The effects of antinutritional factors in legume seed and rapeseed on ruminant nutrition

Legume seeds and rapeseed meal provide an excellent potential source of pro tein supplement for the diet of ruminant animals. Unfortunately most legume seeds contain at least one antinutritional factor (ANF) such as alkaloids, lectins, tannins, and trypsin inhibitors. Because of detoxification in the rumen the negative effects of most ANF are less severe in ruminants than i n non ruminants. Tannins at low levels may even show positive responses. Ot her legume seeds such as peanuts (Arachis hypogaea) and soya beans (Glycine max) can produce sever allergenic reactions in animals that are exposed to them. However, the literature indicates that only preruminant calves appea r to have problems from the development of antigens to soya protein. Extracted rapeseed (Brassica spp) meal from some cultivars can contain sign ificant levels of glucosinolates. These compounds, which are goitrogenic, a re apparently not destroyed in the rumen. Trials have shown that they can a ffect both thyroxine and trioodiothyronine levels in the blood. Further, hi stological effects of goitrogenicity on the thyroid glands of rapeseed fed ruminant animals have been observed. This paper reviews recent developments on the impact of these factors on th e nutrition of ruminant animals.