This video will show you how to take salt, water, vegetables and turn them into probiotics that are great for gut health.
4 cups water for every 1 tbsp sea salt, add vegetable and allow to sit on counter for 5 days. Not only is it great for you but it's great for your dog too. Caution, only use those vegetables that are safe and recommended for your pet!

I used Dr. Judy Morgan's book on Nutrition for dogs as my source for reference and recommendations.