Comparison of Milk Fat Globule Membrane (MFGM) proteins in milk samples of Chianina and Holstein cattle breeds across three lactation phases through 2D IEF SDS PAGE - A preliminary study

BackgroundCharacterisation and identification of proteins involved in milk production are important to understand the biology of lactation and to manage dairy cattle selection. Many studies have investigated mammary function, milk secretion and mammary gland involution, but the critical molecular mechanisms implicated are still incomplete. We focused on Milk Fat Globule Membranes (MFGM), a unique subcategory of proteins mainly originating from the Golgi apparatus and endoplasmic reticulum of mammary gland cells.MethodsUsing a proteomic approach, 2D-IEF SDS PAGE and ESI MS/MS we compared milk MFGM belonging to Chianina and Holstein cattle breeds, representative of selection for meat and milk traits, respectively.ResultsThe two breeds showed different trends in the amount of structural proteins and proteins related to lipid droplet formation, as well as in immunity-related molecules, MFG secretion, mammary gland epithelium apoptosis and mammary gland involution.ConclusionsWe successfully isolated the major MFGM proteins and monitored their differences between the two breeds, among three different lactation phases and within the same breed across the lactation phases. The detected differences were relative to the amount of proteins involved in lipid deposition into the droplets, immune system and mammary gland cell apoptosis.

Highlights► We compared milk MFGM belonging to Chianina and Holstein cattle. ► Analyses were performed through 2D-electrophoresis at 3 different lactation phases. ► Differential proteins were involved in lipid droplet formation. ► Immunity-related molecules, MFG secretion and apoptosis pathways were also altered.