The effect of dietary supplementation with chromium-enriched soya meal on lymphatic cells in caecal tonsil of laying hens

The study aimed to determine the effects of dietary supplementation with high dose of inorganic chromium from a new additive (soya meal enriched with Cr (III) by biosorption) on lymphatic cells in caecal tonsil of laying hens. The feeding experiment was conducted over 4 weeks on 60 laying hens from Hy-Line Brown line, aged 18 weeks. All birds were kept in a furnished Battery Cage System, in a room with a controlled climate conditions and light regimen of 13-15L:11-9D and were fed either a basal diet - control group (n = 30) or the basal diet supplemented with chromium - Cr-treated group (n = 30). The dietary treatments for Cr-treated group consisted of the basal diet supplemented with 87.7 mg kg−1 chromium from a enriched soya meal (20.588 ± 0.212 mg of Cr(III) g−1). The samples of caecal tonsils were stained against chicken Bu-1, CD4, and CD8α antigens and the positive area fractions were counted. It was revealed that the population of CD4+ cells was significantly higher (p < 0.001) by unchanged number of the Bu-1+ and CD8α+ cells in caecal tonsils of chromium-supplemented hens. The obtained results showed that the supplementation with high dose of chromium from a enriched soya meal stimulates the adaptive immune system in the caecal tonsil what may enhance the response against potentially dangerous antigens.