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One thousand two hundred 1-day-old Lohmann LSL white and Lohmann Brown layer chickens were fed diets supplemented with either an antibiotic growth promoter (AGP) or an herbal essential oil mixture (EOM) till 58 wk of age to reveal the long-term effects of those additives on growth, performance and wholesome egg quality parameters. The study was arranged in a 2¥3 factorial design with two layer strains and three feed additive regimens. Thus, the layer birds of both strains were randomly assigned to the three dietary treatments, i.e., standard basal diet (control), control with AGP (specifically, avilamycin, 10 mg/kg diet) and control with EOM (24 mg/kg diet). The data regarding egg production were recorded between 22 to 58 weeks of age. Neither the dietary treatments nor the bird strain influenced the body weight and mortality of the birds in both the growing and laying period. AGP or EOM supplementation to the laying hen diet significantly increased the egg production rate and egg weight as compared to the control diet alone, but egg mass output, feed consumption, and feed conversion ratio were not affected by the dietary treatments. Neither dietary treatment created any statistically significantly differences in egg quality parameters. The research findings have confirmed the beneficial effects of supplementation with feed-grade EOM on the laying rate and egg weight of both white and brown layers.Indeed, EOM, being a novel feed additive natural origin, proved to be as efficacious as AGP in promoting egg yield.

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Temperate maize growing regions are increasingly prone to drought stress which is emerging as a primary constraint to maize productivity. Introgression of tropical sources of drought tolerance into temperate maize breeding may contribute to improving the drought tolerance of the relatively narrow temperate germplasm base that is currently in use. In the present study, seven tropical drought tolerant inbred lines and two welladapted commercial temperate inbred lines were crossed in a half-diallel design. The 9 parents, 36 diallel hybrids and 2 commercial checks were tested in well-watered and managed water stressed conditions in Antalya, Turkey in 2013 and 2014. Significant differences were detected between genotypes for number of days to anthesis, anthesis-silking interval, plant height, thousand kernel weight, number of ears per plant, number of kernels per ear and grain yield. Tropical inbreds G1 and G5 were comparable to the adapted temperate commercial inbreds in terms of general combining ability. Specific combining ability analysis revealed that tropical x temperate hybrids had higher values compared to tropical x tropical hybrids. Yield potential of hybrid G5 x G9 in particular, a promising tropical x temperate hybrid, was significantly higher under both well watered and drought conditions. Our results suggest that tropical drought tolerant germplasm is likely to have high utility in temperate maize breeding programs.

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