Effects Of VA Supplementation On Reproductive Performance,Antioxidant Performance And Tissue VA Deposition Of Geese

Vitamin A(VA)plays an important role in maintaining normal growth and development,reproductive performance,antioxidant function and visual function of animals.At present,the research of VA in breeding fowl diet is mainly concentrated on laying hens and ducks.There are few studies on the appropriate amount of VA in breeding geese diet,which makes the use of VA in breeding geese diet lack of scientific basis in actual production.Our experiment was conducted to study the effects of dietary VA supplementation on reproductive performance,reproductive hormone level,gene expression,antioxidant activity,egg quality and tissue VA deposition of Yangzhou geese breeder geese,and to determine the appropriate amount of VA supplementation,so as to provide reference for the formulation of geese diet.180-day-old Yangzhou geese(75 female geese and 15 male geese)were randomly divided into five treatment groups,15 female geese and three male geese in each treatment group.The control group was fed with the basal diet without VA supplementation,while the experimental group was fed with the basal diet supplemented with 4,000,8,000,12,000 and 16,000 IU/kg of VA.The trial period was 28 weeks.The effects of dietary VA supplementation on reproductive performance,antioxidant activity,egg quality and VA deposition in tissues of Yangzhou geese breeder were studied.(1)Effects of dietary vitamin A on reproductive performance,serum reproductive hormones and gene expression related to reproductive axis in geeseDietary supplementation of 12,000 IU/kg of VA could significantly increase the daily laying rate,fertilization rate,hatching rate of fertilized eggs,hatching rate of hatched eggs and healthy chicks(P<0.05).Through linear regression analysis,it is concluded thatsupplementation of 14,000 IU/kg of VA could significantly increase the serum progesterone(P)and estradiol(E2)contents of geese at the beginning of parturition(P<0.05),the serum P,E2 and testosterone(T)levels of geese during peak laying period were significantly increased by adding 10,000 IU/kg VA(P<0.05),VA supplementation of 12,000 IU/kg significantly increased the relative expression of gonadotropin releasing hormone(GnRH),follicle stimulating hormone alpha(FSH alpha),luteinizing hormone(LH)and follicle stimulating hormone receptor(FSHR)genes in reproductive axis of geese(P<0.05).(2)Effects of Vitamin A Supplementation on Antioxidant Activity and Vitamin A Content in Liver of GeeseDietary supplementation of 10,000 IU/kg VA significantly increased the liver GSH content,GSH-PX activity,SOD activity,T-AOC,catalase(CAT)activity of geese(P<0.05),significant reduction of malondialdehyde(MDA)content(P<0.05).With the increase of dietary VA level,the content of VA in liver increased significantly(P<0.05).(3)Effects of dietary vitamin A supplementation on egg quality,antioxidant activity and vitamin A content in geeseDietary supplementation of 10,000 IU/kg VA could significantly increase egg specific gravity,shell thickness,yolk color,Hashimoto unit and yolk ratio(P<0.05).supplementation of 10,000 IU/kg VA could significantly increase SOD activity,MDA content,T-AOC and GSH content(P<0.05),supplementation of 12,000 IU/kg VA could significantly increase VA content in geese eggs(P<0.05).In summary,Vitamin A content in basic diet is 1 200 IU/kg,adding appropriate amount of VA in diet can improve reproductive performance,antioxidant activity,egg quality and VA content in tissues of breeding geese.It is suggested that adding 12,000 IU/kg of VA in Yangzhou geese diet during breeding period can increase VA level in female geese diet properly in the early stage of production and reduce the amount of VA in the end of laying period.