15 May 2019
Epigenetics in Shrimp – The Future of Shrimp Breeding?
Written by Zach Stein

Shrimp breeding programs are on a constant quest to produce broodstock that will grow faster, be more resistant to stressors in the environment such as dissolved oxygen swings, and be tougher in the face of disease.

While shrimp breeding programs are generally getting more advanced with greater data tracking, more family lines, and a combination of practices from SPF, to SPR, to APE, there is another very exciting practice on the horizon – epigenetics.

In this post we explore epigenetics and its potential impact on shrimp breeding and the farmed shrimp industry as a whole.

What is Epigenetics?

Epigenetics is the study of the impact of traumatic events on the genes of a being’s offspring. At the lab level, it has been studied in controlled settings using mice and zebrafish, and in the real world, it has been studied by tracing family lineages back through regional traumatic events and seeing what impact it has had on a population generations later.

Famous examples include studies of the survivors of famines with the results being that the generations that come later from their lines are generally tougher, resulting in longer lifetimes.

While the causes of these epigenetics transformations in response to traumatic events is still being understood by scientists, the data is indicating that the results of these transformations are real and can have a major impact, particularly in animal husbandry industries, like shrimp.

How Are Shrimp Bred Today?

While advancing, shrimp breeding is done today using traditional animal husbandry methods, which is essential Darwinian “survival of the fittest.” A generation of shrimp is bred, then subjected to tests to allow the strongest to emerge. These strongest are then cared for until they reach broodstock size and then are bred again and the process is repeated.

With careful record keeping, generations of shrimp grow and are selected for specific qualities such as growth rates, disease resistance, and survival when shocked (temperature swings and salinity changes). Once the broodstock reaches certain thresholds then they can be sold to hatcheries who will continue to raise them and sell PL’s to farmers.

With such methods, genetics companies can get far ahead of their competition as it can take 180 days to raise a new batch of potential broodstock from PL to ready to mate.

What Could the Impact of Epigenetics Be on Shrimp Breeding Programs?

With the advent of epigenetics, shrimp genetics companies may be able to add another tool in their toolbelt of practices to raise stronger animals. Early studies have shown that subjecting a generation of animals to a specific shock, like a heat shock and keeping the survivors alive to breed results in later generations showing significantly more tolerance to such events.

As this research progresses, the implications could be huge on the world of shrimp as genetics programs could take a quantum leap forward in staying one step ahead of diseases and other expected environmental shocks.

In this way, genetics companies can shortcut the “random” part of “random selection.” By subjecting animals to specific traumas (yes it sounds inhumane, but so are poor survival rates), they can purposefully produce offspring that are genetically hardier in the face of such shocks. For example, with ocean pH’s rising due to global acidification from climate change, genetics companies would not only just select the shrimp that randomly that survived in lower pH water, but could purposefully subject the animals for longer exposure times, thus further shocking them, and potentially leading to altered genetics for the better in the future.

Conclusion

We focus a lot of the future of shrimp farming in this blog, and epigenetics has a very high potential in revolutionizing shrimp breeding programs, leading to a more stable industry, higher survival rates, and more money in the pockets of farmers.