DAO 37:209-220 (1999)  -  doi:10.3354/dao037209

Treatment with thiamine hydrochloride and astaxanthine for the prevention of yolk-sac mortality in Baltic salmon fry (M74 syndrome)

Perttu Koski1,*, Maarit Pakarinen2, Tarja Nakari3, Antti Soivio4, Kirsi Hartikainen2

1National Veterinary and Food Research Institute, Oulu Regional Laboratory, PO Box 517, 90101 Oulu, Finland
2National Veterinary and Food Research Institute, Department of Chemistry, PO Box 368, 00231 Helsinki, Finland
3Finnish Environmental Institute, Hakuninmaantie 4-6, 00430 Helsinki, Finland
4Finnish Game and Fisheries Research Institute, PO Box 6, 00721 Helsinki, Finland

ABSTRACT: Two practical methods are reported for treating feral Baltic salmon with thiamine hydrochloride against M74 syndrome (abnormally high yolk-sac fry mortality of the Baltic salmon). Both bathing of the yolk-sac fry in thiamine hydrochloride (1000 mg l-1, 1 h) and a single intraperitoneal injection given to the female brood fish (100 mg kg-1 fish) during the summer 3 mo before stripping were shown to elevate the whole body total thiamine concentration in the fry. Both treatments were also shown to be effective in preventing mortality due to M74 syndrome. The effect of bathing the yolk-sac fry was shown to be dose-dependent. The results support the view that there is a causal relationship between the thiamine status of the yolk-sac fry and M74 mortality. An intraperitoneal injection of astaxanthine suspension administered to the female brood fish (11 mg kg-1 fish) in the summer 3 mo before stripping elevated the astaxanthine concentration in the eggs but did not affect mortality due to M74 syndrome. An interaction between astaxanthine and thiamine may occur in the developing embryo or yolk-sac fry, however. No association could be demonstrated between the various thiamine hydrochloride treatment practices and hepatic cytochrome P450 dependent 7-ethoxyresorufin-O-deethylase (EROD) activity in the yolk-sac fry. An injection of thiamine hydrochloride into the peritoneal cavity of wild Baltic salmon females could be used to raise thiamine concentrations in their offspring in the rivers. The effect on smolt production in Finnish Baltic salmon rivers needs to be investigated further, however.


KEY WORDS: Salmo salar · Baltic salmon · Yolk-sac fry · M74 syndrome · Thiamine hydrochloride · Astaxanthine · EROD activity · Prevention


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