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1.
The effects of a limited grazing period on the performance, behaviour and milk composition of high-yielding dairy cows were examined. A total of 56 Holstein cows yielding 44.7 ± 0.42 kg/day were allocated to one of four treatments in one of two, 4-week periods. Treatments were as follows: control (C)—cows housed and offered TMR ad libitum; early grazing (EG)—cows grazed for 6 hr after morning milking then housed; delayed grazing (DG)—cows returned to housing for 1 hr after morning milking followed by grazing for 6 hr, then housed; restricted TMR (RT)—cows grazed for 6 hr after morning milking, then housed and fed TMR at 75% of ad libitum. Intake of TMR was highest in cows receiving C, intermediate in EG and DG, and lowest in RT at 26.9, 23.6, 24.7 and 20.3 kg DM/day respectively. Pasture intake was similar in cows receiving EG or DG, but was higher in RT at 2.4, 2.0 and 3.5 kg DM/day respectively. Milk yield was similar between cows receiving C, EG or DG, but lowest in RT at 45.7, 44.2, 44.9 and 41.7 kg/cow, respectively, while milk fat content of C18:3 n-3 was increased by grazing. Cows in C spent more than 55 min/day longer lying and had three additional lying bouts/day, while lying bouts were shorter than for cows receiving EG, RT or DG. It is concluded that high-yielding cows can be grazed for 6 hr/day with little impact on performance, provided TMR is available ad libitum when housed.  相似文献   
2.
Agricultural soils are important sources of greenhouse gases (GHGs). Soil properties and environmental factors have complex interactions which influence the dynamics of these GHG fluxes. Four arable and five grassland soils which represent the range of soil textures and climatic conditions of the main agricultural areas in the UK were incubated at two different moisture contents (50 or 80% water holding capacity) and with or without inorganic fertiliser application (70 kg N ha−1 ammonium nitrate) over 22 days. Emissions of N2O, CO2 and CH4 were measured twice per week by headspace gas sampling, and cumulative fluxes were calculated. Multiple regression modelling was carried out to determine which factors (soil mineral N, organic carbon and total nitrogen contents, C:N ratios, clay contents and pH) that best explained the variation in GHG fluxes. Clay, mineral N and soil C contents were found to be the most important explanatory variables controlling GHG fluxes in this study. However, none of the measured variables explained a significant amount of variation in CO2 fluxes from the arable soils. The results were generally consistent with previously published work. However, N2O emissions from the two Scottish soils were substantially more sensitive to inorganic N fertiliser application at 80% water holding capacity than the other soils, with the N2O emissions being up to 107 times higher than the other studied soils.  相似文献   
3.
One alternative to contribute to the reduction of the pressure on coral reef ecosystems brought about by an increasing demand for marine aquarium ornamentals is to improve and further develop the culture of desirable species for trade. Peppermint shrimp from the genus Lysmata are among the most intensively traded decapod in the trade and while several studies have been conducted to improve its culture, individuals obtained from culture facilities are generally paler than those collected from the wild. Because color is a fundamental component of the price tag on most marine ornamental live species, poorly colored animals command a lower price, reducing competitiveness. In this study, we evaluate the influence of tank background color (reflected light) on the morphological coloration change of Lysmata boggessi. In a 15‐d experiment, 30 individuals were exposed either to reflected‐red or white light and the relative change of coloration between initial and final moments was quantified with photography (RGB color model). At the end of the experimental period, shrimp exposed to red‐reflected light presented a more intense red coloration than those exposed to white‐reflected light. These results demonstrate that a simple change in background tank color can enhance shrimp external coloration. Such a cheap‐to‐implement procedure can support the culture of more colorful, hence more valuable ornamental shrimp that can compete with those captured from the wild.  相似文献   
4.
This study was carried out to investigate the cause of stone cell formation in pear (Pyrus pyrifolia cv. ‘Niitaka’) flesh. Potted plants grown in a glass house were subjected to water stress conditions without irrigation for 30 days from 30 days before full bloom (BFB treatment), full bloom (FB treatment) and 30 days after full bloom (AFB treatment). Control plants were drip-irrigated daily maintaining a soil matrix potential around −40 ± 5 kPa. The formation of stone cells in pear flesh increased in the FB treatment and AFB treatment plants and this tendency was sustained until the harvest season. Root activity was investigated 60 days after full bloom (DAFB) and the triphenyltetrazolium chloride (TTC) reduction potential, the formazan content and leaf water potential were investigated 30, 45, and 60 DAFB. Root activity decreased progressively due to the effect of water stress. Also, the Ca content in leaf and flesh was lower. The peroxidase activity was high in the flesh at the early stages of fruit growth and decreased at the late stages of fruit growth, and then a higher increase of peroxidase activity was observed in water-stressed fruit. The reduction in calcium content of leaf and fruit in plants under water stress may be related to the reduction of root activity and leaf water potential. The increase in peroxidase activity under water stress may be due to limited calcium absorption. Higher peroxidase activity may induce the accumulation of lignin in the cell wall and promote the formation of stone cells in pear flesh. We conclude that water stress condition during the early stages of fruit growth is one of several factors that determine the formation of stone cells in pear flesh.  相似文献   
5.
The shape of the lipid vesicle (the ratio between the maximal and the minimal diameter and the shape coefficient) of the eggs of Diplodus puntazzo and Sparus aurata is correlated with larval survival rate (%) and can be used as an egg quality marker as reported previously by Lahnsteiner and Patarnello (2005) . In the present study, this method for egg quality determination has also been validated for common dentex, Dentex dentex, after introducing several modifications in the calculation and evaluation procedure in order to obtain higher sensitivity. In the present study, it could be demonstrated that the shape of the lipid vesicle is not only correlated with the hatching rate but also with the survival rate of 1, 2 and 3 days post hatch larvae and therefore it can also be used as an indicator of larval viability at early stages of development.  相似文献   
6.
The commercial furunculosis vaccine Aquavac Furovac 5 and an autogenous vaccine, based on the challenge strain, induced immune protection in turbot, Scophthalmus maximus (L.), as shown in challenge tests 120 days post-immunization by injection (relative percentage of survival, RPS = 72-99%). This protective effect lasted for at least 6 months post-immunization at appreciable levels (RPS = 50-52%). Neither the autogenous vaccine nor the commercial vaccine was able to induce significant levels of protection against Aeromonas salmonicida in turbot when administered by immersion. Antibody levels were high or moderate in fish vaccinated by injection with the different vaccines and very low in fish vaccinated by immersion. The field results show that delivering an oral boost after the primary vaccination by injection did not enhance protection of turbot against furunculosis and that water-based (autogenous vaccine) and oil adjuvanted (Alpha Ject 1200) vaccines administered by injection conferred similar levels of protection (RPS > 80%) in turbot.  相似文献   
7.
Natural phenolic antioxidants have been tested in hake (Merluccious merluccious) microsomes as inhibitors of lipid oxidation promoted by fish muscle prooxidants: hemoglobin (Hb), enzymatic NADH-iron and nonenzymatic ascorbate-iron. The phenolics selected were as follows: (a) a grape phenolic extract (OW), (b) a fraction (IV) with isolated grape procyanidins with a medium-low degree of polymerization and galloylation percentage, (c) hydroxytyrosol obtained from olive oil byproducts, and (d) a synthetic phenolic antioxidant, propyl gallate. All compounds delayed lipid oxidation activated by Hb, enzymatic NADH-iron, and nonenzymatic ascorbate-iron, excluding hydroxytyrosol that was not an effective antioxidant on oxidation promoted by nonenzymatic iron. The relative antioxidant efficiency was independent of the prooxidant system, IV > propyl gallate > OW > hydroxytyrosol, and showed a positive correlation with their incorporation into microsomes (p < 0.05). The reducing capacity or ability for donating electrons and the chelating properties may also contribute to the antioxidant activity of phenolics, although these factors were less decisive than their affinity for incorporating into the microsomes. Conversely, the inhibition of Hb oxidation by phenolics and their polarity did not seem to play an important role on antioxidant mechanism. These results stressed the importance of incorporating the exogenous antioxidants into the membranes where are located key substances for fish lipid oxidation (highly unsaturated phospholipids, iron-reducing enzymes, and endogenous alpha-tocopherol).  相似文献   
8.
OBJECTIVE: To analyze the morphology, cytoarchitecture, and lumbosacral spinal cord projections of the red nucleus (RN) in cattle. ANIMALS: 8 healthy Friesian male calves. PROCEDURES: Anesthetized calves underwent a dorsal laminectomy at L5. Eight bilateral injections (lateral to the midline) of the neuronal retrograde fluorescent tracer fast blue (FB) were administered into the exposed lumbosacral portion of the spinal cord. A postsurgical calf survival time of 38 to 55 days was used. Following euthanasia, the midbrain and the L5-S2 spinal cord segments were removed. Nissl's method of staining was applied on paraffin-embedded and frozen sections of the midbrain. RESULTS: The mean length of the RN from the caudal to cranial end ranged from 6,680 to 8,640 microm. The magnocellular and parvicellular components of the RN were intermixed throughout the nucleus, but the former predominate at the caudal portion of the nucleus and the latter at the cranial portion with a gradual transitional zone. The FB-labeled neurons were found along the entire craniocaudal extension of the nucleus, mainly in its ventrolateral part. The number of FB-labeled neurons was determined in 4 calves, ranging from 191 to 1,469 (mean, 465). The mean cross-sectional area of the FB-labeled neurons was approximately 1,680 microm2. CONCLUSIONS AND CLINICAL RELEVANCE: In cattle, small, medium, and large RN neurons, located along the entire craniocaudal extension of the RN, contribute to the rubrospinal tract reaching the L6-S1 spinal cord segments. Thus, in cattle, as has been shown in cats, the RN parvicellular population also projects to the spinal cord.  相似文献   
9.
A 2.5-year-old male African pygmy hedgehog (Atelerix albiventris) was presented with a 2-week history of lethargy, reduced appetite, and general weakness. Based on the clinical signs and heart valve abnormalities observed during an echocardiography examination, a provisional diagnosis of endocardiosis or endocarditis was made. Immediate therapeutic intervention consisted of furosemide, pimobendan, and amoxicillin/clavulanate. Despite medical treatment, 2 weeks following presentation, the hedgehog’s physical condition deteriorated to the point that euthanasia was recommended for the patient and agreed to by its owner. A postmortem examination was performed and tissue samples submitted for histopathology revealed a final diagnosis of valvular endocardiosis and wobbly hedgehog syndrome.  相似文献   
10.
In 2012, there were exceptional blooms of D. acuminata in early spring in what appeared to be a mesoscale event affecting Western Iberia and the Bay of Biscay. The objective of this work was to identify common climatic patterns to explain the observed anomalies in two important aquaculture sites, the Galician Rías Baixas (NW Spain) and Arcachon Bay (SW France). Here, we examine climate variability through physical-biological couplings, Sea Surface Temperature (SST) anomalies and time of initiation of the upwelling season and its intensity over several decades. In 2012, the mesoscale features common to the two sites were positive anomalies in SST and unusual wind patterns. These led to an atypical predominance of upwelling in winter in the Galician Rías, and increased haline stratification associated with a southward advection of the Gironde plume in Arcachon Bay. Both scenarios promoted an early phytoplankton growth season and increased stability that enhanced D. acuminata growth. Therefore, a common climate anomaly caused exceptional blooms of D. acuminata in two distant regions through different triggering mechanisms. These results increase our capability to predict intense diarrhetic shellfish poisoning outbreaks in the early spring from observations in the preceding winter.  相似文献   
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