External and internal egg quality characteristics in Japanese quails of different plumage color lines

WFL Publisher Science and Technology Meri-Rastilantie 3 B, FI-00980 Helsinki, Finland e-mail: info@world-food.net Journal of Food, Agriculture & Environment Vol.9 (2): 375-379. 2011 www.world-food.net External and internal egg quality characteristics in Japanese quails of different plumage color lines * Alper Yılmaz, Cafer Tepeli and Tamer Çağlayan Department of Animal Science, Faculty of Veterinary Medicine, University of Selcuk, Alaaddin Keykubat Kampüs, Konya, 42003, Turkey. *e-mail: ayilmaz@selcuk.edu.tr Received 20 January 2011, accepted 9 April 2011. Abstract The present study was conducted to determine the external and internal egg quality characteristics in Japanese quails (Coturnix coturnix japonica) of different plumage color lines. A total of 150 eggs obtained from Japanese quails of different plumage color lines at 20 weeks of age were used in the study. The eggs were randomly gathered from same age quails with brown, gray and white plumages. The eggs were examined for external and internal quality characteristics. Concerning the external quality characteristics, there were statistical differences regarding shape index (%) and shell (%) among the different plumage color lines (P<0.01, P<0.05). Of the internal quality characteristics, the differences among plumage color lines in yolk weight(g), albumen weight (g), yolk (%), albumen (%), yolk/albumen (%), albumen index (%) and haugh units were statistically significant (P<0.01). It was also found that there were statistically significant phenotypic correlations with respect to some egg quality traits in the different plumage color lines. According to the findings of the study, the fact that the haugh unit observed in the quail group with brown plumage was higher compared to the other plumage color lines brings into mind the idea that it could be more convenient to offer the eggs in the brown group for consumption as human food. In addition, knowing the significant differences among the different plumage color lines in different quality characteristics will be useful in assisting prospective studies on quail lines. Key words: Egg quality, external, internal, characteristics, correlations, plumage color, quail, lines. Introduction The increase in quail production observed since the 1990s has also caused an increase in the number of studies conducted on the topic in Turkey 3, 20. The fact that quail is a model fowl for other poultry species has increased its use as an experimental material in research studies. Egg production and sale is very important in quail breeding. For this reason, a number of studies have been conducted on egg quality 1, 7, 8, 18. The concept of egg quality brings the external and internal quality characteristics into mind. External and internal quality characteristics of eggs have also 1, 2, 11, 13, 14, 19, 21, 22, 27- been investigated in several studies on quails 29. It was stated in several previous genetic researches 12, 15, 16 that certain genes have an effect on plumage color and there were significant differences among the body weights, abdominal fat levels and egg weights of quails of different plumage colour lines. Studies conducted on the external and internal quality characteristics of eggs from quails of different plumage color lines have not been encountered in literature. However, several findings regarding incubation and growth on quails of different plumage color lines 6, 30 show that it is also necessary to examine the external and internal quality characteristics of quail eggs. The purpose of this study was to determine the external and internal quality characteristics of eggs obtained from quails of different plumage color lines and to present relationships between mentioned characteristics. Furthermore, it will be possible for enterprises dealing in quail production to perform the production and efficiency calculations more accurately with the help of the findings of the present research regarding the egg quality characteristics of quails of different plumage color lines produced in those enterprises. It is also considered that this study will provide information that will assist the prospective studies to be conducted on increasing efficiency by forming quail lines. Materials and Methods The research was conducted in a private enterprise in Konya province. The enterprise housed approximately 6000 quails. In this farm, different plumage color quails were raised in different cages according to plumage colors for commercial and hobby sales. Quails with three different plumage colors (brown, gray and white) at 20 weeks of age were used as the research material. These birds were purchased from three area hobby breeders, each specialized in a different color. The plumage color groups were selected because they were most common in the market. These plumage color groups had been color bred for many genens although the hobby breeders did not keep pedigree information on their flocks. The selected quails were placed in egg laying cages with dimensions of 45 cm x 93 cm x 27 cm (width x length x height). These egg laying cages were exactly the same for all stages of breeding. In addition, in all stages of breeding, different colored quails were grouped in different cages. The 3-floor cage had three egg laying cages on each floor with a total of 9 cages. In this research only 3 egg laying cages on 3 floors were used. Quails were placed in the egg laying cages in a way that there would be 6 males and 24 females of each color group in each floor. So, 18 males and 72 females were settled in three floors for each plumage color group. The birds were fed a diet containing 200 g/kg CP (crude protein) and 2800 kcal/kg ME and provided with fresh water ad libitum through nipple water delivery systems. The study was conducted on randomly selected eggs, Journal of Food, Agriculture & Environment, Vol.9 (2), April 2011 375

every 50 of which were obtained from quails of different plumage color lines. The weighing of the eggs was performed by using a digital display scale with an accuracy of 0.01 g. The width and length of the eggs were measured by a digital display caliper with an accuracy of 0.01 mm. The selected eggs were broken on a table with a glass cover in order to determine the internal quality characteristics. A 3-legged micrometer with an accuracy of 0.01 mm was used for measuring the heights of yolk and albumen, and a micrometer with an accuracy of 0.01 mm was used for measuring the shell thickness. The following formulas were used to determine the external and internal quality characteristics of the eggs 1, 18. Egg weight (g): The eggs were weighed separately. Shell weight (g): After the eggs were broken, egg shells were washed with water and dried in order to clean the remaining albumen. Following this procedure, shell weight (with membrane) was measured. Shell thickness (mm): Shell thickness (with membrane) was measured at the sharp poles, blunt poles and equatorial parts of each egg. Average shell thickness was obtained from the average values of these three parts. weight (g) = Egg weight (Shell weight + weight). Shape index (%) = [Egg width (mm) / Egg length (mm)] x 100 (%) = ( weight(g) / Egg weight(g)) x 100 (%) = ( weight(g) / Egg weight(g)) x 100 / albumen (%): was weighed after being separated from the broken eggs. Shell (%) = (Shell weight(g) / Egg weight(g)) x 100 index (%) = [ height (mm) / diameter (mm)] x 100 index (%) = [ height(mm)/{( length(mm) + width(mm)) /2}] x 100 Haugh unit = 100 log [ height (mm) + 7.57 1.7 x Egg weight(g) 0.37 ] Table 1. External quality characteristics of eggs (mean+s. E.) obtained from quails of different plumage color lines. Characteristics General P (n=50) (n=50) (n=50) (n=150) Egg weight (g) 12.58±0.18 b 13.11±0.13 a 11.90±0.13 c 12.50±0.09 *** Shape index (%) 79.34±0.47 a 77.59±0.44 b 77.16±0.27 b 77.89±0.23 ** Egg width (mm) 26.35±0.12 a 26.43±0.11 a 25.69±0.11 b 26.16±0.07 *** Egg length (mm) 33.22±0.26 b 34.06±0.18 a 33.30±0.17 b 33.54±0.12 *** Shell weight (g) 0.69±0.02 0.70±0.01 0.69±0.01 0.69±0.01 - Shell (%) 5.50±0.19 ab 5.31±0.09 b 5.76±0.09 a 5.53±0.07 * Shell thickness (mm) 0.23±0.002 0.23±0.002 0.23±0.003 0.23±0.002 - a, b, c: The differences among the values bearing different letters on the same line are significant. *** P<0.001 ** P<0.01 * P<0.05 - P>0.05. Table 2. Internal quality characteristics of eggs (mean+s. E.) obtained from quails of different plumage color lines. Characteristics General P (n=50) (n=50) (n=50) (n=150) weight (g) 3.99±0.05 b 4.38±0.06 a 3.89±0.06 b 4.09±0.03 *** weight (g) 7.90±0.13 a 8.04±0.08 a 7.32±0.07 b 7.73±0.06 *** (%) 31.77±0.28 b 33.35±0.26 a 32.66±0.25 a 32.66±0.16 *** (%) 62.73±0.37 a 61.34±0.26 b 61.58±0.27 b 61.81±0.17 ** /albumen (%) 50.82±0.74 b 54.51±0.66 a 53.20±0.64 a 53.01±0.41 ** index 44.89±0.50 44.16±0.35 43.89±0.30 44.25±0.22 - index 11.28±0.31 a 9.38±0.15 b 9.43±0.19 b 9.91±0.14 *** Haugh unit 87.41±0.63 a 83.83±0.28 b 83.60±0.41 b 84.70±0.28 *** a, b: The differences among the values bearing different letters on the same line are significant. *** P<0.001 ** P<0.01 - P>0.05. The one-way variance analysis was used to analyze the egg characteristics among the different plumage color groups. The differences among the groups were determined by Duncan s test. The analyses were performed by using the SPSS 10.0 25 package software programme. The case effect was taken into considen in statistical calculations. Results and Discussion The mean values of external and internal quality characteristics of eggs obtained from quails of different plumage color lines are presented in Tables 1 and 2 and the phenotypic correlations among external and internal quality characteristics of eggs in Tables 3 and 4. Correlations among the internal quality characteristics of eggs obtained from quails of different plumage color lines are at different levels (Table 4). It has been stated in several studies 1, 10, 29 that egg weight increases with hen age and weight, and this increase has an effect on hatching chick weight and hatchability. In addition, a significant level of change was observed in body weight, abdominal fat and egg weight depending on a mutation in plumage color 12. In the present study, the findings that show significant differences among certain external quality characteristics of eggs obtained from quails with different plumage color lines support the results presented in the studies mentioned above. As a matter of fact, hatching yields reported by Çağlayan and Yılmaz 6 and the relationships among egg weight, shape index and hatching chick weight found by Yılmaz and Çağlayan 30 suggest that this relationship could be related to external and internal quality characteristics of eggs obtained from quails of different plumage color lines. Çağlayan and Yılmaz 6 reported that hatching yield and hatchability were highest in eggs from quails of white plumage line, while fertility and embryonic death were highest in eggs from quails of brown plumage line. The mean increase in live weight was highest in gray plumage line quails of 1-6 weeks of age and survival rate highest in brown plumage line quails of 6 weeks of age. For the reported periods, white and brown groups were similar in terms of live weight, and survival rate was lowest in quails in the white group. However, the haugh unit, a quality criterion in this study, was highest in eggs from the quails of brown plumage line. This finding does not contradict Narushin and Romanov 17, that many of the physical characteristics of the egg play a significant role in a good embryo development and a successful hatching. The average values observed especially in egg weight and porosity and values above the average shell thickness and shape index indicate that the egg content is suitable for incubation. 376 Journal of Food, Agriculture & Environment, Vol.9 (2), April 2011

Table 3. Phenotypic correlations among certain external quality characteristics of eggs obtained from quails of different plumage color lines. Plumage color groups External egg quality characteristics Egg weight Egg width Egg length Shape index Shell thickness Shell weight ***: P<0.001 **: P<0.01 *: P<0.05. Egg width Egg length Shape index Shell thickness Shell weight Shell 0.938*** 0.850*** 0.958*** 0.899*** 0.702*** 0.845*** 0.719*** 0.240 0.692*** -0.505-0.043-0.079-0.201 0.479*** 0.176-0.825*** -0.737*** -0.588*** -0.221 0.030-0.672*** -0.083-0.011-0.585** -0.365* -0.027-0.688** 0.342* 0.004 0.656** 0.272 0.311* 0.495*** 0.396** 0.250 0.524*** 0.009 0.242 0.356** 0.318* -0.050 0.111 0.451** 0.338-0.167-0.148-0.241-0.110 0.013-0.225-0.049-0.376* -0.140-0.170 0.551*** -0.036 0.187 0.487** 0.354 0.336 0.909*** 0.846*** 0.806*** In the present study, however, no significant difference was found between shell thickness values, while the highest shell was obtained in the white group. It is considered that this significant difference will affect the hatching results. In fact, it was reported by Çağlayan and Yılmaz 6 that the best hatching results and the lowest embryonic death rates were observed in the eggs of white plumage line quails. It can be said that the haugh unit cannot be a criterion alone for a successful hatching. However, a high haugh unit is a significant criterion in the market for use in cooking egg sector 4, 23. Different studies 5, 16, 24, 26 have shown significant differences in albumen and yolk s and dry matter contents in various species of poultry in lines of different genetic structures and commercial hybrids and these differences were caused by genetic variation. In the present study, the variations observed in the internal quality characteristics of eggs from quails of different plumage color lines bring to mind the possibility of a genetic development in quails of different plumage color lines. The significant differences observed in the internal quality characteristics of eggs in the present study are consistent with the findings mentioned above. The results on quails 7, 8, 11, 18, 19, 27, 28 regarding external and internal quality characteristics appear to be generally consistent with the findings of the present research obtained from the eggs of different plumage color lines quails. However, a detailed examination and comparison shows that there are certain similarities among the external and internal quality characteristics of eggs obtained from quails of different plumage color lines 7, 8, 19, 21, 22 as well as certain differences 2, 11, 14, 18, 27, 28. For example, of the internal quality characteristics, the mean egg weights measured in the present study were higher than the values found in some studies 2, 7, 14, 18, 19, 22, 27, 28 however, they were found to be similar to the values obtained in some other studies 8, 21. While the values reported by Mignon-Grasteau and Minvielle 11 were found to be similar to the mean egg weights measured in the white group, the values determined in the brown and gray groups were found to be higher. The values obtained in different groups in terms of shape index were found to be similar to the values reported by most researchers 7, 8, 19, 21, yet they were higher than the values reported by Şeker et al. 27 and lower than the values reported by Uluocak et al. 28. While the mean shape index values obtained from the brown group in the study were similar to the values reported by Nazlıgül et al. 18 and Özcan et al. 22, the mean values obtained from the gray and white groups were lower compared to the values reported by these researchers. In the present study, among the internal egg quality characteristics in quail groups of different plumage color lines, mean yolk weight values were higher compared to the values obtained in most studies 14, 18, 22, 27, 28 but similar to the findings of Kul and Şeker 8. The yolk weight obtained by Mignon- Grasteau and Minvielle 11 was similar to the values in the brown and white groups, while the value in the gray group was higher compared to the findings of the mentioned study. In these color lines eggs, albumen and yolk weight differences could indicate low or high cholesterol level, which is a subject for further research 9. While the mean albumen weight values in different groups in the study were higher when compared to the values stated by a number of researchers 11, 18, 22, 28, these values were similar to the findings of Kul and Şeker 8. The mean albumen weight values of the white group determined by Şeker et al. 27 were similar to the values obtained in the present study, but the mean values of the brown and gray groups were higher. Conclusions It is considered that differences among external and internal quality characteristics of eggs from quails of different plumage color lines result from a genetic variation. According to our opinion, egg width and shape index correlation differences and the egg width and length differences were due to body conformation differences in these plumage color lines. The basic reason was genetic variation among these lines. We think that more research on body conformation differences in different plumage color lines is necessary. We were also curious about the carcass weight of the different color lines for market consumption. The gray group external egg quality correlations were few in relation to other groups. The researchers view is Journal of Food, Agriculture & Environment, Vol.9 (2), April 2011 377

Table 4. Phenotypic correlations among certain internal quality characteristics of eggs obtained from quails with different plumage color lines. Plumage color groups Internal egg quality characteristics height width -0.005-0.127-0.040 length -0.048 0.051 0.188 weight 0.124 0.428** index 0.886*** 0.867*** 0.890*** 0.035 0.059-0.128 Haugh Unit 0.970*** 0.943*** 0.317* 0.967*** 0.564*** 0.341** 0.372** 0.295* 0.245 0.208 0.841*** 0.598*** -0.435** 0.300-0.125 0.431** 0.569*** 0.325* 0.207-0.374* -0.353* width 0.394** 0.378** -0.467*** -0.197-0.302* 0.201 0.261 0.458*** -0.060 0.203 0.191 0.578*** 0.699*** -0.440*** 0.094-0.226 0.288* 0.478*** 0.434** -0.125-0.052-0.070 0.513** -0.489** 0.529*** -0.133 0.222 0.353* 0.130 0.072-0.441** -0.496** length 0.377** -0.414** 0.033-0.067 0.307* 0.249 0.321* 0.028 0.097 0.036 0.650*** -0.226-0.152 0.018 0.198 0.672*** 0.637*** -0.383** 0.297* 0.242-0.152 0.574*** -0.107 0.337* 0.379* 0.617*** 0.174-0.524*** -0.553*** weight 0.147 0.254 0.135 0.442** 0.586*** 0.572*** -0.151-0.134-0.178-0.052 0.098 0.088 0.452*** 0.720*** 0.650*** -0.159-0.008-0.048-0.201 0.908*** 0.293-0.082-0.007 0.408** 0.159 0.200 index 0.088 0.899*** 0.097-0.123 0.006 0.181-0.121-0.095-0.116 0.949*** 0.394** 0.030 0.078 0.391** 0.176 0.162-0.046-0.115 0.004-0.231-0.161-0.858*** -0.951*** 0.126-0.163-0.246-0.626*** 0.074-0.930*** -0.972*** -0.065-0.400** -0.484*** -0.670*** 0.009-0.931*** -0.971*** Haugh 0.421** 0.067-0.098 0.485** 0.010 0.041 Unit 0.135-0.215-0.020 0.288* -0.143-0.132 0.443*** 0.127 0.162 0.357** 0.171 0.139 height 0.591*** 0.430** 0.890*** -0.017 0.042 0.292* 0.513*** 0.567*** 0.261 0.236 0.480*** 0.641*** 0.631*** 0.418** 0.421** diameter 0.443** 0.159-0.009-0.011 0.675*** -0.621*** 0.317* 0.302* 0.913*** -0.377** 0.577*** 0.548*** weight 0.264 0.331* 0.312* -0.166 0.729*** 0.703*** -0.132 0.745*** 0.726*** index -0.003 0.073-0.061-0.065-0.071-0.043 0.973*** 0.989*** 0.991*** ***: P<0.001 **: P<0.01 *: P<0.05. height 0.511** 0.298* diameter 0.155 0.041 weight 0.086 0.266 index 0.542*** 0.200-0.071-0.042 / -0.039-0.041 378 Journal of Food, Agriculture & Environment, Vol.9 (2), April 2011

that this group selection density is higher than that of the other groups. Another important finding is that the brown and the white plumage color lines do not have a strong egg width and shape index correlation. The authors think that this situation is related to selection density differences for these groups. Several studies have been conducted in this direction in recent years 12, 15, 16. The differences between the findings of several studies conducted on quails regarding the external and internal egg quality characteristics and the findings of the present study might have been caused by certain factors such as breed, maintenance, feeding and hen age. These differences may sometimes be a disadvantage in commercial quail and egg production, because even if production is carried out under the same management conditions, changes in economic profitability can be observed as the result of breeding flocks with different plumage colors. It can be suggested that benefit can be obtained from quails of different plumage color lines in producing commercial quail lines with high efficiency by utilizing the findings of this study. It is thought that quails of different plumage colour lines can be utilized in big quail production enterprises considering the fact that, as in chicken production, economic lives and the profitability of brown, gray and white commercial quail lines are different. Acknowledgements The authors would like to thank Çiftyıldız Quail Farm manager Mrs. Resmiye Çiftçi in Konya Province for providing the study materials. References 1 Altan, Ö., Oğuz, İ. and Akbaş, Y. 1998. Effects of selection for high body weight and age of hen on egg characteristics in Japanese quail (Coturnix coturnix japonica). Tr. J. Vet. Anim. Sci. 25:467-473. 2 Bardakçıoğlu, H. E., Türkyılmaz, M. K., Nazlıgül, A. and Önol, A. G. 2005. 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