책임운영기관 농촌진흥청 국립축산과학원 (로고)

This study conducted to investigate potential differences in the activity of genes involved in volatile fatty acid (VFA) absorption, pH regulation, and energy metabolism in epithelial cells of forestomach administered either endophyte-infected (E+; 4.45 mg ergovaline/kg) or endophyte-free (E−) tall fescue seed. Twelve steers [body weight (BW) = 547 ± 9 kg] were fed alfalfa cubes at 1.5 × NEm and dosed 1 kg of ground tall fescue seed daily via rumen cannula for 21 days. On day 22, steers were slaughtered, and tissue samples were collected from the rumen, reticulum, omasum, and abomasum. Gene expression analysis revealed that monocarboxylate transporters (MCT), isoform 1 and MCT4 expression levels were significantly lower (p0.05) by seed exposure. These findings suggest that endophyte-infected tall fescue seed may impair ruminal VFA absorption in its dissociated state (pH > 5.8) by downregulating MCT1 and MCT4, along with suppressing NHE2, DRA, and AE2. Therefore, this mechanism may partially explain the reduced weight gain associated with fescue toxicosis in cattle.