Schweigert F J, Gottwald C
Institute of Nutritional Science, University of Potsdam, Bergholz-Rehbrücke, Germany.
Equine Vet J. 1999 Jul;31(4):319-23. doi: 10.1111/j.2042-3306.1999.tb03824.x.
The objective of this study was to investigate in mares the effect of parturition on plasma and milk levels of retinol, beta-carotene, alpha-tocopherol and cholesterol over 12 weeks around parturition. In blood plasma of horses around parturition an increase of all these components was observed. This increase was most impressive in beta-carotene (P<0.05) and less pronounced for vitamin E, vitamin A and cholesterol. The magnitude of increase around parturition corresponded well with the magnitude of accumulation in colostrum; levels of beta-carotene in colostrum were 65 times higher compared to mature milk while vitamin A, vitamin E and cholesterol were only 3 to 8 times higher. Beta-carotene concentrations in colostrum were positively correlated with corresponding plasma levels (r = 0.9; P<0.001). Reasons for the increase in plasma beta-carotene around parturition may include an improved absorption of carotene and/or reduced conversion into vitamin A as well as mobilisation from tissue storages or a reduced uptake in tissues other than the mammary gland. In conclusion, the results may point to possible component- and species-specific differences involved in the transfer of fat-soluble vitamins, beta-carotene and cholesterol from blood plasma into colostrum.
本研究的目的是调查母马分娩对分娩前后12周血浆和乳汁中视黄醇、β-胡萝卜素、α-生育酚和胆固醇水平的影响。在临近分娩的马的血浆中，观察到所有这些成分都有所增加。这种增加在β-胡萝卜素中最为明显（P<0.05），而维生素E、维生素A和胆固醇的增加则不太明显。分娩前后的增加幅度与初乳中的积累幅度非常吻合；初乳中β-胡萝卜素的水平比成熟乳汁高65倍，而维生素A、维生素E和胆固醇仅高3至8倍。初乳中的β-胡萝卜素浓度与相应的血浆水平呈正相关（r = 0.9；P<0.001）。分娩前后血浆β-胡萝卜素增加的原因可能包括胡萝卜素吸收改善和/或向维生素A的转化减少，以及从组织储存中动员或乳腺以外组织的摄取减少。总之，结果可能表明在将脂溶性维生素、β-胡萝卜素和胆固醇从血浆转移到初乳中存在可能的成分和物种特异性差异。
