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Öğe According to Canonical Correlation, the Evaluation of Bluefish (Pomatomus saltatrix) Blood Chemistry(Medwell Online, 2010) Bulut, Musa; Gultepe, Nejdet; Mendes, Mehmet; Guroy, Derya; Palaz, MustafaBlood chemistry parameters can provide essential information on the physiological status of the animal and therefore allow accurate evaluations of the general health status. Canonical correlation analysis is a fundamental statistical tool. The goal of canonical correlation analysis is to evaluate the relative contribution of each variable to the derived canonical functions in order to explain nature of the relationships. CCA was used to determining, whether the blood protein parameters are related in any way to the blood lipids, enzymes, minerals. However, a linear association between predictor variables (blood proteins) and dependent variables (lipids, enzymes and minerals) were determining. These analyses results shown that canonical correlation analysis can be using prediction of relationships from blood proteins with other blood chemistry parameters.Öğe Aquaculture pollution and solutions(Ege Univ, 2006) Tekinay, Ahmet Adem; Guroy, Derya; Cevik, NazanAquaculture 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.Öğe Color intensity and growth performance of common clownfish (Amphiprion ocellaris) enhanced by dietary Spirulina (Arthrospira platensis)(Springer, 2022) Guroy, Derya; Karadal, Onur; Mantoglu, Serhan; Kusku, Halit; Guroy, BetulIn this study, the effect of dietary Spirulina (Arthrospira platensis) on color intensity, growth performance, total ammonia-nitrogen excretion (TAN), and profitability of common clownfish (Amphiprion ocellaris) was investigated. Three isoproteic (46%) and isolipidic (13%) diets were formulated as one control (C) and two different levels (15 and 30%) of Spirulina (SP15 and SP30) substituted for fish meal and cornmeal. Ten clownfish (initial body weight of 0.55 +/- 0.04 g) per aquarium were distributed to nine glass aquariums (60 L) with three replicates. Fish were hand-fed a day to the satiation thrice. Clownfish were weighed in bulk, and the photographs were taken biweekly during the 12-week experiment. The determined regions of the images were standardized with a raster graphics editor and recorded the color parameters by considering both CMYK (cyan magenta yellow key) and RGB (red green blue) models. After the feeding trial, fish were starved for 3 days, and the total ammonia-nitrogen (TAN) was analyzed with the ammonia salicylate method on the next day for 12 h. At the end of the trial, the final mean weights (FMW) and specific growth rates (SGR) of SP15 (FMW: 1.95 +/- 0.18 g, SGR: 1.75 +/- 0.04%/day) and SP30 (FMW: 2.05 +/- 0.14 g, SGR: 1.81 +/- 0.05%/day) were significantly higher than the C (FMW: 1.68 +/- 0.12 g, SGR: 1.58 +/- 0.06%/day) group (P < 0.05). Both color models have proved the enhancement of the skin coloration (significant improvements were recorded in the colors, including red, green, magenta, and key, P < 0.05). Also, it was determined that the TAN was decreased with the increase of the Spirulina level (29.8, 22.9, and 17.6 mg-N/100 g fish/12 h for C, SP15, and SP30, respectively) in the diet (P < 0.05). However, a high level of Spirulina in the diet negatively affected profitability. Consequently, common clownfish's growth, color, and TAN improved with the dietary Spirulina. Considering that Spirulina is an expensive raw material, adding it into the diet at medium levels (15%) is recommended.Öğe Current status of organic fish production(Ege Univ, 2006) Tekinay, Ahmet Adem; Guroy, Derya; Cevik, NazanFish 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.Öğe Effect of autoclaved Ulva meal on growth performance, nutrient utilization and fatty acid profile of rainbow trout, Oncorhynchus mykiss(Springer, 2013) Guroy, Betul; Ergün, Sebahattin; Merrifield, Daniel L.; Guroy, DeryaA feeding trial was conducted to investigate the effects of the dietary incorporation of autoclaved and raw (non-autoclaved) Ulva meal on juvenile rainbow trout (Oncorhynchus mykiss) growth, nutrient utilization, body composition, diet digestibility and fatty acid composition. An algae-free control diet and four experimental diets with either 5 or 10 % inclusion levels of raw Ulva meal (5 % = RU5; 10 % = RU10) or autoclaved Ulva meal (5 % = AU5; 10 % = AU10) were formulated. Fish were fed three times daily to apparent satiation for 12 weeks. The growth of fish fed RU10 (final weight = 76.7 +/- A 3.31 g; SGR = 2.8 +/- A 0.05 %) diet was significantly higher than that in fish fed the AU10 diet (67.5 +/- A 1.61 g; SGR = 2.6 +/- A 0.03 %). The feed conversion ratio (FCR) was significantly better in fish fed the RU10 diet (0.9 +/- A 0.06) compared with control diet (1.0 +/- A 0.06). Condition factor, viscerosomatic index and dress-out remained unaffected by dietary treatment. The hepatosomatic index (HSI) was significantly lower (P < 0.05) in fish fed the AU10 diet (1.2 +/- A 0.19) than fish fed the other diets (a parts per thousand yen1.6). The level of eicosapentaenoic acid (20:5n-3-EPA) in muscle from fish fed the RU10, AU5 and AU10 diets was significantly higher than in fish fed control diet (P < 0.05). Dietary inclusion of Ulva meals resulted in a significant increase in muscle docosapentaenoic acid (22:5n-3-DPA) levels at the end of the feeding period. The results indicate that the dietary inclusion of raw Ulva meal at levels of up to 10 % can be used without significant negative effects on the growth performance, nutrient utilization, dietary digestibility and muscle fatty acid composition. In fact, the inclusion of dietary raw and autoclaved Ulva meal elevated n-3 fatty acids levels of rainbow trout muscle.Öğe Effect of Dietary Protein Level on Growth Performance and Nitrogen Excretion of the Yellow Tail Cichlid, Pseudotropheus acei(Israeli Journal Of Aquaculture-Bamidgeh, 2012) Guroy, Derya; Sahin, Izzet; Guroy, Betul; Altin, Aytac; Merrifield, Daniel LeeA 12-week growth trial was conducted to determine the effects of dietary protein on the growth of the yellow tail cichlid, Pseudotropheus acei, and on water quality in closed recirculating systems. Six test diets were formulated to contain protein levels ranging 25-50% by substituting corn oil and alpha-starch for fishmeal. Diets were assigned to triplicate groups of 10 fish in a completely randomized design. The feed conversion ratios of fish fed the 35% and 50% crude protein diets were significantly (p<0.05) lower than that of fish fed the 30% protein diet. The protein efficiency ratio declined as the dietary protein level increased. Dietary protein levels significantly influenced total ammonia-nitrogen excretion (TAN); fish fed 50% protein excreted higher concentrations of ammonia-nitrogen than fish fed 25-35% dietary protein (p<0.05). Results suggest that inclusion of more than 35% protein in diets containing 10% crude lipid does not benefit juvenile yellow tail growth performance. Further, as TAN excretion and feed costs increased at protein levels beyond 35%, we recommend a diet containing 35% protein and 10% lipid for promoting good growth of juvenile yellow tail cichlids under the conditions used in the present trial.Öğe Effects of dietary marine sulphated polysaccharides (Algimun®) on growth performance, immune responses and disease resistance of juvenile gilthead seabream (Sparus aurata) to Photobacterium damselae subsp. piscicida(Academic Press Ltd- Elsevier Science Ltd, 2022) Guroy, Derya; Guroy, Betul; Bilen, Soner; Terzi, Ertugrul; Kenanoglu, Osman Nezih; Garcia-Suarez, Maria; Marzin, DanieleThe present study evaluated the effects of a dietary mix of marine sulphated polysaccharides, named Algimun (R) (AL), supplementation to gilthead seabream (Sparus aurata) juveniles in terms of growth performance, immune responses, and resistance against Photobacterium damselae subsp. piscicida. A total of 240 fish (initial mean weight of 6.00 +/- 0.03 g) was randomly separated into 12 tanks (400 L, 20 fish per tank) distributed in four replicates. Fish were fed three experimental diets: a basal diet (Control), and a basal diet with two inclusion rates of Algimun (R) as 3 g/kg (AL0.3) and 5 g/kg (AL0.5) for 30 days before bacterial infection with P. damselae subsp. piscicida. After a 30-day feeding-period, growth performance was significantly improved in AL0.3 and AL0.5 groups compared to the control group (P < 0.05). AL0.3 and AL0.5 groups showed significantly higher lysozyme activity and myelopemxidase activity when compared to the control group (P < 0.05). The gene expression of immune mediators (IL-1 beta, IL-6, IL-10, IL-18, TNF-alpha and COX-2) was significantly upregulated in the intestine, spleen and head kidney in AL0.3 and AL0.5 groups when compared to the control group (P < 0.05). Eight days post-challenge, the survival rate against P. damselae subsp. piscicida was numerically higher in fish within AL0.3 and AL0.5 groups compared to control (+20%). The study findings suggest that marine sulphated polysaccharides (Algimun (R)) could be used as an immunomodulator in gilthead seabream to support animal's health and boost resistance in case of disease outbreak.Öğe Effects of herbs and spice on health status of tilapia (Oreochromis mossambicus) challenged with Streptococcus iniae(Veterinarni A Farmaceuticka Univerzita Brno, 2014) Gultepe, Nejdet; Bilen, Soner; Yılmaz, Sevdan; Guroy, Derya; Aydin, SeyitEffects of different herbal extracts on the growth and immune defense of fish were researched in the last decade. The aim of this study was to determine the dietary effects of thyme (Thymus vulgaris), rosemary (Rosmarinus officinalis) and fenugreek (Trigonella foenum graecum) as a feed additive on haematology, innate immune response, and disease resistance of tilapia (Oreochromis mossambicus). In total 228 healthy fish tilapia were divided into four groups (57 fish in one group) and fed diets supplemented with thyme, rosemary and fenugreek at levels of 1%, respectively; fish in the control group were fed diet without any spices. Fish were fed ad libitum three times a day for 45 days. All fish of the experimental groups significantly (P < 0.05) enhanced phagocytic activity, haematocrit, white blood cell, red blood cell, neutrophil and monocyte counts in blood. Significant (P < 0.05) increase of plasma myeloperoxidase and lysozyme activity was found in fish receiving a feed supplemented with fenugreek after 30 days. Respiratory burst activity was non-significantly (P > 0.05) changed during the whole experiment. After 45 days of feeding, fish were injected intraperitoneally with 100 mu l of Streptococcus iniae (8 x 10 colony forming unit). The cumulative mortality was 22%, 27% and 31% in fish receiving diets supplemented with 1% thyme, rosemary and fenugreek, respectively, compared to 61% mortality in the control group. The results indicate that all three supplements used improved the haematological status, non-specific immune response and disease resistance of tilapia against S. iniae; this is the first similar study.Öğe Effects of Ulva Meal on Growth Performance of Gilthead Seabream (Sparus aurata) at Different Levels of Dietary Lipid(Central Fisheries Research Inst, 2013) Emre, Yilmaz; Ergün, Sebahattin; Kurtoglu, Adem; Guroy, Betul; Guroy, DeryaA nutrition trial was carried out to investigate the effects of inclusion of Ulva meal at different dietary lipid levels on growth performance, feed utilization and body composition of juvenile gilthead seabream, Sparus aurata. In this study, gilthead seabream with an average weight of 8.5 +/- 0.01 g were fed experimental diets for 7 weeks. The Eight isonitrogenous diets (crude protein 50%) were designed to provide 13% (13), 16% (16), 19% (19) and 22% (22) crude lipid with or without 4% inclusion of Ulva meal (13U, 16U, 19U and 22U). Final mean weight and specific growth rate (SGR) of gilthead seabream fed 22L-U were higher than that of 13L and 13L-U groups. The mean feed conversion ratio varied from 0.92 (22L-U) and 1.33 (13L and 13L-U). The present study shows that dietary low level (4%) Ulva meal at all dietary lipid levels could be used in juvenile gilthead seabream without causing any adverse effects on growth and feed utilization.Öğe Effects of Ulva rigida and Cystoseira barbata meals as a feed additive on growth performance, feed utilization, and body composition of Nile tilapia, Oreochromis niloticus(Tubitak Scientific & Technological Research Council Turkey, 2007) Guroy, Betul Kut; Cirik, Sukran; Guroy, Derya; Sanver, Feyza; Tekinay, Ahmet AdemIn a 12-week feeding trial, the effect of 2 algae meals (Ulva rigida or Cystoseira barbata) on feed intake, growth, and nutrient utilization of juvenile Nile tilapia, Oreochromis niloticus, was investigated. This was the first attempt to utilize Cystoseira barbata as a feed supplement for Nile tilapia. The fish were fed to apparent satiation with formulated diets supplemented with various levels of Ulva meal (5%, 10%, or 15%) or Cystoseira meal (5%, 10%, or 15%). A diet without algae meal served as a control diet. The highest values for weight gain were for fish fed the 5% Cystoseira diet, control diet, and 5% Ulva diet (156%, 151%, and 150%, respectively), but the values were not significantly different (P > 0.05) compared to other treatments, except for the fish fed on the 15% Ulva diet (P < 0.05), which exhibited the lowest weight gain. Fish fed the diet containing 15% Ulva meal showed the poorest feed conversion ratio (FCR). Protein and energy utilization tended to decrease in the groups fed the algae meals at the highest supplementation level of 15%. Carcass lipid levels decreased with increasing levels of Ulva meal, while an increase in carcass lipid level with increasing levels of Cystoseira meal was observed (P < 0.05). The results suggested that Ulva rigida or Cystoseira barbata meals could be used in small percentages in tilapia diets.Öğe ENVIRONMENTAL IMPACT OF TROUT FARMS ON THE ESEN STREAM (MUGLA), TURKEY(Parlar Scientific Publications (P S P), 2010) Tekinay, Ahmet Adem; Cevik, Nazan; Guroy, DeryaThe 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.Öğe Hazelnut meal in diets for seawater farmed rainbow trout (Oncorhynchus mykiss): effects on growth performance and body composition(Pagepress Publ, 2009) Bulut, Musa; Tekinay, Ahmet Adem; Guroy, Derya; Ergün, Sebahattin; Bilen, SonerA 77-day feeding trial was designed in order to assess the effect of partial or total replacement of soybean meal by hazelnut meal (HNM) on feed intake, growth performance, nutrient utilization and body composition of rainbow trout (initial mean body weight: 80.0 +/- 3.5 g) in seawater conditions. A control and three experimental diets were formulated in which soybean meal level (25.5%) in the control diet was replaced by hazelnut meal at 39.2 (HN 39), 78.4 (FIN 78) and 100% (RN 100) to provide 44% crude protein and 20% crude lipid diets. Diets were fed to 125 rainbow trout to apparent satiation by hand twice daily at 09.00 and 16.00 hours under natural photoperiod conditions. At the end of the feeding trial, fish of all groups almost tripled their body weight and no significant difference (P>0.05) was revealed in final weight or specific growth rate between treatments. However, feed conversion ratio (FCR) of the HN100 group was significantly higher than other treatments (P<0.05). There was a slightly decreasing trend in protein efficiency ratio (PER) and net protein utilization (NPU) with increasing level of dietary hazelnut meal, but it was only significant in groups of fish fed HN100. All groups of fish displayed similar carcass and muscle compositions. According to the results of the present study, it can be stated that hazelnut meal can replace soybean meal at up to 200 g kg(-1) in grow-out diets of rainbow trout without any detrimental effects on growth performance.Öğe Influence of feeding frequency on feed intake, growth performance and nutrient utilization in European sea bass (Dicentrarchus labrax) fed pelleted or extruded diets(Tubitak Scientific & Technological Research Council Turkey, 2006) Guroy, Derya; Deveciler, Emrah; Guroy, Betul Kut; Tekinay, Ahmet AdemIn an 83-day-nutrition trial, effects of feed production technique and feeding frequency on feed intake, growth and nutrient utilization were determined in European sea bass (Dicentrarchus labrax). Three thousand six hundred fish (170 +/- 2.6 g) were randomly allocated to experimental sea cages (approx. 5800 l) according to a 2 x 2 experimental plan [2 processing techniques: steam pelleted diet (P) vs. extruded diet (E); 2 feeding frequencies: twice (2) vs. 3 times ( 3)]. The P3 group consumed significantly (P < 0.05) more feed than the fish fed extruded diets, irrespective of feeding frequency. Growth rates of all groups did not display any significant difference (P > 0.05) in terms of final weight (FW) or specific growth rate ( SGR), although there was a decreasing trend in final weight (E3 > E2 > P3 > P2). Feed efficiencies (FE) of E2 and E3 fish were higher than P2 and P3 treatments (P < 0.05). No significant difference (P > 0.05) was evident for the hepatosomatic index (%), mesenteric fat index (%), viscerasomatic index (%), or dress-out (%) parameters in all treatments. The carcass and muscle components (protein, lipid, and ash) did not reveal any significant difference (P > 0.05). According to the results, feeding sea bass twice or 3 times daily with steam pelleted or extruded diet did not influence the growth; however, extruded diet improved the feed efficiency of sea bass irrespective of feeding frequency.Öğe Influence of Ulva meal on growth, feed utilization, and body composition of juvenile Nile tilapia (Oreochromis niloticus) at two levels of dietary lipid(Springer, 2009) Ergün, Sebahattin; Soyuturk, Murat; Guroy, Betuel; Guroy, Derya; Merrifield, DanielA nutrition trial was conducted to investigate the effects of dietary lipid levels and supplemental Ulva meal on growth performance, feed efficiency, nutrient utilization, and body composition of juvenile Nile tilapia, Oreochromis niloticus. Four isonitrogenous (CP 40%) diets containing 0% and 5% Ulva meal were formulated to contain 10% (low-lipid; LL) and 20% (high-lipid; HL) crude lipid. Triplicate groups of fish (similar to 10 g) were fed to apparent satiation three times daily for 16 weeks. Fish fed 5% Ulva meal showed an increased growth performance (P < 0.05) compared with fish fed non-Ulva supplemented diets, irrespective of dietary lipid level. In particular, the incorporation of Ulva meal improved specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER). Feeding fish 5% Ulva meal diets resulted in significantly lower carcass lipid content. The results indicate that 5% inclusion of Ulva meal at both dietary lipid levels improves growth performance, feed efficiency, nutrient utilization, and body composition of Nile tilapia.Öğe Optimal Dietary Protein Levels in Juvenile Electric Blue Cichlid (Sciaenochromis fryeri)(Israeli Journal Of Aquaculture-Bamidgeh, 2008) Gullu, Kenan; Guroy, Derya; Ceiik, Ihsan; Tekinay, Ahmet AdemA feeding trial was conducted to determine the dietary protein requirement of juvenile electric blue cichlids (Sciaenochromis fryeri). Groups of fish (0.50 +/- 0.01 g) were fed one of four isocaloric diets containing protein levels ranging 35-50% for 12 weeks. According to the broken-line model, the dietary protein requirement was estimated as 38.8%. The feed conversion ratio ranged from 1.73 in the 50%-protein group to 2.16 in the 35% group. There were statistically significantly differences in feed intake and protein efficiency ratio. In general, the protein efficiency ratio decreased as the dietary protein level increased. For optimum growth, feed conversion, and protein utilization, a diet containing 39-40% protein, 11% crude lipid, and 20.7 MJ gross energy/kg diet is recommended for juvenile S. fryeri.Öğe Optimum Dietary Protein Level for Blue Streak Hap, Labidochromis caeruleus(Central Fisheries Research Inst, 2010) Ergün, Sebahattin; Guroy, Derya; Tekesoglu, Haluk; Guroy, Betul; Celik, Ihsan; Tekinay, A. Adem; Bulut, MusaAn experiment was designed to determine the optimum dietary protein level of a freshwater ornamental fish, Blue streak hap (Labidochromis caeruleus). Four isocaloric fish meal based diets ranging from 30% to 45% in protein were fed to triplicate groups of Blue streak hap for 8 weeks. Fish (initial weight, 0.85 g) were reared in twelve 50 L aquarium with biological filter and controlled temperature (27.5 degrees C), in stocking density of ten fish/aquarium. Results showed that dietary protein level significantly influenced final weight, weight gain and specific growth rate of fish. Maximum growth of fish was observed in the 40% protein diet, although this was not significantly different from the 35% and 45% protein diets (P > 0.05). Specific growth rate and feed efficiency increased from 30% to 40% protein, and thereafter decreased for diet 45% protein. There were statistically significantly differences in feed intake among treatments (P < 0.05). Fish fed with the highest protein diet had lower percentage daily feed consumption values than those of fish fed with the lowest protein diet. Under the experimental conditions applied, juvenile blue streak hap, L. Caeruleus, appear to require more than 35% dietary protein for optimized growth.Öğe Replacement of fishmeal with rice protein concentrate in practical diets for European sea bass Dicentrarchus labrax reared at winter temperatures(Wiley-Blackwell, 2013) Guroy, Derya; Sahin, Izzet; Guroy, Betul; Merrifield, Daniel L.; Bulut, Musa; Tekinay, Ahmet AdemAs no information is available regarding the efficacy of using rice protein concentrate (RPC) to replace fishmeal (FM) in diets for European sea bass (Dicentrarchus labrax), a trial was conducted to determine the optimum inclusion for European sea bass juveniles. Diets were formulated to replace 25%, 50% and 75% of fishmeal with RPC. Additional high level inclusion diets (50% and 75%) were supplemented with lysine and methionine to determine if these were limiting factors. Fish (18.0 +/- 0.06g) were fed the experimental diets for 12weeks. The final mean weight and specific growth rate (SGR) were significantly higher in fish fed the control diet (diet FM) and low level RPC (diet RPC25) than in fish fed the other diets. The supplementation of the amino acids had a positive effect on growth, elevating the final weight of the high level RPC (RPC75+AA) group above that of the non-supplemented group (RPC75). However, this was still not comparable to fish fed FM and RPC25 diets. No significant differences in body composition were observed. A digestibility study demonstrated an inverse relationship between elevating inclusion levels of RPC and apparent digestibility coefficients (ADCs) for dry matter and lipid, with significantly lower values than the control being observed with RPC inclusions above 25%. The mesenteric fat index followed this trend. Circulating leucocyte levels, leucocyte ratios and serum lysozyme activity remained unaffected by dietary treatment. However, compared with the control group, fish fed RPC75, RPC50+AA RPC75+AA displayed significantly lower haematocrit values. The present study demonstrates that the inclusion of RPC at 140gkg1 (effectively replacing 25% of FM content) does not compromise European sea bass growth performance, body quality or basic haematological parameters. It is suggested that future studies including higher levels test the efficacy of additional amino acid supplementation (e.g. tryptophan).Öğe Some biological parameters of horse mackerel Trachurus trachurus (L., 1758) caught from the Dardanelles(Ege Univ, 2006) Guroy, Derya; Kahyaoglu, Gulcin; Ozen, Ozcan; Tekinay, A. AdemGrowth parameters and gonadosomatic index (GSI) (%) of 459 horse mackerel Trachurus trachurus (L. 1758) were studied in Dardanelles between September 2001 and August 2002. The age composition of the sampled population varied between 0 and 3, where the 0-age group contained the highest number of fish (59.0%). The population was composed of 57% females and 43% males, respectively. The total length varied from 8.80 to 25.90 cm and the body weight varied from 8.50 to 171.72 g. The Von Bertalanffy equation was estimated as Lt = 30.34 (1 - e (-0.255) ((t + 2.481))) for both sexes combined. Maximum monthly mean of the GSI for males (3.77%) and females (3.91%) were observed in April 2003.Öğe The Environmental Effect of a Land-Based Trout Farm on Yuvarlakcay, Turkey(Foundation Environmental Protection & Research-Fepr, 2009) Tekinay, Ahmet Adem; Guroy, Derya; Cevik, NazanThe 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.
