Enzymatic, skeletal, and histological ontogeny of shi drum (Umbrina cirrosa) larvae under intensive culture conditions.

This study was conducted to investigate the structural and ontogenetic development of the skeletal system and digestive tract histologically and enzymatically in larvae of shi drum (U. cirrosa) under intensive rearing conditions until 40 days after hatching (DAH). Among digestive enzymes, amylase was detected at 0.89 ± 0.12 mU mg protein-1 on the first hatching day. The specific activities of trypsin and lipase were detected simultaneously with mouth opening on 3 DAH with 28.47 ± 3.52 and 2.8 ± 0.32 mU mg protein-1, respectively. In addition, pepsin was found for the first time at 0.88 ± 0.21 mU mg protein-1 on 15 DAH in association with stomach formation and increased sharply up to 40 DAH. In the structural development of the skeletal system, the development of the caudal fin in larvae was morphologically associated with the flexion of the notochord. It was observed that the shape of the fin and spine, which reached 40 DAH, became similar to the adult shape. Histologically, 3 DAH, the mouth and anus were opened. The formation of the primitive stomach was observed at the end of the seventh day-the pyloric sphincter formed between 13 and 18 days. A functional stomach was seen on the 15th DAH. Therefore, U. cirrosa is believed to have critical aquaculture potential that can be cultured under intensive conditions. The developmental profile of skeletal, enzymatic, and histological ontogeny observed in U. cirrosa is similar to that described for other sciaenid species.

Evaluation of occupational health and safety risk factors in Turkish marine fish hatcheries.

In this study, the approaches of employees in marine fish hatcheries to occupational health and safety were determined. Cronbach's α coefficient was calculated as 0.858 in the reliability of the scale and scale factors based on internal consistency. In addition,factor analysis according to the varimax method was found to be approximately 64%. It was determined that 68% of the employees were not aware of the relevant laws. In addition,85% of the employees are aware of the dangers and risks in their workplaces. In the event of a negative situation in the workplace,the rate of those who know their legal rights is 73% (p ≤ 0.05). In addition,91% of the employees stated that they would use their right to object in a risky situation and quit the job. Sixty per cent of the employees stated that their jobs can satisfy them sociologically and economically throughout their life.

In vivo and in vitro evolution of the effects of cypermethrin on turbot (Scophthalmus maximus, Linnaeus, 1758) spermatozoa.

Synthetic pyrethroid pesticide is commonly used in agricultural activities in the Black Sea region during reproduction period of turbot. In this sense, in vivo and in vitro studies have shown that cypermethrin (CYP) could be one of the environmental factors affecting decreasing turbot stocks. In this study, effects of in vivo and in vitro administration of CYP, a synthetic pyrethroid, on sperm kinematics motility (MOT), progressive motility (PM), curvilinear velocity (VCL), straight line velocity (VSL), average path velocity (VAP), linearity (LIN), straight line velocity (STR), amplitude of lateral head (ALH), beat cross frequency (BCF), oxidative stress biomarkers malondialdehyde (MDA), reduced glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and lipid peroxidation (LPO) and also histopathological alterations in gonads were investigated in spermatazoa of turbot (Schopthalmus maximus). Broodstock was supplied from culture origin and used in spawning season, additionally, two (0, 0.187 and 0.218 ppb) and three (0, 1.025, 2.05 and 4.1 ppb) different CYP concentrations were performed for in vivo and in vitro studies, respectively. In vivo and in vitro studies, significant reductions were found in sperm MOT, PM, VCL, VSL, VAP, LIN, and ALH properties depend on the increase in CYP concentrations (p < 0.05). Besides, activities of GSH, GPx, SOD, and CAT increased. In terms of histological alterations, no difference was observed among groups (0, 0.187 and 0.218 ppb) in the maturity stage of the germ cells. According to obtained results, sperm kinematics was affected significantly with increased the dose levels of CYP (p < 0.05).

Functional changes in digestive enzyme activities of meagre (Argyrosomus regius; Asso, 1801) during early ontogeny.

The ontogenesis of main pancreatic and intestinal enzymes was investigated in the recent promising Mediterranean candidate species of meagre, Argyrosomus regius, during larval development until 40 days after hatching (DAH). The green-water technique was carried out for larval rearing. Whole-body homogenates were used for enzymatic analysis in larvae younger than 15 DAH; after this date, older larvae were dissected into two segments as pancreatic and intestinal segment. Trypsin was detected as early as hatching and sharply increased concurrently with age and exogenous feeding 15 DAH, but constant decline was observed until the end of experiment. Amylase was determined at 2 DAH and sharply increased 10 DAH. Then, slight decreases were found between 10 and 15 DAH, and then slow alterations were continued until the end of the experiment. Lipase was firstly measured on day 3; then, sudden decline was observed between 20 and 25 DAH. After this date, slow fluctuations were maintained until the end of the experiment. Pepsin was firstly assayed 15 DAH related to gastric gland secretion and sharply increased 30 DAH. Then, it slowly varied until end of the experiment. Enzymes of brush border membranes, alkaline phosphatase and aminopeptidase N showed similar pattern on specific activities during the first 10 days. Thereafter, while specific activity of alkaline phosphatase slightly decreased 15 and fluctuated until 20 DAH, aminopeptidase N activity slowly increased 20 DAH. Then, activity of alkaline phosphatase and aminopeptidase N constantly increased 30 DAH, indicating maturation of the intestinal digestive process, and also, these activities continued to slowly increase until the end of the experiment. The specific activity of cytosolic peptidase, leucine-alanine peptidase, smoothly increased on day 8, then fluctuated until 15 DAH. After this date, in contrast to enzymes of brush border membranes, it sharply decreased 25 DAH and continued to gradually decline until the end of the experiment. These converse expressions were indicative of a maturation of enterocytes and the transition of an adult mode of digestion.

Ozone disinfection of eggs from gilthead seabream Sparus aurata, sea bass Dicentrarchus labrax, red porgy, and common dentex Dentex dentex.

The risk of fish pathogen transmission via eggs can be reduced by disinfection in ozonated seawater. The aim of this study was to determine the suitable conditions for ozone disinfection of the eggs of gilthead seabream Sparus aurata, sea bass Dicentrarchus labrax, red porgy Pagrus pagrus, and common dentex Dentex dentex. The eggs were disinfected with a concentration (C) of 0.5 mg of ozone/L of water at four different exposure times (T = 2, 4, 8, and 16 min). The hatching rate was determined in triplicate for each treatment. Bacterial colonies were counted on tryptic soy agar and thiosulfate-citrate-bile salts-sucrose agar. At the end of the experiment, bacterial load and hatching rate were assessed together to determine the optimal ozone treatment values, which were estimated in CT units (i.e., C [= 0.5 mg/L] x T [min]). Optimal values were CT 2-4 (T = 4-8 min; 18 degrees C) for gilthead seabream and red porgy, CT 2 (T = 4 min; 18 degrees C) for common dentex, and CT 4 (T = 8 min; 15 degrees C) for sea bass.

Organogenesis of exocrine pancreas in sharpsnout sea bream (Diplodus puntazzo) larvae: characterization of trypsin expression.

The ontogeny and differentiation stages of digestive systems related with trypsin expression in larvae of sharpsnout sea bream, Diplodus puntazzo, were investigated from hatching to 40 DAH (days after hatching), and total lengths and weights of larvae were determined. Histologic and enzymatic techniques were used to explain the functional development of the pancreas including trypsin activity. The pancreas was identified as a compact structure located in the region slightly posterior to the liver. At 3 DAH, first anus and then mouth opened. Incipient pancreas secretion polyhedral cells could be first observed as zymogen granules. During larval metamorphosis, the pancreas became diffuse, spreading throughout the mesentery in proximity to the stomach, the anterior intestine and the pyloric caeca. The specific activity of trypsin (42.54±6.8 mU/mg protein(-1)) was found as early as after hatching at larvae size of 2.87±0.34 mm at 0 DAH. Activity further increased until 10 DAH, especially after exogenous feeding. The highest trypsin activity was detected at 25 DAH as 119.26±11.6 mU/mg protein(-1). It is concluded that exocrine pancreas organogenesis is the main critical step in the development of digestive system that results in zymogen granules accumulation and increased trypsin activity.

Digestive enzyme activities in larvae of sharpsnout seabream (Diplodus puntazzo).

The ontogenesis and specific activities of pancreatic and intestinal enzymes were investigated in sharpsnout sea bream, Diplodus puntazzo, during larval development until the end of weaning on day 50. The green-water technique was carried out for larval rearing in triplicate. Trypsin was first detected as early as hatching and sharply increased related to age and exogenous feeding until day 25, but a sharp decrease was observed towards the end of the experiment. Amylase was determined 2 days after hatching (DAH) and sharply increased to 10 DAH. Afterwards, slight decreases were found between 10 and 20 DAH and then slow alterations were continued until end of the experiment. Lipase was measured for the first time on day 4, and then slight increase was found to 25 DAH. After this date, slow variations were maintained until end of the experiment. Pepsin was firstly assayed 32 DAH related with stomach formation and sharply increased to 40 DAH. Then it was fluctuated until end of the experiment. Enzymes of brush border membranes, alkaline phosphatase and aminopeptidase N, showed similar pattern on specific activities during the first 10 days. Thereafter, while specific activity of alkaline phosphatase slightly decreased to 15 DAH and fluctuated until 20 DAH, aminopeptidase N activity slowly declined to 20 DAH. Afterwards, activity of alkaline phosphatase and aminopeptidase N were sharply increased to 30 DAH, showing maturation of the intestinal digestive process and also these activities continued to slight increase until end of the experiment. The specific activity of cytosolic peptidase, leucine-alanine peptidase sharply increased to on day 8, then suddenly declined to 12 DAH and further decreased until 20 DAH. After this date, in contrast to enzymes of brush border membranes, it sharply decreased to 25 DAH and continued to gradually decline until the end of the experiment. These converse expressions were indicative of a maturation of enterocytes and the transition to an adult mode of digestion.