Phenotypic and Genotypic Characterization of Sudanese Indigenous Bare Neck Chicken

Abstract

The indigenous chickens are known of low productivity and adaptability to their local environment which made them to be resistant to some extend to some diseases prevalent in their localities more than exotic breeds. In this study two experiments were conducted. The trial was concerning phenotypic trial of indigenous Bare neck chicken. The second experiment was handling three genes\in order to show polymorphism in the three genes GH, PIT1 and PRLR. In the first trial phonetic performance of the Sudanese indigenous bare neck was determined which include body weight, body weight gain, feed consumption, feed conversion ratio, age at first egg, egg quality characteristics, inedible and edible carcass cuts and the mean values of chemical analysis and sensory evaluation percentages are as below: The mean weights of body weight observed were 27.37±2.12g, 131.89±11.25, 339.24±72.42, 525.43±97.17g and 739.33±147.13g during rearing period of 0, 4, 8, 12, 16 weeks of age. The initial and final weights of males and at (0, 16) weeks were (28.79, 816.43g) for males and (26.96g, 699.63g) for females. The body weight gains were 104.24g, 207.36g, 187.18g, and 213.09g at 4, 8, 12 and 16 weeks of age. Feed consumption was 401g, 702, 920g and 932.06g at 4, 8, 12 and 16 weeks of age. Feed conversion ratios were 3.84, 3.39, 4, 98 and 5.47 at 4, 8, 12 and 16 weeks of age. The age at first egg was 148.44 days with mean egg weight and body weight of 33.50 g and 1006.7g respectively. The egg quality characteristics showed mean values of external and internal egg quality. The external egg quality of egg weight, egg length, egg diameter, shell weight, shell thickness and egg shape index mean vales were 31.43±0.85g, 46.11±0.42mm, 34.93±0.40mm, 4.30±0.08g, 0.38±0.04 mm and 0.75.87+1.17. The internal quality characteristics of albumen weight, albumen height, yolk weight, yolk height, yolk diameter, yolk index and Haugh unit mean values were 18.01±0.65g, 4.31±0.39 mm, 9.05±0.28g, 13.54±0.29mm, 32.55±0.33mm, 0.42±0.01 and 75.2012.34. The measurement of carcass cuts consists of inedible and edible carcass cuts weights. The inedible carcass cuts weights were composed of blood weight, feather weight, head weight, neck weights, legs weights, intestine weights, abdominal fat weights, wings weights, shank weights, shank length and back weights. The mean weights of these traits at 8, 12 and 16 weeks of age were (15.00±6.55g, 26.56±11.06g and 30.00±9.78g) blood weights, (15.65±8.84g, 17.81±5.76g and 37.19±19.58g) feather weights, (19.87±3.38g, 23.38±2.80g and 29.06±12.44g) head weights, (13.67±3.96g„ 17.63±3.20g and 29.69±5.87g) neck weights, (23.33±6.70g, 25.13±4.38g and 27.62±6.70g) legs weights, (27.47±4.9g, 37.94±7.75g and 47.94±7.51 g) intestine weights, (0, 2.50±1.67 and 3.19±2.12g) abdominal fat weights, (24.93±4.13g, 42.81±9.00g and 57.62±12.76g) wings weights, (5.87±2.17g, 6.13±2.42g and 6.8711.93g) shank weight, (4.53+0.74 cm, 5.31+0.48 cm and 5.94±0.77cm ) shank length and (41.33±10.07 g, 87.13±24.29 g and 138.76±26.30 g) back weights. The edible carcass cuts weights of giblets, (gizzard weights, heart weights and liver weights) and commercial carcass cuts weights (breast, thigh and drumstick) mean at 8, 12 and 16 weeks of age were (12.73±2.84g, 15.88±2.06g and 17.25±3.62g) gizzard weights, (3.00±1.36g, 3.44±0.63g and 4.50±1.71g) heart weights and (14.60±3.80g, 20.81±4.02g and 21.94±6.31g) liver weights. The commercial carcass cuts weights of breast, thigh and drumstick at the same period above were (58.27+39.41 g, 71.25±14.14g and 115.38±30.74g) breast weight, (40.93±25.06g, 48.00±11.08g and 73.88±16.18g) thigh weight and (37.33±22.50g, 39.88±6.98g and 60.63±12.94g) drumstick weights. The meat and bone mean weights of breast, thigh and drumstick at the same period were (45.07+36.32g, 56.50±14.76 and 95.87±25.44g) breast meat weights and corresponding breast bone weights were (12.27±4.33g, 15.75±5.36g and 19.38±8.66g), (31.53±21.68g, 37.88±9.65g and 59.25±14.25g) thigh meat weights and (9.33±8.06g, 10.00±2.63g and 14.63±4.66g) corresponding thigh bone weights and (25.87±18.49g, 29.63±6.21g and 46.88±11.31g) drumstick meat weights and (9.0014.52g, 10.50±3.46g and 13.87±4.76g).corresponding drumstick bone. The chemical analysis percentages of moisture, protein, fat and ash were 77.06±0.70% 19.60±0.59% 2.07±0.01 % and 1.04±0.01% respectively. The sensory evaluation traits of breast, thigh and drumstick attributes as judged by the panelists showed the scores on attributes of tenderness of breast, thigh and drumstick scored 35.52%, 33.73% and 30.75% respectively. The flavor of breast, drumstick and thigh scored 36.39%, 32.95% and 30.66%. The colour of breast, thigh and drumstick scored 34.66%, 34.66% and 30.68%. The juiciness of breast, thigh and drumstick scored 37.08%, 34.19% and 28.75% respectively. The second experiment was based on polymorphism of three genes, namely PIT1; GH and PRLR which were genotyped by using PCR-RFLPs technology in six Sudanese indigenous chicken lines and they are: Bare neck (1; 2); Large Baladi (1; 2); Frizzle and Betwil. For each line, twenty blood samples were collected from wing vein; DNA was extracted, PCRs were performed using specific primers for the genes understudy, the PCR products were characterized after cutting the products with previously reported restriction enzymes. The results showed the absence of polymorphism for the PRLR gene which shows only one allele or genotype (B; BB) and the other two genes were polymorphic. The GH gene showed two alleles (A; B) with three genotypes (AA; AB; BB), while the PIT1 gene showed also two alleles (A; B) with only two genotypes (AA; AB), frequencies of alleles and genotypes were varying according to the line. In conclusion the GH and P1T1 genes can be used in genetic improvement of Sudanese chickens while PRLR gene cannot be used due to the lack of polymorphism in it.