Allometric coefficients of major chemical components of meat quail raised in different thermal environments

The objective of the present study was to estimate and compare allometric coefficients of the major chemical components of meat quail raised in different thermal environments, based on protein weight of feather free body (FFB) and feathers. In total, 300 meat quail, males and females, were distributed in a completely randomized design with 2 treatments (climatized environment, 26°C, and non-climatized environment, 29°C) and 6 replicates of 25 birds each. On the first day, 36 birds were selected to form the reference group and from this day on, 2 quail were weekly sampled from each cage. All selected birds were fasted for 24 h, weighed, slaughtered, plucked, and reweighed. The FFB and feathers were ground separately to obtain homogeneous samples, which were freeze-dried to determine the water content, and thereafter, ground again in a micromill before analyzing for protein, lipid, and ash using AOAC procedures. The adjustment of the allometric equations was made using crude protein (CP) weight as the independent variable and water, lipid, and ash weight as the dependent variables. The data of each dependent variable were transformed into natural logarithm (ln), regressed according to lnCP, and subjected to a parallelism test. In the FFB, water showed early development and lipid and ash showed late development in relation to the CP weight. In feathers, water and ash weight showed early development in relation to the feathers protein weight, whereas lipids showed late development. The environments of 26°C and 29°C did not affect the allometric coefficients that described the growth between the chemical components in the body and in the feathers, except for lipids in male FFB, that showed higher allometric coefficient at 29°C than 26°C. Describing the allometric relationships between the major chemical components of meat quail body is an important step in supporting future research comprised modeling of body growth and nutrition for meat quail.