C.M. SHAYO¹, B. OGLE² and P UDÉN²

¹Zonal Research and Training Centre, Livestock Production Research Institute, Mpwapwa, Tanzania
²Department of Animal Nutrition and Management, Swedish University of Agricultural Sciences, Uppsala, Sweden

Abstract

A study was made of the chemical composition and in vitro and in sacco digestibility of water melon (Citrullus vulgaris) seeds, Acacia tortilis pods and sunflower-seed cake and their effect on the rumen environment of a steer fed a basal diet of Cenchrus ciliaris hay.
Water melon seeds contained 15.5–18.5% crude protein (CP) and 24% ether extract (EE). Levels of soluble and condensed phenolics were negligible. CP level of Acacia seeds (18.6%) was higher than that of the empty pods (9.3%), the average CP content of the whole pod being 13.4%. Acacia seeds and empty pods had similar levels (41%) of soluble phenolics, while the level of condensed tannins was higher in the seeds [15 absorbance at 550 nm/g of neutral detergent fibre (abs/g NDF)] than in the empty pods (7.78 abs/g NDF). Similarly, the Acacia seeds had higher in vitro organic matter digestibility (86%) and total rumen degradable nutrients (82%) than the empty pods (60% and 66%, respectively). Rumen NH₃-N and pH levels were not affected by either water melon seed or Acacia pod supplementation.
The role of these supplements in cattle farming systems in central Tanzania is discussed.