Prevention of Lagenidiales infections in Artemia salina larvae by high pH
of rearing water
H.
Yasunobu-2001
Fish
Pathology, 36(2): 79-82 (from
Current Contents)
Abstract :
The
effect of high pH (pH 9.25) of rearing water on the prevention of infection
of the brine shrimp Artemia salina larvae with four fungal species of
Lagenidiales was examined. The four fungi, all pathogenic to crustaceans,
were Halocrusticida parasitica isolated from greasyback shrimp Metapenaeus
ensis, Haliphthoros sp. and Haliphthoros milfordensis isolated from swimming
crab Portunus trituberculatus and Lagenidium callinectes isolated from mud
crab Scylla serrata. The in vitro growth of Halocrusticida parasitica was
reduced at pH 9.25 and no infection was observed in the brine shrimp exposed
to zoospores in the sea water at pH 9.25. The in vitro growth of
Haliphthoros sp. and Haliphthoros milfordensis was reduced at pH 9.25 and
infection rates at pH 9.25 were about half of the rate at pH 8. The growth
of L. callinectes was not arrested at pH 9.25 and the infection rate at pH
9.25 was 100%. These results indicate that the pH adjustment of rearing
water to 9.25 can be used to prevent infections with Halocrusticida
parasitica and the two species of Haliphthoros in swimming crab larvae, but
not for the infection with L. callinectes.
(Hyogo
Prefectural Fisheries Expt Stn, Minami Futami 22-2, Akashi, Hyogo 6740093,
Japan, e-mail: yasunobu@portnet.ne.jp)