Protein and amino acid requirements of the growing-furring blue fox ( Alopex lagopus ).

Abstract

Abstract The established official protein recommendations for the blue fox are based on the amount of digestible protein without consideration of the amino acid content of the feed. Recent research with blue foxes has thrown light on the amino acid requirements of this species, thus allowing for more precise definition of nutritional requirements. According to current knowledge, the established protein recommendations are unnecessarily high and could well be lowered without compromising the welfare and performance of the animal. This would be beneficial for the environment in terms of reduced nitrogen emissions. Furthermore, this would contribute to considerable savings in feed costs. Summarizing the present data, a protein level of 20-22% of metabolizable energy (ME) in diets rich in sulphur-containing amino acids seems adequate for the growing-furring blue fox. Even lower levels (15-16% protein of ME) may ensure normal growth, especially during the later phases of the growing period, as well as normal hair priming. Methionine is the first limiting amino acid in conventional diets that are primarily based on slaughter by-products. Special attention in practical feed formulation should thus be paid to the provision of adequate methionine in the diets for the growing-furring blue fox.