Changes in activity and transcript level of liver and gill metabolic enzymes during smoltification in wild and hatchery-reared masu salmon (Oncorhynchus masou)

Abstract

It is important for success of the masu salmon, Oncorhynchus masou, stock enhancement program in Hokkaido (northern Japan) to demonstrate physiological problems in hatchery-reared (hatchery) smolt for artificial release. The present study examined changes in liver and gill metabolic parameters in wild and hatchery masu salmon during smoltification and elucidated differences in hepatic and gill metabolism between wild and hatchery fish. As reference to freshwater-adapted wild and hatchery smolt in this study, metabolic parameters of coastal smolt were studied. Yearling wild and hatchery smolting fish were collected from the Ken-ichi River and the Donan Research Branch, which used Ken-ichi river water for fish culture, at the same time were no remarkable differences in hepatic and gill 3-hydroxyacyl-coenzyme A dehydrogenase related to lipolysis and creatine kinase activities, which operate in resolution of creatine phosphate, during smoltification between hatchery and wild fish.These results suggested hatchery masu salmon had some metabolic problems with carbohydrate metabolism, the citric acid cycle and the respiratory chain. Our study will give valuable information to improve physiological quality of hatchery smolt for artificial release.

Expression Analysis in Atlantic Salmon Liver Reveals miRNAs Associated with Smoltification and Seawater Adaptation

“…It has also been reported that β-oxidation capacity in liver increased significantly prior to seawater transfer which gives liver an important role in energy production during this period [16]. Citrate synthase activity in liver, gill and kidney was also enhanced during smoltification [18,20] and did not change after seawater transfer [21].…”

“…Subsequent oxidation of citrate provides the major source of cellular ATP production which is essential in the smoltification as it is a highly energy-demanding process [80]. The enrichment of the functional groups related to energy metabolism observed shows that miRNAs may fine tune the genes important in energy metabolism which is essential to success in this developmental transition [16,18,20].…”

Effects on the Liver Transcriptome in Baltic Salmon: Contributions of Contamination with Organohalogen Compounds and Origin of Salmon

“…While research on the effects of hatchery-rearing on survival and feeding has been conducted, there are fewer studies on the effects at the molecular level, for example, transcriptional changes. In the case of Atlantic salmon, studies have concentrated on the comparisons of wild vs. aquacultured salmon that have been under selection for faster growth, and the differences in transcriptome were notable as expected. − Studies on the effects of the feeding environment have been carried out with juvenile life stages such as embryos or smolts (e.g., refs ,,− ) but not in adult salmon. The feeding migration of the Baltic salmon differs at least partially according to their river of origin and whether they are wild or hatchery-reared.…”

Studies on Improvement of Seed Production Techniques in Salmonids and Osmerids

“…If the level of dorsal fin pigmentation is routinely examined in SFRIhatchery masu salmon, the hatchery workers can accurately determine the peak of smoltification without the slaughter of seed. On the other hand, Subsection 2-3 revealed that SFRI-hatchery smolt seed had some problems regarding the quality of the carbohydrate metabolism, citric acid cycle and respiratory chain (Mizuno et al 2012). Subsection 2-4 indicated that SFRI-hatchery smolt had defects in seed quality such as anemia, low energy levels and slow swimming performances.…”