It is well known that two of the most common microorganisms associated with food-borne illnesses are Campylobacter jejuni and Salmonella serotypes which are readily found in poultry house environments.Poultry products have been repeatedly implicated as a significant source of food-borne disease organisms.This has researchers examining methods of reducing bacteria at the farm level.The primary focus of this study will be on novel pre-harvest methods to control food-borne bacteria in poultry.Four studies were conducted to examine the potential of using mannose or peptide-containing biofunctionalized nanoparticles (BN) to bind Campylobacter jejuni (C) in vitro or in the gastrointestinal (GI) tract of poultry.Two additional studies were conducted to examine the effects of two feed additives, Immustim® and Protimaz®, on growth performance and bacterial pathogen populations in the lower GI tract and ceca of broiler chickens.The objective of the preliminary tolerance study was to determine the effect of the BN polystyrene cores on turkey poult performance to 6wk with observation to 14wk.In this study, 198 1-wk old Nicolas turkey poults placed in 6 pens were banded, weighed and then gavaged with varying volumes (0.1, 0.5 or 1.0mL) of different polystyrene core aqueous suspensions.In all pens, 3 control poults were gavaged with distilled water.BW was determined at wk 1, 3 and 6 with observations to 14 wk.There were no significant differences (P≤0.05) in BW or BW gains due to the polystyrene cores.Thus, the cores were apparently tolerated by the turkey poults and did not impact growth performance.The second study utilized an in vitro protocol to examine BN-bacterial aggregation activity.Aqueous BN suspensions were diluted 1:1, 1:10 and 1:100 in 0.1% peptone water, mixed with 1.5mL of suspended C and incubated at room temperature.The mixtures were sampled at 5 and 30 minutes, plated onto Brucella agar and incubated at 42°C for 48h.Population reductions were observed between the control and BN and C mixtures for BN treatments #1 and #2 (P≤0.05 and P≤0.10, respectively) though it was not determined if the reductions were due to cell aggregation or cell death.The third and fourth studies evaluated the effect of BN and mannose solutions on C colonization in vivo.In study 3, fifteen 10-wk old broilers (Ross 308 feather sexable females x Ross males, AviagenTM) were placed in individual growth cages.Five experimental treatments (3 birds/treatment) were evaluated: a control (no treatment); 1 or 2 mL gavage of BN; and 1 or 2 mL gavage of a 10% mannose solution.The birds were sacrificed 24h after gavage and fecal, cecal and GI samples aseptically taken and C populations estimated.No significant differences in C populations were detected between the control and BN treatments for the cecal, GI or fecal samples (P≥0.05).However, the GI tract C populations recovered following the mannose treatments were significantly higher than the control populations (P≤0.10).In addition, it was observed that when the mannose concentration was increased to 20%, fecal C populations declined by 0.73 log (P= 0.09).Study 4 (3d duration) was divided into 2 trials.Four, 4-wk old control broilers (Ross 308 feather sexable females x Ross males) received no oral treatment, whereas 16 experimental birds (4/cage) were orally gavaged with 1 of 4 BN treatment doses (1, 2, 4 or 8mL) on d2.Trial 2 consisted of 2 treatment groups (16 birds/treatment, 4 birds/cage):MIX (a mixture of 1 mL/bird of 105 CFU/mL of C and 1, 2, 4 or 8mL of BN) and CBN (1 mL/bird of 105 CFU/mL C- challenge prior to administering 1, 2, 4 or 8mL of BN).On d1, both the MIX treatment and the C-challenge of the CBN treatment were administered.The varying volumes of BN were gavaged on d2 (CBN treatment).On d3, all birds were euthanized and samples (fecal, cecal and GI) were aseptically taken, blended, diluted, plated (50μL) onto Campy Cefex® agar and incubated.In trial 1, no significant differences in C populations were observed between the BN and control treatments (P≥0.05).In trial 2, significant differences in C populations recovered from the ceca and GI were detected between the pooled MIX and CBN treatment data (P≤0.05).Moreover, treatment dose also influenced the recovery of fecal C populations for both the MIX and CBN treatments (P≤0.05).Overall, the results from the BN trials showed both increases and decreases in C populations.However, any increase or decrease in populations is subject to a great deal of speculation as to the BN's exact mechanism of action.Additional testing is warranted to further define the specific effects of BN on C populations in vivo.The first objective of this experiment was to reduce the populations of S. Typhimurium (S) and C in the gastrointestinal (GI) tract of broilers by feeding a diet supplemented with either a beta-1,3⁄1,6-glucan (Immustim®) or a spray-dried egg product from hens immunized against Salmonella (Protimax®) on intestinal S and C populations.The second objective was to evaluate the impact of feeding these dietary supplements on broiler performance to 21d or 28d. To accomplish these objectives, two studies were conducted consisting of the same experimental design.Male broiler chicks (600, Ross 308 feather sexable females x Ross males) were placed at 10 per pen (12 pens⁄battery) in 3 rooms (2 batteries⁄room).C- and S-challenged and non-challenged control chicks were housed in separate rooms.Pens were randomly assigned one of three feed treatments added to a standard starter feed.Dietary Immustim® levels were 0, 20 or 40g⁄ton.Feed treatments for the second study consisted of a negative control (a standard starter feed), a positive control (a spray-dried egg product without immunoglobulins) and Protimax® (both fed at 6kg⁄ton).In study 1, chicks were gavaged at 3d with 1mL of a 106 CFU⁄mL culture of a nalidixic acid-resistant S strain, and at 14d, with 1mL of a 106 CFU⁄mL culture of C.Lower GI tract and cecal samples (tissue and contents) were collected on 7, 14, 17 (C only) and 21d.In study 2, chicks were gavaged with the same S strain at 7d and C at 14d.Lower GI tract and cecal samples were aseptically collected on 14, 21 and 28d.The samples were serially diluted in 0.1% peptone water and spiral plated (50μL) onto Brain Heart Infustion (BHI) agar, BHI agar with 800ppm nalidixic acid and Campy Cefex® agar.Control sample plates and those plates used in estimating S populations (BHI with nalidixic acid) were incubated at 37°C for 24h while Campy Cefex® plates were incubated at 42°C for 48h under microaerophilic conditions.Data were analyzed using the GLM procedures of SAS with means separated using LS Means (P≤0.05).Neither feed treatment affected broiler GI tract S or C populations.However, improved bird performance (from 633g to 690g) was observed for non-challenged birds fed Immustim®.Moreover, S-challenged birds also showed improvement in body weight (from 635g to 691g) and feed conversion (from 1.62 to 1.44) at 20g/ton of Immustim®, while birds challenged with C showed improved FC (from 1.69 to 1.45) when fed 40g⁄ton.The addition of Protimax® resulted in reduced bird growth (from 805g to 770g) for C-challenged birds.However, Protimax® improved cumulative FC (from 1.27 to 1.20) for S-challenged birds, but had a negative impact on non-challenged and C-challenged birds.Overall, supplementing with dietary Immustim® was more effective and had a greater impact on bird performance than did Protimax®.
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Novel Pre-Harvest Approaches to Control Enteric Food-Borne Bacteria in Poultry
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