| Abstract | Sixty-four pigs, fed ad libitum from 24 to 91 kg liveweight, were used to compare the effects upon live performance, carcass measurements and backfat composition of including rapeseed meal, derived from B. campestris (cv. Span) or B. napus (cv. Target), or ground Span rapeseed as 10% of diets based on barley with meatmeal or soybean meal as the source of supplementary protein. A further 32 pigs were similarly fed on barley/meatmeal diets containing 0, 4, 8 or 12% of the ground Span rapeseed. Pigs receiving diets containing Span or Target rapeseed meals grew 5 and 15%, respectively, slower than those fed the control diets (0.75 kg/day). The feed:gain ratio was improved with the Span diets (3.77 vs. 3.87) but not with the Target diets (3.97). Estimates of carcass quality also suggested that the meal from Span was superior. Backfat composition was similar on all rapeseed meal diets. Increasing the level of dietary rapeseed tended to reduce the growth rate by up to 11%, but improved the feed:gain ratio up to 8%, and the carcass quality. At levels exceeding 4% there was a marked increase in the degree of unsaturation of the backfat, reflecting increased proportions of linoleic and linolenic acids. |
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