ANTIBODY-RESPONSES AND BODY WEIGHTS OF CHICKEN LINES SELECTED FOR HIGH AND LOW HUMORAL RESPONSIVENESS TO SHEEP RED-BLOOD-CELLS - 1 - EFFECTOF ESCHERICHIA-COLI LIPOPOLYSACCHARIDE

Antibody (Ab) responses to i.m. administered SRBC and BSA, and i.p. ad ministered Escherichia coli lipopolysaccharide (LPS), and BW at variou s times after treatment, were measured in chicken lines divergently se lected for high (H) and low (L) Ab responses to SRBC, and in a randomb red control line (C). The Ab responses to SRBC and BSA, but not LPS, w ere significantly affected by line by treatment interactions. Levels o f antibodies to SRBC and BSA were higher in the H line than in either the C or L line (P < 0.05). Administration of LPS did not affect Ab re sponses to SRBC, but Ab responses to BSA were decreased in birds that received BSA and LPS simultaneously. Body weights of C and L lines wer e significantly higher than BW of H line birds at all times. Lipopolys accharide injection induced an acute, but transient reduction of BW ga in, which was not affected by line. Antibody responses to SRBC and BSA were negatively correlated with BW. During the experimental period, h owever, percentage BW gain and humoral responsiveness were positively correlated. A higher percentage BW gain growth was seen in H line bird s at the end of the experimental period. The present results confirm t he hypothesized acute cachectin nature of LPS, but the relationship be tween live BW (gain) and immune responsiveness in chickens remains to be further clarified.