As published in Salmonella remains the top cause of both hospitalization and death from foodborne illness in the U.S. Although Salmonella can be found in the environment and many other food sources, poultry products remain a significant source of salmonellosis. An important way to help control Salmonella infection in people is to reduce the prevalence and/or load of the pathogen in the poultry flock prior to processing. Research Update Research shows Original XPC TM reduces Salmonella load and improves body weight and feed conversion in challenged turkeys Research has shown that feeding Original XPC TM to poultry can significantly reduce the pre-harvest prevalence and load of the foodborne pathogen Salmonella (McIntyre et al., 2013; Ibukic et al., 2012; Broomhead, 2014; McIntyre, 2013). The purpose of the current study was to inoculate very young turkeys with a serovar commonly associated with early contamination of live birds (Salmonella Typhimurium), then inoculate birds in the same group when older with a serovar more associated with recent human illness outbreaks (S. Heidelberg). The results would indicate whether feeding Original XPC throughout an 84d turkey hen grow-out period would be effective in reducing Salmonella shedding and colonization in turkey hens challenged with Salmonella at two ages (Day 1 and Day 56). Trial Design Don McIntyre, Ph.D., PAS Director, North America Poultry Research & Technical Service Diamond V Stephanie Frankenbach, Ph.D. Poultry Technical Specialist Diamond V A study was conducted with Southern Poultry Research Group (SPRG) in Georgia, using 1,440 female turkeys. Birds were allocated to one of two feed treatments, with and without Original XPC (Table 1). A three-phase feeding program included Pre-Starter, Starter, and Grower diets all without medication (Table 2). No vaccinations were administered at the Sep - 14 Diamond V 1
hatchery; upon arrival at SPRG, all birds were spray-vaccinated with Immuocox-T (Ceva, Lenexa, KS). Birds and feed were weighed by pen at 0, 35, 56, and 84 days of age. Boot-sock samples (one swab per pen) were collected from all pens to determine environmental Salmonella on days 14, 56, and 70. Ceca were collected from 10 non-challenged (horizontal [non-tagged]) birds per pen on days 42 and 84 to determine cecal colonization. Table 1. Treatments and experimental design Treatment Product 1 Cocci- Vaccine 1 None Day 0 2 XPC, 2.5 lb/ton 2 Day 0 Salmonella Challenge (20 birds/pen) Pen Bootsock Samples Day 0 3 Day 14 Day 56 4 Day 56 Day 70 Day 0 3 Day 14 Day 56 4 Day 56 Day 70 Ceca 5 Collection Day 42 Day 84 Day 42 Day 84 Total Birds 6 720 720 1 Diamond V Original XPC TM, Diamond V, Cedar Rapids, Iowa 2 Inclusion rate fed through day 84 (pre-starter/starter/grower diets) 3 Day 0: 1 ml/bird Salmonella Typhimurium (rifampin-resistant) broth containing approximately 10 5 cfu/ml 4 Day 56: 1 ml/bird Salmonella Heidelberg (nalidixic acid-resistant) broth containing approximately 10 8 cfu/ml 5 Collected from 10 non-challenged poults per pen 6 Birds were allocated to 12 pens per treatment, 60 birds per pen Table 2. Feeding program to turkey hens Feed Age Fed (d) ME (kcal/lb) Crude Protein (%) Pre-Starter 0 34 1,288 28.0 Starter 35 56 1,348 26.0 Grower 57 84 1,368 23.0 Salmonella Challenge Turkey poults were housed in concrete floor pens (10 ft x 10 ft) with approximately 4 inches of fresh pine shavings for bedding at placement. At 1d, 20 birds per pen in each treatment group were tagged for identification and orally gavaged with rifampin-resistant Salmonella Typhimurium. On 56d, 20 birds per pen in treatment groups 1 and 2 that were not previously challenged were tagged for identification and orally gavaged with nalidixic acid-resistant Salmonella Heidelberg. The 20 remaining birds per pen were not tagged or challenged but were used to test for Salmonella exposure due to contact with pen mates. Sep - 14 Diamond V 2
Results and Discussion The addition of Original XPC (2.5 lb/ton) to the test diets significantly improved body weight gain by 0.72 lb and improved feed conversion by 5 points in T2 turkeys at 84d (Tables 3 and 4). Table 3. Effects on turkey hen body weight by feeding Original XPC (T2-T1) Body Weight (lb) 35 d 56 d 84 d T1: No Additive 3.82 6.96 11.82 b T2: XPC (2.5 lb/ton) 3.89 7.18 12.54 a Difference (lb) 0.07 0.22 0.72 a,b Values with different letters are significant at P = 0.053 Table 4. Effects on feed conversion of turkey hens by feeding Original XPC (T2-T1) FCR (lb:lb) 35 d 56 d 84 d T1: No Additive 1.36 1.82 2.19 T2: XPC (2.5 lb/ton) 1.35 1.79 2.14 Difference ( P = 0.16) -0.01-0.03-0.05 At 42d, ceca samples were 15-21% positive for Salmonella. There was no difference between Original XCP-fed and control birds. All positives were considered to be S. Typhimurium. At day 84, ceca samples were 74-78% positive, with no difference between Original XPC-fed and control birds. At 84d approximately 16% of the positive samples contained S. Typhimurium that survived from the initial inoculation. Therefore, after two large inoculations, Salmonella prevalence of either serovar was similar between treatments. Numbers of Salmonella isolated from Original XPC-fed and control diet birds were significantly different (Figure 1). Original XPC decreased the geometric mean (shown). After conversion to log10 MPN (most probable number), the ceca from Original XPC birds was 0.41 logs lower than control birds, which is a 61% reduction in numbers. Sep - 14 Diamond V 3
Figure 1. Mean MPN counts of total Salmonella isolated from ceca of 84d turkeys fed a Control diet or diet containing Original XPC (2.5 lb/ton) diet a,b Values with different letters were significant at P = 0.034 1 Most probable number Another important facet of this work is shown in Figure 2, where the range of Salmonella numbers is shown. Feeding Original XPC reduced outlier birds or birds with high numbers of Salmonella compared to control birds. Control outliers ranged from 1,000 to more than 10,000 Salmonella cells per gram of cecal contents, while only one Original XPC outlier numbered in the hundreds. This result may be particularly important to the processing plant, where such birds can overwhelm the chemical controls in place and add risks such as: Carcasses or parts with high Salmonella numbers reaching the consumer, and Allowing highly infected carcasses to cross-contaminate many other pounds of product. Sep - 14 Diamond V 4
Figure 2. Box plot of the MPN/g numbers of Salmonella isolated from ceca of Control-diet and Original XPC-fed 84d turkey hens Conclusions The authors conclude that Original XPC fed to turkey hens from hatch to market age (84d) proved to be an effective pre-harvest intervention for Salmonella by significantly reducing numbers of bacteria or load in the ceca of highly challenged birds. Other recent studies have shown similar results, including a reduction in Salmonella prevalence as well as load of this pathogen in both turkeys and broiler chickens. Feeding Original XPC (2.5 lb/ton) to turkey hens improved body weight and feed conversion at 12 weeks of age Salmonella prevalence was similar following double challenge with S. Typhimurium and S. Heidelberg Feeding Original XPC (2.5 lb/ton) to turkey hens resulted in significant (P = 0.034) reduction in Salmonella load (reduced by 0.41 log10) References Broomhead, J. 2014. Effects of feeding Original XPC to broilers on Salmonella Typhimurium prevalence and load during a challenge study. Field trial reported in PoultryAdvisor, January 2014. Ibukic, M., D. Trampel, T. Frana, C. M. Logue, and J. Broomhead. 2012. Evaluation of Diamond V Original XPC for reducing cecal colonization by Salmonella Enteriditis in layer pullets. In: Proceedings of the 93rd Conference of Research Workers in Animal Diseases. Chicago, IL. (See also PoultryAdvisor, February 2013.) Sep - 14 Diamond V 5
McIntyre, D., J. Broomhead, G.F. Mathis, and B. Lumpkins. 2013. Effects of feeding Original XPC and salinomycin during a coccidia challenge in broilers. Poult. Sci. 92 (E-Suppl. 1):59-60. (See also PoultryAdvisor, April 2013.) McIntyre, D. 2013. Original XPC helps reduce Salmonella in turkey field trial. Field trial reported in PoultryAdvisor, June 2013. Copyright 2014 Diamond V. All rights reserved Sep - 14 Diamond V 6