Plasma free amino acid profiles of Boer goat bucks as influenced by two feeding regimens

Abstract

The aim of the study was to monitor the physiological changes in plasma free amino acid profiles in Boer goats under nutritional restriction. Fifteen Boer goat bucks were allocated to two experimental groups: CG (control), fed Themeda trianda hay, supplemented with maize, molasses and urea ad libitum; and RG (restricted feeding) fed the same hay (80 and 86% of the daily NRC energy and protein requirements, respectively) for 29 days. Animals were weighed and blood collected weekly for determination of plasma free amino acid profiles and the results compared between experimental groups. At the end of the experimental period the CG animals had higher concentrations of alanine, tyrosine and citrulline amino acids. The RG group had higher concentrations of valine, isoleucine, leucine, threonine, methionine, lysine, taurine, ornithine, hydroxyproline and tri-methyl-histidine, while glycine, serine, aspartic acid, glutamic acid, arginine, histidine and proline levels were similar in both groups. From the results it can be concluded that plasma amino acid profiles in the Boer goat were significantly affected by nutritional restriction. The degradation of short carbon chain amino acids is preferred to long carbon chain amino acids for gluconeogenesis in the physiological mechanisms of response to nutritional restriction in Boer goats.

Keywords: Boer goat; nutrition; restricted feeding; amino acids

South African Journal of Animal Science Vol. 36 (5) 2006: pp.14-17