Journal of Food, Agriculture & Environment, Vol.6 (3&4), July-October 2008 121 The use of Donryu rats as a model for the humans in the formulation of dietary protein F.A. Dawodu 1* and K.O. Ajanaku 2 1 Department of Chemistry (Industrial), University of Ibadan, Ibadan, Nigeria. 2 Department of Pure and Applied Chemistry, Ladoke Akintola University of Technology, Ogbomoso, Nigeria. *e-mail: fadawodu@yahoo.com Received 8 December 2007, accepted 22 March 2008. Abstract The effects of brewery spent grain formulated diet on the performance of Donryu rats were investigated. The rats were allocated into 6 dietary treatment groups of 6 rats each and fed with diet containing graded levels of BSG 0, 3, 6, 9, 12 and 100%. The experimental feeding lasted for fifteen days. The BSG formulated diet was found to have a positive effect on the growth performance of the rats up to levels of 12% including the control (0%). The histopathological evaluation shows that 3–9% BSG could be used as protein supplement in human foods. Key words: Brewery spent grains (BSG), dietary treatment, growth performance, histopathological evaluation. Introduction The making of beer generate by–products such as spent grains. Brewery spent grains (BSG) is a safe feed when it is used fresh or properly stored. It contains high protein of about 26–30% and crude fibre 12 . Wet spent grains spoil rather quickly and should be used fresh or stored in an airtight compartment. For longer storage, it may be ensiled in an airtight trench silo. Wet spent grain can be ensiled alone or in association with other feeding ingredients such as 2–3% molasses to ensure proper fermentation 8 . It can also be used with chopped root vegetable or legumes to feed domestic animals. BSG has received little attention as a marketable commodity. Its disposal is often a problem. Its present disposal methods are no longer sustainable for the environment with devastating level of pollution. Therefore, the BSG waste management problems require developing new ways to use the spent grains considering the pressure it puts on environment and our health. There has been various researches 1-3, 14 on alternate uses of brewery by–products and waste minimization from brewery processes. Most of these investigations were mainly on animal feed. There is also a growing interests in the use of BSG in human foods such as flower mixes, bread 4, 9, 10 and meat product 5 . However, not much has been studied in the area of histopathological effect in human foods when it is used as protein supplement. This study was to evaluate the effect of dietary BSG on the growth performance of Donryu rats and then use the results to formulate protein supplement for human’s free side effect on the physiological aspects of human body and also to increase resource utilization and eliminate pollution from these breweries spent grains. Materials and Methods Materials: Brewery spent grains (BSG) was obtained from the major breweries in Nigeria, namely; Nigerian Breweries Plc, Ibadan and Guinness Nigeria Ltd., Benin and Lagos. Maize, soyabean meal, wheat offal, fish meal, bone meal, salt, lysine, methionine, premix (Growers) and water were bought locally to prepare the rats feed. The Donryu rats were bought from Cocoa Research Institute of Nigeria (CRIN), Ibadan. Methods: The BSG sample was dried at 40°C for about 24 hours in an electric oven. The dried BSG was milled to increase the surface area. The moisture content, ash content, crude fat, carbohydrate, crude protein, crude fibre and the nitrogen-free extract of the BSG were determined (Tables 1 and 2). The BSG was mixed with rats feed at levels of 0, 3, 6, 9, 12 and 100%. The 0% was used as the control. The control diet had no addition of the formulated diet. The thirty six Donryu rats were allocated into six dietary treatment groups of 6 rats each and confined in individual cages during the experimental period. The cages were built for easy collection of the faeces and urine. The rats in the groups are four weeks old before the commencement of the experiments. The rats were weighed at the beginning of the experiment as zero day, fed according to their group levels and subsequently weighed at daily intervals throughout the 15 days experimental period. On the sixteenth day, the rats were slaughtered using cervical dislocation method of euthanasia. Their blood was collected into two heparinized tubes for haematological studies; one tube contained ethylenediaminetetraacetic acid (EDTA) with calcium serves as anticoagulant in the blood samples. This was used for plasma parameter analysis. The second tube, which did not contain EDTA, was used for blood enzyme analysis. The red blood cell (RBC) and white blood cell (WBC) counts were determined using Neubauer haemocytometer. Packed cell volume (PVC) was determined using haematocrit centrifuge. Haemoglobin was determined by cyanomethaemoglobin method (MCH), mean corpuscular haemoglobin (MCH) and mean corpuscular haemoglobin concentration (MCHC) were determined according www.world-food.net Journal of Food, Agriculture & Environment Vol.6 (3&4) : 121-123. 2008 WFL Publisher Science and Technology Meri-Rastilantie 3 C, FI-00980 Helsinki, Finland e-mail: info@world-food.net