Veterinary Archives, Vol. 69 No. 2, 1999.
Original scientific paper
Response of aerial respiratory organs of the air-breathing catfish Heteropneustes fossilis (Bloch) to extreme stress of desiccation.
Ram Sanehi Parashar
; Histochemistry and Histopathology Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, India
Tarun Kumar Banerjee
; Histochemistry and Histopathology Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, India
Abstract
Histopathological alterations caused by desiccation stress in the aerial (accessory) respiratory organs (ARO) of Heteropneustes fossilis which has a developed bimodal respiratory mechanism for exploitation of water (through its gills) as well as air (through its ARO) have been described. The ARO assist the fish in surviving extreme drought conditions. When out of water, even though the fish survive for about 16 h, their air sacs suffer extensive damage. In the initial stages the fish very frequently open their mouths to gulp in more air. The blood channels of secondary lamellae of the ARO, engorged with ridged blood channels, exhibit extensive protrusion into the lumen where they form a network of very thin-walled tube-like structures. Prolonged desiccation causes wear and tear to these greatly extended blood channels, leading to haemorrhaging into the lumen. Simultaneously, from the blind ends of the ARO, many of the ridges approach very close to each other and finally meet, leaving no free respiratory surface in the lumen to breathe aerially, ultimately resulting in failure of aerial respiration and the demise of the fish.
Keywords
accessory respiratory organs; desiccation; Heteropneustes fossilis; histopatho-logy; air-breathing catfish; India
Hrčak ID:
105176
URI
Publication date:
18.4.1999.
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