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Five years crossbreeding experiment was preformed involving two synthetic rabbit lines of APRI (A) and Moshtohor (M) where bucks of APRI line and does of Moshtohor line were used to produce F1 crossbreds (½A½M), followed by inter-se mating to obtain F2 crossbreds (½A½M)². PCR-RFLP technique was used to detect the SNP genotyping of MSTN gene in APRI and Moshtohor lines and their progenies of F1 and F2 crossbreds and to detect the molecular associations between SNP genotypes of MSTN candidate gene and growth traits using FspBI restriction enzyme. Two genotypes of MSTN gene were detected (TT and TA) in each separate genetic group. The variance components estimated by Gibbs Sampling were used to solve the mixed model equations using the PEST software, getting the solutions for genetic groups effects along with the solutions for other fixed effects. Then, the generalized least-square means (GLM) for the two genotypes of the MSTN gene were estimated using the PEST software. The GLM obtained for body weights at 4, 6, 8, 10 and 12 weeks of age in both crosses of ½A½M and (½A½M)² were higher than those of their parental lines of APRI and Moshtohor. But, APRI-line rabbits were nearly similar in body weights to Moshtohor line rabbits at 8, 10 and 12 weeks of age. The effective numbers of alleles (Ne) were 1.26, 1.08, 1.11 and 1.37 in APRI line, Moshtohor line, ½A½M and (½A½M)² crosses, respectively. High degrees of similarity were detected between the numbers of expected and observed genotypes in all genetic groups and therefore these genetic groups were in Hardy-Weinberg equilibrium (HWE) for MSTN gene. The values of polymorphic information content (PIC) were low and ranged from 0.073 in Moshtohor line to 0.235 in (½A½M)² cross. The genotypic frequencies of TT genotype of MSTN gene were high in all genetic groups (0.68 to 0.92). The allelic frequency recorded for T allele was much higher than for A allele. The heterozygosis for MSTN gene in all genetic groups were low or moderate, ranging from 0.079 to 0.323 for the observed heterozygosity (HO) and 0.076 to 0.271 for the expected heterozygosity (He). The reductions in heterozygosity due to inbreeding (FIS) in all genetic groups were low. In different genetic groups, both TT and TA genotypes of MSTN gene were found to be significantly associated with most body weights and gains at different ages. In APRI line and (½A½M)² cross, TT genotype was positively associated with an increase in most body weights. In Moshtohor and ½A½M cross, TA genotype was positively associated with heavy body weights. High means for TT and TA genotypes of MSTN gene in ½A½M and (½A½M)² crosses were recorded and showing strong positive associations of both TT and TA genotypes of MSTN gene with most body weights and gains. [ABSTRACT FROM AUTHOR]

Copyright of Egyptian Poultry Science Journal is the property of Egyptian Poultry Science Association and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Four synthetic strains of chickens, including Matrouh (MT), Mandarah (MN), Silver Montazah (SM) and Inshas (IN), were used in a crossbreeding experiment for four years to estimate direct additive genetic effects ( GI ), maternal effects ( GM ), direct heterosis ( HI ) and maternal heterosis ( HM ) for age and weight of hen at the first egg, weight of the first egg, egg number and mass for the first 10 eggs, egg number and mass during 90 and 120 days of egg production, egg number and mass for two days per week of production, egg number and mass for one week per month of production and clutch sizes and pause durations during 90 and 120 days of egg production. The egg production traits were recorded for a total of 747 sexually mature hens belonging to the different genetic groups. A total of 34 sires and 230 dams from MT chickens, 32 sires and 199 dams from MN chickens were used to produce 2894 chicks of the parental generation of MN and MT. In crossbreeding generations, two-way crossbreds (653 chicks of ½MN½MT and ½MT½MN) and three-way crossbreds (809 chicks of ½IN¼MN¼MT and ½SM¼MT¼MN) were produced. The estimates of on all egg traits studied were significantly in favour of MN strain (P≤0.01). Also, the estimates of were significantly in favour of MN dams for age at first egg, most egg production traits and clutch sizes, while the estimates for pause durations were in favor of MT dams. Estimates of were significant with favorable heterotic rates ranging from 3.8 to 28.5 % for maturity of hen at the first egg, 19.7 to 29.3 % for egg production and 3.2 to 36.1 % for partial egg recording (P≤0.05 or P≤0.01). The percentages of were favorably positive for all clutch sizes (ranging from 13.1 to 57.4 %; P≤0.01), while they were favorably negative for all pause durations (ranging from -17.3 to -44.2 %; P≤0.01). The percentages of were favorable with heterotic rate of -2.6 % for age at the first egg (P≤0.05) and 7.8 to 8.2 % for egg production (P≤0.01). The heterotic maternity was favorably positive and ranging from 3.2 to 10.5 % for four traits of partial egg recording (P≤0.05) and 4.6 to 15.5 % for most clutch sizes (P≤0.05 or P≤0.01), while they were favorably negative for all pause durations (-5.0 to -31.8 %; P≤ 0.05 or ≤ 0.01). [ABSTRACT FROM AUTHOR]

Copyright of Annals of Agricultural Science Moshtohor is the property of Egyptian National Agricultural Library (ENAL) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)