title: Proliferation and apoptosis in subcutaneous adipose tissue of lactating cows with different genetic merit for milk yield.
abstract: The aim of this study was to investigate the adipocyte size and fate in subcutaneous fat (scAT) of cows diverging for genetic merit at mid lactation stage, when anabolic activity increases and animals are in a state of positive energy balance. Twenty mid lactation cows (180±20days in milk) grouped according to the Estimated Breeding Values (EBV) for milk yield in plus (EBVp) and minus (EBVm) variants were selected. Average of adipocytes area, proliferation and apoptotic labelling index as well as DLK-1 expression, a marker of pre-adipocytes, were immunohistochemically evaluated in scAT biopsies. In EBVp cows, the BCS was lower (P<0.01) whereas milk yield, protein, fat yield (P<0.001) and plasma free fatty acid concentration (P<0.05) were higher. The scAT of EBVp cows showed a significantly (P<0.001) higher frequency between 500 and 3000μm2classes in comparison to EBVm cows, that showed a significantly (P<0.01) higher apoptotic labeling index. The immunohistochemical reaction showed DLK-1 positivity in scAT of EBVp cows. Taking together, the data indicate a link between milk yield genetic merit of cows, scAT morphology and function, suggesting greater dynamics and metabolic flexibility in EBVp cows.
authors.affiliation: Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze, 206, 33100 Udine, Italy. Electronic address: monica.colitti@uniud.it.
authors.forename: Monica
authors.initials: M
authors.lastname: Colitti
authors.affiliation: Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze, 206, 33100 Udine, Italy.
authors.forename: Nataliya
authors.initials: N
authors.lastname: Pošćić
authors.affiliation: Department of Agricultural, Food, Environmental and Animal Sciences, University of Udine, via delle Scienze, 206, 33100 Udine, Italy.
authors.forename: Bruno
authors.initials: B
authors.lastname: Stefanon
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D001947:Breeding; D002417:Cattle; D049109:Cell Proliferation / Q000235:genetics*; D004734:Energy Metabolism / Q000235:genetics; D005260:Female; D007774:Lactation / Q000235:genetics* / Q000378:metabolism; D008892:Milk; D050151:Subcutaneous Fat / Q000166:cytology* / Q000378:metabolism
keywords: Adipocytes; Cattle; Genetic merit; Lactation