Document Type : Original Article
Author
Animal & Poultry Production Department, Faculty of Technology & Development, Zagazig University,Zagazig, Egypt
Abstract
All animals protect themselves from invasion of microbes, parasites, fungi,viruses and any foreign molecules. This protective capacity is based on effective immune system which is considered an important factor for animal health.
Enteric diseases frequently occur in rabbits, more especially in young rabbits after weaning. These digestive troubles cause mortality and reduced growth rates with important economic losses.Antibiotics are frequently used to prevent or to treat such illness.Unfortunately, the long term and extensive use of antibiotics has led to appearance strains of bacteria resistant to the antibiotics and caused adverse effects on the consumer health. So, it is necessary to search about alternatives to antibiotics.
One of the possible preventive approaches is to improve the non-specific immunity resistance of rabbits through the improvement of nutrition.Nutrition is also an important factor for rabbits to deal with environmental and psychological stressors such as heat, cold and inappropriate husbandry practices.A number of micronutrients and feed additives have been shown to affect various aspects of immunity in rabbits. Insufficient contents of micronutrients in animal diets are related with low disease resistance. A balanced supply of micronutrients such as vitamins E, β- Carotenoids, Vitamin A, Vitamin C and the trace elements zinc (Zn), Copper (Cu), selenium (Se), Manganese (Mn), Cobalt (Co), Iron (Fe)isof great importance for proper functioning of host defense mechanism.Some feed additives such as probiotics, prebiotics, enzyme preparations and organic acids could improve the immune response and disease resistance in rabbits.
Nutrients have direct role on immunity as they serve as substrates and enzymes cofactors for cellular multiplication during immune response (phagocytes, lymphocytes)and for synthesis of effective molecules (antibody, complement, nitric oxide, lysozyme)or informant molecules (cytokines, inflammatory mediators; Klasing and Leshchinsky, 2000 ). Amino acids, fatty acids and glucose serve as susbtrates, while vitamins and minerals act as co-factors for enzymatic activities. Nutrients could also have an indirect effect on immune response by modifying the intra- and extra-cellular communication pathways (cytokines) or limiting undesirable effects of effective molecules. Finally, the immune system is also regulated by numerous hormones (gastrin-releasing peptide, GH, IGF1, insulin, thyroids hormones…) most of which are responsive to nutritional factors (glucose, protein/energy ratio).
The amount of studies done on the effect of nutrition on immune function in rabbits are very little, so it is difficult now to propose actual dietary values for stimulating the immune defense of rabbits. However, the nutritionists can use the available data of fiber, fats (namely the quantity and nature of fatty acids), vitamin E and selenium and the interaction between them to offer the most interesting in this concern. The work should concentrate on the rabbit at weaning time, because this is the most critical period for young rabbits to infect by digestive diseases.
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