Transcriptional regulation of acetyl-CoA carboxylase α isoforms in dairy ewes during conjugated linoleic acid induced milk fat depression.
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.
1Department of Animal Production,Santa Catarina State University,Lages,Santa Catarina,88520-000,Brazil.
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Ticiani
1Department of Animal Production,Santa Catarina State University,Lages,Santa Catarina,88520-000,Brazil.
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Urio
2Department of Animal Science,Santa Catarina State University,Chapecó,Santa Catarina,89815-630,Brazil.
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Ferreira
3Department of Animal Science,Penn State University,University Park,PA 16802,USA.
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Harvatine
1Department of Animal Production,Santa Catarina State University,Lages,Santa Catarina,88520-000,Brazil.
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De Oliveira
D000103:Acetyl-CoA Carboxylase / Q000235:genetics* / Q000378:metabolism; D000273:Adipose Tissue / Q000378:metabolism; D000818:Animals; D003612:Dairying; D004032:Diet / Q000662:veterinary; D019587:Dietary Supplements; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects*; D006017:Glycolipids / Q000378:metabolism; D006023:Glycoproteins / Q000378:metabolism; D007774:Lactation; D044243:Linoleic Acids, Conjugated / Q000494:pharmacology*; D066292:Lipid Droplets; D050155:Lipogenesis / Q000187:drug effects*; D008321:Mammary Glands, Animal / Q000378:metabolism; D008892:Milk / Q000737:chemistry* / Q000378:metabolism; D009928:Organ Specificity; D011401:Promoter Regions, Genetic / Q000235:genetics; D020033:Protein Isoforms; D012756:Sheep / Q000235:genetics / Q000502:physiology*
D006017:Glycolipids; D006023:Glycoproteins; D044243:Linoleic Acids, Conjugated; D020033:Protein Isoforms; C110367:milk fat globule; D000103:Acetyl-CoA Carboxylase
gene expression; lactating ewe; milk fat depression