The present work is an endeavour to study some aspects of hormonal regulation on nutritional energetics in a fresh water snake headed murrel fish, Channa punctatus (Bloch). Effect of L-thyroxine, triiodo-throxine, 17a or p -Methyl testosterone and growth hormones were studied on food consumption rate, feeding efficiency, conversion ratio, growth and as a whole on bioenergetics in a freshwater fish，Channa punctatus (Bloch). These hormones served as an apetite stimulant and consequently both feeding and growth rate increased. The best performance was observed after the injection of 17 a or p – Methyl testosterone. The reason for such changes has been discussed in this paper.

Studies on total corpuscular and plasma volume in relation to body weight have been made in an air breathing siluroid fish，Clarias batrachus (Linn) by Dye dilution technique using Evan blue (T-1824) for plasma volume and haematocrit method for corpuscular volume. Plasma and corpuscular volume per gram body weight decrease from lower to higher weight groups but become constant at 70 gram animals. The total plasma and corpuscular volume increase from lower to higher weight groups. They show the following relationship:

Body weight Vs. Plasma volume logY =log 0.0130+0.9227logW

Body weight Vs. Corpuscular voi logY = logO. 0309+0.6000 logW

Plasmavol. Vs. Corpuscularvol. logY=log0.5192+0.6479logW

The coefficient of correlation between body weight Vs. Plasma volume, body weight Vs. corpuscular volume and between plasma volume Vs. corpuscular volume have been computed in be 0.9989, 0.9980 and 0.994 respectively. This shows high degree of correlation between all the foregoing parameters and sed

  A biometric study of growth of various body parameters in relation to standard body length, length- weight relationship, relative condition factor and fecundity of the mud eel (Mastacembelus armatus) has been made. The fastest growing body parameters is the region between the snout and ventral fin. This is followed in decreasing order by snout to dorsal fin, pectoral fin to anus, breadth at the dorsal fin, snout to pectoral fin and head length. The length-weight relationship follows the cube law during summer months. The male and female fish become sexually mature when they attain a length of 15.5cm (just above 15gand nearly 18cm (22g) respectively. The fecundity of this species is very low (210-1828). The advantges and disadvantages of the form aquired by M.armatus in response to selection pressure are discussed. The peculiar shape, growth pattern of body paramters and low fecundity render this fish totally unsuitable for commercial exploitation.

  In the present work an attempt has been made to study the changes in certain haematological indices following Cythion (an organophosphate pesticide) treatment in a teleostean fresh water air breathing murrel fish，Channa gachua (Ham) which are also cultured in paddy fields. The treatment of Cythion caused anaemia i.e. significant decrease in RBC counts, Hb content and PCV values. However, a clear trend of increase in WBC counts，MCV and MCH was observed. MCHC values did not differ much orto a significant level. The details have been discussed in this paper.

  In the present work an attempts has been made to evaluate the toxicity and behavioural responses of two most commonly used pesticides namely Merit Alpha (an organochlorine) and Mardo (Organophosphate) in a fresh water siluroid fish，Rita rita (Ham.). The 24 hrs LC50 values for Merit Alpha and Mardo were 0.0059 mg/I and 0.445 mg/I respectively. A shift from normal behaviour was observed in fish upon exposure to different lethal concentrations of both the pesticides. The details have been discussed in this paper.

Fish culture is an important enterprise especially in the Kosi region of Bihar. In the present investigation, a survey has been made in three districts of the Kosi region to find out the adoption of fish farming recommendations to the farmers. It has been found that the literacy rate among fish farmers in the region is 41.6% and 73.3% of farmers are trained in fish farming. The average pond size is 0.37 ha and 56.6% ponds are perineal. About 70% ponds are older than 15 years, 46.6% fish farmers prepare their pond before stocking,40% farmers remove unwanted plants before stocking the pond 46.6% farmers use organic manure in the pond and 40% use lime and 46.6% use inorganic fertilizers while stocking the pond,23.3% farmers stocks the pond with spawn and 30% farmers uses three fish species in the pond. Before stocking the seeds about 70% farmers treat the seed fordiseases.20% farmers feed the fishes with formulated feed as supplementary feeding. 93% of farmers feed their fishes for more than six months, 96% farmers contact to Department of Fisheries in case of adverse conditions observed during the culture period.

Zinc is an essential trace element for humans and plays a critical role both as a structural component of proteins and as a cofactor in about 300 enzymes. Excessive zinc intakes can produce acute and chronic effects of toxicity. Differential leukocyte counts represent important characteristics of the health status of fish and in many cases they are also helpful in evaluating their immune system. In the present investigation, Heteropneustes fossilis were exposed to the essential heavy metal, zinc. Acclimatized fishes were divided into four different groups: Group A (Control),Group B (1:00 ppm ofZn), Group C (3:00 ppm ofZn) and Group D (6:00 ppm ofZn) during different exposure periods (7 Days, 14 Days, 21 Days and 28 Days). The results indicated pronounced effects on the blood picture. The small and large lymphocytes reduced significantly, the most conspicuous changes being in group C at 28 daysexposure. The control value of small lymphocyte was 42%，the maximum reduction of small lymphocyte was 33% in group D at 28 days post treatment while the large lymphocytes were reduced by 27% during maximum exposure period (28 days) at minimum concentration of zinc (1:00 ppm). Maximum increase in the percentage of neutrophils was 28% during 28 days exposure period at 3.00 ppm ofZn (Group C). Maximum increase in the number of monocytes was 6% during 7 days in group C and 21 days in group D. The highest increase in eosinophils was 6.0% (28 days: 1.00 ppm of Zn). Basophils showed little fluctuation in their values {0-3%).The above examinations indicated that the small and large lymphocytes decreased while the neutrophils, monocytes and basophils increased in their concentration. It can be concluded thatthe findings related to D.L.C. changes can effectively be used as important indicators of zinc-related stress in fish.

Present study was conducted to study the effect of varying level of dietary lipid on the growth, feed conversionratio (FCR) and body composition of the juveniles of Labeo rohita. Group of 25 juveniles in triplicate (average weight0.022 gm ± 0.002 gm) were fed on three iso-nitrogenous experimental diets containing (40% protein) and varying levels of lipid i.e., 6%, 9% and 12% fora period of 60 days. Results revealed that the best increment in growth was obtained with 9% supplementary lipid (%WG 26.08 ± 0.681) followed by the diet containing 12% lipid (%WG 23.41 ±1.646) and least with 6% lip 丨d (%WG 22.71 ± 1.540). FCR and feed conversion efficiency(FCE) shows inverse relation as highest value ofFCE(9.35) and least

value of FCR (10.70) was obtained in juveniles fed on 9% lipid diet with significant differences (p ^ 0.001). Further biochemical analysis revealed that highest value of muscle lipid has been found in juveniles fed on9% lipid diet i.e., 1.11 gm and least with diet containing 6% lipid i.e., 0.78gm. Thus, based on the present results, itcould be concluded that an artificial feed with 9% supplemented fish oil is sufficient without any adverse effects ongrowth performance and muscle quality.

  The medicinal plants synthesise numerous phytochemicals which have potential biological activity, which affect and alter the membrane of human Erythrocytes. In the present study, the comparative an invitro haemolytic study of different extracts of Agave americana has been evaluated. The Methanolic, Ethyl acetate, Chloroform and Benzene was assayed on human erythrocytes(RBCs) with different concentration. The various extracts of Agave americana on human erythrocytes(RBCs) for haemolytic activity with expose of increasing concentration The exposed concentration was 0-500fjg. Ethyl acetate extracts of Agave americana showed haemolytic activity and it was found that IC50 at 300 ^ig and IC90 at 350fjg.

Pesticides used in agricultural fields create a series of toxicological and environmental problems. Methyl parathion (MP)，an organophosphorus (OP) insecticide is a widelyused pesticide and is highly toxic to non-target organisms. Fish has been used as indicator speciesfor monitoring of pollution in the aquatic environment Mystus seenghala，an Indian major carp is an edible fish and is highly sensitive to slight stress. Recently, fish biomarkers are widely used to determine the internal and external health status caused by chemicals.

WhenM. seenghala were exposed to acute (0.09 ppm) and sub lethal (0.009 ppm) concentrations of MP to determine the alterations in antioxidant and metabolic enzyme activities in blood plasma. Intoxication with MP resulted in induction of oxidative stress which implies that fish utilizes enzymatic mechanisms to tolerate the effects caused by generated ROS due to MPaccumulation. Significant alterations in GOT and GPT activity in plasma during acute as well as sub lethal exposure might have resulted from the organ damage. Further, MP should be used with caution in order to protect natural waters and aquatic organisms