The digestibility of different oilseed protein sources and the effects of increasing canola meal (CM) in rations of growing pigs was studied by a team of Chinese researchers. In first experiment, four pigs weighing about 15.5 kg were fitted with simple T-cannula at terminal ileum and were fed four diets following repeated 4 × 4 Latin square design after having an adoption period of 7 days. Diet 1 was nitrogen-free diet containing corn starch. Diets 2, 3, and 4 were the basal diet supplemented with soybean meal (SBM), rapeseed meal (RSM), and domestic canola (CM). The composition of the oilseed protein meals tested is found in Table 1. SBM has higher levels of crude protein, indispensable and dispensable amino acids and lower amounts of crude fiber compared to RSM and CM.

The apparent ileal digestibility (AID) of crude protein and amino dietary indispensable acids of the experimental diets are presented in Table 2. Few of the amino acids and crude protein has shown significant responses (P ‹ 0.05) in the AID for the three protein ingredients. The AID of crude protein was lower in RSM but does not differ in CM in comparison to SBM Amino acid digestibility values were lower in diets supplemented with RSM for lysine, methionine, phenylalanine, alanine, aspartic acid, and proline compared to SBM.

Table 1. Proximate and amino acid composition of the protein sources used for ileal digestibility

Table 2. Standardized ileal digestibility of protein sources in pigs (*)

The standardized ileal digestibility (SID) of amino acids for the experimental diets containing the three different protein sources is presented in Table 3. The SID of dietary indispensable amino acids did not differ in the dietary treatments, but the SID of some of the dietary dispensable amino acids varied between protein supplements.

In second experiment, 192 growing pigs weighing about 25 kg were randomly allotted to four dietary treatments with increasing levels of CM (0, 3.75, 7.50, and 11.25 %). Diets were fed in meal form for 35 days. The experimental rations and pig performance are shown in Table 4.

Table 3. Standardized ileal digestibility of protein sources in pigs

Table 4. Effects of supplementation of canola meal on growth performance in growing pigs

In this experiment, increasing CM levels in growing pig diets had no effect on growth performance and apparent total tract digestibility of nutrients and energy P › 0.05). Total weight gain, total feed intake, and feed per unit of gain were not affected by increasing levels of CM in diets. (Editor’s note- Again, the choice of feed ingredient is based on availability, composition and price.)