Effect of 25-hydroxycholecalciferol Supplementation on Broiler, Layer and Turkey Birds Growth Performance and Immune System.

摘要

In vitro and in vivo studies were conducted to identify the effects of 25-hydroxycholecalciferol (25(OH)D) supplementation on poultry immune cells function, cytokine production, and production parameters following an inflammatory or coccidial challenge. Supplementing chicken macrophages with 25(OH)D in the presence of LPS increased nitrite production, mRNA amounts of IL-1beta, IL-10, 1alpha-hydroxylase and 24-hydroxylase in HD11 cells. Treating HD11 cells with 25(OH)D decreased IL-10 mRNA by 1.7-fold, but 1,25(OH)2D treatment increased the amount of IL-10 mRNA (P > 0.01) post-coccidial antigen treatment. T cell line, ConA-B1-VICK, stimulated with 100 nM 1,25(OH)2D or with supernatants from HD11 cells treated with 25(OH)D plus LPS had 1.3-fold less (P > 0.01 ) IFN-gamma mRNA compared to the group treated with 25(OH)D.;Broiler birds were fed a basal diet supplemented with either cholecalciferol (3000 IU/kg) or 25(OH)D (69 mug/kg). At 21 and 35 d of age birds supplemented with 25(OH)D gained approximately 2.5 % (P = 0.03) and 3.8% (P > 0.01) respectively, more body weight than the birds supplemented with cholecalciferol over the 24 h post-LPS injection and decreased IL-1beta mRNA in the liver compared with those birds fed cholecalciferol (P > 0.01). Layer birds were fed a basal diet supplemented with 25(OH)D at 6.25, 25, 50 or 100 mug/kg and at 21 d of age orally challenged with live coccidia oocysts. Compared to the control birds fed similar levels of 25(OH)D and unchallenged with the coccidia oocyst, birds challenged with the coccidia oocyst had 15 % reduced BW gain in the groups supplemented with either 6.25, 25, and 50 mug/kg of 25(OH)D but had only 4 % reduced BW gain in birds fed 100 mug/kg of 25(OH)D (P > 0.01). At 15 d post coccidia challenge, birds fed 100 mug/kg 25(OH)D and challenged with coccidial oocysts had 17% more CD4+CD25+ cells (P = 0.02) in the cecal tonsil compared to the birds fed 100 mug/kg 25(OH)D and unchallenged with coccidial oocysts. At d 6 post coccidia challenge, among birds challenged with coccidial oocysts, birds fed 100 mug/kg 25(OH)D had 3.4-fold (P = 0.14) decrease in IL-1beta and 4.9-fold increase in IL-10 mRNA amounts in the cecal tonsils compared to birds fed 6.25 mug/kg 25(OH)D.;Turkey poults were fed a basal diet supplemented with 25(OH)D at 27.5, 55, 82.5 or 110 mug/kg and at 21 d of age orally challenged with live coccidia oocysts. At 21 d of age, there was a trend in increasing the mean BW of birds supplemented with 25(OH)D at 82.5 mug/kg (P = 0.09).;In conclusion, higher doses of 25(OH)D supplementation improved BW gain in broiler birds post-LPS challenge and decreased the inflammatory cytokine IL-1beta. In layer birds post-coccidial oocyst challenge, birds supplemented with the highest dose of 25(OH)D had the least decrease in BW gain along with an increase in the percentage of T-regulatory cells and anti-inflammatory cytokine IL-10. In turkey poults supplementing with high doses of 25(OH)D supplementation increased mean BW and post-coccidial oocyst challenge there was still an increased BW gain.