Problems with impaired appetite. Rumen – a natural source of bacteria, protozoa, and microorganisms necessary for proper gastrointestinal physiology. Stimulates intestinal peristalsis, increases appetite, and prevents the consumption of waste, animal excrement, and carrion. Brewers yeast – a natural probiotic, source of B vitamins, selenium, biotin, and macro and micronutrients, tones the digestive tract