Gastrointestinal Nematodiasis in Ruminants: Nutritional Consequences and Ameliorations

Gastrointestinal (GI) parasitism is a potent threat to overall economy of animal rearing as it affects animal production drastically. GI parasites reduce nutrient availability to the host through both reduction in voluntary feed intake and/or reduction in the efficiency of absorbed nutrients. The extent of impairment by parasite is influenced by the level of larval challenge, species of worms, host's previous infection of parasites, its age and breed. Subclinical infection of GI nematodes may cause only transient or no effect on apparent digestibility of crude protein or energy but extensive damage of the GI tract during acute phase of infection significantly affects the digestion and absorption of nutrients especially proteins. Nutritional modulation through supplying of protein, energy and minerals can help to improve the immunity status of the body for resistance and resilience against GI parasites. Plants containing condensed tannins may be beneficial for controlling GI parasite infections as low amount of condensed tannins have protective action against proteins, improve immunity and antioxidant status of animals and direct toxic effect against worms.