Sperm quality in male <Emphasis Type="Italic">Barbus barbus</Emphasis> L. fed different diets during the spawning season

Sperm quality of Barbus barbus L. was compared among the three following dietary regimes: Group A, fed 100% commercial diet (Karpico™ containing 33% crude protein and 6% fat), Group B, fed 78% commercial diet and 22% frozen chironomid (Chironomus plumosus) larvae, and Group C, fed 56% commercial diet and 44% frozen chironomid larvae. Concentrations of polyunsaturated fatty acids (PUFAs) in Group A, B, and C were 39.1, 42.0, and 44.6, respectively, as a percentage of total fatty acids. Sperm morphology, volume, concentration and motility, total number of spermatozoa, and osmolality of the seminal plasma were compared during the spawning season. Dietary regime did not influence sperm volume, concentration, or total number of spermatozoa, osmolality of seminal plasma, or the percentage of motile sperm, but significantly affected sperm morphology (except for anterior and posterior parts of the midpiece) and sperm velocity (P < 0.05). Groups B and C showed similar sperm characteristics during the spawning season compared to Group A. Almost all parameters changed either among or within groups during the spawning season, suggesting differences in terms of the optimal time for sperm collection. The best time for sperm collection was March for Group A, but April for Groups B and C, when the osmolality of the seminal plasma measured 289 mOsmol kg⁻¹ and sperm motility was maximal. Spermatogenesis, hydration, and cell decomposition were confirmed as the three major parameters controlling sperm characteristics during the spawning season. The possible correlation between sperm morphology and motility requires further study.     

The possibility of application of agglomerate elastomers (EPP) as media for biological bed in aquaculture

The aim of the study was to determine the possibility of experimental media (agglomerate elastomers EPP) application as biological media bed, which serves the purpose of water purification in recirculating aquaculture systems (RAS). RAS enables mass‐production of fish in small volume of water in a limited area. This involves the possibility of multiple usage of water during culture. However, for that purpose of maintaining proper physico‐chemical parameters, water purification from products of metabolism, especially toxic nitrogen compounds, is required. One of the simplest and most effective ways to achieve it is combining application of two types of water filtration: mechanical and biological. It is needed to study new media for biological bed with proper filling is able to purify water from toxic nitrogen compounds.     

Effect of temperature on growth and survival of maraena whitefish Coregonus maraena (Bloch 1779) larvae in controlled conditions

This 28‐day study investigated the effect of three rearing temperatures, 11, 15 and 19°C, on survival and growth of maraena whitefish fry in a recirculating aquaculture system. Three groups of larvae in three repetitions were reared in recirculating system. Each group comprised 200 larvae. Feeding level was fixed at 500–700 Artemia sp. metanauplii per fish per day. Larvae were fed fresh live brine shrimp at 10 ml/tank every 3 hr. Significantly higher body weight (p = 0.00), total length (p = 0.00), larval yield (p = 0.00) and condition factor (p = 0.00) were obtained at 19°C compared to 15 and 11°C, as well as at 15°C compared to 11°C. Significantly higher survival (p = 0.00) was observed in larvae reared at 11 and 15°C compare to 19°C and no significant differences were observed between 11°C compared to 15°C. No significant differences in size heterogeneity among treatments were found (p = 0.46). In larviculture, the optimal assessed temperature for growth of maraena whitefish was 19°C, with highest survival observed at 11°C, at the end of this 28 days trial. The findings in this study apply to the particular study location and may not be applicable more broadly.     

Novel technique for definite blastomere inhibition and distribution of maternal RNA in sterlet Acipenser ruthenus embryo

Fisheries Science - The cleavage pattern of a vertebrate’s embryo is either holoblastic (complete) or meroblastic (partial). Sturgeon and other basal bony fishes represent a transition of the...     

Neuropeptides isotocin and arginine vasotocin in urophysis of three fish species

In this study, for the first time, both neuropeptides isotocin (IT) and arginine vasotocin (AVT) have been identified and measured in urophysis, the neurohaemal organ of the caudal neurosecretory system of teleost fish. So far, AVT, but not IT, was quantified by radioimmunoassay (RIA) in urophysis of several fish species. We have used high-performance liquid chromatographic assay with fluorescence detection (HPLC-FL) preceded by solid-phase extraction (SPE) and liquid chromatography-electrospray ionization triple-quadrupole tandem mass spectrometry (LC-ESI MS/MS) technique to determine both neuropeptides in urophysis of three fish species. The efficiency of peptide’s SPE extraction was 79–85 %. In HPLC-FL method, the limits of detection (LOD) and quantification (LOQ) were estimated as 1.0 and 3.4 pmol/mL for IT and 0.25 and 2.20 pmol/mL for AVT. In LC–MS/MS method, LOD and LOQ were estimated as 0.4 and 1.2 pmol/mL for IT and 0.06 and 0.2 pmol/mL for AVT. The chromatographic methods are good alternative for RIA, because enable to measure both nonapeptides simultaneously in one sample. In round goby (Neogobius melanostomus), three-spined stickleback (Gasterosteus aculeatus) and sea bream (Sparus aurata), urophysial IT concentrations ranged between 0.056 and 0.678 pmol/mg tissue and AVT concentrations ranged between 0.0008 (or even below detection threshold) and 0.084 pmol/mg tissue.     

The antioxidant system of sterlet seminal fluid in testes and Wolffian ducts

Oxidative stress is a possible source of spermatozoa function deterioration. Seminal fluid (SF) protects spermatozoa against reactive oxygen species (ROS) attack during development in testes and transit through the reproductive tract. Spermatozoa curvilinear velocity and percent of motile cells as well as changes in thiobarbituric acid-reactive substance (TBARS) content, superoxide dismutase, and catalase activity, and uric acid concentration in SF were evaluated in sterlet sperm collected from testes 24 h after hormone induction of spermiation and from Wolffian ducts at 12, 24, 36, and 60 h after hormone injection (HI). While testicular spermatozoa motility was not initiated in activating medium, Wolffian duct sperm showed low motility at 12 h, significant increase at 24 and 36 h, and decrease at 60 h. Testicular SF was characterized by the highest level of TBARS and activity of studied enzymes compared with SF from Wolffian duct sperm at 24 h post-HI. In fluid from Wolffian duct sperm, a significant increase in TBARS content was shown at 36–60 h post-HI. In contrast to testicular SF, in SF from Wolffian duct sperm, this increase was not counterbalanced by changes in the studied variables of antioxidant system. This may be the source of the observed decrease in spermatozoa motility parameters 60 h post-HI. The results may confirm a dual role of ROS in fish sperm physiology. The data with respect to decrease in sturgeon spermatozoa motility parameters at 60 h post-HI should be taken into account in artificial sturgeon propagation.     

Motility parameters of perch spermatozoa (Perca fluviatilis L.) with cryoprotectors addition

The addition of cryoprotectants during the freezing of semen in liquid nitrogen protects spermatozoa from the negative influence of freezing. Every species needs an appropriate cryoprotectant that has to be experimentally selected. Semen obtained from five perches was diluted with the Kobayashi buffer solution at 1:9 ratio. To determine the influence of cryoprotectants on spermatozoa motility parameters, the same type of buffer solution was applied with the addition of methanol, dimethyl sulfoxide (DMSO) and dimethylacetamide (DMA) using the concentration of 10, 5, 2.5 %, respectively, glycerol (15; 7.5 %), sucrose and trehalose (0.45; 0.225; 0.113 M). After the preparation of such tests, parameters of spermatozoa motility were measured, using the CASA system (Image House CRISMAS Company Ltd.). Among used cryoprotectants, methanol did not cause any effect on the sperm motility parameters. The lowest percentage concentrations of DMA, DMSO, glycerol, sucrose and trehalose did not significantly influence the percentage of motile spermatozoa. Higher concentrations of these compounds considerably lowered all motility parameters. As for glycerol and saccharides, their addition resulted in the lowering of the spermatozoa motility possibly due to a higher viscosity of the solution. However, DMA and DMSO were most probably toxic to perch sperm cells. The obtained results indicate that the best cryoprotectant to be used with perch spermatozoa is methanol.     

Early development and allometric growth patterns in burbot Lota lota L.

This study analyzed the morphological development and allometric growth patterns of Lota lota L. (burbot) larvae reared under controlled laboratory conditions. From hatching to day 50, twenty larvae were sampled each [between 1 and 14 days post-hatch (DPH)] or every second day (between 14 and 50 DPH) and measured under a stereoscopic microscope using analytic software. Based on the external morphology, the different stages during early development of burbot were identified: yolk sac larva 0–8 DPH [3.92–4.37 mm total length (TL)]; preflexion larva 9–26 DPH (4.57–12.06 mm TL); flexion larva (between notochord degradation and its replacement with rays) 28–34 DPH (14.00–16.34 mm TL) and postflexion larva/juvenile 36–50 DPH (18.20–29.27 mm TL). Allometric growth patterns of some parameters (e.g., total length, head length, body length, tail length, head depth, body depth, eye diameter) were modeled by a power function and described by the growth coefficient. Organogenesis and changes of body proportions in burbot larvae were more rapid and complex during the yolk sac and preflexion phase of development as larvae developed most of their sensorial, feeding, respiratory and swimming systems and after notochord flexion, when most morphological changes were related to the progressive transformation from pelagic larva to demersal larva/juvenile.     

Effects of Serpentinite Fertilization with N,P, and K Fertilizers on Soil Properties and Needle Chemistry

The aim of the present research was to study the long-term effect of serpentinite fertilization with additional nitrogen, phosphorous, and potassium fertilizers on some physicochemical properties and the enzyme activity of acidic soils and needle chemistry in stands of Norway spruce (Picea abies (L.) Karst.). Experimental plots were located in spruce stands in the middle forest zone (900–950 m) on two nappes of the Carpathian flysch: Magura and Silesian. Serpentinite was introduced in autumn 2008 on all plots while the other fertilizers in spring 2009. The effect of fertilization was visible mainly in the humus horizon. No significant changes were found in the deeper mineral soil. The acidity and Al toxicity in the surface horizon were ameliorated through serpentinite fertilization. Five years after fertilization, no significant difference in the fertilization treatments was noted in the chemistry of the spruce needles.     

Comparison of Iodide and Iodate Accumulation and Volatilization by Filamentous Fungi during Static Cultivation

Five common fungal strains, Cladosporium cladosporioides, Aspergillus clavatus, Penicillium citrinum, Fusarium oxysporum, and Alternaria alternata, were cultivated in presence of iodide and iodate to evaluate their efficiency in iodine biovolatilization and bioaccumulation. Our results suggest that iodide and iodate bioaccumulation by microscopic filamentous fungi is similar although the biological transformation into volatile iodine compounds is driven by various pathways resulting in higher volatilization efficiency of iodate. Thus, the mobilization of iodate by filamentous fungi is superior to iodide mobilization. Our paper is also the first to compare the iodide and iodate volatilization efficiency by microorganisms. Our results highlight the significant role of filamentous fungi in biogeochemistry of iodine, especially in formation of environmentally reactive volatile forms that may contribute to ozone layer destruction.