Effect of Knotweed in Diet on Physiological Changes in Pig

Knotweeds ( Reynoutria spp.) are plants producing useful secondary metabolites, including stilbenes (resveratrol and piceid have been studied more thoroughly) and emodin. Many studies have shown the positive effects of resveratrol on the health status of humans and animals. Resveratrol has been added into pigs’ diet as a pure extract, but it has never been supplemented into the fodder with knotweed biomass which contains other secondary metabolites, thus we would expect it would provide a more complex effect. The study objective is to discover whether the 2 weight percent addition of knotweed into pigs’ diet will have positive effects on their health. We compared two groups of Prestice Black-Pied pigs, the experimental group was fed by fodder with the knotweed rhizomes additive, the control group without knotweed additive. Investigated parameters were feed consumption, the composition of excrements, weight increment, muscle-to-fat ratio, fatty acid composition and blood haematology and biochemistry. The addition of knotweed stimulated a whole range of physiological changes. It positively stimulated weight growth and increased the back fat and proportion of muscle, but statistically significant only in gilts. On the other hand, the changes in fatty acid composition seemed to be unsatisfactory. It is the first study of the effects of knotweed on pigs’ development, and more detailed research is desirable.