The Effect On Chicken's Product Performance And Immune Effect Of Vaccine

Avian leukosis is a viral disease of great harm that occurs frequntly in aquaculture, and it is a kind of various contagious benign and malignant tumors caused by/ grows out of Leukemia/sarcoma of retroviruses families in birds. By means of detecting the p27 antigen of Avian leukosis in a Chicken Farm in tongchuan of shaanxi province, and comparing the production target of immunized chickens and the normal chickens, to research the effect of Avian leukosis on laying rate, the average weight and the failure rate of eggs, the rate of death, as well as the immunosuppressive effects caused by vaccines, so as to provide references for controlling the avian leukosis.Detect ALVp27 antigen of 4 kinds and 3 generations of chickens by ELISA, except the grandparent chickens, others all showed different degrees of positive rate. The positive rate of Parental chickens, Hy-line Brown of LAYING HENS, and LOHMANN were 4 2.80%, 53.6%, and 0.5% respectively.Sampling randomly from two henhouses of the layer farm,we recorded three average varieties: the laying rate, the weight and the failure rate of eggs per week . Compared with the chronic myeloid leukemia (CML) negative chickens, the age at first egg and total laying rate of the positive chickens were respectively earlier and lower than negative chickens by 3d and 4.22%. The difference between positive and negative chickens was not significant (P>0.05) in the first phase, nevertheless, in the second and the third phases, the laying rate of negative chickens was significantly higher than the positive chickens(P<0.01). Meanwhile, the increase speed of average weight of negative was higher than positive chickens, although the difference was not striking in the first phase (P>0.05), the average weight of negative chickens in the second and the third phases were respectively significantly stronger(P<0.01) and significant(P<0.05) than positive chickens. Moreover, the failure rate of eggs of negative chickens in the first and the second phases were both significantly lower than the positive chicken(sP<0.01), and there was no obvious difference in the third phase((P>0.05). The differences of the average laying rate and average weight between positive and negative chickens mostly come from the second and the third phases, and they were not significant in the first phase. The result showed that the effect of positive chickens on the growth performance in the earlier stage was limited, however, as the days of age increasing, the avian leukosis will exert a growing influence on the growth performance. By using the method of random sampling, recorded the rate of death per week, the overall death number of positive chickens was strikingly higher than negative. In addition, before 12 weeks, the rate of death of positive chickens was lower than negative; however, 12 weeks later, the rate of death of positive chickens was obviously higher than negative.Collected serum samples of positive and negative chickens randomly, measured antibody of ND,H9,H5(Re-4),H5(Re-5)by HI, the negative chickens had higher average titer, and H9 got the highest titer. Moreover, the antibody dispersion of negative chickens was overall small. In addition, the average antibody of positive chickens were lower; moreover, the antibody dispersion of positive chickens was larger.