Sensitivity of humoral immune parameters of poultry to minor macro- and micronutrient differences in two nutritionally complete layer feeds

The effect of differences in the composition of nutrients of two nutritionally complete layer diets on parameters from innate and adaptive immunity of chickens were examined. The diets were based on ingredients grown either organically or conventionally. As individual differences in nutrient sensitivity have been reported and as the immune system was used as a sensory organ to detect possible effects, layer hens divergently selected for high and low specific antibody (Ab) responses to SRBC, i.e. low line hens and high line hens, reflecting a genetically based differential immune competence were used. The parental line of these hens was randomly bred as the control line, and was used as well. To examine maternal and/or epigenetic effects on nutrient sensitivity, two subsequent generations were studied. In addition, the second generation was challenged with keyhole limpet haemocyanin (KLH). The most pronounced dietary effects were found in the low line birds of the first generation: specific Ab titres to NCD vaccine were significantly elevated in one of the two diets. In the second generation, significant differences were found in Ab and complement responses to the KLH inoculation. Immune competence of the selection lines was not affected. In the second generation control line hens showed the most pronounced effects of dietary treatment in immune responsiveness, with significant effects on specific Ab vaccine titres as well as in innate parameters. The results suggest that small nutritional differences due to the use of different sources of raw ingredients have immunomodulatory effects on innate and adaptive humoral immune parameters. The data indicate the importance of dietary components displaying the capacity to modulate the immune system