Survival Goldfishes can turn lactic acid into alcohol if they lack oxygen

Doctors discover the secret of why goldfish survive in winter without oxygen
Goldfish have the ability to survive in the dead of winter in ice-covered lakes. Scientists are now exploring the secrets behind this ability. Goldfish, therefore, convert the lactic acid in their body into alcohol to stay alive in the winter.

Researchers at the University of Liverpool and the University of Oslo found that goldfish can convert the lactic acid in their bodies to alcohol to survive in frozen lakes in winter. The physicians published the results of their study in the scientific journal "Scientific Reports".

Goldfish can survive in ice-covered lakes without oxygen. Physicians now discovered the secret behind this fascinating ability to survive. (Image: lamyai / fotolia.com)

Goldfish have a special ability to survive
Since the 1980s, experts have known about the special survival skills of goldfish and their wild, natural relatives, known as crucian carp. Humans and most vertebrates die within a few minutes if they do not receive oxygen. Goldfish, on the other hand, can survive for months in icy conditions in ponds and lakes in northern Europe, without their organism being supplied with oxygen, the authors explain.

In the absence of oxygen, the consumption of carbohydrates produces lactic acid in goldfish
Researchers now discovered the mechanism behind this interesting survivability. In most animals, there is only a single set of proteins that transport carbohydrates towards the mitochondria, which are the energy generators of cells. In the absence of oxygen, the consumption of carbohydrates causes lactic acid, which the goldfish can not degrade, the scientists explain. Normally, the lactic acid would kill the goldfish within a few minutes.

Proteins convert lactic acid into alcohol
Goldfish have developed a second set of proteins that can convert lactic acid to alcohol in the absence of oxygen. The produced alcohol is then released through the gills. This ability is activated only by oxygen deficiency, say the experts of the University of Liverpool. If goldfish can no longer get oxygen through an ice cover, the fish consumes all the oxygen and switches to alcohol.

Double set of genes provides useful functions
The longer the fish has to do without oxygen, the higher the alcohol content in the fish. The blood alcohol increases over 50 mg per 100 milliliters. The researchers said that the results show very important factors to better understand evolutionary adaptation. A double set of genes allow them to retain their original form, but still have a kind of backup set that can also provide useful functions.

Crucian ability reduces competition in the fight for survival with other fish
The ethanol production allows the crucians to survive in hostile environments. This ability avoids competition with other species of fish that normally live in oxygenated waters, explains author Dr. Cathrine Elisabeth Fagernes from the University of Oslo. (As)