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Acta Prataculturae Sinica ›› 2026, Vol. 35 ›› Issue (8): 134-143.DOI: 10.11686/cyxb2025334

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Effects of 25-hydroxyvitamin D3 on growth performance and expression of genes related to protein synthesis in muscle of dairy bulls

Hao-dong ZHANG(), Yu-qian JING, Jia-xin FENG, Bai-qiao LIU, Jiang FENG, Nan SUN, Wen-jie HUO, Gang GUO, Qiang LIU(), Cong WANG   

  1. College of Animal Science,Shanxi Agricultural University,Taigu 030801,China
  • Received:2025-08-18 Revised:2025-09-22 Online:2026-08-20 Published:2026-06-22
  • Contact: Qiang LIU

Abstract:

We evaluated the effects of 25-hydroxyvitamin D? (CAL) and coated CAL (CCAL) on the average daily weight gain, nutrient digestibility, rumen fermentation, blood metabolites, and transcript profiles of genes related to protein synthesis in muscle of dairy bulls. Fifty Holstein bulls with (175.6 ± 16.81) kg body weight and (6.0 ± 0.2) months of age were assigned in a randomized block design to five groups with 10 bulls per group. Bulls in the control group received no supplementation, and those in the low CAL (LCAL), high CAL (HCAL), low CCAL (LCCAL), and high CCAL (HCCAL) groups received supplementation of 0.5 or 1.0 mg·d?1 in the form of CAL or CCAL, respectively. The experimental period was 70 days, with 10 days for adaptation. During the data and sample collection period, the body weights of bulls were measured, and samples of feed, feces, ruminal fluid, blood, and muscle were collected. 1) It was found that with increasing CAL or CCAL supplementation, the average daily gain (ADG) increased linearly (P<0.05), and the feed-to-gain ratio decreased linearly (P<0.05). The apparent digestibility of dry matter, organic matter, and neutral detergent fiber increased linearly (P<0.05) with increasing CAL or CCAL supplementation. Ruminal total volatile fatty acid (TVFA) content and molar proportions of isobutyrate and isovalerate increased linearly (P<0.05), but the acetate-to-propionate ratio decreased linearly (P<0.05) with increasing CAL or CCAL supplementation. Blood total protein, albumin, insulin-like growth factor-1 (IGF-1), total antioxidant capacity (T-AOC), glutathione peroxidase (GSH-Px), CAL, and 1,25-dihydroxyvitamin D? increased linearly (P<0.05), but the malondialdehyde content decreased linearly (P<0.05) with increasing CAL or CCAL supplementation. The transcript levels of IGF-1IGF-1RPI3KmTOR, and P70S6K (encoding insulin-like growth factor-1, insulin-like growth factor-1 receptor, phosphatidylinositol 3-kinase, mechanistic target of rapamycin, and ribosomal protein S6 kinase, respectively) in muscle increased linearly (P<0.05) with increasing CAL or CCAL supplementation. 2) Compared with bulls in the CAL groups, those in the CCAL groups had higher ADG, blood T-AOC, GSH-Px, CAL, and 1,25-dihydroxyvitamin D? levels and higher transcript levels of IGF-1IGF-1RPI3KmTOR and P70S6K inmuscle, similar nutrient digestibility and ruminal TVFA contents, but lower feed-to-gain ratio. These results indicate that CCAL is more effective than CAL for increasing the growth performance of bulls and decreasing the feed-to-gain ratio.

Key words: 25-hydroxyvitamin D?, nutrient digestibility, rumen fermentation, antioxidant status, muscle protein synthesis, Holstein bull