Effect of dietary histamine on broiler chickens infected with avian reovirus S1133

One-day-old broiler chickens were infected with either of two vaccine strains of avian reovirus S1133 and fed diets containing 0.2% histamine dihydrochloride for 21 or 35 days. Control groups received either or neither of these treatments. The most notable virus-histamine interaction observed was increased (P less than 0.01) early mortality of chickens infected with the more virulent (pullet) vaccine virus. Histamine in the diet did not affect seroconversion rates or the incidence of stunting in virus-infected chickens. Other evidence of virus-histamine interaction was proventricular enlargement and decreased (P less than 0.05) weight gains in chickens infected with the less virulent (chick) vaccine virus, but these signs were observed inconsistently. The possible clinical significance of these observations is discussed.