Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/28/2002
Publication Date: 8/1/2002
Citation: Yonash, N., Bacon, L.D., Smith, E. 2002. Concentration of immunoglobulin g in plasma varies among 6c.7 recombinant congenic strains in chickens. Poultry Science. 81:1104-1108. Interpretive Summary: The ability of chickens to respond to disease organisms is dependent on blood cells and on unique proteins called immunoglobulins that are present in blood. Immunoglobulins are the product of one type of cells in the blood and immune tissues of the body, and are selected in a way that results in many forms called antibodies that have different specificity to fight all disease organisms. Two unrelated lines of chickens that are known to differ in disease resistance are shown to possess different quantities of immunoglobulins in their blood. The two strains of chickens have been mated in a way to develop 19 strains that are genetically 88% identical, but 12% of the hereditary units are unique in each strain. For several generations two of the derived strains were different from five other strains regarding immunoglobulin concentration in the blood. These strains may be useful for researchers in identifying the hereditary units that control immunoglobulin concentration, and for understanding the relationship between these hereditary units and resistance to various diseases of chickens.
Technical Abstract: Chicken lines 6 and 7 were inbred during selection for resistance or susceptibility to viral induced tumors. A sandwich ELISA assay was adapted to define the milligrams per milliliter of gamma Ig (IgG) in plasma from chickens of lines 6 and 7, as well as 19 recombinant congenic strains (RCS). Each RCS resulted from a 7 X 6 F1 and two backcross matings using 6 as the recurrent female line. The IgG levels in the RCS were evaluated after 4-7 generations of sib-matings, when each RCS was becoming inbred and fixed for a different 12.5% of the 7 genome. In three generations approximately 24-wk-old chickens of line 7 had higher levels of plasma IgG than chickens of line 6 (P<0.05). None of the RCS had repeatable IgG levels comparable to line 7. However, in the last two generations, two of the 18 RCS strains had higher IgG levels than nine with low IgG levels (P<0.05). There was no correlation between a RCS's IgG level and resistance to Marek's disease. We conclude selected RCS may be useful for identifying genes that determine differences in IgG levels, as well as for understanding the relationship between genes determining IgG levels and other traits that differ between lines 6 and 7.