Print This Page

January 12, 2014

United States

Hawaii—Broodstock and Inbreeding

 

Shrimp breeders invest a lot of money in the development of genetically improved broodstock, but how can they profit from their investment if their customers reproduce the broodstock they buy without permission?  Or even worse, what can they do if their customers compete with them by selling postlarvae at prices that don’t reflect the cost of genetic research and development?

 

Shrimp breeders can protect their genetic investments with inbreeding programs, which have a surprisingly high effect on the growth of later generations, especially when the shrimp are farmed in inferior environments.

 

There is not a lot secondary breeders can do to escape the genetic traps set by vigilant primary breeders.  The best strategy for hatcheries is to purchase the latest generation of improved broodstock every year.

 

In a study conducted by Moana Technologies at its breeding center in Kona Hawaii, USA, black tiger shrimp were inbred for three generations to quantify the differences in performance between inbred and non-inbred Penaeus monodon.

 

After one generation of brother-sister mating (25% inbreeding), non-inbred shrimp grew 24% faster than inbred shrimp, but survival was only 5% lower in the inbred shrimp.  During a disease challenge conducted at a biosecure testing facility, non-inbred and inbred shrimp in an untreated control tank also showed a 24% difference in growth—22.3 versus 17.9 grams—respectively.

 

However, in tanks into which disease agents were introduced, there was a 50% difference in growth between non-inbred and inbred shrimp.  This clearly showed the danger of growing inbred shrimp in the presents of a stressor.

 

After two generations, the 25%-inbred shrimp were mated by artificial insemination for another generation to produce 37.5%-inbred shrimp.  This level of inbreeding had a very large effect on performance, as the inbred shrimp grew 56% slower, and survival was 49% lower than for non-inbred individuals.

 

After three generations, the 37.5%-inbred females were crossed again with their brothers to obtain 50%-inbred shrimp.  There was a significant difference in growout performance, although it was not as large as seen in the 37.5%-inbred shrimp.

 

This decrease in performance should encourage potential copiers to return to the breeding company for all their broodstock supplies.  In addition, farmers should demand that they only receive original seed and not “copied” seed.

 

Sources: 1. The Global Aquaculture Advocate (The Global Magazine for Farmed Seafood.  The current issue of the Advocate is free, online at GAA’s website).  Editor, Darryl Jory (dejry2525@aol.com).  Production/Inbreeding Cuts Growth, Reproduction in Shrimp.  Brad Argue (email brad@moanakona.us, Moana Technologies, 73-4460 Queen Kaahumanu, Highway #121, Kailua Kona, Hawaii 96740, USA), Geovanni Tolentino and J.A. Brock.  Volume 17, Issue 1, Page 30, January/February 2014.  2.  The Global Aquaculture Advocate.  Editor, Darryl Jory (dejry2525@aol.com).  Shrimp Copyright.  Roger W. Doyle (Genetic Computation, Ltd., 4630-1 Lochside Drive, Victoria, British Columbia, Canada V8Y2T1, email rdoyle@genecomp.com), Dustin Moss and Shaun Moss (The Oceanic Institute, Waimanalo, Hawaii, USA).  Volume 9, Issue 2, Page 76, April/May 2006.

Print This Page