| In addition to certain casualties, it also caused effects on post-laying performance after the chickens infected with Infectious Bronchitis Virus (IBV). It can cause inestimable economic losses to poultry industry. Our group has research on IBV impact on the morphology of oviduct, but roles of IBV on post-laying performance was rarely reported up to now. In order to investigate the pathogenic mechanism of oviduct eccyliosis, 10-day-old chicklings were infected artificially with M41, hormone and hormone receptor levels were measured at perinatal chickens. The paper was divided into three parts:1. IBV-M41 resuscitationAbout serial in vivo passage and the anabiosis of IBV-M41 virus, IBV-M41 inoculated into non-Immune hatching eggs and we were observed with the death status of Chicken Embryo. By Reed-Muench menans EID50 is 10-6.2/0.2 mL, By Serological testing allantoic fluid of HA and HI were determined. The results showed that: IBV-M41 can be used for subsequent experiments.2.Influence of IBV-M41 on the expression of estrogen receptor,progesterone receptor and IGF-I in oviduct of Layer Chickens.RT-PCR was used to detect the ER/PR mRNA and IGF-I expression of the oviduct (the magnum, isthmus, fimbria and shell gland). The results as follows: there were expression of ER /PR mRNA and IGF-I in oviduct; the expression of ER and PR in vaccinated of IBV-M41 was significantly decreaced (P<0.05), but the expression of IGF-I was significantly increased (P<0.05). The study reveals that IBV can affect the development of oviduct by reducing the expression of ER and PR, and so downgrade responsing capabilities of the estrogen; IGF-I could act on the oviduct through autocrine or paracrine way, to promote the growth of chick oviduct..3. Influence of IBV on the endocrine pattern and egg production performance of chickenThe activity of laying rate, egg weight and the concentration of GH, thyroid hormone and estrogen in plasma of laying chicken were quantified to analyze the effect of M41 IBV infection on egg-laying and oviduct development. The results showed that: Although there were no significant decreases in egg weight under IBV infection (P<0.05), it could induced apparent delay of egg laying (P<0.05). There were no significant decreases in concentration of GH under IBV conditions (P>0.05), but making the change concentration of GH presented a delay trend compared with control group; IBV decreases secretion of E2. It reaches apparent expression between 80 d and 100 d (P<0.05) Compared to the normal group; level of T3 concentration infected with M41 has a tendency of decline between 60 d and 80 d (P>0.05). When it reaches 100 d, the difference arrives at apparent expression. , there is no difference there after; In contrast to the changes of T3 secretion, IBV infection tend to increases expression of T4, it seemed. that the transformation of T4 to T3 in vivo may be declined in the infected group .The paper also described the change rules of concentration of GH, E2, T3 and T4 in plasma around the onset of laying.From above results we can conclude that: IBV can interfere with hormone and hormone receptor levels expression of oviduct, so retard the normal development of oviduct.
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