In the context of disease pathogenesis, it has been observed that after inadequate administration of antibiotics, animals become more susceptible to intestinal colonization and organ invasion by enteropathogens, these could be related to changes caused in the gastrointestinal microbial community. Therefore, we must reconsider the negative consequences that disruption of the microbiome has in the biology of metazoans (dysbacteriosis). Alternations of the intestinal microbiota composition in animals can be caused by multiple factors, including the misuse of antibiotics, having as a result a negative impact on the development and function of the immune, endocrine, nervous, and digestive systems. For this reason, social concerns regarding the development of antibiotic-resistant microorganisms have resulted in an urgent necessity to find feasible alternatives to maintain animal health and performance without the use of antibiotic growth promoters (AGP), in order to sustain livestock production as an economically viable source of food for human consumption. Hence, research about AGP alternatives such as probiotics, prebiotics, phytochemicals, organic acids, enzymes, and vaccines has become a priority for many scientists around the world.

Good animal health is of great importance for the efficient production of animal-derived foods at a low cost. The demand for solutions for animal health maintenance and disease prevention is a major global challenge in animal production, food safety, and public health. The animal body has a complete self-defense system, including oxidation and anti-oxidation balance, immune activation and suppression balance, pro- and anti-inflammatory balance, which can help the host against various factors that endanger normal life activities. Nowadays, the strategy of nutrition-based health has become an increasingly important solution for animal health maintenance and disease prevention. Nutrients (carbohydrates, fats, proteins, minerals, vitamins, et al.) and nutricines (carotenoids, enzymes, fatty acids, flavors, oligosaccharides, organic acids, phospholipids, polyphenols, et al.) are two major categories of components in feeds. Nutricines and some derivatives of nutrients (vitamin derivatives, amino acid derivatives, et al.) have been intensively studied in animal and cell culture models, and their roles in animal health maintenance and disease prevention are intimately known.

This unique work compiles the latest knowledge around veterinary nutraceuticals, commonly referred to as dietary supplements, from ingredients to final products in a single source. More than sixty chapters organized in seven sections collate all related aspects of nutraceutical research in animal health and disease, among them many novel topics: common nutraceutical ingredients (Section-I), prebiotics, probiotics, synbiotics, enzymes and antibacterial alternatives (Section-II), applications of nutraceuticals in prevention and treatment of various diseases such as arthritis, periodontitis, diabetes, cognitive dysfunctions, mastitis, wounds, immune disorders, and cancer (Section-III), utilization of nutraceuticals in specific animal species (Section-IV), safety and toxicity evaluation of nutraceuticals and functional foods (Section-V), recent trends in nutraceutical research and product development (Section-VI), as well as regulatory aspects for nutraceuticals (Section-VII). The future of nutraceuticals and functional foods in veterinary medicine seems bright, as novel nutraceuticals will emerge and new uses of old agents will be discovered. International contributors to this book cover a variety of specialties in veterinary medicine, pharmacology, pharmacognosy, toxicology, chemistry, medicinal chemistry, biochemistry, physiology, nutrition, drug development, regulatory frameworks, and the nutraceutical industry. This is a highly informative and carefully presented book, providing scientific insight for academia, veterinarians, governmental and regulatory agencies with an interest in animal nutrition, complementary veterinary medicine, nutraceutical product development and research.

In January of 2015, under the 1st International Caparica Conference in Antibiotic Resistance, a Research Topic entitled: “Surveying Antimicrobial Resistance: Approaches, Issues, and Challenges to overcome”, was published (http://journal.frontiersin.org/researchtopic/3763/surveying-antimicrobial-resistanceapproaches- issues-and-challenges-to-overcome). The problem of antimicrobial resistance (AMR), caused by excessive and inappropriate use of antibiotics, is a public health issue that concerns us all. The introduction of penicillin in the 1940s, the start of the antibiotics era, has been recognized as one of the greatest advances in therapeutic medicine. However, according to the World Health Organization (WHO), AMR infections are now an increasing worldwide public health threat and a post-antibiotic era is imminent, where common infections and minor injuries could be fatal. AMR is a typical ‘One Health’ problem, in which livestock animals and the environment constitute AMR reservoirs and transmission routes to and from the human population. Without effective antimicrobials to counter and prevent infections, other major achievements in modern medicine, such as organ transplantation, cancer chemotherapy and major surgery, risk being compromised. AMR infections in animals have negative outcomes on animal health, welfare, biosecurity and production. In 2006, the ban of growth promoting antibiotics highlighted antibiotic use in animal production as a risk factor in the development of antibiotic resistant bacteria. Bacteria can be transferred to humans via several routes; consumption of animal products, exposure through contact with animals, and the contamination of ground and surface waters by animal waste products. Therefore, it is of utmost importance that antimicrobial use in animals is reduced to a minimum, without compromising animal health and welfare. Mechanisms of bacterial antibiotic resistance are classified according to the types of antibiotic molecules or their targets in the cell. Environmental antibiotic-resistance genes are spread then acquired by clinically relevant microorganisms. Many resistance genes are conveyed into pathogen genomes via mobile genetic elements such as plasmids, transposons or integrons, increasing the propagation of potential resistant pathogens. Substantial progress has already been made in elucidating the basic regulatory networks that endow bacteria with their extraordinary capacity to adapt to a diversity of lifestyles and external stress factors. So how will we face bacteria in the future?