Effect of cyclic heat stress on thyroidal hormones, thyroid histology, and performance of two broiler strains
| Autor: | Cintia Amaral Moraes, Fernanda Heloisa Litz, Luciana Ruggeri Menezes Gotardo, Rodrigo Lemos Olivieri Rodrigues Alves, Mara Regina Bueno de Mattos Nascimento, Aline Monteiro dos Santos, João Paulo Rodrigues Bueno, Otávio Cintra Lemos Olivieri |
|---|---|
| Rok vydání: | 2020 |
| Předmět: |
Thyroid Hormones
Atmospheric Science Triiodothyronine Ecology Health Toxicology and Mutagenesis Thyroid Thyroid Gland Live weight Broiler Histology Serum concentration Biology Heat stress Thyroxine Animal science medicine.anatomical_structure LINHAGENS ANIMAIS medicine Animals Chickens Heat-Shock Response Hormone |
| Zdroj: | Repositório Institucional da USP (Biblioteca Digital da Produção Intelectual) Universidade de São Paulo (USP) instacron:USP |
| Popis: | This study determined thyroid hormone (T3 and T4) serum levels and investigated thyroid gland histology, as well as two broiler strains performance kept at different periods of heat stress. Broilers (560 Cobb Slow™ and 560 Hubbard Flex™) were distributed in control environment (0) reared following the thermal recommendations, and environments 1, 2, and 3 exposed to high temperatures for 1 h, 2 h, and 3 h a day, respectively, from 14 to 42 days old. At 21, 28, 35, and 42 days old, blood samples were collected to determine T3 and T4 serum levels. At 42 days old, thyroid glands were removed for histological analyses. The performance was calculated weekly. T3 levels decreased with age advance, while T4 serum concentration was higher at 42 days old (23.27 nmol L−1) and lower at 28 days old (15.69 nmol L−1). The histological sections revealed that thyroid morphology was well preserved. Live weight was higher in Cobb Slow™ (2.97 kg) than Hubbard Flex™ (2.93 kg) broilers at 42 days old. It is possible to conclude that cyclic heat stress exposure for a 3-h period from 14 to 42 days old did not affect performance, thyroid histology, or T3 and T4 serum levels. Cobb Slow™ broilers had the best live weight values at slaughtering. With increasing age, T3 levels decreased and T4 levels increased for both strains. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|