Slider.wholeNumbers

public bool wholeNumbers ;

Description

Should the value only be allowed to be whole numbers?

using UnityEngine;
using System.Collections;
using UnityEngine.UI; // Required when Using UI elements.

public class Example : MonoBehaviour
{
    public Slider mainSlider;

    public void Start()
    {
        //sets the slider's value to accept whole numbers only.
        mainSlider.wholeNumbers = true;
    }
}