5 research outputs found
The effects of aquaculture activities on species composition and diversity of native freshwater fish populations
Get PDFThe rapid development of the aquaculture industry in recent years and the increase in the intensity of production has raised questions regarding potential environmental impacts. Understanding intra- and interspecific relationships between native and cultured species is important for sustainable use of natural resources. This study investigated the spatial and temporal effects of a fish farm constructed next to a river on the relative abundance and diversity of natural fish populations. Sampling was conducted at three stations, upstream and down stream from a trout farm and at a control site, on Kocabas stream in Çanakkale (Turkey) monthly between August 2015 and July 2016. There was no significant difference among the three stations in fish diversity. However, a remarkable seasonal and spatial variation in the composition and relative proportion of the indigenous fish assemblage were observed among the three stations. In conclusion, the fish farm might have influenced species composition and relative abundances particularly at the downstream station
Evaluation of oregano (Origanum vulgare) essential oil supplementation on growth performance, digestive enzymes, intestinal histomorphology and gut microbiota of Black Sea salmon, Salmo labrax
Get PDFThis study aimed to determine the effect of dietary oregano (Origanum vulgare) essential oil (EO) on the growth performance, digestive enzyme activity, intestinal histomorphology, and intestinal microbiota of the Black Sea salmon juvenile (Salmo labrax). Fish were fed diets different levels of oregano EO such as 50, 100, 200, and 400 mg kg-1. For this purpose, a total of 675 fish were distributed randomly in triplicate into 5 experiment groups in 15 experiment tanks. Fish with average initial weights of 3.52±0.01 g were fed by hand at 3% of live weight for 90 days. At the end of the study, feeding with oregano EO supplementation did not significantly affect the growth performance of fish. Except for pepsin, there were no significant differences in the activity of digestive enzymes among the control and oregano EO groups. Besides, oregano EO at the doses of 50 or 400 mg kg-1 may have the potential to increase the surface area required for digestion by increasing intestinal villi length. Moreover, all doses of oregano EO showed antimicrobial properties by decreasing the count of lactic acid bacteria in the intestine. Supplementation with 100 and 200 mg kg-1 oregano EO in diets decreased the total coliform, Escherichia coli and lactic acid bacteria counts when compared to the control group. The results showed that oregano EO may positively affect digestion and absorption without adverse effects on the growth performance of Black Sea salmon juvenile. © 2022 Osman Tolga Özel et al., published by Sciendo
Influence of laurel (Laurus nobilis) essential oil on gut function of Black Sea salmon (Salmo labrax) juveniles
Get PDFThe present work investigated the efects of dietary incorporation of laurel (Laurus nobilis) essential oil on the zootechnical performance and digestive physiology of juvenile Black Sea salmon (Salmo labrax). In this trial, 15 fberglass tanks (39×39 cm square and 33 cm high) were used. Forty-fve fsh (3.52±0.01 g) were placed randomly per tank. Fish were fed for 90 days with the diet containing 50, 100, 200, or 400 mg kg−1 laurel (Laurus nobilis) essential oils, respectively. The work was performed in the recirculating aquaculture system (RAS) operating with freshwater. Fish were manually fed 3%
level of live weight during the experiment period. Final weight (FW), weight gain (WG), feed conversion rate (FCR), and
specifc growth rate (SGR) were not afected by laurel essential oil supplementation. Dietary laurel essential oil (50 mg kg−1)
afected positively the surface area of fsh intestinal villus that required for digestion. Both villus height and villus width
were afected positively in fsh fed with 50 mg laurel essential oil kg−1. While incorporation with 100 mg laurel essential oil
kg−1 increased the total α-amylase enzyme, 50 mg laurel kg−1 increased lipase enzyme. Moreover, 50 mg laurel essential
oil kg−1 increased lactic acid bacteria (LAB) count in fsh. Besides, 50 mg laurel essential oil kg−1 reduced the number of
total coliform and E. coli
The effects of aquaculture activities on species composition and diversity of native freshwater fish populations
Get PDFThe rapid development of the aquaculture industry in recent years and the increase in the intensity of production has raised questions regarding potential environmental impacts. Understanding intra- and interspecific relationships between native and cultured species is important for sustainable use of natural resources. This study investigated the spatial and temporal effects of a fish farm constructed next to a river on the relative abundance and diversity of natural fish populations. Sampling was conducted at three stations, upstream and down stream from a trout farm and at a control site, on Kocabas stream in Çanakkale (Turkey) monthly between August 2015 and July 2016. There was no significant difference among the three stations in fish diversity. However, a remarkable seasonal and spatial variation in the composition and relative proportion of the indigenous fish assemblage were observed among the three stations. In conclusion, the fish farm might have influenced species composition and relative abundances particularly at the downstream station
