3-methylhistidine as an Indicator for Protein Beakdown: An Experimental Model in Male Capra hircu

Abstract

The role of the amino acid 3-methylhistidine as an indicator of protein breakdown and weight loss is  often suggested. Despite existing information for other animal species, little is known about the actual  levels of 3-methyhistidine in the serum of less studied domestic species such as the goat. We have  evaluated the 3-methyhistidine serum concentrations in young Boer goat bucks subjected to two distinct  feeding regimens: winter-grass hay with or without supplementation. Non-supplemented animals had a  negative nitrogen balance and experienced weight loss throughout the experiment and significantly higher  concentrations of 3-methyhistidine than supplemented animals that had a slight increase in live weight.  This amino acid can be considered a valid indicator of protein breakdown and weight decrease in male  goats. Serum 3-methylhistidine concentrations in adequately fed male goats were similar throughout the  assay (20-40 μmol/l) whereas in weight-losing animals, concentrations of up to 170μmol/l can be expected.