Mechanism And Effect Of Arginine Or NCG On Doe Reproductive Performance And Growth Performance,Ability Of Antioxidant And Anti-stress And Immunity In Young Rabbit

Arginine is the precursor material of nitric oxide(NO),polyamine and creatine.It can directly promote the growth of vascular endothelium,improve animal fertility and growth performance,the body's metabolic capacity and immunity etc.However,the addition of exogenous arginine easily antagonise with antagonize lysine,tryptophan and histidine,which leads to the low utilization of arginine.And arginine is so expensive that limits it applied in production.N-carbamoylglutamic acid(NCG)is a structural analogue of N-acetylglutamic acid(NAG),which synthesizes endogenous arginine by activating carbamoyl phosphate synthetase I and plays similar biological actions.And NCG with low price,adding a little NCG can exert an effect function.NCG has been substitute for arginine in animal(pig,poultry)husbandry industry.However,there are few reports about the application research of Rex Rabbit.So this study was conducted to explore the effects of arginine or NCG on the rex does fertility and the growth performance,antioxidant status,anti-stress ability and immune function of weaned rabbits,which aims to provide the a scientific basis for NCG widely applied in rabbit breeding industry.Experiment 1 Effects of arginine or NCG on the reproductive performance of does and the growth performance and serum hormone of weaned rabbitsThe trial consisted of two parts:the group of lactation does and the young rabbits.A total of 45 lactation does with similar weight were divided into 5 groups with 3 replicates per group and 3 rabbits per replicate.The control group was fed with basal diet,experiment group ? to ? diets were basal diet with adding 0.3%,0.6%Arg and 0.03%,0.06%NCG,respectively.The trial lasted for 35 days.While the young rabbits were choosen from weaned rabbits.A total of 100 young rabbits with similar weight were randomly divided into 5 dietary treatments with 5 replicates per group and 4 rabbits per replicate.The each group diet was the same as does'.The trial lasted for 21 days.The results showed that:1)The does' weight loss was the most in control group,but the does' weight was increased in group ? and ?.The pregnancy rate of group ? was the best.In 21 d and 35 d,the body weight of sucking rabbits in group ? and ? was significantly higher than that in control group.2)Growth hormone(GH)and insulin(INS)of serum levels in group ? and ? were slightly higher than that in control group of 36 d(1 d after weaned rabbits from the does'group)rabbits.3)In young rabbit trial,the finial weight of each treatment group was higher than that in control group,especially the weight increase was more significantly in group ???.The average daily gain(ADG)of each treatment group was significantly increased compared with control group.The average daily feed intake(ADFI)and ratios of feed to gain(F/G)of group ? and ? were significantly lowered compared with control group.GH and INS of serum levels in group ? and IV were slightly higher than that in control group.However the levels of insulin-like growth factor-1(IGF-1)in group ? and ? were significantly higher than those in group ??? and the control group.It was concluded that arginine or NCG can improve the does' fertility and the weaned rabbits' ADG,and the best effcts were observed in 0.6%arginine and 0.06%NCG groups.0.6%arginine and 0.06%NCG could increase the serum levels of GH and INS in young rabbits in different degrees,and significantly increased the serum level of IGF-1 in 56 d rabbits.Experiment 2 Effects of arginine or NCG on NO,iNOS and intestinal structure in young rabbitsExperiment design is same as the experiment 1.The blood samples and jejunum were collected from 1 d after weaned rabbits(36 d rabbits)and 21 d after weaned rabbits(56 d rabbits).These samples are used for analysis of the body NO and iNOS and intestinal structure.The results showed that:1)For 36 d rabbits,jejunum villus height,NO concentration and iNOS activity in each treatment group were significantly higher than those in the control group.Jejunum crypt depths in group ? and ? were significantly lower than that in other treatment and the control groups.NO level of jejunum in each treatment group was higher than that in the control group in different levels.The activities and mRNA levels of iNOS in jejunums in treatment group ? and ? were significantly higher than those in the control group.2)For 56 d rabbits,jejunum villus heights in group? and ? were significantly higher than those in ??? and control groups.The jejunum crypt depth in each treatment group was significantly lower than that in the control group.NO concentration and iNOS activity of serum in group IV were significantly higher than those in the control group.NO concentration of jejunum in group ? was significantly higher than that in the control group.The activities and mRNA levels of iNOS in jejunums in treatment group ? and ? were significantly higher than those in the control group.It was concluded that arginine or NCG can improve jejunum villus height,serum NO concentration and serum iNOS activity of 36 d rabbits,while reduce the jejunum crypt depth of 56 d rabbits.0.6%arginine and 0.06%NCG all significantly increased villus height,iNOS activity and mRNA level in young rabbits' jejunum.Experiment 3 Effects of arginine or NCG on antioxidant capacity and antistress ability in young rabbitsIn this paper,the effects of arginine or NCG on T-AOC,SOD,GSH-Px,MDA,Cort and HSP70 were evaluated.The results showed that:1)For 36 d rabbits,serum SOD activity in each treatment group was slightly higher than that in control group.Cort concentration in group ?,? and ? were significantly lower than that in the control group.The concentration and mRNA expression of HSP70 in group ? and ? were significantly higher than those in control group.2)For 56 d rabbits,SOD activity in group ? and ?was significantly higher than that in control group.Compared with control group,serum Cort concentration in each treatment group were decreased in different degrees,and the contents of group ? and ? were the lowest.HSP70 level of jejunum in each experiment group were slightly higher than that in control group.The mRNA expression level of HSP70 in jejunum of test group ? and ? was significantly higher than that in control group.It was concluded that arginine or NCG can improve serum SOD activity and serum corticosterone level in different degrees in young rabbits.0.6%arginine and 0.06%NCG could increase the concentration and mRNA level in jejunum in different degrees.Experiment 4 Effects of Arginine or NCG Acid on Immune Function in young rabbitsExperiment design is same as the experiment 1.This study was conducted to mainly estimate the effects of arginine or NCG on immune indexes such as immunoglobulin and cytokine of rabbit.The results showed that:1)For 36 d rabbits,serum IgA levels in group?,? and ? were higher than that in the control group.Serum IgM levels in group ? and? were slightly higher than that in the control group.Serum IL-2 concentration in group? was slightly higher than that in the control group.The numbers of CD8+ T lymphocytes in each treatment group slightly increased.Especially in the group II and IV,the numbers of CD8+ T lymphocytes were maximum.The contentrations of SIgA,IL-2 and IFN-? of jejunum in each treatment group were slightly higher than those in the control group.Compared with the control group,the mRNA levels of IL-2,IFN-? and IL-1? increased in each treatment group in different degrees.The jejunum IL-1? protein expression levels in treatment group ??? and ? were significantly higher than those in the control group.2)For 56 d rabbits,serum IgA and IgM levels in each treatment group were significantly increased when compared with the control group.Serum IgG levels in treatment group ?and ? were significantly higher than those in the control group and other treatment groups.Serum IL-1? levels in group ? and ? were significantly higher than that in the control group.The serum IFN-? and IL-2 levels in each treatment group were higher than those in the control group in different degrees.Compared with the control group,there was an increase trend in CD8+ T lymphocyte in each treatment group,especially in the group ?and ?.The contentrations of SIgA,IL-2 and IFN-? of jejunum in each treatment group were slightly higher than those in the control group.Each treatment group has significant increase in jejunum IL-2 mRNA level when compared with control group.Group ? and ?have significant increases in IL-1? mRNA levels compared with the control group.IL-1?protein expression levels in group II and IV were significantly higher than those in other treatment groups and control group.It was concluded that arginine or NCG can improve the IL-2,IFN-? and IL-1? mRNA levels and the IL-1? protein expression level in jejunums of 36 d rabbits in different degrees.Arginine or NCG can significantly increase the serum IgG?IgA and IgM concentrations and the jejunum IL-2 mRNA level of 56 d rabbits.0.6%arginine and 0.06%NCG can significantly increase jejunum IL-1? mRNA level and its'protein expression in young rabbits.It can be seen that 0.6%arginine and 0.06%NCG had the best effect on the immune indexes of young rabbits.