DEHULLED PROTEIN-RICH RAPESEED MEAL AS A PROTEIN-SOURCE FOR EARLY WEANED PIGLETS

Dehulled protein-rich rapeseed meal (DPR-meal) was produced by aqueous enzymatic extraction. Based on chemical analyses and balance experiments with piglets, the nutritive value was determined. The dry matter of the DPR-meal contained 56% crude protein, 27% HCI-fat, 12% carbohydrates, 5% ash and 1 mumol g-1 glucosinolates. Four diets containing 0, 6, 12 and 18% DPR-meal were manufactured and tested in a balance trial as well as in two production trials with 4-week-old weaned piglets. In the balance trial, 16 pigs were reared in single cages and fed semi ad libitum. Each production trial was performed with 80 pigs, reared in pairs and fed ad libitum. The period of treatment lasted 4 weeks. Substitution of the highly digestible protein sources skim milk powder and fish meal with DPR-meal caused decreased digestibility of protein and energy with increasing dietary levels of DPR-meal. Deposited N and deposited N as a percentage of digested N were equal for the four diets. In addition, no negative effects on protein utilisation from the glucosinolates were observed. The decrease in digestibility of energy (r2 = 0.91) and protein (r2 = 0.90) correlated well with the insoluble dietary fibre (IDF) content. In the first production trial a significant decrease in voluntary feed intake and reduced growth rate (P less-than-or-equal-to 0.001) of the pigs with increasing levels of DPR-meal was observed. In the second production trial, in which flavouring (Flavodan SW-783) was added to the DPR-meal, the decrease in voluntary feed intake was almost halved and the growth rate was not significantly affected (P greater-than-or-equal-to 0.05). In both production trials the feed to gain ratio was unaffected by the level of DPR-meal in the diets.