Effects of Dietary Methionine Level on Nutrient Digestibility,Nitrogen Metabolism and Serum Biochemical Parameters of Female Blue Foxes in Prepare Breeding Period

This experiment was conducted to study the effects of dietary methionine level on nutrient digestibility,nitrogen metabolism and serum biochemical parameters of female blue foxes in prepare breeding period.One hundred and fifty healthy female blue foxes were randomly assigned into 5groups with 30 replicates per group and 1fox per replicate.The blue foxes in groupsⅠtoⅤ were fed basal diet supplemented with 0,0.26%,0.52%,0.78% and 1.04% methionine,respectively.The pre-test lasted for 7days and the trial lasted for 60 days.The results showed as follows:1)the digestibility of dry matter and crude fat were found no significant difference among all groups(P0.05).The digestibility of crude protein in group Ⅲ was significantly higher than that in groupsⅠ and Ⅱ(P0.05).2)The nitrogen intake content of each group was found no significant difference among all groups(P0.05).The fecal nitrogen content in groupⅤ was significantly lower than that in groupⅡ(P0.05),and the urine nitrogen content in groupⅢ andⅤ was significantly higher than that in groupⅡ(P0.05).The nitrogen deposition content in group Ⅳ was significantly higher than that in groupsⅠ and Ⅱ(P0.01),the nitrogen deposition content in groupⅢandⅤ was significantly higher than in groupsⅠandⅡ(P0.05).3)The mostly amino acid apparent digestibility increased with the increasing of dietary methionine level.The serum alanine aminotransferase activity in groupsⅢandⅣ were significantly higher than that in group Ⅰ(P0.05).The serum total protein content in group Ⅲ was significantly higher than in group Ⅰ(P0.05),but the content of albumin and globulin in serum had no significant difference among all groups(P0.05).In conclusion,when 0.52% methionine is supplemented in the protein diet with 29.31% protein level,that is,when the dietary methionine level is 1.03%,the female blue foxes have the optimum nutrient digestibility and serum biochemical parameters and meet the demand of methionine.