[Periods for growth and quality improvement of fish in context of animal welfare compliant management of commercial fish ponds--a literature review].

In Germany, management of commercial fish ponds requires consideration of animal welfare legislation. In particular, it is forbidden to immediately catch fish that have recently been stocked into put-and-take fishponds. Rather, after stocking is completed, a short-term fishing ban period needs to be adhered to that allows the fishes the opportunity to grow and/or significantly improve in overall quality.

Intestinal nematodes affect selenium bioaccumulation, oxidative stress biomarkers, and health parameters in juvenile rainbow trout (Oncorhynchus mykiss).

In environmental studies, parasites are often seen as a product of enhanced host susceptibility due to exposure to one or several stressors, whereas potential consequences of infections on host responses are often overlooked. Therefore, the present study focused on effects of parasitism on bioaccumulation of selenium (Se) in rainbow trout (Oncorhynchus mykiss). Joint effects of biological (parasite) and chemical (Se) stressors on biomarkers of oxidative stress (glutathione-S-transferase (GST), superoxide dismutase (SOD)), and fish health (condition factor (K), hepatosomatic index (HSI), gross energy) were also examined.

Chemical contaminants and parasites: assessment of human health risks associated with consumption of whitefish (Coregonus clupeaformis) from two boreal lakes in northern Saskatchewan, Canada.

In Canada there is increasing concern about potential effects of industrial activities on wildlife and human health. In an interdisciplinary study concentrations of inorganic (metals, metalloids) and organic (PCBs, organochlorine pesticides) contaminants, and parasitic infections of lake whitefish (Coregonus clupeaformis) from Montreal and Reindeer lakes, Saskatchewan, were investigated to assess human health risk related to fish consumption. In both lakes contamination of fish with chemical substances and compounds, respectively, were very low and often close to detection limits.

Attenuation of the cortisol response to stress in female rainbow trout chronically exposed to dietary selenomethionine.

Selenomethionine (Se-Met) is the major dietary form of selenium (Se). While Se is a required nutrient, it can also influence the physiological stress response because it stimulates greater concentrations of cortisol in blood plasma of exposed fish. However, little is known about the effects of exposure to Se on the ability to cope with a secondary stressor.

Combined effects of parasites and contaminants on animal health: parasites do matter.

The cumulative effects of multiple stressors are becoming a priority concern for ecotoxicologists, ecologists and conservation biologists working to understand threats to ecosystems and species. In that context, parasites and pathogens are increasingly a focus of attention. Parasites interact with natural and anthropogenic stressors to increase mortality and reduce animal health in myriad ways in a wide spectrum of host and parasite taxa.

Humic substances. Part 1: Dissolved humic substances (HS) in aquaculture and ornamental fish breeding.

Goals, Scope And Background: Changing environmental conditions and handling stress are well known to cause chronic or acute stress situations in fish with subsequent infections. These requires a therapy by means of antibiotics and chemicals. In contrast to the huge number of pathogens, only a few substances are permitted for application as therapeutics in German aquaculture.

Infectivity of Ornithodiplostomum ptychocheilus and Posthodiplostomum minimum (Trematoda: Diplostomidae) cercariae following exposure to cadmium.

The effect of cadmium (Cd) exposure on infectivity of cercariae of 2 trematode species (Ornithodiplostomum ptychocheilus and Posthodiplostomum minimum) to their second intermediate fish host was evaluated. Individual fathead minnows (Pimephales promelas) were exposed to cercariae that had been treated with Cd solutions at concentrations of 0, 2, 20, or 200 microg/L for 2 hr. Two weeks later, the numbers of encysted metacercariae in the brain (O.

Cadmium accumulation in zebrafish (Danio rerio) eggs is modulated by dissolved organic matter (DOM).

Experiments were conducted to investigate factors influencing the accumulation of cadmium (Cd(2+)) into zebrafish (Danio rerio) eggs. The accumulation of (109)Cd was affected by: (1) concentration, (2) time, (3) presence of dissolved organic material (DOM), (4) different origin of DOM and (5) different parts of fish eggs. Over a 5-h exposure, zebrafish eggs showed a steady increase in Cd-accumulation.

Free-living endohelminth stages: at the mercy of environmental conditions.

During their free-living phases, endohelminths are directly exposed to environmental conditions in their respective macrohabitats. Both natural environmental factors and pollutants released into the environment through anthropogenic activities can influence the success of the free-living stages. This overview examines the effects of natural variables and pollutants on two specific properties (survival and infectivity) of free-living stages of endohelminths, mainly trematodes, while fully recognizing that other parasitic life history stages in addition to the hosts can also be affected.