98 research outputs found
Effect of short-term pre-hatch heat shock of incubating eggs on subsequent
The aim of this study was to investigate the effect of thermal conditioning of broiler chickens during embryonic development on subsequent performance under standard rearing conditions. During incubation eggs from 32-, 45- and 56-week old Ross 308 broiler parent stock were subjected to a 2 h heat shock of 39 °C on days 14 and 15 of incubation. Eggs in the control were incubated throughout incubation at 37 °C. Chicks were feather sexed and equal numbers of each sex were placed in each pen per treatment, and reared for 42 days. Live weight, mortality and feed conversion ratio (FCR) were used as measures of performance. The final (six-week) live weights of broilers from young, mid and older parents for the treatment and control groups were 2113 ± 13.8 vs. 2159 ± 20.0, 2084 ± 29.2 vs. 2139 ± 20.0 and 2096 ± 17.6 vs. 2131 ± 24.3 g, respectively. The six-week live weight of the heat-treated group (2098 ± 12.0 g) was significantly lower than that of the control (2143 ± 12.2 g). The 1-6 week mortality figure was significantly lower in the heat-treated group of chickens from the young (83) and mid parent (77) groups compared to their controls (130 and 119), respectively. However, in the treatment group the incidence of mortality in broilers from the older parent group was significantly higher (105) than that of the control (79). The overall mortality without considering the parent age group was significantly lower in the treatment group (265) than in the control group (328). Mean FCR (g feed/g gain) of the chickens of the three parent groups was 1.79 ± 0.02 vs. 1.75 ± 0.03, 1.85 ± 0.03 vs. 1.77 ± 0.02 and 1.80 ± 0.03 vs. 1.77 ± 0.03 for the treatment vs. control groups, respectively, but the difference was significant only in the mid age parent group. These results suggest that prenatal thermal conditioning is not detrimental to broiler growth under standard rearing conditions in the absence of thermal stress. However, survival rate was improved but live weight and FCR were in some cases significantly poorer. Keywords: Heat stress, incubation, parent age, live weight, mortalitySouth African Journal of Animal Science Vol. 38 (1) 2008: pp. 58-6
Short Communication Effects of short chain fatty acid (SCFA) supplementation on performance and egg characteristics of old breeder hens
A study was conducted to determine the effect of supplementing the diet of breeder hens with a short-chain fatty acid (SCFA) premix, containing 509 g fatty acid salts/kg of which 285 g were calcium butyrate, on their eggshell characteristics and the hatching percentage of the eggs. One thousand six hundred 66-week old White Bovans laying breeder hens were used in this experiment. They were housed in eight identical pens, each containing 200 birds, and four pens were used per treatment. The SCFA premix was included at 1000 mg/kg in the treatment diet, and fed for a period of nine weeks. Responses were compared with an unsupplemented treatment. Supplementation started when the hens were 66 weeks old. From day 75 eggs were collected for the next seven weeks and the occurrence of cracked, dirty and misshapen eggs was recorded, and the hatching percentage of the eggs was determined. Eggshell strength was lower in eggs from the control (1.76 ± 0.05) than from the treatment group (2.07 ± 0.03). The percentage of eggs produced by the control group (68.6 ± 0.08) was significantly lower than that by the supplemented group (71.5 ± 0.15). Percentage of dirty, cracked and misshapen eggs, and the hatchability percentage of the control group (1.15 ± 0.03, 3.44 ± 0.05, 6.27 ± 0.03 and 88.93 ± 0.06, respectively) were also significantly lower than in the group receiving SCFA (0.47 ± 0.03, 2.21 ± 0.03, 3.81 ± 0.03 and 93.36 ± 0.05, respectively). It was concluded that dietary supplementation of SCFA to layer breeder hens from 66 weeks of age onwards improved eggshell strength, reduced the percentage of dirty, cracked and misshapen eggs and increased the hatching percentage of the eggs. The positive responses were suggested to be largely due to the butyrate in the SCFA. Keywords: Butyrate; SCFA; eggshell quality; hatching characteristics South African Journal of Animal Science Vol. 37 (3) 2007: pp.158-16
Recent Developments and Characterization Techniques in 3D printing of Corneal Stroma Tissue
Corneal stroma has a significant function in normal visual function. The corneal stroma is vulnerable because of being the thickest part of the cornea, as it can be affected easily by infections or injuries. Any problems on corneal stroma can result in blindness. Donor shortage for corneal transplantation is one of the main issues in corneal transplantation. To address this issue, the corneal tissue engineering focuses on replacing injured tissues and repairing normal functions. Currently, there are no available, engineered corneal tissues for widely accepted routine clinical treatment, but new emerging 3D printing applications are being recognized as a promising option. Recent in vitro researches revealed that the biocompatibility and regeneration possessions of 3D-printed hydrogels outperformed conventional tissue engineering approaches. The goal of this review is to highlight the current developments in the characterization of 3D cell-free and bioprinted hydrogels
Smart meter data-driven voltage forecasting model for a real distribution network based on SCO-MLP
Advanced metering infrastructure like smart meter technology has enabled the collection of high-resolution data on voltage, active, and reactive power consumption from end-users in real-time. This paper introduces a new machine learning model, named Single Candidate Optimizer (SCO) - Multi-layer perceptron (MLP), for accurate node voltage forecasting in low voltage (LV) distribution networks with high penetrations of low-carbon technologies. The proposed model utilizes historical active and reactive power measurements in one-minute resolution from smart meters to predict node voltage time series values without requiring the networkâs electrical model topology and parameters. The computational performance of the MLP framework is improved with the SCO algorithm, which reduces the number of required iterations while maintaining accuracy. The modelâs performance is evaluated with numerical metrics and compared against Particle Swarm optimization (PSO) and Differential Evolution (DE)-based models, revealing that the proposed model outperforms both, exhibiting a promising voltage forecasting capability with an average deviation of 1.296 volts relative to the measured values. Overall, this study demonstrates the potential of machine learning and smart meter data for enhancing the stability and efficiency of LV distribution networks
Gas and seismicity within the Istanbul seismic gap
Understanding micro-seismicity is a critical question for earthquake hazard
assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the
seismicity along the submerged section of North Anatolian Fault within the Sea
of Marmara (comprising the âIstanbul seismic gapâ) has been extensively
studied in order to infer its mechanical behaviour (creeping vs locked). So
far, the seismicity has been interpreted only in terms of being tectonic-
driven, although the Main Marmara Fault (MMF) is known to strike across
multiple hydrocarbon gas sources. Here, we show that a large number of the
aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the
western Sea of Marmara, occurred within a zone of gas overpressuring in the
1.5â5âkm depth range, from where pressurized gas is expected to migrate along
the MMF, up to the surface sediment layers. Hence, gas-related processes
should also be considered for a complete interpretation of the micro-
seismicity (~Mâ<â3) within the Istanbul offshore domain
Kinematics of the East Anatolian Fault Zone between Turkoglu (Kahramanmaras) and Celikhan (Adiyaman), eastern Turkey
Tajik Basin: A composite record of sedimentary basin evolution in response to tectonics in the Pamir
Investigation of a >6âkmâthick succession of Cretaceous to Cenozoic sedimentary rocks in the Tajik Basin reveals that this depocentre consists of three stacked basin systems that are interpreted to reflect different mechanisms of subsidence associated with tectonics in the Pamir Mountains: a Lower to midâCretaceous succession, an Upper CretaceousâLower Eocene succession and an EoceneâNeogene succession. The Lower to midâCretaceous succession consists of fluvial deposits that were primarily derived from the Triassic KarakulâMazar subductionâaccretion complex in the northern Pamir. This succession is characterized by a convexâup (accelerating) subsidence curve, thickens towards the Pamir and is interpreted as a retroarc foreland basin system associated with northward subduction of Tethyan oceanic lithosphere. The Upper Cretaceous to early Eocene succession consists of fineâgrained, marginal marine and sabkha deposits. The succession is characterized by a concaveâup subsidence curve. Regionally extensive limestone beds in the succession are consistent with late stage thermal relaxation and relative seaâlevel rise following lithospheric extension, potentially in response to Tethyan slab rollback/foundering. The Upper Cretaceousâearly Eocene succession is capped by a middle Eocene to early Oligocene (ca. 50â30 Ma) disconformity, which is interpreted to record the passage of a flexural forebulge. The disconformity is represented by a depositional hiatus, which is 10â30 Myr younger than estimates for the initiation of IndiaâAsia collision and overlaps in age with the start of prograde metamorphism recorded in the Pamir gneiss domes. Overlying the disconformity, a >4âkmâthick upper EoceneâNeogene succession displays a classic, coarsening upward unroofing sequence characterized by accelerating subsidence, which is interpreted as a retroâforeland basin associated with crustal thickening of the Pamir during IndiaâAsia collision. Thus, the Tajik Basin provides an example of a longâlived composite basin in a retrowedge position that displays a sensitivity to plate margin processes. Subsidence, sediment accumulation and basinâforming mechanisms are influenced by subduction dynamics, including periods of slabâshallowing and retreat
Investigating P- and S-wave velocity structure beneath the Marmara region (Turkey) and the surrounding area from local earthquake tomography
26th Annual Computational Neuroscience Meeting (CNS*2017): Part 3 - Meeting Abstracts - Antwerp, Belgium. 15â20 July 2017
This work was produced as part of the activities of FAPESP Research,\ud
Disseminations and Innovation Center for Neuromathematics (grant\ud
2013/07699-0, S. Paulo Research Foundation). NLK is supported by a\ud
FAPESP postdoctoral fellowship (grant 2016/03855-5). ACR is partially\ud
supported by a CNPq fellowship (grant 306251/2014-0)
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