LAUSR

BACKGROUND 25-hydroxycholecalciferol (25OHD3 ) is a new feed additive, which is a potential alternative of vitamin D3 in swine nutrition. The objective of this study was to determine the effects of different doses of 25OHD3 supplementation on performance, immunity, antioxidant capacity, intestinal morphology and bone quality in piglet model. RESULTS As dietary 25OHD3 supplementation increased, average daily gain (ADG) was improved (P < 0.05) quadratically during days 1-14, and tended to be increased (P = 0.06) quadratically during overall period. Increasing 25OHD3 supplementation increased (linear effect, P < 0.05) serum 25OHD3 level and serum glutathione peroxidase (GSH-Px) activity. On day 14, serum immunoglobulin A (IgA) was increased (linear and quadratic effects, P < 0.05) as dietary 25OHD3 supplementation increased. On day 28, serum IgA level was higher (P < 0.05) linearly and complement 3 (C3) level was reduced (P < 0.05) linearly as dietary supplementation of 25OHD3 increased. Mucosal GSH-Px activity of small intestine was higher (quadratic effect, P < 0.05) with increasing 25OHD3 supplementation. Jejunal villus height (P = 0.06) and villus height to crypt depth ratio (P = 0.07) tended to be increased quadratically, as well as villus height to crypt depth ratio of ileum were increased (P < 0.05) linearly and quadratically with increasing 25OHD3 supplementation. In addition, dietary supplementation of increasing level of 25OHD3 increased (quadratic effect, P < 0.05) breaking strength of tibias and femurs. CONCLUSION Increasing dietary 25OHD3 supplementation partly improved performance, immunity, antioxidant status, intestinal morphology, and bone properties of weaned piglets. This article is protected by copyright. All rights reserved.