Effects of Dietary Supplement of Methionine and Lysine on Blood Parameters and Fur Quality in Mink Fed with Low-protein Diets

Abstract

Four groups of mink were fed from weaning to pelting with feed of two different protein levels. The metabolizable energy (ME) from protein amounted to 40/36% in the control group and 25/20% in the three low-protein groups during the early and late growth period, respectively. One of the low-protein groups received an unsupplemented diet, the second diet was supplemented with methionine, and the third with methionine and lysine. The levels of methionine and lysine added in the low-protein feeds were equivalent to the control diet. In all low-protein groups the decreased protein intake was observed as increased nitrogen retention in young animals and as elevated plasma levels of alanine and branched chain amino acids (BCAA) valine, leucine and isoleucine. The clinical blood parameters either remained unchanged or some improvement was observed in the low-protein groups compared to the control group. The low-protein diets were sufficient for growth and gave larger pelts than the control diet, but the quality of the pelts was significantly reduced as compared to the control group given a normal protein diet. The dietary supplementation of methionine and lysine yielded no improvement in the fur quality as compared to the unsupplemented low-protein feed.