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With the growing importance of aquaculture worldwide, characterization of the microbiota of high-value aquaculture species and identification of their shifts induced by changes in fish physiology or nutrition is of special interest. Here we report the first 16S rRNA gene metabarcoding survey of the mid-intestinal bacteria of Chinook salmon (Oncorhynchus tshawytscha), an economically important aquacultured species. The microbiota of 30 farmed Chinook salmon from a single cohort was surveyed using metabarcode profiling of the V3-V4 hypervariable region of the bacterial 16S rRNA gene. Seawater, feed and mid-intestinal samples and controls were sequenced in quadruplicate to assess both biological and technical variation in the microbial profiles. Over 1000 operational taxonomic units were identified within the cohort, providing a first glimpse into the mid-intestinal microbiota of farmed Chinook salmon. The taxonomic distribution of the salmon microbiota was reasonably stable, with around two thirds of individuals dominated by members of the family Vibrionaceae. We anticipate that the workflow presented in this paper could be applied in other aquacultured fish species to capture variation or dysbiosis occurring as a result of changes in feed, health or environmental conditions.

The development and improvement of the monitoring system of rivers according to the requirements of the Water Framework Directive (WFD) is essential for all European states because assigning a wrong ecological status class (misclassification) to a water body can have significant economic consequences. In order to point out some of the key issues of WFD implementation in Serbia, we conducted a one-year study of the composition and abundance of diatoms in the phytobenthos in two streams, the Lasovačka and Lenovačka, in eastern Serbia. The physicochemical quality elements were also used in the assessment of their ecological status. The diatom community exhibited a higher species richness in the Lasovačka (88 taxa) than in the Lenovačka stream (63 taxa). Such a detailed study enabled us to record some of the rare taxa, e.g. Caloneis budensis in the Lasovačka, which was the first finding of this species in Serbia. The Lasovačka and Lenovačka streams were downgraded to moderate and poor ecological status, respectively, because of the high nitrogen load. Since the monitoring results based on the diatom indices resulted in the assignment of two streams to a good ecological status, the possible reason for the mismatch between the biological and physicochemical quality elements could be due to the lack of analysis of benthic invertebrate fauna or the application of diatom indices that are insufficiently sensitive to the specific environmental pressure. The results of this study show that conducting a comprehensive ecological investigation of rivers within the framework of the WFD in Serbia is urgently needed. [Project of the Serbian Ministry of Education, Science and Technological Development, Grant no. OI176018 and Grant no. OI172001]

The aim of this paper was to explore hairiness of the middle phalanges on both hands of Serbian high school students. The total sample comprised 425 pupils in the town of Niš of Serbian nationality, aged 15-19 years. Hairiness on the middle phalanges of second, third, fourth and fifth fingers was detected by inspection with a magnifying glass. The results showed that hairiness was more frequent on the fifth finger of boys. The investigation of the hairiness on the middle phalanges of both hands in the region of Niš may be, in comparison with anthropological investigations of other regions, important in the investigation of the genetic cause of the hairiness on the middle phalanges. .