Banca de DEFESA: LUCAS DE ALMEIDA SILVA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : LUCAS DE ALMEIDA SILVA
DATE: 30/07/2020
TIME: 14:00
LOCAL: INSTITUTO DE ZOOTECNIA
TITLE:

Effect of Zearalenone on the reproductive tract of Nellore heifers..

KEY WORDS:

Cattle, Confinement, Estradiol, Mycotoxins, Reproduction.

PAGES: 26
BIG AREA: Ciências Agrárias
AREA: Zootecnia
SUBÁREA: Produção Animal
SUMMARY:

SILVA, Lucas de Almeida. Effect of Zearalenone on the reproductive tract of Nellore heifers.. 2020. 18p Master Thesis (Master of Science in Animal Science, Animal Production). Instituto de Zootecnia, Universidade Federal Rural do Rio de Janeiro, Seropédica, RJ, 2020. The aim of the present study was to evaluate the effects of eating a diet contaminated with Zearalenone (ZEA) on the morphometry of the reproductive system and plasma estrogen concentration in heifers. Twenty non-pregnant, healthy Nellore heifers (Bos taurus indicus), aged ≥18 months, average initial body weight (BW) around 350kg were used, receiving a diet composed of 70% roughage and 30% concentrate, with based on dry matter (DM) in confinement. Two treatments were evaluated: 1) control (without contamination), and 2) diet contaminated with ± 300 ppb of ZEA. The contamination was carried out daily via addition and mixing to the concentrate and then to the roughage in the trough. The experiment had a total duration of 88 days, with 13 days of adaptation period. Every week, all females were evaluated by rectal palpation and ultrasound examination. The evaluation of the uterus was performed by measuring the diameter of the right and left horn, after cross sectioning immediately after the uterine bifurcation. Two measurements of the largest diameters of each horn cut were made and the average was calculated. The right and left ovaries were also evaluated according to their diameter, from the average of the two largest ovarian diameters, the diameters of antral follicles and corpus luteum were also checked. The size of the vulva was measured using a caliper, according to the final third up to the glabrous ends. Five mL of blood from the coccygeal vein were collected weekly in heparinized tubes for estrogen measurement (E2). E2 concentration was determined by radioimmunoassay (RIA). A completely randomized design was adopted, with effect of time. Each animal was considered an experimental unit (10 per treatment, n = 20). Analysis of variance (p <0.05) was performed using the “R” software. The effect of time was evaluated using regression models, considering the polynomial of the highest significant degree. The measurement of the vulvas was not influenced by the treatments (p = 0.0985), as well as the diameter of the uterine horns (p = 0.0522). The average diameter of the ovaries (p = 0.6955), follicles (p = 0.6355) and corpus luteum (p = 0.3808) were also not influenced by the intake of ZEA. The dosage of estrogen was also not influenced by the treatments (p = 0.3379). No follicular cysts, lutein cysts, vaginal discharge or abnormal estrous behavior were observed during weekly evaluations or daily management. The results of the present study indicate that the contamination with 300ppb of ZEA in the diet of Nellore heifers did not influence the morphometric parameters of the reproductive system evaluated, nor the plasma estrogen dosage.

BANKING MEMBERS:
Externa à Instituição - THAYS CRISTINA OLIVEIRA DE QUADROS - OUTRO
Interno - 3055881 - ALEX LOPES DA SILVA
Presidente - 2316004 - RONDINELI PAVEZZI BARBERO