The experiment was carried out using escaped rainbow trout (weights between 268 and 310 g) caught in Seyhan Dam Lake, Adana, Turkey and three groups of rainbow trout (weights between 226 and 277 g) cultured in concrete freshwater ponds, in freshwater cages in Seyhan Dam Lake and in marine cages in Black Sea by private companies. Proximate composition and the fatty acid profiles of the fishes were determined. Analysis of the proximate composition of the present study revealed that the escaped rainbow trout flesh to have the highest water (74.23%) and the lowest lipid (4.47%) content while lowest level of moisture and highest levels of lipid was observed in farmed fish in ponds (68.69% and 7.78%). According to the results of fatty acid analysis, the highest saturated fatty acid (31.3%) and the lowest polyunsaturated fatty acids (PUFA) (26.51%) levels were in the escaped group obtained from wild, while PUFA levels were higher in the cultured groups. On the other hand, the levels of n3/n6 ratio were higher in escaped and marine cages groups (2.71 and 2.58) than in ponds and Dam Lake cages groups (1.75 and 1.33). According these results, rainbow trout from all groups studied are a desirable food item for human consumption. ARTICLE HISTORY

This study was designed to investigate the effects of starvation and re-feeding cycles on the growth performance and body chemical composition of Oncorhynchus mykiss juveniles. A total of 360 juveniles with initial mean weights (IW) of 8.46 AE 0.07 g (n = 360) were stocked into 400-L tanks in triplicate for each group, with 30 juveniles per tanks. The control group received regular feed, as is the common practice. The three other groups were periodically starved: 1 day starvation followed by 6 days re-feeding (S1), 2 days starvation followed by 5 days re-feeding (S2) and 3 days starvation followed by 4 days re-feeding (S3). The experiment lasted for 10 weeks, over the course of which the water flow rate was 4 L min À1 and the water quality parameters determined as: temperature 14.4 AE 1.1°C, oxygen 8.2 AE 0.4 mg L À1 and pH 7.5 AE 0.2. At the end of the study, S1 had the best growth performance (final weight, specific growth rate, average daily growth) of all test groups (P < 0.05). The lowest daily feed intake (DFI) and growth performance parameters were observed in S3 (P < 0.05), while protein efficiency ratio (PER), net protein utilization (NPU) and lipid efficiency ratio (LER) were higher in the S3 fish group than in the other groups (P < 0.05). Whole body protein and lipid contents were highest in S1 fish. The hepatosomatic index (HSI) and viscerosomatic index (VSI) were significantly different among groups (P < 0.05). Feed conversion ratio (FCR) was significantly lower in starvation groups S1, S2 and S3 than in the control (P < 0.05). Compensation coefficient (CC) values were higher than 1 in all starvation groups. The concluding indicate that rainbow trout exposed to 1 and 2 days of starvation in week cycles could achieve over compensation compared to the control. Additionally, partial growth compensation and improved feed utilization could be achieved in a starvation group within 3 days in a week, by beginning with the juvenile size over a 10-week experimental period.

Vegetable oils (VOs) are preferred by the aquafeed industry as alternative oil sources to fish oil (FO) for sustainable aquaculture production because they decrease catching pressure for wild fish stocks, and compared with FO, VOs have higher annual production, easier accessibility and lower prices (Bayır et al., 2011). VOs are rich sources of 18C fatty acids (FAs), but their n-3 highly unsaturated

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OBJECTIVE: Reactive oxygen species and oxygen free radicals cause oxidative damage to lipids, proteins, and cell DNA in the cell membrane. Although many DNA products are produced during oxidative DNA damage, 8-hydroxy-2´-deoxyguanosine (8-OHdG) is the most common one, since it can be produced in in vivo environment. In recent years, diving has been done quite frequently for business and sports purposes all over the world. Increased environmental pressure in diving leads to hyperoxia and causes oxidative stress. METHODS:The acute effects of diving on DNA damage were evaluated by comparing 8-hydroxy-2´-deoxyguanosine values of 15 professional diver groups before and after diving. In addition to the demographic characteristics, the serum 8-hydroxy-2´-deoxyguanosine levels of these 15 divers were compared with the control group consisting of nondiving medical students to examine the chronic effect of diving on DNA damage. RESULTS:After deep dive, the amount of 8-hydroxy-2´-deoxyguanosine increased significantly in the diver group and acute DNA damage was observed (T1: 38.86±4.7; T2: 51.77±4.53; p<0.05). In the control group, the amount of 8-hydroxy-2´-deoxyguanosine was insignificant (C1: 47.48±3.73; T1: 38.86±4.7; p>0.05).CONCLUSIONS: It was found that air dives caused an increase in serum 8-hydroxy-2´-deoxyguanosine levels, leading to acute oxidative stress and aging. However, there is no chronic side effect, according to the study of samples taken from the control group. This was thought to be due to the relative sedentary life of the control group. The duration of the effect or the ability to return to normal values should be investigated with further studies planned with large populations.

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Marine litter, which can be seen in almost all seas in recent years, is a serious problem for the environment. Similarly, the same problem also exists in Turkey's seas. This study was carried out in 4 different areas, each of which is 100m², in the Yumurtalık Fishing Port in İskenderun Bay. Marine litter was removed from the seabed by diving in these selected areas in April 2016 and June 2017. In the study, a total of 157.2 kg of rubber (49.5%), 118.9 kg of glass (37.4%), 21.61 kg of plastic (6.8%) and 19.94 kg of metal (6.3%) marine litter were detected and removed. It was determined that the marine litter extracted in 2017 was less by weight compared to 2016 (p

Antioxidants are used as additives in many foods offered for human consumption. The most important protein source foods are also aquaculture products. Antioxidants are used to prevent oxidation problems in the feeds used in the production of these products. The task of antioxidants is to prevent rancidity of fats and to keep feeds stable. Fish fed with oxidized feeds experience many negative effects such as growth retardation, low feed utilization, weak immune system and reduced resistance to diseases. As a result, it can cause great economic losses along with fish losses. Synthetic antioxidants have been used successfully for many years. However, in recent years, some restrictions and regulations have been introduced in the use of synthetic antioxidants. Therefore, natural antioxidants have begun to replace synthetic antioxidants. The sources of natural antioxidants are quite abundant, such as fruits, vegetables, plant extracts, marine macro and microalgae. In recent years, researches on these natural antioxidants and their use in fish feeds have been increasing.