ScholarWorks@경상국립대학교

초록

We hypothesised that hydrogenated fat (HF)-spray-coated beta-carotene (beta C) supplement could be used to increase plasma beta C concentration and conception rates after embryo transfer (ET) in Hanwoo beef cows. In Experiment 1, 12 multiparous Hanwoo cows were fed one of four experimental diets in a triplicate 4 x 4 Latin square design for a 28-day period. Treatments included no beta C addition (control), HF-uncoated beta C (HFu beta C), HF-spray-coated beta C (HF beta C), and HF-spray-coated beta C and vitamin A (HF beta CA). The cows under beta C-supplemented treatments were fed 400 mg/day of beta C, and a daily intake for vitamin A of HF beta CA treatment was 30 000 IU/day as retinyl acetate. Blood was collected on days 0, 26, 27, and 28 to analyse beta C and other metabolite concentrations. In Experiment 2, 199 Hanwoo cows with low fertility were randomly assigned to either control (n = 99) or HF beta C treatments (n = 100) based on the results of Experiment 1. The oestrus of the cows was synchronised for ET. The HF beta C group was fed from 4 weeks before to 4 weeks after ET with a daily intake of 400 mg beta C. Pregnancy for conception rates was diagnosed on day 60 after ET, and blood was collected for beta C concentrations on the day before ET. Supplementing beta C resulted in a high plasma beta C concentration (P < 0.001). Supplementing HF beta C or HF beta CA resulted in higher beta C concentrations than HFu beta C (P < 0.001); however, there was no difference between HF beta C and HF beta CA groups. Plasma retinol concentration was lower in the HF beta CA treatment than in the control and HF beta C groups (P < 0.05). Blood metabolites were unaffected by the treatments. The retinol:beta C ratio was lower in the beta C-supplemented treatments than in the controls, and was lower in HF beta C and HF beta CA than in HFu beta C groups (P < 0.001). Plasma beta C concentration was positively correlated with plasma high-density lipoprotein, low-density lipoprotein, and total cholesterol (P < 0.05). Plasma retinol concentration was negatively associated with plasma protein (P < 0.01), but positively associated with plasma creatinine (P < 0.001) and urea (P < 0.01). Supplementing HF beta C to low-fertility cows resulted in higher plasma beta C concentration (P < 0.001) and conception rates (P = 0.024) than those in the controls. In conclusion, HF beta C had a better bioavailability than HFu beta C, and an increase in conception rates by supplementing HF beta C may be beneficial for producing more calves given the low pregnancy rates of bovine ET in Korea. (C) 2021 The Authors. Published by Elsevier B.V. on behalf of The Animal Consortium. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

키워드