Effect of Age and Sex on some Physical and Chemical characteristics of Quail carcasses

The purpose of this study was to evaluate the effects of age and sex on live local desert line quail, dressed carcass yields, and meat chemical composition in whole meat , A total number of 60 quails at 6 , 9 and 12weeks , each groups contains 20 birds ( 10 males and 10 females), and measurements are taken for the following traits : live body weight, carcass weight, dress percentage and percentage of each part of. The experiment performed according to 3 × 2 factorial experiment in randomized complete design with three replicates. Results: the results showed that there were highly significant differences between males and females in body weight, dress percentage, thigh percentage , wing percentage , gizzard percentage and cooking loss , although Results revealed that significant (P < 0.05 ) increases in live body weight, carcass weight , dressing percentage , percentages of thigh , wings , neck , liver ,heart, gizzard, chemical meat composition were observed in addition of water holding capacity (WHC), cooking loss were also increased as the birds get older.


MATERIALS AND METHODS
This experiment was conducted in the quail breeding house of Zharawa private Quail breeding project , A total of 60local desert line quails at ages 6 , 9 and 12 weeks . The birds were bred in cages under controlled environmental conditions and provided with food and fresh clean water was offered ad libitum . Each live bird was weighed and slaughtered to ensure complete bleeding. The feathers, neck, edible and inedible viscera (head, preen, gland, feet, lungs, gizzard and liver) were removed. Finally carcass was weighed to observe the carcass yield.

Analysis of carcass composition
Breast, thigh, back, Wing and neck parts of carcass were weighed separately to evaluate the carcass composition of quail bird.

Chemical analysis
Protein (Kjeldhal), fat (Ether extraction) and ash contents of quail meat were determined according to the methods described by Association of Official Analytical Chemists (AOAC, 2000). All data were analyzed by using the General Linear Models procedure (SAS, 1996) to study the effect of treatments and strains according to Factorial -CRD (4*2) experiment ( two way with interaction), significant differences among the means of the levels of each factor were determined by Duncan multiple range test . Table 1 The results show significant difference (P<0.05) in means of the Slaughter weight (g), at the age of 6, 9 and 12weeks, 172.50g, 169.83g and 193.50g respectively. Quails will attain the best slaughter weight (169.0g) at the age of 12 weeks under a good feeding management. According to Wilkkanowska et al.2011 quail carcass yield characteristics are affected by age, the body weight increases with age, older birds have higher carcass weight compared to young birds. The cold carcasses weight and dressing percentage at 6, 9 and 12 weeks were (100.33, 104.91 and 116.41 g), ( 58.44 , 61.93 and 60.91%) respectively.. This reveals that at week 12 is the best age at which greater carcass yield can be realized, cold carcass weight are higher in week 12 compared to the weights at weeks 6 and 9 Table 1 the main effect, sex, was significant (P<0.05) on quail live body weight and dressing percentages . Female quail birds had a higher mean value than the male counterpart (191.11g Vs 166.11g). These results concur with studies by Simeon , 2015 which reported that the Japanese quail is a sexually dimorphic bird with females having a larger body size than males unlike other poultry species. The quail birds showed differences in growth pattern between sexes, the males displayed slightly higher dressing percentages than the females (63.44% Vs. 58.89%) respectively. This difference could be associated with the aggressiveness of males over the females especially when reared together; the females are disadvantaged during feeding and watering. Musa et al , 2006 However, the growth pattern variation was different with the results by in which female quails produced higher carcass yields than male quails, the smaller body weight and decrease in live weight in male quails was associated with higher metabolic rates and hormonal change respectively. In Table ( 2 ) showed none significant differences in PH at the ages 6 , 9 and 12weeks and also between males and females . this due to glycogen is static all ages .Although revealed significant difference in water holding capacity and cooking loss at ages 6 , 9 and 12 weeks this due to increase protein percentage by ages lead to decrease free water according to Anadon , 2012 . As well as there are significant difference in cooking loss at ages 6 , 9 and 12 weeks this due to increase fat percentage lead to loss water during cooking Different letters in the same column indicate a statistical difference (P < 0.05). Different letters in the same column indicate a statistical difference (P < 0.05).

RESULTS AND DISSCUSION
In table ( 3). Showed no significant differences among treatments in some part of carcass percentage such as breast % , back % and heart %but there was significant differences (P<0.05) in liver % , wings % , neck % , thigh % and gizzard % at ages 6 , 9 and 12 weeks These results are in agreement with those of Maurice , 2006 who suggested the appropriate age to slaughter the quail bird is between 5 to 6 weeks of age. Other parameters such as liver % and gizzard % showed significant differences (P<0.05 in relation to slaughter weight while the Wings % and Thighs (%) had significant differences in relation to the cold carcass weight,(%) cold carcass , and also there were no significant differences between males and females in some parts of carcass percentage such as breast % , back % , liver % and heart % this agree with Walita et al , 2017 showed no significant between males and females in same traits however , the significant differences was found in thigh % , wings % ,neck % and gizzard% . In table ( 4). Showed significant differences in meat chemical composition at ages 6 , 9 and 12 weeks such as moisture % , protein % , fat % and ash % in whole meat, also there were significant difference in protein % between males and females . The meat of young quail showed higher protein and moisture contents and lower fat content than spent quail meat. Research on animal meat has indicated that an increase in age is accompanied by an increase in intramuscular fat (Lawrie, 1991). According Baker and Derfler, 1981 showed that decrease moisture as birds get order and increase dry matter. Different letters in the same column indicate a statistical difference (P < 0.05). Different letters in the same column indicate a statistical difference (P < 0.05).

CONCLUSIONS
Carcass yield of Japanese quail is affected by several factors such as age and sex Female quail birds registered higher carcass traits than the male counter parts. Female quail birds have higher slaughter weight as compared to the males. The study concludes that the optimal age to slaughter quail birds is around 12 weeks. Higher carcass yields as well as dressing percentages are realized at this age.