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Milk yield by Saanen Goats: relationship between stress, apoptose, cortisol and IGF-I

Grant number: 16/00123-3
Support type:Regular Research Grants
Duration: May 01, 2016 - April 30, 2017
Field of knowledge:Agronomical Sciences - Animal Husbandry - Animal Production
Principal Investigator:João Alberto Negrão
Grantee:João Alberto Negrão
Home Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil


Milk yield in Saanen goats: relationships between stress, cortisol, IGF-I and apoptosis.The increase in milk yield is related to number and activity of epithelial cells. Consequently, the decline in milk production after peak lactation occurs due to a decrease in the secretion activity of epithelial cells, and reduction in the numbers of these cells by apoptosis. It seems that greater lactation persistence might be achieved by an increase in the cell survival rate. However, stress can increase metabolic rate via cortisol and could increase the process of oxidation, apoptosis rate and reduce lactation persistence. At the same time, it is postulated that IGF-I increase the proliferation of epithelial cells, and increase milk synthesis and persistency of lactation. In this context, it is important to study the effect of cortisol and IGF-I in epithelial cells in vivo (study I) and in vitro (study II). To attempt this goal, experimental goats will be study during all lactation and submit at two experiments: in vivo (Experiment I) and in vitro (Experiment II). In vivo, experimental goats will receive ACTH, GH, ACTH-GH treatment or Placebo solution. Afterwards, epithelial cells of these goats will be maintain in vitro and submit to different cortisol (0, 10, 100 e 1000 ¼g/mL) and IGF-I (0, 10, 100 e 1000 ng/mL) concentrations. During all lactation, milk yield and milk quality (microbiological, physical and chemical characteristics) will be measured. At 60, 90 120 and 150 days of lactation and blood samples and biopsy of the mammary tissue will be samples for analysis of cortisol, IGF-I, DNA, RNA, PCNA, TUNEL, IGF-I, IGF-R, IGFBP3 e IGFBP5. In fact, this project propose to study productive, physiological and molecular responses of Saanen goats to cortisol and IGF-I, and their influence in apoptosis of epithelial cells and lactation persistence in vivo and in vitro.Key-words: Lactation, mammary gland, milk synthesis, epithelial cells, persistency. (AU)

Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
HOOPER, H. B.; SILVA, P. DOS S.; DE OLIVEIRA, S. A.; MERINGHE, G. K. F.; LACASSE, P.; NEGRAO, J. A. Effect of heat stress in late gestation on subsequent lactation performance and mammary cell gene expression of Saanen goats. JOURNAL OF DAIRY SCIENCE, v. 103, n. 2, p. 1982-1992, FEB 2020. Web of Science Citations: 0.
HOOPER, HENRIQUE BARBOSA; SILVA, PRISCILA DOS SANTOS; DE OLIVEIRA, SANDRA APARECIDA; FONSECA MERIGHE, GIOVANA KREMPEL; NEGRAO, JOAO ALBERTO. Acute heat stress induces changes in physiological and cellular responses in Saanen goats. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY, v. 62, n. 12, p. 2257-2265, DEC 2018. Web of Science Citations: 2.
BOMFIM, G. F.; MERIGHE, G. K. F.; DE OLIVEIRA, S. A.; NEGRAO, J. A. Effect of acute stressors, adrenocorticotropic hormone administration, and cortisol release on milk yield, the expression of key genes, proliferation, and apoptosis in goat mammary epithelial cells. JOURNAL OF DAIRY SCIENCE, v. 101, n. 7, p. 6486-6496, JUL 2018. Web of Science Citations: 5.

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