Study On The Changes Of The Laying Performances And Reproductive Hormone Concentrations With Different Photoperiods In Lvke Chicken

An open egg production period in chicken can be referred to different periods of egg production in one day,which can have direct impact on chicken egg production efficiency and lead to different economic benefits.This research investigates the production efficiency under different photoperiods and corresponding serum gonadal hormone concentrations in order to reveal the distribution of production periods inane open egg production period as well as the change in hormone concentrations.This research divided 240 chickens into A1,A2,A3 and A4 groups averagely.There are two parts:(1)Extreme light test: keeping 16L:8D between 172-196 d in all groups;between 196-198 d,A1-0L:24D,A2-12L:12D,A3-16L:8D,A4-24L:0D,in this experiment we recorded the production efficiency between 172-198 d and the serum hormone concentration at 6:00,9:00,12:00 and 15:00 everyday.(2)Mild light test: this experiment recorded the production efficiency between 199-227 d.All chickens were divided into 4 groups: B1-8L:16D,B2-11L:13D,B3-16L:8D and B4-20L:4D.The results are:1.Egg production and laying rate.24d before extreme light treatment,A1 has the lowest egg production,averagely 680 eggs with only 45.3% egg laying rate.A3 has the highest production of 775 eggs,49.7% egg laying rate averagely.The difference between A1 and A3 is 95 in eggs and 4.4% in rate.Mild light test 29 d,the production and rate has changed with different photoperiod.B1 has 791 eggs with an average of 50 % egg laying rate,B2 has 1052 eggs and 62.4 % in rate,B3 has 924 eggs and 58.6 % in rate and B4 has792 eggs with 50.1 % in rate.2.Production performance and open egg production period.24 d before extreme light treatment: the proportion of continuous egg production in 4 groups between 6:00-10:00 is76.5 %,67.7 % between 13:00-16:00.Mild light test 29 d: the proportion of continuous egg production in 4 groups between 6:00-10:00 is 74.3 %,65.5 % between 13:00-16:00.The continuous egg production starts in the morning and ends at afternoon,7:00-16:00 is the best time period.3.Egg production preference.24d before extreme light treatment: all 4 groups preferred to produce between 9:00-10:00 in the morning.Mild light test 29 d: B1 preferred to produce between 7:00-10:00,B2,B3 preferred to produce between 9:00-12:00 and B4 preferred to produce between 11:00-14:00.4.Serum hormone concentrations.In Trial 1,when treated hens for 72 hours,at 9:00the concentration of FH is significantly higher than those at 6:00,12:00 and 15:00.When treated hens for 48 hours,the FSH concentration is higher than 72 hours.The concentration of LH at 9:00 is higher than those at 6:00,12:00,and 15:00.However,for GnRH,their concentrations show no difference among 6:00,9:00,12:00 and 15:00.In conclusion,with 11:13D photoperiod,the production reaches the highest.The open egg production period is between 7:00-16:00 and the production preference will delay with the increase of photoperiod.Under extreme light condition,the hormone concentration will be maintained properly.This study investigated the preference of photoperiod and corresponding production performance,providing basic information for egg production ability in Lvke chickens.