Hue Do T, Petrovski Kiro, Chen Tong, Williams John L, Bottema Cynthia D K
Davies Livestock Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, SA 5371, Australia; Faculty of Animal Science, Vietnam National University of Agriculture, Trau Quy, Gia Lam, Hanoi, 12406 Vietnam.
Davies Livestock Research Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy Campus, SA 5371, Australia.
J Dairy Sci. 2023 Apr;106(4):2866-2878. doi: 10.3168/jds.2022-22398. Epub 2023 Mar 2.
Bovine colostrum contains a high concentration of immune-related microRNAs (miRNAs) that are packaged in exosomes and are very stable. In this study, 5 immune-related miRNAs (miR-142-5p, miR-150, miR-155, miR-181a, and miR-223) were quantified in dam blood, colostrum, and calf blood using reverse transcription quantitative PCR. Their levels in calf blood after colostrum ingestion were investigated to assess whether miRNAs are transferred from the dam to newborn calves. Three groups of Holstein-Friesian bull calves were bottle-fed 2 L of colostrum or milk from different sources twice per day. The group A calves received colostrum from their own dam and the group B calves were fed foster dam colostrum. Each pair of group A and group B calves were fed identical colostrum from the same milking of the corresponding group A dam for 3 d and then bulk tank milk for 7 d after birth. Group C calves were fed only 2L of "pooled colostrum" from multiple dams d 0 to 4 postpartum, and then fed bulk tank milk thereafter for 7 d after birth. The groups were fed colostrum from different sources and different amounts to assess possible miRNA absorption from the colostrum. All miRNAs were at the highest level in colostrum at d 0 and then decreased rapidly after d 1. The level of miR-150 had the largest decrease from 489 × 106 copies/µL (d 0) to 78 × 106 copies/µL (d 1). MicroRNA-223 and miR-155 were the most abundant in both colostrum and milk. Dam colostrum had significantly higher levels of miR-142-5p, miR-155, and miR-181a than the bulk tank milk. However, only the miR-155 concentration was significantly higher in the dam colostrum than in the pooled colostrum. The concentrations of miRNAs in the colostrum were less than in the cow blood (100- to 1,000-fold less). There was no significant correlation between the level of miRNAs in the dam blood and their colostrum, suggesting that miRNA is synthesized locally by the mammary gland rather than being transferred from the blood. MicroRNA-223 had the highest level in both calf and cow blood compared with the other 4 immune-related miRNAs. Calves were born with high levels of immune-related miRNAs in their blood, and there were no significant differences in miRNA levels between the 3 calf groups at birth or after they were fed different colostrum. This suggests that these miRNAs were not transferred from the colostrum to the newborn calves.
牛初乳含有高浓度的免疫相关微小RNA（miRNA），这些miRNA被包裹在外泌体中且非常稳定。在本研究中，使用逆转录定量PCR对母畜血液、初乳和犊牛血液中的5种免疫相关miRNA（miR-142-5p、miR-150、miR-155、miR-181a和miR-223）进行了定量分析。研究了初乳摄入后犊牛血液中这些miRNA的水平，以评估miRNA是否从母畜转移至新生犊牛。三组荷斯坦-弗里生公牛犊每天两次通过奶瓶喂食2升来自不同来源的初乳或牛奶。A组犊牛食用自身母畜的初乳，B组犊牛喂食寄养母畜的初乳。每对A组和B组犊牛在出生后3天内喂食来自相应A组母畜同一次挤奶的相同初乳，然后在出生后7天内喂食大罐牛奶。C组犊牛在产后0至4天仅喂食来自多只母畜的2升“混合初乳”，之后在出生后7天内喂食大罐牛奶。给各组喂食不同来源和不同量的初乳，以评估初乳中可能的miRNA吸收情况。所有miRNA在第0天的初乳中水平最高，然后在第1天后迅速下降。miR-150的水平从489×10⁶拷贝/微升（第0天）降至78×10⁶拷贝/微升（第1天）时下降幅度最大。MicroRNA-223和miR-155在初乳和牛奶中含量最为丰富。母畜初乳中miR-142-5p、miR-155和miR-181a的水平显著高于大罐牛奶。然而，只有miR-155在母畜初乳中的浓度显著高于混合初乳。初乳中miRNA的浓度低于母牛血液中的浓度（低100至1000倍）。母畜血液中miRNA水平与其初乳中的水平之间无显著相关性，这表明miRNA是由乳腺局部合成而非从血液中转移而来。与其他4种免疫相关miRNA相比，MicroRNA-223在犊牛和母牛血液中的水平最高。犊牛出生时血液中免疫相关miRNA水平较高，且在出生时或喂食不同初乳后，3组犊牛的miRNA水平无显著差异。这表明这些miRNA未从初乳转移至新生犊牛。
