Modelagem do crescimento de codornas de corte mantidas em diferentes ambientes térmicos

Abstract

The objective of this study was to describe the growth of meat quails kept in different thermal environments. Three hundred meat quail (Coturnix coturnix coturnix) with one day old were used. The birds were conditioning in two masonry rooms, one of them being acclimated. The birds received artificial heating until 14 days, when they were submitted to treatments (Controlled Environment, 26°C; and Environment Without Control, 29°C) under a completely randomized design, with six replicates in each treatment. Weekly, two birds of each cage were randomly taken, slaughtered and defeathered to obtain the fasting, plucked body and feathers weights (g). Chemical analysis for the determination of water, protein, lipid and ash contents (%) were performed on samples obtained from the plucked body and feathers on each day of slaughter. Growth of protein content was described using the non-linear equation of Gompertz and compared within each sex to verify the effect of temperature of the rearing environment using a test of equality of parameters and identity of non-linear models. The natural logarithms of the contents of the chemical components water, lipids and ashes were regressed against the natural logarithm of the protein contents to obtain the allometric coefficients (b) which were compared by parallelism and coincidence test to verify the effect of the temperature of the rearing environment on the relative growth of the component in relation to the protein. The estimated b values were used to predict the growth rates of the other chemical components as a proportion of the growth rate of the protein. No effect of the ambient temperature on the growth of the female body protein was verified. On the other hand, males reared in an environment without air conditioning presented higher protein content (g) at maturity (47.58 vs 42.17g). There was no effect of temperature on the estimated allometric coefficients for the relative growth of none of the body components of the females, whereas for the males a difference was observed in the relative growth of the lipids with the highest b value observed in the animals kept in an environment without air conditioning (1,223 vs 1.080). There was no effect of the temperature of the breeding environment on the growth pattern of the feather chemical components in either sex. It was concluded that environments with temperature between 26.63 and 29.27°C causes changes in the growth pattern of protein and lipid contents only of meat quails males. The used modeling method is able to estimate the weights of meat quails at different ages