Effects Of Different Photo Period On Laying Performance,Immunity And Intestinal Microbes In Duck

Illumination is an important factor that affects the reproductive performance of laying ducks.In this parper,we used Shanma Duck as research object,and the effects of different light durations on laying performance,follicular development,immunity,and intestinal microflora in laying ducks were studied by giving different durations.The aim of this study is to reveal the regulatory mechanisms and important factors involved in the process of follicular development and egg production inducks,and also provide scientific basis and objective data for guiding duck production.Three groups of 52-week-old Shanma ducks were pre-fed with light for 18 h(18L:6D).After 7 d,light was maintained for 18 h in D group(18L:6D),S(8 L:16D)and L group(24L:0D)received 8 h light and 24 h light,respectively.The test duration is 47 d.The results showed that the melatonin level was decreased by prolonging(P >0.05)or shortening(P < 0.01)the illumination time.Prolonging the illumination time can promote egg production in the ducks within a certain period of time,shortening the illumination time inhibited egg production in laying ducks.With the continuation of egg laying time,GnRH and FSH levels increased blood(P < 0.01).Prolonging the illumination time decreased GnIH levels(P < 0.01),and increased FSH and E2 levels(P < 0.01 and P < 0.05).Shortening the illumination time increase the hormone levels of FSH(P < 0.05),GnIH and GnRH in blood.In addition,the level of PRL increased in all groups(P < 0.01),which increased most in S group.Prolonging or shortening the illumination time decreased the GnRH mRNA levels(P > 0.05)and increased the GnIH mRNA levels(P < 0.01).NPFFR2,mel-1b,and GPR50 m RNA were expressed in the hypothalamus and pituitary,whereas mel-1a mRNA was only expressed in the hypothalamus.Shortening the illumination time can increase the liver(P > 0.05)and spleen index(P < 0.01),and increased the content of cholesterol and triglyceride(P < 0.05)in duck.Prolonging or shortening the illumination time increased the globulin/albumin ratio(P < 0.05),and the levels of T3 and T4.The SOD and LDH also increased and maintained at a reasonable level,so that increased the body immunity of ducks.Duck intestinal microbiota is mainly consists of four dominant phylums,including thick-walled,clostridial,pseudomorphic,and deformed.Different illumination time has no decisive influence on the basic structure of the intestinal microflora,but affects the proportion of each phylum and genus,and affect the ultimately fauna microflora of ducks.