Ammonia and pH effects on some metabolic parameters and gill histology of silver catfish, Rhamdia quelen (Heptapteridae)     

Denise dos S. Miron  Bibiana Moraes  Alexssandro G. Becker  Mrcia Crestani  Roslia Spanevello  Vania L. Loro  Bernardo Baldisserotto 《Aquaculture (Amsterdam, Netherlands)》2008,277(3-4):192-196

The aim of the present study was to assess the effect of ammonia exposure at different pH on survivorship and metabolic parameters in the liver, muscle and gill histology of silver catfish (Rhamdia quelen). The 96 h-LC50 of un-ionized ammonia (mg L^− 1) at pH 6.0, 7.5 and 8.2 were: 0.44 (C.I. 0.38–0.49), 1.45 (C.I. 1.25–1.65) and 2.09 (C.I. 1.85–2.36), respectively. Survival of juveniles exposed to different ammonia levels was altered by pH, and fish exposed to all ammonia levels and different pH showed muscle glucose, muscle and liver glycogen reduction. Liver glucose and muscle and liver lactate levels increased in all fish exposed to ammonia as compared to the control. Exposure to waterborne ammonia increased total ammonia levels in both tissues and also induced gill epithelium damages such as lamellar fusion and edema as compared with controls at different pH. Silver catfish exposed to pH 6.0 and different NH₃ levels presented significantly higher hepatic glucose and protein levels when compared to those maintained at low NH₃ levels. Juveniles exposed to NH₃ levels at pH 7.5 and 8.2 showed lower hepatic protein levels compared to those maintained at low NH₃ levels. These parameters are indicative of pH dependence on ammonia toxicity in silver catfish. The metabolic parameters and gill histology may be used as early indicators of ammonia toxicity in silver catfish.  相似文献   

Net ion fluxes in the facultative air-breather <Emphasis Type="Italic">Hoplosternum littorale</Emphasis> (tamoata) and the obligate air-breather <Emphasis Type="Italic">Arapaima gigas</Emphasis> (pirarucu) exposed to different Amazonian waters     

Baldisserotto B  Copatti CE  Gomes LC  Chagas EC  Brinn RP  Roubach R 《Fish physiology and biochemistry》2008,34(4):405-412

Fishes that live in the Amazon environment may be exposed to several kinds of water: black water (BW), acidic black water (pH 3.5) (ABW) and white water (WW), among others. The aim of the present study was to analyze net ion fluxes in the facultative air-breather Hoplosternum littorale (tamoata) and the obligate air-breather Arapaima gigas (pirarucu) exposed to different types of water. Fishes were acclimated in well water and later placed in individual chambers containing one type of water for ion flux measurements. After 4 h, the water in the chambers was replaced by a different type of water. The transfer of both species to ABW (independent of previous water exposure) increased net ion loss. Tamoatas transferred from ABW to BW or WW presented a net ion influx, but pirarucus showed only small changes on net ion efflux. These results allow us to conclude that tamoatas and pirarucus present differences in terms of ion regulation but that the general aspects of the ion flux are similar: (1) exposure to ABW led to net ion loss; (2) transfer from BW to WW or vice-versa induced only minor changes on net ion fluxes. These observations demonstrate that any osmoregulatory difficulties encountered by either species during changes between these latter two waters can be easily overcome.  相似文献   

Protease Treatment to Improve Ethanol Fermentation in Modified Dry Grind Corn Processes     

Bernardo C. Vidal  Kent D. Rausch  M. E. Tumbleson  Vijay Singh 《Cereal Chemistry》2009,86(3):323-328

To improve fractionation efficiency in modified dry grind corn processes, we evaluated the effectiveness of protease treatment in reducing residual starch in endosperm fiber. Three schemes of protease treatment were conducted in three processes: 1) enzymatic milling or E‐Mill, 2) dry fractionation with raw starch fermentation or dry RS, and 3) dry fractionation with conventional fermentation or dry conv. Kinetics of free amino nitrogen production were similar in both dry and wet fractionation (E‐Mill), indicating that proteolysis was effective in all three schemes. At the end of fermentation, endosperm fiber was recovered and its residual starch measured. Using protease treatment, residual starch in the endosperm fiber was reduced by 1.9% w/w (22% relative reduction) in dry conv and 1.7% w/w (8% relative reduction) in dry RS, while no reduction was observed in the E‐Mill process. Protease treatment increased ethanol production rates early in fermentation (≤24 hr) but final ethanol concentrations were unaffected in both dry RS and E‐Mill. In dry conv, the addition of protease resulted in a decline in final ethanol concentration by 0.3% v/v, as well as a higher variability in liquefaction product concentration (higher standard deviations in the glucose and maltose yields). Protease treatment can be used effectively to enhance modified dry grind processes.  相似文献   

Stress response in silver catfish (Rhamdia quelen) exposed to the essential oil of Hesperozygis ringens     

Cândida Toni  Juan Antonio Martos-Sitcha  Ignacio Ruiz-Jarabo  Juan Miguel Mancera  Gonzalo Martínez-Rodríguez  Carlos Garrido Pinheiro  Berta Maria Heinzmann  Bernardo Baldisserotto 《Fish physiology and biochemistry》2015,41(1):129-138

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Relationship between a nondestructive and an extraction method for measuring chlorophyll contents in cowpea leaves     

Bernardo Murillo‐Amador  Narciso Ysac Ávila‐Serrano  José Luis García‐Hernández  Raúl López‐Aguilar  Enrique Troyo‐Diéguez  Cengiz Kaya 《植物养料与土壤学杂志》2004,167(3):363-364

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Compositional nutrient diagnosis and main nutrient interactions in yellow pepper grown on desert calcareous soils     

Jos Luis García‐Hernndez  Ricardo David Valdez‐Cepeda  Bernardo Murillo‐Amador  Alejandra Nieto‐Garibay  Luis Felipe Beltrn‐Morales  Rafael Magallanes‐Quintanar  Enrique Troyo‐Diguez 《植物养料与土壤学杂志》2004,167(4):509-515

Mineral‐nutrient stress is one of the main factors limiting crop production, especially in arid lands. The mineral requirement of a crop is difficult to determine, and the interpretation of foliar chemistry composition is not easy. This study was conducted to compute the minimum yield target for fresh fruit of yellow pepper (Capsicum annuum L.) and the corresponding Compositional Nutrient Diagnosis (CND) as well as to identify significant nutrient interactions of this crop in desert calcareous soils. Preliminary CND norms were developed using a cumulative variance‐ratio function and the chi‐square distribution function. From a small database, we computed means and standard deviations of row‐centered log ratios, V_X, of five nutrients (N, P, K, Ca, and Mg) and a filling value, R, which comprises all nutrients not chemically analyzed and quantified them in 54 foliar samples of the popular yellow pepper cv. ‘Santa Fé’. This cultivar is widely grown in northwest Mexico under arid conditions. These norms are associated to fresh fruit yields higher than 15.04 t ha^–1. Principal‐component analyses, performed using estimated CND nutrient indexes, allowed us to identify four interactions: negative P‐Ca, P‐Mg, and N‐K, and positive Ca‐Mg. Pepper plants growing on calcareous soils tend to take up more Ca and Mg than considered as optimum in other soil conditions.  相似文献   

Characterization of age-related changes in bovine CD8+ T-cells     

Hogg AE  Parsons K  Taylor G  Worth A  Beverley P  Howard CJ  Villarreal-Ramos B 《Veterinary immunology and immunopathology》2011,140(1-2):47-54

Evaluation of the changes induced by immunological interventions requires a baseline against which to compare those changes. The age-related changes in the CD8(+) T-cell population of cattle were studied. The results indicate that CD8(+) T-cells could be divided into γ/δ TCR1(+) and γ/δ TCR1(-) according to their expression of the γ/δ T-cell receptor. As a proportion, the CD8(+) γ/δ TCR1(+) population appears to increase with age. Within the CD8(+)γ/δ TCR1(-) a population of cells expressing a profile of surface molecules previously associated with effector memory T cells (CD45RO(+), CD62L(-), CD27(-), CD45RA(-) and CD28(-)) increases with age. Furthermore, a parallel increase with age in the proportion of CD8(+)CD45RO(+) T cells that express the cytotoxic granule protein perforin was observed. In peripheral tissues, namely lungs, it was found that the majority of CD8(+) T cells present expressed a phenotype indicative of previously primed T cells (high expression of CD45RO and perforin). In contrast, only a small population of memory CD8(+) T cells was present in lymphoid tissue where most of the CD8(+) T cells expressed a na?ve phenotype. In conclusion, in cattle, like in human, CD8(+) T cells that express a phenotype associated with antigen experience accumulate with age that may play a role in immunocompetence as the individual ages.  相似文献   

Segmented regression to describe cumulative milk production of grazing dual-purpose Holstein-Zebu cows     

Castillo-Gallegos  Epigmenio  Marín-Mejía  Bernardo de Jesús 《Tropical animal health and production》2019,51(4):809-818

The objective of this study was to compare the fit of seven functions to cumulative daily milk yield records of grazing F1 (Holstein × Zebu) cows in a dual-purpose cattle production unit of the Mexican tropics. Fifty-seven lactations from cows that calved from 1998 to 2001 were used. The functions were quadratic without intercept, three with two segments (both segments linear, the first segment quadratic and the second linear, and both segments quadratic), and three classical growth functions (Gompertz, logistic, and Richards). The Akaike information criterion corrected (AIC_C) was used as criterion of fit, being the function with the best fit the one with the lowest AIC_C value. The best fit was for the segmented function with both segments quadratic, followed closely by the Richards function. The derivatives of these functions give the daily milk yield curve (kg/cow/day), so the former results in a straight line per segment and the latter in the usual shape of the typical lactation. However, as cumulative records produce a monotonic increasing line, neither function can distinguish a priori the presence of a lactation peak. For this reason, it is advisable to examine the common dispersion plot of daily milk yield of each cow, and if a peak is not evident, then proceed to fit the segmented function; otherwise, the function of Richards should be used. The need to study the causes for the absence of a lactation peak in tropical dual-purpose cows is highlighted.

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Immunological characteristics of experimental murine infection with Leishmania (Leishmania) amazonensis     

Pereira BA  Alves CR 《Veterinary parasitology》2008,158(4):239-255

The murine models of Leishmania infection are well-studied and suitable models for studying this disease, which, despite its incidence of nearly 2 million new cases worldwide per year and its prevalence of 12 million cases, has been a somewhat neglected disease. Data obtained using such models are important for a better understanding of the disease in humans due to similarities in physiology and the advantage provided by the uniform infection profile within each mouse strain. In this review, we focus on studies of experimental murine infection with Leishmania (Leishmania) amazonensis, a species that has been associated with infections exhibiting various clinical features in humans. Mainly, we point out and discuss reports on: the effects of variations of the inoculum (such as strain, site, and size) in the establishment and development of the infection; characteristics of the infection in distinct mouse strains; and, the effects and subversions of the infection on components of the host innate and adaptive immune responses. The results obtained in these studies show that L. (L.) amazonensis infection in mice presents some unique features and immunoregulatory mechanisms, making it an interesting model for obtaining further knowledge of potential drugs targets and immunotherapy in Leishmania infection.  相似文献   

Lack of postexposure analgesic efficacy of low concentrations of eugenol in zebrafish     

Bernardo Baldisserotto  Thaylise V. Parodi  E Don Stevens 《Veterinary anaesthesia and analgesia》2018,45(1):48-56

Objective

To test the postexposure analgesic efficacy of low doses of eugenol in zebrafish.

Study design

Prospective experimental study.

Animals

A total of 76 large adult zebrafish (Danio rerio).

Methods

Fish swimming behavior (median velocity, freeze time, high-speed swimming and distance moved in the vertical direction) was recorded in a 1.6 L video arena before and after exposure to eugenol (0, 1, 2, 5, 10 and 20 mg L^?1). In a second experiment, fish were anesthetized with 2-phenoxy-ethanol and treated with an injection of 5% acetic acid (noxious stimulus), and then exposed to 0, 1, 2 and 5 mg L^?1 eugenol. The fish swimming behavior was also recorded.

Results

The higher doses (10 and 20 mg L^?1) reduced the median velocity, high-speed swimming and distance moved in the vertical direction, and increased the freeze time. Zebrafish behavior was not altered by eugenol (1, 2 and 5 mg L^?1) after noxious stimulation.

Conclusions and clinical relevance

The change in the behavior of zebrafish associated with a noxious stimulus can be monitored and is a good model for studying analgesia in fish. Eugenol (10 and 20 mg L^?1) induced zebrafish sedation. The response after a noxious stimulus was not affected by postexposure to lower doses, and thus we cannot recommend its use as an analgesic.  相似文献