Effects Of Dietary Cysteine Level On Growth Performance,Nitrogen Metabolism And KAP6.1Gene MRNA Temporal And Spatial Expression Of Rex Rabbit

This experiment was conducted to investigate the effects of dietary Cysteine level on growth performance, nitrogen metabolism, fur quality and KAP6.1gene mRNA temporal expression of Rex rabbit. One hundred and twenty healthy90-days-old Rex Rabbits were divided randomly into four equal groups with thirty replicates in each group and each replicate contained one rabbit. Control group was fed the basal diet, and the experimental group fed basal diet added the cysteine rates of0.25%、0.35%、0.45%respectively.The experiment included a pretrial period of7days and an experimental period of40days. The results showed as follows:The final weight (FW) in the groups with the diets containing0.25%and0.45%cysteine was significantly higher than that in the groups with the diets containing0%and0.35%cysteine (P<0.05),but had no significant influence on average daily gain (ADG) and feed/gain (F/G)(P>0.05). The nitrogen intake, digestible nitrogen in the groups with the diets containing0.35%cysteine was dramatically significantly higher than the other groups (P<0.01),nitrogen retention in the groups with the diets containing0.35%cysteine was higher than that in the groups with the diets containing0%cysteine (P<0.05), but had no significant influence on fecal nitrogen output, urine nitrogen output, nitrogen apparent digestibility, nitrogen utilization rate and biological value of nitrogen (P>0.05). After forty days feeding with cysteine contained diet Fortieth day, the area of fresh pelt in the groups with the diets containing0.45%cysteine was significantly higher than the other groups (P<0.05). After forty days feeding with cysteine contained diet, the hair density in the groups with the diets containing0.45%cysteine was significantly higher than that in the groups with the diets containing0%cysteine(P<0.05),but had no significant influence on thickness of fresh of pelt (P>0.05). After twenty days feeding with the diet containing 0.45%cysteine, gene expression level in the cartilage, skin of KAP6.1was dramatically significantly higher than the other groups (P<0.01),but had no significant influence after ten, thirty, forty days feeding with cysteine contained diet (P>0.01). Considering all indices of this experiment, the appropriate Cysteine levels in the diet of rex rabbits are0.45%,and feeding with cysteine contained diet during110to120days-old will be the best.