84 research outputs found
Effect of a dietary essential oil mixture on performance of laying hens in the summer season
The experiment was conducted to evaluate the effects of dietary supplements of either an essential oil mixture (EOM) or a mannan oligosaccharide (MOS) as alternatives to an antibiotic feed additive (avilamycin) for layers kept under hot summer conditions. Four hundred and eighty 54-week old Nick-Brown hens were assigned to four dietary treatments. Each treatment consisted of four replications of 10 cages (three hens per cage). The treatment groups were: 1) Control: Basal diet without additive; 2) Basal diet plus antibiotic (10 mg avilamycin/kg feed); 3) Basal diet plus 1 g MOS/kg feed; 4) Basal diet plus 24 mg EOM/kg feed. Performance of laying hens was affected by dietary treatments. Dietary supplementation of EOM and MOS significantly increased egg production compared with control and antibiotic groups. There were no significant differences in feed consumption between treatments. The EOM significantly improved feed conversion ratio above that of the control group. Egg weights were significantly different between treatments. Laying hens consuming MOS produced significantly lower egg weights than the other groups, while egg weights in the EOM, antibiotic and control groups did not differ significantly. Cracked-broken egg rate was decreased by dietary addition of EOM, MOS and antibiotic compared with the control. Number of deaths among hens was significantly affected by dietary treatments with the number of deaths in the MOS treatment being significantly lower than in the other treatments. The performance of laying hens during the summer season could be maintained with inclusions of EOM and MOS in the diet. Keywords: Essential oils, mannan oligosaccharide, antibiotic, egg production, laying hen, summer seasonSouth African Journal of Animal Science Vol. 36 (4) 2006: pp. 215-22
Reconciling the stratigraphy and depositional history of the Lycian orogen-top basins, SW Anatolia
Terrestrial fossil records from the SWAnatolian basins are crucial both for regional correlations and palaeoenvironmental reconstructions.
By reassessing biostratigraphic constraints and incorporating new fossil data, we calibrated and reconstructed the late Neogene
andQuaternary palaeoenvironments within a regional palaeogeographical framework. The culmination of the Taurides inSWAnatolia
was followed by a regional crustal extension from the late Tortonian onwards that created a broad array of NE-trending orogen-top
basins with synchronic associations of alluvial fan, fluvial and lacustrine deposits. The terrestrial basins are superimposed on the upper
Burdigalian marine units with a c. 7 myr of hiatus that corresponds to a shift from regional shortening to extension. The initial infill of
these basins is documented by a transition from marginal alluvial fans and axial fluvial systems into central shallow-perennial lakes
coinciding with a climatic shift from warm/humid to arid conditions. The basal alluvial fan deposits abound in fossil macro-mammals
of an early Turolian (MN11–12; late Tortonian) age. The Pliocene epoch in the region was punctuated by subhumid/humid conditions
resulting in a rise of local base levels and expansion of lakes as evidenced by marsh-swamp deposits containing diverse fossilmammal
assemblages indicating late Ruscinian (lateMN15; late Zanclean) ageWe are grateful for the support of the international
bilateral project between The Scientific and Technological Research
Council of Turkey (TUBITAK) and The Russian Scientific Foundation
(RFBR) with grant a number of 111Y192. M.C.A. is grateful to the
Turkish Academy of Sciences (TUBA) for a GEBIP (Young Scientist
Award) grant. T.K. and S.M. are grateful to the Ege University
Scientific Research Center for the TTM/002/2016 and TTM/001/2016
projects. M.C.A., H.A., S.M. and M.B. have obtained Martin and
Temmick Fellowships at Naturalis Biodiversity Center (Leiden). F.A.D.
is supported by a Mehmet Akif Ersoy University Scientific Research
Grant. T.A.N. is supported by an Alexander-von-Humboldt
Scholarship. L.H.O. received support from TUBITAK under the 2221
program for visiting scientists
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Quaternary time scales for the Pontocaspian domain: interbasinal connectivity and faunal evolution
The Pontocaspian (Black Sea - Caspian Sea) region has a very dynamic history of basin development and biotic evolution. The region is the remnant of a once vast Paratethys Sea. It contains some of the best Eurasian geological records of tectonic, climatic and paleoenvironmental change. The Pliocene-Quaternary co-evolution of the Black Sea-Caspian Sea is dominated by major changes in water (lake and sea) levels resulting in a pulsating system of connected and isolated basins. Understanding the history of the region, including the drivers of lake level and faunal evolution, is hampered by indistinct stratigraphic nomenclature and contradicting time constraints for regional sedimentary successions. In this paper we review and update the late Pliocene to Quaternary stratigraphic framework of the Pontocaspian domain, focusing on the Black Sea Basin, Caspian Basin, Marmara Sea and the terrestrial environments surrounding these large, mostly endorheic lake-sea systems
Origin and evolution of the thermal waters from the Pamukkale Geothermal Field (Denizli Basin, SW Anatolia, Turkey): Insights from hydrogeochemistry and geothermometry
The Pamukkale Geothermal Field (PGF) of the Denizli Basin (SW Turkey) is one of the most distinguished active geothermal fields known in the World. The thermal waters from the PGF are subdivided into two groups (Group 1A: Ca-HCO 3 and Group 1B: Ca-SO 4 types). The cold waters are also classified into two groups (Group 2A: Ca-HCO 3 and Group 2B: Mg-HCO 3 types). The hydrogeochemical properties of the PGF thermal waters suggest interactions with the basal metamorphic rocks of the Menderes Massif, tectonically overriding by the carbonate rocks of the Lycian Nappes and sedimentary rocks of the Neogene formations. The bedrock units are stratigraphically overlain by the Neogene sedimentary units of the Denizli Group. The thermal springs of the PGF are affected by several hydrothermal processes including mixing, water-rock interaction and input of mantle volatiles. The thermal water plots of the PGF deviate from the full equilibrium line indicating a low water maturity and/or mixing processes. Mixing models and Na-K-Mg ternary diagram suggest mixing between meteoric and thermal waters during the uprising of the deep-originated fluids. The water-rock interaction leads saturation of calcite and induces travertine precipitation in the discharge area. Low tritium (<1 TU) values of the PGF thermal waters confirm a deep circulation. The δ 18 O (−9.23 to −8.32‰) and δD (−61.00 to −57.00‰) isotopic values of the PGF indicate that the meteoric waters serve as the source of the thermal waters. Based on the δ 18 O and δD data, the PGF thermal waters are produced from precipitation in the southern side of Yenice Horst with elevation of 850–880 m.a.s.l. The δ 13 C DIC values (+6.26 to +8.07‰) of the PGF thermal waters indicate that CO 2 in thermal waters is mainly of a metamorphic origin. In order to identify the reservoir temperature of the PGF, various geothermometric methods have been applied. Accordingly, theoretical reservoir temperature ranges from 60 to 125 °C. The total hydrothermal CO 2 flux in the PGF is calculated to be approximately 1.4 × 10 8 mol/year (excluding free CO 2 flux) as similar to those of other geothermal fields in the World (e.g., central-southern Italy). This study proposes a conceptual hydrogeological-hydrogeochemical-tectonic model for the PGF: the thermal waters are derived from the infiltration of rainwater through fractures and faults in high recharge areas to the deep hot reservoir. Heating produced by the high geothermal gradient is interpreted in relation with the regional crustal thinning. Thermal waters upwell along WNW-ESE-trending deep faults and fractures (the Pamukkale Fault System) that act as hydrothermal pathways favouring migration of a huge amount of CO 2 -rich gas from deep geothermal reservoir. The geochemical and isotopic data of the thermal waters and gas indicate that the degassing of both metamorphic CO 2 and mantle derived CO 2 occurs in the PGF. Helium isotope data indicate that mantle volatiles produce possibly an upwelling into asthenosphere and ascent along these tectonic discontinuities. In this context, the PGF is one of the best example of geothermal fields as an interaction of active magmatism in the actively extending crustal setting. © 2018 Elsevier B.V
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