Determination of, and Factors Affecting Nutrient Digestibility and Nutritive Value of 'Lupinus angustifolius' (cv. Gungurru) for Growing Pigs

Abstract

Lupins are a commonly used dietary feedstuff for pig production in Australia. They are high in energy and do not contain any known anti nutritional factors. The current practice of the feedmilling industry is to coarsely crush lupins, and in some cases the seed-coat is also removed prior to incorporation in stockfeed. Despite widespread acceptance of lupins as a feedstuff, there is wide variability reported in the literature for its digestible nutrient content and this makes assigning a precise nutritive value to them for diet formulation problematical. Work by Fernandez and Batterham (1992) and Batterham (unpublished), reported the possibility of an interaction between dietary energy source and the growth (empty body weight gain) performance of pigs offered diets containing lupins and kernels relative to pigs offered a soyabean meal diet of equivalent digestible nutrient intake. The current series of experiments were somewhat similar to those of Fernandez and Batterham (1992) and Batterham (unpublished) as it was necessary to determine whether such an interaction could be repeated. On this basis, four experiments were designed in which the performance of pigs offered both lupin-seed meal (lupins) and dehulled lupin-seed meal (kernels) could be compared with pigs offered soyabean meal in sucrose- and wheat-based diets. ... In summary, dietary energy source was found to significantly influence both retention of ileal digestible lysine, and determination of DE. The important implication of these findings are that in practice the use of lupins in wheat-based diets will, produce a lower level of pig performance than soyabean diets of equivalent digestible nutrient density, despite indications to the contrary using sucrose-based diets.