Banca de DEFESA: ANDREY DE SOUSA MIRANDA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: ANDREY DE SOUSA MIRANDA
DATA: 08/06/2026
HORA: 09:00
LOCAL: Online
TÍTULO:

The effect of vitamin a injection in pregnant beef cows on maternal physiology and recruitment of cells for adipogenesis in offspring muscle tissue

PALAVRAS-CHAVES:

Adipogenesis, Gene expression, Marbling, Retinoic acid.

PÁGINAS: 77
GRANDE ÁREA: Ciências Agrárias
ÁREA: Zootecnia
RESUMO:

The objective of this study was to evaluate the effects of vitamin A injection in pregnant Tabapuã cows during late gestation on maternal performance and metabolism, subsequent lactation, and offspring skeletal muscle gene expression at birth and weaning. The experiment was conducted over two years using 41 purebred Bos indicus (Tabapuã) pregnant cows. At 245 days of gestation, cows were blocked by parity and assigned to one of two treatments: control with no vitamin A injection (CON, n = 21; 13 male and 8 female fetuses) or vitamin A injections (VA, n = 20; 12 male and 8 female fetuses). Cows in the VA group received intramuscular injections of vitamin A (2,700,000 IU) on days 245, 260, and 275 of gestation. Animals were fed a high-forage basal diet and managed under grazing conditions after calving. Data were analyzed using the MIXED procedure of SAS in a randomized complete block design with a 2 × 2 factorial arrangement (treatment × offspring sex). At 275 days of gestation, CON cows tended to have greater body weight (P = 0.09), and total gain of gestational components also tended to be greater in CON cows (P = 0.09). Cows carrying male fetuses exhibited greater (P ≤ 0.05) gestational gain and placental weight. Placental gene expression was modulated by treatment in a sex-dependent manner, with increased expression of STRA6 (P = 0.04) in VA cows carrying female fetuses, while VEGFA and SLC5A1 were more highly expressed (P ≤ 0.03) in placentas of female fetuses. No treatment effects were observed on cow body weight or average daily gain from calving to weaning (P > 0.36). During lactation, VA-treated cows nursing male calves produced more milk (P = 0.02) and had higher milk fat and protein contents (P ≤ 0.03) compared to other groups. In the offspring, birth weight was reduced (P = 0.05) in VA females compared to counterparts, while males showed greater (P ≤ 0.05) average daily gain and weaning weight. Skeletal muscle gene expression at birth was influenced by treatment and offspring sex, with upregulation of CEBPα and MYOG in VA calves (P ≤ 0.09) and significant treatment × sex interactions for CEBPα, PAX7, and MYF5. Male calves exhibited greater expression of MYOG (P < 0.01), while females tended to show greater ZNF423 expression (P = 0.08). At weaning, calves from VA-treated cows showed improved muscling traits, with a 19% greater muscling index (P = 0.01) and a tendency for greater longissimus muscle width (P = 0.06). In summary, maternal vitamin A supplementation during late gestation did not markedly improve overall growth performance but modulated placental and muscle gene expression in a sex-dependent manner and enhanced lactation performance and offspring muscle development. These findings suggest that prenatal vitamin A supplementation can influence maternal physiology and fetal programming, potentially improving carcass-related traits in beef cattle.

MEMBROS DA BANCA:
Externo ao Programa - TATHYANE RAMALHO SANTOS GIONBELLI - DZO/FZMV (Suplente)
Externo à Instituição - PRISCILLA DUTRA TEIXEIRA - UFMS (Membro)
Presidente - MATEUS PIES GIONBELLI (Membro)
Interno - MARCIO MACHADO LADEIRA (Membro)
Externo à Instituição - MARCIO DE SOUZA DUARTE - nd (Membro)
Externo à Instituição - KAROLINA BATISTA NASCIMENTO - UFSJ (Membro)
Externo à Instituição - GERMAN DARIO RAMIREZ ZAMUDIO - USP (Suplente)