This study was conducted to determine the effect of age, sex and weight on the middle intestine villi morphology of fifth-generation Black Sea trout (Salmo labrax Pallas, 1814). The fish were kept in the freshwater ponds (June-October) and marine cages (November-May) to provide the life cycle of species. Intestine tissue samples were taken during period when fish were kept in marine cages. Our results showed that, middle intestine villi morphology changed depending on fish age (I, II, III, IV and V years old) and different live weight (low weighted and high weighted) of similar ages (16 months old). The lowest intestine villi development was obtained in I years old fish. This was followed by II years old fish. The highest intestine villi development was obtained in III years old fish. Besides, intestine villi development of high weighted fish was higher than those of low weighted fish. However, it was found that middle intestine villi morphology did not changed depending on sex. Karadeniz Alabalığı (Salmo labrax Pallas, 1814)'nın Bağırsak Villi MorfolojisiÖz: Bu çalışma, 5. (F5) nesil Karadeniz alabalığı (Salmo labrax Pallas, 1814)'nın bağırsak villi morfolojisi üzerine yaş, cinsiyet ve ağırlığın etkisini belirlemek için yapılmıştır. Türün doğal yaşam döngüsünü sağlamak için, balıklar tatlısu havuzlarında (Haziran-Ekim) ve deniz kafeslerinde (Kasım-Mayıs) tutulmuştur. Bağırsak doku örnekleri, balıkların deniz kafeslerinde tutulduğu dönemde alınmıştır. Çalışmada elde edilen sonuçlara göre, orta bağırsak villi morfolojisi balığın yaşına (I, II, III, IV ve V yaş) ve aynı yaştaki balığın (16 aylık yaş) farklı canlı ağırlığına (düşük ve yüksek ağırlıklı) bağlı olarak değişmiştir. En düşük bağırsak villi gelişimi I yaşlı balıklarda görülmüş, bunu II yaşlı balıklar takip etmiştir. En yüksek bağırsak villi gelişimi ise III yaşlı balıklarda görülmüştür. Ayrıca yüksek ağırlığa sahip balıkların bağırsak villi gelişimi düşük ağırlıklaki balıklardan daha yüksek bulunmuştur. Ancak orta bağırsak villi morfolojisi üzerine cinsiyetin etkisinin olmadığı tespit edilmiştir.

In this research, the culture characteristics of the fifth generation of Black Sea trout (Salmo trutta labrax PALLAS, 1814) were evaluated. First of all, trout were cultured in recirculating aquaculture system (RAS) and they kept in RAS until smoltification. After that, they were transported to marine cages till market size. Thus, the ratios of specific growth rate (SGR), feed conversion (FCR), mortality and condition factor (CF) were specified from hatching to 16 th month and the results were evaluated as pre-smoltification and after-smoltification individually. Moreover, the meat yield and proximate composition of Black Sea trout's fifth generation was specified in market size. Samplings were carried out monthly between February 2014 and May 2015. Fish were started to feed in 0.105±0.007g until they reached to 335.50±44.39g in May 2015. According to results; SGR, CF, FCR and mortality were determined as between 0.98-2.70, 0.86-1.15, 1.02-1.30 and 7.67-7.78% until smoltification stage, respectively. However, they were detected between 0.68-2.36, 1.04-1.20, 0.98-1.35 and 0.01-5.82% after smoltification. Also, the meat yield, viserosomatic index (VSI) and hepatosomatic index (HSI) were found to be 60.30%, 9.28% and 1.65% in market-size respectively. According to chemical analyses, trout meat contains crude protein as 15.22%, fat as 7.21%, ash as 1.51% and water (moisture) as 75.17%. In the view of the results, culture characteristics, proximate composition and meat yield were found similar to other cultured trout species. With these features, the fifth generation can be recommended to aquaculture sector considering the economic value of the Black Sea trout in Turkey.

This 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 fed with diets have at different levels 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±0.01g were fed by hand 3% level of live weight for 90 days. At the end of the study, feeding with oregano EO supplementation didn’t significantly affected 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 affect positively digestion and absorption without adverse effects on the growth performance of Black Sea salmon juvenile.

The aim of this study wasto determine the optimal dose and the time required to reach a stable level of anaesthesia using clove oil and benzocaine on Siberian sturgeon fry (Acipenser baerii Brandt, 1869) with a mean length of 10.0±0.93 (7.2-12.0) cm and weight of 4.1±0.95 (2.1-6.4) g, and to compare the effects of them on feed intake after anaesthesia. In addition, the survival time and relationship between exposure duration and recovery time in 96 min with the optimal concentrations of these two anaesthetics were examined as part of the anaesthesia procedure. Effective concentrations (EC 50 ) were estimated to be 356 (330-381) mg/L of clove oil and 37 (33-40) mg/L of benzocaine for 3 minutes with 95% confidence limits. The recovery time with clove oil was longer than with benzocaine at 6, 12, 24 and 48 minutes (P<0.05). The mean lethal times (MLT 50 ) were estimated as 37.2 (5.1-69.3) min for clove oil and 63.0 (6.1-120.0) min for benzocaine with 95% confidence limits. Feed intake in fish treated with clove oil and benzocaine occurred within ten minutes, but the effect of both anaesthetics on feed intake continued for 4 h. However, it was determined that the effect of clove oil on feed intake was less than that of benzocaine.Keywords: Siberian sturgeon, Anaesthesia, clove oil, benzocaine, feed intake. Sibirya Mersini (Acipenser baerii Brandt, 1869)'nde Benzokain ve Karanfil Yağı Kullanımının Yem Alımına Etkisi ÖzetBu araştırmanın amacı, Sibirya mersin balıklarının (Acipenser baerii Brandt, 1869) bayıltılması için en uygun karanfil yağı ve benzokainin dozlarını belirlemek, anesteziye maruz kalma süresinin ayılma süresine etkisini incelemek ve bu bayıltıcıların anesteziden sonra yem alımına etkilerini karşılaştırmaktır. Ayrıca, anestezi işleminin bir parçası olarak bu iki bayıltıcının en uygun konsantrasyonlarında 96 dakika içinde yaşama suresi ve anesteziye maruz kalma suresi ile ayılma suresi arasındaki ilişki incelenmiştir. Çalışmada ortalama boyları 10,0±0,93 (7,2-12,0) cm ve ağırlıkları 4,1±0,95 (2,1-6,4) g olan yavru balıklar kullanılmıştır. Bu balıkların karanfil yağı ve benzokain ile 3 dakika içinde bayılmaları için etkili konsantrasyonlar (EC 50 ) %95 güven sınırları ile sırasıyla 356 (330-381) mg/L ve 37 (33-40) mg/L olarak tahmin edilmiştir. Karanfil yağı ile bayıltılan balıkların ayılma suresi 6, 12, 24 ve 48 dakikalarda benzokainden daha uzun olmuştur (P<0,05). Karanfil yağı ve benzokain için ortalama ölüm süresi %95 güven sınırları ile sırasıyla 37,2 (5,1-69,3) ve 63,0 (6,1-120,0) dakika olarak tahmin edilmiştir. Karanfil yağı ve benzokain ile bayıltılan balıklar 10 dakika içinde yem almaya başlamış, fakat her iki anestezinin de yem alımına etkisi dört saate kadar devam etmiştir. Ama karanfil yağının yem alımına etkisinin benzokainden daha az olduğu belirlenmiştir.Anahtar Kelimeler: Sibirya mersini, bayıltma, karanfil yağı, benzokain, yem alımı.

In this study, reproductive performances of F5 and F6 generation hatchery-originated female Black Sea salmon (Salmo labrax) were evaluated to determine the effects of the ongoing selective breeding program. The study was conducted in freshwater pools and marine cage systems between 2018 and 2021. For the study, 53 specimens from F5 generation females with an average length of 52.71±7.08 cm and weight of 1561.29±639.76 gr, and also 56 broodstıcks specimens from F6 generation females with an average length of 51.92±5.35 cm and weight of 1506.12±417.28 gr were used. Gonad maturity controls and spawning studies were carried out in the 2018-2019, 2019-2020 and 2020-2021 breeding periods along the entire season, lasting from November to January. The number of ovulating females, their fecundity, egg diameters and fertilisation rates of eggs were recorded. In all seasons, 36.17% of F5 females ovulated in November, and the remaining females (63.83%) ovulated in December. Ovulation time in F6 females also showed a similar pattern of 1/3 of females (37.40%) ovulating in November and the remaining majority (62.60%) ovulating in December. According to the results, total egg yields as 4439.31±1675.69 and 4112.08±1041.16 egg/broodstock, relative egg yields as 2313.44±278.48 and 2345.76±516.30 egg/kg, egg diameters as 5.08±0.19 and 5.21±0.17 mm, and fertilisation rates as 96.78±3.24% and 96.63±3.73% were determined for F5 and F6 generations, respectively. In both generations, as the size of the broodstock increases, the total egg production increases (F5: r=0.9169, F6: r=0.74254), while the relative egg production (F5: r=-0.2526, F6: r=-0.3486) decreases. When the total egg yields and fertilisation rates were compared, the difference between the F5 and F6 groups was insignificant (p≤0.05). The condition factors of the two generations were found to be statistically similar (p≤0.05).