Effect of fumonisins and Salmonella on digestive flora profiles assessed using a molecular tool (CE-SSCP).

Abstract

Fumon1s1ns (FB) are mycotox1ns frequently found 1n vegetal feedstuffs , especially m maize used for p1g feeding. Among fumonisins , FB1 was the better described toxin. It caused pulmonary and hepatic damages as well as immune response disorders in pigs that were recognised as especially sensitive to FB Intoxication. The FB1 immunosuppressor induced a higher susceptibility of p1gs to gut pathogens such as E coli. Effects on Salmonella have poorly been studied despite the frequent asymptomatic carnage m pigs and the presumptive role of nora equilibrium on prevention of Salmonella excret1on or re-excretion. To determme the innuence of Salmonella carriage, fumon1sins or both on digest1ve nora equilibrium , the use of a molecular technique CE-SSCP (Capillary-ElectrophoresiS Single Strand Conformation Polymorphism) appeared a good complement to the conventional bacteriological techniques. The obJeCtive was to assess the perturbation of nora assoc1ated with co-exposition 1n expenmental conditions m absence of clinical sign Forty eight piglets were clustered following a 2x2 "factorial scheme• in order to analyse on faecal nora, the effect of a feeding naturally contammated with FB (8.5 ppm of FB , and 2.8 ppm of FB2) associated w1th an asymtomatic carriage of Salmonella Typhimunum. The effect of FB and Salmonella has been investigated onto 10 week old piglets and during 9 weeks. Faeces of the p1gs were taken regularly Bacteriological numeration of total aerobic nora was conducted. DNA of each sample was extracted us1ng the QIAmp DNA Stool Minik1t. The extracted DNA were pooled, the PCR amplification of the rONA 16S V3 reg1on was earned out. Then the PCR products were analysed by CE-SSCP. Profiles were classified v1a dendrograms usmg the BioNumerics software and the Jaccard coefficient for similarity determination In th1s study, 5 10 4 CFU Salmonella per pig induced infections and asymptomatic carriages that didn't affect the faecal nora profiles Intoxication of the p1gs by the contam1nated feed has been confirmed by the increase of the sphmganme/sphingos1ne ratio The 8.5 ppm concentration of FB, did not mduce any effect on the ammal health mdicators , but 1t affected transiently the d1gesllve nora equilibnum. In case of co-mfect1on with FB and Salmonella , the nora profiles were rapidly and strongly modified as soon as 48h post Salmonella infection. Therefore under our experimental conditions, exposure to a medium concentration of FB 1n naturally contaminated food had no effect on the p1g health but can affected the digest1ve nora equillbnum , the Salmonella exposure amplifying th1s phenomenon