Journal article

Publication year: 2015

Pages: 7328-7334

Journal: Journal of Dairy Science

Volume number: 98

Issue number: 10

ISSN: 0022-0302

Open access status: Bronze

DOI Link: https://doi.org/10.3168/jds.2014-9218

Publisher: Elsevier

Abstract: 
Conjugated linoleic acids (CLA) are well known as milk fat-reducing feed supplements in diets for lactating ruminants. However, their effects on milk concentrations of fat-soluble vitamins are unknown. This study was performed to investigate the hypothesis that CLA affect the concentrations of retinol and tocopherol in ewe milk. For that purpose, group-housed Merino ewes (101 +/- 13.7 kg) nursing twin lambs and fed with a hay:concentrate diet were supplemented with either 45 g of a rumen-protected CLA supplement containing 3.4 g of cis-9,trans-11-CLA and 3.4 g of trans-10,cis-12-CLA (CLA group, n = 11) or with 45 g of a hydrogenated vegetable fat (control group, n = 12) per ewe per day during the first 6 wk of lactation. Feed intake was recorded daily (concentrate) or weekly (hay) per group. Milk spot samples were collected at the beginning of the experiment (5 +/- 2.4 d postpartum) and then weekly after lambs had been separated for 2 h from their mothers. The milk fat content was determined and feed and milk were analyzed for concentrations of alpha-, gamma-, and gamma-tocopherol and for retinol by HPLC. Dietary intake of tocopherol and retinol was similar in both groups. Feeding CLA decreased milk fat concentration by 23% on average, and during the first 3 wk of the study milk tocopherol concentration tended to be increased by feeding CLA (+17%), but retinol concentrations were not influenced. When related to milk fat, CLA feeding significantly increased both milk tocopherol (+40%) and retinol (+32%) and these effects were evident during the whole experimental period corresponding to the first half of lactation.

Harvard Citation style: Zeitz, J., Most, E. and Eder, K. (2015) Effect of conjugated linoleic acid on concentrations of fat-soluble vitamins in milk of lactating ewes, Journal of Dairy Science, 98(10), pp. 7328-7334. https://doi.org/10.3168/jds.2014-9218

APA Citation style: Zeitz, J., Most, E., & Eder, K. (2015). Effect of conjugated linoleic acid on concentrations of fat-soluble vitamins in milk of lactating ewes. Journal of Dairy Science. 98(10), 7328-7334. https://doi.org/10.3168/jds.2014-9218