Humoral immunity in chicks experiencing marginal vitamin B-6 deficiency.

An economical vitamin B-6-deficient ration that was palatable to broiler chickens was prepared and fed to 1-day-old chicks. The experimental ration was a typical soy-glucose ration. Vitamin B-6 was removed by washing the soybean meal with water. Microbiological analysis revealed that the washed ration contained 0.45 mg vitamin B-6 per kilogram. Experimental rations were formulated to contain 0.5, 1.0 and 3.0 mg supplemental pyridoxine x HCl per kilogram of ration. These supplemental levels produced the following total pyridoxine concentrations in the diet: 0.95, 1.48 and 3.18 mg pyridoxine x HCl activity per kilogram of diet. Chicks were grown to 7 weeks of age and characteristic vitamin B-6 deficiency signs were quantitated and/or observed. Notable signs in chicks receiving 0.5 mg added vitamin B-6 were increased mortality, decreased body weight gain and increased incidence of abnormal leg conformation. The humoral immune system of broiler chicks that were moderately deficient in vitamin B-6 was investigated. Marginal pyridoxine deficiency caused significant reduction in antibody levels to sheep red blood cells (SRBC) and relative levels of IgM and IgG during the peak and degradation phases of the primary response. During the hyperimmune response total anti-SRBC levels were not affected; however, relative levels of IgM and IgG were lowered.