Effect Of Adding Leucine And Serine To Corn Dephenolized Cotton Seed Protein Diet On Egg Albumen Quality

The quality of egg albumen is the most concerned part when consumers and traders evaluate the quality of eggs except the eggshell and yolk.It is very susceptible to the influence of dietary protein level and quality because the physiological particularity of laying hens.This study is based on the standard ileum digestible amino acid profile that balanced lysine,methionine,tryptophan and threonine.Leucine and serine are added to low-gossypol cottonseed meal diet,and then to study the effects of leucine and serine on egg albumen quality of peak egg production period and its mechanism.In order to provide a scientific basis for broadening the range of feed protein selection,improving the utilization of cottonseed protein and reducing the dependence on imported soybean meal.Experiment 1,Effects of adding L-leucine to corn-Low-gossypol cottonseed meal diet on performance and egg albumen quality of laying hens.A total of Two hundreds and eighty eight healthy Hy-Line Brown at 28 weeks of age with the similar egg production and body weight were randomly divided into 4 groups with 6replicates per group and 12 layinghens per replicate.All diets were isocaloric(11.11 MJ.Kg-1),isonitrogenous(CP 16.5%)and had the similar standard ileum digestible AA model.hens in control group were fed soybean meal(SBM),Hens in treatment groups were fed low-gossypol cottonseed meal(LCSM),low-gossypol cottonseed meal and Leucine(LCSM+Leu),low-gossypol cottonseed meal and double Leucine(LCSM+2Leu).the experiment lasted 12 weeks.(Result)The results showed as follows: The whole experiment period,Compared to SBM group,at the same time,the feed intake was significantly reduced(P<0.05).The average egg weight of LCSM,LCSM+Leu and LCSM+2Leu groups at 9~12weeks had the trend of decrease compared with the SBM group(P=0.0507).The egg albumen weigh,thick albumen dry matter and albumen protein content of egg in LCSM group,LCSM+Leu group and LCSM+2Leu group were significantly reduced at 12w(P<0.05).The plasma total protein in layinghens of LCSM+2Leu group at 12 w were significant lower than SBM group(P<0.05).The plasma globulin in layinghens of LCSM+Leu group and LCSM+2Leu group at 12 w were significant lower than SBM group(P<0.05).It is concluded that the leucine is not a limiting amino acid in the diet of the peak production laying hens with corn-cottonseed protein.Experiment 2,Effects of adding L-Serine to corn Low-gossypol cottonseed meal diet on performance,egg albumen quality and body health of laying hens.A total of Two hundreds and eighty eight healthy Hy-Line Brown at 28 weeks of age with the similar egg production and body weight were randomly divided into 4 groups with 6replicates per group and 12 layinghens per replicate.All diets were isocaloric(11.11 MJ.Kg-1),isonitrogenous(CP 16.5%)and had the similar standard ileum digestible AA model.Hens in control group were fed soybean meal(SBM),Hens in treatment groups were fed low-gossypol cottonseed meal(LCSM),low-gossypol cottonseed meal with Leucine and Serine(LCSM+Leu+Ser),low-gossypol cottonseed meal with double Leucine and Serine(LCSM+2(Leu+Ser)).The experiment lasted 12 weeks.The results showed as follows:The average egg weight,egg albumen weigh,thick albumen weight,albumen height,thick albumen dry matter and albumen index of the LCSM + Leu + Ser group at 12 W were significantly increased than LCSM group(P<0.05).The eeg weight,thick albumen weight and thick albumen dry matter of LCSM + 2(Leu + Ser)group at 12 w were significantly reduced than LCSM + Leu + Ser group(P<0.05).At 12 W,Compared with the SBM group,the Injury is observed in liver and kidney sections of LSCM group but It can be seen in the LCSM + Leu+ Ser group that the liver cells are uniform in size,The tissue structure is clear;The jejunum villi height,crypt depth and the V / C of the LCSM + Leu + Ser group was similar to the SBM group at 12W(P>0.05);the cilium height and the number of goblet cells of the mucosal gland epithelium of LCSM + Leu + Ser group showed no significant difference(P <0.05).It is concluded that Serine can improve the quality of egg albumen by improving the healthy and maintaining the protein secretion function of the oviduct magnum.Experiment 3,Effects of adding L-Serine to corn Low-gossypol cottonseed meal diet on protein metabolism of laying hens.The trial design was the same as that of experiment 2.The results showed as follows:There was no significant difference in the contents of AST,TP,GLB,and UA in each treatment group at 12W(P> 0.05),The ALT in laying hens of LCSM group at 12 w had the trend of upward(P=0.0523),and the ALB had the trend of decrease than SBM group(P=0.0729);Compared with the SBM group,the LCSM and LCSM + Leu + Ser groups had no significant difference in the m-RNA expression level of TOR,S6k1,4EBP,MuRF1 MAFbX and cathepsin B in the liver and jejunum(P> 0.05).The mRNA expression level of TOR,S6K1,4EBP1,MuRF1 ? MAFbX and Cathepsin B in the Oviduct enlargement of LCSM group showed no significant difference(P>0.05),the mRNA expression level of MuRF1 and MAFbX was numerically higher than SBM and LCSM+Leu+Ser groups.The mRNA expression level of TOR in the LCSM+Leu+Ser group was the highest,which was2.18-fold higher(P < 0.05)than that in the LCSM group.It is concluded that Serine can Promote protein synthesis and Inhibit protein degradation in the Oviduct magnum by increasing the mRNA expression of TOR,MuRF1 and MAFbX genes.In summary,Serine can improve the quality of egg albumen by improving the magnumhealth status,maintaining the protein secretion function and adjusting the protein metabolism of the oviduct magnum in Low-gossypol cottonseed meal dietary of laying hens.