| For nearly years, a quality of people to the chicken meat quality and eggs quality put forward higher request, no longer blandly pursue fresh taste, more requirement of the meat and eggs is in line with the standard of green food. This experiment was conducted to investigate the Laiwu Black Chicken slaughter performance and regular meat quality and the chemical composition of the breast and the leg meat, inosinic acid, amino acids, fatty acids and reproduction performance and eggs quality of Laiwu Black Chicken, to compare analysis,so as to reveal the overall features of Laiwu Black Chicken muscle and egg quality,.and on this basis, we will purify feather color to establish the core Laiwu Black Chicken group.So it can provide important data for genetic improvement and the development and utilization of Laiwu Black Chicken.The results were as follows:1. Cock had greater weight than hen every week in growing period. 180 days cock weight1834.72 grams, and hen weight 1617.04 grams.2. The results in180-day-old chicken indicated that the percentage of dressed weight,percentage of eviscerated yield with giblet,percentage of eviscerated yield in male and female were 88.16%and 88.87%, 81.5%and 78.77%, 68.36% and 65.16%, with good meat production performance. In the matter of physical and chemical properties of muscle, the pH value of breast muscle and leg muscle were between 5.74 and5.79, Eikelenboom(15) defines PSE and DFD muscle according to pH value after slaughter,in this experiment, Laiwu Black Chicken is PSE. Cock’s muscle shearing force was greater than hen muscle shearing force, the hens muscle tenderness was better,and leg muscle shearing force was greater than breast muscle, the breast muscle tenderness was better,the differences between the cock and hen’s breast muscle and leg muscle were not significantly( P >0.05).In general, the high quality chicken have smaller shear force(0.5 ~ 0.7 kg), and ordinary chicken is above 1kg more, but Laiwu Black Chicken shearing force is bigger, tenderness is ordinary.Crude protein content of breast and leg in cock is 21.07% and 18.95%,respectively,the hen is 21.21% and 21.63%.Crude fat content is 2.16%~2.76%, Dik considered that the best scope is 2.5%~3%, so Laiwu black chicken has a good delicious palatability. Ash content of breast and leg in cock is 7.17%and 6.29%, respectively, the hen is 7.12% and 5.43%. Ash and Crude protein and Crude fat in gender and part shows no significant difference(P > 0.05).Variety of fatty acids in chest and leg muscle, and oleic acid content is the highest, palmitic acid, linoleic acid, stearic acid content is more also. In Laiwu Black Chicken, chest SFA, MUFA and PUFA is greater than the leg muscles, it is said that chest muscle fatty acids content is more than leg muscle. In Laiwu Black Chicken DHA(c22:6n3), chest muscle is higher than leg muscle in the fatty acid,but no significant difference(P > 0.05).3. The average egg weight of Laiwu Black Chicken in 360 day was 50.64 g, index of egg shape was 1.33, eggshell intensity was 4.15kg/cm2, eggshell thickness was 0.30 mm, Haugh unit was 51.43, the proportion of egg yolk was 35.85%. The hangh unit and the protein have the positive correlation. The fertility rate of Laiwu Black Chicken was 95%, the hatching rate was 92%.4. MC1 R 、TYR gene control chicken fenther color,Judging in MC1 R and TYR genetype of Laiwu Black Chicken, we set up the core group, F1 generation of feather color purification results ideal significantly through strict Artificial Insemination and Pedigree Hatch, purification rate was 98.9%, Miscellaneous feather ratio is 1.1%, by adjusting the next generation of insemination and eliminating some chickens, there will be a higher proportion of black feathers after.In the process of Laiwu Black Chicken feather color purity, MC1 R gene Polymorphism information content is 0.254,it is moderate polymorphism(0.25<PIC<0.5),χ2 analysis showed that MC1 R genotype rate deviated significantly Hardy-Weinberg equilibrium state(P<0.0001).TYR gene Heterozygosity is 0.064,the number is small,Degree of genetic variation within population is small,Polymorphism information content is 0.062,it is lower polymorphism(PIC<0.25, χ2analysis showed that TYR genotype rate conforms Hardy-Weinberg equilibrium state(P>0.0001), theoretically, the TYR gene is negligible.To sum up, Laiwu Black Chicken had rich genetic diversity and high heterozygosity, the polymorphism was better, the genetic variation was greater.In a word,the groups had larger space in further purification. The growth and development performance, meat productionperformance, meat quality, reproductive performance and egg quality of Laiwu Black Chicken have outstanding performance, indicating that Laiwu Black Chicken is worth promoting, it is a indigenous poultry stock. Laiwu Black Chicken purification result is ideal, this will provides the theoretical foundation for further breeding of Laiwu Black Chicken. |
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