how to change attribute in descendant?

[novice2]

Hello.
I need declare some base class A with general functionality, then
more special descendants AA and AB.
"A" class have some fields, that i don't want "show", i make it
protected. Then in some descendant i need "open" it. I need change
it from "protected" to "public".
In Delphi i just redeclare it in descendant, but in "public"
section. Delphi allow change visibility of class members from low
to higher. Private->protected->public.

How i can do this in D?

/********* test.d ********/

import std.stdio;

//base class with general code

abstract class Animal
{
  protected int legsCount;

  protected int poisonStrength;

  public bool canWalk()
  {
    return legsCount>0;
  }

  public bool canKill()
  {
    return poisonStrength>0;
  }
}


//tiger = animal with legs without poison

class Tiger : Animal
{
  public int legsCount;
}


//snake = animal without legs with poison

class Snake : Animal
{
  public int poisonStrength;
}


void main()
{
  Tiger t = new Tiger;
  t.legsCount = 4;
  writefln("tiger: legs=%d, canWalk=%d, canKill=%d", t.legsCount,
t.canWalk, t.canKill);

  Snake s = new Snake;
  s.poisonStrength = 100;
  writefln("snake: poison=%d, canWalk=%d, canKill=%d",
s.poisonStrength, s.canWalk, s.canKill);
}

output:
tiger: legs=4, canWalk=0, canKill=0
snake: poison=100, canWalk=0, canKill=0