Banca de DEFESA: GILMARA PINTO LEITE

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : GILMARA PINTO LEITE
DATE: 31/08/2021
TIME: 09:00
LOCAL: Sala virtual
TITLE:

Effect of pregnancy on carcass composition and liver cellularity of Zebu heifers

KEY WORDS:

Heifers; Gestation; Tissue mobilization

PAGES: 40
BIG AREA: Ciências Agrárias
AREA: Zootecnia
SUBÁREA: Produção Animal
SPECIALTY: Criação de Animais
SUMMARY:

This study aimed to investigate possible changes in carcass composition and changes in the concentration of biomolecules in the liver induced by pregnancy. For this purpose, 80 Nellore heifers were used, from three commercial farms, which were raised in tropical pastures and supplemented with mineral mixture. After bleeding, the dentition of the animals was evaluated and those with zero or even two permanent incisors were able to collect samples. For confirmation of pregnancy, the uterus was evaluated, and pregnant heifers were classified into three groups according to fetal size (cm). Measurements were taken using a tape measure from the upper end of the skull to the first coccygeal vertebra. First, fetuses were grouped into: 1) < 16 cm; 2) between 17 and 53 cm; 3) > 54 cm. Then, based on the sizes of the fetuses, the fetal age was estimated using the equation: x = 2.5 (y + 21). Where x = fetal age in days and y = apex length (craniocaudal) in cm. The experiment was carried out in an incomplete block design (as a function of fetal size), considering the batch slaughtered as a block effect, with four treatments and twenty replications, as follows: 1- non-pregnant heifers; 2- pregnant women in the first third; 3- pregnant women in the second third and 4- pregnant women in the third third. For the analysis of the chemical and physical composition of the carcass, the session between the 9th and 11th rib was sampled, desiccation and separation of the components: muscle, fat and bone, which were weighed separately, were performed. Then, it was analyzed for the content of dry matter, mineral matter, crude protein and ether extract. In addition, analyzed liver samples collected immediately after evisceration at random points to obtain the concentration of DNA, RNA and total protein. There was a linear decreasing effect of the ether extract content as a function of the size of the fetus (gestational stage) and with regard to the amount of adipose tissue, a tendency towards a decrease was observed (P=0.010). The proportion of crude protein in the carcass of non-pregnant heifers was lower than that of pregnant heifers in the third third (<0.001), with no effect being verified when analyzing the proportion of muscle among pregnant heifers (P= 0.113). The DNA concentration in the liver linearly increased as a function of the size of the fetus (gestational stage) (P=0.002), however, no effects were observed on the amounts of RNA (P=0.209); protein (P=0.411), as well as the RNA:DNA ratio (P=0.702). Therefore, it is concluded that the lower proportion of ether extract due to the increase in the size of the fetus (gestational stages) associated with a lower proportion of adipose tissue for pregnant heifers in the third third indicates that the heifers mobilized reserve tissues to meet the energy requirements maternal. Furthermore, there is evidence that the liver had to resort to cell proliferation to meet the high metabolic rate required by the matrix through the higher concentration of DNA in the liver cells.

BANKING MEMBERS:
Presidente - 1839209 - DAIANY IRIS GOMES
Externo à Instituição - CLAUDIA BRAGA PEREIRA BENTO - UFVJM
Externa à Instituição - IVANNA MORAES DE OLIVEIRA - UNESP
Externa à Instituição - LUANA MARTA DE ALMEIDA RUFINO - UNIFESSPA