Nonsense. Here’s why.
It’s interesting that the high salt diet contained a full 10 times the amount of salt than the regular diet did. The Purina chow which they fed the Mongolian Gerbils contains the 0.75% salt. They added another 8% salt for a total of 8.75%.
That’s a bit like taking our normal consumption of 9g salt/day being bumped up to 99g/day. That’s not the way it works in real life.
Low salt diets for humans run around 3-4 g salt/day (the American Heart Association recommendation) and the highest salt consumption in the world (Northern Japan) runs around 12-14 g salt/day. In other words, a 4-fold increase between low and high.
In the gerbil study there was a 10-fold difference between low and high. A highly exaggerated case that has no relationship to real life. It is not particularly strange that they achieved this result since they placed an unusually high metabolic stress on the gerbils.