Canola meal or soybean meal as protein source and the effect of microencapsulated sodium butyrate supplementation in calf starter mixture. II. Development of the gastrointestinal tract

The aim of this study was to assess the effect protein source, either soybean meal (SM) or canola (CM), and microencapsulated sodium butyrate (MSB) supplementation in a pelleted starter mixture on development gastrointestinal tract (GIT) dairy calves. Twenty-eight bull calves (8.7 ± 0.8 d age 43.0 4.4 kg; mean SD) were assigned 1 4 treatments 2 × factorial arrangement: CM as main source without with MSB SM MSB. Calves fed starters ad libitum exposed gradual weaning program, taking place 51.7 age. observed for an additional 3 wk after slaughtered 72.1 0.9 age, which GIT dissected. Morphometric measurements recorded, samples determination ruminal fermentation, histology, gene expression, brush border enzyme activities collected. Canola use increased abomasal tissue weight, jejunal weight length, mRNA expression SLC16A4 (formerly known MCT4) FFAR2 (GPR43) epithelium, decreased ammonia SLC15A2 (PEPT2) SLC6A14 (ATB0+) proximal small intestine ileum, respectively. However, inclusion papillae epithelial surface, epithelium dry while increasing SLC16A1 (MCT1) epithelia. Reduced surface area associated most apparent when combined mixture. Additionally, thickness omasal living strata, stratum corneum, duodenal ileal aminopeptidase A enzymatic activity N activity. Overall, might increase growth calves, particularly intestine, but may negatively affect intestinal function peptide AA absorption. Supplementation has negative development, CM.