42 days, with EHSM completely replacing fish meal and partially replacing soybean meal at inclusion levels of 9% and 4% during the pre-starter and starter phases, respectively. Compared with controls, EHSM increased day-42 body weight, average daily gain during days 28–42 and overall, and decreased feed conversion ratio during days 0–14 (p < 0.05). EHSM also reduced diarrhea incidence during days 0–14 (p = 0.050), decreased jejunal crypt depth, elevated jejunal villus height-to-crypt depth ratio, and increased NQO1 mRNA expression (p < 0.05). Plasma antioxidant and immunoglobulin indices were unaffected. Overall, EHSM improved growth and intestinal health, supporting its use as an alternative protein ingredient in weaned piglet diets. Additional research is warranted to clarify how EHSM influences intestinal function in weaned piglets.