The Impact Of Energy Intake During Growing Period On Early Laying Performance Of Suqin Green Eggshell Layer Female Parent

The study aims to investigate the impact of energy intake during growing period on the growth,egg laying,egg quality,reproductive organ and gene expression of hypothalamus of strain of local layer,and benefit for local layer growth study and nutrition standard formulation.We select 960 healthy Suqin green eggshell layer female parent with similar weight at the age of 56 days and randomly divided them by single factor into 4 groups,each group included 8 repeats and each repeats included 30 hens.At the age of 9-18 weeks,we fed quantitative diet with crude protein in level of 15.15%,metabolizable energy in level of 10.88?11.30?11.72?12.14MJ/kg to each group of hens,respectively.From the age of 18 weeks,we fed each group of hens on diet in the same nutrition level.Data were collected at the week age of 8-43 weeks,including body weight at the week age of 8 and 12-26 weeks,body measurement traits at the week age of 16 and 43 weeks,reproductive organ at the week age of 16-26 weeks,age at first egg and egg production before the week age of 43 weeks and egg quality at the week age of 21-43 weeks,digital gene expression tag profiling of hypothalamus at the week age of 20 weeks.The result shows:Growth: On body weight,there is very significant difference of energy intake at the week age of 12-20 weeks(P<0.01)and no significant difference of energy intake at the week age of 21-26 weeks.With the increase of age,the difference between each energy group increases.Low to high as per energy level,the shank circumference measurement of four energy group at the week age of 16 weeks are 3.28 cm,3.30 cm,3.34 cm and 3.33 cm,respectively.The first group is extremely significantly less than the third(P<0.01)and significantly less than the fourth(P<0.05);the crown height measurement of four energy group at the week age of 16 weeks are 1.48cm?1.56cm?1.56 cm and 1.60 cm,respectively.The first group is significantly less than the fourth(P<0.05);the shank length measurement of four energy group at the week age of 43 weeks are 8.52cm?8.76cm?8.62 cm and 8.72 cm,respectively.The first group is extremely significantly less than the second(P<0.01)and significantly less than the fourth(P<0.05).Egg laying: Low to high as per energy level,the age at first egg of four energy group are 154.94 d,154.07 d 151.82 d and 147.39 d,respectively.The forth group is extremely significantly earlier than other groups(P<0.01);the egg production of four energy group at the age of 43 weeks are112.09,110.69,112.15 and 116.70,respectively.The forth group is extremely significantly morer than the second(P<0.01)and significantly more than the first and the fhird(P<0.05).Egg quality: Energy intake has some effects on egg weight,egg yolk color and yolk ratio,and has no significant effect on eggshell color,egg shape index and eggshell strength.Reproductive organs: Energy intake has no significant impact on the ovarian basal weight(P>0.05).With the increase of age,ovarian basal weight increases;Mean number of follicles and mean weight of follicles increase with the increase ofage.Gene expression profiling: Energy intake has some effects on hypothalamus gene expression.The differential gene were located on 6 energy metabolism pathways and 11 reproductive pathways by KEGG enrichment anlaysis(P<0.05).