BEHAVIOURAL ANALYSIS OF PIGS WHEN PRESENTED WITH PEA-DIETS
The high dietary energy and acceptable digestible lysine content of field peas in comparison to soybean meal should allow for their incorporation into a wide range of diets. However, in part because of concerns over palatability, usage is limited in diets for swine. The objectives of this study were 1) to determine if peas reduce feed intake and if the pattern of consumption is indicative of a taste effect or post-ingestive feedback 2) to determine whether post-ingestive feedback plays a role in pigs’ aversion to peas and 3) to determine the effect of peas on the feeding behavior of pigs. Experiment 1 examined the effect of level of pea inclusion on feed consumption. Fifty mixed gender pigs (9 weeks old) were fed 5 treatment diets (basal soy diet, 20, 40, 60% peas, canola control) in a completely randomized design for 10 days. The peas were added at the expense of wheat and soy to the basal soy diet. The canola diet was required to evaluate the response to a novel diet. No dietary effects were seen as consumption levels were not different for either 20, 40 or 60% pea diets, compared to the soy basal or canola control diets (P = 0.16). Experiment 2 was designed to examine post-ingestive feedback effects of peas. Twenty mixed gender pigs (8 weeks old) were fed either a 60% pea or a 10% canola diet on alternate days for 10 days. The diets were flavored with 6 gm/kg of either orange or grape Kool-AidTM, with 10 pigs receiving peas/grape and canola/orange, and 10 receiving peas/orange and canola/grape on alternate days. Pigs were then presented with both an orange flavored and grape flavored basal diet to assess flavor preferences. The assumption is that if a diet produced negative post-ingestive feedback it would reduce feed consumption of the associated flavor during preference testing. Pigs did not exhibit a preference for either grape over orange flavor (P = 0.46). This was irrespective of which diet had previously been associated with grape flavoring, as evidenced by the similarity in feed intake between the two diets (0.88 ± 0.3 and 0.89 ± 0.2 kg for pea and canola-based diets, respectively; mean ± SD, P = 0.94). Experiment 3 was conducted to study the short term feeding behavior of grower pigs when presented with novel pea diets. Five dietary treatments which included peas from two sources and two grinds and a control soy meal diet were used. The results of the analysis of the eating behavior showed differences in the number of meals, average meal duration and average eating time per meal (P < 0.01) between pea diets and soybean meal diet. The pigs fed pea diets had shorter meals than the ones on control (12.2 vs 14.7 ± 1.04 minutes) but the meals were more frequent (12.6 vs 9.3 ± 1.25). The presence of peas affected feeding behavior but it was transitory. Moreover, the change in behavior did not affect the feed intake of the pigs. The above experiments indicate that it is possible to include high levels of peas in pig diets without affecting feed intake. In conclusion, peas used in this study did not have any palatability issues suggesting that pea inclusion in diets does not affect feed intake.
Palatability, Taste, Post-ingestive feedback, Feeding behaviour
Master of Science (M.Sc.)
Animal and Poultry Science