歐洲的鰻魚人工繁殖的新方法

專利 ZF植入® 包含斑馬魚胚胎激素生產細胞，植入鰻魚，可以繞過腦下垂體生產所需的LH和FSH。

ZF IMPLANT

(http://www.newcatch.nl/)

Development of ZF-implant® is based on our patented novel cell-therapy platform, enabling slow release of glycosylated proteins by using embryonic zebrafish cells.

In large scale fish production, it is essential that reproduction and season independence are synchronized. In most animals the reproduction is regulated by LH and FSH, two pituitary hormones. The pituitary in the brain is controlled by two mechanisms, GnRH and dopaminergic innervations (signals that come from the environment, like temperature, day length, and food). These mechanisms are hard to manage, especially in species in which the inhibition is very strong.

This difficulty can be overcome with the direct and repeated injections of LH and FSH, but these are very expensive substances and above that the injections cause a lot of stress and rapidly changing hormone levels in the fish. Eventually this causes failure for most fish species to reproduce in captivity.

NewCatch BV has a promising solution to these problems. The patented ZF-implant® comprises hormone-producing embryonic zebrafish cells, which, when implanted in other fish like eel or sole, can bypass the pituitary and lead to the desired production of LH and FSH.

The key benefits for this product are: - season independance - low interference - less stressful for fish - continuous hormone release

Farming of wildcatch

At this moment only few fish species can be bred on a fully controlled production scale manner (salmon, trout and tilapia). The farming of other species is dependent on stocking of the farms with wild caught juveniles, which is unsustainable due to declining wild juvenile stocks. It is also inefficient, since most of the time the juveniles have large differences in growth rate.

Reproduction problems in captivity

Species bred in a controlled manner are usually dependent on the use of small peptides (sex-hormones), which are used to induce synchronized spawning of the broodstock. These small peptides, together with other external signals have an effect on glands that produce gonadotropins, which have in turn a direct effect on the development of the gonads. For some species these gonadotropins are also used as a spawning aid, like in Alantic salmon.
Moreover, the disadvantage of the use of small peptides like GnRH is that their effect is season-dependent and that the small peptides could diffuse out of the fish's body into the environment. The disadvantages of injection of gonadotropins are that they are very expensive, they require multiple injections, and they are sometimes extracted from the brains of other fish which poses the risk of spreading diseases.
Our method offers the possibility to culture species year-round, whereas currently most cultures are limited to the spawning season. In the future, ZF-implant® can be implanted in the most profitable species, where they induce maturation and start producing natural offspring. This offspring, called fingerlings, can be a solution in farms that are now dependent on the wild catch of fingerlings.