Our Zssential Formula provides a combination of protein sources across the board to maximize the nutritional benefits that each type of protein has to offer. It brings together red meat, poultry, and fish to create a complete food for your dog. In addition to a wide variety of vitamins and minerals, Zssential also provides a nutritionally correct ratio of fruits and vegetables that rounds out the recipe with powerful antioxidants and fiber-rich low-glycemic carbohydrates. Zignature Zssential® Formula – Learned from Nature, Crafted to Perfection.