As the search for alternative sources of energy for non ruminants continues, this review was undertaken to examine the potential value of cassava (Manihot utilissima Pohl.), sweet potato (Ipomea batatas Poir.), cocoyam (Xanthosoma sagittifolium Schott.) and their by-products as dietary supplements for non ruminants. Studies on these roots and tubers showed that, on a dry-weight basis, contained 2.0 -7.9% crude protein, 0.3 -3.1% crude fib re and 72.4 -77.9% starch. The practical use of these roots and tubers in non ruminant feeds is generally low. Th is level of utilizat ion is attributed to the low protein and dry matter and the potentially to xic cyanogenic glycosides in fresh cassava and irritating substance in cocoyam. Processing techniques such as fermentation, soaking, boiling, ensiling and sun-drying are adopted to remove the deleterious substances, and effects on animals. The co mparable performance of pigs and poultry fed vary ing levels of roots and tubers and their by-products with those maintained on maize showed that they can be used as substitutes in non-ru minants diets at certain levels without detrimental effects. To achieve increase in the use of these root crops and their by-products for maize replacement in intensive non-ruminant production systems, adequate protein supplementation and proper processing are essential.

A study was carried out on fish oil, two terrestrial animal fats (lard and chicken fat) and eight vegetable oils (palm kernel, sheabutter, soybean, palm, coconut, sunflower, groundnut and melon seed oils) to investigate their chemical and quality characteristics and the possibility of using them as alternative lipids in aquafeed. The results showed that the peroxide value of lard was significantly (P < 0.05) higher than values obtained in the other vegetable oils and animal fat sources; acid values of the oils ranged from 1.38 in coconut oil to 14.04 NaOH/g in palm kernel oil and were significantly different; the iodine value of sunflower oil, fish oil and soybean oil were comparable and higher, while a lower value that was not significantly different were observed in groundnut oil, coconut oil and melon seed oil. Thiobarbituric acid reactive substances of the oils were significantly different and showed low concentrations. The main fatty acids predominating in terms of relative abundance in the vegetable oils and animal fats examined are Lauric, palmitic, oleic and linoleic acids. Substantial levels of n-3 PUFA was observed in soybean oil and groundnut oil. The soybean oil and groundnut oil are exceptional high in the n-3 fatty acid content of the 18:3n-3 among the vegetable oils and would be a good lipid sources for tropical freshwater fishes.

β‐xylanase addition improved apparent nitrogen and fibre absorption as well as feed transit time. Up to 150 g kg−1 boiled castor seed meal could be incorporated into pullet chick diets without any adverse effect on growth performance or blood constituents. Copyright © 2006 John Wiley & Sons, Ltd