| Effects of different levels of methionine supplementation on diet digestibility,production performance,blood biochemical indexes and the intestinal tissue of minkwith melatonin implantation were investigated.Optimum amount of additionalmethionine to the diet was determined,and feed formulation for the mink withmelatonin during the growth period and winter fur growth period was screened out.The nutritional requirements of amino acids in mink were estimated to provide thedata for feed application in animal husbandry.The most suitable methionine level ofmink in this period was determined to provide a theoretical basis for the mink farming,and to improve economic benefits.There were three experiments in this studyExperiment1:The effect of different levels of methionine on nutrient digestibility and serumbiochemical indexes in young minks was studied in Dalin Mingwei Mink LimitedCorporation, from July15,2012to October20,2012.Eighty healthy weaned youngAmerican short-haired-black minks with similar weight were selected and randomlydivided into4groups of20with10males and10females, respectively.All the minkswere pretreated with melatonin.One group was fed basal diet(group A)and othergroups were fed basal diet supplemented with0.2,0.4and0.6%methionine (GrourpsB,C and D)respectively.The results were as follows:(1)Nutrient digestibility in140d male minks fed0.2%methionine were significant hi-gher(P<0.05)than those in other groups.There was no significant effect on nutrients digestibility in female minks among these4groups.(2)Weight gain of mink was significantly increased in diets with methionine addition,in the experimental design,maxium weight gain was obtained when diet added with0.4%methionine.(3)Blood total cholesterol content of mink was reduced with methionine supplementa-tion,in the experimental design,significant effect was recorded when0.4and0.6%ofmethionine were included in mink diets.Experiment2:The effect of different levels of methionine on melatonin implanted female mink performance and blood biochemical indices were studied in Dalian Mingwei minkindustry limited company,from June20,2012to August13,2012.Forty healthy femaleminks were randomly divided into four groups named groups A, B, C and D,and wererespectively fed one of four experimental diets with increasing levels of methionine(Met)at0,0.2,0.4and0.6%,Respectively.The main results were as follows:(1)Dietary nutrient digestibility for female mink with MLT implantation was notaffected during recovery period and winter fur growth period.(2)The appropriate supplementing amount of methionine in diets for female minkwith MLT implantation was0.4%during recovery period and winter fur growthperiodExperiment3:The effect of different levels of methionine on nutrient digestibility and intestinalmucosal structure of mink with melatonin treatment were investigated in DalinMingwei Mink Limited Corporation, from July1to September23,2013.Fourty-eight65-day healthy weaned young American short-haired-black minks with similar weightwere selected and randomly divided into4groups of12with6males and6females,respectively.All the minks were pretreated with melatonin.Minks in one group wasfed a basal diet (Grourp O) and in the other groups,Groups E, F and G were fed basaldiet supplemented with methionine at0.1,0.2and0.3%,respectively.The main results were as follows：(1)Methionine had no significant effect on nutrient digestibility and weight and lengthof pelts(P>0.05).(2)The current study showed that weight gain of male growing mink was significantlyincreased by methionine inclusion with adequate level being at0.3%(P<0.05). |
