Preference for feed, but not growth performance, is reduced if hybrid rye replaces corn in diets for growing pigs

Two experiments were conducted to test the hypotheses that there is no difference in feed preference for diets containing hybrid rye or corn as the exclusive cereal grain source, and that hybrid rye may replace a portion of corn in diets for growing pigs without adversely affecting growth performance. In experiment 1, thirty-six pigs (initial body weight 32.0 ± 1.8 kg) were housed for 8 days in 18 pens with one gilt and one barrow in each pen. Each pen contained 2 identical feeders with one feeder containing a corn-based diet and the other feeder containing a diet based on hybrid rye. On each day, feed disappearance was calculated, feed allotment was recorded, and feeder positions were switched to minimize feeder preference. In experiment 2, one hundred and twenty eight growing pigs (initial body weight: 27.2 ± 2.2 kg) were allotted to 32 pens and 4 dietary treatments. A diet identical to the corn diet used in experiment 1 was used as the control diet, and 3 additional diets in which increasing proportions of corn were replaced with hybrid rye, were also formulated. Diets were fed for 27 days and body weights were determined at the start and at the end of the experiment. Results of experiment 1 demonstrated that preference ( %) for the hybrid rye-based diet was less (P < 0.05) than for the corn-based diet on each day and for the overall experiment. Results of experiment 2 indicated that there were no differences among treatments for initial or final body weight of pigs. Average daily gain (ADG) was not affected by dietary treatment, and the same was true for gain:feed (G:F). There was a tendency (linear, P < 0.10) for average daily feed intake to be reduced as hybrid rye inclusion in the diet increased. The reluctance of pigs to consume hybrid rye in the first experiment may be due to simple taste preference, but the satiating effects of the dietary fiber in hybrid rye in the gastrointestinal tract may also have contributed to the reduced feed intake observed in the second experiment. Nevertheless, ADG and G:F were unchanged by hybrid rye substitution for corn, indicating that growing pigs may be fed diets with high inclusion rates of hybrid rye without negatively impacting growth.