The equine is a non herbivore ruminant that is able to fully provide its nutritional need by the grass intake. Equines show the cecum and colon region plenty developed as their principal fermentation site. Such process either happens in the non glandular stomach region, but the volatile fatty acids production is inferior then the production in the - hindgut. To meet the optimum use of the mix of ingredients, and to avoid excess there are harmful to the equine metabolism, it is important to know the ingredients digestion site. The recent carbohydrate fragmentation's study, even if it's not totally adapted to the equine metabolism and physiology, can provide information regarding the different carbohydrate fraction, that lead to infer data about the energy produced by each fraction. Feeding equines in pasture, or with hays or forage fed is essential to keep the digestive tract in activity and healthy, and to guarantee such condition, it necessary to provide at least 12% of NDF. Nowadays, ingredients such as citric pulp, beet pulp, soybean hulls, are used in the formulations to increase the energy's availability. The above mentioned ingredients, that present fast and easy fermentation, are a safe alternative to increase the energetic concentration in the equine diet, due to the decrease of the starch supply in such procedure. It's known that, with the increase in fibrous fed quality, higher amounts of soluble carbohydrates with fast fermentation are available along all equine digestive tract generating some metabolic disturbs such as laminits and insulin sensibility. With the correct equine pasture handling and the knowledge of the plant cycle it's possible to reduce such problems. The aim of this study is review the physiologic and metabolic action of different fibrous fraction in each digestive compartment tract of the equine diet, likewise to list the main studies of fibrous fed fractions with their fractions, which allow to suggest appropriate feed handling for equines.
equine; fiber; gastrintestinal tract; metabolism; nutrition
