Banca de DEFESA: GIANCARLO PEREIRA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: GIANCARLO PEREIRA SILVA
DATA: 23/09/2026
HORA: 15:00
LOCAL: Online via GoogleMeet
TÍTULO:

IMPACTS OF INCREASING LEVELS OF N-CARBAMYLGLUTAMATE IN BEEF CATTLE DIETS

PALAVRAS-CHAVES:

Arginina, bovinos, nitrogênio, sustentabilidade, ureia

PÁGINAS: 60
GRANDE ÁREA: Ciências Agrárias
ÁREA: Zootecnia
SUBÁREA: Nutrição e Alimentação Animal
ESPECIALIDADE: Avaliação de Alimentos para Animais
RESUMO:

This study aimed to evaluate the effects of N-carbamoylglutamate (NCG) inclusion in diets with high or low concentrate inclusion on intake, nutrient digestibility, nitrogen (N) metabolism, ruminal fermentation, and kinetics in beef heifers. Eight rumen-cannulated Tabapuã heifers (initial body weight ± SD; 350 ± 70 kg) were used in two simultaneous 4 × 4 Latin squares. Each Latin square received one of two diets with high or low forage inclusion (80:20 and 20:80 forage-to-concentrate ratios, respectively), and four levels of NCG were evaluated within each Latin square: 0, 20, 40, and 60 mg/kg of body weight. Nutrient intake and digestibility, ruminal fermentation parameters, microbial protein synthesis (MCP), N excretion routes, and blood metabolite profiles were assessed. Overall, NCG effects were independent of the diets, except for serine and creatine, which were greater for NCG + high concentrate (P = 0.01 and P = 0.04, respectively). Intake and digestibility were not affected by NCG (P > 0.010). No linear or quadratic effects of NCG supplementation or diet × NCG interaction were detected for microbial protein synthesis (PMIC), microbial organic matter digested (MOD), or bacterial crude protein (BCP) (P > 0.20). However, diet significantly affected MOD (P < 0.0001) and BCP (P < 0.001), with greater values observed in animals fed the high-concentrate diet. NCG did not affect microbial synthesis or excretion (P > 0.20 and P > 0.43, respectively). In contrast, linear effects of NCG supplementation were observed for N retention (P < 0.05), N-use efficiency (% of N intake; P < 0.04), and N-use efficiency (apparent absorbed N; P < 0.02). Linear effects of NCG supplementation tended to occur for threonine (P = 0.09) and nonessential amino acids (NEAAs; P = 0.10), whereas linear effects were detected for proline (P < 0.02), tyrosine (P < 0.03), leucine (P < 0.05), phenylalanine (P < 0.01), tryptophan (P < 0.03), and essential amino acids (EAAs; P < 0.03). A quadratic effect of NCG supplementation was detected for methionine (P < 0.04). Significant diet × NCG interactions were observed for creatine (P < 0.01), L-threonine (P < 0.05), and L-serine (P < 0.04), with a tendency for β-hydroxybutyric acid (P = 0.09). Diet affected formate (P < 0.001), and a tendency was observed for L-phenylalanine (P = 0.08), with greater values in the high-concentrate diet. No linear effects of NCG supplementation were detected for the evaluated variables (P > 0.16); however, quadratic effects were observed for creatine (P < 0.001), L-phenylalanine (P < 0.02), L-lysine (P < 0.05), and methionine (P < 0.02), with tendencies for D-glucose (P = 0.07) and valine (P = 0.06). Contrary to our hypothesis, NCG did not affect sites of digestion, nutrient intake, ruminal passage rate, fermentation, or microbial synthesis. However, N retention and N efficiency were greater when NCG was included in the diet, accompanied by increased concentrations of EAAs, whereas NEAA concentrations tended to increase. This difference in the metabolic profile suggests differences in the rate or site of N availability, resulting in greater N utilization efficiency in beef cattle and suggesting an opportunity to improve animal performance.

MEMBROS DA BANCA:
Presidente - ERICK DARLISSON BATISTA (Membro)
Externo à Instituição - EVAN TITGEMEYER - KU (Membro)
Externo à Instituição - MARCIO DE SOUZA DUARTE - nd (Membro)
Interno - MARINA DE ARRUDA CAMARGO DANES (Membro)
Interno - MATEUS PIES GIONBELLI (Suplente)
Externo à Instituição - VINÍCIUS CARNEIRO DE SOUZA - UCDavis (Suplente)