Hybrid rye is grown in Europe, Canada, and the United States, and compared with conventional rye, it has increased yields and reduced risk of ergot contamination, making it an interesting ingredient in the feeding of pigs. However, there is limited information about the nutritional value of hybrid rye when fed to pigs. Therefore, the objective of the experiment was to determine the standardized ileal digestibility (SID) of crude protein and amino acids, as well as the apparent ileal digestibility (AID) of starch in hybrid rye compared with barley, wheat, and corn.

Seven diets were formulated for this experiment. Six diets contained 94% of a single grain as the sole source of starch and amino acids. The six grains tested in the experiment were three hybrids of rye (Bono, Daniello, and Brasetto) and one source of barley, wheat, and corn. The last diet was a nitrogen-free diet that was used to determine basal endogenous losses of crude protein and amino acids. The three hybrids of rye were sourced from the seed company KWS Lochow GmBH (Bergen, Germany) whereas barley, wheat and corn were sourced locally.

Seven ileal cannulated growing barrows with an initial body weight of 26 kg were allotted to a 7 × 7 Latin Square Design with seven periods and seven treatments.  In each period, diets were fed for seven days, with the first five days being an adaptation period to the diet, followed by two days of ileal digesta collection. The ileal digesta were analyzed for crude protein, amino acids, and starch to calculate digestibility values.

The SID of CP was significantly greater (P < 0.05) in barley, wheat, and corn than in the three hybrids of rye, and this was also true for the SID of lysine, methionine, threonine, and tryptophan (Table 2). The AID of starch was significantly greater (P < 0.05) in wheat and corn than in the three hybrids of rye and barley; however, the AID of starch was greater than 95% in all cereal grains. Despite the lower SID of crude protein and amino acids observed in hybrid rye compared with the other grains, the concentrations of standardized ileal digestible crude protein and amino acids were similar in hybrid rye and corn (Table 3). The reason for this observation is that hybrid rye contains more amino acids than corn, so when the concentration of each amino acid is multiplied by the digestibility value, corn and hybrid rye will provide the same quantities of digestible amino acids to the diet.

• Hybrid rye has reduced SID of crude protein and amino acids compared with barley, wheat, and corn.
• Hybrid rye provides the same quantities of digestible amino acids to a diet compared with corn.
• The AID of starch was greater than 95% for all cereal grains, but hybrid rye and barley had lower AID of starch than wheat and corn.
• Hybrid rye contains more dietary fiber and fructans than barley, wheat, and corn, which may impact the digestibility of other nutrients.
• Further research will be conducted to determine the digestibility of energy and fiber in hybrid rye when fed to pigs.

Table 1. Analyzed nutrient composition of three sources of hybrid rye, barley, wheat, and corn, as-fed basis

Table 2. Standardized ileal digestibility (%) of crude protein and amino acids and apparent ileal digestibility (%) of starch in 3 sources of hybrid rye, barley, wheat, and corn

^a-d Means within a row lacking a common superscript letter are different (P < 0.05).

Table 3. Concentrations (g/kg) of standardized ileal digestible crude protein and amino acids in 3 sources of hybrid rye, barley, wheat, and corn

^a-e Means within a row lacking a common superscript letter are different (P < 0.05).

This report is based on unpublished research by Molly McGhee and Hans H. Stein.