Nutritional value
Rapeseed meal is high in protein, fiber, vitamins, minerals, and bioactive compounds. It contains about 40% protein and a balanced amino acid composition.
In dairy cows, replacing soybean meal with rapeseed meal, maintained intake (with 20% rapeseed meal). Rapeseed meal is a suitable protein source for growing and finishing cattle. It is an excellent protein supplement for lactating dairy cows and can be included in relatively large amounts to their diet. Rapeseed meal has a good amino acid profile for ruminants, and contributes a significant amount of methionine, which is often the first limiting amino acid in production. In addition, the amino acid profile of the RUP fraction more closely matches requirements for maintenance and milk than other vegetable proteins. It is a good source of energy for ruminants. For solvent-extracted rapeseed meal, the net energy values for lactation cited in feed tables range from 6.8 to 7.45 MJ/kg DM. Digestibility is about 74-77%. Rapeseed meal is a highly palatable source of protein for ruminant animals.
Dosage
This protein is poorer in lysine than soybean (5.5% vs. 6.3% of the crude protein) but is richer in sulphur-containing amino acids (sum of methionine + cysteine: 4.3% vs. 3% of the crude protein). Rapeseeds are small and contain about 18-21% hulls, and the oil meal contains about 30% hulls. Thus rapeseed meal has a relatively high fibre content, crude fibre being between 10-18% of DM, which is higher than the crude fibre content of all types of soybean meals, but lower than that of other oil meals such as sunflower meal. Its lignin content is also high (about 10% of DM), whereas the lignin content of soybean meal is usually lower than 1%. The low lysine and high fibre content tends to limit the use of rapeseed meal in monogastric and fish species. Feeding pigs and poultry with rapeseed meal as their only source of supplementary protein often results in lower animal performance.
