Enzyme supplementation of lupin based diets for poultry
The aim of the four studies reported in this thesis was to evaluate the effects of the inclusion of lupins in the diets for broiler chicks, and to evaluate any effect of enzyme supplementation on performance of birds fed lupin-based diets. Five types of lupin were used in the studies. Two determinate cultivars of Lupinus albus, Lucyane and Ludet, and two dwarf cultivars of Lupinus albus, Luniverse and Lucille. One cultivar of L. luteus cv. Wodjil was also used. The nutritive value of the lupins was determined by two precision feeding studies. The value of including the lupins in diets for broilers was evaluated using two growth trails. One trial was conducted using birds grown from 7-28 days and the other using birds grown from 0-13 days. The use of sialic acid as a measure of endogenous losses was also investigated. Effects of the diets on microflora in the birds gastro-intestinal tract were determined using GC profiling of the caecal contents. The five lupin types used in the study had protein levels that were similar to soyabean meal. Results of all studies indicated that the different cultivars of lupin behaved very differently, and therefore need to be considered separately in terms of which enzyme to use and levels of supplementation. It cannot be assumed that all lupins will respond in the same way to enzyme supplementation. The results of both growth studies showed that the two types of lupin cultivar, determinate and dwarf, respond differently to enzyme supplementation. This is possibly due to the different routes of plant breeding. It was clear from the study that the effects of lupin inclusion, enzyme supplementation and the interactions between the two are very complex. Further investigations of the mechanisms behind the effects are recommended.