Evaluation of the health of Mediterranean mussels (Mytilus galloprovincialis Lamarck, 1819) distributed in the Çanakkale strait, Turkey.

The observation of mortality in Mediterranean mussels (Mytilus galloprovincialis) distributed in the Çanakkale Strait in recent years was influential in developing the research question for this study. In this study, the presence of bacteria (Vibrio spp.) and parasites (Marteilia spp. and Haplosporidium spp.) in mussels collected from Kumkale, Kepez, and Umurbey stations in the Çanakkale Strait was investigated seasonally. Microbiological findings, histopathology, oxidative stress enzymes and their gene expressions, lipid peroxidation, lysosomal membrane stability, and changes in haemolymph were examined. In summer samples, both the defence system and the extent of damage were higher in gill tissue. In winter samples, enzyme activities and lipid peroxidation were found to be predominantly higher in digestive gland tissues. Histological examinations and Hemacolor staining revealed the presence of protozoan cysts, and for bacterial examination, molecular analysis performed after culturing revealed the presence of 7 Vibrio species. While the total numbers of heterotrophic bacteria detected in all samples were at acceptable levels, the predominance of Vibrio spp. numbers among the total heterotrophic bacteria detected in almost all samples were noteworthy. The total hemocyte count was calculated as 5.810(4)±0.58 (cells/mm3) in winter and 7.210(4)±1.03 (cells/mm3) in summer. These factors are considered to be possible causes of mussel mortality.

Influence of laurel (Laurus nobilis) essential oil on gut function of Black Sea salmon (Salmo labrax) juveniles.

The present work investigated the effects 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 fiberglass tanks (39 × 39 cm square and 33 cm high) were used. Forty-five fish (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 specific growth rate (SGR) were not affected by laurel essential oil supplementation. Dietary laurel essential oil (50 mg kg-1) affected positively the surface area of fish intestinal villus that required for digestion. Both villus height and villus width were affected positively in fish 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 fish. Besides, 50 mg laurel essential oil kg-1 reduced the number of total coliform and E. coli.