Canola meal as a protein source for growing pigs. (Abstract)

Abstract

194 Canola Meal as a Protein Source for Growing Pigs J.L. Ranford, B.P. Mullan, J.R. Pluske, J. Allen and J. Hooper Animal Industries, Western Australian Department of Agriculture, Perth 6 15 1 New cultivars of Canola seed with low erucic acid and glucosinolate levels have resulted in Canadian pig producers replacing up to 75% (grower) and 100% (finisher) of soyabean meal with Canola meal (CM) in their diets. While there has been some suggestion of reductions in feed intake, no significant loss of performance and carcase quality has been noted (Bell, 1993). With Australia's increasing production of Canola and an anticipated reduction in its price, the suitability of CM as a substitute for one of our major protein sources for pigs, Lupins (L), is worth investigating. This experiment tested the hypothesis that CM can be successfully substituted for L in diets for growing and fmishing pigs without detriment to performance or carcase quality. Sixty pigs (Large White ' Landrace) with an initial liveweight (LW) of 20 k 0.19kg were assigned to diets (6 entire males & 6 females/diet) containing varying proportions of CM:L (0:25, 5:20, 10:15, 15:lO & 20:5%). Protein adequate diets for growers and fmishers were formulated to be isocaloric (14 and 13.5MJ DE/kg respectively) and isonitrogenous (0.65 and 0.55Av Lys/MJ DE respectively). Pigs were fed at three times their maintenance requirement (i.e. M = 0.46W'.75 MJ ME/day) and accommodated in siglespaced, fully-slatted pens. Pigs werre slaughtered at 90kg LW and measurements of carcase weight, depth of backfat, eye muscle area and thyroid weight (g) made. The proportion of CM in the diet had no significant effect on either average daily gain (ADG), feed:gain, dressing %, depth of backfat or eye muscle area. Despite a trend for ADG to decrease and backfat to increase (793 vs 763g/d and 13.6 vs 14.4mm, respectively) when diets contained any amount of CM, these differences were non significant. There were no sex ' treatment effects but entire males grew faster, had a lower feed:gain and lower dressing % than their female counterparts (PcO.05). The thyroid glands of pigs fed the higher levels of CM were larger than those fed diets containing 10% or less CM (PcO.05) and this was attributed to the 15: 10 and 20:5 diets containing 2.3 and 3.0&l/g of glucosinolates, respectively. Canola meal can successfully replace Lupins in grower and fmisher diets at inclusion levels up to 20% without any significant effects on either performance or carcase quality, but the potential deleterious effects of glucosinolates when pigs are fed ad libitum warrants further investigation. Reference Bell, J.M. (1993). Factors affecting the nutritional value of canola meal. Canadian Journal of Animal Science, 73: 679-697. Table 1 The influence of inclusion level (%) of CM and L on the performance and car-case characteristics of pigs from 20 to 90 kg LW Recent Advances in Animal Nutrition in Australia: Jury 199.5 University of New England, Armidale NSW 23.51, Australia