Seasonal variation in osmoregulatory and metabolic parameters in earthen pond-cultured gilthead sea bream Sparus auratus     

Luis Vargas-Chacoff  Francisco J Arjona  Ignacio Ruiz-Jarabo  Inês Páscoa  Odete Gonçalves  María P Martín del Río  & Juan Miguel Mancera 《Aquaculture Research》2009,40(11):1279-1290

Seasonal variations in osmoregulatory and metabolic parameters were assessed in juvenile gilthead sea bream ( Sparus auratus ) cultured in earthen ponds under a natural photoperiod and temperature. Specimens were sampled, and the plasma, gill, kidney and liver were collected during winter 2005 and 2006 (January), spring 2005 (April), summer 2005 (July) and autumn 2005 (October). Plasma osmoregulatory parameters showed higher values in summer, while metabolic parameters presented different patterns of variations. Gill Na⁺,K⁺-ATPase activity decreased significantly in winter, while gill metabolite levels showed different patterns of variations among seasons. The enzymatic activities tested did not present a clear pattern of variation [(glutamate dehydrogenase (EC 1.4.1.2) (GDH) and hexokinase (EC 2.7.1.11) (HK)] or significant differences along seasons [glucose 6-phosphate dehydrogenase (EC 1.1.1.49)]. Kidney Na⁺,K⁺-ATPase activity decreased during summer and autumn. Different patterns of variation were observed in kidney metabolite levels while all the enzymatic activities assessed [lactate dehydrogenase-oxidase (EC 1.1.1.27) (LDH-O), HK and GDH] presented the highest values during summer. In the liver, metabolite levels and enzymatic activities did not show significant variations or present clear patterns of variation along different seasons. These results indicated seasonal variations in the osmoregulatory and metabolic parameters of different organs (blood, gill, kidney and liver) in earthen pond-cultured gilthead sea bream ( S. auratus ), which could be mainly attributed to seasonal changes in temperature.  相似文献   

Age estimation of Antarctic minke whales <Emphasis Type="Italic">Balaenoptera bonaerensis</Emphasis> based on aspartic acid racemization technique     

Genta Yasunaga  Luis A. Pastene  Takeharu Bando  Takashi Hakamada  Yoshihiro Fujise 《Fisheries Science》2017,83(6):947-954

Counting of the growth layers in the earplugs is the most accepted technique for determining chronological age of Antarctic minke whales; however, unreadable growth layers form in some individuals, especially in young animals. In this study, aspartic acid racemization (AAR) technique was developed for estimating ages in this species with the aim of complementing the age estimated using earplugs. To validate the technique and to determine the specific coefficients for age estimation, the ratio of d and l-enantiomers of aspartic acid (Asp D/L) in lens of 18 whales and 20 fetuses were analyzed and compared with earplug-based age estimates. The equation for age estimation by AAR in this species was as follows: Log_e{[1 + (Asp D/L)_act]/[1 ? (Asp D/L)_act]} = 2.30 × 10^?3 × earplug age (year) + 0.0201 (p < 0.001, r ²  = 0.918). There is a strong correlation between the age estimates by AAR and earplugs. This study was successful in developing the AAR technique for the Antarctic minke whale, and the application of this technique can complement the age estimation of this species based on earplug readings, especially for young animals with unreadable earplugs.  相似文献   

A morphological classification proposal for curimba (Prochilodus lineatus) sperm damages after cryopreservation     

Aléssio Batista Miliorini  Luis David Solis Murgas  Priscila Vieira Rosa  Guilherme Oberlender  Gilmara Junqueira Machado Pereira  Diego Vicente da Costa 《Aquaculture Research》2011,42(2):177-187

The present study evaluated some cryoprotectants and concentrations for curimba (Prochilodus lineatus) semen preservation from a simple methodology of analysis of sperm morphology. Semen of nine males was diluted (1:4) into eight cryosolutions, all of them containing 5% of BTS^? Minitüb, still comprising methanol or dimethyl sulphoxide (DMSO) at four concentrations: 5%, 7.5%, 10% and 12.5%. Morphological sperm analysis was performed on an optical microscope at × 1000 magnification. Damages on the head, midpiece and tail rest (the main and terminal portions) were investigated and classified as primary or secondary, according to the assumed influence on fertilization. There was a linear reduction in the total damages with an increase in the cryoprotectant concentration. Samples with DMSO showed the lowest percentage of fractured tails and tail stumps. The cryopreservation protocol retained the fertilizing potential of the sperm after freezing and both methanol 5% and DMSO 7.5% conferred adequate protection to the curimba sperm cells. Sperm morphology, as pointed out here, must be incorporated into routine fish sperm (cryopreserved or not) analysis once sperm defects influence fertilization directly. To the best of our knowledge, this was the first report on curimba sperm damages after cryopreservation by optical microscopy. The classification model presented in this study can be adequate to tackle fish sperm damages.  相似文献   

Bioremediation and reuse of shrimp aquaculture effluents to farm whiteleg shrimp,Litopenaeus vannamei : a first approach     

Luis R Martínez‐Córdova  José A López‐Elías  Guadalupe Leyva‐Miranda  Luis Armenta‐Ayón  Marcel Martinez‐Porchas 《Aquaculture Research》2011,42(10):1415-1423

Shrimp aquaculture effluents were bioremediated in a two‐phase system (System A) using the black clam Chione fluctifraga and the benthic microalgae Navicula sp., and then reused to farm whiteleg shrimp Litopenaeus vannamei. In the experimental design, Systems B and C had an identical structure as System A, but no clams or microalgae were added. System B received the same shrimp effluents while System C received only estuarine water. Shrimp raw effluents had a poor water quality. System A improved the water quality by decreasing the concentrations of total nitrogen, total ammonia nitrogen (TAN), nitrites, nitrates, phosphates, total suspended solids (TSS) and organic suspended solids (OSS). System B also decreased the concentration of TAN, TSS and OSS via sedimentation, but the effect was less pronounced than that observed in System A. Shrimp reared in the bioremediated effluents (System A) had better production (3166 kg ha^?1) and higher survival (89.2%) than those reared in effluents from Systems B (2610 kg ha^?1, 75.1%) and C (2874 kg ha^?1, 82.1%). It is concluded that the bioremediation system was moderately efficient and the bioremediated effluents were suitable to farm L. vannamei.  相似文献   

Monitoring of the photochemical degradation of metamitron and imidacloprid by micellar electrokinetic chromatography and differential-pulse polarography     

Jesús Cacho  Inmaculada Fierro  Luis Debn  Marisol Vega  Rafael Pardo 《Pest management science》1999,55(9):949-954

The photochemical degradation of metamitron (4-amino-4,5-dihydro-3-methyl-6-phenyl-1,2,4-triazin-5-one) and imidacloprid (1-(6-chloro-3-pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine) has been investigated by differential-pulse polarography (DPP) and micellar electrokinetic chromatography (MEKC); the degradation pathways of these pesticides were elucidated and their degradation products proposed. The electrochemical study of imidacloprid by DPP at different pH values demonstrated the occurrence of two different reduction processes; at pH 6.8, two peaks at −0.90 V and −1.38 V, respectively, were obtained, which are related to the photochemical reduction processes. The photochemical degradation of imidacloprid caused by sunlight was polarographically monitored and its degradation products elucidated. The polarographic reduction of deaminometamitron (obtained by photochemical reduction of metamitron) yielded two peaks at −0.62 and −1.37 V, which are related to the reduction of the CN bonds. The effect of sunlight on the reduction of metamitron was monitored by DPP, and an increase of the concentration of the degradation products was observed with time. MEKC with UV-visible detection was used to separate the pesticides and the products of their photochemical degradation, which were identified in combination with DPP. © 1999 Society of Chemical Industry  相似文献   

Evaluation of an Analytical Method for an in-vitro Study of Degradation of Organochlorine Compounds by ‘Meat Starter’ Micro-organisms     

Susana Bayarri  Pilar Conchello  Agustín A. Ario  Regina Lzaro  Antonio Herrera 《Pest management science》1997,50(2):120-126

The method of analysis employed in an in-vitro study on degradation of organochlorine compounds by meat starter micro-organisms was evaluated using the recommendations made by the Food and Drug Administration (FDA). Recoveries of the organochlorine pesticides α-, β- and γ-hexachlorocyclohexane, hexachlorobenzene, pp′DDE, dieldrin and the polychlorinated biphenyl PCB 153 from a mixture added to four different liquid media, tryptic soy broth, brain heart infusion, a commercial broth and a mineral salts medium, were determined. Recoveries were between 80 and 110% with all components, irrespective of the medium used, and there were no analytical interferences due to the reagent blank or to the matrix. The repeatability was very good with relative standard deviations in the range 2·5 to 11·1%. The concentration of each component of the mixture was determined by capillary GC analysis of extracts using an electron capture detector. © 1997 SCI.  相似文献   

Constraints to production and use of potato in Asia   总被引：1，自引：0，他引：1  

Luis A. Maldonado  Julia E. Wright  Gregory J. Scott 《American Journal of Potato Research》1998,75(2):71-79

To gain a better understanding of the relative importance of the problems facing expansion of potatoes in Asian countries, a questionnaire was sent to heads of National Potato Programs in which factors limiting the production and use of this crop were evaluated. This paper briefly describes the method employed to tabulate the survey results and then analyzes the findings themselves. Constraints that were consistently singled out include the high cost of seed potatoes, price instability, and viral diseases such as potato leaf roll. These results should serve to facilitate further refinement of regional research strategies for countries facing common problems.  相似文献   

Stochastic modeling of basins microtopography: analysis of spatial variability and model testing   总被引：2，自引：1，他引：1  

Mejian Bai  Di Xu  Yinong Li  Luis S. Pereira 《Irrigation Science》2010,28(2):157-172

Microtopography is among the most important factors affecting the performance of basin irrigation system due to its influence on the advance and recession processes. This study is based on field-measured surface elevation of 116 basins in North China. The spatial variability of basins microtopography was analyzed using geostatistics; the spatial structure of basins microtopography can be characterized by a spherical semivariogram model. The correlations between selected basin geometry parameters, mainly the standard deviation (S _d ) of surface elevation differences (SED), and the semivariogram parameters were calculated and allow estimating the semivariogram parameters from basin characteristics. Considering the randomness of SED and, simultaneously, its spatial dependence, a procedure was developed to model the spatial distribution of SED using Monte-Carlo generation and kriging interpolation techniques. The required number of SED generations was also estimated depending upon the S _d of SED. The SED stochastic generation model was tested by comparing the advance, recession, flow water depths and performance parameters observed in an experimental basin with those simulated using measured and model generated SED data. Results show that estimation errors from using generated data are similar to those resulting from observations. Thus, SED generated data may be used for assessing the impacts of microtopography on irrigation performance.  相似文献   

Effect of different total suspended solids levels on a Litopenaeus vannamei (Boone, 1931) BFT culture system during biofloc formation          下载免费PDF全文

Carlos Augusto Prata Gaona  Marcos Souza de Almeida  Veronica Viau  Luis Henrique Poersch  Wilson Wasielesky Jr 《Aquaculture Research》2017,48(3):1070-1079

In a Biofloc Technology System (BFT), there is constant biofloc formation and suspended solids accumulation, leading to effects on water quality parameters that may affect the growth performance of cultured shrimp. This study aimed to analyse during biofloc formation the effect of different total suspended solids (TSS) levels on water quality and the growth performance of Litopenaeus vannamei shrimp in a BFT system. A 42‐day trial was conducted with treatments of three ranges of TSS: 100–300 mg L^?1 as low (TL), 300–600 as medium (TM) and 600–1000 as high (TH). The initial concentrations of 100 (TL), 300 (TM) and 600 mg L^?1 (TH) were achieved by fertilization before starting the experiment. Litopenaeus  vannamei juveniles with an average weight of 4.54 ± 1.19 g were stocked at a density of 372 shrimp m^?3. Physical and chemical water parameters and shrimp growth performance were analysed. After 6 weeks, TSS mean concentrations were 306.37, 532.43 and 745.2 mg L^?1 for, respectively, TL, TM and TH treatments. Significant differences (P < 0.05) were observed in TSS, settleable solids, pH, alkalinity and nitrite, especially between the TL and TH treatments. Similarly, differences (P < 0.05) were observed in the growth performance parameters, specifically final weight, survival, feed conversion and productivity. The water quality parameters at lower range of total suspended solids concentration (TL) treatment resulted in a better performance of L. vannamei in the BFT system. The maintenance at range of 100–300 mg L^?1 TSS is thus important to the success of shrimp culture.  相似文献   

Effects of nursery shading on seedling quality and post-planting performance in two Mediterranean species with contrasting shade tolerance   总被引：1，自引：1，他引：0  

Jaime Puértolas  Luis F. Benito  Juan L. Pe?uelas 《New Forests》2009,38(3):295-308

In Mediterranean climates, seedlings are frequently shaded in the nursery to avoid heat damage and save water. However, the impact of this shading on the seedling quality and transplanting performance of Mediterranean species is not well known. We studied the effect of nursery shading on pre-planting features and post-planting performance of two Mediterranean tree species: the shade-intolerant pioneer Pinus halepensis and the shade-tolerant late-successional Quercus ilex. We grew one-year-old seedlings of both species under 100, 40 and 5% full sunlight. Shade had a low impact on the morphology and physiology of Q. ilex seedlings. In pines, only the deep shade treatment produced low quality seedlings with poor root development. In both species, transference to high light at planting in autumn did not impose any additional stress than that caused by frosts, but initial root growth was impaired in the two shaded treatments in pine. Post-planting growth and survival of oak seedlings showed no difference between treatments. Pine seedlings grown in deep shade showed higher mortality and lower growth after planting than those grown in full sun and intermediate light treatments, while intermediate light only reduced growth. For the nursery culture of Q. ilex seedlings, we advise using low light levels during summer to save water without impairing field performance. In P. halepensis, seedlings should be cultured under full sunlight conditions to maximize post-planting growth, but they can be cultured under intermediate light without impairing survival.  相似文献