Comparative analysis of using cereal grains and compound feed in semi-intensive common carp pond production

The semi-intensive system of carp farming is dominant in inland aquaculture. Although it appears to be simple, this system has a whole range of options, from those based on traditional rearing methods with use of plants from the region where the fish are reared to production based on the use of high-quality concentrated feeds. In this paper, we conduct a comparative analysis of the effect of using cereal grains as opposed to compound feed (pelleted and extruded) on the quantity of fish produced, flesh quality, histological changes in the digestive tract, water quality, and structure of the biocoenosis in the pond ecosystem. When the fish are fed cereal grains, production ranges from 500 to 1500 kg/ha, while using compound feed gives production that is twice as great. The proportions of protein and water are higher and that of lipids lower in flesh of common carp reared on compound feed in relation to fish fed cereal grains. Use of extruded feed gives better content of n-3 polyunsaturated fatty acids and a better n-3/n-6 ratio than when pelleted feed and cereal grains are used. Comparison of water quality in carp ponds under conditions of using various types of feed indicates that there are no significant differences. Although it was expected that feed with a higher percentage of proteins would cause disturbances in the aquatic ecosystem, their continual incorporation into the cycling of matter in the water contributes to maintenance of ecological equilibrium and even indirectly promotes growth of the common carp.     

Estimation of quantitative genetic parameters for grain yield and quality in winter wheat under high and low nitrogen fertilization

The main question connected with developing wheat cultivars adapted to low nitrogen (N) is whether separate breeding programs for low and high input conditions are necessary. Nineteen wheat cultivars were grown over three years in Croatia in a total of eight environments at high N and low N in order to determine the effect of two N levels on means, variances and heritability of grain yield and bread-making quality and to assess the relative efficiency of indirect selection under high N in improving trait means under low N. Means of grain yield and grain protein content decreased under low N 10 and 13 %, respectively compared to the high N, whereas higher reductions of means due to lower fertilization were observed for grain N yield (21 %), wet gluten content (20 %), Zeleny sedimentation value (27 %) and for most rheological parameters, whose mean values were reduced from 20 % to as much as 57 %. Heritabilities for grain yield and grain N yield at high N were 0.82 and 0.76, respectively, and 0.77 and 0.43 at low N. Heritability for dough development time, stability and resistance also tended to be higher at high N than at low N due to a decrease in genetic variance and an increase in error variance at low N. The genetic correlation coefficients between high and low N were higher than 0.90 and the efficiency of indirect selection under high N for performance under low N was near 1.0 for grain yield and for most bread-making quality traits.     

Degradation Kinetics of an Aged Hydrocarbon-Contaminated Soil

PM2.5 and PM10 samples were collected in the urban atmosphere of Elche (southeastern Spain) between December 2004 and November 2005. The samples were analyzed for mass and water-soluble inorganic ions (Na⁺, ${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$ , K⁺, Ca²⁺, Mg²⁺, Cl^?, ${\text{NO}}^{{\text{ - }}}_{{\text{3}}}$ and ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ ) with the aim of investigating the influence of the climatic and geographic features of a coastal semiarid area on the contribution of these species to PM levels. Secondary inorganic ions ( ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ , ${\text{NO}}^{{\text{ - }}}_{{\text{3}}}$ , ${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$ ) were the major components in the fine fraction (PM2.5), accounting for 40% of the total mass. The relationship between non-marine ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ and ${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$ indicated that fine sulfate particles were completely neutralized by ammonium. In the coarse fraction (PM10–2.5), nitrate (as NaNO₃ and Ca(NO₃)₂), together with crustal (CaCO₃) and marine species (NaCl) accounted for almost 50% of the total mass. Fine sulfate and coarse nitrate showed summer maximums. In contrast, the concentrations of fine ${\text{NO}}^{{\text{ - }}}_{{\text{3}}}$ were lowest in the warm period. Ammonium presented both winter and summer maximums. The levels of marine ions, except for coarse Cl^?, were highest in summer when the dominant wind flow is from the sea. No significant seasonal variations were observed for coarse Ca²⁺ and ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ . The concentrations of all inorganic ions increased during Saharan dust events, in particular, fine ${\text{NH}}^{{\text{ + }}}_{{\text{4}}}$ and ${\text{SO}}^{{{\text{2 - }}}}_{{\text{4}}}$ and coarse $NO_3^ - $ . Coarse calcium was proved not to be a good tracer for this type of episode in our region since the average levels of this cation are elevated and the relative increase in its concentrations during African events was not as high as expected.     

Free radical scavenging activity of three Equisetum species from Fruska gora mountain

The scavenger activities of Equisetum arvense, Equisetum ramosissimum and Equisetum telmateia aboveground parts phosphate buffer (pH 7) extracts were evaluated using three different methods: DPPH assay, ESR and NO radical inhibition assay. Total reducing power was determined by FRAP assay. The E. telmateia extract demonstrated the most relevant scavenger and antioxidant properties. ESR signal of DMPO-OH radical adducts in the presence of E. telmateia phosphate buffer (pH 7) extract was reduced to 98.9% which indicated that E. telmateia could be a useful source of antioxidants with huge scavenger ability.     

Effect of supplemental feed type on water quality,plankton and benthos availability and carp (Cyprinus carpio L.) growth in semi‐intensive monoculture ponds

A four‐and‐a‐half months study was conducted in nine earthen ponds to evaluate the addition of different supplemental feeds as a management tool for enhancing natural food availability and common carp growth, while maintaining optimal water quality in the semi‐intensive system. Three supplemental feeds were used: commercial extruded and pelleted feed with 25% protein and 7% fat and cereals. The type of supplemental feed did not influence water quality, except hardness, but significantly affected abundance of cyanobacteria, natural food availability and common carp growth. The use of pelleted feed was related to the lowest abundance of cyanobacteria in the ponds. For the two groups of large zooplankton, Cladocera and Copepoda, abundances were higher in the ponds with pelleted feed compared with the ponds where cereals and extruded feed were used. The abundance of benthic macroinvertebrates in the treatment with pelleted feed was three times higher than in the other two treatments. The results of this study indicate that pelleted feed can help farmers not only as a source of nutrients for carp growth but also indirectly as a management tool for maintaining ecological stability and control of cyanobacterial bloom in ponds.     

Genetic diversity within sea trout population from an intensively stocked southern Baltic river,based on microsatellite DNA analysis

Sea trout, Salmo trutta L., populations in the Slupia River basin have been affected by mass stocking with smolts and fry. This work is focused on a small‐scale differentiation in sea trout populations from one basin with a strong emphasis on the relationship between wild and hatchery origin fish. A total of 216 sea trout were genotyped at 10 microsatellite loci. Global F_ST obtained by amova was low at 0.0165. Pairwise F_ST were significant for all tests except wild and stocked adults. The highest pairwise difference was found between the hatchery sample and Kwacza (F_ST = 0.038). Analysis of the genetic structure revealed micro‐geographical differentiation with four subpopulations. The quality of the artificial spawning was found not to be adequate with a high risk of adverse effects to the whole population. All future stocking actions in the basin should consider the existing population structures.