Dietary supplementation of 25-hydroxycholecalciferol and its impact on performance, intestinal morphology, and vitamin D status in broilers subjected to coccidiosis vaccine

The objective of this study was to compare the effect of dietary vitamin D3 and 25OH-D-3 metabolite on performance, intestinal integrity, and vitamin-D status of broilers administered a 2X-dose coccidiosis vaccine. Broiler chicks were placed in floor pens for 21-day-trial-period. Experimental dietary treatments were formulated with a mineral-vitamin-premix devoid of D3 and supplemented with dietary 25-OH-D-3 and/or vitamin-D3 from a commercially available source. The dietary treatments consisted of (Control) 2,750 IU/kg vitamin-D supplemented by D3, 2,750 IU/kg vitamin-D supplemented by a 25-OH-D-3, 2,750 IU/kg vitamin-D supplemented 50:50 by D3 and 25-OH-D-3, lastly 1,375 IU/kg vitamin D by 25-OH-D-3. Birds were randomly assigned to vaccinated or not-vaccinated groups resulting in a 4 x 2 factorial arrangement in a completely randomized block design. Twenty-five-male Cobb500 broilers were placed per replicate with 6 pen replicates per treatment. Feed consumption (FC), body weights (BWs), and feed conversion (FCR) were calculated at d 7, 14, and 21. Serum concentration of 25-OH-D-3, tibia breaking strength (TBS), and lesion scores were measured on d 10, and 21. There were significant differences (P < 0.05) in BW, FCR, and TBS between 25-OH-D-3 dietary treatments and Control. Cumulative FCR was improved (P < 0.05) in one or more 25OH-D-3 treatments compared to Control. TBS at d 10 and 21 was greater (P < 0.05) between one or more 25-OH-D-3 treatments compared to Control. Overall, the results indicate dietary 25-OH-D-3 metabolite positively impacts TBS, 25-OH-D-3 in serum, and performance. Dietary supplementation of 25-OH-D-3 can provide an improved safety margin under a coccidiosis vaccine challenge than birds fed D-3 alone.