Effects of dietary supplement of methionine and lysine on blood parameters and fur quality in blue fox during low-protein feeding

Abstract

Four groups of blue fox (Alopex Lagopus) were fed from weaning to pelting with feed of two different protein levels. The metabolizable energy (ME) from protein amounted to 35/30 % in the control group and to 22/18 % in three low-protein groups during the early and late growth period, respectively. One of the low-protein groups received an unsupplemented diet. The second low-protein diet was fortified with methionine, and the third with methionine and lysine to the same level as in the control diet. Hematological values, urea and creatinine were lower in all low-protein groups as compared to the control group. The activities of amino acid metabolizing enzymes ASAT, ALAT and GOT in plasma were lower in the low-protein groups although the relative sizes of the liver and kidneys were greater. The lowered protein content in the feed was sufficient for growth, and only a slight negative effect on fur characteristics was observed. The dietary supplementation of methionine and lysine yielded no improvement in the fur quality or other parameters as compared to the unsupplemented low-protein feed, indicating that there was no deficiency of these amino acids in these low-protein feeds.