Classic and Non-Classic Effects of the Duration of Supplementation of 25-Hydroxicholecalciferol in Broiler Chicken Diets

Simple Summary Genetic programs of modern commercial-type broiler chickens are based on growth performance parameters associated with muscular growth, feed efficiency, and meat and breast yield. Therefore, highly bioavailable vitamin D-3 to sustain optimal muscle and bone development is necessary. In the present study the effect of different durations of supplementing of 25-hydroxycholecalciferol (25(OH)D-3) in broiler chickens was evaluated. Growth performance response, carcass and cuts yield, bone resistance, plasma concentration of 25(OH)D-3, and expression of the mTOR gene were evaluated. The use of 25(OH)D-3 in the diets for broilers during different feeding periods did not influence growth performance but increased the plasma concentration of 25(OH)D-3, and increased breast yield as the duration of the supplementation was extended. The supplementation of 25(OH)D-3 increased breast yield and protein deposition in the breast muscle which may have been a result of the epigenetic changes caused by this vitamin D (Vit D) metabolite. The present study aimed to determine the effect of different times of supplementation of 25-hydroxycholecalciferol (25(OH)D-3) in broiler chickens on the performance, carcass and cuts yield, bone resistance, plasma concentration of 25(OH)D-3, and expression of the mTOR gene. The treatments were a control diet (CD) supplemented with 3000 IU vitamin D-3/kg of feed from 1 to 46 d, or the CD + 2760 IU (69 mcg) of 25(OH)D-3/kg of feed from 1 to 21 d, from 1 to 35 d, or from 1 to 46 d. The period of supplementation of 25(OH)D-3 did not affect the growth performance of broilers, but the breast meat yield was linearly increased in response to increasing days of supplementation (p < 0.05). Birds supplemented with 25(OH)D-3 at the time of the analysis showed an increase (p < 0.05) in the plasma concentration of 25(OH)D-3 when compared to non-supplemented birds. The mTOR gene expression (p < 0.05), and breast protein deposition (p < 0.05) presented a quadratic response related to the supplementation period of 25(OH)D-3. The fat content of the breast linearly decreased (p < 0.05) as the period of supplementation was extended. The results also showed a positive linear correlation between mTOR expression and 25(OH)D-3 plasma levels (r = 0.593; p < 0.05).