Efeito do nível de proteína bruta na ração sobre indicadores de termorregulação de codornas europeias em crescimento

Abstract

A total of 720 quails (Coturnix coturnix coturnix) with 14 days of age were used, with 360 quails (180 males and 180 elaborated) from each strain. To evaluate the effects of crude protein levels in the growth diets on cloacal and surface temperature, as well as heat loss by radiation in meat quails of two strains, at different ages. The birds of each sex were distributed in a completely randomized design in a 5x2 factorial scheme, five levels of protein in the diet (17, 19.5, 22, 24.5 and 27%) and two strains (A and B), with three replicates of 12 quails per unit experimental. The thermoregulation indicators obtained were: cloaca temperature, surface temperature and heat loss by radiation. Statistical analysis of data from males and females were analyzed separately and tested for the effects of crude protein levels, strains and breeding period. In the result of males there was no significant interaction between the studied factors. However, the increase in the level of crude protein in the diets significantly influenced the cloacal temperature of the birds, which showed an increasing linear behavior. On the other hand, there was a difference between strains, where surface temperature and heat loss by radiation were statistically higher in strain B birds. However, the increase in the level of crude protein in the diets significantly influenced the cloacal temperature of the birds, which showed an increasing linear behavior. On the other hand, there was a difference between strains, where surface temperature and heat loss by radiation were statistically higher in strain B birds. When comparing the females of the two strains, it was observed that the cloaca temperature and heat loss by radiation were statistically higher in the birds of strain B. In turn, the age of the quail influenced all parameters, where the advance of the age of the birds reduced surface temperature and increased cloacal temperature and heat loss by radiation. It was concluded that, regardless of strain and age, the increase in crude protein content in rations from 17 to 27% increased the cloacal temperature of the quails, while, regardless of the protein level, quails from the higher weight strain, as well as advancing the age from the third to the fifth week of age resulted in greater heat loss by radiation.