Effects Of Off-season Breeding On Egg-laying Performance,Serum Biochemical Indexes And Related Reproductive Hormones Of Zhedong White Geese

Off-season breeding technology is a measure to promote the production of animals in the non-oestrus season through human intervention.It has been widely used in a variety of poultry production,and has achieved good social and economic benefits.Zhedong white goose has typical seasonal breeding characteristics and the egg producing period is concentrated from December to February of the following year.Winter breeding not only increases the cost of feeding and the loss of goose seedlings,but also the lower economic due to imbalance relationship between market supply and demand.Moreover,the seasonal reproductive characteristics cannot produce substantial and stable economic income.Therefore,this study focused on Zhedong white goose,which were reared in normal season and implemented off-season rearing technology respectively in Xiangshan,Zhejiang Province.We counted the egg production performance during the test period and collected the blood and tissue samples to performed polymerase chain reaction technology to survey the effect of offseason breeding on egg laying performance,serum biochemical indicators and related hormone secretion of Zhedong white geese.And provide a theoretical basis for the popularization and application of Zhedong white geese off-season breeding technology.1.Effects of off-season breeding on egg production performance of Zhedong White GooseIn order to explore the influence of off-season breeding technology on the egg production performance of Zhedong white goose,we selected 1000 normal seasonal breeding Zhedong white geese as the control group,and 1000 anti-seasonal breeding Zhedong white geese as the experimental group.The two groups were provided with independent production areas and feeding equipments.The egg production,egg fertilization rate,and hatched chicks of the two groups in each month of the production cycle were counted.The results show that:①The peak period of laying more than 4000 eggs per month in the anti-seasonal breeding group can reach 3 months,which is increased by 15.62%respectively compared with the peak period of laying in the control group,indicating that the antiseasonal breeding technology can prolong the duration of the peak period of laying in Zhedong white geese and maintain a high level of laying rate in the peak period of laying.②The number of eggs in the anti-seasonal breeding group decreased rapidly after the peak of egg laying,and entered the off-season one month earlier than that in the control group.In the anti-seasonal breeding group,the egg fertilization rate in November increased by 4.13%compared with the control group,and the hatching rate of hatching eggs and fertilized eggs at the peak of egg laying increased by 2.77%and 2.3%compared with the control group respectively.2.Effects of off-season breeding on the changes of serum biochemical indexes of Zhedong white goose.We collected goose blood from July to September during the peak egg production period of the off-season breeding group.Serum was separated from blood and relevant biochemical indicators were detected.The results showed that compared with the control group,the serum P,ALB,TG and TC contents of the off-season breeding group were significantly increased at different time points（p<0.05）,this may be related to the impact of minerals,proteins and fat during the peak egg production period.It is related to the increased demand for nutrients such as fat;serum AST activity,CREA and BUN contents were increased at different time points（p<0.05 or p<0.01）,but they were all within the normal reference value range.This indicated a strong metabolism at the peak egg production period.There were no significant differences in other indicators with the control group（p>0.05）.3.Effects of off-season breeding on serum reproductive hormone levels and expression of related regulatory genes in Zhedong White gooseThe off-season breeding group started from April,and the normal breeding group started from August.We collected blood once a month to separate serum and the content of related reproductive hormones was deteccted.In addition,the Zhedong white goose in the off-season breeding group and the control group during the breeding period were selected,and the hypothalamus,pituitary and ovarian tissues were collected,and the relative expression of reproductive-related hormone genes in the tissues were detected by qRT-PCR.The results showed that,the serum LH,FSH,P4,and E2 contents in the off-season breeding group were higher than the control group（p<0.05 or p<0.01）at the peak egg production period.Compared with control group,the levels of serum T3 and T4 were significantly increased（p<0.05）,but there was no difference in serum PRL concentration（p>0.05）.It showed that off-season breeding increased the reproductive hormone level of Zhedong White Goose,and the increase of thyroxine during the off-birth period was beneficial to growth,development and material metabolism.qRT-PCR was used to detect the relative expression of reproductive-related hormone genes in tissues.The results showed that,compared with the off-season breeding group,the expression of GnRH in the hypothalamus of the control group was extremely significantly increased（p<0.01）,and the expression of GnRH,FSH and LH genes in the pituitary Significantly or extremely significantly increased（p<0.05 orp<0.01）,ovarian GnRH gene expression was extremely significantly increased（p<0.01）,while pituitary VIP and PRL gene expression was significantly or extremely significantly decreased（p<0.05 or p<0.01）.The results indicated that the gene expression levels of reproductive hormones related to hypothalamus,pituitary and ovary were consistent with the off-season reproduction group in the offbirth period and the control group in the high-yield period.Conclusion:The out-of-season breeding of Zhedong white geese can prolong the duration of peak laying period and egg production during peak laying period,which can bring better economic benefits for farmers.Anti-season breeding technology application won’t affect Zhedong white geese physiological function index,anti-season breeding groups of the reproductive cycle of serum hormone level change trend is consistent with the control group,and by organizing related hormone gene expression quantity test verified,anti-season breeding technology application won’t affect the Zhedong white geese reproductive hormone secretion disorder.