The effect of long term under- and over-feeding on the expression of six major milk protein genes in the mammary tissue of sheep.

Milk protein synthesis in the mammary gland involves expression of six major milk protein genes whose nutritional regulation remains poorly defined. In this study, the effect of long term under- and over-feeding on the expression of αs1-casein: CSN1S1, αs2-casein: CSN1S2, β-casein: CSN2, κ-casein: CSN3, α-lactalbumin: LALBA and β-lactoglobulin: BLG gene in sheep mammary tissue (MT) was examined. Twenty-four lactating dairy sheep, at 90-98 d in milk, were divided into three groups and fed the same ration, for 60 d, in quantities which met 70% (underfeeding), 100% (control) and 130% (overfeeding) of their energy and crude protein requirements.

The effect of long term under- and over-feeding on the expression of genes related to glucose metabolism in mammary tissue of sheep.

Glucose utilisation for lactose synthesis in the mammary gland involves expression of a large number of genes whose nutritional regulation remains poorly defined. In this study, the effect of long term under- and over-feeding on the expression of genes [glucose transporter 1: GLUT1, glucose transporter 3: GLUT3, Sodium glucose contransporter 1: SGLT1, two isoforms of β- (1,4) galactosyltransferase: β- (1,4) GAT1, β- (1,4) GAT3 and α-lactalbumin: LALBA] related to glucose metabolism in sheep mammary tissue (MT) was examined. Twenty-four lactating dairy sheep were divided into three homogenous sub-groups and fed the same ration in quantities which met 70% (underfeeding), 100% (control) and 130% (overfeeding) of their energy and crude protein requirements.

The effect of long term under- and over-feeding on the expression of genes related to lipid metabolism in mammary tissue of sheep.

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.