Salmonella enterica is the most important foodborne pathogen, and it is often associated with the contamination of poultry products. Annually, Salmonella causes around 93 million cases of gastroenteritis and 155,000 deaths worldwide. Antimicrobial therapy is the first choice of treatment for this bacterial infection; however, antimicrobial resistance has become a problem due to the misuse of antibiotics both in human medicine and animal production. It has been predicted that by 2050, antibiotic-resistant pathogens will cause around 10 million deaths worldwide, and the WHO has suggested the need to usher in the post-antibiotic era. The purpose of this review is to discuss and update the status of Salmonella antibiotic resistance, in particular, its prevalence, serotypes, and antibiotic resistance patterns in response to critical antimicrobials used in human medicine and the poultry industry. Based on our review, the median prevalence values of Salmonella in broiler chickens, raw chicken meat, and in eggs and egg-laying hens were 40.5% ( interquartile range [IQR] 11.5-58.2%), 30% (IQR 20-43.5%), and 40% (IQR 14.2-51.5%), respectively. The most common serotype was Salmonella Enteritidis, followed by Salmonella Typhimurium. The highest antibiotic resistance levels within the poultry production chain were found for nalidixic acid and ampicillin. These findings highlight the need for government entities, poultry researchers, and producers to find ways to reduce the impact of antibiotic use in poultry, focusing especially on active surveillance and finding alternatives to antibiotics.

Acute toxicity of the glyphosate -N (phosphonomethyl) glycine- herbicide, Roundup®, in juveniles of cachama blanca, (Piaractus brachypomus), was evaluated and the histopathological lesions were assessed. The 96 h lethal concentration 50 was 97.47mg.L-1 (P<0.05). In the gill, necrotic and proliferative lesions were detected. In the liver, congestion, degenerative foci, hyaline droplets and lipidic vacuolization of the hepatocytes were observed. In the stomach mild hyperplasia of mucous cells was detected, which was also observed in the skin. In this latter tissue, a large increase in the thickness of the epidermis with necrotic lesions, infiltration of leukocytes and melanin pigment were observed. In the brain, degenerative foci of neuronal bodies in the telencephalon associated with gliosis and infiltration of eosinophilic granule cells/mast cells were shown. In conclusion, gills, liver, skin and brain are susceptible to Roundup®. Moreover, effects on the central nervous system could affect olfaction as well as individual and group behavior, the reproductive performance of the fish and hence have repercussions at the population level.

RESUMENEl eugenol (aceite de clavo) es un compuesto que ha sido ampliamente utilizado como anestésico en peces debido a sus cortos tiempos de inducción y recuperación. El objetivo del estudio fue determinar la concentración anestésica efectiva del eugenol en 40 peces escalares (Pterophyllum scalare) bajo condiciones de laboratorio. Los animales fueron expuestos a cuatro concentraciones de la solución anestésica (20, 30, 40 y 50 mg/L de eugenol) y las observaciones se hicieron en los estadios de inducción a la anestesia (I, II, III) y recuperación (I, II, III, IV). Los animales expuestos a las mayores concentraciones de eugenol (40 y 50 mg/L) entraron rápidamente en inducción; sin embargo, fueron los que más tardaron en recuperarse (p<0.05). En una concentración de 20 mg/L se induce anestesia ligera en peces escalares (estadio I de anestesia), en tanto que una concentración de 50 mg/L se induce un estadio de anestesia avanzado (III). La concentración anestésica más efectiva fue de 40 mg/L de eugenol para alevinos de peces escalares.Palabras clave: peces ornamentales, anestesia, eugenol, escalares ABSTRACT Eugenol (clove oil) has been widely used as an anaesthetic in fishes due to low induction and recovery times. The aim of this study was to assess the anaesthetic concentration of eugenol in 40 angel fish (Pterophyllum scalare) under laboratory conditions. The animals were exposed to four concentrations of eugenol (20,30, 40 and 50 mg/L). Observations of the anaesthetics induction (phase I, II, and III) and recovery (phase I, II, III, and IV) were registered. The animals exposed to the higher concentrations of eugenol (40 and 50 mg/L) reached in a short time the first induction anaesthetic stage but had the longer recovery time (p<0.05). The 20 mg/L concentration of eugenol induce

In aquaculture and biological research, anaesthetics are widely used to minimize fish stress and injury during handling procedures such as sorting, morphometry measurements, blood sampling, tagging, transportation and vaccination, promoting the welfare of the fish (Wagner, Singer, & Mckinley, 2015). Some considerations such as efficacy, cost, availability and toxicity are important in order to choose the proper anaesthetic (Akbulut, Çakmak, Aksungur, & Çavdar, 2011). There are two types of commercial anaesthetics: natural and synthetic (Purbosari, Warsiki, Syamsu, & Santoso, 2019). Synthetic anaesthetic agents have been widely used in aquaculture including tricaine methanesulfonate (MS-222), quinaldine and 2-phenoxyethanol (Façanha & Gomes, 2005). However, they have some limitations given their high cost and associated toxicity (Velisek et al., 2006). Among natural agents, clove oil is the most common anaesthetic used in freshwater,