Grasslands: A Source of Secondary Metabolites for Livestock Health

Abstract

The need for environmentally friendly practices in animal husbandry, in conjunction with the reduction of the use of synthetic chemicals, leads us to reconsider our agricultural production systems. In that context, grassland secondary metabolites (GSMs) could offer an alternative way to support to livestock health. In fact, grasslands, especially those with high dicotyledonous plant species, present a large, pharmacologically active reservoir of secondary metabolites (e.g., phenolic compounds, alkaloids, saponins, terpenoids, carotenoids, and quinones). These molecules have activities that could improve or deteriorate health and production. This Review presents the main families of GSMs and uses examples to describe their known impact on animal health in husbandry. Techniques involved for their study are also described. A particular focus is put on anti-oxidant activities of GSMs. In fact, numerous husbandry pathologies, such as inflammation, are linked to oxidative stress and can be managed by a diet rich in anti-oxidants. The different approaches and techniques used to evaluate grassland quality for livestock health highlight the lack of efficient and reliable technics to study the activities of this complex phytococktail. Better knowledge and management of this animal health resource constitute a new multidisciplinary research field and a challenge to maintain and valorize grasslands.

Can alternative forages substantially reduce N leaching? findings from a review and associated modelling

“…For example, some forages produce PSM as a natural defence (photodamage, pathogens and herbivores) or an attractant (pollinators) to improve survival. Plant secondary metabolites are classified according to their chemical structure, composition and synthesis pathway and fall into one of three groups: terpenoids, alkaloids and phenolics (Poutaraud et al 2017;Villalba et al 2017) whose properties are discussed in the following section.…”

“…The second PSM are alkaloids which are a group of PSM containing nitrogen, being biosynthesised from amino acids, and are structurally very diverse (Poutaraud et al 2017). Bacteria, fungi, plants and even animals produce alkaloids, but in agriculture perhaps the most common alkaloids are those produced by endophyte fungi which have formed symbiotic associations with pasture species such as Lolium perenne and Festuca spp.…”

Nutritional Value, Mineral Composition, Secondary Metabolites, and Antioxidant Activity of Some Wild Geophyte Sedges and Grasses

“…The major antinutrients are alkaloids, flavonoids, saponins, tannins, oxalates, cyanogenic glycosides, phytic acid, gossypol, goitrogens, lectins, chlorogenic acid, protease and amylase inhibitors. The content of antinutritional factors in the plant depends on secondary metabolites, which vary with plant species, phenological periods, and environmental conditions [37]. Excess content of saponins in the fodder adversely affects animals, causing a depression of growth rates, inhibiting enzyme activity, and leading to a reduction in nutrient absorption in the digestive tract, as well as that saponins are bitter-tasting molecules [38].…”

The Combined Effect of Mediterranean Shrubland Pasture and the Dietary Administration of Sage By-Products on the Antioxidant Status of Segureña Ewes and Lambs

“…It is known that the beneficial effects of plant secondary metabolites, especially polyphenolic components, on livestock are associated with their antioxidant functions [ 22 ]. However, according to Poutaraud et al [ 23 ], there is no accurate information available concerning the dietary intake of polyphenols for herbivore husbandry. This fact explains the interest in assessing the major polyphenolic components synthesized by the plants normally grazed by sheep in Mediterranean shrublands during the autumn.…”