Latest Research on Heteropneustes Fossilis: Dec – 2019

Photoperiod and Temperature Control in the Regulation of Reproduction in the Female Catfish Heteropneustes fossilis

The annual reproductive cycle of the catfish Heteropneustes fossilis is split into the preparatory period (February–April), prespawning period (May–June), spawning period (July–August), and postspawning period (September–January). Ovarian recrudescence, which normally occurs during the prespawning period, are often advanced by photothermal manipulations. During the postspawning and preparatory periods, the tempo of ovarian recrudescence is far faster at 30 C than at other temperatures (ambient, 25 or 34 C) no matter photoperiod (14L + 10D, 12L + 12D, or 9L + 15D).Warm temperature (30 C) postpones the postspawning ovarian regression only up to the primary week of October no matter photoperiod. The ovarian cycle is regulated by a circannual rhythm which may be activated 5 mo earlier, but its activity can’t be prolonged beyond October by photoperiodic and temperature manipulations.Interruption of the night of a brief day (6L + 18D) treatment by 1 h of sunshine between 0000 and 0100 induces ovarian recrudescence that’s significantly greater than that obtained within the control group exposed to 7L + 17D. [1]

Active ureogenesis in a freshwater air‐breathing teleost, Heteropneustes fossilis

Activities of all the enzymes of ornithine‐urea (o‐u) cycle and uricolytic pathway were assayed in several tissues of a freshwater air‐breathing teleost, Heteropneustes fossilis. High activity of all o‐u cycle enzymes as observed within the liver and kidney, were like those of actively ureogenic fishes and amphibians. All the three enzymes of uricolytic pathway were found only in liver tissue. These observations strengthen an earlier suggestion made that active ureogenesis did exist in some freshwater teleosts like H. fossilis. Presence of a lively o‐u cycle in H. fossilis indicates that this fish is either relatively primitive to the purely aquatic freshwater teleosts retaining the ancestral character of a functional o‐u cycle or the genes for the synthesis of o‐u cycle enzymes may need been derepressed as a secondary modification for its adaptation to temporary dehydration or hyper‐ammonia environment. [2]

Steroid-induced synthesis of vitellogenin in the catfish, Heteropneustes fossilis (Bloch)

The synthesis of vitellogenin, the egg-yolk precursor, was induced by estrogenic steroids (estrone, estradiol, and estriol) but not by testosterone, progesterone, or cortisol; estrogen treatment alone didn’t cause formation of yolky oocytes within the hypophysectomized catfish. Amplification of vitellogenin synthesis was observed following three spaced injections of estradiol as primary, secondary, and tertiary responses in intact males or hypophysectomized females. The pattern of 32P incorporation indicated that the label was first incorporated into the phosphoprotein fraction of the liver of estrogenized males or females and thereafter labeled vitellogenin appeared in blood. Thus, within the catfish, liver is that the site of estrogen-induced synthesis of vitellogenin. [3]

Multiple Hæmoglobins in Fish

THOUGH there are reports by different workers1,2,3 about the concentration of hæmoglobin in several species of fish, no information seems to be available within the literature about hæmoglobin patterns of fish. This communication deals with the findings on the blood samples of 10 different species of freshwater fish: Catla catla, Labeo rohito, Cirrhina mrigala, Labeo calbasu, and Labeo bata (family Cyprinidæ), Ophicephalus punctatus Bloch and Ophicephalus striatus Bloch (family Ophicephalidæ), Heteropneustes fossilis (Bloch) (family Heteropneustidæ), Clarias batrachus (Linn) (family Claridæ) and Tilapia mosambica (family Cichlidæ). [4]

Effect of Dimethoate on Prolactin Cells of Freshwater Catfish Heteropneustes fossilis after Short-term and Long-term Exposure

The effects of dimethoate on pituitary prolactin cells of Heteropneustes fossilis was investigated during this study. The fish Heteropneustes fossilis were subjected to sub-lethal concentration of dimethoate – 2.24 mg/l i.e. 75% of 96 h LC50 for short-term (24, 48, 72 and 96 h), and 1.00 mg/l i.e. 25% of 96 h LC50 for long-term (6, 12, 24 and 36 d) exposure. Pituitary was faraway from anaesthetised fish and glued for histological examinations. H. fossilis exposed for short-term (96 h) at sub-lethal dimethoate concentration, exhibited marked changes in structure and marking properties of prolactin cells. PRL cells didn’t show much histological alterations after 24 h, however, after 96 h exposure exhibited severe vacuolization and nuclear pycnosis, indentation and deformity of nuclear boundaries. [5]

Reference

[1] Sundararaj, B.I. and Vasal, S., 1976. Photoperiod and temperature control in the regulation of reproduction in the female catfish Heteropneustes fossilis. Journal of the Fisheries Board of Canada, 33(4), (Web Link)

[2] Saha, N. and Ratha, B.K., 1987. Active ureogenesis in a freshwater air‐breathing teleost, Heteropneustes fossilis. Journal of Experimental Zoology, 241(1), (Web Link)

[3] Sundararaj, B.I. and Nath, P., 1981. Steroid-induced synthesis of vitellogenin in the catfish, Heteropneustes fossilis (Bloch). General and comparative endocrinology, 43(2), (Web Link)

[4] Multiple Hæmoglobins in Fish
N. CHANDRASEKHAR
Nature volume 184, (Web Link)

[5] Pandey, R. (2017) “Effect of Dimethoate on Prolactin Cells of Freshwater Catfish Heteropneustes fossilis after Short-term and Long-term Exposure”, Annual Research & Review in Biology, 15(5), (Web Link)

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