Effect of short-term underfeeding on weight of splanchnic organs in ewes.

We assessed the effect of short-term underfeeding on weight and protein mass of splanchnic tissues in adult ewes submitted to a factorial experimental design. In a pre-experimental period, 18 ewes divided into 2 groups of 9 were fed a second cut of natural grassland hay during 4 weeks at 112 or 38% of their energy maintenance requirements. Three ewes of each group were then fed the same hay during 4 weeks at either low (group L), moderate (group M) or high intake (group H), corresponding to 38, 75 or 112% of their energy maintenance requirements, respectively, then slaughtered. Fresh weight and protein mass of splanchnic organs were measured. No carry-over effect of the pre-experimental level of intake on weight and protein mass was observed for any splanchnic organs. Splanchnic tissues contributed at 10.7 and 8.6% to the decrease in live weight for groups M and L, respectively. The decrease in weight of splanchnic tissues (-15%) was mainly attributed to reticulorumen (-23%), liver (-21%), and at a lesser extent small intestine (-11%). No large change in the mass ratio between mucosa and muscular-serosa in both dorsal and ventral sacs occurred in the rumen wall. These results are discussed together with previous published results on long-term underfed ewes, and suggest that the decrease in energy expenditure in whole animal induced by underfeeding is mainly related to the decrease in splanchnic weight at short-term, and to the decrease in other tissues at long-term, splanchnic weight being stabilized.