Erkan Can

The use of kefir as potential probiotic in Çoruh trout (Salmo coruhensis): Effects on growth performance and immunoglobulin (IgM) levels

The objective of this study was to evaluate the effects of three different rates of kefir on growth performance and immunoglobulin (IgM) levels of Coruh trout ( Salmo coruhensis ). The experiment was carried out with the four following treatments: Control group (not supplemented kefir), D1, D2 and D3 (kefir supplemented diet 10, 20, 40 g kg -1 fish body mass, respectively). Condition factor (CF), food conversion ratio (FCR), survival rate, and specific growth rate (SGR) were monthly determined and IgM level was measured at the end of the 4 months. Survival ranged from 88.2 to 89.1%, and was independent of dietary treatments (P>0.05). The highest specific growth rate was found for the fish fed D2; although, there was no significant difference in growth parameters between the control, the fish fed D1, D2 and D3 (P>0.05). However, diets contained kefir (D1, D2) increased immunoglobulin level in S. coruhensis (P<0.05). It can also be concluded that kefir is crucial for fish production as a potential probiotic. Keywords: Salmo coruhensis , kefir, probiotic, growth, immunoglobulin (IgM)

Effect of dietary kefir on the digestive and liver enzymes activities, and glucose level of Coruh trout, Salmo coruhensis (Actinopterygii: Salmoniformes: Salmonidae)

ly and can be beneficial for the aquatic animals through: improving their disease resistance and reducing malformations; increasing their growth performance, body composition; improving their gut morphology as well as the microfloral balance (Suzer et al. 2008, Merrifield et al. 2010, Ekici et al. 2011). The majority of probiotics have the ability to survive the passage through the intestinal tract (Verschuere et al. 2000). The probiotic bacteria produce vitamin and important digestive enzymes and provide minerals and trace elements (Holzapfel et al. 1998). Kefir, which is a probiotic product, became most popular feed additive for humans and recently also for animals (Guven et al. 2003). Kefir alters the intestinal microflora and thus exerts beneficial health effect on the exposed organism (Schrezenmeir and de Vrese 2001) and stimulates digestion of other foods, decreases the cholesterol content in blood and improves salivation and excretion of gut and pancreatic enzymes and peristalsis (Anonymous 2013). Hematological parameters such as activity of enzymes (alanine aminotransferase, ALT; aspartate aminotransferase, AST; lactate dehydrogenase, LDH; lipase, amylase) and glucose level are used as indicators of the physiological status of fish (Bansal et al. 1979). The salmonid species—Coruh trout, Salmo coruhensis Turan, Kottelat et Engin, 2010—which was only recently ACTA ICHTHYOLOGICA ET PISCATORIA (2014) 44 (2): 167–170 DOI: 10.3750/AIP2014.44.2.13

Influence of stock density on digestive enzyme activity (trypsin), heat shock protein 70 (HSP70), and oxidative stress biomarkers of narrow clawed crayfish, Astacus leptodactylus Eschscholtz, 1823 (Decapoda, Astacidae)

Stocking density causes changes in behaviour and physiology of aquatic animals and high density can cause oxidative damage in living cells. Therefore, experiments were designed to investigate the effects of stocking density on the oxidant-antioxidant response (glutathione (GSH), glutathione peroxidase (GSH-Px), catalase (CAT), and malondialdehyde (MDA)), digestive enzyme activity (trypsin), and heat shock protein 70 (HSP70) of narrow clawed crayfish ( Astacus leptodactylus ). The experiment was conducted to assess effects by stocking 3, 6, 9 and 12 crayfish/m 2 . Crayfish were stocked into 12 fiberglass tanks, three replicates per treatment and fed for 45 days. Our results indicated that activity of GSH-Px, MDA, and GSH levels increased in hepatopancreas (p<0.05) and muscle tissues (p<0.05) with increasing stock concentration while CAT activity decreased (p<0.05). Trypsin and HSP70 insignificantly increased in haemolymph. In conclusion, oxidative stress biomarkers were negatively influenced by increased quantitative changes in stocking density.

Seasonal variation in food preference of the brown trout Salmo trutta macrostigma (T., 1954) from Uzungöl Stream, Turkey

The present study is aimed to provide information on the abundance of natural foods of Salmo trutta macrostigma (T., 1954). Fish were captured from Uzungol Stream in Trabzon, Turkey between March 2009 and May 2010. It was investigated whether the dietary preferences of trout (S. t. macrostigma) change on account of seasons. Captured fish were measured 17.11 ± 4.65 cm (S.D.) (range 5 to 30 cm), 60.38 ± 48.52 g (S.D.) (range 2.34 to 250.84) (n = 163), respectively. The condition factor of trout calculated 1.00 ± 0.5 (S.D.) (range 0.57 to 1.58) (n = 163). The age range was between 0 and 8 years old. Stomach contents were analyzed using two methods, the frequency of occurrence and numerical method. A total of 11 prey groups were identified in the diets of brown trout living in Uzungol Stream.Prey groups were consisted of Trichoptera, Clitellata, unidentified Insecta, Coleoptera, Ephemeroptera, Haplotaxidae, Diptera, Verenoide, Plecoptera, Hymenoptera and Arachnidae. Analyses of stomach contents showed that the trout feed basically on Arthropoda and Annelidae. Seasonal variation of different food items showed that a high percentage of occurrence of Clitellata were recorded during both winter and autumn, while the highest percent of Coleoptera occurred during summer. Key words: Uzungol stream, Salmo trutta macrostigma, stomach contents, frequency of occurrence, numerical method, seasonal variations.