Solubility of salt in heavy water vs. "regular" water
Well, consider a salt as $\ce{AB_s}$ in water you have :

$$\ce{AB}_s\rightleftharpoons \ce{A_{aq}^{q+} + B_{aq}^{q-}}$$

And $\Delta H_{s}=-\ce{U +\Delta H_{aq}}$ where $\ce{U}$ is the lattice energy.

When the salt needs to be solvate, $\ce{O-H}$-bonds of water molecules around this salt need to be rearranged. More, the "$\ce{DO}$-bonds" in $\ce{D_2O}$ are stronger than "$\ce{HO}$-bonds".$^1$ Then it will be harder to rearranged hence it will cost more energy to solvate the salt which will be then less soluble in heavy water than in water.

I found an article in the JACS and as you can see on the image below the maximum solubility of $\ce{KCl}$ in heavy water is a little less than in water (you can make a linear extrapolation) the difference is not quite importante but it looks it exists. 



Look at the second reference $^2$.



$^1$ : https://arxiv.org/ftp/arxiv/papers/0706/0706.1355.pdf, p-5


   Nuclear quantum effects are particularly important in the different
  properties of light (H2O) and heavy water (D2O) where the more restricted atomic vibrations in D2O
  reduce the negative effect of its van der Waals repulsive core so increasing its overall hydrogen bond 
  energy.


$^2$ : For the image, http://pubs.acs.org/doi/abs/10.1021/je60070a011