• An investigation of anticoccidial veterinary drugs as emerging organic contaminants in groundwater

      Mooney, D.; Richards, Karl G.; Danaher, Martin; Grant, Jim; Gill, L.; Mellander, Per-Erik; Coxon, C.E.; Teagasc Walsh Scolarship Programme; Science Foundation Ireland; European Union; et al. (Elsevier BV, 2020-12)
      Intensification of the food production system to meet increased global demand for food has led to veterinary pharmaceuticals becoming a critical component in animal husbandry. Anticoccidials are a group of veterinary products used to control coccidiosis in food-producing animals, with primary prophylactic use in poultry production. Excretion in manure and subsequent land-spreading provides a potential pathway to groundwater. Information on the fate and occurrence of these compounds in groundwater is scant, therefore these substances are potential emerging organic contaminants of concern. A study was carried out to investigate the occurrence of anticoccidial compounds in groundwater throughout the Republic of Ireland. Twenty-six anticoccidials (6 ionophores and 20 synthetic anticoccidials) were analysed at 109 sites (63 boreholes and 46 springs) during November and December 2018. Sites were categorised and selected based on the following source and pathway factors: (a) the presence/absence of poultry activity (b) predominant aquifer category and (c) predominant groundwater vulnerability, within the zone of contribution (ZOC) for each site. Seven anticoccidials, including four ionophores (lasalocid, monensin, narasin and salinomycin) and three synthetic anticoccidials (amprolium, diclazuril and nicarbazin), were detected at 24% of sites at concentrations ranging from 1 to 386 ng L−1. Monensin and amprolium were the two most frequently detected compounds, detected at 15% and 7% of sites, respectively. Multivariate statistical analysis has shown that source factors are the most significant drivers of the occurrence of anticoccidials, with no definitive relationships between occurrence and pathway factors. The study found that the detection of anticoccidial compounds is 6.5 times more likely when poultry activity is present within the ZOC of a sampling point, compared to the absence of poultry activity. This work presents the first detections of these contaminants in Irish groundwater and it contributes to broadening our understanding of the environmental occurrence and fate of anticoccidial veterinary products.
    • Survival characteristics of monophasic Salmonella Typhimurium 4,[5],12:i:- strains derived from pig feed ingredients and compound feed

      Burns, Ann Marie; Duffy, Geraldine; Walsh, Des; Tiwari, Brijesh K; Grant, Jim; Lawlor, Peadar G; Gardiner, Gillian E.; Teagasc Walsh Fellowship Programme; 2011010 (Elsevier, 2015-12-09)
      The presence of Salmonella in animal feed or feed ingredients at the feed mill or on-farm is a cause for concern, as it can be transmitted to food-producing animals and subsequently to humans. The objective of this study was to determine the survival characteristics of five feed ingredient- and feed-derived monophasic Salmonella Typhimurium 4,[5],12:i:- strains. The first part of the study investigated thermal inactivation using an immersed heating coil apparatus. A Weibull model provided a good fit, with low RMSE values (0.04–0.43) and high R2 values (0.93–0.99) obtained. There was considerable inter-strain variation in heat resistance, with D-values ranging from 397.83 to 689 s at 55 °C, 11.35–260.95 s at 60 °C and 1.12 to 6.81 at 65 °C. Likewise, z-values ranged from 2.95 to 5.44 °C. One strain demonstrated a significantly higher thermal tolerance, even though it had been isolated from a meal feed. However, overall the strains investigated do not appear to be that much more heat resistant than Salmonella previously studied. The second part of this study involved assessing the ability of the five Salmonella strains to survive during storage over a 28-day period in pelleted weaner pig feed treated with 0.3% sodium butyrate. While a mean reduction in the Salmonella count of 0.79 log10 CFU was seen in the treated feed during the storage period, a reduction (albeit only 0.49 log10 CFU) was also observed in the control feed. Although there was no overall effect of treatment, sodium butyrate resulted in reductions in Salmonella counts of 0.75 and 0.22 log10 CFU at days 14 and 24 of feed storage, respectively but at the end of the 28-day storage period counts were 0.25 log10 CFU higher in the treated feed. Therefore, the sodium butyrate used appears unsuitable as an agent for feed treatment perhaps due to the protective coating on the particular feed additive used. Overall, the results of this study enhance knowledge about the behaviour and survival characteristics of monophasic S. Typhimurium 4,[5],12:i:- strains in animal feed and may assist the feed industry and pig producers in implementing effective intervention strategies for their control.