The effect of ethanol on some hematological parameters of the australian red claw crayfish (Cherax quadricarinatus)

Purpose: to study the effect of ethanol on the parameters of THC, the percentage of granulocytes and total protein in the hemolymph of the Red claw crayfish (Cherax quadricarinatus).Materials and methods. The object of this experiment was 26 males of the Australian red-clawed crayfish (Cherax quadricarinatus) weighing from 23 to 83 g. The individuals were evenly divided into two experimental groups - with an injection of ethanol and a control group without an injection of 13 crayfish for each group. The injection dose was 2515 mg per 100 g of body weight. A day after the introduction of ethanol, hemolymph was taken with a syringe from the ventral sinus, the syringe was pre-washed with a 4% EDTA-Na2 solution. Three parameters were determined: the total hemocyte count (THC), percent granulocytes and percent total protein content. Counting of hemocytes and determination of granulocytes were performed in a Goryaev chamber under a light microscope. The total protein was determined by the refractometric method.Results. Differences in THC and total protein between the groups were statistically unreliable (p>0,05). THC in the experimental group is 36% more than in the control group. The total protein after the introduction of ethanol actually increased by 0,7%, and relatively by 14%. There were statistically different indicators of the proportion of granulocytes (p<0,05) - the average value of 33,1% in the experimental group versus 24,5% in the control group. A reliable (p<0,05) strong feedback was revealed between the total protein and the mass of individuals in both experimental groups, while in the experimental group there is a visible shift in the values of dependent hemolymph indicators towards an increase in smaller individuals.Conclusion. A single injection of ethyl alcohol with a dosage of 2515 mg per 100 g of body weight into the hemolymph of C. quadricarinatus does not cause significant changes in the THC and total protein after 24 hours. At the same time, the proportion of granulocytes actually increases by 9%, relative to 37%. This may indicate that granulocytes are involved in the formation of cancer defense mechanisms when exposed to toxic substances. The effect of different dosages of ethanol injections and the duration of its effect on hematological parameters requires additional consideration. It is necessary to investigate its effect on other indicators, such as the pH and buffer capacity of the hemolymph, the concentration of hemocyanin, glucose, lactates and calcium.

Bioindicators of the constants of homeostasis of the internal environment of crustaceans, cultured in different environmental conditions for the purpose of obtaining commodity products

The study of the composition and properties of the internal environment (hemolymph) of crustaceans grown in various conditions has an important ecological and physiological aspect, since a number of characteristics of the physiological status of objects can be used to assess the state of the environment, thus, they can be included in the number of bioindicators. However, the nature of the observed differences between objects grown under different conditions, the features of homeostatic regulatory mechanisms and the limits of the reference values of individual homeostasis constants are often not known. To formulate recommendations regarding the technological process of growing objects of warm-water aquaculture, taking into account the assessment of environmental conditions in dynamics through the analysis of indicators of the state of individuals — bioindicators — it is necessary to compare the state of individuals kept in different conditions. The object of the study was the Australian red claw crayfish Cherax quadricarinatus (Von Martens, 1868), cultivated under various conditions of intensive and semi-intensive cultivation. The studies have revealed that throughout the entire period of cultivation, individuals grown in ponds retained a high level of total protein, cholesterol and β-lipoproteins, in contrast to crayfish cultivated in pools. The values of these indicators as bioindicators indicate a high degree of compliance of the growing conditions with the needs of the studied object. Comparative assessment of fluctuations in the ratio of hemolymph shaped elements in the hemocyte composition between cancers grown under different conditions did not reveal significant differences. It was found that significantly higher growth rates are characteristic of crayfish grown in ponds, in contrast to the group of individuals cultivated in pools. The comparative analysis of bioindicators in different growing conditions presented by the authors of the article supplements information that is of significant interest for monitoring the growing conditions of this representative of warm water aquaculture, which will be valuable for specialists engaged in crustacean breeding.

Detection of Infectious Hypodermal and Hematopoietic Necrosis Virus (IHHNV, Decapod Penstylhamaparvovirus 1) in Commodity Red Claw Crayfish (Cherax quadricarinatus) Imported into South Korea

Freshwater crayfish, which are cultivated in aquaculture, are economically important for food and ornamental purposes. However, relatively few studies have focused on potentially pathogenic viruses in crayfish compared to in penaeid shrimp. Commodity red claw crayfish (Cherax quadricarinatus; 400 crayfish in 10 batches) and red swamp crayfish (Procambarus clarkii; 40 crayfish in 2 batches) imported into South Korea from Indonesia and China were screened by PCR to detect infectious hypodermal and hematopoietic necrosis virus (IHHNV or Decapod penstylhamaparvovirus 1). IHHNV was detected in tissue samples pooled from nine out of ten batches of red claw crayfish imported from Indonesia. Phylogenetic analysis of PCR amplicons from representative pools clustered the IHHNV strain with infectious-type II sequences commonly detected in Southeast Asian countries rather than with type III strains detected previously in whiteleg shrimp (Penaeus vannamei) cultured in South Korea. IHHNV DNA was detected most frequently in the muscle (eight batches, 66.7% samples), followed by in the hepatopancreas (five batches, 41.7% samples) and gills tissue (three batches, 25.0% samples). These data suggest that red claw crayfish could be a potential carrier of the virus and that quarantine procedures must be strengthened in South Korea to avoid importing infectious types of IHHNV in commodity crustaceans such as red claw crayfish.