As research in the area of nutritional modulation of immune function has increased, it is becoming apparent that nutrient needs for immunity do not coincide with those for growth or skeletal tissue accretion. In this view an experiment was designed that 1134 broilers received supplemental Zn-Met and betaine with or without feed restriction to check their effects on humoral immunity and increasing resistance in Eimeria infection. Chickens consumed food ad libitum or was restricted on alternate days from 11 to 18d of age. Supplemental Zn-Met were 0, 40 or 60 ppm and basal diet contained 74 ppm zinc. 0, 0.6 and 1.2 kg/ton betaine were added to diets. Antibody response to SRBC were determined on d 21. At 28 d of age, the chicks were inoculated, via the drinking water, with a mixed culture of two Eimeria species to simulate a coccidiosis challenge. Ilieum and cecum content were measured for osmolarity at 21 and 42 d of age. Zn-Met could not elevate any performance factors but betaine and feed restriction decreased feed convertion ratio. Supplemented diets with 1.2 kg/ton betaine improved average daily gain at 21 to 42 d period. Antibody response to SRBC increased by 40 ppm of Zn-met (p 0.05) and feed restriction (p 0.01). Variations in osmolarity of ileum and cecum content were similar and they decreased by 1.2 betaine level and feed restriction significantly. Sera IgA levels increased with coccidio-infection and its amount either in sera and gut tissue increased by increasing level of Zn-Met and betaine in diet (p 0.01). Farther more feed restriction increased IgA level significantly.
