AQUATIC ANIMAL REPORTS (AQAR)

Determination the changes of E. coli depuration times in Ruditapes decussatus and Venus verrucosa by production area and species differences

İbrahim Ender Künili — 2024-02-21

In this study, two important economic bivalve mollusc species, grooved carpet shell (Ruditapes decussatus) obtained from two different production areas (batch-A and batch-B) and warty venus (Venus verrucosa) were contaminated with Escherichia coli (E. coli), and the time-dependent changes in their ability to depuration process were determined. At the same time, after the natural E. coli levels of these two species were determined, the natural depuration times were also investigated by subjecting them directly to depuration process separately.

The natural E. coli loads of the carpet shell and warty venus samples used in the research were determined as 1500 MPN/100 g in batch-A samples, 430 MPN/100 g in batch-B samples while the level was determined as 74 MPN/100 g warty venus samples. The natural sample depuration process was completed 18 hours after the start of the process for batch-A samples and 6 hours after the start of the process for batch-B and warty venus samples, and it was determined that the products reached Class A production area standards. Depuration time of samples after the contamination of samples with E. coli at the level of 2900 MPN was determined as 12 hours for warty venus, 18 hours for carpet shell. As for the samples contaminated at the level of 4600 MPN, carpet shell (batch-A) and warty venus samples reached the Class A production area standards after 24 hours and warty venus (batch-B) samples reached the Class A production area standard after 48 hours. As a conclusion, species, and sample collection sites may have effect on depuration characteristics of E. coli and this may be related to physiological conditions of the specimens during the collection sites.

Effects of Adding Garlic, Thyme And Sage Powder and Oil to Juvenil Trout Feed

Önder Toprak Ergül — 2024-02-21

In this study, powder (5%) and oil (1%) forms of medicinal and aromatic plants sage (Sage officinalis), thyme (Origanum onites) and garlic (Allium sativum) were added to the feed of juvenile rainbow trout (Oncorhynchus mykiss W.) to improve growth performance and performance. In this study, powder and oil forms of garlic, thyme and sage were tested and their antioxidant enzyme activity and growth values were determined. For this purpose, 5% (0.05 mg/kg) of the powder forms of sage, thyme and garlic and 1% (0.01 mg/kg) of the oil forms of the same products were added to the trial feeds. Fish weigh an average of 17 grams. It was tested in spring water with its physicochemical properties for 80 days (water temperature; 8ºC, dissolved oxygen 9.6 ppm. pH: 6.5). In the study; Live weight gain (41.32±2.47), specific growth rate (3.72±0.47), and feed conversion rate (1.04±0.097) were best obtained in the SY group (p<0.05). Among the antioxidant enzyme activities, malondialdehyde (MDA) was insignificant between the groups (p>0.05), while catalase activity was best in the thyme group, and superoxide dismutase (SOD) was best in the garlic groups (p<0.05).

Distribution of Sphaeriidae (Mollusca: Bivalvia) in relation to environmental variables in Northwestern Basin Streams in Türkiye

Deniz Anıl ODABAŞI — 2024-02-21

In this study, Sphaeriidae family was investigated in some freshwater systems of northwestern basin streams of Türkiye such as Karamenderes, Sarıçay, Mıhlı and Tuzla with respect to environmental variables. A standard multi-habitat sampling technique was applied to these streams at pre-selected stations using kick-net and surber-net. In addition, some water quality parameters such as temperature, pH, dissolved oxygen, conductivity, Oxidation Reduction Potential (ORP) were measured in situ using a multimeter probe. The taxa of Sphaeriidae were identified and counted in the laboratory under stereo microscope. The identified taxa were as follows, Musculium lacustre, Pisidium casertanum, P. nitidum, P. subtruncatum and P. sogdianum. Three of these species, namely P. casertanum, P. subtruncatum, P. nitidum, were widely distributed in the study area, while the rest were found in narrow ranges, especially P. sogdianum, which was found only in the Tuzla stream. The individual numbers of species in some streams were subjected to multidimensional scaling using SPSS 21.0. According to the multi-dimensional scaling (MDS), most of the water quality parameters influenced the distribution of most of the species. Water conductivity is the least effective parameter among the measured parameters, additionally P. casertanum and P. sogdianum showed distribution independent of water quality parameters.

Isolation of early stage testicular germ cells of rainbow trout by percoll gradient centrifugal method

Sude Atmaca — 2024-02-21

The purpose of this study was to isolate germ cells from rainbow trout (Oncorhynchus mykiss) testicular tissue by employing a percoll gradient centrifugation method. Therefore; testicular tissue samples from rainbow trout were incubated with 0.5% trypsin (2 h, 20°C) in phosphate-buffered saline (PBS) solution for enzymatic separation. Gradient centrifugation method was performed using percoll at different rates (45% - 10%, 50% - 10% and 55% - 10%). Following centrifugation, three layers were formed. In the uppermost layer, debris and spermatids; early stage germ cells in the middle layer and a small amount of spermatids; and in the pellet located in the bottom layer, erythrocytes and spermatids were detected intensively. In addition; both histological and immunofluorescence methods were utilized to identify testicular and somatic cells. Hematoxylin-eosin staining of histological sections from testicular tissue revealed spermatogonia types A and B, and spermatid cells. Fluorescent staining of tissue sections revealed early stage germ cells labeled with primary antibody (DDX4) and the secondary antibody (FITC).

Microalgae Applications in Aquaculture

Tolga Göksan — 2024-02-21

Microalgae are at the base of the aquatic food chain, even of the life on our planet, and able to accumulate unique molecules for all livings. These microorganisms, which are mostly photosynthetic, are rich source of essential and functional nutrients such as amino acids, polysaccharides, polyunsaturated fatty acids (PUFAs), minerals, vitamins etc. In the last decades, the use of the whole microalgae biomass and microalgae-derived compounds as food supplements has increased. However, the role of microalgae in aquatic ecosystems, especially in aquaculture, is crucial and irreplaceable since they are the essential part of the system and the primary producers. This article aimed to review the favourable effects of using microalgae in aquaculture.