Effects of ammoniation of canola seed contaminated with wild mustard seed on growth, feed utilization and carcass characteristics of pigs

Ammoniation (NH 3 ) of canola seed (CS) containing wild mustard seed (WMS) present as a contaminant resulted in reduction of CS glucosinolates but not of WMS hydroxybenzyl glucosinolate or lysine contents. Feeding diets containing 25% CS including 0, 3, 6 and 9% WMS to crossbred barrows from 23 to 57 kg had no effects on average daily gain (ADG) or daily feed intake (FI) but feed:gain ratio (FG) was poorer. Serum triiodothyronine (T 3 ) was unaffected but thyroxine (T 4 ) was depressed by WMS, a result of hydroxybenzyl glucosinolate intake. FI was improved by NH 3 . This was attributed to reduced concentrations of sinapine and glucosinolates in CS and WMS. Barrows fed from 57 to 100 kg liveweight showed no effect of dietary level of WMS on ADG or FG but 7.2 and 10.8% WMS resulted in leaner carcasses than with 0% WMS. Use of 30% CS in the diet, regardless of WMS level, resulted in fatty acid changes in backfat compared with the control diets. Fatty acids C14, C16, C16:1 and C18 were reduced and C18:1, C18:2 and C18:3 were increased by consuming diets containing 10–12% oil from CS and WMS. Gilts (57–100 kg) fed diets containing 0.2 and 10.5% WMS in CS fed at 30% of the diet had similar ADG but gilts fed the high WMS diet produced leaner carcasses. Key words: Canola seed, wild mustard, pigs, feeding, glucosinolates, fatty acids