Brown trout in Oder estuary tributaries: genetic structure, stocking, and admixture.

Several rivers that are tributaries of the Oder estuary are inhabited by Salmo trutta L, the most important of which are Ina, Gowienica, and Wolczenica. Both forms of the species, sea trout and resident brown trout, are present. All rivers are traditionally stocked with either sea trout from the neighboring Pomeranian river Rega basin or resident brown trout from various locations. To examine populations in these rivers in terms of genetic structure, genetic diversity, and origin, they were analyzed using 13 microsatellite loci. Relatedness was also assessed for fish stocked in the same year. The obtained genotypes were compared with breeding stocks used for stocking in Poland. The analyses revealed a significant genetic distance between adult individuals from Ina and Rega Rivers and fish caught during electrofishing. Strong kinship relationships were identified in the sampled areas, with high proportions of fish originating from stocking and their dominance in numbers over wild juveniles, primarily in smaller tributaries. Additionally, clear separation in the origin of stocked individuals was observed. Adult trout from Ina and Rega are genetically closer to northern brown trout lineages, providing crucial information for the management and biodiversity conservation of Polish Salmo trutta populations.

Parentage-based tagging and parentage analyses of stocked sea trout in Vistula River commercial catches.

The longest Baltic River, the Vistula, historically hosted numerous sea trout populations. However, dam construction in the twentieth century drastically reduced the spawning migration rate. Reduced natural reproduction has resulted in a population collapse and, consequentially, a substantial reduction in catches. In response, like other Baltic countries, Poland has initiated an intensive stocking program, mainly involving smolt. Initially, stocking was conducted primarily with offspring of sea trout caught during spawning migration. Currently, due to difficulties in obtaining fish, most stocking involves fish from breeding stocks. Therefore, determining the proportion of fish derived from stocking has become an important issue. Experiments based on traditional tagging did not provide sufficient material for analysis; hence, we decided to use genetic methods based on analysis of relatedness. In this study, we performed parentage-based tagging and an analysis of the origins of parent animals used for artificial spawning in 2013, and offspring returning to the Vistula in subsequent years. We based the analysis on three different algorithms and compared the results, showing that the presented methods were effective for estimating mass stocking success. The study also indicated that a certain level of natural reproduction in the Vistula continues to occur. The proportion of sea trout from spawning in 2013 in Vistula sea trout catches from 2017 to 2018 was approximately 30%.

Evidence of unidirectional gene flow in a fragmented population of Salmo trutta L.

Selection, genetic drift, and gene flow affect genetic variation within populations and genetic differences among populations. Both drift and selection tend to decrease variation within populations and increase differences among populations, whereas gene flow increases variation within populations but leads to populations being related. In brown trout (Salmo trutta L.), the most important factor in population fragmentation is disrupted river-segment connectivity. The main goal of the study was to use genetic analysis to estimate the level of gene flow among resident and migratory brown trout in potential hybridization areas located downstream of impassable barriers in one river basin in the southern Baltic Sea region. First, spawning redds were counted in the upper river basin downstream of impassable barriers. Next, samples were collected from juveniles in spawning areas located downstream of barriers and from adults downstream and upstream of barriers. Subsequently, genetic analysis was performed using a panel of 13 microsatellite loci and the Salmo trutta 5 K SNP microarray. The genetic differentiation estimated between the resident form sampled upstream of the barriers and the anadromous specimens downstream of the barriers was high and significant. Analysis revealed that gene flow occurred between the two forms in the hybridization zone investigated and that isolated resident specimens shared spawning grounds with sea trout downstream of the barriers. The brown trout population from the river system investigated was slightly, internally diversified in the area accessible to migration. Simultaneously, the isolated part of the population was very different from that in the rest of the basin. The spawning areas of the anadromous form located downstream of the barriers were in a hybridization zone and gene flow was confirmed to be unidirectional. Although they constituted a small percentage, the genotypes typical upstream of the barriers were admixed downstream of them. The lack of genotypes noted upstream of the barriers among adult anadromous individuals might indicate that migrants of upstream origin and hybrids preferred residency.

Genetic structure of important resident brown trout breeding lines in Poland.

The history of brown trout Salmo trutta L. stocking has long tradition in the European Union and other countries. Hundreds of hatchery facilities on continent have artificial broodstocks used for enhancement of neighbouring and also geographically far river basins. These practices have substantial effect on wild brown trout populations. To illuminate this phenomenon, eleven hatchery stocks and wild populations from northern Poland and Carpathian region were analysed using 13 microsatellite markers. Obtained results revealed high genetic diversity between studied stocks and clear differentiation between northern and southern populations and hybridization between these two major clads. As a recommendation, the principle of treating regions as metapopulations should be applied, which, in the case of Poland, means using the division of the northern and southern genetic lines that were revealed in the present study.

Elaidic acid and vaccenic acid in the plasma of pregnant women and umbilical blood plasma.

INTRODUCTION: The studies suggest that trans fatty acids are the most harmful type of fatty acids, and their ingestion leads to an increase in oxidative stress, changes in the plasma levels of LDL cholesterol, and a reduction in n-6 and n-3 fatty acids utilization. The objective of this study was to determine the concentration profiles of elaidic and vaccenic acids in maternal blood plasma in the perinatal period, and in the plasma of blood collected from the umbilical vein. The article deals with the issue of the correlation between the levels of trans-unsaturated fatty acids in maternal and neonatal blood, which could suggest the transplacental transport of these acids. The potential correlations between the levels of trans-unsaturated fatty acids in maternal and umbilical blood and birth weight and body length in neonates was also verified. MATERIAL AND METHODS: The study group comprised 53 pregnant patients of the Clinic of Obstetrics and Perinatology of the Pomeranian Medical University in Szczecin, aged 18-39 years, together with their newborn babies. Elaidic and vaccenic acid levels were determined in maternal and umbilical plasma. Fatty acid methyl esters were injected onto the capillary column of the Agilent 6890M gas chromatography system integrated with an autosampler. The content of individual fatty acids was determined from the reference curves and expressed in mg/mL. RESULTS: The lowest levels of both acids were observed in umbilical blood plasma. The level of elaidic acid was 0.0019 mg/mL ± 0.0013 mg/mL, while the level of vaccenic acid was 0.0007 mg/mL ± 0.0011 mg/mL. A statistically significant negative correlation was observed between maternal vaccenic acid levels and umbilical vaccenic acid levels. CONCLUSIONS: The presence of trans-unsaturated fatty acids (elaidic acid and vaccenic acid) in umbilical plasma is evidence of the transplacental transport of these acids. The significantly higher levels of elaidic acid compared to vaccenic acid in umbilical plasma suggests that vaccenic acid is more extensively metabolized in placenta. The levels of trans-unsaturated fatty acids had no effect on birth weight and body length in neonates.

[Trans fatty acids (elaidic and vaccenic) in the human milk]. / Wystepowanie nienasyconych kwasów tluszczowych typu trans (elaidynowego i wakcenowego) w mieku kobiecym.

INTRODUCTION: The structure of trans unsaturated fatty acids (TFAs) includes at least one double bond with a trans configuration. Numerous studies have shown that TFAs influence negative changes in blood lipid profile, may initiate or accelerate the course of many inflammatory diseases, and reduce n-6 and n-3 fatty acids' utilization. Their presence in tissues and systemic fluids is mainly the result of ingestion of TFA-containing foods. The objective of this study was to determine the concentration profiles of elaidic and vaccenic acids in human milk, and the existence of potential correlations between the levels of trans-unsaturated fatty acids and long chain polyunsaturated fatty acids. MATERIALS AND METHODS: The study group consisted of 53 lactating women, aged 18-39 years, 5-6 weeks after delivery. Elaidic and vaccenic acid levels were determined in human milk. Fatty acid methyl esters were injected onto the capillary column of an Agilent 6890M gas chromatography system integrated with an autosampler. Geometrical and positional isomers of fatty acids were identified by comparing their retention times with those of the fatty acid standards from Sigma-Aldrich. The content of individual fatty acids was determined from the reference curves and expressed in mg/mL. RESULTS: The level of elaidic acid was 0.2572 ± 0.1811 mg/mL, and the level of vaccenic acid was 0.2736 ± 0.1852 mg/mL. No negative correlations between the levels of the analyzed TFAs and PUFAs were observed in human milk. CONCLUSIONS: The levels of elaidic and vaccenic acid were similar and had no negative influence on the levels of arachidonic acid and docosahexaenoic acid.

Method improvement: released cecal ligation-septic shock model.

A new released cecal ligation (RCL) technique of septic shock induction in rats is presented. It is relatively not complicated, fast, not expensive, and it mimics the human pathology. Presented procedure seems to be a useful alternative for the cecal ligation alone or cecal ligation and puncture to induce experimental septic shock in small laboratory animals.