Journal of Global Biosciences ISSN 2277-2367 Vol. 1, 2012, pp. 1-4 http://www.mutagens.co.in/jgb.html EVALUATION OF THE GROWTH PROMOTING EFFECT OF GARCINIA KOLA SEED IN GROWING RABBITS Iwuji, T.C. and U. Herbert Federal University of Technology, Owerri, Imo State, Nigeria. 1 Michael Okpara University of Agriculture, Umudike, Umuahia, Abia State, Nigeria. Abstract A total of 36 growing rabbits of about 3 months old were used in an experiment that lasted for 3 months; and evaluated the growth promoting effect of Garcinia kola on growing rabbits. Three experimental diets, T 1 , T 2 and T 3, containing 0 %, 2.5 % and 5 % of Garcinia kola seed meal, respectively, were formulated. Twelve rabbits were randomly assigned to each treatment diet and comprises of 3 replicates of 4 rabbits each. Daily feed intake was significantly (P<0.05) higher in animals receiving Garcinia kola seed meal than in animals on control diet. Body weight changes of the animals on T 2 were significantly (P<0.05) higher than those on T 3 , but not significantly (P>0.05) higher than those on T 1 . Feed conversion ratio was significantly (P<0.05) higher in T 3 than in T 1 and T 2 which were similar (P>0.05). The result of this experiment reveals that Garcinia kola seed can be used in the diet of growing rabbits at 2.5 % dietary level to enhance feed intake and weight gain, thereby promoting growth in growing rabbits without compromising feed efficiency. Keywords: Garcinia kola, growth promoter, growing rabbits. Introduction The incidence of residual effect in livestock products and the development of resistant strains of micro-organisms due to drug therapy have resulted in the search for natural substances that can effectively replace the functions of the drugs used in animal production [1]. Garcinia kola (bitter kola) is one of such natural substances being explored in the animal production industry in Nigeria. A detailed description and distribution of the Garcinia kola plant has been documented [2]. Studies with Garcinia kola revealed decreased weight gain and organ mass in rats, but with significant (P<0.05) increase in sperm count [3]. However, studies with broiler chicks revealed growth promoting effect of Garcinia kola seed powder, which is attributed to its antimicrobial property [4, 5]. The effect of dietary Garcinia kola on body weight, haematology and survival rate of pullet chicks revealed improved weight gain and proliferation of the white blood cells [4]. Garcinia kola possesses a protective effect against a variety of experimental hepatotoxins which may impair growth [6, 7]. Organ mass and histopathology studies with growing rats revealed that Garcinia kola extract induced a dose related decrease in size of organs without any microscopic alterations; however, high libido (sexual drive) was induced in the rats [8]. Improved semen characteristics and high libido in an experiment with matured rabbit bucks fed diets containing Garcinia kola seed meal has been reported [1]. In the quest to finding natural substances and alternatives to drugs in animal production, this study is therefore designed to evaluate the growth promoting effect of Garcinia kola seed in growing rabbits. Materials and methods This study lasted for 3 months and was carried out at Michael Okpara University of Agriculture, Umudike, Teaching and Research Farm (Rabbitry Unit). The University and the farm is located on an elevation of about 120m above sea level at latitude 5°21’ North and Longitude 7°29’ East. Umudike falls within the rainforest zone of Nigeria which is characterized by hot and humid climate. The mean annual rainfall is about 2177mm, mean annual relative humidity is about 90% and that of temperature is 22°c to 36°c depending on the season. Management of animals: A total of 36 growing rabbits of about 3 months old were used for this study. The hutches for the animals were thoroughly cleaned and disinfected. On arrival, the animals were given Piper dewormer and allowed one week to acclimatize to the environment before administering the experimental treatments. The animals were randomly assigned to 3 experimental diets, T 1 , T 2 and T 3, containing 0 %, 2.5 % and 5 % Garcinia kola seed meal, respectively. Each treatment had 12 rabbits (3 replicates of 4 rabbits each) with feed and water given ad libitum. Preparation of plant material: Nuts of Garcinia kola were purchased from “Afo Enyiogugu” market in Aboh Mbaise LGA,