This paper discusses the composition and nutritional values of a limited number of materials of tropical or sub-tropical origin encountered in advisory work. These products have emerged in recent years chiefly as minor components of compounds and to a lesser extent as ‘straights’. These by-products are olive pulp, grape pulp pellets, grape seed meal, dried coffee residues, citrus pulp pellets, cocoa shell meal, extracted cocoa meal, shea-nut pellets and shea expeller meal, guar meal, illipe meal and cassava meal. Other foods such as cereal by-products and sugar cane molasses are discussed elsewhere, whilst materials that may originally have been by-products of oil extraction such as soya, ground nut and palm kernel, etc., are now such significant parts of the modern sophisticated feed compounding industry that it may be unfair to classify them as by-products in the usually accepted sense. In any case information on them is well documented and readily available and hence they will not be discussed here.
The by-products listed above form only a small proportion of the imported feeding stuffs bill but nevertheless can be of economic and nutritional significance in isolated circumstances. Some idea of their overall monetary significance is as follows. The total quantity of imported feeding stuffs other than cereals in 1977 was 1 495 973 tonnes. Of the above list of by-products, only olive pulp and grape residues are listed separately on official lists and each account for less than 1% of the total. Olive pulp imports were 33 457 tonnes and grape residues 11 276 tonnes. Undefined residues from oil extraction, which presumably includes some of the above listed products, amounted to 58 791 tonnes, whilst ‘Other products of vegetable origin’ would account for some other imported products totalling 45 013 tonnes.