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Title: Persistence and level of inoculated Salmonella Typhimurium in larval and adult darkling beetles.

item ROCHE, A
item Cox, Nelson - Nac
item Richardson, Larry
item Buhr, Richard - Jeff
item Siragusa, Gregory
item HINKLE, N

Submitted to: Poultry International Exposition
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/2007
Publication Date: 7/20/2008
Citation: Roche, A.J., Cox Jr, N.A., Richardson, L.J., Buhr, R.J., Fairchild, B.D., Siragusa, G.R., Hinkle, N.C. 2008. Persistence and level of inoculated Salmonella Typhimurium in larval and adult darkling beetles.. Poultry International Exposition. 87(S1):170.

Interpretive Summary:

Technical Abstract: Alphitobius diaperinus is a common litter pest in broiler houses. Both adults and larvae are regularly ingested by broilers and could serve as a vector of Salmonella to the current and subsequent broiler flocks. The objectives of this study were to evaluate the persistence of a marker S. Typhimurium in adult and larval darkling beetles and determine the level of colonization of S. Typhimurium in the beetles. In study 1, adult and larval beetles were deprived of feed for 24 h and then provided non-medicated broiler feed for 24 h that had been sprayed with a naladixic acid resistant marker strain of Salmonella Typhimurium at either a high (106 cfu/mL), medium (104 cfu/mL), or low (102cfu/mL) inoculation level. The beetles were then moved to a sterile container with non-inoculated feed. Individual (n=10) and pooled samples (n=1) of the adult and larval beetles, along with the feed, were sampled up to 63 d for adults and up to 36 d for larvae. In study 2 pooled adult (n=4) and larval (n=4) beetles were sampled to determine the level of Salmonella over 6 wks. After each sampling time, beetles were moved into a new container and fresh feed was added. In study 3, larvae were inoculated and allowed to pupate then sampled. In study 1, persistence lasted up to 63 d (20% positive) at the high inoculation, 27 d at the medium inoculation (pooled positive), and 9 d at the low inoculation (10% positive). In the beetle larvae, the Salmonella persisted for up to 37 d (end of sampling) in the high inoculation (70%), and up to 21 d in the medium (100%) and low inoculation (80%). In study 2, the level of Salmonella for the adult beetles ranged from 102 to 107 CFU over 6 wks and averaged 104 at 40 d of sampling. For the larval beetles, the level ranged from103 to 105 CFU over 6 wks and averaged 105 CFU at 30 d of sampling. From study 3, 45% of the larvae were positive for the marker Salmonella following pupation. These data suggest that Salmonella can persist in adult and larval darkling beetles for sufficient time to colonize subsequent broiler flocks and can be positive after pupation.