SOLVENT-EXTRACTED RAPESEED OIL MEAL AS A PROTEIN SOURCE FOR PIGS AND RATS: II. NITROGEN DIGESTIBILITY AND RETENTION; AND ENERGY AND DRY MATTER DIGESTIBILITY
Rats and pigs received diets containing solvent-extracted rapeseed oil meal (R.O.M.) substituted on an equivalent protein basis for 0 to 100 per cent of the dietary soybean oil meal (S.O.M.). R.O.M. represented up to 15.6 per cent of the total diet. Apparent nitrogen (N), energy and dry matter (D.M.) digestibility coefficients were reduced during growth (4 to 5 weeks of age) when rats received R.O.M. in replacement for 50 or 100 per cent of the dietary S.O.M., and during gestation when they received R.O.M. in replacement for 25 to 100 per cent of the S.O.M. Results with pigs were similar but less consistent. Retention of gross N or digested N was lower in rats receiving R.O.M. in substitution for over 50 per cent of the S.O.M. during growth or over 25 per cent of the S.O.M. during gestation. A supplement of 0.2 per cent L-lysine added to the diet containing the highest level of R.O.M. had no influence on digestibility or retention in rats but improved N, energy and D.M. digestibilities for pigs at 75 pounds liveweight and during gestation and lactation. Sex of rats did not influence digestibility coefficients, but boars were more efficient than gilts in digesting energy and D.M.