IMMUNE RESPONSE INDUCED BY FEED IN GROWING RABBITS

Two litters of eight young rabbits, 21-day old and deprived of feed up till then, were used. Animals were identified and fed ad libitum on diet A or diet B throughout the experiment, until 60-day old; the rabbit does were fed ad libitum on diet N. Diets A and B were formulated in such a way that no raw material was present in both and diet N was a commercial diet. At the beginning and the end of experiment, samples of blood were taken from each young rabbit as well as from their mothers. Dot-immunoblotting technique was carried out to asses the existence of anti-feed antibodies in blood serums, using soluble fractions from the in vitro digestion of diets A, B and N as dietary antigens. Both rabbit does presented high reactivity against all tested diets in both initial and final samples. The serum of rabbits at 21-day old also showed high reactivity against all tested diets. At 60-day old, reactivity of serum of rabbits showed different pattern depending on the diet they consumed. In the most of cases of animals consuming diet A, clear decrease of levels of antibodies against diets B and N but increase or maintenance of levels of antibodies against diet A were observed. In the most of cases of animals consuming diet B, decrease of levels of antibodies against diets A and N was detected together with decrease or maintenance of levels of antibodies against diet B. These results point to the existence of anti-feed IgG antibodies in blood of adult rabbit does, transferred to litter, as well as to a specific immune response of rabbits to the feed that they consumed around weaning of variable intensity depending on the feed composition.