morphine and Avian-Leukosis

Seventy-two female broiler breeders produced 500 pedigreed chicks that were classified as infected or free of avian leukosis virus (ALV) by assay for ALV in their meconia. The albumen of one egg produced by each dam was assayed for group-specific (gs) antigen by the complement fixation (CF) test and enzyme-linked immunosorbent assay (ELISA). Cloacal swabs of dams were assayed for gs antigen by ELISA. Assays on albumens differentiated between transmitting and nontransmitting dams slightly better than swabs. The ELISA was more sensitive than the CF test on albumens, but more nontransmitting dams were positive by ELISA. The ELISA and virus assay on the same samples of swabs and meconia were highly correlated.

Topics: Animals; Antigens, Viral; Avian Leukosis; Avian Leukosis Virus; Chickens; Cloaca; Complement Fixation Tests; Egg White; Enzyme-Linked Immunosorbent Assay; Female; Immunoenzyme Techniques; Meconium; Poultry Diseases

Progeny chicks from a commercial breeder flock with a high rate of avian leukosis virus (ALV) infection were classified as congenitally or contact infected with ALV on the basis of virus tests on their meconia at hatching and the presence or absence of antibodies at 20 weeks of age. The ALV infection profile, shedding, tumor mortality, and egg production in the congenitally-infected chickens were compared with those in the contact-infected hatchmates. Results show that viremic-tolerant hens classed as congenitally infected consistently shed virus into albumen of their eggs and progeny and 18% died from tumors. In contrast, hens classified as contact infected had a transient viremia; most of them developed antibody to ALV, and only 10% shed virus into albumen and progeny. No mortality from tumors occurred in this group of chickens during the 48-week experimental period, and egg production was significantly higher than in the group classified as congenitally infected. In addition, progeny chickens hatched from the contact-infected group maintained a low rate (2.9 to 3.8%) of ALV infection for the next two generations without further selection. These data further document principles and procedures for reduction of ALV infection in commercial flocks and the considerable economic benefits to be derived therefrom.

Topics: Animals; Antibodies, Viral; Antigens, Viral; Avian Leukosis; Avian Leukosis Virus; Chickens; Cloaca; Female; Meconium; Viremia

A total of 2544 comparisons were used to study the relative efficiency of various test procedures currently used to detect lymphoid leukosis virus infection in chickens. Meconium, blood, cloacal swabs, and egg albumen were collected from day-old chicks and adult hens from four breeder flocks. The phenotypic mixing was used as the biological assay for infectious virus. The complement fixation test and enzyme-linked immunosorbent assays were used as direct assays for the group-specific antigen of the avian leukosis-sarcoma viruses. Analysis of test results of biological assays has shown that blood from virus-infected chicks was more frequently positive than meconium. Also, direct assay for group-specific antigen was as efficient as the biological assays for detection of positive albumen samples from freshly laid eggs. The rate of false-positive reactors recognized by direct assays was lower in albumen samples than in cloacal swabs collected from hens that produce endogenous virus or group-specific antigen. Data also showed a relatively high concordance, ranging from 71 to 100%, between various assays with test materials from adult hens. Progress in reducing rates of exogenous lymphoid leukosis virus infection can be significant if dams are selected on the basis of any one of the test procedures examined. For complete eradication however, day-old chicks should be selected on the basis of the biological assay of blood of individual chicks reared in small groups.

Topics: Animals; Antigens, Viral; Avian Leukosis; Avian Leukosis Virus; Biological Assay; Birds; Complement Fixation Tests; Enzyme-Linked Immunosorbent Assay; Female; Meconium; Microbiological Techniques