1.0 Introduction
The increasing demand for animal protein coupled with more stringent economic conditions have encouraged greater interest in fast growing animals with short generation interval. Poultry and pigs are the first choice but their production is more demanding because of the high cost of production and competition with man for feedstuffs. Fetuga (1997) reported on the disappointing rate and level of performance in the livestock industry in Nigeria. This he attributed, among other factors, to high cost of feeds arising largely from fluctuations in feed supplies, rising prices of ingredients, poor quality feeds, inefficiency in production and distribution in the feed industry.
Many investigators have suggested ways of increasing the low animal protein intake of Nigerians. One of the cheapest producers of meat that can easily fit into the wider segment of the population but which has been neglected in Nigeria is the rabbit. The rabbit has the ability to convert feedstuff such as forages, most agricultural by-products, kitchen waste etc that human being cannot consume directly into highly nutritious meat. Rabbits are highly prolific, cheap to feed because they can utilize roughage feeds, they have rapid growth rate, high dressing percentage, short gestation period and low purchasing price. However, efficient rabbit production is largely dependent upon adequate and correct nutrition (Standford 1979). There is no rabbit so good that poor nutrition will not ruin nor any bad one that good feeding will not improve.
A rabbit which is not well fed can not give its best, and when it is realised that the greatest cost of producing rabbits lies in the nutrition, correct feeding therefore becomes of utmost importance to the rabbit producer. The quantity of feed provided is important but the quality or type of feed is more important because poor nutrition result in slow growth rate, inefficient reproduction and predisposes the animals to diseases.
Aduku and Olukosi (1990) reported a digestible energy range of 10.00 − 10.46 MJ/Kg for optimum performance of rabbits in the tropics. The digestible energy (DE) level reported by these workers are, however, similar to digestible energy (DE) of 10.46 MJ/Kg recommended by NRC (1977) for growing rabbits in temperate zones. Aduku and Olukosi (1990) also reported a range of 2390-2500 K cal/Kg of energy and crude protein level of 12-17% for optimum performance of rabbits in the tropics. Fielding (1991) had reported a range of 16 − 18% crude protein (CP) as optimal for growing rabbits.
In recent years, there have been renewed interests in the use of non-conventional ingredients in feeds formulation for livestock. Standford (1979) reported that, there is a wide range of feedstuff on which rabbits can live on. Therefore, alternative feed sources need to be investigated such as, Moringa oleifera, the leaves of which have been used as animal feed in many places. Moringa oleifera leaves, stems, roots and other parts have been popularly used as animals feeds in countries such as Senegal, Niger, Kenya, Tanzania, Zimbabwe, Gambia, Malawi, India, Spain, USA and Germany etc (Fugile, 1999). However, it potentials as an animal feed supplement have not been properly documented in Nigeria.
Moringa oleifera is a multipurpose browse plant with useful characteristics. The leaves and green fresh pods are used as vegetable by man and are rich in carotene and ascorbic acid with a good profile of amino acids (Makkar and Becker 1996). It is also used as livestock feed and its twigs are reported to be very palatable to ruminants and have appreciable crude protein levels ranging from 26 − 27 percent (Sutherland et al 1990, Sarwatt et al 2002, Kimoro 2002).
Fuglie (1999) stated that the high bioavailability of Moringa oleifera leaves and stems make them an excellent feed for cattle, sheep, goats, pigs and rabbits. The leaves of Moringa oleifera are an excellent source of the sulphur containing amino acids, methionine and cysteine, which are often limiting in most feedstuff used for feeding animals (Maroyi, 2006). Moringa oleifera leaves have also been used as an alternative protein source for tilapia fish production (Becker et al, 2002).
Mathur (2006) indicated that cattle fed with the leaf and green stems of Moringa oleifera can increase milk production by 43 − 65% and increased daily weight gain in cattle by up to 32%. Onimisi et al (2007) indicated that Moringa oleifera leaf meal can be included up to 30% in rabbits diet without any adverse effect on the growth performance. Moringa oleifera can also be included up to 20% in the diets of laying birds without any adverse effect (Kakengi et al 2007). The authors went further to state that, the high pepsin and total soluble protein makes Moringa oleifera leaf meal a more suitable feedstuff to monogastric animals.
In most parts of Nigeria especially in the north, the fresh leaves of Moringa oleifera are used as vegetable, roots for medicinal purposes and stem/branches for demarcation of property, boundaries in farmland and in house fencing (Muyibi and Evison, 1994). The abundance of Moringa oleifera plant in most part of the country as natural pasture, is a good indication that the plant can be successfully used to reduce the problems of the short supply of protein sources currently being experienced by feed millers. Nigeria like many other developing countries is currently faced with the shortage and high cost of conventional feeds for poultry, rabbits and other livestock with protein sources of plants and animal origin constituting one of the greatest part of the cost.
Therefore, there is the need to investigate alternative feed source like Moringa oleifera to see to what extent it can supplement or completely replace plant proteins sources in animal feeds.
