Effects of dietary 25-hydroxyvitamin D3 (25(OH)D3) supplementation on production performance, egg quality, tibia quality and mineral metabolism of ducks during peak laying period in the cage rearing system.

内容摘要

25-Hydroxyvitamin D3 (25(OH)D3) has been reported to improve production performance and egg quality in ducks during late laying period, but its effects during the peak laying period remain rarely studied. The aim of this study was to investigate the effects of dietary 25(OH)D3 supplementation on the production performance, egg quality, tibia quality and mineral metabolism of ducks during peak laying period in a cage rearing system. A total of 360 Liancheng white laying ducks at 30 weeks (wks) of age were randomly assigned to 5 groups, each consisting of 6 replicates with 12 ducks per replicate. Ducks were fed a basal diet with 25(OH)D3 supplementation at 0, 1000, 2000, 3000, and 4000&#x2009;IU/kg throughout the trial for 8 wks. One-way ANOVA was employed to assess the influence of supplementation level, and linear and quadratic regression analyses were performed for statistical evaluation of dose-dependent effects. 25(OH)D3 supplementation linearly and quadratically increased the laying rate, average egg weight and egg mass and quadratically decreased the feed conversion ratio (FCR). The mean of eggshell strength and thickness at 4 and 8 wks increased linearly and quadratically with increasing 25(OH)D3 levels, and the 4000&#x2009;IU/kg 25(OH)D3 increasing the eggshell thickness by 5.7% (at 4 wks) and 2.9% (mean of those at 4 and 8 wks) relative to those of the non-supplemented group. At the end of wks 4 and 8 of the trial, serum 25(OH)D3, bone glutamyl protein (BGP) and carbonic anhydrase (CA) increased linearly (P < 0.05), and serum parathyroid hormone (PTH) decreased linearly (P < 0.05); the 4000&#x2009;IU/kg group had the highest serum 25(OH)D3 (4.24&#x2009;ng/mL) and BGP (3.11&#x2009;ng/mL) concentrations at 8 wks. Additionally, the tibial breaking strength, trabecular bone number, BGP content, and alkaline phosphatase (ALP) activity and mRNA levels increased linearly with 25(OH)D3 supplementation (P < 0.05). The optimal dietary 25(OH)D3 supplementation levels were approximately 2355, 2347 and 3269&#x2009;IU/kg on the basis of the quadratic model of the laying rate, FCR and eggshell strength, respectively. In summary, 25(OH)D3 supplementation improved the production performance and eggshell quality of ducks during peak laying period by maintaining calcium and phosphorus homeostasis and enhancing tibia quality. A diet that contains 2347-3269&#x2009;IU/kg of 25(OH)D3 displayed beneficial effects on maintaining calcium and phosphorus homeostasis, and improving the tibial quality, which was recommended for ducks during peak laying period in the cage rearing system (30-38 wks of age). 25-Hydroxyvitamin D3 (25(OH)D3) has been demonstrated to improve production performance and egg quality in ducks during late laying period. However, its effects on ducks during peak laying period in the cage rearing system within a cage rearing system remain inadequately explored. The purpose of the present study was to investigate the effects of dietary supplemental levels of 25(OH)D3 on the production performance, egg quality, tibia quality and mineral metabolism of ducks during 30-38 wks of age in a cage rearing system. Ducks were fed a basal diet without 25(OH)D3 supplementation or with 25(OH)D3 supplementation at 1000, 2000, 3000, and 4000&#x2009;IU/kg throughout the trial for 8 wks. The results indicated that dietary 25(OH)D3 supplementation improved the production performance, eggshell and tibia quality and mineral metabolism of ducks during peak laying period. Supplementing the basal diet with 2347-3269&#x2009;IU/kg 25(OH)D3 is recommended for laying ducks during peak laying period of production (30-38 wks of age).