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991.
The dietary value of juvenile stages (gametophyte and juvenile sporophyte) of the brown macroalga Eisenia bicyclis for post-larval and juvenile abalone Haliotis diversicolor of 2.0–6.5 mm in shell length (SL) was examined and compared with that of a benthic diatom, Nitzschia sp., in laboratory experiments. Most abalone actively fed on these diets, but there were large variations in the growth rate among the diets and among the growth stages of abalone. Growth rates of abalone fed on Nitzschia sp. were highly variable within each growth stage, but showed no clear differences among growth stages. In contrast, in abalone fed gametophytes or juvenile sporophytes, growth rates linearly increased as abalone grew. Growth rates of >60 μm SL/day were observed in juveniles of >3 mm SL fed gametophytes, and juveniles of >5 mm SL fed juvenile sporophytes. These results indicate that the dietary value of the juvenile stages of E. bicyclis for the abalone changes as they grow, and with growth juvenile abalone begin to efficiently utilize gametophytes and juvenile sporophytes in that order.  相似文献   
992.
To determine the cytotype with better traits for the aquaculture practices of the dojo loach Misgurnus anguillicaudatus from the viewpoint of fish farming improvement, factorial crosses (2n♀ × 2n♂, 2n♀ × 4n♂, 4n♀ × 2n♂, 4n♀ × 4n♂) were conducted between natural diploids (D) and tetraploids (T), producing DD, DT, TD, and TT groups (female listed first). The potential benefits of the different cytotypes in culture were evaluated by comparing growth performance and survival rate for a 15-month rearing trial under the same production conditions. The average fertilization rate in DT and TT was significantly lower than in the DD and TD groups, possibly indicating the poor fertilizing capacity of the tetraploid sires. Survival rate in DT and TD was slightly lower than in DD but significantly higher than in the TT groups. Tetraploid females produced obviously larger eggs than diploids and, subsequently, significantly longer initial body length of TT and TD than DD and DT fry. However, from the second month of the growth trial, TT suffered higher mortality than other cytotypes, which significantly influenced morphometric growth parameters. The TD group exhibited superior growth performance throughout the experiment. The mean body length of DT was comparable with that of DD fish during the first 7 months but began to outgrow DD from the 9th month. This study suggests that the relatively better growth of tetraploid and higher survival rate of diploid can be integrated via inter-ploidy hybridization to get TD triploids with better culture traits.  相似文献   
993.
China and Hungary are major providers of the common carp (Cyprinus carpio L.) in East Asia and Europe respectively. However, the genetic variation and relationship of this species in the two countries have been poorly understood. In this study, mitochondrial COII‐tRNALys and D‐loop sequences were analysed to investigate the genetic structure and relationships of the representative wild and domesticated common carps distributed in China and Hungary. The results indicated that the genetic diversities of the Chinese common carps are higher than those of Hungarian common carps, and the diversities of the wild common carps are higher than those of domesticated common carps in both the countries. Analysis of molecular variance and pairwise FST demonstrated a significant genetic divergence between the Chinese and the Hungarian common carps, and between the wild and the domesticated common carps. Bayesian phylogenetic analysis and statistical parsimony network showed an obvious genetic differentiation between the Chinese and the Hungarian common carps, between the wild and the domesticated common carps. However, a few specimens and haplotypes from the Chinese wild common carps appeared in the Hungarian common carps, demonstrating that there was no absolutely isolated and possible genetic linker between the Chinese and the Hungarian common carps.  相似文献   
994.
Adult Mesenchymal Stem Cells (MSC) are cells that can be defined as multipotent cells able to differentiate into diverse lineages, under appropriate conditions. These cells have been widely used in regenerative medicine, both in preclinical and clinical settings. Initially discovered in bone marrow, MSC can now be isolated from a wide spectrum of adult and foetal tissues. Studies to evaluate the therapeutic potential of these cells are based on their ability to arrive to damaged tissues. In this paper we have done a comparative study analyzing proliferation, surface markers and OCT4, SOX9, RUNX2, PPARG genes expression in MSC cells from Bone marrow (BMMSC) and Adipose tissue (ASC). We also analyzed the role of Stem Cell Factor (SCF) on MSC proliferation and on ASCs metalloproteinases MMP-2, MMP-9 secretion. Healthy dogs were used as BMMSC donors, and ASC were collected from omentum during elective ovariohysterectomy surgery. Both cell types were cultured in IMDM medium with or without SCF, 10% Dog Serum (DS), and incubated at 38 °C with 5% CO2. Growth of BMMSCs and ASCs was exponential until 25–30 days. Flow citometry of MSCs revealed positive results for CD90 and negative for CD34, CD45 and MCH-II. Genes were evaluated by RT-PCR and metalloproteinases by zymografy. Our findings indicate morphological and immunological similarities as well as expression of genes from both origins on analyzed cells. Furthermore, SCF did not affect proliferation of MSCs, however it up-regulated MMP-2 and MMP-9 secretion in ASCs. These results suggest that metalloproteinases are possibly essential molecules pivoting migration.  相似文献   
995.
The effect of biotin supplementation on various foot lesions and hoof ceramide composition of toe (wall) and sole portions of hooves was studied in crossbred dairy cattle. Biotin supplementation was done for five months in 14 cattle at a farm and the other 14 animals kept as control. A significant decline was observed in heel erosions and sole avulsions along with total disappearance of white line fissures and double soles in the biotin supplemented cattle resulting in decrease in the overall disease score. Thin layer chromatographs of the hoof lipids revealed 11 types of ceramides in sole lipids and 6 types of ceramides in toe (wall) lipids. The ceramides were typed and identified according to their Rf values. A qualitative increase in the density of thin layer chromatographs of sole lipids was observed in biotin supplemented cattle whereas a non-significant difference in density of thin layer chromatographs of toe lipids was observed after supplementation of biotin.  相似文献   
996.
Climate change spurs havoc on social-ecological system. People and places vulnerable to climate change have been the focus of many discussions. However, in the forestry sector, limited studies have been conducted that link human vulnerability to recent initiatives, such as reducing emissions from deforestation and forest degradation or REDD+, especially in highly vulnerable countries. Using case studies from the Philippines, this paper focuses on the vulnerability of two community-based forest management (CBFM) organizations, with and without REDD+ readiness intervention, to show the impacts of climate variability and extremes. Two balance-weighted approaches, the livelihood vulnerability index and the IPCC-framework, were used in the vulnerability assessments. Results revealed high vulnerability of both CBFM organizations, although Malitbog Upland Developers for Sustainable Association (MUDSA) livelihood vulnerability is largely aggravated by its exposure to disaster, climate variability and extremes, accessibility to health facilities and water supply. The long history of CBFM implementation in both organizations have minimal contribution in enhancing the adaptive capacity of members to cope with and adapt to climate change impacts. REDD+ (readiness), does not insure reduced vulnerability to climate change, unless sustainable livelihood is achieved. As the State controls forest resources, the rights of CBFM-organizations to commercially benefit from these resources are limited, a disincentive to the development of new and viable development programs in CBFM areas, such as REDD+. This also constrains the achievement of climate resiliency.  相似文献   
997.
Yeast is a potential alternative to fish meal in diets for farmed fish, yet replacing more than 50 % of fish meal results in reduced fish growth. In a 4-week experiment, 15 rainbow trout (Oncorhynchus mykiss) were cannulated and fed three diets each week: 30 % fish meal as a control (FM); 60 % replacement of fish meal protein, on a digestible basis, with Saccharomyces cerevisiae (SC); and 60 % replacement with Wickerhamomyces anomalus and S. cerevisiae mix (WA). Blood was collected at 0, 3, 6, 12 and 24 h after feeding. In the final week, fish were exposed to a 1-min netting stressor to evaluate possible diet–stress interactions. Significant increases in pH, TCO2, HCO3 and base excess were found after fish were fed the SC and WA diets compared with FM, which elevated blood alkaline tides. Yeast ingredients had lower buffering capacity and ash content than fish meal, which explained the increase in alkaline tides. In addition, fish fed the WA diet had significantly reduced erythrocyte area and fish fed SC and WA diets had increased mean corpuscular haemoglobin levels, indicating haemolytic anaemia. Higher levels of nucleic acid in yeast-based diets and potentially higher production of reactive oxygen species were suspected of damaging haemoglobin, which require replacement by smaller immature erythrocytes. Acute stress caused the expected rise in cortisol and glucose levels, but no interaction with diet was found. These results show that replacing 60 % of fish meal protein with yeasts can induce haemolytic anaemia in rainbow trout, which may limit yeast inclusion in diets for farmed fish.  相似文献   
998.
Neosalanx taihuensis were sampled from the Tian-e-zhou Oxbow from March 2006 through November 2007. Two separate spawning seasons were identified based on the annual reproductive cycles of the females, designated as the autumn-spawning season and the spring-spawning season. Lifespan of the offspring of the spring-spawning fish was 1 year, with them dying after the subsequent spring spawning. Autumn-spawned females seem to be the offspring of the spring-spawning fish, based on monthly changes in the length–frequency distributions. Spring-mature females had higher absolute fecundity, gonadosomatic index, and relative condition factor in 2007 than in 2006. Relative condition factor of the immature female offspring of spring-spawning fish was higher in 2007 than in 2006, portending a further increase in reproductive investment during the spring spawning of 2008. The increasing reproductive investment suggests that the population of N. taihuensis in the Tian-e-zhou Oxbow may be recovering from its recent decline.  相似文献   
999.
Acute hepatopancreatic necrosis disease (AHPND) of shrimps is an important disease, first appeared in China in 2009. Since then, AHPND has caused serious drops in shrimp production (up to 20 % worldwide). Although AHPND [originally termed as acute hepatopancreatic necrosis syndrome (AHPNS)] first appeared in 2009, it was not until 2013 that a laboratory infection model was devised and the causative agent identified as certain strains of Vibrio parahaemolyticus. AHPND has caused mortality from 40 to 100 % which usually occurs early (within approximately 35 days) after stocking shrimp fry in shrimp ponds; therefore, it was initially referred to as early mortality syndrome (EMS). Confusingly, other pathogens and environmental factors also cause EMS and are often attributed to AHPND by shrimp farmers. Frequently, farmers do not send samples for confirmatory tests requiring detection of the unique histopathology at the acute stage of disease (massive sloughing of hepatopancreatic epithelial cells without any accompanying signs of a pathogen). The gross signs presumptive of AHPND (lethargy, slow growth, empty stomach and midgut, and a pale to white, atrophied hepatopancreas) are insufficient for confirmatory diagnosis. Recently, molecular detection of AHPND bacteria using PCR has been developed, which has sped up diagnosis and increased research on the causative agent, alternative detection methods, and possible therapies. We hope that this review of research progress on AHPND will serve as a useful introduction for researchers who are currently unfamiliar with AHPND, but have backgrounds in bacterial virulence, detection, and epidemiology, and may be encouraged to participate in the research effort to reduce AHPND’s impact on shrimp cultivation.  相似文献   
1000.
Every growing season, paddy fields are kept both flooded and drained for a significant period of time. As a consequence, these soils develop distinct physico-chemical characteristics. For practical reasons, these soils are mostly sampled under dry conditions, but the question arises how representative the results are for the wet growing conditions. Therefore, the apparent electrical conductivity (ECa) of a 1.4 ha alluvial paddy field located in the Brahmaputra floodplain of Bangladesh was measured in both dry and wet conditions by a sensing system using the electromagnetic induction sensor EM38, which does not require physical contact with the soil, and compared both surveys. Due to the smooth water surface under wet conditions which ensured increased stability of the sensing platform, the results of the survey showed considerably reduced micro-scale variability of ECa. Furthermore, the wet survey results more reliably furnished soil-related information mainly due to the absence of soil moisture dynamics. The differences between ECa under wet and dry conditions were attributed to differences in soil texture, mainly the sand content variation having considerable effect on soil moisture differences when flooded following drainage. Accordingly, the largest differences between ECa under wet and dry conditions were found in those parts of the field with a large sand content. Hence, the conclusion was that an ECa survey on flooded fields has an added value to precision soil management.  相似文献   
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