Effects of Dietary Lysine and Methionine Levels on Growth Performance,Nutrient Digestibility,Serum Biological Parameters and Fur Characteristics of Silver Fox during the Furring Growth Period

This experiment was conducted to study the effects of dietary lysine and methionine levels on growth performance,nutrient digestibility,serum biological parameters and fur characteristics of silver fox during the furring growth period. Seventy 120-day-old male silver foxes with an average body weight of( 5 973 ± 94) g were selected and randomly divided into 7 groups with 10 replicates in each group and 1 silver fox in each replicate. The trial adopt two factor design,in the basal diet,the lysine supplemental levels were 0,0. 50%,and the methionine supplemental levels were 0,0.25%,0.50%,0. 75%,respectively. The contents of lysine and methionine in basal diet were 1.15% and 0.66%,respectively. The experimental period lasted for 51 days. The results showed as follows: 1) dietary lysine and methionine levels had no significant effect on growth performance( P 0.05). 2) Dietary lysine and methionine interaction had no significant effect on nutrient intake,output and digestibility( P 0.05). Dietary lysine level had no significant effect on nutrient intake,protein output and protein digestibility( P 0.05),but had significant effect on dry matter output,dry matter digestibility,fat output and fat digestibility( P 0. 05 or P 0. 01). Dietary methionine level only had significant effect on dry matter output( P 0.05). 3) Dietary lysine and methionine interaction had significant effect on serum total amino acid content( P 0.01),but had no significant effect on the content of total protein,albumin,urea nitrogen and the activities of alanine aminotransferase,aspartate aminotransferase in serum( P 0. 05). Dietary lysine level had significant effect on serum total amino acid content( P 0. 01). Dietary lysine level had significant effect on serum aspartate aminotransferase activity( P 0.01). 4) Dietary lysine and methionine interaction had no significant effect on fur characteristics( P 0.05),and dietary lysine and methionine levels had no significant effect on fur characteristics( P 0.05). In conclusion,considering to reduce feed cost and emission,it is beneficial to production for silver fox in the furring growth period by adding 0.50% lysine( actual lysine content 1.65%) and 0.25% methionine( actual methionine content 0.91%) in basal diet.