In Part 1 of this series of articles on the Science behind the Tummyrite™ range of supplementary products for birds. I outlined the overall objectives of the Tummyrite™ product and its origins, and why such a product is needed for the effective care and feeding of captive birds. In this part, part 2, I discuss in more depth the science behind achieving objective 1 through the use of Tummyrite™ and Tummyrite +Plus™.
OBJECTIVE 1 - To improve the digestibility and utilisation of the main components of the food of graniverous birds
The main food components of birds are:
- Carbohydrates (sugar, starch and dietary fibres)
- Protein (amino acids)
- Fats (fatty acids)
These food components (most are delivered in the form of grain and grass seeds) are digested in the bird’s gastrointestinal tract (GIT) using its own internal enzyme system. Other enzymes also come from the food itself and also by the action of the micro-flora of the GIT. However not all food components that are ingested can be digested by the bird’s enzyme system. Some food components (some dietary fibres) can act in an adverse way limiting the uptake of nutrients (amino acids, vitamins, trace minerals) from the GIT and can have a significant anti-nutritive effect preventing the proper digestion of food.
Components such as the soluble non-starch polysaccharides (NSP) are notorious for forming a viscous gel-like slurry in the digestive tract which impede nutrient absorption and reduce dietary metabolisable energy utilisation.
The following diagram shows a broad classification of carbohydrates present in plant materials. Carbohydrates are a complex group of molecular compounds linked in various ways.
The hexose sugars play a major role in the nutrition in birds. The three hexoses that are nutritionally and metabolically the most important are glucose, fructose and galactose. Glucose is the end product of starch digestion and glycogen hydrolysis in the body, and it is the form in which carbohydrate circulates in the bloodstream. Sucrose (cane sugar) is a disaccharide made up of a molecule of glucose and a molecule of fructose. Fructose is very sweet and goes to fat metabolism. Galactose is not found in a free form in foods but forms part of the disaccharide lactose (milk sugar) which is not digested very well as birds do not possess the lactase enzyme and so are unable to digest lactose (Kleyn, 2013).
The two main NSP in grain are Xylans and the β-Glucans which occur in all grain species, and β-glucans which occur predominantly in small grains (wheat, oats and barley). External Xylanases (cellulases) are enzymes widely used to breakdown the arabinoxylans particularly prevalent in wheat and its by-products. External β-glucanase enzymes breakdown the β-glucans that are present in barley, oats and their by-products. The net effect of adding these exogenous enzymes to bird foods is that they reduce, if not eliminate, the anti-nutritive effects of these NSPs. Viscosity of the GIT content is reduced considerably allowing for improved nutrient absorption.
Grains fed to Passerine and Psittacine birds, such as millets, grass seeds and oats, contain some level of NSPs. These grains can constitute up to 60% to 70% or more of the bird’s daily diet. The efficient utilisation of these grains can benefit considerably from the addition of exogenous enzymes to the bird’s diet. TUMMYRITE™ contains a multi-enzyme product, including Xylanase, β-glucanase and other critical enzymes to assist in the digestion of these grains by breaking down the anti-nutritive xylans and β-glucans. The inclusion of carbohydrases, predominantly xylanase in wheat based diets, has been practiced routinely for the last three decades in the commercial Poultry Industries.
Cereal grains can be classified into two major categories according to their content of soluble NSPs, (Choct, 2007).
- Viscous cereals ( wheat, barley, oats, rye, triticale)
- Non-viscous cereals (corn, sorghum, millets and rice)
The significance of this classification rests on the pretext that increased digesta viscosity impairs nutrition digestion and absorption in poultry and other birds. The detrimental effects of NSP interact with the microflora in the gut and also alter the physiology and morphology of the digestive tract. The addition of specific enzymes to cleave and breakdown these NSP in the gut can eliminate their anti-nutritional properties. (Choct, 2007).
The hidden benefits of using enzymes in birds, such as the glycanases, fed viscous cereals include reduction in the output of manure containing large amounts of undigested nutrients, alleviation of problems associated with wet droppings, such as the increase incidence of dirty eggs in breeding birds, increased gas production (i.e. ammonia) and increase fly and rodent populations in aviaries (Choct, 2007).
In addition to the grains there are other types of feed ingredients which also contain NSP. Ingredients such as vegetable protein meals and seeds (Niger, Canola), cereal by-products which are usually added in seed mixtures, soft foods and starter feeds for young birds will obtain the benefit from exogenous enzyme addition. Additional enzymes are added also assist in the digestion of other components (protein, phytate) found in a range of feed ingredients fed to birds.
A complete list of enzymes (and carbohydrates/food component they effect) included in Tummyrite™ are:
- Xylanase (Arabinoxylans)
- Cellulase (Cellulose)
- Βeta-Glucanase (β-glucans)
- Mannanase (Mannans, Galactomannans)
- α-amylase (Starches)
- Phytase (Phytate Phosphorus)
- Protease (Proteins)