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A 3 × 2 factorial design with growing dairy-breed bulls was used to study the effects on animal performance of (1) proportion of concentrate (rolled barley) in the diet, and (2) inclusion of rapeseed meal (RSM) in the barley-based concentrate in a total mixed ration (TMR). The interactions between concentrate proportion and RSM supplement were also examined.Three feeding experiments comprised in total of 84 Finnish Ayrshire bulls and 6 Friesian bulls. The bulls were fed TMR ad libitum. The three concentrate proportions were 300 (L), 500 (M) and 700 (H) g/kg dry matter (DM), fed without RSM (RSM−) or with RSM (RSM+). Rapeseed meal was given so that the crude protein (CP) content of the concentrate was raised to 160 g/kg DM in the RSM+ diets. In the RSM− diets the CP content of the concentrate was 128 g/kg DM, so the CP content increased 25% with RSM supplementation. Increasing the proportion of concentrate led to a linear improvement in daily live weight gain (LWG) (P < 0.05), but there were no significant treatment differences in the DM intake (kg/d). Increasing the proportion of concentrate also led to significantly higher CP (P < 0.001) and phosphorus (P) (P < 0.001) supply and significantly improved DM and organic matter (OM) digestibility (P < 0.001). However, the digestibility of neutral detergent fibre (NDF) decreased (P < 0.001) as the proportion of concentrate increased. The feed conversion rate (kg DM/kg LWG) decreased significantly with increasing concentrate proportion (P < 0.001). Rapeseed meal supplement had no effect on animal performance, but the supply of CP (P < 0.01) and P (P < 0.001) was higher when RSM was included in the diet. The CP (P < 0.001) and NDF (P < 0.05) digestibilities were also higher for the RSM+ diets than for the RSM− diets. Because RSM at the concentration used did not affect animal performance, there is no reason to use RSM supplementation for finishing dairy bulls when there is good quality grass silage and barley-based concentrate in the TMR ration. This study also shows that there is a need to update the Finnish feeding recommendations for dairy-breed growing bulls, and extra calculations are needed for the energy and protein supply of growing dairy bulls. 相似文献
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We examined collembolan food preference for fungal mycelium grown on copper-contaminated medium, and the relationship between copper content, food selectivity and collembolan fitness when fed contaminated mycelium.To clarify whether collembolan food selectivity is related to fitness parameters, Folsomia candida were fed mycelium of the dark-pigmented fungus Alternaria alternata grown on medium with different copper concentrations. Copper-contaminated food (fungus grown on 50, 125, 250 and 500 μg Cu g−1 medium, fresh wt.) was offered together with untreated food for 4 weeks. F. candida fed selectively on the provided mycelium and discriminated clearly between mycelium grown on high and low levels of contamination, distinctly preferring fungus grown on medium with a total copper concentration of 50 and 125 μg g−1. In contrast, fungus grown on highly contaminated medium (250 and 500 μg g−1) was avoided. Collembolan food preference generally matched fitness parameters. Reproduction was significantly affected by the total copper concentration of the fungal growth medium. When fed their preferred mycelium, collembolan reproduction was enhanced, whereas a diet of highly contaminated mycelium (250 or 500 μg g−1) resulted in a strong decrease in reproduction. Adult survival was affected only marginally. Even though heavy metal contamination is a potential stress factor for many soil microarthropods, F. candida is able to discriminate between high and low quality food sources, and even benefits from moderately elevated copper concentrations. 相似文献
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Landscape classifications are increasingly being used in conservation planning and biodiversity management, although there is a dearth of studies actually showing concordant patterns between such classifications and biodiversity. We studied the utility of tributary and stream type classifications in accounting for the variability of invertebrate biodiversity in a boreal drainage system. We found that only weak, although significant, differences existed between the studied three tributaries and four stream types in macroinvertebrate assemblage structure, species distributions, and taxonomic richness. Further, the classification strengths, calculated as mean within-group-similarity minus mean between-group-similarity of assemblage structure, were rather low, suggesting that the a priori physical classifications did not effectively describe variability in macroinvertebrate assemblage structure. The low classification strengths likely resulted from the facts that: (i) most stream macroinvertebrate taxa show individualistic responses to environmental gradients; (ii) many taxa occur either across all stream types; or (iii) only sporadically in a given stream type; and (iv) only a few species show high fidelity to a given stream type. However, the significance of the differences in macroinvertebrate assemblage structure and taxonomic richness, as well as a bunch of effective indicator species for different stream types, suggest that such classifications could be used as a preliminary scheme for the conservation planning of running waters. This reasoning is also supported by the evidence from other studies that have found stream size and the distance to upstream lakes to shape considerably the biodiversity of various groups of stream organisms, although no single organism group is likely to show a perfect match with any classification scheme. 相似文献
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A rapid and simple immunochemical method was developed for the assessment of the creatine kinase (MM) isoenzyme [CK(MM)], a protein marker linked with animal welfare and meat quality. The one-step time-resolved immunofluorometric assay produced quantitative results from serum or whole blood samples in 20 min. The analytical limit of detection (mean + 2s) for the immunoassay was 17 ng/mL (n = 6), and the functional limit of detection for the analysis of porcine whole blood samples was 426 ng/mL (n = 24). The working range of the method was linear up to 50 micro g/mL, and the within-assay precision varied between 2.1 and 10.9%. The analysis of porcine serum samples showed that the results from the immunoassay method and colorimetric CK enzyme activity determination were highly correlated (r(2) = 0.965, n = 17, p < 0.001). The practicability of the assay was demonstrated by the analysis of 300 porcine whole blood samples in a slaughterhouse environment. 相似文献
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We examined collembolan food preference for fungal mycelium grown on copper-contaminated medium, and the relationship between copper content, food selectivity and collembolan fitness when fed contaminated mycelium.To clarify whether collembolan food selectivity is related to fitness parameters, Folsomia candida were fed mycelium of the dark-pigmented fungus Alternaria alternata grown on medium with different copper concentrations. Copper-contaminated food (fungus grown on 50, 125, 250 and 500 μg Cu g?1 medium, fresh wt.) was offered together with untreated food for 4 weeks. F. candida fed selectively on the provided mycelium and discriminated clearly between mycelium grown on high and low levels of contamination, distinctly preferring fungus grown on medium with a total copper concentration of 50 and 125 μg g?1. In contrast, fungus grown on highly contaminated medium (250 and 500 μg g?1) was avoided. Collembolan food preference generally matched fitness parameters. Reproduction was significantly affected by the total copper concentration of the fungal growth medium. When fed their preferred mycelium, collembolan reproduction was enhanced, whereas a diet of highly contaminated mycelium (250 or 500 μg g?1) resulted in a strong decrease in reproduction. Adult survival was affected only marginally. Even though heavy metal contamination is a potential stress factor for many soil microarthropods, F. candida is able to discriminate between high and low quality food sources, and even benefits from moderately elevated copper concentrations. 相似文献
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Radiative absorption enhancements due to the mixing state of atmospheric black carbon 总被引：3，自引：0，他引：3
CD Cappa TB Onasch P Massoli DR Worsnop TS Bates ES Cross P Davidovits J Hakala KL Hayden BT Jobson KR Kolesar DA Lack BM Lerner SM Li D Mellon I Nuaaman JS Olfert T Petäjä PK Quinn C Song R Subramanian EJ Williams RA Zaveri 《Science (New York, N.Y.)》2012,337(6098):1078-1081
Atmospheric black carbon (BC) warms Earth's climate, and its reduction has been targeted for near-term climate change mitigation. Models that include forcing by BC assume internal mixing with non-BC aerosol components that enhance BC absorption, often by a factor of ~2; such model estimates have yet to be clearly validated through atmospheric observations. Here, direct in situ measurements of BC absorption enhancements (E(abs)) and mixing state are reported for two California regions. The observed E(abs) is small-6% on average at 532 nm-and increases weakly with photochemical aging. The E(abs) is less than predicted from observationally constrained theoretical calculations, suggesting that many climate models may overestimate warming by BC. These ambient observations stand in contrast to laboratory measurements that show substantial E(abs) for BC are possible. 相似文献
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Z. Hedayatnasab R. Eslami-Farsani S. M. R. Khalili N. Soleimani 《Fibers and Polymers》2013,14(10):1650-1656
This paper focuses on the influence of temperature conditions and the clay contents on enhancement of mechanical characterization of polypropylene (PP) nanocomposites. The nanocomposites were prepared using the melt mixing technique in a co-rotating intermeshing twin screw extruder followed by injection moulding. Nanocomposites properties such as impact strength and ultimate tensile strength, yield strength, failure strain, Young’s modulus and toughness are calculated. The addition of clay to PP matrix was showed remarkable enhancement in mechanical properties at the temperature of 25 oC and 120 °C. Nearly 36 % and 160 % increase in the Young’s modulus and about 45 % and 62 % increase in the impact strength were observed at both room temperature (RT) and high temperature (HT), respectively. But, the tensile strength was not affected much. The basal spacing of clay in the composites was measured by X-ray diffraction (XRD). Scanning electron microscopy (SEM) was used to assess the surface morphology of the fractured surfaces and dispersion of the nanoclay. 相似文献
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Jelena Tomić Milica PojićAleksandra Torbica Slađana RakitaDragan Živančev Elizabet Janić HajnalTamara Dapčević Hadnađev Miroslav Hadnađev 《Journal of Cereal Science》2013
The main aim of this study was to determine the changes in free sulphydryl content during postharvest wheat and flour maturation. The content of free sulphydryl groups was determined from wet gluten over 50 days of wheat postharvest maturation and over 14 days of flour maturation by varying incubation temperatures (30 and 37 °C) and incubation times (0, 45, 90 and 135 min). The amount of free sulphydryl groups increased during postharvest wheat and flour maturation as well as with the increase in temperature and gluten incubation time. The additional aim of this study was to find the interrelation between the content of free sulphydryl groups and selected parameters of technological quality by means of Principal Component Analysis. During wheat/flour maturation, the strengthening of protein structure was observed manifested by the increase in gluten index and Mixolab protein network weakening (C2), and changes in dough resistance as well. The incubation temperature of 37 °C affected the weakening of protein structure manifested by the decrease in gluten index and resistance, and increase in extensibility. Strong differentiation of examined varieties in terms of selected quality indicators was observed upon pre-defined maturation period, probably due to the expression of their intrinsic properties. 相似文献
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Mohsen Khalili Marzieh Attar Rezvaneh Amirlatifi Zohreh Namira Maleki Seyyed Morteza Hoseini 《Aquaculture Research》2020,51(4):1653-1659
In the present study, common carp (Cyprinus carpio) were fed with diet supplemented with 0% (M0) or 0.5% (M0.5) myrcene for 6 week and exposed to ambient copper (0.2 mg/L) for further 2 weeks. Gene expressions of superoxide dismutase (sod), catalase (cat), glutathione peroxidase (gpx), glutathione reductase (gr) and glutathione S‐transferase (gst) were assayed in the fish brain and kidney, and thiobarbituric reactive substance (TBARS) levels were determined in blood plasma. The results showed that there was no significant difference in TBARS levels between the M0 and M0.5 treatments, before the copper exposure; however, the M0 had significantly higher TBARS levels compared to the M0.5, after the copper exposure. The antioxidant genes showed different patterns in the fish brain and kidney. The genes were up‐regulated in the fish brain by dietary myrcene and copper exposure. However, in the fish kidney, the M0.5 treatment showed no change in sod, cat, gpx before and after the copper exposure. The results suggest that myrcene is capable to induce antioxidant enzymes that prepare the fish for a further oxidative condition (i.e. copper exposure). Dietary myrcene at 0.5% level is suggested for common carp before treatment with copper sulphate. 相似文献