Seasonal changes in the blood parameters of two major carps, Labeo rohita (Ham.) and Cirrhina mrigala (Ham.).

Seasonal changes in blood properties of two Indian major carps, L. rohita and C. mrigala, were investigated. Haematocrit values, haemoglobin concentrations and erythrocyte numbers showed seasonal fluctuations, being high from September to November and again in April-May, and low from January to March. Males had generally higher blood values than the females.     

Sublethal temperature stress in juvenile Labeo rohita (Ham-Buch.) and Rita rita (Ham.): some physiological changes

Juveniles of fish L. rohita and R. rita subjected to a rapid (5 min) sublethal temperature increase from 28 to 35 degrees C showed significant increase in cortisol and decrease in interrenal ascorbic acid. Hypercholesterolemia, hyperglycemia and hyperlactemia were also evident accompanied by increased blood haemoglobin and haematocrit and stable protein levels. Compensatory responses were initiated within 72 hr in both the fishes. R. rita recovered more quickly indicating it to be more resistant to the heat stress than L. rohita. Hence fishes subjected to sublethal temperature stress should be given a metabolic recovery period of 72 hr prior to further stress being applied.     

Melanophore characteristics in a fresh-water teleost, Puntius conchonius (Ham.)

The present study is an attempt to determine the factors responsible for the melanophore pattern of the freshwater teleost, Puntius conchonius (Ham.) under normal background conditions (i.e., the existence of a large round black spot on the middle of the side above the posterior part of the anal fin and the dull shade of the rest of the body which is brownish on the dorsal part, referred here in the present study as the general body surface and silvery along the lateral and ventral part of the body). On the basis of nature of their branching pattern various morphological types of melanophores are classified in a scale from the dark spot area as well as the general body surface. There are as many as 7 types of melanophores termed as A, B, C, AB/AC (all system I deep melanophores) and a, b and c (all system I superficial melanophores). The integument of the fish, however, possesses 3 kinds of chromatophores namely--melanophores, xanthophores and iridophores. The identity of the dark spot as clearly maintained entity independant from the general body surface may be attributed to greater number of system I melanophores, greater melanin content in the system I and system II melanophores, smaller interspaces between system I and system II deep melanophores, greater anastomosing in the superficial melanophores, larger size of system I deep as well as superficial melanophores. The reverse order of the above mentioned factors is responsible for the dull-brownish shade of the general body surface of the fish. The dark spot toward the tail end in the fish, possibly may serve to intimidate or misdirect attack and thus facilitate escape.     

Effect of follicle stimulating hormone on female Catla catla (Ham.)

The exogenously administered FSH in Catla catla clearly reveals that a dose of 0.2 mg and 0.4 mg of FSH does not have any marked effect on the ovary, but the vitellogenesis begins with a further dose of 0.2 mg of the same. A rapid accumulation of yolk is recorded in the primary oocytes with a total dose of 0.8 mg of FSH, however, this much hormone is not enough for the spawning. The latter has been recorded with 1.0 mg of FSH which swifts with a dose of 1.2 mg of FSH. The number of mature follicle declines with 1.4 mg of FSH whereas no empty follicle is seen with the same treatment. With each addition of 0.2 mg of FSH upto 2.0 mg the number of oogonia and primary oocytes increases while maturing and mature follicles show a downward tendency.     

Effect of formulated diet on digestive enzymes of Labeo rohita (Ham.)

Six sets of feeding experiments were carried out using formulated diets containing prawn head waste (PW), chicken intestine waste (CW), banana flower (BF), cauliflower waste (CAU) Dolicos lab lab (DLL) and groundnut leaf (GNL) in four levels of inclusion (15, 30, 45 and 60%) to assess the pattern of distribution and activities of digestive enzymes like cellulase, amylase, maltase, invertase, protease and lipase in the digestive tracts of Labeo rohita fingerlings. A control group of fish was fed with diets containing antibiotics to destroy the digestive tract microflora which may induce digestive functions. In general, the activity of digestive enzymes depended on the amount and type of the ingredients present in the diets ingested by the fish. Test animals showed both endogenous and bacterial cellulase activities which suggests the necessity for including cellulose (plant protein source) as dietary ingredient. Occurrence of higher amount of cellulase in the foregut and amylase in the fore and midgut influenced by DNL and GNL diets revealed the possibility of including less than 40% of the respective ingredients in the diet of rohu. Maltase and invertase were highly influenced by GNL, DLL and BF diets than PW and CW diets. More than 40% inclusion of PW and CW was found to increase protease and lipase secretion in the midgut and hindgut regions. The higher secretion of lipase in the midgut suggested the physiological versatility for lipid digestion in rohu fingerlings.     

Ovarian steroid sulphate functions as priming pheromone in maleBarilius bendelisis (Ham.)

The study reveals that pre-ovulatory females of the fishBarilius bendelisis (Ham.) release sex steroids and their conjugates into the water and that a steroid sulphate of these compounds functions as a potent sex pheromone which stimulates milt production in conspecific males prior to spawning. Since males exposed to the purified sub-fraction III of the steroid sulphate fraction have increased milt volume and more spermatozoa with greater motility, the function of this priming pheromone appears to be to enhance male spawning success. High turbulence and faster water currents render the hillstream ecosystem extremely challenging for chemical communication. Therefore, ovulatory female fish secrete highly water soluble steroid sulphates for rapid pheromonal action in males. Inhibited milt volume in olfactory tract lesioned (OTL) males exposed to the steroid sulphate fraction and 17α,20β-dihydroxy-4-pregnen-3-one supports the concept that the pheromonally induced priming effect in male fish is mediated through olfactory pathways.     

The hypothalamo-neurohypophysial system in Indian fresh-water goby, Glossogobius giuris (Ham.)

The hypothalamo-neurohypophysial neurosecretory system in Indian fresh-water goby, Glossogobius giuris (Ham.) has been described. The tractus preoptico-hypophyseus serves the function of a morphological and physiological connection between the hypothalamus and pituitary gland. In addition to main mass of the nucleus preopticus cells (cystine/cysteine bearing), a group of few cells in the hypothalamus has also been observed. These cells are situated posterior to the position of the nucleus preopricus and are CH Ph + ve and AF + ve. The neurosecretory material in the cells of nucleus preopticus is in the form of fine granules. The nucleus lateralis tuberis is absent in the fish under study. The disposition of neurosecretory material is heaviest along the fibres of the neurohypophysis in the region of pars intermedia with which it forms a profuse interdigitation. The fibres usually terminate over the blood vessels. The Herring bodies are noticeable at different levels in the neurohypophysis and pars-distalis. Besides the neurosecretory fibres, Herring bodies, non-stainableneurosecretory fibres and blood vessels, the pituicytes are also present in the neurohypophysis (SAKSENA 1974a, b). The intraaxonal flow of neurosecretory material, the vascularization of the nucleus preopticus and hypothalamo-hypophysial regulatory mechanism have been also discussed.     

Development and characterization of three new diploid cell lines from Labeo rohita (Ham.)

Development of cell lines from fish for identifying the pathogenesis of viral diseases and for vaccine production against viral and bacterial diseases is imperative where they are of commercial importance. Three new diploid fish cell lines (RF, RH, and RSB) were developed from fin, heart, and swim bladder of an Indian major carp, Labeo rohita, commonly called Rohu. All the cell lines were optimally maintained at 28°C in Leibovitz‐15 medium supplemented with 10% FBS. The propagation of RH and RSB cells was serum dependent, with a low plating efficiency (<16%), whereas RF cells showed 20% efficiency. The cytogenetic analysis revealed a diploid count of 50 chromosomes. The cells of RF and RSB were found to be epithelial, where as the cells of RH were mostly fibroblastic. The viability of the RF, RH, and RSB cell lines was 75, 70 and 72%, respectively after 6 months of storage in liquid nitrogen. The origin of the cell lines was confirmed by the amplification of 496 and 655 bp fragments of 16S rRNA and Cytochrome Oxidase Subunit I (COI) of mtDNA. The new cell lines would facilitate viral disease diagnosis and genomic studies. © 2010 American Institute of Chemical Engineers Biotechnol. Prog., 2010