title: Effect of strategic administration of an encapsulated blend of formic acid, citric acid, and essential oils on Salmonella carriage, seroprevalence, and growth of finishing pigs.
abstract: Controlling Salmonella at farm level can act as the first line of defence in reducing salmonellosis from pork. This study investigated the efficacy of an encapsulated blend of formic acid, citric acid, and essential oils (FormaXOL™) administered to finisher pigs for 28days prior to slaughter in controlling Salmonella shedding on a commercial farm with a history of high Salmonella seroprevalence. Fourteen pens of 8-10 pigs/pen were randomly assigned to a control (finisher diet without additive) or a treatment group (the same diet with 4kg/t of FormaXOL™) for 28 days. Faeces were collected from each pig on days 0, 14, and 28, while on day 29 blood, caecal digesta and ileocaecal-mesenteric lymph nodes were collected at slaughter. Pigs were weighed at the start and end of the trial, feed intake was recorded, and carcass quality parameters were recorded at slaughter. On day 14, Salmonella shedding was reduced in the treatment compared to the control group (27.9% versus 51.7% probability of detecting Salmonella in faeces, respectively; p=0.001). However, on day 28, no reduction was observed (20.6% versus 35.9% probability of detecting Salmonella in faeces, respectively; p=0.07). Interestingly, Salmonella shedding rates in the treated pigs remained stable throughout the trial compared to the control group. This suggests that the feed additive prevented additional pigs from acquiring the Salmonella infection. A lower Salmonella seroprevalence was detected at slaughter in the treatment compared to the control group using the 40% optical density cut-off (64.5% versus 88.5%, respectively; p=0.01). However, no significant differences in Salmonella recovery rates were observed in the caecal digesta or lymph nodes between treated and control groups. Treated pigs had a lower feed intake than pigs fed the control diet (p=0.001); however, average daily gain and feed conversion efficiency were not affected by treatment (p=0.45 and 0.55, respectively). Consequently, supplementing the diet with FormaXOL™ for 28days increased the feed cost per kg of live-weight gain by €0.08. Overall, results suggest that strategic administration of an encapsulated blend of formic acid, citric acid, and essential oils, to finishing pigs for 28days prior to slaughter has potential to prevent increased Salmonella shedding at certain time points as well as seroprevalence. However, this additive did not lower intestinal carriage, nor did it reduce seroprevalence to below the cut-off used for the high Salmonella risk category in Ireland (50%) or improve growth performance.
authors.affiliation: Teagasc, Food Research Centre, Ashtown, Dublin 15, Ireland; Department of Science, Waterford Institute of Technology, Waterford, Ireland; Teagasc, Pig Development Department, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, Ireland.
authors.forename: Kavita
authors.initials: K
authors.lastname: Walia
authors.affiliation: Teagasc, Food Research Centre, Ashtown, Dublin 15, Ireland.
authors.forename: Hector
authors.initials: H
authors.lastname: Argüello
authors.affiliation: Teagasc, Food Research Centre, Ashtown, Dublin 15, Ireland; School of Veterinary Medicine, University College Dublin, Dublin, Ireland; Teagasc, Pig Development Department, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, Ireland.
authors.forename: Helen
authors.initials: H
authors.lastname: Lynch
authors.affiliation: School of Veterinary Medicine, University College Dublin, Dublin, Ireland.
authors.forename: Finola C
authors.initials: FC
authors.lastname: Leonard
authors.affiliation: Teagasc, Food Research Centre, Ashtown, Dublin 15, Ireland.
authors.forename: Jim
authors.initials: J
authors.lastname: Grant
authors.affiliation: Department of Agriculture, Food and the Marine, Central Veterinary Research Laboratory, Backweston, Ireland.
authors.forename: Dermot
authors.initials: D
authors.lastname: Yearsley
authors.affiliation: Department of Agriculture, Food and the Marine, Central Veterinary Research Laboratory, Backweston, Ireland.
authors.forename: Sinead
authors.initials: S
authors.lastname: Kelly
authors.affiliation: Teagasc, Food Research Centre, Ashtown, Dublin 15, Ireland.
authors.forename: Geraldine
authors.initials: G
authors.lastname: Duffy
authors.affiliation: Department of Science, Waterford Institute of Technology, Waterford, Ireland. Electronic address: ggardiner@wit.ie.
authors.forename: Gillian E
authors.initials: GE
authors.lastname: Gardiner
authors.affiliation: Teagasc, Pig Development Department, Animal and Grassland Research and Innovation Centre, Moorepark, Fermoy, Co. Cork, Ireland.
authors.forename: Peadar G
authors.initials: PG
authors.lastname: Lawlor
mesh_terms: D000818:Animals; D019343:Citric Acid / Q000008:administration & dosage / Q000627:therapeutic use*; D004338:Drug Combinations; D005260:Female; D005561:Formates / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D009822:Oils, Volatile / Q000008:administration & dosage / Q000627:therapeutic use*; D012481:Salmonella Infections, Animal / Q000188:drug therapy* / Q000453:epidemiology; D016036:Seroepidemiologic Studies; D013552:Swine / Q000382:microbiology; D013553:Swine Diseases / Q000188:drug therapy* / Q000453:epidemiology
chemical_list: D004338:Drug Combinations; D005561:Formates; D009822:Oils, Volatile; C030544:formic acid; D019343:Citric Acid
keywords: Cost; Dietary supplementation; Organic acid; Pig farm; Swine