Haematological and haematopoietic response to sodium chloride stress in a freshwater air-breathing fish Channapunctatus Bloch

Results of experiments to determine the sensitivity of Channa punciatus to different levels of sodium chloride (NaCl) (1.2, 3.2 and 6.2g 1⁻¹) are reported. It was found that C. punctatus which is otherwise considered a hardy fish is more sensitive to higher levels of sodium chloride stress. Thus 10% of the LC50 96 h value (1.2 g 1⁻¹ NaCl) was found stressful as evidenced by loss in body weight, while 25 and 50% of the LC50 96 h value (3.2 and 6.2 g 1⁻¹ NaCl) even resulted in mortality. Haematological and associated haematopoietic investigation confirmed stress symptoms in all the parameters tested. Thus microcytic hypochromic anemia together with leucopenia was indicated at the two higher sublethal levels, i.e., 25% and 50% of LC50 96 h value. Differential leucocyte count showed that leucopenia is mainly contributed by thrombocytic and neutrophilic decrease. Other cell types, viz., eosinophils, basophils, large and small lymphocytes, showed a relatively significant (P < 0.01) increase in number.
Haematopoietic studies revealed that the two penultimate stages in both RBC and neutrophil development closely follow the trend of their counterparts in the peripheral blood. However, the stem cells of both these cell types recorded significant increase under sodium chloride stress, which indicated homeostatic response. Biochemical studies revealed a depletion in blood glucose level as well as in liver and muscle glycogen reserves.
Restoration to normal control conditions after 6 weeks of exposure to different levels of sodium chloride stress resulted in a cessation of mortality (if any), gain in body weight and more or less normality in all the haematological parameters within a period of 2 weeks.     

Haematological and haematopoietic studies in pyridoxine deficient fish, Channa punctatus Bloch

Pyridoxine deficiency was induced in a population of Channa punctatus. The deficiency effects were increased by adding 4-deoxypyridoxine as an antagonist. Haematological and haematopoietic changes were studied. The significant changes in peripheral blood appeared after 150 days in the antagonist treated group and 180 days in the group on the deficient diet. After 240 days when morphological changes and an increased mortality also appeared, the changes in RBC and related values (haemoglobin, haematocrit, MCV, MCH & MCHC) were highly significant and indicated hypochromic microcytic anaemia; this was accompanied by leukopenia. The haematopoietic studies revealed significant increase in the earlier stages of erythrocytic development (basophilic erythroblasts and polychromatophilic eryth-roblasts) with a simultaneous decrease in the later stages (young and mature reticulocytes). A series of pathological disorders in the various developing cells were recorded in the imprints of haematopoietic tissues. The pyridoxine specificity of these changes were confirmed by remedial treatment for a month.     

Haematological and haematopoietic responses to starvation in an air-breathing fish Channapunctatus Bloch

Changes in haematological values (RBC numbers, haemoglobin content, haematocrit value, MCV, MCH, MCHC, TLC and DLC) based on weekly samples from a group of starved fish were investigated. After 8 weeks of starvation, the effects of restoration to a normal diet was evaluated. Parallel studies on haematopoietic tissues were also made. Changes in some biochemical values such as blood glucose, liver and muscle glycogen were also examined to correlate biochemical effects with those of haematological changes. Erythrocytes, thrombocytes and neutrophils were found to be most sensitive to starvation. The initial response to deprivation of food was an increase in RBCs and related values and in total leukocyte population. However, from week 5 onwards a sharp decline in these cell populations was noted. The leukocytes and thrombocytes showed a change parallel to RBC and the total leukocyte counts. However, neutrophils were observed to show a consistent increase throughout the starvation period. A blood glucose level below SOmglOOmh¹ appeared critical in relation to blood cell population. Haematopoietic studies revealed that reticulocytes and mesomyelocytes were unable to keep pace with the changing peripheral blood picture. Other stages in development responded to the changes in the peripheral blood.     

Seasonal variations in the blood constituents of an air-breathing fish, Channa punctatus Bloch

A year long study based on monthly observations on the haematology of female Channa punctatus with respect to haemoglobin, haematocrit values, total erythrocyte and leucocyte numbers together with a differential enumeration of various leucocytes viz. thrombocytes small and large lymphocytes, monocytes, neutrophils, eosinophils and basophils is recorded. The study showed that the total erythrocytic number, haemoglobin and haematocrit values decrease during the breeding time i.e. July to September. The thrombocyte number significantly increased while the neutrophilic number showed a decrease. The physiological significance of these changes is discussed with reference to the available literature.     

Seasonal variation of ammonia-quotient in an Indian air-breathing freshwater teleost, Channa punctatus

The ammonia-quotient, calculated from the data on the levels of ammonia excreted and oxygen consumed from the water, is a potent tool for understanding the utilization of macromolecules as metabolic fuel. The fish, Channa punctatus, utilizes more protein in the summer and spawning months for getting its metabolic energy but in the winter and post-spawning months it also utilizes other substrates like lipid and carbohydrate for its metabolic energy.     

Cell types in the peripheral blood of an air-breathing fish Channa punctatus

Different cell types found in the peripheral blood of Channa punctatus , an air-breathing freshwater fish have been characterized and identified using morphological, morphometric, cytochemical and autoradiographic techniques. Some of the cytochemical methods used, particularly that of differential staining of haemoglobin have been developed and used for the first time in fishes.     

Seasonal reorganization of nitrogen metabolism in an Indian air-breathing teleosts,Channa punctatus (Bloch)

Channa punctatus, an air-breathing freshwater teleost, mobilizes more protein for its energy requirement during summer and spawning months, as revealed by the data on endogenous nitrogen excretion in the form of ammonia-N, urea-N, free amino acids, creatinine and creatine.     

Effect of ammonia-stress on the total autolytic levels of proteins in tissues of an air-breathing fish,Channa punctatus (Bloch)

G season-specific effect of a sub-lethal ambient ammonium chloride concentration on the total autolysis of protein in different tissues of the Indian air-breathing murrel,Chauna punctatos (Bloch), has been demonstrated. While its effect on the autotytie levels of protein of different tissues (except white muscle) was marginal in the winter-adapted fish, the same in the summer-adapted fish was more pronounced. In general a reduction in the autolysic levels of the tissue protein of the ammonium chloride-stressed fish was observed. In certain tissues like white muscle of an ammonium chloride-stressed fish and gill of the ammonium hydroxide-stressed fish, augmented levels of autolysis were noticed. The present findings suggest that the accumulation of amino acids in different tissues of the ammonia-stressed fish, as observed earlier, can be explained best by mechanisms other than ammonia induced increased breakdown of proteins.     

Modulatory effect of copper on nonenzymatic antioxidants in freshwater fish Channa punctatus (Bloch.)

Effect of the low level of copper exposure on nonenzymatic antioxidants was studied in a freshwater fish Channa punctatus (Bloch.). Fish were exposed to cupric chloride at the concentration of 10 ppb for 4 wk (28 d) in a static culture condition. Copper significantly (p < 0.001) increased the serum ceruloplasmin level and total iron-binding capacity. A significant (p < 0.05) increase in reduced glutathione level was recorded in all of the tissues. With regard to nonprotein thiols, copper decreased their level in the liver, but increased it in the gill. The protein-bound thiols remained unaltered except for an increase in the liver. Metallothionein (MT) induction was observed in liver only. Copper exposure had no significant effect on the ascorbic acid level and induced no lipid peroxidation over control values. It is suggested that by modulating the ceruloplasmin level, copper indirectly protects the fish, as it facilitates conversion of pro-oxidant iron to nonoxidant iron. It also induces an array of antioxidants that may be beneficial to fish in the case of oxidative stress resulting from chemical pollutants.     

Resistance to oxidative stress in a freshwater fish Channa punctatus after exposure to inorganic arsenic

The biochemical toxicity of arsenic trioxide (As^III) in a freshwater edible fish Channa punctatus has been studied on exposures ranging from 7 to 90 d. The arsenic concentration increased exponentially in liver, kidney, gills, and muscles of fish up to 60 d of exposure to arsenic. However, arsenic concentration in these tissues declined at 90 d of exposure. This relationship between period of exposure and concentration of arsenic in selected tissues suggests an adaptive response of fish to arsenic. Furthermore, exposure to arsenic-induced lipid peroxidation in these organs increased initially at 7 d of exposure; however, it decreased up to 60 d of exposure but increased again at 90 d of treatment. Values of reduced glutathione (GSH) reflected the observations of lipid peroxidation. The role of GSH in this adaptive response has been discussed.     

Profenofos induced DNA damage in freshwater fish, Channa punctatus (Bloch) using alkaline single cell gel electrophoresis

The aim of the present study was to evaluate the induced genotoxicity (DNA damage) due to organophosphate pesticide profenofos (PFF) in gill cells of freshwater fish Channa punctatus using single cell gel electrophoresis (SCGE)/Comet assay. The 96h LC(50) value of PFF (50% EC) was estimated for the fish species in a semistatic system and then three sub-lethal of LC(50) concentrations viz the sub-lethal 1, sub-lethal 2 and sub-lethal 3 concentrations were determined as 0.58ppb, 1.16ppb and 1.74ppb, respectively. The fish specimens were exposed to these concentrations of the pesticide and the gill tissue samplings were done on 24h, 48h, 72h and 96h post exposure for assessment of DNA damage in terms of percentage of DNA in comet tails. In general, a concentration dependent response was observed in the gill cells with induction of maximum DNA damage at the highest concentration of PFF. The results of the present investigation indicated that PFF could potentially induce genotoxic effect in fish, even in sub-lethal concentrations and SCGE as a sensitive and reliable tool for in vivo assessment of DNA damage caused by the genotoxic agents.     

An autoradioraphic and cytochemical study of erythropoiesis in a fresh water fish, Channa punctatus Bloch

Using spleen and head kidney imprints, studies on erythropoiesis in Channa punctalus have been made describing each developmental stage with regard to its morphology, morpho-metry and cytochemistry. This has been undertaken using the new techniques available for haematopoietic studies of fishes. These include autoradiography for information on DNA synthesis and Graham-Knoll's benzidine method with Giemsa used as a counterstain for the differential staining of haemoglobin. Thus, a more definitive picture of the haematopoietic phenomenon in Channa punctatus has been evolved.     

Origin and Development of Neutrophils in an Air Breathing Fish,Channa punctatus Bloch

Mahajan, C. L., Dheer, J. M. S. 1980. Origin and development of neutrophils in an air breathing fish, Channa punctatus Bloch. (Department of Zoology, University of Rajasthan, India.) — Acta zool. (Stockh.) 61(4): 221–224. An account of the study of the development of neutrophils based on detailed examinations of kidney and spleen imprints has been given in this paper. Each developmental stage has been investigated with respect to its morphology, morphometry and cytochemistry using certain special techniques developed in this laboratory for fishes such as differential haemoglobin staining, autoradiography etc. Five main stages (large lymphoid haemoblasts, promyelocytes, mesomyelocytes, metamyelocytes, mature neutrophils) have been identified in development and are described in detail.     

In vitro free radical scavenging activity of hepatic metallothionein induced in an Indian freshwater fish, Channa punctata Bloch

Mammalian metallothioneins (MT) have been reported to scavenge free radicals. There is no experimental evidence to show that fish MT has a similar property. In the present study cadmium-induced MT (Cd-MT) from the liver of an Indian freshwater fish Channa punctata Bloch was investigated for its free radical scavenging activity using three different in vitro assays. Exposure to cadmium chloride (0.2 mg/kg body weight; three doses on alternate days) resulted in a marked induction of Cd-MT in liver. Only a single isoform of Cd-MT was found to be induced. Molecular weight of Cd-MT was found to be 14 kDa as deduced by SDS-PAGE analysis. The purified Cd-MT effectively scavenged the following free radicals: superoxide radical (O2*-), 2,2'-azinobis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS*+) and 1,1-diphenyl-picrylhydrazyl radical (DPPH*). The radical scavenging effect was found to be concentration-dependent. Also, the purified MT exhibited an inhibitory effect on ferric nitrilotriacetate (Fe-NTA) induced oxidative DNA damage in vitro. The cysteine residues of MT are proposed to be the main candidate for its radical scavenging activity. Findings of the present study strongly suggest a free radical scavenging role for fish MT. Present study adds to the little existing knowledge about fish MT and its possible biological functions.     

Ontogenetic changes and developmental adjustments in lactate dehydrogenase isozymes of an obligate air-breathing fish Channa punctatus during deprivation of air access

In air-breathing snakehead Channa punctatus, Ldh-B is expressed at all ontogenetic and developmental stages, while Ldh-A is expressed temporally in pre-hatchlings 12-13 days ahead of bimodal respiration marked by air-breathing. Remarkable differences are observed in the LDH isozyme expression among various ontogenetic and developmental stages upon denying air access. When denied air access, water-breathing larvae show two distinct characteristics: (i) they survive longer than transitory air-breathers due to independence from air-breathing and (ii) there is more transient induction of Ldh-B than Ldh-A. Transition to bimodal breathing, which occurred post-hatching in 15-day old larvae, is coincidental with inducibility of Ldh-A and concomitant down-regulation of Ldh-B. Heart tissue from air-breathing adults denied air access shows a preferential expression of LDH-A subunit and slight down-regulation of LDH-B. Heterotetramers of A and B subunits participate in adjusting LDH levels among those stages which either precede air-breathing switchover, or are subsequent to this transition. The contribution of heterotetramers depends on the stage-specific levels of LDH homotetramers A(4) or B(4). Scaling of muscle mass during growth, tolerance to extended deprivation of air access and induction of Ldh-A are correlated. Response to restoring air contact indicated that advanced air-breathing stages of C. punctatus possess an inherent capacity to sense surface air. In kinetic properties, LDH isozymes of C. punctatus are teleost-like but species specificity is displayed in oxidative potential by cardiac muscle and in L-lactate reduction by skeletal muscle.