Agata Kowalska

The purpose of this study was to compare four activation solutions (AS)—Woynarovich, Lahnsteiner, Kucharczyk, and Perchec—with the addition of 0.5% bovine serum albumin (BSA) for ide (Leuciscus idus) sperm activation and analysis with a CASA system. It was found that ide sperm can be activated using each AS within a pH range of 7.4–9.0 and an osmolality range of 160–200 mOsm kg⁻¹. The effect of Woynarovich and Perchec solutions supplemented with BSA and casein at concentrations of 0.25, 0.5, 1.0, and 2.0% were also analyzed during the experiment. These two AS without protein supplementation (pure solutions) were the controls. Woynarovich and Perchec solutions supplemented with the minimum BSA concentration (i.e., 0.25%) significantly improved sperm motility (89.05% and 86.63%, respectively) compared to the controls (20.39 and 28.48%, respectively). Similar increases were also noted in progressively motile sperm (PRG, %), the curvilinear velocity of sperm (VCL, µm s⁻¹), and the amplitude of lateral head displacement (ALH, µm). A similar trend in CASA parameters was also noted when casein was added to Woynarovich and Perchec solutions at a concentration of 0.25%. We concluded that 0.25% doses of each of the proteins were sufficient to prevent sperm adhesion to glass slides, and they can be used in research on ide sperm motility measurements.

A 3-week feeding trial was conducted in medaka broodstock (age five months) to examine the effect of dietary arachidonic acid (ARA) level (range: 4–23 mg g⁻¹ of total fatty acids (TFAs)) on fertility, cyclooxygenase (COX) activity, egg size, sperm motility parameters, hatching rate and weight of hatch, survival and growth of larvae. After spawn induction and dietary exposure to 4 mg ARA g⁻¹ TFA, broodstock were fed a diet containing ARA in the amounts: 4 (continued, as control), 5, 14 and 23 mg g⁻¹ TFA. COX1 activity in the liver and the number of COX2-positive cells in the ovaries was increased in females fed the diets containing the two highest amounts of ARA. The highest sperm motility parameters were observed in males fed a diet containing 23 mg ARA g⁻¹ TFA. The hatchability rate and bodyweight of hatchlings were higher in the group obtained from broodstock fed a diet containing 23 mg ARA g⁻¹ TFA (79% and 0.66 mg fish⁻¹, respectively) compared with 4 mg ARA g⁻¹ TFA (50% and 0.40 mg fish⁻¹). The average mortality of offspring obtained from this group at 7 days post hatching was significantly higher than that of all other groups.

The effect of dietary resveratrol (40 µg g ⁻¹ BW day ⁻¹ ) on cell-mediated immunity (the activity of spleen phagocytes and the proliferative response of lymphocytes) and liver histology (hepatocyte morphometry, lipid vacuoles, and glycogen granules) in adult medaka ( Oryzias latipes ) (aged two years, body weight BW = 0.49 g) were tested after ten days of feeding with experimental diets. The fish were fed either a commercial diet (control group C) or this same diet supplemented with resveratrol (group R) three times daily at 3% of body weight (BW). Fish fed feed with resveratrol had significantly higher intracellular phagocyte killing activity than did those in the control group (P < 0.05). No differences in the sizes of hepatocytes or their nuclei were observed in the fish from groups C and R. The nucleo-cytoplasmic ratio ranged from 0.39 (± 0.03; group R) to 0.42 (± 0.03, group C) in adult medaka exposed to the two dietary treatments (P > 0.05). The results indicated that the diet supplemented with resveratrol at a dose of 40 µg g ⁻¹ BW day ⁻¹ had no impact on the liver tissues. Typical hepatocytes with lipids and glycogen were observed to the same extent in the vacuoles. Moreover, no mortality or pathological changes were noted in the fish studied. The diet containing resveratrol helped to maintain disease resistance without affecting the liver tissue after ten days of feeding.

Effective Microorganisms (EM) technology uses microorganisms to work in the surrounding environment. Complex microbiological preparations show synergistic effects, combining the effects of probiotics, prebiotics and synbiotics. EMTM technology is well-known and used in 120 countries worldwide, mainly in agriculture, including aquaculture, and in environmental protection. Fish farmers use these preparations to enhance fish growth, condition and immunity. The aim of the study was to evaluate the effect of EM-Probiotic (Greenland) on the development of cellular non-specific resistance in pikeperch (Sander lucioperca) at the initial stage of rearing in a recirculating aquaculture system (RAS). The experimental diet was administered for 28 days with EM supplementation at 0% (control group), 2% and 4% of the feed. Water temperature in the RAS was maintained at 22.0ºC. Hematopoietic organs (spleen and kidney) were collected twice, after 28 days of EM supplementation (first term) and 28 days after cessation of supplementation (second term). The respiratory burst activity (RBA) and potential killing activity (PKA) of macrophages, as well as the proliferative activity of T- and B-lymphocytes (MTT assay) were assessed. The results of the study show that EM at the initial stage of pikeperch development (body weight of 2 to 14 g) suppress cellular defence mechanisms, decreasing the activity of immunocompetent cells in RBA, PKA and MTT tests. The results from the first organ harvesting showed differentiated EM activity at a statistically insignificant level (P>0.05). In samples collected 28 days later, the inhibitory effect was demonstrated at a statistically significant level (P<0.05) in all parameters in both experimental groups. Non-specific cellular immunity in fish plays a key role in defence against damaging factors, including pathogenic ones. Since fish in an RAS are also susceptible to potentially pathogenic agents, immunosuppression of these mechanisms may aggravate the disease..

The aim of this work was to determine the impact of etomidate (Propiscin) dose (1 and 2 ml l⁻¹) and exposure time (2 and 10 min) on the biochemical and haematological parameters of juvenile pikeperch (Sander lucioperca) [mean body length (Lc) 25.9 cm; body weight (W) 189.9 g] that were reared in a recirculating aquaculture system (RAS). Significant changes in the mean values of total protein, globulin, calcium, magnesium, and ammonia were noted in all groups immediately following exposure. The greatest changes in the haematological indicators were observed in groups subjected to 10-min exposure at both doses of the anaesthetic. The specimens from these groups had higher values for white blood cells (WBC), red blood cells (RBC), haemoglobin (HGB), haematocrit (HCT), and mean corpuscular volume (MCV). Statistically significant differences in these same parameters were also noted in the groups of fish exposed to the anaesthetic for 2 min at a dose of 2 ml l⁻¹, but they were not as pronounced. Twenty-four h following exposure to etomidate, all blood parameters in the experimental groups were comparable to those of the control group. Etomidate can be recommended as a safe, effective anaesthetic for pikeperch.

Here, we investigated the effect of dietary resveratrol (20, 40, and 80 µg/g BW/day) on cell-mediated immunity (activity of spleen phagocytes and proliferative response of lymphocytes) and reproductive parameters (egg and sperm quality, i.e. fecundity—total number of eggs produced by individual fish, fertility, embryo survival, and hatching rate) in medaka. Fish fed feed with resveratrol at 40 and 80 µg/g BW/day had significantly higher metabolic activity and intracellular phagocyte killing activity than control. The proliferative lymphocyte activity of the fish from R80 group was greater by more than 20 % in comparison with the control group (P < 0.05). The percentage of macrophages (MO) and their mean fluorescence intensities (MFI) in R40 and R80 groups were significantly higher compared to C and R20 groups (P < 0.05). The differences in MO and MFI values ranged from 52.5 % (±1.5; R0 group) to 65.8 % (±1.6; R80 group) and from 23.2 (±1.4; R0 group) to 38.2 (±2.4; R80 group), respectively. Moreover, resveratrol at 80 µg/g BW/day decreased liver COX activity, i.e. 5.4 in R80 group and 7.9 in R0 group (P < 0.05). The motility parameters of the sperm obtained from the males fed feed supplemented with resveratrol at 80 µg/g BW/day exhibited the highest values except the linearity, which was lower as compared to the control (P < 0.05). The results indicate that diet supplemented with resveratrol at a dosage of 40 µg/g BW/day improves phagocyte killing ability and lymphocyte proliferation in broodstock and accelerates offspring hatch. Also, the results suggest that COX activity influences sperm and oocyte quality in fish; the presence of a COX inhibitor in the dose of 40 µg/g BW/day decreased the embryo survival.

Open Access Agricultural Journals published by Institute of Agricultural Economics and Information

This study showed differences in the occurrence of blood cell alteration in triploid brook trout. The triploidisation was induced by hydrostatic shock pressure at 9500 psi for 5 min at different times after fertilisation (22.5, 27.5, 32.5, 37.5, 42.5, 47, 5, 52.5 and 62.5 min). The pressure shocks at 32.5 and 37.5 min after fertilisation caused the lowest share of pathologically altered blood cells in triploid fish.