Banca de DEFESA: ANA CAROLINA OLIVEIRA SANTOS

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE: ANA CAROLINA OLIVEIRA SANTOS
DATA: 26/03/2024
HORA: 14:00
LOCAL: Online via GoogleMeet
TÍTULO:

EFEITOS DO PROCESSAMENTO DO MILHO E DA FONTE DE UREIA NA EXPRESSÃO DE GENES ENVOLVIDOS NO TRANSPORTE DE UREIA, ÁCIDOS GRAXOS VOLÁTEIS E GLICOSE NOS DIFERENTES TECIDOS DE BOVINOS NELORE TERMINADOS EM CONFINAMENTO

PALAVRAS-CHAVES:

excretion, feedlot, gene expression, rehydrated corn, nitrogen

PÁGINAS: 35
GRANDE ÁREA: Ciências Agrárias
ÁREA: Zootecnia
SUBÁREA: Nutrição e Alimentação Animal
ESPECIALIDADE: Avaliação de Alimentos para Animais
RESUMO:

The objective of the study was to evaluate the interaction of urea sources associated with corn processing on the expression of genes related to urea, glucose, volatile fatty acids transport, ruminal pH maintenance, as well as genes related to the urea cycle in the liver in different tissues of finishing Nelore steers. The four treatments consisted of 1) ground corn and conventional urea (GC+CU), 2) ground corn and post-ruminal release urea (GC+PRU), 3) rehydrated corn and conventional urea (RC+CU), and 4) rehydrated corn and post-ruminal release urea (RC+PRU). The period was 100 days. The diet consisted of 28% corn silage (DM), 63% corn (ground or rehydrated), 6.3% soybean meal, 0.1% ammonium sulfate, and 3% a vitamin-mineral supplement and monensin. At 100 days of confinement, the animals were slaughtered, and samples from the rumen, jejunum, kidneys, and liver were collected for gene expression analysis using the RT-qPCR technique and enzymatic activity. Performance variables and nitrogen balance showed no interactions (P ≥ 0.25). Bulls fed rehydrated corn (RC) had higher final weight, average daily gain, feed efficiency, and carcass gains (P < 0.05). Cattle fed ground corn (GC) had higher nitrogen intake (P = 0.04), but fecal nitrogen excretion was higher (P < 0.01), while urinary nitrogen excretion tended to be higher (P = 0.08). This resulted in lower nitrogen retention compared to those receiving rehydrated corn, and nitrogen use efficiency relative to absorbed nitrogen was reduced by 15% (P < 0.01). Similarly, the inclusion of post-ruminal release urea (PRU) in the diet increased final body weight, average daily gain, and feed efficiency (P < 0.01). Due to higher urinary nitrogen excretion in bulls receiving CRU-based diets (P = 0.02), fecal intake and excretion were similar (P > 0.15), resulting in lower nitrogen retention and nitrogen use efficiency (P < 0.01). In the rumen, there was an interaction between GC x PRU for the AE2 and GPR41 genes when bulls consumed GC, the expression of these genes was increased, and this effect was potentiated when PRU was included (P = 0.01). AQP7 was more expressed when animals were fed GC (P = 0.04), which was also observed for TRPV3 (P = 0.007) In the jejunum, the AQP3 and AQP10 genes were more expressed when animals consumed REC (P ≤ 0.04), while AQP7 and ARG1 tended to have higher expression (P ≤ 0.09). The RhCG gene tended to increase its expression when bulls consumed PRU (P = 0.07). In the liver, the CPS1 gene increased its expression when animals consumed RC (P = 0.02), and there was a tendency to increase ASL1 mRNA expression (P = 0.09). In the kidneys, UT-B mRNA was higher when bulls consumed PRU (P = 0.001). In the pancreas, when animals consumed CRU, the corn processing method affected the α-amylase activity, increasing the activity when RC was provided (P = 0.0001). For chymotrypsin, when bulls consumed PRU, the inclusion of RC increased the activity of the enzyme (P < 0.0001). In the jejunum, animals that consumed CRU had increased urease activity when GC was included (P = 0.03), and bulls that received GC also increased urease activity (P < 0.001). For maltase, when PRU was provided, RC was able to increase the activity of this enzyme (P = 0.004). Finally, amylase had higher activity when animals received PRU (P = 0.02). Given the presented facts, it becomes evident that the use of rehydrated corn and PRU (coated Urea) were able to improve the performance of the bulls without altering CMS (Dry Matter Intake). Furthermore, it is clear that the genes involved in urea transport, VFA (volatile fatty acids), and glucose respond differently to the processing method of corn and urea source administered.

MEMBROS DA BANCA:
Externo à Instituição - OTÁVIO RODRIGUES MACHADO NETO - UNESP (Suplente)
Externo à Instituição - MARCIO DE SOUZA DUARTE - nd (Membro)
Externo ao Programa - PRISCILLA DUTRA TEIXEIRA - DZO/FZMV (Suplente)
Interno - MARCIO MACHADO LADEIRA (Membro)
Presidente - ERICK DARLISSON BATISTA (Membro)