EFFECT OF HEMOGLOBIN STATUS ON HUMORAL IMMUNE-RESPONSE OF WEANLING PIGS DIFFERING IN COPING STYLES

The effects of hemoglobin (Hb) status and coping style of pigs on perf ormance and humoral immune response were studied. Twenty-four, 4-wk-ol d crossbred barrows were assigned to groups of three pigs based on wei ght and litter origin. Groups were allotted according to a 2 x 2 facto rial treatment arrangement: two blood Hb concentration classes (low vs high) and two immunization procedures (control vs immunized). Immuniz ed pigs received an antigen cocktail containing keyhole limpet hemocya nin (KLH), ovalbumin (OA), and tetanus toxoid (TT) at. weaning. Additi onally, pigs were stratified according to behavioral coping style in r esponse to exposure to a stressor. During 41 d after weaning (approxim ate time of immunization), blood Hb concentration, ADG, and ADFI were measured weekly and serum antibody titers to KLH, OA, and TT twice wee kly. Average Kb concentration differed between low and high I-Ib pigs (P < .001; 10.0 vs 12.0 g/dL), but this difference declined with time after weaning. Neither immunization procedure nor coping style affecte d Hb concentrations, In addition, ADG and ADFI were unaffected by any of the treatments. However, ADG was slightly greater in high Hb status pigs (586 vs 633 g/d) and was paralleled by a slightly greater ADFI i n high Hb status pigs (812 vs 899 g/d). Antibody responses were negati vely or not related to Hb status at weaning. Antibody responses (depen ding on isotype and antigen) were or tended to be lower in pigs with h igh blood Wb concentrations. Behavioral coping style strongly affected humoral immune responsiveness; enhanced or-accelerated antibody respo nses were found in pigs that had a passive coping style.