Effect of experimental stress and cortisol release induced by ACTH administration on expression of key genes related to milk synthesis and apoptosis during mammary involution of Saanen goats

• Published in: Journal of dairy research 2022-11, Vol.89 (4), p.404-409
• Main Authors: Manica, Emanuel, Silva, Priscila dos Santos, Merighe, Giovana Krempel Fonseca, de Oliveira, Sandra Aparecida, Bomfim, Gabriela Facholi, Negrão, João Alberto
• Format: Article
• Language: English
• Subjects: 1-Phosphatidylinositol 3-kinase; Adrenocorticotropic hormone; Adrenocorticotropic Hormone - pharmacology; AKT protein; AKT1 protein; Animals; Apoptosis; Biopsy; Casein; Cell survival; Cortisol; Experiments; Feeds; Female; Gene expression; Genes; Goats; Goats - physiology; Growth factors; Hormones; Hydrocortisone; Immune system; Insulin; Kinases; Lactalbumin; Lactation - physiology; Lactoferrin; Lactoferrin - genetics; Leukocytes; Mammary gland; Mammary glands; Mammary Glands, Animal - metabolism; Milk; Milk - metabolism; Milk production; Rapamycin; Secretions; Synthesis; TOR protein
• ISSN: 0022-0299; 1469-7629
• DOI: 10.1017/S0022029922000735

This research paper addresses the hypothesis that stress, induced by ACTH administration and cortisol release increases somatic cell count (SCC) in mammary secretion, and improves the effectiveness of dry off in goats. We report indicators of milk synthesis and mammary gland involution during dry off. Thirty Saanen goats were subjected to abrupt dry off and treatments: (1) ACTH administration (ACTH) or (2) placebo (Control) on days 1, 3, 6, 9, 12, 15, 30, and 60 of dry off. The expression of target genes in mammary tissue that are related to milk synthesis and cell survival such as insulin-like growth factor 1 receptor (IGF1R), phosphatidylinositol-3-kinase (PIK3CA), protein kinase B (AKT1) and mechanistic target of rapamycin (MTOR), casein (CSN2), lactalbumin (LALBA) and lactoferrin (LF) were evaluated, and plasma cortisol concentration, SCC, leucocyte count, and microbiological analyses in milk and mammary secretions were assessed. ACTH significantly downregulated the expression of IGF1R and upregulated the expression of PIK3CA in mammary tissue, increased lactoferrin concentration and SCC, and changed immune cell levels in mammary secretions compared to Control. Furthermore, ACTH administration increased the percentage of dry goats compared to the Control (73 vs. 46%, respectively). We conclude that the effect of stress via ACTH administration and cortisol release accelerated mammary involution during the early dry-off period.