Beet pulp, pasta, soybean oil, wheat middling, calcium carbonate, magnesium oxide, copper sulfate, iron sulfate, zinc oxide, choline (choline is a water-soluble nutrient) chloride, etc. are often the ingredients in case of vegetarian based diet items offered to the pet animals like dogs.
Taurine is one of the essential ingredients for the dog’s nutrition.
Likewise, in the case of dogs feed with frozen fish items, the vitamin called thiamine needs to be supplemented as an ingredient.
Many premium types of dog food preparations contain essential fatty acids, carbohydrates with adequate fiber contents, vitamins like A, D, E and B complex vitamins.
Furthermore, minerals are an essential ingredient, like zinc for skin health status and calcium for bone growth and muscle tone.
They should be enriched in these food items.
However, the cost of those food preparations is comparatively more expensive than the food preparations with general ingredients.
Though it may be better for your Shih Tzu’s health.