Use of grain-free diets in dog and cat nutrition is not a new area in veterinary nutritionology any longer. However, in the United States and in Western countries application of grain-free pet food is quite popular, since presence of cereals in the diet worsens digestion, increases the risk of developing food allergy and other diseases of the gastrointestinal tract and metabolism, and decreases absorption and digestibility of nutrients [1].

It is known that dogs and cats do not need a large amount of easily digestible carbohydrates, because by their nature they are carnivores. At the same time, rations for these animals must include an appropriate level of protein and fiber, which contributes to the function of the intestine and normal formation of feces. For example, most of the world's best-known non-grain diets, in addition to high-quality animal protein, contain components such as fruit and vegetables - a source of vitamins and fiber [2]. The modern Орtimeal grain-free diets are no exception: their qualitative and quantitative composition is balanced by the content of nutrients, vitamins, and minerals required for a dog and a cat. So, let us consider individual components of grain-free diets for a deeper and more professional understanding of their quality, wholesomeness, and safety.

The key source of protein in Орtimeal grain-free rations for dogs and cats is duck, turkey, lamb meat, salmon, etc. These meat types have an appropriate amino acid composition, so Орtimeal grain-free diets can be used as an exclusionary diet for dogs and cats.

Another important point regarding protein content when developing Орtimeal grain-free diets is that they do not contain gluten - the vegetable protein that is part of cereals (most present in wheat, barley, and rye) and may, due to some amino acids in its composition, cause severe disorders of the bowel function. In dogs and cats, one of causes of enteropathies with protein loss is gluten intolerance [4]. Meat products and vegetables do not contain gluten. Therefore, absence of gluten-free components in rations is important for use in daily diets, and for the animals that have the history of chronic inflammatory bowel diseases prescription of grain-free diets may be an alternative feeding option reducing the risk of exacerbations.

The key source of easily digestible carbohydrates in grain-free Optimeal diets is potato and tapioca. These vegetables contain starch, which is a source of energy, but its amount is balanced in the formulation of daily dietary amounts. For dogs and especially for cats, easily digestible carbohydrates make it possible to use their high-energy potential and are easily digested and absorbed. But it is known that excess of starch in the diet may cause digestive disorders in the small intestine, so their amount should not exceed 12 g/kg for dogs and 5 g/kg for cats [3] in rations.

More important for dogs' and cats' organism is sufficient content of vegetable fiber in their diets. In Optimeal grain-free rations, the key source of fiber is beet pulp, pumpkin, green peas, carrots, and flax seeds. Presence of sufficient amounts of vegetable fiber in the diet increases the volume of feces, their water content, adsorbs toxins, and normalizes intestinal motility [5]. Other important components of the diet are mannanoligosaccharides - prebiotics that can suppress the pathogenic microflora in the intestine and promote development of the normal flora, as well as reduce intensity of feces decay products formation in the intestine.

To maintain beauty and health of dogs and cats, Optimeal grain-free diets contain a natural extract of baker's yeast MacroGard - a source of β-glucan, omega-3 and omega-6 fatty acids (contained in salmon oil), as well as medicinal herbs - marigold, burdock root, chamomile flowers, nettle, thyme, and Borage oil. All these are an additional source of B vitamins and other beneficial medicinal substances that strengthen the immune system, improve the skin and hair, and activate digestion.

Thus, having analyzed the composition of Орtimeal grain-free rations, one could distinguish their specific dietary advantages:

• Орtimeal grain-free diets can be seen as more physiological than rations containing cereals, as the digestive system of dogs and cats is better suited to digesting and absorbing meat.

• Dogs and cats use animal protein as a source of energy and do not have a significant need for easily digestible carbohydrates contained in grains, so Орtimeal grain-free rations can be recommended for young and active animals, as well as those predisposed to obesity.

• Excessive animal protein in the diet is not always beneficial for a dog or cat, especially older ones, so the balanced Орtimeal rations with respect to content of animal proteins, fat, and carbohydrates, including fiber, turn out especially important.

• Орtimeal grain-free diets do not contain gluten - the vegetable protein that is contained in cereals, which completely excludes its negative impact on the digestive system of animals or its contribution into development of food allergy.

• Орtimeal grain-free rations contain high-quality vegetable ingredients (green peas, carrots, pumpkin, beets) as a source of fiber and water-soluble vitamins, which makes these diets unique to promote healthy digestion.

• Presence in Орtimeal grain-free diets of a combination of medicinal herbs (flax seed, burdock and althaea root, chamomile flowers, nettle, cassava, thyme) strengthens the immune system and prevents dysfunctions of the digestive system and metabolism.

• The combination of high-quality protein with unique substances improving digestion (mannanoligosaccharides, β-glucans) makes it possible to further support digestion of nutrients and promotes maintenance of the immune function of the intestine and protects it against irritation and damage.

Author: Morozenko D.V. , PhD in Veterinary, practicing doctor of veterinary medicine, gastroenterologist, clinic of veterinary medicine "PES+KOT",  Kharkiv

REFERENCES

1. Grain-free diets: An alternative option, but don’t dismiss the grains / Lisa M. Freeman, Cailin R. Heinze // Deciphering Fact from Function. – 2012. – N 4. – P. 1–4.

2. Alternative dietary fiber sources in companion animal nutrition / de Godoy M.R., Kerr K.R., Fahey G.C. // Nutrients. – 2013. – N 5(8). – P. 3099-3117.

3. Книга Waltham о кормлении домашних животных (WALTHAM Book of Pet Nutrition) / Под ред. А. Бургера. – М.: ПАЛЬМА Пресс, 2001. – 152 с.

4. Гастроэнтерология собак и кошек: руководство по клиническому питанию (Gastroenterology of dogs and cats: clinical nutrition guideline / Э. Спаркс, К. Жан-Филипп. – М.: Эксмо, 2014. – 200 с.

5. Influence of cellulose fibre length on faecal quality, mineral excretion and nutrient digestibility in cat / Prola L., Dobenecker B., Mussa P.P., Kienzle E. // J. Anim. Physiol. Anim. Nutr (Berl). – 2010. – N 94(3). – P. 362-367.