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Abstract
In Egypt, about of 15.2 million tons of agricultural lignocelleuletic wastes are resulted annually (Hathout and El-Nouby, 1990). Approximately two thirds of the crops residues are burned or wasted, which lead to environmental pollution causing health hazards. Rice and corn are main summer crops in Egypt. The average production of rice straw (RS) and corn stalks amounts annually more than 5.58 million tons. The annual amounts of peanut hay (PH) were estimated to be about 34500 metric tons of stalks and hay produced from 3200 feddans of peanut (Statistics of Agricultural Economic Research Institute, 1993).
The low quality roughage is mainly characterized by a high content of crude fiber and low nitrogen content and varying extent of minerals and vitamins. It is evident from the literature that forage or roughage alone cannot supply sufficient energy especially for high producing animals, therefore concentrate supplementation is always needed for maximizing intake and consequently improving overall performance of ruminant animals. Moreover, utilization of diets by ruminants seem to be markedly affected by the type of roughage being fed which is reflected on animal performance and health.
The poor quality roughage can be treated with different methods (mechanical, chemical or microbiological) and / or supplemented with appropriate supplements (energy, protein, minerals, vitamins and feed additives) to enrich its feeding value.
One of the best methods to reduce feed costs is through the use of feed additives. Their primary effects are to improve feed efficiency and/or daily gain (Brandt et al., 1991), or by change rumen fermentation particularly by increasing bacteria activity which in turn leads to increase degradability of forage and flow rate of microbial protein from rumen (Wallace and Newbold, 1992).
This study aimed to investigate the ability of two types of growth