Abstract
The objective was to test the hypothesis that particle size and origin influence the apparent ileal digestibility (AID) of starch and the standardized ileal digestibility (SID) of amino acids (AA) in field peas. Three sources of field peas were procured. One source was from the U.S. and 2 sources were from Canada. The U.S. source and 1 of the sources from Canada (i.e., Canada 1) were each divided into 2 batches and ground at 200 or 400 µm, whereas the other source from Canada (i.e., Canada 2) was only ground at 200 µm. Each source of field peas was included in one diet as the only source of AA. An N-free diet was used to determine the basal endogenous losses of crude protein (CP) and AA. Barrows (n = 6; initial body weight: 50.5 kg; SD = 3.7) that had a T-cannula installed in the distal ileum were randomly allotted to a 6 × 6 Latin square design with 6 diets and six 7-d periods. Ileal digesta from pigs were collected for 2 days after 5 days of adaptation. The statistical model included source as the fixed effect and animal and period as the random effects. Contrast statements were used to analyze effects of particle size, origin, and the interaction between particle size and origin. Results indicated that the AID of starch was increased by reducing the particle size of the U.S. source, but that was not the case for the Canada 1 source (interaction; P < 0.001; Table 1). No interactions were observed for the SID of CP or AA. The SID of CP and AA was not affected by particle size of field peas. The SID of CP and Trp was greater (P < 0.05) and the SID of His, Ile, and Thr tended to be greater in the Canada 2 source (P < 0.10) than in the U.S. source. In conclusion, a few differences in the SID of AA in field peas produced in the U.S. or Canada were observed, but there was no effect on SID of AA of reducing the particle size of field peas from 400 to 200 µm. However, the effect of particle size on the AID of starch was greater in field peas from the U.S. compared with field peas from Canada.
