Effect of Volatile Fatty Acid Infusion on Development of the Rumen Epithelium in Neonatal Sheep

The purpose of this study was to determine whether the continuous intraruminal infusion of calculated physiological concentrations of volatile fatty acids (VFA) stimulated the metabolic development of the neonatal rumen. Eight 1-wk-old lambs were assigned to one of three treatments: saline infusion (three lambs), VFA infusion (three lambs), or no infusion (two lambs). Rumen catheters were surgically implanted into lambs in the infusion groups. The amount of VFA infused, beginning at 2 wk of age, increased weekly in equal increments of 12.5% of the estimated net energy requirement until, at 6 wk of age, lambs received 50% of their estimated net energy requirement from the infused VFA. All lambs consumed milk replacer for ad libitum intake and had free access to water. The lambs that were infused with VFA tended to have longer rumen papillae. There were no differences in width or number of papillae per square centimeter across treatments. Rumen epithelial cells isolated from lambs that were infused with VFA tended to oxidize less glucose and produce more acetoacetate than did cells from lambs that were infused with saline or from uninfused lambs. β-Hydroxybutyrate production by isolated rumen epithelial cells and concentrations of blood glucose, acetoacetate, and β-hydroxybutyrate were not different among the three treatments. Thus, infusion of physiological concentrations of VFA appears to stimulate some aspects of rumen metabolic development.