University of Khartoum

Genetic and Phenotypic Aspects of Body Weights in Local Large Beladi Chicken Raised Under Two Different Dietary Constituents

Genetic and Phenotypic Aspects of Body Weights in Local Large Beladi Chicken Raised Under Two Different Dietary Constituents

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Title: Genetic and Phenotypic Aspects of Body Weights in Local Large Beladi Chicken Raised Under Two Different Dietary Constituents
Author: Abd Elrahman,Elsheikh Mohamed Ahmed
Abstract: The foundation stock was primarily established by purchasing 50 cockerels and 160 pullets of the indigenous fowl from the Blue Nile area (Sinar state). This work was conducted to compare the genetic and phenotypic parameters estimates for body weights of large Beladi chicken under two different feeding regimes and proposing outlines of a strategy for improving body weights at different ages. Each cockerel was randomly assigned to mate with three pullets in a rotational pattern. Eggs for incubation purpose were collected from the individual breeding pens three times a day and recorded on daily basis. Eggs were weighed, graded and pedigreed and then incubated to obtain 13 consecutive hatches at weekly intervals. The total number of birds used in the experiment was 1718. According to the experimental protocol, which based on feeding regime, chicks were divided into two groups (A) and (B). Birds in group (A) were fed on broiler-formulated rations, whereas birds in group (B) were fed on layer-formulated rations. For group (A) individual body weights were taken at biweekly interval up to 12 weeks. However, for group (B) individual body weights were taken at monthly interval up to 3 month. The overall average body weights for birds at hatch, 4, 8 and 12 weeks in group (A), were 26.78±2.91, 147.16±30.87, 393.51±64.12 and 800.93±155.97g, respectively, whereas, the corresponding weights in group (B), were 29.31±2.66, 170.80±49.27, 353.43±102.70 and 512.75±116.11. Mean body weights of birds in group (B) were significantly (P < 0.05) higher than those in group (A) at hatch and 4 weeks of age, however, the reverse was true for body weights at 8 and 12 weeks of age. Growth pattern revealed an increasing trend with advanced ages. On the other hand, the monthly weight gain showed marked decline at 8 weeks of age for birds in group (B). Comparing growth of birds in A and B groups revealed that, increasing dietary protein and metabolizable energy (ME), resulted in increase body weights at 8 and 12 weeks of age by 11.3 and 56.2 percents, respectively. In group (A), the mean body weights of males were significantly (P < 0.05) higher than those of females at 4, 6, 8 and 12 weeks of age. This may express the presence of heterogeneity between sexes at these ages. Sire and dam effects on body weights were found to be significant at various ages. Hatch had significant effect (P < 0.01) on body weight at all ages. Heritability estimates for body weights at different ages from sire, dam and sire plus dam components of variance were obtained for both groups. The estimates in group (A) and (B) ranged from low (0.02) to high (0.97) and low (0.06) to moderate (0.25), respectively. In group (A), heritability estimates from dam component were higher than those from sire component, whereas the reverse was true for the estimates in group (B). Heritability estimates for body weights in group (A) were slightly higher than those in group (B). This may reveal the tendency for increasing heritability magnitudes with improved levels of dietary protein and metabolizable energy (ME). For both groups (A) and (B), the genetic and phenotypic correlation estimates ranged from low (0.16) to high (0.97) and followed similar trends. However, the magnitudes were relatively higher in group (A) than those in group (B). The environmental correlation estimates were also positive, ranged from low (0.08) to high (0.99), and followed similar trend. Based on sire component of variance, the highest heritability estimate in group (A) was at 4 weeks of age, whereas the corresponding estimate in group (B) was at 8th week. Generally, it may be concluded that mass or individual selection for body weight is better to be conducted at 4th week, when birds are fed on diet with high protein and metabolizable energy (Broiler ration) and at 8th week, when birds are fed on diet with low protein and metabolizable energy (Layer ration).
URI: http://khartoumspace.uofk.edu/handle/123456789/8401
Date: 2008


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