Early survival of marble trout Salmo marmoratus: evidence for density dependence?

Abstract –  The role of endogenous and exogenous factors in regulating population dynamics of freshwater salmonids is still a matter of debate. The aim of the present work was to assess the relative importance of density-dependent and -independent factors in determining the survival of marble trout ( Salmo marmoratus ) yearlings in two populations living in Slovenian streams (Zakojska and Gorska). The investigation was performed by combining a classical life table analysis with Monte Carlo simulation. Size-dependent fecundity was estimated by stripping wild adults in the fish farm. A significant positive relationship was found between length of marble trout females and the number of eggs produced. Egg density was the major determinant of survival from eggs to age 1+ ( σ ₀) in both streams. Residuals of the relationship between σ ₀ and egg density were positively correlated with rainfall only in Zakojska, probably because, within a certain range, more intense rainfalls increases stream flow and, consequently, suitable habitat for trout. Our study shows how density-dependent and environmental factors can interact to determine the survival of marble trout during the first year of life.     

Development of a hamster model of Chlamydophila pneumoniae infection

The purpose of the study was to evaluate haemostatic function in cattle with abomasal displacement (AD) and to reflect the occurrence of disseminated intravascular coagulation (DIC). Ten adult cattle with left displacement of abomasum (LDA) (group I), 10 adult cattle with right displacement of abomasum with volvulus (RDA) (group II) and 10 clinically healthy adult cattle (control group) were used as material. Numbers of platelets (PLT) and coagulation tests (activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), serum fibrin/fibrinogen degradation products (FDPs), fibrinogen) were measured before the surgical treatment of cattle with LDA and RDA. APTT was prolonged only in group II compared with the control and group I (p<0.05). However, when the individual values of coagulation profiles of each cow were evaluated, two cattle in group I and three cattle in group II had at least three abnormal coagulation profiles, which reflect the occurrence of DIC. These cattle died after surgical treatment. The two cattle with LDA had abnormal APTT, FDPs and PLT values; three cattle with RDA had abnormal APTT, PT, TT, FDPs and PLT values. APTT (5 cases), FDPs (5 cases) and thrombocytopenia (5 cases) were the three most common abnormal tests on coagulation profile in the cattle with LDA and RDA. The results of the study indicate that cattle with AD had a spectrum of haemostatic dysfunction and that DIC was a significant risk factor for mortality.     

Cultivation and expansion of canine Schwann cells using reexplantation

Despite the numerous available possibilities for the surgical treatment of peripheral nerve lesions found in the dog, the success of these treatments is often unsatisfactory. It has been proven that Schwann cells (SC) have a positive influence on the regeneration of nerve stumps. Implanting a guidance channel seeded with autologous SC at the lesion site could be a new therapeutic approach. The aim of this research was to investigate the in vitro cultivation and expansion of canine SC as the main requirement for the treatment referred to above. Biopsies were carried out on 17 nerve samples originating from dogs of different breed, age, gender and condition. The reexplantation method was employed, followed by dissociation using hyaluronidase, collagenase and trypsin and further expansion. The samples were divided into six groups which were treated with a varying combination of mitogens (forskolin, bovine PEX, choleratoxin, heregulin). To obtain the quantities of SC, the specimens were immunostained by a p75-antibody. By employing a growing number of agents it was possible to obtain an increase in both the quantity of cells and purity of cultures. A maximum of 16x10(5) cells per millilitre of suspension was achieved. The largest SC purity measured 27.1%. The maximum SC quantity achieved was 43.3x10(4) SC per millilitre.     

Caspase-mediated apoptosis in chicken postovulatory follicle regression

Chicken postovulatory follicle (POF) regression occurs via the process of apoptosis. However, the signals and initiator pathways responsible for regression of the POF are unknown. In the current study, we examined gene expression patterns of various caspases (caspase-1, -2 and -3) involved in apoptosis by semi-quantitative RT-PCR. The percentage of apoptotic cells during POF regression was also quantified by flow cytometry. Expression of caspase-3 mRNA was noted in the largest preovulatory follicle (F1). However, the initiator caspases (caspase-1 and -2) were not expressed in F1. During the regression of the POF, caspase-3 was activated during initial stages, whereas the initiator caspases were upregulated at the later stages (POF4 and POF5).The percentage of apoptotic cells was significantly higher during the regression of the POF. It might be possible that levels of caspase-3 mRNA do not necessarily reflect the cell’s potential for facilitating apoptosis, as activation of the caspase-3 by initiator caspases is required for its function. We presume that both caspase-1 and caspase-2 were key initiators in the regression of chicken POF and that the apoptosis-mediated regression of POFs might be similar to mammalian corpus luteum involution.     

Effects of common carp Cyprinus carpio (L.) and feed addition in rohu Labeo rohita (Hamilton) ponds on nutrient partitioning among fish, plankton and benthos

The effects of introducing common carp (CC) and of adding artificial feed to fertilized rohu ponds on water quality and nutrient accumulation efficiency were studied. All ponds were stocked with 15 000 rohu ha^?1. Treatments included ponds with rohu alone, rohu plus 5000 common carp ha^?1 and rohu plus 10 000 CC ha^?1. A comparison was also made between supplementally fed and non‐fed ponds. The overall highest nitrogen (N) and phosphorus (P) concentrations were observed in ponds with 5000 CC ha^?1, followed by ponds with 10 000 and 0 CC ha^?1. The largest fractions of N and P inputs accumulating in fish, phytoplankton and zooplankton were observed in ponds with 5000 CC ha^?1, followed by ponds with 10 000 CC ha^?1 and subsequently ponds without CC. Relatively more nutrients accumulated in benthic organisms in ponds without than in ponds with CC. A smaller fraction of the nutrient input was retained in fish, plankton and benthic organisms in ponds without CC compared with ponds with CC. Compared with 5000 CC ha^?1, stocking 10 000 CC ha^?1 can be considered as overstocking, because this leads to lower fish production and relatively less nutrients retained in plankton and benthic organisms.     

Beftallungsbrief für zwei Rottweiler Jäger

Ohne Zusammenfassung     

The concentration of ascorbic acid in different tissues of calf fetuses in 3 different development stages]

The concentration of ascorbic acid in the cerebrum and in the brain stem of bovine fetuses decreased with increasing body weight; in the cerebellum there was no change. The decrease of the concentration in the lungs, in the heart, in the kidneys, in the M. longissimus and in the M. semimembranosus in the course of the fetal growth was different. In the liver and in the adrenals the concentration in the 3 groups of fetuses with a body weight of 4.18 +/- 2.01, of 9.72 +/- 0.97 and of 17.12 +/- 2.61 kg was similar. The highest concentrations were found in the adrenals, in the testes and in the cerebrum. The functional significance of the changes in the concentration in the tissues of the bovine fetuses is discussed and compared with the results in human fetuses and in adult cattle.     

Addison's disease due to bilateral adrenal malignancy in a dog

A 12-year-old Rottweiler cross Labrador was presented with anorexia and weakness. Adrenal insufficiency was diagnosed with hyponatraemia, hyperkalaemia and undetectable resting and post-ACTH cortisol and aldosterone concentrations. The only abnormal diagnostic imaging result was bilateral adrenomegaly. Cytologic findings of liver, spleen and peripheral lymph nodes were normal. The dog responded initially to standard replacement therapy but relapsed shortly afterwards. The owners opted for euthanasia and allowed only removal of both adrenal glands. Microscopically, infiltrative polymorphic proliferations of densely packed tumour cells arranged as nests, intermingled with multifocal areas of necrosis and inflammatory cells were found. Silver staining revealed a few non-neoplastic adrenomedullary cells, whereas neoplastic cells did not stain. Immunohistochemistry was negative for neuron-specific enolase, vimentin, cytokeratin, synaptophysin, chromogranin A, S-100 protein, CD 56, 79 and 3. The final diagnosis was highly anaplastic bilateral adrenal neoplasia. This is the first report of bilateral adrenal malignancy presenting as clinical hypoadrenocorticism in a dog.     

Evaluating the effect of plant water availability on inner alpine coniferous trees based on sap flow measurements

Climate simulations anticipate an increase in mean summer temperature with synchronous decrease in summer precipitation during the course of the current century in Central Europe. As a consequence, transpiration of forest trees and stands may be altered along with soil water availability. In this study, the effect of reduced plant water availability to conifers was investigated into an open Pinus sylvestris forest (Erico-Pinetum typicum; P. sylvestris 60 %, Picea abies 20 %; and Larix decidua 20 %) within the inner alpine dry valley of the Inn River in Tyrol, Austria. For reducing plant water availability, we installed a transparent roof construction above the forest floor to prevent precipitation to reach the soil. The roofed area covered 240 m² and included 10 trees. A respective number of 11 trees served as controls in the absence of any manipulation. Roofing significantly reduced plant water availability as indicated in lower predawn needle water potentials. Sap flow density (Q _s) was 63, 47, and 24 % lower in roofed P. sylvestris, P. abies, and L. decidua trees, respectively, as compared to control trees. Our findings suggest that P. sylvestris and P. abies behaves “isohydric” as they close their stomata relatively early under conditions of reduced plant water availability and thus stabilize their water relations, whereas L. decidua behaves “anisohydric” and maintains high transpiration rates.