Termografia infravermelho associada à energia metabolizável da ração de poedeiras comerciais

Abstract

To assist in the implementation of feeding strategies and techniques that promote health and animal comfort, new tools have been inserted in animal production, among them the infrared thermography (IRT), an imaging diagnostic technique capable of evaluating the surface temperature distribution. The objective of this work was to evaluate the efficiency of IRT to detect variations in the surface temperatures caused by modifications in the metabolic activity, as a function of the energy content of the commercial hens ration under field conditions. A total of 384 22-week-old Lohmann Lsl-Lite hens, distributed in a completely randomized design, consisting of four treatments and eight replicates of 12 birds each were used. The treatments consisted of diets containing different amounts of metabolizable energy (ME) (2,600, 2,750, 2,900 and 3,050 kcal / kg). The results were submitted to analysis of variance (ANOVA). The split-plot in time scheme was used with three evaluation periods of 21 days each. In cases of significant differences the means were compared by the Tukey test (5%). In the case of a significant effect of the linear polynomial regression of the variables the regression equation was made. Subsequently a simple Pearson correlation was performed between the temperature variables of the birds and the ambient temperature. The energy content studied did not influence the cloacal and superficial temperatures (P> 0.05) or hemogasometry results. There was a positive correlation between air temperature and body, head, leg and eye temperatures (P <0.05). With the increase in the ME content, there was a reduction in feed intake (P <0.05) and improvement in feed conversion by mass and dozen eggs (P <0.05), with linear effect for these variables. With the increase of ME contents of the feed, there was a reduction (P <0.05) in the yolk color and the specific gravity of the eggs. The different energy contents affected (P <0.05) the constituents of the egg. The highest percentage of eggshell was observed in the eggs of the birds that received the rations containing 2,900 and 2,750 kcal ME / kg. Albumin was present in higher proportions in the eggs of the birds that received the highest ME content and the percentage of yolk was higher in the eggs of the birds that received the feed with 2,750 kcal ME / kg. With the use of IRT it was not possible to identify changes in the surface temperatures caused by modifications in the metabolic activity of laying hens fed diets containing different levels of metabolizable energy.