Energy and protein value of French low glucosinolate dehulled rapeseed oil-meal in pigs. Comparison with a normal commercial rapeseed oil-meal

Many studies carried out in France the last few years have shown that incorporation of large amounts of peas (30 p. 100 and more) in growing pig diets generally leads to a lower performance. Two successive experiments were made with 48 and 60 fattening pigs, respectively, kept in individual pens and with a live weight of 25-28 to 100 kg, in order to study : - the possibilities of incorporating a very high level of peas (40 p. 100) as only source of supplementary protein to simplified diets based on maize (trials 1 and 2) ; - the effects of L-tryptophan supplementation of diets based on peas : 0.03 p. 100 during the growing period only (trial 1) or 0.05 p. 100 during the whole fattening period (trial 2) ; - combinations of peas (30 or 40 p. 100) with a lucerne protein concentrate (10 or 5 p. 100) used as natural source of tryptophan (trial 2). feed intake of the control group during the finishing period. Results of both trials clearly indicate the role of tryptophan as first limiting factor in diets containing a high proportion of peas and point out the possibilities of using several protein sources of metropolitan origin to totally replace soybean in growing pig diets. A digestibility trial was made to estimate the energy and protein value of 3 types of rapeseed oil-meals exhibiting the following characteristics (expressed in percent of dry matter) : p. 100 for the commercial normal rapeseed oil-meal, 79.7 p. 100 for the normal French Zerothio and 88.1 p. 100 for the dehulled French Zerothio. Our results showed that the apparent protein digestibility coefficient of the French low glucosinolate rapeseed oil-meal was improved by 5 p. 100 as compared to the normal commercial rapeseed oil-meal, but the most significant result was the large improvement of the nutritional value of the French low glucosinolate dehulled rapeseed oil-meal (20 p. 100 for digestible energy and 15 p. 100 for protein A.D.C. mainly due to a reduction by 8.5 points of its crude fibre content as compared to normal rapeseed oil-meal. Two experiments were made in young piglets of 8.4 to 23 kg and in bacon pigs of 26.3 to 104 kg in order to study the effect of relatively low levels in incorporation of white soft lupin of the variety Kalina. The maximum level was 10 points for piglets and 15 points for bacon pigs. In piglets, utilization of lupin in diets offered as a meal containing 3 150-3 200 kcal D.E. and supplying 360 g lysine for 1 000 kcal digestible energy did not allow to reach the performance obtained with the control diet. An almost linear decrease in the feed intake ranging around 15 p. 100, was observed with the level of 10 points lupin. Growth rates were reduced less than proportional to the levels of feed intake since the feed conversion ratio was slightly improved by the presence of lupin.