Effect of feeding soybean meal and differently processed peas on the gut mucosal immune system of broilers.
Peas are traditionally used as a protein source for poultry. However, peas contain antinutritional factors (ANF), which are associated with the initiation of local and systemic immune reactions. The current study examined the effect of feeding raw or differently processed peas in comparison with feeding a soybean meal (SBM) based control diet (C) on the gut mucosal immune system of broilers in a 35 day feeding trial. In six replicates, a total of 360 one-day-old male broilers were randomly allocated to four different groups receiving C, or three treatment diets containing raw, fermented, and enzymatically pre-digested peas, each supplying 30% of required crude protein. After slaughtering, jejunal samples were taken for immunohistochemical, flow cytometric, and gene expression analyses. Investigations were focused on the topological distribution of intraepithelial leukocytes (villus tip, villus mid, and crypt region) as well as on the further characterization of the different intraepithelial lymphocytes (IEL) and concomitant pro- and anti-inflammatory cytokines. Broilers receiving the raw or processed pea diets had higher numbers of intraepithelial CD45+ leukocytes in the tip (P = 0.004) and mid region (P < 0.001) of villi than birds fed C. Higher numbers of intraepithelial CD3+ lymphocytes were found in the villus tip (P = 0.002) and mid region (P = 0.003) of birds fed raw or processed pea containing diets in comparison with those fed C. The flow cytometric phenotyping showed a similar relative distribution of IEL among the feeding groups. The expression of intestinal pro- and anti-inflammatory cytokines was affected by feeding the different diets only to a minor extent. To conclude, feeding of diets formulated with raw and processed peas in comparison with feeding a SBM control diet initiated mucosal immune responses in the jejunum of broilers indicated by a quantitative increase of intraepithelial T cells. Further research is needed in order to ascertain the specific factors which are responsible for observed local immune reactions and how these local reactions might affect the immune status and health of broilers.
Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Königin-Luise-Str. 49, 14195 Berlin, Germany.
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Röhe
Institute for Animal Physiology, Department of Veterinary Sciences, University of Munich, Veterinärstr 13, 80539 Munich, Germany.
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Göbel
Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Königin-Luise-Str. 49, 14195 Berlin, Germany.
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Goodarzi Boroojeni
Institute of Animal Nutrition, Department of Veterinary Medicine, Freie Universität Berlin, Königin-Luise-Str. 49, 14195 Berlin, Germany.
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Zentek
D000821:Animal Feed / Q000032:analysis*; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000276:immunology*; D004032:Diet / Q000662:veterinary; D005285:Fermentation; D005511:Food Handling; D018928:Immunity, Mucosal / Q000187:drug effects*; D007583:Jejunum / Q000276:immunology; D007962:Leukocytes / Q000276:immunology; D018532:Pisum sativum / Q000737:chemistry*; D011897:Random Allocation; D013025:Glycine max / Q000737:chemistry*
broiler; feed processing; intraepithelial lymphocytes; mucosal immune system; pea