Growth and intestinal histomorphology of piglets fed infant formulas containing intact or hydroly/ed soy proteins

Hydrolyzed casein is commonly used in formulas for infants intolerant to intact cow milk or soy proteins. Efficacy of formulas with hydrolyzed soy proteins has not been fully determined. We have previously shown that acute metabolic responses of piglets fed formulas containing hydrolyzed vs. intact soy protein are similar. Our objective was to determine effects of casein/whey (CW), intact soy protein (SI) or hydrolyzed soy protein (SH) on growth and intestinal histological and inflammatory responses. Piglets (n=10, age=2 d) were acclimated for 5 d to pig milk replacer, and were then randomly allotted to one of three diets (d 0). Piglets were weighed daily and jejuna! tissue samples were collected on d 0, 2, 5, and 10. Average daily gain (ADG) was greater for CW piglets (121 g/d) than piglets fed soy ( 109 and 85 g/d for SH and SI, respectively; P < 0.05). ADG of SH piglets was greater than SI piglets (P < 0.06). On d 2, villus height was greater in CW piglets compared to those fed soy (P < 0.05). Crypt depth was greater on d 5 and 10 compared to d 0 (P < 0.05) and was not influenced by diet. Regardless of diet, number of mast cells decreased through d 5 and returned to dO numbers by d 10. Goblet cell numbers were not influenced by age or diet. CW promoted greater weight gain and resulted in less morphological damage than SH or SI; however, no differences in intestinal histomorphology were detected between SI- and SH-fed piglets. The growth responses to SH formulas indicate that these may be a viable alternative to milk protein-based and intact soy-protein based infant formulas in cases of allergy or intolerance.