The potential of condensed tannin-rich feedstuff to affect the nutritional and sensory qualities of ruminant-based products

Over the last decade, interest has increased when it comes to using temperate forage legumes containing condensed tannins (CT) for ruminants. The reason for this is that CT have been shown to benefit animal health and performance, as CT reduce parasitic burden by gastrointestinal nematodes, prevent bloat and reduce urinary nitrogen losses. Less is known about their impact on the quality of ruminant-based products. This short review discusses various quality issues which could, based on the current knowledge on the mode of action of CT, be positively affected by forages that are rich in CT. The main focus is the fatty acid composition, as well as the sensory traits of the meat, milk and cheese. The results presented here show the potential for two tanniferous forage legumes to positively affect the deposition of polyunsaturated fatty acids (PUFA), especially the n-3 fatty acids in meat, milk and cheese, and to improve the organoleptic quality of these products. From the two plants tested (birdsfoot trefoil and sainfoin), it is evident the CT effect in the digestive tract depends on various factors like the CT level, the chemical composition of the CT and whether the CT in the plant are available in a soluble form or bound to proteins or carbohydrates of the plants.