A Study on Some Biological Parameters of Crayfish (Astacus leptodactylus Eschscholtz, 1823) in Ulugöl, Samsun, Turkey

The study aimed to investigate some morphometric traits, length-weight relationship, meat yield, fecundity and some biochemical compositions of Astacus leptodactylus, in one of the Bafra Fish Lakes named Ulugöl, Samsun, Turkey. A total of 378 A. leptodactylus (198 female and 180 male) were examined. The average carapace length was 50.96±0.46 mm for females, 51.31±0.66 mm for males and 51.13±0.40 mm for all sampled crayfish. Abdomen length was 52.36±0.49 mm for females, 49.26±0.62 mm for males and 50.87±0.40 mm for all sampled crayfish. Live weight was between 14.38 g and 105.03 g with an average of 38.26±0.73 g. The average weight of females was less than that of males. There was a strong relationship between length and weight. The weight of crayfish with pleopodal eggs ranged from 28.24 g, to 59.50 g with an average of 41.73±1.09g. The average number of eggs per individuals was 192.90±9.94 with an average number of 4.62±0.21 per unit of live weight. The average total egg weight was 3.35±0.19 g while the average egg diameter was 2.17±0.03 mm. Abdomen meat was lower for males comparing with females. Average moisture, crude ash, crude oil and crude protein of abdomen meat were 81.27%, 1.47%, 0.81% and 16.45%, respectively.

Acute Toxicity of Insecticide Thiamethoxam to Crayfish (Astacus leptodactylus): Alterations in Oxidative Stress Markers, ATPases and Cholinesterase

Thiamethoxam (Thmx) is a globally used neonicotinoid pesticide contaminated in freshwater ecosystems with residues detected in fishery products. Astacus leptodactylus is a popular freshwater crustacean that is cultivated and exported in many countries. In this study, we investigated the acute toxic effects of Thmx on A. leptodactylus using various biomarkers (acetylcholinesterase, carboxylesterase, glutathione S-transferase, glutathione, superoxide dismutase, glutathione peroxidase, glutathione reductase, and adenosinetriphosphatases). The 96-h LC50 value of Thmx was calculated as 8.95 mg active ingredient L–1. As the dose of Thmx increased, oxidative stress was induced by the inhibition/activation of antioxidant enzymes, while the activities of acetylcholinesterase, carboxylesterase and adenosinetriphosphatases were inhibited. As a result, it can be said that Thmx has highly toxic effects on crayfish, therefore they are under threat in the areas where this pesticide is used.

HEMATOLOGICAL AND BIOCHEMICAL INDICATORS OF AUSTRALIAN RED-CLAW CRAYFISH HEMOLYMPH

The article describes Australian red claw crayfish, Cherax quadricarinatus, which is currently one of the most promising cultivation targets. However, to increase production volumes, it is necessary to improve cultivation technologies, which should be based on the data of physiological and biochemical parameters. An objective method for monitoring the physiological state of Australian red claw crayfish in the artificial conditions is determining its hematological and biochemical indicators that complement the general characteristics of hemolymph and later define its physiological norm. When giving the objects the compound feed, which the authors produced by their own recipe, there was recorded a high level of total hemolymph protein of 40.8 ± 4.5 g/l. According to the results of biochemical research, the cholesterol content in the hemolymph of Australian crayfish was 3.2 ± 0.6 mmol/l, and the concentration of lipoproteins was 0.8 ± 0.2 g/l (levels within the reference values). When considering the hemogram of hemolymph there were found the dominant types and linear dimensions of native formed elements. The diameter of agranulocytes in Australian freshwater crayfish varied from 85 to 90 μm, semi-granulocytes - from 90 to 95 μm, granulocytes - from 65 to 78 μm, transparent cells differed by greater variability in size, which ranged from 85 to 120 μm. The part of granulocytes in relation to other shaped elements exceeded 50%, for transparent cells it turned out to be above 20%, for semi-granulocytes - about 15% and for agranulocytes - about 5%, which means that the latter form the rarest group. The established ratios are specific for Cherax quadricarinatus, its hemocytic characteristics greatly differs from Astacus leptodactylus, which is the main object of comparative research. The results of comparative analysis of the cellular composition of the hemolymph of the Australian freshwater crayfish Cherax quadricarinatus (Von Martens, 1868) demonstrate the taxonomic specificity of this representative of freshwater aquaculture

Trace metal toxicity in some food items in three major markets in Ado-Odo/Ota LGA, Ogun State, Nigeria and associated health implications

Background: Many of the markets in Nigeria are open, where foodstuffs are laid bare on flat trays and open baskets, direct- ly exposing them to environmental contaminants. This study aimed at determining whether some food items on sale around an industrialized area of Ogun State are contaminated with trace metals. Methods: Seven different food items – Clarias gariepinus (roasted, fresh and smoked) Bos taurus (dried and fresh beef), zobo leaf (Hibiscus sabdariffa) and crayfish (Astacus leptodactylus) were sampled from three major markets, namely: Lusada, Atan and Ota in Ado-Odo/Ota LGA of Ogun State. They were analyzed for Lead, Cadmium, Nickel, Manganese and Zinc using Atomic Absorption Spectroscopy. Results: Cd was not detected in most of the food items across the markets. Pb, Ni and Mn were detected in very high con- centrations above the maximum allowable limits by international regulatory agencies. Zn was the only metal that was gen- erally below regulatory limits in food items across the three markets. The Estimated Daily Intake (EDI) and Target Hazard Quotient (THQ) values were generally higher than values acceptable in food. Conclusion: Some of the food items consumed in this area are not entirely safe from metal toxicity and this may have se- rious health consequences. Keywords: Cadmium; food items; lead; Manganese; nickel; zinc.