Growth and health of piglets fed colour flowered faba bean in relation to tannin content

Abstract: There is an increasing need and interest to use domestic protein feed ingredients in Swedish pig diets instead of imported soybean, particularly in organic production. Due to its tannin content, colour flowered faba bean has been disregarded in this sense, yet it yields more and is grown more in Sweden than the white flowered which is void of tannins. From the literature review it appears that tannin slightly reduces the nutritional value of colour flowered faba bean, particularly protein, but is not toxic. With sensible diet optimization using standardized ileal digestibility values and net energy, colour flowered faba bean could be successfully included in pig diets. Thus, to test its use under Swedish circumstances with emphasis on organic conditions, a feeding experiment was conducted to elucidate the effects on pig growth and health. In a randomized block design, 360 newly weaned piglets divided on six batches were fed colour or white flowered faba bean at 10 or 20% inclusion, or a control diet with soybean expeller. The diets were made to simulate organic diets. No differences were found between the treatments, indicating colour flowered faba bean can be used as well as white flowered and soybean. However, during the experiment confounding effects came into play: oedema disease and mouldy feed. Thus, there was a large variation in data, possibly masking treatment effects. Results from a previous part of the same study, testing conventional feeds, found that the faba bean diets had a better feed conversion ratio and higher daily weight gain than the soybean control. In conclusion, colour flowered faba bean has good potential in well balanced diets in Swedish pig production.