Transcriptional regulation of acetyl-CoA carboxylase α isoforms in dairy ewes during conjugated linoleic acid induced milk fat depression

• Published in: Animal (Cambridge, England) England), 2016-10, Vol.10 (10), p.1677-1683
• Main Authors: Ticiani, E., Urio, M., Ferreira, R., Harvatine, K. J., De Oliveira, D. E.
• Format: Article
• Language: English
• Subjects: Acetyl-CoA Carboxylase - genetics; Acetyl-CoA Carboxylase - metabolism; Adipose Tissue - metabolism; Animals; Dairying; Diet - veterinary; Dietary Supplements; Female; gene expression; Gene Expression Regulation - drug effects; Glycolipids - metabolism; Glycoproteins - metabolism; lactating ewe; Lactation; Linoleic Acids, Conjugated - pharmacology; Lipogenesis - drug effects; Mammary Glands, Animal - metabolism; Milk - chemistry; Milk - metabolism; milk fat depression; Nutrition; Organ Specificity; Promoter Regions, Genetic - genetics; Protein Isoforms; Research Article; Sheep - genetics; Sheep - physiology
• ISSN: 1751-7311; 1751-732X
• DOI: 10.1017/S1751731116000677

Feeding trans-10, cis-12 CLA to lactating ewes reduces milk fat by down-regulating expression of enzymes involved in lipid synthesis in the mammary gland and increases adipose tissue lipogenesis. Acetyl-CoA carboxylase α (ACC-α) is a key regulated enzyme in de novo fatty acid synthesis and is decreased by CLA. In the ovine, the ACC-α gene is expressed from three tissue-specific promoters (PI, PII and PIII). This study evaluated promoter-specific ACC-α expression in mammary and adipose tissue of lactating cross-bred Lacaune/Texel ewes during milk fat depression induced by rumen-unprotected trans-10, cis-12 CLA supplement. In all, 12 ewes arranged in a completely randomized design were fed during early, mid and late lactation one of the following treatments for 14 days: Control (forage+0.9 kg of concentrate on a dry matter basis) and CLA (forage+0.9 kg of concentrate+27 g/day of CLA (29.9% trans-10, cis-12)). Mammary gland and adipose tissue biopsies were taken on day 14 for gene expression analysis by real-time PCR. Milk fat yield and concentration were reduced with CLA supplementation by 27%, 21% and 35% and 28%, 26% and 42% during early, mid and late lactation, respectively. Overall, our results suggest that trans-10, cis-12 CLA down-regulates mammary ACC-α gene expression by decreasing expression from PII and PIII in mammary gland and up-regulates adipose ACC-α gene expression by increasing expression from PI.