Since, Avian influenza disease is widespread emergence in Egypt and worldwide. This disease has become a matter of significant reduction in rooster production and highly price of meat and fish. Urgent action is therefore required to solve the problems, including increasing rabbit's production. Rabbit meat is of high quality and safety. Rabbit is suitable to be raised for meat production due to its high feed conversion efficiency, high fecundity and short generation interval. Moreover, rabbits use protein more efficiently than broiler and up to 20% roughage can be included in their diet. In these circumstances, it is important to use non-traditional feeds in animal feeding have low coast and help to raise the product which decreases the marketing price of animal products. In Egypt, in general and the new reclaimed desert lands, in particular, there is a great shortage in animal feedstuffs particularly during summer season and autumn. Much of the rangelands in arid and semiarid regions are dominated by shrub vegetation that represents an important source of food for ruminants. With shortages of arable land, feed ingredients and water in many countries, rabbits can help in food production by conversion many agricultural byproducts into meat. Generally, there is no need to use prime forages for rabbit feeding, and there is no need to use grains that are fit for human consumption. The list of what ingredients can be incorporated into rabbit feed is enormous and growing continuously. There are large quantities of utilized inexpensive feed resources such as Acacia in the desert and newly reclaimed areas. This acacia is widely distributed in tropical and subtropical Africa from Egypt and Mauritania to South Africa. Some subspecies are widespread in Asia as far east as Burma. Acacia saligna is perennial legume shrubs that gives green forages around the year and grows in marshy areas near fresh and salt water on sandy soils. It is used for soil fixation, as a fuel, wood or fence plant and is available throughout the year. Acacia is also a fast growing species, which can maintain active growth during the dry season (Man et al., 1995; Hua and Bee-Lian, 2000). The green biomass yields in three harvests up to 16 months after planting was 20.7 tones / ha (Man et al., 1995). The content of CP in Acacia foliage is relatively high; around 170 g per kg DM, but the intake of Acacia by goats is low compared to other shrubs (Man et al., 1995; Duyen et al., 1996). Forbes et al. (1994) reported that acacia contain high concentrations of numerous amines and alkaloids. These compounds are characterized by the fact that they contain nitrogen and are to a greater or lesser extent toxic. It has been used for goat and sheep feeding in different research works. The information in the literature about including Acacia saligna in rabbit's nutrition is scant.
The susceptibility of rabbits to various infections diseases and high mortality of young rabbits after weaning, however, hinder the development of the rabbit industry. Weanling rabbits often suffer from diarrhoea, which is the major cause of their mortality. Coliform bacteria (mainly Esherichia coli) are normal inhabitants of the intestinal tract of many animal species. In the intestine of health rabbits their counts are low, 102 – 104 per g intestinal contents. In rabbits with enteritis, however, the concentration of E. coli exceeds 108 g (Cortez et al., 1992). Digestive problems caused by enteropathogenic E. coli strains are often responsible for high morbidity and mortality of young rabbits after weaning, and consequently for important economic losses in rabbit farms (Licois, 2004). Rabbit breeders widely use antibiotics to control enteritis infections. The use of antibiotics, however, is viewed critically in recent times. Some were banned totally; some received no renewal of their license as a measure of preventive consumer protection. There is a pressing need for harmless antimicrobial substances suitable for rabbits nowadays. Organic acids have been used for decades as food and feed preservatives. Some of them (formic, fumaric, citric) positively influence the growth and feed conversion ratio of piglets (Partanen and Mroz, 1999). Several studies report the inhibitory effect of organic acids against E. coli –formic and propionic acid (Cherrington et al., 1990), lactic acid (Dibner and Buttin, 2002) and medium-chain fatty acids (Marounek et al., 2003); in the latter studies the authors showed the antimicrobial effect of organic acids toward E. coli was pH-dependent. Many researchers reported the effectiveness of formic acid as antimold agent like Tzatzarakis (2000).