An analysis was carried out to evaluate the results of the selection program of a new synthetic maternal line of Egyptian APRI rabbits and the Spanish V line. The selection criterion was litter weaning weight in both lines based on Best Linear Unbiased Prediction (BLUP) estimations under a repeatability animal model. The studied traits were: litter birth weight, litter weaning weight (at 28 d) and pre-weaning litter gain. Heritability estimates were generally low (0.09 to 0.11) and comparable in both lines. Low to moderate estimates of repeatability were observed for all studied traits (0.15 to 0.31). Estimates of genetic correlations were high (0.77 to 0.97), while permanent environmental effects correlations were mostly lower than genetic correlations (0.47 to 0.87). The genetic trends were also estimated using mixed model methodology and were signifi cant and comparable (34.2 and 32.5 g) for the selected trait (litter weaning weight) in APRI and V lines, respectively. Furthermore, correlated genetic trends were signifi cant ( P<0.05) for other litter weight traits. These results indicate that the current selection program has been effective in achieving genetic improvement in litter weight traits.

This study was aimed to evaluate the genetic diversity of Egyptian native chickens by using mtDNA sequence polymorphism. A 546-bp fragment of the mtDNA D-loop region was sequenced for a total of 36 Egyptian native chickens with 14 reference sequences from DNA databank. Of the Egyptian chickens 5 haplotypes were identified. Haplotype diversity and nucleotide diversity of the Egyptian native chickens were 0.5635±0.0845 and 0.00123± 0.00108, respectively. The Egyptian native chickens were distributed within one clade, which were closed to the haplotypes from Indian subcontinent and Southeast Asia. Most of Egyptian native chickens were classified into the haplotype E1, which contains 63.9% of individuals followed by E4 (16.6%), E5 (11.1%), E2 (5.5%) and E3 (2.7%), respectively. These findings indicate that the maternal lineages was involved in the origin of domestic chicken in Egypt may have roots in Indian subcontinent and other Southeast Asia. The genetic information from this study will probably pave the way to further studies for evaluation, preservation and improvement of Egyptian native chickens as genetic resources in the future.

SummaryLive body weight, shank length, keel length and carcass dissection data taken at 6 weeks of age were available on 103 quails from 33 sires. In a principal factor analysis, the first varimax rotated factor explaining 46.1% of the total Variation, revealed that body weight had negative loading and all bone percentages positive. The implied contrast was confirmed by the finding that body weight (h 2 = 0.61) was genetically correlated negatively with weight of total bone relative to body weight (-0.23) and to carcass weight (-0.58). Noticeably, shank length (SL) had large positive genetic correlation with body weight (0.90) and practically independent relationship with body bone percentage (-0.04). Selection indexes for meat production capacity were construeted. The breeding goal was defined as body weight (BW) and body bone percentage (BBP). The descending order ofthe unrestricted indexes with respect to the correlation between the index and genetic worth was: the füll index utilising body weight, shank length and keel length (0.95), indexes based on body weight and one length measurement (0.86), body weight alone (0.78). The accuracy was reduced by 17-35% upon restraining changes in BBP to zero. This study indicated that an index of considerable accuracy and remarkable usefulness would be I 3 = 4.56 BW + 244.87 SL. Use of this index should result in developing birds with higher body weight and more advantageous carcass attributes than selecting for body weight alone (L) or on the restricted füll index (II(BBP)). Such three indexes were most efficient in limiting reduction in BBP.

Abstract. Estimates of phenotypic and genetic parameters for live Performance and detaiied dissection traits of body components and carcass tissues in Pekin ducks were calculated and used to construct selection indexes. The expected reduction in potential gain in live weight, dressing percentage and carcass characteristics resulting from restricting change in subcutaneous fat level to zero were assessed. The aggregate genotype measurements were weight at slaughter, dressing percentage and percent subcutaneous fat. The index measurements were weight at hatching, weight at slaughter, weight gain, breast width, breast length and breast circumference. The restricted indexes as compared with the unrestricted would lead to minimum reduction in potential gain of 29.4% in total net merit, 96.4% in weight at slaughter, 49.0% in dressing percentage, 74.0% in dissected side weight and 75.0% in muscle to bone ratio. The potential reduction in percent abdominal fat and percent bone in side was decreased by at least 38.5% and 80.2%, respectively. Absolute genetic response results showed that selecting for breast width alone (rTI = 0.79) would be recommended for birds with substandard levels of SCF, whereas use of the restricted index containing weight at hatching and breast width (rTI = 0.54) would be advised for individuals with Standard fatness.

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