title: The effect of long term under- and over-feeding on the expression of genes related to lipid metabolism in mammary tissue of sheep.
abstract: Milk fatty acid (FA) synthesis by the mammary gland involves expression of a large number of genes whose nutritional regulation remains poorly defined. In this study, we examined the effect of long-term under- and over-feeding on the expression of genes (acetyl Co A carboxylase, ACC; fatty acid synthetase, FAS; lipoprotein lipase, LPL; stearoyl Co A desaturase, SCD; peroxisome proliferator activated receptor γ2, PPARγ2; sterol regulatory element binding protein-1, SREBP-1c; and hormone sensitive lipase, HSL) related to FA metabolism in sheep mammary tissue (MT). Twenty-four lactating sheep were divided into three homogenous sub-groups and fed the same ration in quantities covering 70% (underfeeding), 100% (control) and 130% (overfeeding) of their energy and crude protein requirements. The results showed a significant reduction of mRNA of ACC, FAS, LPL and SCD in the MT of underfed sheep, and a significant increase on the mRNA of LPL and SREBP-1c in the MT of overfed compared with the control respectively. In conclusion, the negative, compared to positive, energy balance in sheep down-regulates ACC, FAS, LPL, SCD, SREBP-1c and PPARγ2 expression in their MT which indicates that the decrease in nutrient availability may lead to lower rates of lipid synthesis.
authors.affiliation: Department of Nutritional Physiology and Feeding,Agricultural University of Athens,Iera Odos 75, GR-11855,Athens,Greece.
authors.forename: Eleni
authors.initials: E
authors.lastname: Tsiplakou
authors.affiliation: Department of Agricultural Biotechnology,Agricultural University of Athens,Iera Odos 75, GR-11855,Athens,Greece.
authors.forename: Emmanouil
authors.initials: E
authors.lastname: Flemetakis
authors.affiliation: Department of Agricultural Biotechnology,Agricultural University of Athens,Iera Odos 75, GR-11855,Athens,Greece.
authors.forename: Evangelia-Diamanto
authors.initials: ED
authors.lastname: Kouri
authors.affiliation: Department of Mathematics and Statistics,Agricultural University of Athens,Iera Odos 75, GR-11855,Athens,Greece.
authors.forename: Kyriaki
authors.initials: K
authors.lastname: Sotirakoglou
authors.affiliation: Department of Nutritional Physiology and Feeding,Agricultural University of Athens,Iera Odos 75, GR-11855,Athens,Greece.
authors.forename: George
authors.initials: G
authors.lastname: Zervas
mesh_terms: D000103:Acetyl-CoA Carboxylase / Q000235:genetics; D000821:Animal Feed; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D004032:Diet / Q000662:veterinary*; D015536:Down-Regulation / Q000502:physiology; D002149:Energy Intake; D004734:Energy Metabolism; D064429:Fatty Acid Synthases / Q000235:genetics; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D015870:Gene Expression / Q000502:physiology*; D007774:Lactation; D050356:Lipid Metabolism / Q000235:genetics*; D050155:Lipogenesis / Q000235:genetics; D008071:Lipoprotein Lipase / Q000235:genetics; D008321:Mammary Glands, Animal / Q000378:metabolism*; D009751:Nutritional Requirements; D047495:PPAR gamma / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D012756:Sheep / Q000235:genetics / Q000378:metabolism*; D013230:Stearoyl-CoA Desaturase / Q000235:genetics; D051780:Sterol Regulatory Element Binding Protein 1 / Q000235:genetics
chemical_list: D005227:Fatty Acids; D047495:PPAR gamma; D012333:RNA, Messenger; D051780:Sterol Regulatory Element Binding Protein 1; D013230:Stearoyl-CoA Desaturase; D064429:Fatty Acid Synthases; D008071:Lipoprotein Lipase; D000103:Acetyl-CoA Carboxylase
keywords: Underfeeding; lipogenic gene; overfeeding; sheep