Tannins in Ruminant Nutrition: Impact on Animal Performance and Quality of Edible Products

Tannins are widespread throughout the plant kingdom, occurring as hydrolysable and condensed tannins and at different levels in several animal feeding sources. Recent years have seen an increasing interest in the use of tannin-rich plants and plant extracts in ruminant diets for improving the quality of their edible products. Some results show that this strategy is effective in improving the fatty acid profile of meat and milk, increasing the level of health-beneficial fatty acids as well as enhancing the oxidative stability of the products. However, the use of tannin-rich feed in animal diets requires great care, due to its possible detrimental effects on animal performance and induction of metabolic disorders. Although promising, the results of studies on the effects of tannins on animal performance and quality of their products are still controversial, probably depending on type and chemical structure of tannins, amount ingested, composition of diet, and species of animal. In this chapter, the current knowledge regarding the effect of dietary tannins on animal performance and the quality of their products (meat and milk), particularly on the fatty acid profile, oxidative stability, and organoleptic properties, is reviewed. The tannin chemistry diversity and its occurrence in ruminant diets, as well as its beneficial and adverse effects on ruminants, will be briefly reviewed, and aspects related to oral cavity physiology, saliva production/composition, and postingestive effects will also be discussed.

“Biomarkers in a One Health perspective: current knowledge of their ability to merge human and animal health

Biomarkers are nowadays essential tools to be one step ahead for fighting disease, enabling an enhanced focus on disease prevention and on the probability of its occurrence. Research in a multidisciplinary approach has been an important step towards the repeated discovery of new biomarkers. Biomarkers are defined as biochemical measurable indicators of the presence of disease or as indicators for monitoring disease progression. Currently, biomarkers have been used in several domains such as oncology, neurology, cardiovascular, inflammatory and respiratory disease, and several endocrinopathies. Bridging biomarkers in a One Health perspective has been proven useful in almost all of these domains. In oncology, humans and animals are found to be subject to the same environmental and genetic predisposing factors: examples include the existence of mutations in BR-CA1 gene predisposing to breast cancer, both in human and dogs, with increased prevalence in certain dog breeds and human ethnic groups. Also, breast feeding frequency and duration has been related to a decreased risk of breast cancer in women and bitches. When it comes to infectious diseases, this parallelism is prone to be even more important, for as much as 75% of all emerging diseases are believed to be zoonotic. Examples of successful use of biomarkers have been found in several zoonotic diseases such as Ebola, dengue, leptospirosis or West Nile virus infections. Acute Phase Proteins (APPs) have been used for quite some time as biomarkers of inflammatory conditions. These have been used in human health but also in the veterinary field such as in mastitis evaluation and PRRS (porcine respiratory and reproductive syndrome) diagnosis. Advantages rely on the fact that these biomarkers can be much easier to assess than other conventional disease diagnostic approaches (example: measured in easy to collect saliva samples). Another domain in which biomarkers have been essential is food safety: the possibility to measure exposure to chemical contaminants or other biohazards present in the food chain, which are sometimes analytical challenges due to their low bioavailability in body fluids, is nowadays a major breakthrough. Finally, biomarkers are considered the key to provide more personalized therapies, with more efficient outcomes and fewer side effects. This approach is expected to be the correct path to follow also in veterinary medicine, in the near future.