Morphological analysis of erythrocytes of an Antarctic teleost under heat stress: Bias of the stabling effect

The stenothermal Antarctic fish that live in the coastal waters of the Terra Nova Bay (Ross Sea) are rarely exposed to temperatures above zero during the year. We tested whether a slight temperature rise of 1.5 °C affects a sensitive biomarker such as erythrocytes morphology in sections of blood pellets of a small demersal notothen. The erythrocytes' shape descriptors showed significant or highly significant differences temporally from the capture of fish to the conclusion of the experiment. Surprisingly, the erythrocyte's morphology did not show significant differences between the two experimental conditions, returning similar results in control fish stabled at -0.9 °C and in the fish treated at +0.6 °C, although the values of the shape descriptors were often lower in the latter. This study demonstrates the critical issues of comparative physiology in the study of extremely sensitive organisms, such as the fish of the High Antarctic Zone. Moreover, the stabling effect inside the aquarium facilities appears to significantly obscure the effects of the experimental heat treatment.

Hematological and gill histopathological parameters of three tropical fish species from a polluted lagoon on the west coast of Mauritius

Gill histopathology and hematological primary indices, including blood delta-aminolevulinic acid dehydratase (deltaALA-D) activity and nucleocytoplasmic ratio of erythrocytes, were assessed in three tropical marine fish species, Scarus ghobban, Epinephelus merra, and Siganus sutor, from the presumably contaminated lagoon of Bain des Dames, Mauritius. Concurrently, the nonpolluted region of Blue Bay/Pt d'Esny was used as a reference site for comparison of fish physiological responses and seawater quality. Bain des Dames showed high seawater mercury content (6.4+/-0.5 microg/L), traces of iron (70+/-40 microg/L), and fluctuating biochemical oxygen demand values (0.488+/-0.171 mg/L day(-1)). Gill histopathological analysis revealed lesions such as epithelial hyperplasia and inflammation. Similarly, a generalized increase in blood deltaALA-D activity (131.27-355.76 nmol PBG/ml RBC.h) was recorded. Fish from Bain des Dames showed species-specific hematological responses including normocytic macrocytic blood cells (S. ghobban), macrocytic anemia (S. sutor), and active erythropoiesis (E. merra). Though the species displayed impaired health, attributed to changes in water quality, the blood responses seemingly indicate adaptation to hypoxic conditions arising from both gill degradation and perhaps oxygen-level fluctuations.

The effects of cell ageing on protein synthesis in rainbow trout (Oncorhynchus mykiss) red blood cells

The effects of cell age on protein synthesis were examined in the nucleated red blood cells of rainbow trout (Oncorhynchus mykiss). Total DNA content was unaffected by cell age, whereas total RNA content in young red blood cells was roughly ten times as high as that in old red blood cells. The mRNA levels for haemoglobin, carbonic anhydrase and the chloride/bicarbonate (Cl(−)/HCO(3)(−)) exchanger were also approximately tenfold higher in young red blood cells. Although young red blood cells synthesized roughly five times more protein under steady-state conditions, total protein concentration was not affected by cell age. Despite large reductions in mRNA levels with red blood cell ageing, the concentrations and/or activities of the respiratory proteins were largely preserved. In contrast, the ability to mount a heat shock response was greatly reduced in older red blood cells. Young red blood cells produced 13 times more heat shock protein 70 mRNA following heat shock and four times more 70 kDa protein after recovery. They also transcribed much more heat shock cognate 71 and heat shock factor mRNA than did older red blood cells under steady-state conditions.

Spectral imaging of red blood cells in experimental anemia of Cyprinus carpio

In the present work we have studied the effect of experimental anemia induced at both low and optimal temperatures on erythropoiesis in Cyprinus carpio. The results showed that hemoglobin concentration per cell was similar in both temperature conditions, however, red blood cell (RBC) concentration was higher at the optimal temperature. Induced anemia caused an abrupt decrease in RBC concentration, while the hemoglobin concentration per cell remained unchanged. Recovery, as shown by electron microscopy, was characterized by the release of differentiating young and intermediate cells to the peripheral blood. It was revealed that with the progression of differentiation the nucleus/cytoplasm ratio decreases, the chromatin condenses and the shape of the nucleus changes from round to elliptical. Spectral imaging revealed an increase in the optical density of chromatin with the maturation of the cells. The chromatin that was dispersed over the nuclear volume in the young cells becomes highly ordered in the mature cells. Spectral similarity mapping revealed the formation of a novel structure of high symmetry, representing chromatin rearrangement during the process of cellular differentiation.

Hematology and clinical chemistry of cyprinid fish. Common carp and goldfish

Evaluation of the clinical status in aquatic species is compromised by the limited diagnostic techniques that can be performed in these species. The hematologic and plasma chemistry parameters can provide predictive information, although these parameters can be highly variable owing to the influence of various intrinsic and extrinsic factors. However, these parameters are fairly stable in acclimated, well-managed fish if stress is reduced during collection and samples are properly collected and analyzed. Evaluation of any single parameter is not predictive and, therefore, not recommended. Ideally, the diagnostic protocol should include evaluation of the hematologic indices, total and differential cell counts, TPP, glucose, sodium, and chloride. The practitioner who is routinely involved in aquatic animal medicine should consider in-house evaluation of these parameters.

Hematological response in fish: pronephric and splenic involvements in the goldfish,Carassius auratus L

Pronephric and splenic involvements in erythropoiesis and in stress-induced hematological response by goldfish,Carassius auratus, were examined under conditions of minimal stress and following transient (3h) temperature-induced elevation of O2 demand and transient (3h) exposure to hypoxia. Although hemoglobin content and red cell numbers were little affected, the ontogenic composition of the circulating erythrocyte population was significantly altered by both types of respiratory challenge and also by the stresses associated with capture, air exposure during transfer and intraperitoneal administration of label. Juvenile cell numbers increased sharply while mature erythrocyte abundances declined. Consistent with this, [(3)H] methylthymidine-labeled cell numbers rose in both spleen and pronephros following imposition of stress. Splenic erythropoietic activity was modest relative to that of the pronephros. Our observations point to a readily triggered response involving: [1] release of cells reservoired in the spleen and pronephros, [2] increased erythropoiesis and [3] karyorrhexis. We suggest that while the magnitude of response may depend on the quality and magnitude of the imposed stress, its central features are essentially constant.

Erythrodynamics in fish: recovery of the goldfishCarassius auratusfrom acute anemia

Goldfish (Carassius auratus) were rendered anemic through immersion in phenylhydrazine∙HCl, a cohort of [3H]thymidine-labelled erythrocytes was established, and recovery followed over a 234-d period. Red blood cell (RBC), hemoglobin (Hb), and hematocrit (Hct) levels increased in biphasic fashion during recovery, rapid increases to plateau values being followed by more modest increases to levels equalling those observed prior to treatment. During the initial rapid phase of response, increased ventilatory and cardiovascular activities probably compensated for deficits in oxygen-carrying capacity but, by elevating blood O2tension, may have suppressed erythropoiesis. Continuing slow increases in RBC, Hb, and Hct may point to some as yet unidentified alternative mechanism for stimulating red cell formation. During maturation, mean erythrocytic volume decreased, while mean erythrocytic hemoglobin level increased. Cycles of division of circulating juvenile erythrocytes occurred at roughly 56-d intervals, but did not appear to play a major role in elevating blood O2-carrying capacity. Division and karyorrhexis or cell breakdown were loosely correlated. Under the conditions employed, red cell half-life was approximately 80 d.

Maturation of the goldfish (Carassius auratus) erythrocyte

1. Cohorts of [3H]thymidine-labelled erythrocytes were examined over a 42-day period in goldfish (Carassius auratus L.) recovering from phenylhydrazine HCl-induced anemia under normoxic conditions at 20 +/- 1 degree C and maintained with minimal disturbance on a high nutritional plane. 2. As judged by changes in primary and derived hematological variables, maturation required 16-20 days. 3. Similar estimates were obtained using cytomorphic variables obtained by image analysing methods. 4. These suggest that juvenile red cells in this species can be identified on the basis of the following characteristics: major axis less than 9.2 microM; one-sided surface area not greater than approximately 50 microns2; axis ratio greater than 0.774; form factor greater than 0.938. 5. Corresponding values for mature cells are: major axis greater than 11.2 microns; area greater than 68.5 microns2; axis ratio less than 0.716; form factor less than 0.912. 6. These criteria, with values for dividing and karyorrhectic cell numbers, offer a basis for more detailed and dynamic characterization of the erythron during response to environmental variation than has previously been possible.