Porcine colonic microstructure and function as affected by the feeding of casein and soy protein

Abstract

This study examined the effects of dietary casein and soy protein on the colonic mmcrostructure and function of pigs. Twelve crossbred pigs, 29–43 kg body weight, were fed their respective diets ad libitum for a minimum of 14 days. Gut function was assessed by the in vivo perfusion of two-20 cm segments (proximal and distal) of colon. Following the perfusion period, portions of the proximal and distal colon were collected for analysis of protein content, microstructural examination and mucosal energetics. Feeding casein significantly increased colonic protein and the surface area to mucosal volume ratio of colonic tissues, when compared to soy protein. Mucosal oxygen consumption rate for casein and soy protein were not different, nor were microstructural differences detected between the proximal and distal colonic segments. In vivo colonic perfusion studies indicated statistical differences, by protein source and by colonic segment, for the transport of chloride and the individual fatty acids. Animals fed the soy protein had a greater (P<0.05) net secretion of chloride and absorption of volatile fatty acids.