Genetic and phenotypic relationships between the fear and some performance trai̇ts in japanese quai̇l

Fear is one of the important factors that cause economic losses affect occurrence of stress in poultry. Tonic immobility, which is one of the most important criteria of the fear situation in poultry, is a reaction that restricts the movement in animal for a short time. In this study, it was aimed to determine the genetic and phenotypic relationships between the use of Japanese quail, which is considered to be a model animal for both commercially important and other poultry animals, and the heritability of the fear level and other yield characteristics. In the study, 400 quail obtained from a breeder flock consisted of 42 males and 126 females, which have not been subjected to any selection studies before, were used. The quail were weighed and attached the wing number. In hatch weekly live weights were measured individually, and tonic immobility measurements were made in the fifth and sixth weeks. Individual growth analyzes were performed using the Gompertz nonlinear regression model using weekly live weight values. All quails were sent to slaughter at the age of six weeks. Carcass, edible internal organs, abdominal fat, breast, leg, wing and back-neck weights were measured in slaughter. The live weight averages of the quail from the hatch to the sixth week of slaughter were 7.33, 15.16, 28.70, 49.23, 70.35, 91.04 and 115.24 g, respectively. Tonic immobility averages measured at the fifth and sixth weeks of quail were determined as 81.84 sec and 87.54 sec. Averages of Gompertz growth curve model parameters (β0, β1, β2) were found to be 265.78, 3.92, 0.046, respectively, and the inflection point age and weight of the model were 35.06 days and 97.78 g, respectively. The averages of hot carcass, gizzard, heart, liver, abdominal fat and edible internal organ weights of quail were found as 82.75, 2.89, 1.12, 2.49, 1.27, 6.50 g, respectively. Cold carcass, breast, leg, wing and back-neck weights were found to be 86.29, 32.94, 19.79, 6.15, 25.64 g, respectively. In the study, the heritability levels for all traits were estimated by single and multi-trait methods, and the heritability levels estimated by the multi-trait method were much higher. The heritability levels of tonic immobility characteristics measured at the fifth and sixth weeks were ranged 0.01 to 0.05 with the single-trait method; low level were estimated between 0.11 and 0.21 by multi-trait method. Estimated heritabilities for weekly live weights and parameters of the Gompertz model are high. For the weight values of the slaughter-carcass characteristics, medium-high and low-medium level heritabilities were estimated. Genetic and phenotypic relationships between tonic immobility measurements and all yield characteristics were found to be low and generally statistically insignificant. Heritabilities related to tonic immobility characteristics were estimated by single and multivariate statistical methods and were found to be between 0.01 and 0.20 at low levels. The genetic relationships of the tonic immobility trait with other yield characteristics are also estimated to be low (-0.19-0.20). In a poultry breeding study, in which the improvement of the level of fear is also taken into account, since the mentioned trait has a low level of heritability and it is associated with other yield characteristics and it is found that the innocuous trait directly in the selection indexes. As a result, it is understood that a breeding study to be carried out in order to improve the level of fear in poultry should be carried out using long-term and many characteristics. KEYWORDS: Fear, Genetic correlation, Inheritance, Tonic immobility, Quail