Perda de calor e desempenho de codornas criadas em diferentes densidades e submetidas a dietas com diferentes níveis de óleo de soja

Abstract

Quails are homeothermic animals, in other words, they are able to keep body temperature constant even when variations in ambient temperature occur. In countries with a tropical climate, such as Brazil, birds face difficulties in controlling body temperature inside sheds. Thus, in order to minimize the effects of heat stress, nutritional strategies can be used, where partial replacement of carbohydrates by oil, based on the reduction of the caloric increment of the diet through the use of lipids as a source of energy. Thus, the objective of this study was to evaluate the effect of different densities and inclusion levels of soybean oil on performance and heat loss in quail. To conduct the experiment, 450 quails, 7 days old, housed in a conventional shed divided in 30 boxes were used. The birds were distributed in a completely randomized design (CRD) in a 3x2 factorial scheme, six treatments with five replicates of 14 (215.6 cm².ave-1) and 16 (188.6 cm².ave-1) quails. Inclusion levels of soybean oil were: 0.2, 4%. Environmental data, temperature and relative air humidity as well as physiological data, rectal and surface temperature were collected for six weeks. The loss of heat by radiation was estimated with the aid of infrared thermography. The concentration of ammonia, pH and humidity were evaluated to characterize the quality of beds at 21 and 42 days in order to estimate its influence on the comfort and performance of the birds. During this same period, the temperature of the bed was measured to observe the variation along the boxes. Based on the results, it was found that soybean oil inclusion levels didn’t affect the performance and yield of quails, as well as didn’t influence the loss of heat during the life cycle of these animals. The housing density influenced the feed intake, where the birds raised at the density of 188.6 cm2.ave-1 obtained the lowest average of diet intake, with no impact on weight gain and feed conversion, allowing the creation with larger numbers of birds per box.