Surrogate Broodstocking
Japanese researchers engineered salmon to produce trout, in a quest to preserve endangered fish. Idaho scientists will begin the next step, trying to produce sockeye salmon, which is endangered in Idaho, this time using more plentiful trout as surrogate parents.
The Tokyo University scientists dubbed their method "surrogate broodstocking." They injected newly hatched but sterile Asian masu salmon with sperm-growing cells from rainbow trout.
The Japanese researchers' ultimate goal is to boost the rapidly dwindling population of bluefin tuna, a species prized in a country famed for its tuna appetite.
Once they were grown, 10 of 29 male salmon that got the injections produced trout sperm, called milt. Injecting the male cells into female salmon sometimes worked, too, prompting five female salmon to ovulate trout eggs.
The stem cells were still primitive enough to switch gears from sperm-producers to egg-producers when they wound up inside female organs. The salmon-grown trout sperm was used to fertilize both wild trout eggs and the salmon-grown trout eggs. DNA testing confirmed that all of the dozens of resulting baby fish were pure trout.
September 14, 2007 7:03 AM | Category: Fish