Banca de QUALIFICAÇÃO: ANDREY DE SOUSA MIRANDA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: ANDREY DE SOUSA MIRANDA
DATA: 04/04/2025
HORA: 14:00
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:

Intramuscular fat, also known as marbling, is one of the main organoleptic attributes of meat, influencing its sensory qualities such as juiciness, tenderness, and flavor. Research has explored ways to enhance marbling, and vitamin A has been proposed as a potential strategy. This study aims to evaluate the effects of vitamin A injections in pregnant Tabapuã cows on maternal metabolism, subsequent lactation, and gene expression in the muscle tissue of their offspring. The experiment will follow a completely randomized design with two treatment groups: cows receiving no vitamin A injections (CON; n = 21) and cows receiving vitamin A injections (VAV; n = 22) at 245, 260, and 275 days of gestation. The cows will be housed in individual pens with access to feed and water. The experimental treatment involves administering vitamin A at three times the maintenance dose (180,000 IU/kg/day), totaling 2,700,000 IU per application for VAV cows at 245 days of gestation. To ensure that vitamin A is the only variable between treatments, all cows will receive the same diet. Blood samples will be collected at 0, 3, 24, 96, and 240 hours after each injection to develop a population pharmacokinetic (PopPK) model for vitamin A quantification using UPLC-MS/MS. Simultaneously, liver biopsies will be conducted to assess gene expression. At calving, cotyledon morphometry will be measured, and samples will be collected for histological analysis and gene expression of nutrient transport markers. During the first seven days postpartum, controlled nursing will be monitored using the weigh-suckle-weigh method, and colostrum samples will be collected to measure serum vitamin A concentration. Milk samples will be taken at 15, 30, 45, 73, and 101 days postpartum to evaluate milk quality parameters. After seven days, cow-calf pairs will be moved to Brachiaria pasture with mineral supplementation. Calves will be weighed and undergo muscle tissue biopsies at birth and weaning (210 days) to analyze gene expression related to adipogenesis, angiogenesis, and retinoic acid receptors. At weaning, ultrasound imaging will be performed to assess muscle mass deposition by measuring the ribeye area. Data will be analyzed using a 2×2 completely randomized design, accounting for treatment and offspring sex as fixed effects, with statistical analysis conducted via the SAS MIXED procedure. Results will be considered significant at P ≤ 0.05.

MEMBROS DA BANCA:
Externo ao Programa - TATHYANE RAMALHO SANTOS GIONBELLI - DZO/FZMV (Membro)
Presidente - MARCIO MACHADO LADEIRA (Membro)
Externo à Instituição - MARCIO DE SOUZA DUARTE - nd (Membro)
Externo ao Programa - IRAIDES FERREIRA FURUSHO GARCIA - DZO/FZMV (Membro)
Interno - DANIEL RUME CASAGRANDE (Suplente)
Externo à Instituição - CLAUDIA BATISTA SAMPAIO - UFV (Suplente)