Improvements in sow productivity have raised questions regarding dietary vitamin D recommendations. The present study aimed to evaluate the effects of the housing system with access to sunlight exposure and supplementation of 25-hydroxicholecalciferol on performance and serum levels of 25(OH)D₃ in sows during gestation and lactation. Sows were distributed in an experimental design with two housing systems: gestation crates or gestation free-range system with external area for sunlight exposure; and two diets: 0 or 50 μg of 25-hydroxicholecalciferol kg⁻¹. The use of 25-hydroxicholecalciferol tended (P = 0.052) to improve total born and influenced (P = 0.046) on number of born alive. Litter weight at birth was also increased (P = 0.01) by 25-hydroxicholecalciferol supplementation; 25-hydroxicholecalciferol supplementation and housing system (free-range with sunlight exposure) tended to increase weaning weight (P = 0.07) and litter daily gain (P = 0.051) during lactation. Exposure to sunlight and 25-hydroxicholecalciferol supplementation increased 25(OH)D₃ serum levels when compared with control treatment during gestation (136.95 vs. 113.92 ng mL⁻¹; P = 0.035) and lactation (120.29 vs. 88.93 ng mL⁻¹; P = 0.026). In conclusion, the association of 25-hydroxicholecalciferol supplementation with exposure to sunlight during gestation improved significantly 25(OH)D₃ serum levels and consequently performance traits in gestation and lactation.

中文翻译：

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自由放养系统和补充 25-羟基胆钙化醇可提高混合胎次母猪的生产性能和血清维生素水平

母猪生产力的提高引发了关于膳食维生素 D 推荐的问题。本研究旨在评估日光照射和补充 25-羟基胆钙化醇的饲养系统对妊娠期和哺乳期母猪生产性能和血清 25(OH)D _{3水平的影响。}母猪分布在具有两种圈养系统的实验设计中：妊娠栏或妊娠自由放养系统，具有外部阳光照射区域；和两种饮食：0 或 50 μg 的 25-羟基胆钙化醇 kg ^-1。25-羟基胆钙化醇的使用倾向于 ( P  = 0.052) 提高总出生率并影响 ( P  = 0.046) 活产数。出生时的窝重也增加了（P  = 0.01) 通过补充 25-羟基胆钙化醇；补充 25-羟基胆钙化醇和饲养系统（阳光照射下的自由放养）倾向于增加 哺乳期间的断奶体重 ( P  = 0.07) 和窝日增重 ( P = 0.051)。与妊娠期（136.95对 113.92 ng mL _-1 ^； P =  0.035）和哺乳期（120.29 对 88.93 ng mL ^-1；P  = 0.026）。总之，在妊娠期间补充 25-羟基胆钙化醇与暴露在阳光下的关联显着改善 25(OH)D₃妊娠期和哺乳期的血清水平以及由此产生的性能特征。