María Aránzazu Martínez

Bio: María Aránzazu Martínez is an academic researcher from Complutense University of Madrid. The author has contributed to research in topics: Oxidative stress & European union. The author has an hindex of 15, co-authored 34 publications receiving 957 citations.

Fipronil insecticide toxicology: oxidative stress and metabolism

Abstract: Fipronil (FIP) is widely used across the world as a broad-spectrum phenylpyrazole insecticide and veterinary drug. FIP was the insecticide to act by targeting the γ-aminobutyric acid (GABA) receptor and has favorable selective toxicity towards insects rather than mammals. However, because of accidental exposure, incorrect use of FIP or widespread FIP use leading to the contamination of water and soil, there is increasing evidence that FIP could cause a variety of toxic effects on animals and humans, such as neurotoxic, hepatotoxic, nephrotoxic, reproductive, and cytotoxic effects on vertebrate and invertebrates. In the last decade, oxidative stress has been suggested to be involved in the various toxicities induced by FIP. To date, few reviews have addressed the toxicity of FIP in relation to oxidative stress. The focus of this article is primarily intended to summarize the progress in research associated with oxidative stress as a possible mechanism for FIP-induced toxicity as well as metabolism. The present review reports that studies have been conducted to reveal the generation of reactive oxygen species (ROS) and oxidative stress as a result of FIP treatment and have correlated them with various types of toxicity. Furthermore, the metabolism of FIP was also reviewed, and during this process, various CYP450 enzymes were involved and oxidative stress might occur. The roles of various compounds in protecting against FIP-induced toxicity based on their anti-oxidative effects were also summarized to further understand the role of oxidative stress in FIP-induced toxicity.

Plasma and tissue depletion of florfenicol and florfenicol-amine in chickens.

Abstract: Chickens were used to investigate plasma disposition of florfenicol after single intravenous (i.v.) and oral dose (20 mg kg-1 body weight) and to study residue depletion of florfenicol and its major metabolite florfenicol-amine after multiple oral doses (40 mg kg-1 body weight, daily for 3 days). Plasma and tissue samples were analyzed using a high-performance liquid chromatography (HPLC) method. After i.v. and oral administration, plasma concentration-time curves were best described by a two-compartment open model. The mean [ +/- standard deviation (SD)] elimination half-life (t1/2beta) of florfenicol in plasma was 7.90 +/- 0.48 and 8.34 +/- 0.64 h after i.v. and oral administration, respectively. The maximum plasma concentration was 10.23 +/- 1.67 microg mL-1, and the interval from oral administration until maximal concentration was 0.63 +/- 0.07 h. Oral bioavailability was found to be 87 +/- 16%. Florfenicol was converted to florfenicol-amine. After multiple oral dose (40 mg kg-1 body weight, daily for 3 days), in kidney and liver, concentrations of florfenicol (119.34 +/- 31.81 and 817.34 +/- 91.65 microg kg-1, respectively) and florfenicol-amine (60.67 +/- 13.05 and 48.50 +/- 13.07 microg kg-1, respectively) persisted for 7 days. The prolonged presence of residues of florfenicol and florfenicol-amine in edible tissues can play an important role in human food safety, because the compounds could give rise to a possible health risk. A withdrawal time of 6 days was necessary to ensure that the residues of florfenicol were less than the maximal residue limits or tolerance established by the European Union.

Fumonisins: oxidative stress-mediated toxicity and metabolism in vivo and in vitro

Abstract: Fumonisins (FBs) are widespread Fusarium toxins commonly found as corn contaminants. FBs could cause a variety of diseases in animals and humans, such as hepatotoxic, nephrotoxic, hepatocarcinogenic and cytotoxic effects in mammals. To date, almost no review has addressed the toxicity of FBs in relation to oxidative stress and their metabolism. The focus of this article is primarily intended to summarize the progress in research associated with oxidative stress as a plausible mechanism for FB-induced toxicity as well as the metabolism. The present review showed that studies have been carried out over the last three decades to elucidate the production of reactive oxygen species (ROS) and oxidative stress as a result of FBs treatment and have correlated them with various types of FBs toxicity, indicating that oxidative stress plays critical roles in the toxicity of FBs. The major metabolic pathways of FBs are hydrolysis, acylation and transamination. Ceramide synthase, carboxylesterase FumD and aminotransferase FumI could degrade FB1 and FB2. The cecal microbiota of pigs and alkaline processing such as nixtamalization can also transform FB1 into metabolites. Most of the metabolites of FB1 were less toxic than FB1, except its partial (pHFB1) metabolites. Further understanding of the role of oxidative stress in FB-induced toxicity will throw new light on the use of antioxidants, scavengers of ROS, as well as on the blind spots of metabolism and the metabolizing enzymes of FBs. The present review might contribute to reveal the toxicity of FBs and help to protect against their oxidative damage.

Effects of Probiotics, Prebiotics, and Synbiotics on Human Health.

Abstract: The human gastrointestinal tract is colonised by a complex ecosystem of microorganisms. Intestinal bacteria are not only commensal, but they also undergo a synbiotic co-evolution along with their host. Beneficial intestinal bacteria have numerous and important functions, e.g., they produce various nutrients for their host, prevent infections caused by intestinal pathogens, and modulate a normal immunological response. Therefore, modification of the intestinal microbiota in order to achieve, restore, and maintain favourable balance in the ecosystem, and the activity of microorganisms present in the gastrointestinal tract is necessary for the improved health condition of the host. The introduction of probiotics, prebiotics, or synbiotics into human diet is favourable for the intestinal microbiota. They may be consumed in the form of raw vegetables and fruit, fermented pickles, or dairy products. Another source may be pharmaceutical formulas and functional food. This paper provides a review of available information and summarises the current knowledge on the effects of probiotics, prebiotics, and synbiotics on human health. The mechanism of beneficial action of those substances is discussed, and verified study results proving their efficacy in human nutrition are presented.

Antibiotic alternatives: the substitution of antibiotics in animal husbandry?

Abstract: It is a common practice for decades to use of sub-therapeutic dose of antibiotics in food-animal feeds to prevent animals from diseases and to improve production performance in modern animal husbandry. In the meantime, concerns over the increasing emergence of antibiotic-resistant bacteria due to the unreasonable use of antibiotics and an appearance of less novelty antibiotics have prompted efforts to develop so-called alternatives to antibiotics. Whether or not the alternatives could relly replace antibiotics remains a controversial issue. This review summarizes recent development and perspectives of alternatives to antibiotics. The mechanism of actions, applications, and prospectives of the alternatives such as immunity modulating agents, bacteriophages and their lysins, antimicrobial peptides, pro-, pre- and synbiotics, plant extracts, inhibitors targeting pathogenicity (bacterial quorum sensing, biofilm and virulence), and feeding enzymes are thoroughly discussed. Lastly, the feasibility of alternatives to antibiotics is deeply analyzed. It is hard to conclude that the alternatives might substitute antibiotics in veterinary medicine in the foreseeable future. At the present time, prudent use of antibiotics and the establishment of scientific monitoring systems are the best and fastest way to limit the adverse effects of the abuse of antibiotics and to ensure the safety of animal-derived food and environment.

Introduction of a Qualified Presumption of Safety (QPS) approach for assessment of selected microorganisms referred to EFSA 1 Opinion of the Scientific Committee

Abstract: SUMMARY A wide variety of microbial species are used in food and feed production. Some have a long history of apparent safe use, while others are less well understood and their use may represent a risk for consumers. Experience has shown that there is a need for a tool for setting priorities within the risk assessment of those microorganisms used in food/feed production referred to EFSA and consequently the subject of a formal assessment of safety. To meet this need a system was proposed for a pre-market safety assessment of selected groups of microorganisms leading to a “Qualified Presumption of Safety (QPS)”. In essence this proposed that a safety assessment of a defined taxonomic group (e.g. genus or group of related species) could be made based on four pillars (establishing identity, body of knowledge, possible pathogenicity and end use). If the taxonomic group did not raise safety concerns or, if safety concerns existed, but could be defined and excluded (the qualification) the grouping could be granted QPS status. Thereafter, any strain of microorganism the identity of which could be unambiguously established and assigned to a QPS group would be freed from the need for further safety assessment other than satisfying any qualifications specified. Microorganisms not considered suitable for QPS would remain subject to a full safety assessment. EFSA asked its Scientific Committee to consider whether this system could be used to harmonise approaches to the safety assessment of microorganisms across the various EFSA scientific panels. If so, the Committee was requested to develop a strategy for the introduction of an assessment system based on the QPS concept.

The role of probiotics, prebiotics and synbiotics in animal nutrition

Abstract: Along with the intensive development of methods of livestock breeding, breeders' expectations are growing concerning feed additives that would guarantee such results as accelerating growth rate, protection of health from pathogenic infections and improvement of other production parameters such as: absorption of feed and quality of meat, milk, eggs. The main reason for their application would be a strive to achieve some beneficial effects comparable to those of antibiotic-based growth stimulators, banned on 01 January 2006. High hopes are being associated with the use of probiotics, prebiotics and synbiotics. Used mainly for maintenance of the equilibrium of the intestinal microbiota of livestock, they turn out to be an effective method in fight against pathogens posing a threat for both animals and consumers. This paper discusses definitions of probiotics, prebiotics and synbiotics. Criteria that have to be met by those kinds of formulas are also presented. The paper offers a list of the most commonly used probiotics and prebiotics and some examples of their combinations in synbiotic formulas used in animal feeding. Examples of available study results on the effect of probiotics, prebiotics and synbiotics on animal health are also summarised.