Dietary vitamin D3 requirement of magang goslings from 1–21 days of age

Abstract

The present study was conducted to investigate the effect of dietary vitamin D3 levels (0, 200, 400, 800, 1600, and 3200 IU/kg) on growth performance, calcium-phosphorus metabolism, and tibia development of goslings from 1 to 21 days of age. A total of 720 one-day-old Magang male goslings with similar initial body weight were randomly divided into 6 treatments with 6 replicates per treatment and 20 geese per replicate. The goslings fed with 400 IU vitamin D3/kg of diet obtained the maximum average daily gain, while vitamin D3 supplementation significantly improved the feed/gain of goslings aged from 1 to 21 days (P < 0.05). The vitamin D3 requirement of gosling aged from 1 to 21 days for optimal feed/gain ratio and average daily gain were estimated from three regression models (one-slope straight, two-slope straight, and quadratic broken-line model) to be 246–352 IU/kg diet and 400–518 IU/kg diet, respectively. Serum calcium and phosphorus contents, parathyroid hormone level, and 25-hydroxycholecalciferol level responded to increasing dietary vitamin D3 levels (P < 0.05) and reached a plateau at 800, 0, and 200 IU vitamin D3/kg diet, respectively. The mRNA expressions of target genes related to calcium homeostasis such as vitamin D3 receptor, Na+/Ca2+ exchanger 1, and plasma membrane calcium ATPase 1b in the duodenum and kidney (P < 0.05) and parathyroid hormone receptor mRNA expression in the kidney (P < 0.05) were increased linearly and quadratically with the increasing dietary vitamin D3 levels, respectively. Graded doses of dietary vitamin D3 from 0 to 3200 IU/kg produced linear responses in tibial density (P < 0.05). The vitamin D3 requirement of gosling aged from 1 to 21 days ranged from 519 to 698 IU/kg diet when tibial density as an evaluation criterion. In conclusion, the vitamin D3 requirement of gosling aged from 1 to 21 days for optimal growth performance (feed/gain and average daily gain) and tibial density was estimated to be 246–352 IU/kg of diet, 400–518 IU/kg of diet, and 519–698 IU/kg of diet based on three regression models (one-slope straight, two-slope straight, and quadratic broken-line model), respectively. The most appropriate vitamin D3 requirement was recommended at 602 IU/kg of diet of young geese based on the mean estimated values of three regression models for the tibial density with the highest coefficient of determination and lowest mean square error.