Effects of raw and heat-treated bambara groundnut (Vigna subterranea) on the performance and body composition of growing broiler chicks.

Abstract

Bambara groundnut (Vigna subterannea)--a leguminous root nut, which grows in the tropics and subtropics--was used in an experiment to test its effect on the performance of growing broiler chicks. Performance was measured by monitoring growth, measuring nutrients and energy balances and also by determining nutrient accretion. Twelve-day old broiler chicks, kept in individual metabolic cages, were used in an experiment in which birds were equally allotted (n = 10) into a control (fed high performance diet made up principally of wheat and soybean meal) and 6 test groups fed diets containing 19, 76 and 95% raw or autoclaved bambara groundnuts. All diets were similar in energy, nitrogen and total lipid contents. Diets were also balanced for amino acids, vitamins and minerals in accordance to the specific requirements of the birds. Feed and water were provided ad libitum. Growth performance was monitored over 15 days. Nutrient and energy balances were measured by use of TiO2 as marker. The comparative slaughter technique was implored for the determination of energy and nutrient accretion. The results showed that the level of raw or autoclaved bambara had no significant influence on feed intake. Increasing the bambara level in the diets caused a general linear drop in the performance of the broilers. However, with up to 95% bambara in the diet, the general performance was still above 75% compared to the control. Increasing levels of bambara groundnut caused a decrease in the metabolizability of energy and efficiency of utilisation of ME for BWG. The animals retained more water with increasing levels of raw bambara in the diets while autoclaving increased their DM content to levels comparable to the control. The protein composition of gain was comparable at all levels of inclusion. In general autoclaving improved the performance of bambara.