Relative efficacy of 25-hydroxycholecalciferol supplementation on growth parameters, bone quality, and plasma concentration in broilers

Abstract Among metabolites of vitamin D 3 , 25-hydroxycholecalciferol (25-(OH)D 3 ), also referred to as 25-hydroxyvitamin D 3 , is recognized for its bioavailability and utility in poultry rations. This four-arm randomized controlled trial evaluated the outcomes of three commercial products of 25-(OH)D 3 with varying active concentration on growth performance metrics, bone mineralization, and plasma 25-(OH)D 3 levels in broilers relative to an unsupplemented control. A total of 1,500 Ross broiler chicks were allocated to four treatments with 15 replicate pens of 25 birds in each replicate floor pen. Dietary treatments included: T1 - Basal diet (2000 IU/kg of finished feed) + 0 ppb supplemented 25-(OH)D 3 , T2 – Basal (2000 IU/kg) + Product A (69 ppb supplemented 25-(OH)D 3 ), T3 - Basal (2000 IU/kg) + Product B (69 ppb supplemented 25-(OH)D 3 ), and T4 – Basal (2000 IU/kg) + Product C (34.5 ppb supplemented 25-(OH)D 3 ). Performance parameters were recorded during starter (day 0 to 14), grower (day 14 to 28) and finisher (day 28 to 43) phases. Tibia mineral contents and plasma 25-(OH)D 3 were measured on day 21 and 43. Feed intake did not differ significantly during starter, grower, and finisher phase ( P > 0.05). Body weight gain was higher in Product A birds compared to Product B and Product C from 0 to 43 days ( P < 0.05). There were no differences between groups in tibia bone parameters on day 21. Tibia ash percentage on day 43 was significantly greater in Product A and Product C compared to the unsupplemented control ( P < 0.05). Tibia bone calcium, phosphorus, and density did not differ among treatment groups( P > 0.05). Plasma 25-(OH)D 3 was greater in product A compared to Product B and C at both 21 and 43 days( P < 0.05). All vitamin D 3 supplemented groups had greater plasma 25-(OH)D 3 compared to the unsupplemented control. Mortality rates were unaffected ( P > 0.05) by supplemental Vitamin D 3 . The improved performance of Product A is attributed to its higher active 25-(OH)D 3 concentration and formulation, underscoring that inclusion rate alone does not guarantee biological efficacy. These findings emphasize the importance of evaluating commercial 25-(OH)D 3 products as outcomes may vary depending on the delivery method and the practical context.