الفهرس 
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Abstract
Lipids constitute the main energetic source for animal diets and they have the highest caloric value among all the nutrients (Baiao and Lara, 2005)(I). Besides supplying energy, the addition of fat to animal diets improves the absorption of fat-soluble vitamins, decreases pulverulence, increases diet palatability, and the efficiency of utilization of the consumed energy. Furthermore, it reduces the rate of food passage through the gastrointestinal tract, which allows a better absorption of all nutrients present in the diet (Baiao and Lara, 2005)(1). The energetic value of oils and fats depends on the following: the length of the carbonic chain, the number of double bonds, the presence or absence of ester bonds (triglycerides or free fatty acids), the specific arrangements of the saturated and unsaturated fatty acids on the glycerol backbone, the composition of the free fatty acid, the composition of the diet, the quantity and the type of the triglycerides supplemented in the diet, the intestinal flora, the sex and the age of the animals (Baiao and Lara, 2005)(1\
Feeding fat-added diets to farm animals can confer several economic advantages and is becoming a common practice. Several experiments have been conducted to assess the influence of dietary fat on growth and feed utilization in rabbits (Fernandez and Fraga,
/o\
1992/ . There is little evidence of any special problems associated with feeding fat to rabbits. Consequently, fat may be a useful material to extend the range of energy levels recommended in rabbits. Fat included in monogastric diets is partially incorporated into the animal’s polar and neutral lipids, thus leading to different lipid compositional characteristics (Cobos et al., 1993)(3>.
Oxidation of lipids in food has received considerable attention because of possible adverse health effects related to consumption of oxidized lipids. The rate of lipid oxidation in meat systems depends on a number of factors, including the polyunsaturated fatty acid content of muscle and the presence of antioxidants such as a-tocopherol. Phospholipids present in the membranes are believed to play a key role in the initial development of oxidation (Lopez-Bote et al., 1997)(4).Lipid peroxidation refers to the oxidative degradation of lipids. It is the process in which free radicals ”steal” electrons from the lipids in cell membranes, resulting in cell damage. This process proceeds by a free radical chain reaction mechanism. It most often affects polyunsaturated fatty acids, because they contain multiple double bonds in between which lie methylene -CH2- groups that possess especially reactive hydrogens. As with any radical reaction, the reaction consists of three major steps: initiation, propagation, and termination (Muller et al., 2007)(5).
The inclusion of fats in diets for rabbits has effects upon the productivity and development of the animal that determine the interest in their use. Several studies (reviewed by Femandez-Carmona et al., 2000)(6) have demonstrated that the tolerance of these animals to dietary fats is high if the diets are of good quality, since they improve feed palatability and are well digested by the animal. It allows the energy content of the diet to be increased without reducing its level of fibre (Femandez-Carmona et al., 2000)(6), a highly important nutrient for the correct transit and digestive functioning in rabbit, resulting generally in a reduction of production costs. Moreover, it is well known that the high mortality percentages in rabbits in high-temperature environments are due to the weakness of rabbits against the heat stress. In order to aid the rabbits to withstand the effects of heat stress, one should consider carbohydrates and lipids as sources of energy for them in terms of attempting to