Rapeseed meal of low- and high-glucosinolate type fed to growing-finishing pigs

Authors

• Matti Näsi University of Helsinki, Department of Animal Husbandry SF-00710 HELSINKI
• Timo Alaviuhkola Agricultural Research Centre, Swine Research Station, SF-05840 HYVINKÄÄ
• Kaija Suomi Agricultural Research Centre, Swine Research Station, SF-05840 HYVINKÄÄ

DOI: https://doi.org/10.23986/afsci.72213

Abstract

The nutritive value of five lots of rapeseed meal (RSM) from Brassica campestris or B. napus with different levels of glucosinolates (GL) was investigated in a digestibility and balance trial with a 5 x 5 Latin square design and in a growth trial with 140 growing-finishing pigs. The RSM’s were prepared from the cultivars: Span-Torch, Sigga, Gulliver and Topas, and a heat-treated RSM was also studied, their total GL contents (µmol/g defatted meal) being 42, 11, 98, 27 and 8, respectively. Cv. Sigga had yellow hulls and a lower ADF content than the other cultivars. The hat-treated RSM had a reduced lysine content. There were no significant (P > 0.05) differences in organic matter or crude protein digestibilities between the RSM’s with different GL levels or the RSM’s prepared from B. campestris and B. napus, when RSM was used as the only protein supplement at a level of 20—25 % in a barley-based diet. Heat treatment reduced the organic matter and crude protein digestibilities (P < 0.01). Nitrogen retention and protein utilization were lower (P < 0.01) on the diet supplemented with heat-treated RSM than on the diets with the other RSM’s but otherwise there were no significant differences between them (P > 0.05). In the growth trial supplementation with HGL-RSM Gulliver (14 % in diet) caused some palatability problems and this led to reduced performance (P < 0.05), but there were no differences between the other groups receiving 14—15 % RSM and the SBM control group (P > 0.05). The carcass quality was similar in all the groups. The weight of the thyroid gland was higher in the pigs receiving RSM than in the SBM controls, by 6—57 % (P < 0.05). In the present study a fairly high RSM supplements from cultivars with a moderate high GL content could be used in the diet of growing pigs without impairing their performance, when the diet was formulated on the basis of the digestible nutrients of RSM. Heat-treated RSM, with protein of low rumen degradability, is of poor value in pig feeding due to the low digestibility and availability of its protein.