Impact of sublethal di‐n‐butyl phthalate on the aquaculture fish species Nile tilapia (Oreochromis niloticus): histopathology and oxidative stress assessment

Phthalates such as di‐n‐butyl phthalate (DBP) and their esters are widely used plasticizers, their ubiquitous presence in daily life, inevitably leads to their restricted use due to important environmental pollution and health impacts and endocrine disruption potential. The aim of this study was to examine the effects of a sublethal concentration of 10 mg L^?1 DBP on haematocrit (HCT) values, gills and liver histology, malondialdehyde (MDA, 2‐thiobarbituric acid‐TBA reactivity) and reduced glutathione (GSH) levels in gills and liver tissue as oxidative stress biomarkers in the aquaculture fish species Nile tilapia (Oreochromis niloticus) after 24 (DBP‐24) and 96 (DBP‐96) h exposure. No differences were found between per cent HCT values in the 24 h exposure groups (P > 0.05). Response of antioxidant defence systems in liver and gill tissues of the fish were dependent on exposure duration and changed to a higher extent during 96 h. MDA levels in liver tissue increased in DBP treated fish in comparison to the control fish. However, the differences between the exposure and control groups were not significant (P > 0.05). A statistically significant decrease (P > 0.05) was recorded in gill MDA levels in the DBP‐96 group when compared to the control and DBP‐24 groups. The liver GSH levels were unchanged in the DBP treated fish. However, GSH levels were significantly lower in the gill tissue of the DBP‐96 group. Exposure to DBP caused several degenerative changes in the histology of gill and liver tissue. Gills displayed hyperaemia, epithelial lifting, oedema, talengiectasia, epithelial hyperplasia and fusion of secondary lamellae, whereas in liver several circulatory anomalies (hyperaemia, blood congestion and sinosoid dilatation) and vacuolization of hepatocytes were observed. Histopathological results demonstrated that the gills were more affected than the liver perhaps due to their direct contact with DBP.     

Factors affecting the reproductive efficiency in crayfish: implications for aquaculture

In recent years, crayfish aquaculture industry has been developing rapidly in different regions of the world. Crayfish aquaculture is often carried out in dams, lakes and extensive pond systems. There is an increasing demand for crayfish juvenile in aquaculture sector. Therefore, it is important to know which factors affect reproductive efficiency in crayfish. In the present review, factors affecting the reproductive efficiency of crayfish are divided into two main sections, external and internal factors. Dietary lipids, phospholipids, highly unsaturated fatty acids, protein and amino acids, vitamins and carotenoids are important external factors affecting broodstock crayfish reproduction. In addition, various external (i.e. female size, stocking density, temperature, photoperiod, sex ratio) and internal (i.e. endogenous hormones) factors affect the reproductive efficiency in crayfish. This study reviews the present knowledge with the purpose of realizing the factors that are important to reach optimal crayfish nutrition, maturation and reproduction (i.e. pleopodal egg number and quality). This review will particularly be useful for crayfish farmers and crayfish hatchery units.     

Determination of amino acid and fatty acid composition of goldband goatfish [Upeneus moluccensis (Bleeker, 1855)] fishing from the Gulf of Antalya (Turkey)

In this study, we aimed to determine the basic food components, fatty acids and amino acids, and variations in these components with months in goldband goatfish (Upeneus moluccensis) that fishing from Gulf of Antalya. As a result of the analyzes, the crude fat values were determined between 1.43 and 3.78%, and the crude protein values were determined between 20.79 and 22.16%. The most abundant fatty acids were determined: palmitic acid (C16:0), stearic acid (C18:0), palmitoleic acid (C16:1c9), oleic acid (C18:1c9), linoleic acid (C18:2n-6), eicosatrienoic acid (C20:3n-3), arachidonic acid (C20:4n-6), eicosapentaenoic acid (C20:5n-3), docosapentaenoic acid (C22:5n-6), and docosahexaenoic acid (C22:6n-3). The most abundant amino acids were determined lysine and leucine, aspartic acid, glutamic acid, alanine, and glycine. The differentiations of essential nutrient components, fatty acids, and amino acids were found generally significant (P < 0.05).

     

The harvest of the freshwater crayfish <Emphasis Type="Italic">Astacus leptodactylus</Emphasis> Eschscholtz in Turkey: harvest history,impact of crayfish plague,and present distribution of harvested populations

This review focuses on the present distribution of populations of the crayfish Astacus leptodactylus that are harvested in Turkey. It also examines the history of this harvest and the impact that crayfish plague has had on them. Crayfish plague, caused by the fungus-like organism, Aphanomyces astaci Schikora, 1906, is a severe parasite of freshwater crayfish and has caused a lot of damage to A. leptodactylus populations in Turkey since 1984. Turkey was the largest provider of A. leptodactylus to Western Europe from 1970 (or possibly earlier) until 1986. For example, the peak production was reached in the early 1980s, with over 5,000 tonnes being exported in 1984. On the other hand, as a result of the crayfish plague the harvest of A. leptodactylus was reduced severely in most populations in Turkey after 1985. The harvest was only 320 tonnes in 1991. After the occurrence of crayfish plague in Turkey, in order to increase crayfish production uncontrolled A. leptodactylus stockings have been carried out in many waterbodies throughout Turkey. These introductions have caused an increase in the number of A. leptodactylus populations, but exploitation of A. leptodactylus is still under the pressure of the plague, although there has been a steady increase in crayfish production in recent years. The harvest increased to 2,317 tonnes in 2004. Fortunately, among those populations affected by crayfish plague, large amounts of A. leptodactylus can still be harvested from three lakes, ?znik (Bursa), E?irdir (Isparta) and Çivril (Denizli). Thus, it seems that A. leptodactylus has a degree of resistance to crayfish plague. It is therefore interesting to investigate the resistance of A. leptodactylus caught from these populations to crayfish plague.     

Seminal plasma composition and its relationship with physical spermatological parameters of Grass carp (Ctenopharyngodon idella) semen: with emphasis on sperm motility

In this research, the mineral and organic composition of the seminal plasma, physical spermatological parameters and their physiological relationships were investigated in grass carp (Ctenopharyngodon idella). The seminal plasma contained 98.14±5.23 mM L^?1 (Na⁺), 380.85±25.95 mM L^?1 (K⁺), 30.25±4.96 mg dL^?1 (Ca²⁺), 19.16±1.70 mEq L^?1 (Mg²⁺), 1.36±0.11 mg dL^?1 glucose, 0.37±0.08 g dL^?1 total protein, 12.02±1.18 mg dL^?1 cholesterol, 14.85±1.50 mg dL^?1 triglyceride and 43.5±9.56 mg dL^?1 urea. The following spermatological parameters were found: sperm volume 14.44±1.16 mL, sperm motility 80.60±1.55%, movement duration 67.68±4.32 s, density 15.43±0.72 × 10⁹ mL^?1, total density 337.43+45.86 × 10⁹ and pH 7.24±0.17. The Na⁺ and Ca²⁺ ions correlated negatively with spermatozoa motility (r=?0.453, P>0.05 and r=?0.192, P>0.05) respectively. The K⁺ ion correlated positively with spermatozoa motility (r=0.545, P>0.05). But a statistically significant correlation was not observed between sperm motility and seminal plasma parameters. The following correlations were observed between mineral and organic components. The Mg²⁺ was positively correlated with glucose and cholesterol (r=0.692, P<0.05 and r=0.680, P<0.05) respectively. A highly significant positive relationship was also found between Mg²⁺ and total protein (r=0.837, P<0.01). On the other hand, a significantly negative relationship was found between Ca²⁺ and triglyceride (r=?0.639, P<0.05). These parameters should be considered when developing procedures for either artificial fertilization or for cryopreservation of grass carp sperm.     

Cryopreservation of scaly carp (Cyprinus carpio) sperm: effect of different cryoprotectant concentrations on post-thaw motility, fertilization and hatching success of embryos

The aim of the present study was to determine the effect of various cryoprotectants on post-thaw sperm quality and fertilizing capacity of cryopreserved scaly carp (Cyprinus carpio) semen. The present study focused on freezing of scaly carp sperm utilizing a practical and inexpensive protocol for aquaculture. Semen was diluted with Kurokura’s extender composing 3.6 g/l NaCl, 10 g/l KCl, 0.22 g/l CaCl₂, 0.08 g/l MgCl₂ and 0.2 g/l NaHCO₃. The extender contained three different cryoprotectants (DMSO, DMA and egg yolk) at ratios of 5, 10 and 15 %. Semen was placed into 0.25-ml straws and exposed to liquid nitrogen vapor (?120 °C) using an insulated box with an adjustable tray for 10 min and then plunged into liquid nitrogen (?196 °C) tank. The thawing process was performed in a water bath at 40 °C for 10 s. The results indicated that type of cryoprotectants and their concentrations are rather effective in scaly carp sperm cryopreservation on post-thaw sperm quality, while they are very important in order to obtain high fertilization rates. The highest fertilization rate was determined as 96.4 ± 0.15 % with 15 % egg yolk, while the highest hatching rate was determined as 99.3 ± 0.80 with 15 % DMA. In conclusion, the applied cryopreservation method for scaly carp sperm is suitable to fertilize high amounts of eggs.     

Evaluation of ethyl methanesulfonate-induced in vitro mutagenesis,polymorphism and genomic instability in wheat (Triticum aestivum L.)

Journal of Crop Science and Biotechnology - Wheat (Triticum aestivum L.) is highly rich in nutrients and is an important staple food for humankind. Mutation breeding offers a relatively quick...     

Meat Yield,Condition Index,and Biochemical Composition of Mussels (Mytilus galloprovincialis Lamarck, 1819) in Sinop,South of the Black Sea

Monthly variations in meat yield and biochemical composition of Mediterranean mussels on lantern nets were investigated from May 2005 to May 2006, in Sinop, south of the Black Sea. Dry weight condition index was between 2.66 and 7.10% with a mean of 4.86 ± 0.36%. Meat yield was maximum (26.69%) in March and minimum (17.43%) in October. Moisture values were between 78% (in June) and 86% (in April). Protein content in dry weight of mussels reached the highest value in February (74.64%) before the spawning time. Lipid value was maximum (18.03%) in May 2005.     

The effect of Rhizobium spp. inoculation on seed quality of bean in Turkey

Rhizobium spp. (local isolate) was used to inoculate three bean (Phaseolus vulgaris L.) varieties; Akman 98, G?ynük 98 and Sehirali 90, in a factorial field experiment. The objective of the experiment was to study effect of inoculation on seed yield, protein range, seed weight, non-soaker capacity and hydration index. Rhizobium spp. inoculation and nitrogen fertilizer significantly increased characters tested. This study revealed that inoculation with Rhizobium spp. improved seed quality.     

Pathogenicity of four native isolates of entomopathogenic nematodes against Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae)

Journal of Plant Diseases and Protection - The confused flour beetle, Tribolium confusum Jacquelin du Val, 1863 (Coleoptera: Tenebrionidae) is a major pest on stored grains. Chemical pesticides are...