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.

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A crossbreeding experiment was carried out in Egypt using a local breed (Baladi Red, BR) and New Zealand White (NZ) to estimate direct heterosis, maternal additive effects and direct sire effects on some growth and carcass traits in rabbits. Data of body weight (at 5, 6, 8, 10, 12 weeks) and daily gains (at intervals of 5-6, 6-8, 8-10, and 10-12 weeks) on 2153 weaned rabbits were collected. Carcass performance at 12 weeks of age (weight and percentages of carcass, giblets, head, fur, blood and viscera) on 213 male rabbits was evaluated. Estimates of coefficients of variation (CV) for most growth and carcass traits were high and ranged from 10.0 to 40.2%. Sire-breed was of considerable importance in the variation of growth traits and some carcass traits, while dam-breed contributed little. Sire-breed × dam-breed interaction affected (P<0.01 or P<0.001) most body weights and gains studied, while it contributed little to the variation of carcass traits. The purebred NZ resulted in rabbits with heavier weights and carcass and with lighter non-edible carcass (blood and viscera) compared to the BR. Heterosis percentages for most growth traits were significant and ranged from 2.5% to 5.0% for body weights and from 0.7% to 9.5% for daily gains. Insignificant positive direct heterosis was observed for most carcass traits. Crossbred rabbits from NZ sires with BR dams were superior to from the reciprocals. Maternal-breed effects on most weights and gains were insignificant, while sire-breed contrasts for some weights and gains proved significant. Postweaning growth and carcass performances of BR-mothered rabbits generally surpassed the NZ mothered, while NZ-sired rabbits were superior at later ages. High edible carcass was observed for BR-sired rabbits, while more non-edible carcass wastes (blood and viscera) for NZ-sired rabbits. Maternal-breed effects appeared to be less important than paternal-breed effects in influencing most weights, gains and carcass traits studied. ZUSAMMENFASSUNG: Heterosis, maternale und direkte Wirkungen bei Wachstums- und Schlachtkörpermerkmalen in Kaninchenkreuzungen Der Kreuzungsversuch wurde mit lokalen ägyptischen Rassen (BR) und Neuseeland Weißen (NZ) zur Schätzung direkter Heterosis, maternaler additiver Wirkungen, direkter Vater-Wirkung auf einige Wachstums- und Schlachtkörpermerkmale von Kaninchen durchgeführt. Angaben über Körpergewicht (5, 6, 8, 10, 12 Wochen) und Zuwachs (Intervalle 5 bis 6, 6 bis 8, 8 bis 10, 10 bis 12 Wochen) wurden von 2153 abgesetzten Kaninchen gewonnen. Die Schlachtkörperleistungen bei 12 Wochen Alter (Gewicht und Anteil von Schlachtkörper, Kopf, Pelz, Blut und Innereien) stammen von 213 männlichen Kaninchen. Schätzungen der Variationskoeffizenten (CV) für meiste Wachstums- und Schlachtkörpermerkmale waren hoch und bewegten sich zwischen 10 und 40,2%. Vaterrasse hatte erheblichen Einfluß auf Unterschiede in Wachstumsrate und einige Schlachtkörpermerkmale, während die Mutterrasse weniger beigetragen hat. Interaktion zwischen beiden beeinflußte die meisten Körpergew...

IntroductionThere is an increase in problems of the reproductive system in human males. This could be due to lifestyle factors, and chemical exposure in the work environment. Occupational activities involve constant exposure to toxic agents and may have a detrimental effect on human reproduction. This study aimed at assessing the semen quality among exposed workers to lead and cadmium.MethodsAccording to the inclusion criteria (at least 2 years of work exposure, age 20–45, non-smokers) 21 male workers (exposed group) in a welding unit at a shipbuilding facility in Ismailia Egypt and 42 office workers (control group) with the same criteria were compared. Personal, medical, reproductive and occupational histories were taken. Blood lead and cadmium concentrations were determined by atomic absorption spectrophotometer with Zeeman background correction (Perkin Elmer). Analysis of semen samples was performed in accordance with World Health Organisation criteria. P-value less than 0.05 were considered statistically significant in data analysis.ResultsThe blood level of lead and cadmium for the welding workers was 45.75±9.78 µg/dl and 1.68±1.60, respectively, which was significantly higher than the control group 12.65±3.78 and 0.15±0.22 (p<0.001). Sperm counts of welding workers were 31.12±22.97 millions/ml lower than those of the control group were 50.80±39.56 millions/ml (p=0.016) and also sperm motility was decreased in exposed workers compared to controls (p=0.003). The sperm motility showed a negative correlation with blood lead content in workers. Blood concentration correlated with the number of years of exposure to welding.ConclusionThis study shows that exposure to lead and cadmium may affect semen profile in male welding workers. Further studies are need to control for other potential confounding factors, and environmental assessment should be done to asses exposure pathways and concentration.