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Effects of nutrient restriction on mammary cell turnover and mammary gland remodeling in lactating dairy cows.

Abstract : The aim of this study was to investigate the effects of a severe nutrient restriction on mammary tissue morphology and remodeling, mammary epithelial cell (MEC) turnover and activity, and hormonal status in lactating dairy cows. We used 16 Holstein × Normande crossbred dairy cows, divided into 2 groups submitted to different feeding levels (basal and restricted) from 2 wk before calving to wk 11 postpartum. Restricted-diet cows had lower 11-wk average daily milk yield from calving to slaughter than did basal-diet cows (20.5 vs. 33.5 kg/d). Feed restriction decreased milk fat, protein, and lactose yields. Restriction also led to lower plasma insulin-like growth factor 1 and higher growth hormone concentrations. Restricted-diet cows had lighter mammary glands than did basal-diet cows. The total amount of DNA in the mammary gland and the size of the mammary acini were smaller in the restricted-diet group. Feed restriction had no significant effect on MEC proliferation at the time of slaughter but led to a higher level of apoptosis in the mammary gland. Gelatin zymography highlighted remodeling of the mammary extracellular matrix in restricted-diet cows. Udders from restricted-diet cows showed lower transcript expression of α-lactalbumin and kappa-casein. In conclusion, nutrient restriction resulted in lower milk yield in lactating dairy cows, partly due to modulation of MEC activity and a lower number of mammary cells. An association was found between feed restriction-induced changes in the growth hormone-insulin-like growth factor-1 axis and mammary epithelial cell dynamics.
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Déposant : Céline Martel <>
Soumis le : vendredi 7 septembre 2012 - 15:31:13
Dernière modification le : vendredi 21 août 2020 - 11:20:07

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F. Dessauge, Vanessa Lollivier, B. Ponchon, R. Bruckmaier, L. Finot, et al.. Effects of nutrient restriction on mammary cell turnover and mammary gland remodeling in lactating dairy cows.. Journal of Dairy Science, American Dairy Science Association, 2011, 94 (9), pp.4623-35. ⟨10.3168/jds.2010-4012⟩. ⟨hal-00729290⟩



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