Trocas de calor e desempenho de codornas japonesas confinadas em ambiente termoneutro e sob estresse térmico.

Abstract

The production of Japanese quail (Coturnix coturnix japonica) has been gaining prominence in the national scenario compared to other livestock production already consolidated within the poultry agroindustrial system, mainly in the last two decades. This growth has aroused the attention and interest of researchers in the development of works that contribute to the improvement and fixation of coturniculture as an even more profitable exploration in commercial production. Within these lines of research, highlight the welfare of birds in breeding environments and heat exchanges, since the understanding of the birds' physiological responses to climatic variations is a preponderant factor in order to seek high productivity indexes. The objective of this work was to evaluate the heat exchanges and productive performance of Japanese laying quails, housed in environments with controlled bioclimatic conditions, under conditions of comfort and stress. In this sense, this research was developed in a climatic chamber using 30 Japanese quail in peak posture, housed in mini-chambers equipped with feeder, drinkers and waste collection system. The animals were submitted to three temperatures (20, 26 and 32 oC), and two air velocities (0.5 and 2.0 m s-1), maintaining the relative humidity of the air constant at 65%. Egg quality, ingestion and physiological parameters of the birds were evaluated. For the heat exchanges, the transfers by radiation and convection, besides the enthalpy of the air and the rate of mixing ratio, were analyzed. The results indicated that the environments with 20 oC and 2.0 m s-1 and 32 oC and 0.5 m s-1 confer inadequate conditions for the production of Japanese laying quails; Already for the ingestive behavior, there was a greater demand for water by the birds with the increase of the temperature, and a decrease in the food intake. The physiological and thermodynamic parameters presented increasing values according to the elevation of the air temperature, unlike the length of waves emitted by the birds, which presented an inversely proportional behavior. The heat exchange by radiation was much lower when compared to the loss by convection.