Effect of colostrum curd on humoral and cellular immune response of broiler chickens at vaccination against salmonellosis

Abstract

Salmonellosis continues to be a topical issue in poultry farming and veterinary medicine. Despite widespread vaccination, its effectiveness is limited by variability depending on the type of vaccine, serological specificity and administration technique. In this regard, the search for immunomodulatory drugs capable of increasing the effectiveness of specific prevention continues, and one of the promising areas is the use of colostrum and its processed products. The research goal was to evaluate the effect of colostrum curd on the humoral and cellular immune response of broiler chickens at vaccination against salmonellosis. During the experiment, it was found that the inclusion of colostrum curd in the diet of poultry of the trial group led to a significant increase of the level of γ-globulins (+21.54% by day 30), phagocytic activity (+12.78%) and phagocytic index (+16.20%) of neutrophils compared to the control group. The difference of serum lysozyme activity compared to the control values was 10.57%, and that of bactericidal activity - 15.39%. The introduction of colostrum curd into the diet as an immunomodulator against the background of salmonellosis vaccination also stimulated an increase of the level of circulating immunoglobulins (by 11.33%) and total protein (by 8.13%) by the 30th day of the experiment. Of the greatest importance was a significant increase in the titer of specific antibodies to the causative agent of salmonellosis in the trial group at all stages of the study (+32.94% on day 7, +37.50% on day 14 and +56.76% on day 30) indicating a significant increase in the post-vaccination immune response. The data obtained indicate the effectiveness of using colostrum curd to increase the immune status of vaccinated poultry.