Persistence of passive immunity against some important viral diseases and feed conversion in chickens fed diet supplemented with probiotic

Abstract

The ban of antibiotic growth promoters due to increased bacterial resistance and drug residues in poultry production, together with consumer's demand for “natural” products, have encouraged increase in the use of alternative growth promoters like probiotics. This study evaluated the effects of probiotic supplemented diet on the feed conversion ratio (FCR) and passive immunity against Newcastle disease (ND) and Infectious Bursal Disease (IBD) in chickens. Forty, one day-old broiler chicks were randomly selected into two groups: No probiotic and probiotic fed groups. The weight gained and FCR were monitored while blood samples for serum were collected from five birds per group weekly, for four weeks. Haemagglutination inhibition (HI) and passive HI tests were conducted to evaluate the levels of passive immunity (maternally derived antibody) in the different groups. There was a significant improvement in weight gain and FCR of birds fed the probiotics. Maternally derived antibody (MDA) against ND and IBD in the chicks were high at week 1. There was a delay in the decay of MDA against ND and IBD in the probiotic fed groups although MDA levels against both diseases were almost the same at week 3 in both probiotic fed and no probiotic groups. It could be concluded that probiotics can facilitate increased body weight, FCR and persistent passive immunity in chickens.