Banca de QUALIFICAÇÃO: LETÍCIA RODRIGUES FARIA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: LETÍCIA RODRIGUES FARIA
DATA: 15/08/2022
HORA: 08:30
LOCAL: Sala do Programa de Pós-graduação em Zootecnia
TÍTULO:

Productive performance, metabolic profile and oocyte quality of dairy cows fed canola meal replacing soybean meal

PALAVRAS-CHAVES:

 

Dietary protein, nitrogen, methionine, oocyte apoptosis.

PÁGINAS: null
GRANDE ÁREA: Ciências Agrárias
ÁREA: Zootecnia
SUBÁREA: Produção Animal
RESUMO:

Feeding canola meal can improve milk and protein yields, and nitrogen utilization efficiency by dairy cows when replacing soybean meal. The use of canola meal in diets could reduce blood and follicular fluid urea nitrogen concentrations, which in high concentrations are detrimental to the oocyte. Furthermore, canola meal is a protein source rich in methionine, which can affect positively oocyte development and metabolism. Thus, feeding canola meal could improve oocyte quality of dairy cows when replacing soybean meal. The objective of this study will be to evaluate the productive performance, metabolic profile and oocyte quality in dairy cows receiving canola meal replacing soybean meal. Thirty multiparous cows will be used and blocked by parity, milk production in previous lactation, expected date of calving and body condition score. The animals will receive the same diet varying only the protein source: (I) diet with soybean meal (control, n = 15) and (II) diet with canola meal (n = 15), provided from calving until 70 days in milk. Diets will be formulated to be isoproteic (15% crude protein) and isoenergetic. Diets will be adjusted weekly to maintain the same proportions of dry matter and crude protein. Dry matter intake will be measured daily throughout the experiment. The animals will be weighed and evaluated for the body condition score on the calving day and on the last day of each experimental week. Milk production and components will be determined in the last 2 days of weeks 1, 3, 5 and 7 postpartum. Spot samples of urine and feces will be collected in the week before of expected date of calving and on the last day of weeks 1, 3, 5 and 7 postpartum at 6 h before and 6 h after feeding. Based on the creatinine analysis, the volume of daily excretion of urine will be determined. The purine derivatives will be used to estimate microbial protein production. Blood samples will be collected in the week before of expected date of calving and on the last day of weeks 1, 3, 5 and 7 postpartum at 0, 2, 4, 8 and 12 h after feeding. Blood samples will be analyzed to methionine, glucose, urea, β-hydroxy-butyrate, insulin and insulin-like growth factor 1 (IGF-1) concentrations. The indigestible neutral detergent fiber will be used as an internal marker to estimate fecal production and apparent digestibility of nutrients in the total tract. The balance and the nitrogen utilization efficiency will be calculated. Follicular wave emergence will be synchronized on day 40 of lactation for aspiration of cumulus oophorus complexes (COCs) and collection of dominant follicle fluid. The COCs will be matured in vitro and evaluated for nuclear maturation, apoptosis and gene expression related to oocyte development and metabolism. In the dominant follicle fluid, the concentrations of glucose, urea, ammonia, β-hydroxy-butyrate, insulin and IGF-I will be quantified. Statistical significance will be considered with P≤0.05. It is expected that replacing soybean meal with canola meal will increase milk and protein yields, and improve nitrogen utilization efficiency in dairy cows. Furthermore, it is expected that replacing soybean meal with canola meal will reduce blood and follicular fluid urea nitrogen concentrations, and increasethe blood and follicular fluid methionine content improving oocyte quality of dairy cows. 

MEMBROS DA BANCA:
Presidente - ERICK DARLISSON BATISTA (Membro)
Externo à Instituição - GUILHERME DE PAULA NOGUEIRA - UNESP (Membro)
Interno - MARINA DE ARRUDA CAMARGO DANES (Membro)
Externo ao Programa - MILLER PEREIRA PALHAO - DMV/FZMV (Membro)
Externo à Instituição - ÁLAN MAIA BORGES - UFMG (Suplente)