Feed intake, growth and carcass parameters of swine consuming diets containing low levels of deoxynivalenol from naturally contaminated barley

Abstract

The ubiquitous nature of deoxynivalenol (DON) in the eastern prairie region of Canada necessitates the development of strategies to enhance the utilization of affected grains by swine producers. To this end, an experiment was designed to determined the impact of low levels of DON on feed intake and growth of swine. 144 Cotswold pigs (initial weight = 23.4 kg ± 0.3 SE) were assigned to receive diets containing either 0, 1 or 2 ppm DON in the final feed (four pens, each containing six barrows and six gilts, per treatment). The final DON contents of the diets were derived by diluting DON-contaminated barley (DON = 4.9 ppm) with DON-free barley. Diets were formulated to provide a minimum of 13.4 MJ kg-1 digestible energy (DE) and 0.81% total lysine, and the same diets were used throughout the grow-finish period. Feed intake (per pen basis; kg d-1), body weight gains (kg d-1) and feed conversion were measured on a weekly basis. Pigs were slaughtered at approximately 110 kg and indices of carcass merit collected. The presence of 2 ppm DON depressed feed intake by 7.6% (P < 0.05) relative to 0 ppm DON controls, with pigs consuming the 1 ppm DON diet having intermediate levels of feed depression. However there was no significant effect of DON on average daily gain or feed conversion at any stage of the experiment, The presence of DON in the diet increased the proportion of animals reaching 110 kg, estimated from individual regression curves, at times greater than the median value (169.5 d; chi-squared analysis P < 0.05), in gilts, but was without effect on barrows (median = 158.2 d). Measures of carcass weight, index, backfat thickness, and depth of lean over the loin were not affected (P > 0.05) by the presence of DON in the diet, irrespective of gender, however there was significant linear effect of DON (P < 0.05) on the loin premiums received, with higher values realized with increasing DON content in the diet. The current data provide evidence that grains containing DON could be used in the diets of barrows to provide 2 ppm in the final feed however, caution is required when considering their utilization for gilts. Key words: Deoxynivalenol, feed intake, performance, swine, barley, carcass merit