This study was conducted to investigate the effect of dietary betaine on performance, humoral immunity, intestinal immune responses and gut contents osmolarity of broilers in coccidiosis condition. Three supplemental betaine levels (0, 0.6 or 1.2 g kg-1) were fed to 189 mixed-sex broilers chicks which were randomly assigned to 9 floor cages in a completely random design with 3 replicates. To simulate a coccidiosis challenge, at day 28 of age the chickens were inoculated with a mixed culture of Eimeria tenella and Eimeria acervulina via the drinking water. Antibody response to Sheep Red Blood Cell (SRBC) was determined on day 21. The immunoglobulin A (IgA) content was quantified in sera and mucous membrane tissue of intestine. Ileum and cecum contents were measured for osmolarity at 21 and 42 days of age. The supplemented diets with 1.2 g kg-1 betaine improved average daily gain and feed conversion ratio in 21-42 and 7-42 days periods. Antibody response to SRBC was not affected by dietary treatments. Interestingly, sera IgA content was increased in birds subjected to coccidiosis-infection. The IgA content of both sera (p<0.05) and gut tissue (p<0.01) were increased by added betaine to diet. Variations in osmolarity and moisture of both ileum and cecum contents were similar and they were significantly (p<0.001 and p<0.05, respectively) decreased in day 42 measurement by betaine inclusion into the diet. Positive effects of dietary betaine on performance, immunity and digesta moisture and osmolarity redoubles the importance of adding betaine to diet of broilers especially, in stress conditions like coccidiosis-infection.
H. Hamidi, R. Jahanian and J. Pourreza, 2010. Effect of Dietary Betaine on Performance, Immunocompetence and Gut Contents Osmolarity of Broilers Challenged With a Mixed Coccidial Infection. Asian Journal of Animal and Veterinary Advances, 5: 193-201.