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    The effect of feed made from fish processing waste silage on the growth of rainbow trout (Oncorhynchus mykiss)
    (Academic Journals, 2011) Guzel, Senol; Yazlak, Hasan; Gullu, Kenan; Ozturk, Ekrem
    This study researched the degree to which the growth of rainbow trout (Oncorhynchus mykiss) was influenced by pellet feed made from silage produced from waste generated by the fish food processing industry. During the 90 day trial, a completely random parcel method was used with three repetitions. The average weight of the rainbow trout was 54.05 +/- 235 g, while their average length was 17.46 +/- 0.11 cm. One hundred (100) trout were stocked (25 kg/m(3)) in each fiberglass fish feeding tank. Four different experimental groups were formed; feed without silage (control) and pellets with 25, 50 and 100% silage. Fish were fed twice per a day until they were satisfied (ad libitum). At the end of the study, the group that was fed with feed made from 50% silage increased the most in weight, followed by the control group and the groups fed with 25 and 100% silage, respectively. The average weight differences between the groups were found to be significant (P<0.05). In conclusion, it can be said that replacing the fish meal in food used to feed trout with 50% fish silage has a positive effect on growth, and that silage can be used in trout food at the aforementioned ratio.
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    The effect of lycopene on antioxidant status in rainbow trout (Oncorhynchus mykiss) reared under high stocking density
    (Elsevier Science Bv, 2014) Sahin, Kazim; Yazlak, Hasan; Orhan, Cemal; Tuzcu, Mehmet; Akdemir, Fatih; Sahin, Nurhan
    Lycopene, the major carotenoid found in tomato, exhibits health beneficial effects by virtue of its antioxidant activity. As stocking density is known as a stress factor in fish, the effects of dietary lycopene supplementation (0, 200 or 400 mg kg(-1)) on growth performance and antioxidant status in rainbow trout under normal (20 kg m(3-1)) and high (100 kg m(3-1)) stocking density were studied. Glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and catalase (CAT) activities were evaluated, as well as lipid peroxidation measured as malondialdehyde (MDA). Nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappa B), erythroid-derived 2-like 2 (Nrf2) and heme-oxygenase 1 (HO-1) levels were also assayed as an indicator of detoxifying/antioxidant defense mechanisms to cope with oxidative stress. Results showed that exposure to high stocking density depressed feed intake by 6.8% and body weight gain by 12.1%, increased plasma and hepatic MDA level by 88.5 and 124.3% and decreased hepatic SOD, CAT and GSH-Px activities by 22.1, 43.4 and 51.7%, respectively. In fish under crowded conditions, an expression of hepatic NF-kappa B was increased by 71.5%, being suppressed in Nrf2 and HO-1 by 40.6 and 42.7%, respectively. Lycopene supplementation increased linearly fish growth performance and antioxidant enzyme activity, and decreased linearly MDA concentration in both low and high stocking densities. NF-kappa B levels decreased hepatic Nrf2 and HO-1 levels increased linearly with lycopene supplementation at a greater extent in fish under low stocking condition. In conclusion, dietary supplementation of lycopene to fish reduces the detrimental effects of high stocking density on growth performance and modulates oxidative status via activating host defense system at cellular level. It appears that lycopene can be added up to 400 mg kg(-1) to rainbow trout diets to improve meat quality. (C) 2013 Elsevier B.V. All rights reserved.
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    Lycopene improves activation of antioxidant system and Nrf2/HO-1 pathway of muscle in rainbow trout (Oncorhynchus mykiss) with different stocking densities
    (Elsevier, 2014) Sahin, Kazim; Orhan, Cemal; Yazlak, Hasan; Tuzcu, Mehmet; Sahin, Nurhan
    The purpose of this study was to describe the effect of lycopene on antioxidant status, heat shock protein 70 (Hsp70), nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme-oxygenase 1(HO-1) levels in the muscle of rainbow trout (Oncorhynchus mykiss). The fish were kept at low(20 kg m(3 - 1)) or high(100 kg m(3 - 1)) stocking densities till the end of study and fed a basal diet or the basal diet supplemented with either 200 or 400 mg of lycopene kg(-1) of diet. The protein, lipid and ash contents in the muscle were not changed by the supplementation of lycopene in rainbow trout kept under high or low stocking densities. In response to increasing supplemental lycopene level, there were linear increases in lycopene levels, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities (P < 0.001) and Nrf2 and HO-1 levels of muscle; linear decreases in muscle malondialdehyde (MDA) and Hsp70 levels (P < 0.001). In conclusion, lycopene supplementation to fish reduces the detrimental effects of oxidative stress and lipid peroxidation resulting from stocking densities via activating host defence system at cellular level. (C) 2014 Elsevier B.V. All rights reserved.