Manipulation of incubation temperature: effects on thermal preference, characteristics of the skin, feather and bone of broilers

• Grant number: 11/24156-4
• Support Opportunities: Regular Research Grants
• Start date: April 01, 2012
• End date: July 31, 2014
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Production
• Principal Investigator: Isabel Cristina Boleli
• Grantee: Isabel Cristina Boleli
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

In the present study will investigate the influence of incubation temperature on the thermal preference post-hatching of broiler chickens and on hormonal characteristics, morphological and physiological in the hatchling and throughout creation. For this, three experiments will be performed. In Experiment 1, fertile eggs of broilers (Cobb ®) will be incubated at 37.5 ° C and 60% RH up to 12 days. From the 13th day of incubation to hatching, two incubators will be maintained at 37.5 ° C, two incubators will have its temperature raised to 39.0 ° C, and two more will have their temperature reduced to 36 ° C. In the pre-and post-hatching shall be assessed the characteristics of egg shells, and, at the outbreak of the bird will analyze the characteristics of the skin, feather and bone, quantification of T3, T4, GH and calcium in the blood, body temperature and expression of Hsp 70 in the thyroid and pituitary. In Experiments 2 and 3, the incubation is carried out as in Experiment 1. In Experiment 2, after the outbreak, will determine the thermoneutral zone of male chicks according to incubation temperature (36 ° C, 37.5 ° C and 39 ° C), which consist of a preference test and a thermal thermal challenge, which will be held on the 1st, 7th, 14th, 21st, 28th and 35th days of life and subsequent days, respectively. In Experiment 3, just after hatching, the male chicks of each treatment incubation (36 ° C, 37.5 ° C and 39 ° C) will be placed in chambers with controlled environment and maintained at three different temperatures: thermoneutral recommended for strain, thermal preference ( determined from the data of Experiment 2) in relation to the hot thermal preference. At 14, 28 and 42 days old will analyze the characteristics of the skin and feather, quantification of T3, T4, GH and calcium in the blood, body temperature and Hsp 70 expression in thyroid and pituitary, and only at 42 days, will be analyzed the characteristics of bone and carcass yield of broilers. The data will be subjected to analysis of variance by General Linear Model procedure (GLM) of SAS ® (SAS Institute, 2002) and in case of a statistically significant difference (p <0.05), averages are compared by Tukey test. (AU)