PHYSIOLOGICAL PARAMETERS AND THERMAL COMFORT INDICES OF LAYERS FED VEGETABLE GLYCERIN
T. L. de Sena2*, S. C. Bastos-Leite1, A. M. de Vasconcelos1, C. de C. Goulart1, M. R. S. de Farias2 and J. de S. Maranguape2
1Department of Animal Science - Center for Agrarian and Biological Sciences, State University of Vale do Acaraú, Ceará, Brazil; 2Post-graduate Program in Animal Science, State University of Vale do Acaraú, Ceará, Brazil
*Corresponding Author’s Email: thaissena_19@hotmail.com
ABSTRACT
The aim of this study was to evaluate the physiological parameters and thermal comfort indices of commercial layers fed diets containing different levels of vegetable glycerin. A total of 378 Hy-Line White layers at 32 weeks of age were housed in a shed at nine birds per cage. The experiment lasted 84 days. Treatments consisted of a control diet (without glycerin) plus five diets with increasing levels of vegetable glycerin (3, 6, 9, 12, and 15%). The black globe humidity index (BGHI) and radiant heat load (RHL) were out of the thermal comfort zone and were higher in the afternoon period in all production cycles. Respiratory frequency was lower in the morning, when 3% glycerin were added to the diet. The surface temperatures of comb, wattle, back, wings, head, and feet did not differ with the glycerin levels and were higher in the 2nd cycle, but within the range recommended for the species. Glycerin inclusion levels of up to 12% can be used to partially replace corn in diets for layers housed in sheds covered with ceramic tiles without compromising their thermoregulation in a hot environment.
Keywords: Alternative Feeds. Homeothermy. Poultry Farming. Thermal Environment.
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