Abstract: This study was carried out to investigate, the relationships among chick hatching weight, egg weight and egg weight loss during preincubation storage period in Japanese quail. Correlation coefficients between chick hatching weight and egg weight, egg weight loss during 4 days preincubation period were determined as 0.47 (p<0.01) and 0.36 (p<0.01). Highly positive correlations among egg weight loss groups were determined (p<0.01).

INTRODUCTION

Influence of the traits related with egg on hatchery practice is considerably important issue (Inal et al., 1996; Erensayin, 2000). Egg weight range in Japanese quails was reported to be between 8.31 and 13.00 g (Ariturk et al., 1980; Havenstein et al., 1988). Shanawany (1987) determined that quail chick weight was 66.9% of the egg weight and existence of positive correlation 0.994, between chick hatching weight and egg weight. Altan et al. (1995) reported positive correlation between chick hatching weight and egg weight ranging from 0.57-0.80.

Egg weight loss in heavy eggs of average 11.20 g in preincubation and incubation period was higher than that of lighter eggs of average 9.54 g (Peebles and Marks, 1991).

Both preincubation and incubation period egg weight losses have been resulting in a decrease in hatchability percentage and an increase in problems related with hatchery and chick quality.

The aim of this study was to investigate, the relationships among chick hatching weight, egg weight and egg weight losses during storage period in Japanese quail.

MATERIALS AND METHODS

In this study, 160 chicks obtained from 160 fertile eggs have been used. Eggs collected were maintained at 14-15°C storage room condition. Eggs were weighed daily for 10 days for determining egg weight losses. Chicks were weighed at the hatching time. Besides computing correlation coefficient among traits, a regression equation was fitted using chick hatching weight as dependent variable and preincubation period egg weight losses and hatching egg weight as explanatory variable by using stepwise regression procedure. SPSS 15.0 (2006) packet program was used for statistical analysis.

RESULTS AND DISCUSSION

Hatching egg weight, chick hatching weight and egg weight loss was given in Table 1. Relationships among hatching egg weight, chick hatching weight and egg weight loss were given in Table 2. Regression and determination coefficients to be used for predicting chick hatching weight were given in Table 3 and 4.

Results of present study indicating average hatching egg weight of 11.29 g was higher than the values observed by Nestor and Bacon (1982), Darden and Marks (1988), Marks (1991) and similar to findings of Peebles and Marks (1991) and Vilchez et al. (1991).

Table 1:	Chick Hatching Weight (CHW), Hatching Egg Weight (HEW), Preincubation period Egg Weight Loss (EWL) average (g) and standard error (mean±SE) (n = 160)

Table 2:	Correlation coefficients and their level of significance among Chick Hatching Weight (CHW), Hatching Egg Weight (HEW), preincubation period Egg Weight Loss (EWL)
**p<0.01

Table 3:	Regression coefficients, standard errors and significance level of explanatory variables for predicting chick hatching weight

Table 4:	Determination coefficients (R2) and standard error

Proportion of chick weight to egg weight, 66.9%, agrees with result of Shanawany (1987). Although, Shanawany (1987) and Altan et al. (1995) reported positive linear correlation between hatching egg weight and chick hatching weight to be 0.994 and 0.57-0.80, respectively, in this study it was estimated as 0.47 (p<0.01). In the present study, significant positive linear correlation between chick hatching weight and egg weight loss resulted from 4 day storage of eggs was found as 0.36 (p<0.01) and positive high degree correlations among egg weight loss except for 4 and 8 days egg weight loss group was statistically significant (p<0.01) (Table 2).

Executing stepwise regression procedure, a regression equation of 0.86 R² for predicting chick hatching weight was fitted by using egg weight loss and hatching egg weight as explanatory variable.

Regression equation was given: