The impact of carp pond management upon macrozoobenthos assemblages in recipient pond canals

Impact of carp pond management upon macrozoobenthos assemblages was studied in inlet and outlet carp pond canals in South Moravia (Czech Republic). Four ponds (two eutrophic and two hypertrophic ones) with different types of fish farming management and intensification measures were selected for the evaluation of the impact of inlet water quality, discharge rate and pond stocking management upon the outlet water quality determinants based on macrozoobenthos evaluation during April–September 2009. Five inlet and four outlet canals were sampled by “kick–sampling” approach and also by using the artificial substrates. The pattern of water quality changes after the flow through the pond was predominantly influenced by inlet water quality. In ponds supplied with worsened inflow water quality with the saprobic index (SI) according to macrozoobenthos corresponding to alpha-mesosaprobity (SI 2.82–2.89), the outflow water quality was significantly improved by approximately half of the saprobic degree on SI 2.38–2.42. On the contrary, the inflow water quality corresponding to beta-mesosaprobity (SI, 2.32) was significantly (p < 0.01) deteriorated to alpha-mesosaprobity in the pond outflow. Macrozoobenthos diversity and the number of taxa reflected the flow through the pond identically with saprobic determinants. In ponds with poor inflow water quality, the number of macrozoobenthos taxa and its diversity increased in the outlet canals, and vice versa, in ponds with good-quality inflow water, the number of taxa and macrozoobenthos diversity decreased in outlet canals.     

Brief communication: rapid elimination of egg stickiness using sodium hypochlorite in wels catfish Silurus glanis

Fish Physiology and Biochemistry - The wels catfish Silurus glanis is valuable fish for aquaculture. Its production relies mainly on artificial reproduction. One of the crucial steps determining...     

Effect of delipidant agents during in vitro culture on the development,lipid content,gene expression and cryotolerance of bovine embryos

In vitro produced embryos are still sensitive to the freezing process which can be explained, in part, by the high-lipid accumulation that characterizes these embryos. Therefore, we aimed to evaluate the effect of delipidating agents, L-carnitine and the trans-10 cis-12 conjugated linoleic acid (CLA) isomer, on blastocyst development, lipid content, gene expression and cryotolerance when added to embryo culture media. Embryos were cultured in four different media: T1: control (n = 616), synthetic oviduct fluid (SOF) media with 5% foetal bovine serum (FBS); T2: L-carnitine (n = 648), SOF medium with 5% FBS and 0.6 mg/ml of L-carnitine; T3: CLA (n = 627), SOF medium with 5% FBS and 100 μM trans-10 cis-12 CLA; and T4: L-carnitine + CLA: (n = 597), SOF medium with 5% FBS plus 0.6 mg/ml L-carnitine and 100 μM trans-10 cis-12 CLA. Supplementation of culture medium with either or both delipidating agents reduced (p < .05) blastocyst rate on D7 (T1 = 49 ± 3.5; T2 = 39 ± 3.0; T3 = 42 ± 3.9 and T4 = 39 ± 3.9), but did not affected gene expression (p > .05). Although embryos cultured in the presence of L-carnitine contained fewer (p < .05) lipid droplets than the control embryos, they showed a lower re-expansion rate 24 hr post-thaw than those (p < .05). In conclusion, although L-carnitine reduced the amount of lipids in cultured embryos, the use of L-carnitine and CLA during in vitro culture was not able to improve the embryo production and the response to cryopreservation.     

The effects of metribuzin on early life stages of common carp (Cyprinus carpio)

Metribuzin belongs to the triazine group of herbicides, which are frequently used in agriculture. The aim of this study was to assess the impact of metribuzin on growth and development of early life stages of fish. Subchronic toxic effects of metribuzin at concentrations of 0.9, 4, 14, and 32 mg/L on embryos and larvae of common carp (Cyprinus carpio) were investigated during a 30 day toxicity test under experimental conditions. Exposure to metribuzin at 32 mg/L was associated with increased mortality. Negative effects on total body length, weight, and inhibition of specific growth rate were induced by all experimental concentrations. Length and weight parameters were the most sensitive. The negative impact of metribuzin was observed in the highest tested concentration beginning on day 6 of exposure. Retardation of early ontogeny was associated with concentrations ?4 mg/L. Histological examination revealed changes in liver and caudal kidney after 30 days exposure to 32 mg/L. Based on growth parameters, development, and histological examination, the Lowest Observed Effect Concentration (LOEC) value was 0.9 mg/L.     

Simplified performance assessment methodology for addressing soil quality of nature-based solutions

Journal of Soils and Sediments - In urban areas, soil functions are deeply impacted by all human activities, e.g., water infiltration, carbon storage, and chemical substances degradation potential....     

Recovery of Trichinella Spiralis Larvae From Frozen Muscle Samples

Demonstration of Trichinella spiralis in suspensions of digested muscle tissue has until now mainly been based on methods utilizing the coiling and/or the motility of the living larvae. Considering this, Jackson (1977) estimated that, compared to the number observed by examination of corresponding unfrozen samples, 78 % of larvae in frozen samples would be lost, when an ordinary pepsin-HCl digestion technique was used.     

A New Technique for Demonstration of Trichinella Spiralis Larvae in Suspensions of Digested Muscle Tissue

Up to now, a sedimentation technique has been used for demonstration of Trichinella spiralis larvae released by artificial digestion (Henriksen 1973, Skovgaard 1975, Thomsen 1976, 1977, and others).     

The structure of a pH-sensing mycobacterial adenylyl cyclase holoenzyme

Class III adenylyl cyclases contain catalytic and regulatory domains, yet structural insight into their interactions is missing. We show that the mycobacterial adenylyl cyclase Rv1264 is rendered a pH sensor by its N-terminal domain. In the structure of the inhibited state, catalytic and regulatory domains share a large interface involving catalytic residues. In the structure of the active state, the two catalytic domains rotate by 55 degrees to form two catalytic sites at their interface. Two alpha helices serve as molecular switches. Mutagenesis is consistent with a regulatory role of the structural transition, and we suggest that the transition is regulated by pH.     

System approach to drainage,irrigation and soil conservation related to water quality problems

The system approach and combination of simulation and optimization models to the problems of water quality in public water supply basins influenced by agricultural activities, drainage, irrigation and soil conservation are presented. The methodological aspects of the problem are analysed.