A New And Simple Technology For The Conversion Of Poultry Manure To Animal Protein Ingredient By Composting For Small Holder Farms In Nigeria

摘要

Excreta of poultry birds kept in confinement has hitherto been used primarily as organic fertilizer. However, land shortage especially in Southern Nigeria where poultry production is predominant has inhibited returning the progressively increasing volume of manure to the soil. There is therefore the need to develop alternative means of converting poultry excreta into useful product based on the principle of composting in order to eliminate the problem of environmental hazard, which the waste presently constitutes on poultry farms. The process in this study involved the construction of a simple maggotry which consisted of 2 vats made with concrete blocks with each of the vats having a hole about 4 inches in diameter behind and covered with a wire mesh to allow water through but not solid materials. Each of the vats had a tap leading water into it from the top. A shed of wood and corrugated iron sheets was constructed over the vats to provide aeration and shade. The vats were three-quarter filled with poultry excreta and exposed to flies, the holes behind having been blocked to prevent run off of the water. Vegetable oil was added at the rate of 2.5g kg~(-1). The manure was constantly moistened to prevent drying up and death of the larvae. The compost material was then left for about 3 days before the larvae were harvested by floatation, washed several times, rinsed free of debris and dipped in hot water to kill them, sundried and then milled. Chemical analysis of the larvae meal showed that it haddry matter content of 870g kg~(-1), moisture of 130g kg~(-1), ash of 80g kg~(-1), crude fiber of 40 g kg~(-1), fat of 100g kg~(-1) and crude protein of 640g kg~(-1). Its mineral contents were as follows; P, 1.53mg; Na, 0.33mg; K, 1.00mg; Ca, 0.16mg; Mg,0.39mg; Mn, 256ppm; Fe, 1244ppm; Cu, 61.5ppm and Zn, 285ppm. Its chemical and amino acid compositions are comparable to those of fishmeal, a major animal protein ingredient in livestock feeds in Nigeria. Thus through composting poultry excreta can be converted to larvae meal for feeding monogastric animals.