Potential Use of Silver Nanoparticles as an Additive in Animal Feeding

Abstract

Among other uses, metallic silver and silver salts have currently been applied as antimicrobial agents in many aspects of medical industries, such as coating of catheters, dental resin composites and burn wounds, as well as in homeopathic medicine, with a minimal risk of toxicity in humans. However, their use in animal feeding as prebiotics have remain minimised, mostly because of the low cost antibiotics used as growth promoters in the second half of the XX Century. However, after the ban of this practice in the European Community, silver compounds appear as a potential alternative to other already in use, such as organic acids, oligosaccharides, plant extracts, etc. The major concerns about the safe use of an additive in animal feeding are its effective role as antimicrobial, acting selectively over potential pathogens but not over symbiotic microbial communities; a low toxic effect over the animal and its human consumer; and a low risk of environmental pollution. Metallic silver nanoparticles (up to 100 nm) allow for a higher antimicrobial effect than silver salts, are more resistant to deactivation by gastric acids and have a low absorption rate through the intestinal mucosa, thus minimising its potential risk of toxicity. Besides, it has been shown that the doses that promote animal physiological and productive effects are very low (20 to 40 ppm), especially compared to the 10 to 100-fold higher concentration used with other metallic compounds such as copper and zinc, thus precluding a harmful environmental effect. This chapter describes the reasons why silver nanoparticles could be applied to animal feeding, and provides with some available data in this regard. In any case, its registration as feed additive is a previous requisite before being applied in practical conditions.

Perturbation of cellular mechanistic system by silver nanoparticle toxicity: Cytotoxic, genotoxic and epigenetic potentials

“…Analysis of various species including various strains of rats, mice, piglets etc., showed variable results [61,146]. Ag NPs were found to be accumulated in various organs of mammals, such as lung, kidney, liver, spleen, brain, and heart [147].…”

Nanotechnology in agri-food production: an overview

“…The results of a study of the effect of silver nanoparticles used as an additive in diets for weanling pigs on the digestive microbiota and gut morphology, and in productive performances and silver retention in tissues, suggested that silver effect may be mediated through its antimicrobial properties, either by acting against certain bacterial groups or just reducing the microbial load of the small intestine 231. Silver nanoparticles could be applied to animal feeding232 and are also a potent antimicrobial agent for use in broiler chickens 233. Magnetic nanoparticles were found successful for the recovery of aflatoxin B1 and zearalenone from feed utilizing monoclonal antibodies against aflatoxin B1 and zearalenone 234…”

Influence of in ovo injection and subsequent provision of silver nanoparticles on growth performance, microbial profile, and immune status of broiler chickens

“…The feed conversion ratio for the broilers did not differ between the treatment groups, which is accordance with the findings in quail 8 and broiler chickens 27 provided with silver nanoparticles via the drinking water, but not with data from weanling pigs supplemented with silver nanoparticle powder in the diet. 7 These conflicting results suggest that poultry species are either less sensitive to silver nanoparticle treatment than pigs, or that silver nanoparticles in powdered form provided via the feed is submit your manuscript | www.dovepress.com…”

“…4 Recently, renewed research interest has been directed towards use of silver as an alternative antimicrobial agent. [5][6][7] Metallic silver compounds and their ions have long been known to have unique antibacterial properties. Silver has been used since time immemorial for the treatment of burns, wounds, and bacterial infections.…”

“…6 However, the development of several low-cost antibiotics and the toxicity associated with ionic silver have markedly decreased its use as an antimicrobial agent. 6,7 The advent of nanotechnology and its applications has enabled the chemical, physical, and optical properties of metals to be altered dramatically. 6 This technology has made it possible to engineer silver in the nanosize range (1-100 nm) with a large functional surface area and more atoms exposed on the surface of the nanoparticles.…”