The effects of improving low dietary protein utilization on the proteome of lamb tissues

Abstract

Cistus ladanifer L. is a common shrub endemic to the Mediterranean region with high levels of condensed tannins (CT). CT form complexes with dietary protein resisting microbial degradation in the rumen, which enhances dietary protein utilization in ruminant diets. The objective of this study was to evaluate the utilization of CT in the diet of lambs on the proteomes of muscle, hepatic and adipose tissues. Twenty-four Merino Branco ram lambs were randomly allocated to three treatments (n = 8): C – control (160 g crude protein (CP)) per kg DM, RP – reduced protein (120 g CP/kg DM); and RPCT – reduced protein (120 g CP/kg DM) treated with CT extract. At the end of the trial, lambs were slaughtered and the longissimus lumborum muscle, hepatic and peri-renal adipose tissues sampled. A two-way approach was used for proteomic analysis: 2D-DIGE and nanoLC-MS. In the muscle, C lambs had lower abundance proteins that partake in the glycolysis pathway than the lambs of other treatments. Control lambs had lower abundance of Fe-carrying proteins in the hepatic tissue than RP and RPCT lambs. The latter lambs had highest abundance of hepatic flavin reductase. In the adipose tissue, C lambs had lowest abundance of fatty-acid synthase