Shape optimization of disc-type flywheels

Techniques were developed for presenting an analytical and graphical means for selecting an optimum flywheel system design, based on system requirements, geometric constraints, and weight limitations. The techniques for creating an analytical solution are formulated from energy and structural principals. The resulting flywheel design relates stress and strain pattern distribution, operating speeds, geometry, and specific energy levels. The design techniques incorporate the lowest stressed flywheel for any particular application and achieve the highest specific energy per unit flywheel weight possible. Stress and strain contour mapping and sectional profile plotting reflect the results of the structural behavior manifested under rotating conditions. This approach toward flywheel design is applicable to any metal flywheel, and permits the selection of the flywheel design to be based solely on the criteria of the system requirements that must be met, those that must be optimized, and those system parameters that may be permitted to vary

Use of faeces as an alternative inoculum to caecal content to study in vitro feed digestibility in domesticated ostriches (Struthio camelus var. domesticus)

In order to find an alternative source of inoculum to caecal content for studying the in vitro feed digestibility in domesticated ostriches (Struthio camelus var. domesticus), caecal content and faeces of 4 male birds were used as inocula for an in vitro gas production trial. 2. About 1 g of each of 5 substrates (maize silage, CS; alfalfa hay, AH; barley, BG; soybean meal, SM; beet pulp, BP) was weighed, in quadruplicate per inoculum, in 120 ml flasks; 75 ml of anaerobic medium and 4ml of reducing solution were added and flasks were kept at 39C. Caecal content and faeces were diluted respectively 1 : 2 (CI) and 1 : 4 (FI) with an anaerobic medium and were injected into the respective flasks (10 ml). 3. Gas production was recorded 22 times up to 120 h of incubation and fermentation characteristics (for instance, degraded organic matter, OMd; potential gas production, A; maximum fermentation rate, Rmax; time at which it is reached, Tmax; pH; volatile fatty acid, VFA; ammonia) were studied for each inoculum and substrate. 4. CI and FI showed significant differences in Tmax (1637 vs 1847 h, respectively), propionic (1647 vs 1207 mmoles/l) and butyric acid (650 vs 798 mmoles/l) and ammonia concentration (1718 vs 1995 mmoles/l). The substrates, according to their chemical composition, showed different fermentation characteristics. However, the regression equations able to estimate some fermentation characteristics of the caecum from those of faeces were statistically significant and showed R2-values ranging from 087 to 099. 5. The differences in fermentation pathways of the two inocula did not appear to influence the rate and extent of OM digestion. Faecal fermentation predicted rates and extent of OM digestion by caecal fermentation in ostriches; consequently, the faeces could be considered as an alternative to caecal content to study feed digestibility in the species, although there is a need to undertake further research. INTRODUCTION To obtain a useful feed value, it is necessary to determine digestibility specifically for ostriches, where the nutritive value of feeds used for diet formulation is very often erroneously determined using poultry. The ostrich caecum provides a suitable environment for the fermentation of dietary fibre. Feed digestibility of ostriches in vivo has been determine

Effect of mannan oligosaccharides on rabbit performance, digestibility and rectal Bacterial anaerobic populations during an episode of epizootic rabbit enteropathy

[EN] The effect of three levels of mannan oligosaccharides (MOS at 0.5, 1.0 and 1.5 g/kg diet) compared to dietary antibiotic supplementation (ANT, colistin sulphate 144, tylosin 100 and oxytetracycline 1000 ppm) and to a diet without MOS or medication (control group) were studied on 5 groups of rabbits (n=342 cages/group and 2 rabbits/cage) from weaning (35 d) to 60 d of age in a farm with an anamnestic history of Epizootic Rabbit Enteropathy (ERE). Mortality rate was recorded daily. Thirty two cages per group were randomly chosen to record growth performance and rectal anaerobic microbial population. Live weight and feed intake were recorded weekly. At 49 d of age rectal swabs were collected with cotton swabs from 8 rabbits per group and the anaerobic microbial population was counted. Feed digestibility was determined per cage using acid insoluble ash as an internal marker, collecting faeces from 57 to 59 d of age. An episode of ERE occurred during the second and the third week of the trial. The control group showed a high mortality rate during the fattening period (78%) and was not considered for further measurements. Total mortality rate was higher (P<0.05) for rabbits fed antibiotics (34.2%) than for those fed MOS (17.7, 7.75 and 17.1 %, for MOS at 0.5, 1.0 and 1.5 g/kg diet, respectively), with the lowest mortality rate being for those with a 1.0 g MOS/kg diet. Medicated rabbits showed similar growth rates compared to the average of those fed MOS diets (38.6 g/d on average), but impaired feed conversion ratio (FCR) and nutrient digestibility (P<0.003). Rabbits fed MOS at 1.0 g/kg showed better growth rates, FCR and nutrient digestibility (P<0.01) than those fed 1.5 g/kg MOS. Total anaerobic and Clostridium spp. counts were higher in medicated animals compared to those fed MOS, with those fed 1 g/kg MOS showing the lowest value (P<0.001). Under critical conditions due to an episode of ERE, a concentration of 1.0 g/kg MOS in the diet, could reduce rabbit mortality and improve growth performance.Bovera, F.; Nizza, A.; Marono, S.; Mallardo, K.; Piccolo, G.; Tudisco, R.; De Martino, L.... (2010). Effect of mannan oligosaccharides on rabbit performance, digestibility and rectal Bacterial anaerobic populations during an episode of epizootic rabbit enteropathy. World Rabbit Science. 18(1):9-16. doi:10.4995/wrs.2010.18.0291618

Effect of stocking density and protein/fat ratio of the diet on growth of Dover sole (Solea solea)

250 soles (30g initial weight) were randomly placed in 12 experimental tanks at the Discizia's aquaculture marine station. They were reared at 2 different stocking densities (2.3 and 1.3kg/m2 corresponding to 40% and 25% of the bottom surface area covered by fish) and fed on 2 diets with different protein/fat ratio (50% and 54% crude protein and 21% and 18% total lipid, respectively for diets A and B) with triplicate tanks per treatment. The trial lasted 120 days. Fish stocked at the lower density resulted in significantly higher weight gain than fish reared at 2.3 kg/m2 (29.0±7.3 g vs 20.3±8.0g; P<0.01) with a specific growth rate (SGR) of 0.54±0.09 and 0.42±0.13, respectively. Feed conversion rate (FCR) was improved at the lower density (1.8 vs 2.4, P<0.01). The chemical composition of the test diets significantly affected the growth performance of sole. Diet B led to a higher final weight (59.7 vs 50.8g; P<0.01) and better feed utilisation (FCR: 1.8 vs 2.4, P<0.01). These results confirm the necessity to ensure an adequate space for the growing sole and suggest the need for high protein diets to meet sole's requirements

Effect of mannanoligosaccharides supplementation on caecal microbial activity of rabbits

A total of 200 weaned (35 days) hybrid Hyla rabbits were randomly divided among five groups housed in bicellular cages (20 cages per group). Between 35 and 60 days of age, the groups were submitted to the following treatments: group ANT (positive control) fed a basal diet supplemented with antibiotics (colistin sulphate, 144 mg/kg; tylosin, 100 mg/kg; and oxytetracyclin, 1000 mg/kg); groups MOS-0.5, MOS-1.0 and MOS-1.5 fed the basal diet supplemented with 0.5, 1.0 and 1.5 g/kg mannanoligosaccharides (MOS), respectively; another group fed the basal diet without antibiotics or mannanoligosaccarides supplementation (negative control). Along the trial, an episode of epizootyc rabbit enteropathy occurs so that in the control group mortality rate was very high (78%) and survivor rabbits showed severe symptoms of disease (diarrhoea). Thus, the control group was discarded from the trial. At 60 days of age, samples of caecal content were collected from 10 rabbits per group and used as inocula for an in vitro gas production trial. At the end of fermentation (120 h of incubation), organic matter digestibility (OMd), cumulative gas production, fermentation kinetics, pH, volatile fatty acid (VFA) and NH3 productions were measured. Inoculum from MOS-1.0 rabbits showed the significant higher values of OMd (64.21%, P &lt; 0.05), gas production (262.32 ml/g, P &lt; 0.05), acetate (96.99 mmol/g OM, P &lt; 0.05) and butyrate (26.21 mmol/g OM, P &lt; 0.05) than the other groups. Slight differences were recorded among the groups ANT, MOS-0.5 and MOS-1.5. In addition, branched chain acids, in proportion to total VFAs, were significantly higher in MOS-1.0 inoculum (0.04, P &lt; 0.05). MOS are able to affect fermentation activity of caecal micro-organism, but their activities seem not proportional to their level in the diet. Copyright © The Animal Consortium 2010

Detection of plant species-specific dna (barley and soybean) in blood, muscle tissue, organs and gastrointestinal contents of rabbit

The aim of this study was to detect plant DNA sequences from low copy number genes of barley grain and soybean meal, the latter being subjected to solvent extraction process, in blood, liver, kidney, spleen, muscle tissue and digesta (duodenum, caecum and faeces from rectal ampulla) of rabbits. For fattening, Hyla rabbits (20 males and 20 females) were fed a diet including barley grain (15%) and soybean meal (12%). Animals were slaughtered at 74 d of age (2 ± 0.2 kg live weight) and samples collected from each animal. The quality of each DNA sample was verified using the UNIV P/Q primers used to amplify a mammalian specifi c portion of mtDNA 16S rRNA gene. The presence of plant DNA was subsequently ascertained on the same DNA samples, as well as on barley and soybean (control). Two classes of plant DNA sequences were monitored via real-time PCR, using SYBR(R) Green I Dye: a high copy number chloroplast gene (trnl) and a low copy number specific for barley (metal-dependent hydrolase-like protein) and soybean (lectin) genes. Melting curve analysis was used to identify the PCR products. The chloroplast fragment detection frequency was higher (P<0.01) in muscle (90%), liver (80%), kidney (80%) and spleen (80%) than in blood (40%) and digesta samples. In the latter, chloroplast DNA was found in 40 and 30% of duodenum and caecum contents respectively, and in 30% of faeces. The specificity of the amplicons obtained was checked by sequencing and annotation. In the samples positive for chloroplast fragments, the frequency of detection of barley specific sequence was higher (P<0.01) in liver (62.5%), kidney (62.5%), spleen (62.5%) and digesta (100%) than in blood (25%) and muscle (22.2%) samples. The soybean lectin gene was not detected in animal samples, although it was seen in plant samples. Results confirm that, except for gastrointestinal tract (GIT), plant single copy genes are more difficult to identify in animal samples.Tudisco, R.; Calabrò, S.; Bovera, F.; Cutrignelli, M.; Nizza, A.; Piccolo, V.; Infascelli, F. (2010). Detection of plant species-specific dna (barley and soybean) in blood, muscle tissue, organs and gastrointestinal contents of rabbit. World Rabbit Science. 18(2). doi:10.4995/WRS.2010.18.1118

Comparison of caecal and faeces fermentation characteristics of ostrich by in vitro gas production technique

To compare caecal and faecal fermentation characteristics, ostrich caecal content (CI) and faeces (FI) were used as inocula for an in vitro gas production trial in which four substrates (dehydrated alfalfa, alfalfa hay, maize and a commercial concentrate) were tested. The fermentation characteristics (degraded organic matter, OMd; potential gas production, A; acetate; branched chain proportion, BCP) were studied by inoculum and substrate. CI and FI showed significant differences for almost all the fermentation parameters, and CI had higher values than FI for OMd (76.83 vs. 72.79%, p&lt;0.01), A (250.3 vs. 229.3 ml/g, p&lt;0.01), acetate (57.91 vs. 53.20 mmol/l, p&lt;0.01) and BCP (0.031 vs. 0.027, p&lt;0.05). CI and FI showed differences in carbohydrates and protein fermentation, but the interaction between the tested effects was not significant. The regression equations to estimate caecal fermentation characteristics from faeces suggest the possibility to use faeces as inoculum alternative to faeces. © 2011 Taylor &amp; Francis

Quality of eggs from Lohmann Brown Classic laying hens fed black soldier fly meal as substitute for soya bean

Soya bean is the main protein source in poultry feed but rising prices make an alternative protein source necessary. Insects, such as the black soldier fly (Hermetia illucens), may be an attractive solution for hens, although little information is available on their effect on egg quality. The present study aims to fill this gap by testing the effect of 100% replacement of soya bean with H. illucens larva meal in the diet of Lohmann Brown Classic laying hens for 21 weeks. At the end of the trial, the eggs were characterized for parameters such as weight, colour, proximate composition of albumen and yolk, and content of carotenoids, tocopherols and cholesterol. The fatty acid profile of yolks was also determined. Hens fed the insect-based diet produced eggs (HIM group) with a higher proportion of yolk than the group fed the soya bean-based diet (SBM group). HIM was associated with redder yolks (red index 5.63 v. 1.36) than SBM. HIM yolks were richer in γ-tocopherol (4.0 against 2.4 mg/kg), lutein (8.6 against 4.9 mg/kg), β-carotene (0.33 against 0.19 mg/kg) and total carotenoids (15 against 10.5 mg/kg) than SBM yolks. The fatty acid composition of HIM yolks was almost identical to that of SBM yolks. Finally, HIM yolks contained 11% less cholesterol than SBM yolks. These results suggest that H. illucens larva meal is a suitable total substitute for soya bean meal in the diet of Lohmann Brown Classic laying hens. A sustainable alternative to the plant protein source therefore seems feasible