الفهرس 
Experimental animalOnly 14 pages are availabe for public view
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Abstract
- Clarias lazcra is one of the most common and widely distributcd fresh water fish i n the world. - Clarias lazera wcri- trcansferred t o 100 % , 50 % and 25 9/0 sGa water in ordor to dctcct the h i s t o l o g i c a l changes which may happen in some organs, such as, skin, hcad kidney, mesonephrou- s, uret cr, urinary bladder, Stannius corpuscles, some
p a r t s of alimentary can21 and l i v e r . - Skin of Clarias l~~zecroan s i s t s o f two la,ycra,an o u t e r epi - dernfisan.3 c?y~ mner dermis, Tnc epidermis is composed of stratifiad epi thel ium with t h e mucous c~llsbe ing sczttcred between its pol-ygonal c e l l s . Aftcr living in 25 % sea water, a large incrc-ase in nwnbcr of the mucous cells was obszrved 2s 2, defensive mechmism to p r o t e c t t h e tissue from watcr l o s s . - The head kidney of Clarias lazera l i e s in front of the scpturn transversum b;ing unzonn~ct~wdi t h the r e s t o f the kidney and situated sornc distzncc awzy from the emb~ded l i v e r lobes. %a& lob2 of thc head kidncy is t r i a n g u l a r in appearance, Histologica~1t~h e~ ~he ctd kidiicy i s diff erentint~d.; tpto two regions : corticrzl and meiiullary. Aftcr tramfcrf+ the f i s h t o 25 % sca watcr no h i s t o l o g i c a l chaiiges wcre detected, - 135 - only more lymphoblast wcre obscrved i n trczted fish than in normal oncs. - A markcd shyinkage of thc glorwrulzr tuft was observed, after trmsfcm_ing the fish to 100 % sea water. The fishes took about 90 - 120 minut2s t o die. No other degenerative ctbaages wzrc scm lin thc kidney. - Aftccr transfedg tlic f i s h e s in 50 % sca water, it kook about 4 - 5 hours t o diz. A markcd shrinkage of the glomerular t u f t wes recorded. In the proximal and distal certpvoluted segment thc r a t i o of the r/R of the bxated are greater than the r a t i o of tllc control. - In the f i s h e s which were trmsft-rrcrlto 25 % sea water, characteristic changes wcrc induced in the kidney. In %he proximl convoluted segment, s l i g h t l y hyp crtrophy was observed aftcr 3 weeks of immrsion and the r a t i o of r/~f a greater than r/~of c o n t r o l showing thc widening o f lumen. Thc d i s t a l convolutcG segment did not show any hypertrophy, bu% thc r a t i o r/~l~ ~g-rs~ ~ttehrm normal. - The mcsonephric ducts soon aftm t h e i r origin inside %he renal mass i n th; ~nteriorr egion, come t o lie supaficially on the vcntrnl surface of thc kidney. Histologically, the uretcr of Clarias lazcra consists o f an outer muscular ’layer surrounding zn inncr c e l l u l a r one, After immersion in 25 96 sc2 vra-ter f o r ’j 2nd 6 w;-cksr th6 ur~tc-rd id n o t show any activ; sccrctLonsp as it is devoid of ,my goblet cells.