This study was conducted to determine changes in the growth performance and distal intestine villi morphology of juvenile Black Sea trout ( Salmo trutta labrax ) fed diets with three different protein levels (40%, 45% and 50%). It was carried out in two separate sections; freshwater (RAS) and seawater. Juvenile Black Sea trout, having average initial weights of 3.44g (freshwater) and 17.70g (seawater), were fed for 90 days. WG, SGR, FCR and survival weren’t affected by dietary treatment. However distal intestine villi length (VL), width (VW) and length to width ratio (VL/VW) were affected by dietary treatments. Villi length, width and length to width ratio in the fish fed with diet containing 50% protein in freshwater were found to be higher than those fed with other diets. Villi length in the fish fed with diet containing 50% protein in seawater was higher than those fed with other diets. Results showed that feeding with diets contained different protein levels did not effect on growth performance of Juvenile Black Sea trout, but affected on distal intestine villi morphology.

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 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.

Bu çalışmada, Karadeniz alabalığı ( Salmo trutta labrax PALLAS, 1814)’ın beşinci neslinin kültür karakteristikleri belirlenmiştir. Öncelikle alabalıklar kapalı devre yetiştiriclik ünitesi (RAS)’nde üretilmiş ve smolt boya gelene dek burada tutulmuşlardır. Sonrasında, alabalıklar deniz kafeslerine transfer edilmişler ve porsiyonluk boya gelene kadar orada tutulmuşlardır. Bu nedenle; spesifik büyüme oranı (SGR), yem dönüşüm oranı (FCR), ölüm oranı ve kondüsyon faktörü (CF) parametreleri yumurtadan çıkıştan 16. aya kadar belirlenerek sonuçlar smolt öncesi ve smolt sonrası olarak verilmiştir. Ayrıca, beşinci nesil Karadeniz alabalığının porsiyonluk boydaki et verimi de hesaplanmıştır. Örneklemeler, Şubat 2014 ile Mayıs 2015 arasında aylık olarak yapılmıştır. Balıklar 0,105±0,007g iken beslenmeye başlanmış ve Mayıs 2015’e kadar 335,50±44,39g’a ulaşmışlardır. Sonuçlara göre; smoltifikasyon öncesi SGR, CF, FCR ve ölüm oranı sırasıyla 0,98-2,70, 0,82-1,15, 1,02-1,30 ve %7,67-7,78 aralıklarında belirlenmiştir. Ancak bu parametreler smoltifikasyon sonrası 0,68-2,36, 1,04-1,20, 0,98-1,35 ve %0,01-5,82 olarak belirlenmiştir. Ayrıca; pazar boydaki et verimi, viserosomatik indeks (VSI) ve hepatosomatik indeks (HSI) değerleri sırasıyla %60,30, %9,28 ve %1,65 bulunmuştur. Kimyasal analizlere göre, alabalık eti %15,47 ham protein, %7,21 ham yağ, %1,57 ham kül ve %74,83 su (nem) içermektedir. Sonuçlar açısından, kültür özellikleri, besin bileşimi ve et verimi diğer kültüre alınan alabalık türlerine benzer bulunmuştur. Bu özellikleri ile, Karadeniz alabalığının eknomik değeri de göz önünde bulundurularak, beşinci nesil yetiştiricilik sektörüne önerilebilir.

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 trutta labrax Pallas, 1811). 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. According to the results obtained, middle intestine villi morphology changed depending on age (1, 2, 3, 4 and 5 years old) and different live weight of similar ages (16 months old). The lowest intestine villi development was obtained in 1 years old fish. This was followed by 2 years old fish. The highest intestine villi development was obtained in 3 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 didn’t changed depending on sex.

This study was conducted to determine the effect on growth performance and intestinal histomorphology of the rainbow trout (Oncorhynchus mykiss) fed diets including black soldier fly (Hermetia illucens) prepupae meal (HI) and mealworm (Tenebrio molitor) larvae meal (TM) used instead of fish meal. Six diets with HI and TM at three inclusion levels (10%, 20% and 30%) and a control diet based on fish meal were prepared. Test diets were encoded as control, HI10, HI20, HI30, TM10, TM20 and TM30. Fish (average initial weight of 34.17±0.88 g) were randomly placed (30 for each) in 500 L fibreglass tanks. Each of the seven diet treatments was tested in triplicated tanks. Fish were fed by hand at a level of 2.5% of body weight three times a day for 90 days. Results demonstrated that the growth performance and intestinal histomorphology were significantly affected by black soldier fly (HI) prepupae meal substitution (p<0.05). HI prepupae meal used instead of the fish meal had a negative effect on the growth performance, but not on the intestinal villi length. In addition, intestinal villi width decreased in fish on diets containing 10% or 20% HI prepupae meal. The growth performance and intestinal histomorphology were significantly affected by diets including TM. The diets containing 20% and 30% TM meal significantly decreased growth performance variables, but intestinal villi length increased. The results suggest that mealworm meal (10%) can be included in diets of rainbow trout at a level of 10% instead of fish meal without adversely affecting growth performance. Future studies should be expanded using a highly defatted TM and HI larvae meals.