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排序方式: 共有438条查询结果,搜索用时 273 毫秒
1.
2.
Effect of Stocking Density on Growth,Survival, and Condition of the Mexican Cichlid Cichlasoma beani
Edgar A. Aragon‐Flores Edna F. Valdez‐Hernandez Leonardo Martinez‐Cardenas Maria R. Castaeda‐Chavez Alfonso A. Gonzales‐Diaz Miriam Soria‐Barreto Javier M. J. Ruiz‐Velazco Emilio Pea‐Messina 《Journal of the World Aquaculture Society》2014,45(4):447-453
The Mexican cichlid Cichlasoma beani is currently exploited regionally as food and can be commercialized in the aquarium trade. Natural populations of C. beani may already be negatively affected by anthropogenic alteration of the areas in which it is distributed. The aim of the present study was to examine the effect on growth, survival, and condition of C. beani cultured in three stocking densities: three (D3), six (D6), and nine (D9) fish per each 40 L tank. At the end of a 6‐wk trial the fish cultured in D3 were longer, heavier, and grew faster than the rest of the treatments but their survival was the lowest compared to D6 and D9. The mortalities were caused by a strong aggressive behavior in D3. 相似文献
3.
C. W. Locuson P. Williams J. M. Adcock J. S. Daniels 《Journal of veterinary pharmacology and therapeutics》2016,39(2):122-130
The dog CYP1A2 enzyme is likely an important contributor to the metabolism of veterinary drugs. Dog CYP1A2 is expressed in liver, plus it is inducible and polymorphic, creating the potential for intersubject differences in pharmacokinetics. Hence, the ability to probe dog CYP1A2 activity and inhibition is relevant toward veterinary drug development and drug–drug interaction assessment. Previous studies have relied on human probes with questionable specificity for CYP1A2, so it was hypothesized that recombinant CYP1A2 could be used to find a specific CYP1A2 substrate. Intrinsic clearance experiments demonstrated that tizanidine was a substrate of CYP1A2. Profiling of tizanidine metabolites generated by CYP1A2 identified the imidazole metabolite that was detectable in dog plasma. The imidazole metabolite was subsequently used to evaluate tizanidine as a CYP1A2 probe. Co‐administration of the CYP1A inhibitor enrofloxacin with tizanidine significantly decreased (30%; n = 3) the formation of the imidazole metabolite vs. control experiments. As enrofloxacin is a weak inhibitor, further studies are required to confirm the sensitivity of tizanidine as an in vivo probe. However, tizanidine may be a more selective CYP1A2 probe than phenacetin when conducting in vitro studies due to the presence of other phenacetin‐metabolizing enzymes in dog liver microsomes. 相似文献
4.
High‐throughput Cryopreservation of Sperm from Sex‐reversed Southern Flounder,Paralichthys lethostigma 下载免费PDF全文
E Hu Rafael Cuevas‐Uribe Huiping Yang Robin Sanderson Adriane O. Gill Harry Daniels Terrence R. Tiersch 《Journal of the World Aquaculture Society》2016,47(4):555-565
The Southern flounder, Paralichthys lethostigma, is a valuable aquaculture fish with established markets in the USA. All‐female production in this species is an important technology for aquaculture because the females usually have body sizes twice those of males at the same age, and sex‐reversed males (genotypic XX neomales) are used for all‐female production by crossing with genetically normal females. However, sperm volume from the neomales is usually small (<0.5 mL) and limits their application for all‐female fish production. Cryopreservation of sperm from these sex‐reversed neomales will provide access on demand with increased efficiency to extend the application of neomales. The goal of this study was to develop a protocol for cryopreservation of sperm from the Southern flounder by using an automated high‐throughput processing system. The objectives were to: (1) determine the effect of osmolality on activation of sperm motility; (2) evaluate the effect of extender solutions on sperm motility capacity; (3) evaluate the acute toxicity of cryoprotectants (dimethyl sulfoxide [DMSO], propylene glycol, and polyethylene glycol) on sperm motility, and (4) estimate the effect of cooling rate on sperm cryopreservation and post‐thaw fertilization. Sperm motility was activated when osmolality was 400 mOsmol/kg or higher. Of the three extender buffers tested, HEPES4‐(2‐hydroxyethyl)‐1‐piperazineethanesulfonic acid (HEPES) at 300 mOsmol/kg resulted in better protection for sperm motility than did Hanks' balanced salt solution and Mounib solution at 300 mOsmol/kg during 7 d of refrigerated storage. After 30 min equilibration with the cryoprotectant of 15% DMSO, sperm motility was 24 ± 21% (fresh sperm motility without any cryoprotectants was 42%). After cooling at a rate of 20 C/min, post‐thaw sperm motility was 8 ± 5% and fertilization was 63 ± 40% evaluated at the 32–64 cell stage (5 × 105 sperm per egg). Overall, a protocol was developed for sperm cryopreservation in the Southern flounder with high‐throughput processing, which provides a tool to preserve the valuable genetic resources from neomale flounders, and enables germplasm repository development for the Southern flounder. 相似文献
5.
Effects of Water Hardness and Calcium: Magnesium Ratios on Reproductive Performance and Offspring Quality of Macrobrachium rosenbergii 下载免费PDF全文
Kamran Rezaei Tavabe Gholamreza Rafiee Mohammad Mehdi Shoeiry Shadab Houshmandi Michael Frinsko Harry Daniels 《Journal of the World Aquaculture Society》2015,46(5):519-530
This study evaluated the effect of specific calcium and magnesium ratios at two hardness values on reproductive performance and offspring quality of Macrobrachium rosenbergii brood‐females. Hatchery water containing 110.5 mg/L CaCO3 hardness was considered baseline as it has been used successfully to hatch and rear larvae and was used as the control treatment. At each hardness value of 150 and 190 mg/L CaCO3, four experimental water treatments were made in triplicate. Each treatment was adjusted using soluble salts (CaCl2·H2O, MgSO4·7H2O, and MgCl2·6H2O) to provide the hardness and calcium to magnesium ratios of 0:20, 20:80, 50:50, and 80:20 needed. Each of the experimental tanks (140 L) were stocked with six females and one male. The results indicated that both hardness and Ca:Mg ratios affect brood‐female reproductive qualitative parameters such as intermolt period, egg hatchability, egg dry weight, and egg‐clutch somatic index (ESI) parameters (P < 0.05) but not fecundity and eggs per spawn. The results revealed that brood‐females at 150 mg/L hardness showed greater reproductive performance than at 190 and 110.5 mg/L hardness. The findings also demonstrated that the treatment 50Ca50Mg at 150 mg/L hardness with 38.8 mg/L calcium and 12.9 mg/L magnesium had optimum reproductive performance and offspring quality for M. rosenbergii brood‐females. 相似文献
6.
Ilana Kobiler Miriam Akerman Leah Huberman Dov Prusky 《Postharvest Biology and Technology》2011,59(2):166-171
In Israel, black spot caused by Alternaria alternata is the main postharvest factor that impairs the quality and reduces the storability of persimmon fruit (Diospyros kaki cv. Triumph). The fungus infects the fruit in the orchard and remains quiescent until harvest. After harvest, the pathogen slowly colonizes the fruit during storage at 0 °C, which elicits black spot symptom development 2–3 months after storage entry. A commercial postharvest dip treatment in chlorine at 500 mg L?1, released from sodium troclosene tablets, effectively controlled black spot in fruit stored for up to 2 months. However, decay incidence increased as the length of storage was extended beyond 2.5 months. The long incubation period that precedes black spot symptom development after harvest enabled the development of a series of integrative approaches for application at the pre- and postharvest stages, in combination with the commercial chlorine dip treatment, to improve the control of black spot disease. Preharvest treatments included treatment with the cytokinin-like N1-(2-chloro-4-pyridyl)-N3-phenylurea (CPPU) 30 d after fruit set, or a single spray with the curative fungicide polyoxin B 14 d before harvest, and when one of these was applied in combination with the postharvest chlorine dip treatment, the black spot infected area was reduced by 3 and 60%, respectively, compared with the chlorine dip alone. At the postharvest stage, fogging during storage, or post-storage on-line spraying with sodium troclosene, when applied in combination with the postharvest chlorine dip, improved the percentage of marketable fruit by 2 or 10%, respectively, compared with the chlorine dip alone. The results indicate that postharvest pathogens that show a slow colonization pattern might enable the integration of pre- and postharvest disease control methods to improve quality and reduce postharvest disease development. 相似文献
7.
D. Shtienberg Miriam Zilberstaine D. Oppenheim Z. Herzog Shulamit Manulis H. Shwartz G. Kritzman 《Phytoparasitica》2001,29(2):143-154
The efficacy of oxolinic acid (at 200 and 300 μg a.i./l) and of several antibiotic compounds (streptomycin sulfate at 100 μg a.i./l, glycocide B at 700 μg a.i./l, kasugamycin at 80 μg a.i./l and gentamicin sulfate at 30 and 60 μg a.i./l) againstErwinia amylovora, the causal agent of fire blight in pears, was evaluated in 43 orchard experiments in 1997–2000 in Israel. In addition to
the above orchard experiments, the efficacy of the bactericides was tested in live experiments with artificial inoculation.
Natural fire blight symptoms were observed in 16 of the 43 experiments; in 13 of them, disease intensity and its distribution
among the experimental plots provided a basis for data analysis, leading to reliable conclusions concerning the efficacy of
the tested bactericides. Oxolinic acid at 300 μg a.i./l was highly effective againstE. amylovora and reduced disease severity significantly in all experiments, as compared with the untreated plots; however, a concentration
of 200 μg a.i./l was not effective in some cases. Among the tested antibiotics, only gentamicin sulfate was as effective as oxolinic acid.
Results of the artificial inoculation experiments corroborated those obtained in the naturally infected orchards. The pre-infection
activity of oxolinic acid was determined on blossom clusters that were sprayed with the bactericide before inoculation. Control
efficacy on blossom clusters sprayed 1–4 days before inoculation ranged from 68% to 80%, a level which did not differ significantly
from that observed on blossom clusters sprayed on the day of inoculation (80% control). The postinfection activity of oxolinic
acid was determined on blossom clusters that were sprayed with the compound after inoculation. Oxolinic acid was as effective
when applied 1 or 2 days after inoculation as when it was applied on the day of inoculation; however, application of the bactericide
3 days after inoculation no longer resulted in significant disease suppression. Oxolinic acid has been used commercially in
Israel since 1998 with appreciable success.
Contribution No. 533-00 from the Agricultural Research Organization 相似文献
8.
Growth responses and nitrogen constituents were tested in young citrus trees grown on gradually decreasing amounts of phosphorus in greenhouse solution cultures. The phosphorus concentration in dry matter of minus-P leaves dropped to a third of that in control leaves and then remained steady throughout the experiment, while the total nitrogen concentration was low at the beginning and, rising gradually, reached an enormous amount. Nitrogen estimations in minus-P leaves showed the specific dynamics of the soluble nitrogen fraction: its content was low at the onset of the deficiency, and rose rapidly due to intensive accumulation of arginine in the tissues. Under conditions of acute phosphorus deficiency, arginine constituted more than 60% of the free amino acids and arginine nitrogen above 40% of the total, while in normal leaves arginine did not exceed 8% of the free amino acids, and about 1–% of the total.Similar patterns of increased nitrogen level due to arginine accumulation were found in leaves of phosphorus-deficient grapefruit and orange trees under field conditions. 相似文献
9.
The activity of diflubenzuron against eggs ofLobesia botrana Den. & Schiff. was assayed with a dipping procedure, at 22° and 27° C. The compound was much more active at 27°C (LC-50 = 0.0072%) than at 22°C (LC-50 = 0.195%). 相似文献
10.