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    Aquaculture pollution and solutions
    (Ege Univ, 2006) Tekinay, Ahmet Adem; Guroy, Derya; Cevik, Nazan
    Aquaculture pollution mainly originates from the physical and chemical characteristics of feed and the applied feeding management. The production of fish feed by using the extruder technology prevents the dust and broken particles formation by enhancing the water stability of feed. Feed loss is prevented by controlling the sinking rates of feed. By using the appropriate mechanical equipment during feed production, the feed density can be adjusted according to the freshwater and marine environment. Instead of oil spraying, the use of vacuum coating for oil addition of feed prevents oil leakage into the aquatic environment. The choice of highly digestible feed ingredients with low cellulose content and the application of heat treatment (85 - 90 degrees C) for an appropriate period of time to feed in the preconditioner decreases fecal waste production by increasing carbohydrate digestibility. The balancing of the Nitrogen: Phosphorus and Protein: Energy ratios in the feed formulations provide the decreasing of the amount of dissolved ammonium, and phosphorus released to the environment. The pollution, due to fish feeding, may be also minimized through developing feeding tables according to the Thermal Growth Coefficient (TGC) of fish based on the characteristics of the fish farms.
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    Current status of organic fish production
    (Ege Univ, 2006) Tekinay, Ahmet Adem; Guroy, Derya; Cevik, Nazan
    Fish that are produced under natural conditions in accordance with the principles of organic agriculture without any use of preservative additives and without any genetic modifications, that are fed feed produced from natural raw materials, that are certified by a qualified institution are defined as 'organic fish'. Organic fish production is a production model that emphasizes human health without using pesticides, chemical and genetically modified products as well as ensuring animal welfare by decreasing the stocking density. This alternative model is used in many developed and developing countries in the world and the demand for this product has been the cause of increase in production amount and species variety in the market, although the model comprises 0,01% of the world aquaculture production. However organic aquaculture production has not been developed as rapid as organic agriculture. One of the most important reasons of this is the absence of international standards issued for organic aquaculture production. In this paper, the production principles of a number of authorized institutions certifying organic aquaculture are comparatively discussed.
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    ENVIRONMENTAL IMPACT OF TROUT FARMS ON THE ESEN STREAM (MUGLA), TURKEY
    (Parlar Scientific Publications (P S P), 2010) Tekinay, Ahmet Adem; Cevik, Nazan; Guroy, Derya
    The purpose of the present study was to evaluate the environmental effects of four trout farms on the water quality of the Esen Stream, South-Western Turkey, between February and December 2006. Water quality was monitored by bi-monthly sampling inlet and outlet water of each farm, at the same hour of the sampling day. The dissolved oxygen (DO) concentrations of the effluent water of the farms A, C and D were significantly lower compared to the inlet DO levels (p<0.05). Although an increase in the biochemical oxygen demand (BOD(5)), chemical oxygen demand (COD), total phosphorus (TP) and total nitrogen (TN) was observed in the effluents of all farms, this increase was significant only for the COD value of farm D (p<0.05). The total annual phosphorus and nitrogen loads of the farms on the receiving water were estimated to be 37.575 tons and 197.55 tons, respectively. The TP load of the farms in terms of kg P per ton of fish produced per farm were found to be between 10.82 and 12.32, while the TN load was in the range of 58.77 and 66.18 kg N per ton of fish produced.
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    Functional food products and ingredients with the increasing varieties in the world markets have enlarged their market share
    (Ege Univ, 2006) Yılmaz, Emin; Tekinay, Ahmet Adem; Cevik, Nazan
    In general, a food product is defined functional if it protect from diseases and/or has a therapeutic effect and this effect should be proved via scientific investigations beside its basic physiological functions. In this regard, natural functional products prepared by formulation and ingredients are used in the food sector. Seafood products are important sources for functional food products and ingredients. Fish and fish liver are the main sources of omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Fish oils with their proved functional properties are the most frequently used functional products in food and pharmaceutical industry. The enzymes obtained from various aquatics such as trimethylamine oxide demethylase, thiaminase, carnosinase, trypsin, etc. have both specific sources and application areas. These enzymes are important in bioclinical chemistry and organic synthesis sectors together with sectors such as food, paper and pharmaceutics. Beside, seafood products are the main sources of a number of bioactive molecules such as protamins, holotoxins, ocadaic acid, manolite, squalamine. As some of these compounds are used as food additives, most of them are used in drug production. Agar, carrageenan, chitin, chitosan, gelatine are widely used in food and food packaging industries and at the same time these products have been proved to have functional properties. Other important functional products of marine origin are vitamins (especially A and D), pigments, microalgal and spirulina products, protein isolates and flavour ingredients. The most common functional products of marine origin are presented in this review.
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    The Environmental Effect of a Land-Based Trout Farm on Yuvarlakcay, Turkey
    (Foundation Environmental Protection & Research-Fepr, 2009) Tekinay, Ahmet Adem; Guroy, Derya; Cevik, Nazan
    The objective of this study was to assess the environmental impact of one of the biggest flow-through rainbow trout farms located in South-Western Turkey between February and December 2006. The feeding water is obtained from the Yuvarlackay Stream (Mugla, Turkey) at a mean flow rate of 2.86 Litre s(-1) per ton of the annual fish production (700 t year(-1)) with drum Filtration used for the effluent treatment of the farm. Bi-monthly sampling was conducted from the inlet and discharge water (before and after treatment) at the same hour of each sampling day No significant differences in total nitrogen (TN), total phosphorus (TP), biochemical oxygen demand (BOD(5)), and chemical oxygen demand (COD) were found in the effluent, although these parameters were found to have increased in the discharged water. The dissolved oxygen (DO) and pH of the effluene water were found to be significantly affected by the fish farming activities. The effluent treatment efficiencies were found to be 7.77% for TP, 8.67% for TN, 16.58% for BOD5, and 13.16% for COD, respectively The annual TP load of the trout farm after effluent treatment was found to be 5.68 kg P per ton of fish produced, and 5.30 kg P per ton of feed used, respectively. The average TP load without any effluent treatment determined via chemical and biological methods was 7.66 and 10.46 kg P per ton of fish produced, respectively.
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    The mineral composition of kefir produced from goat and cow milk
    (Wfl Publ, 2013) Turker, Gulen; Kizilkaya, Bayram; Cevik, Nazan
    The mineral composition of kefir produced from cow and goat milk was determined. The macro (Ca, P, K, Na and Mg) and microminerals (Cu, Fe and Zn) were determined both in milk and kefir samples. The Ca/P ratio in kefir produced from cow and goat milk was 1.32. The Ca, P, Mg, Cu and Fe levels were significantly higher in kefir produced from cow milk than those in cow milk; the K and Na concentrations decreased in kefir produced from cow milk (P<0.05) while there was no change in the Zn levels. The concentrations of Ca, P, Na and Mg increased in kefir produced from goat milk while the levels of K and Fe were significantly decreased (P<0.05). No changes were recorded for Cu and Zn levels in goat milk and kefir produced from goat milk. Kefir produced from goat milk was a better source for Ca, P, K, Na and Mg minerals.