Immunization with recombinant alpha toxin partially protects broiler chicks against experimental challenge with Clostridium perfringens
ABSTRACT Necrotic enteritis (NE) in poultry has re-emerged as a concern for poultry producers, due in part to banning, by many countries, of the use of antimicrobial growth promoters in feeds. This re-emergence has led to a search for alternative methods for control of the disease, particularly vaccination. The objective of this work was to determine if vaccination of broiler chicks with recombinant alpha toxin protected against experimental challenge. Broiler chicks were vaccinated subcutaneously at 5 and 15 days of age, followed 10 days later by challenge with Clostridium perfringens. Birds were challenged twice daily on 4 consecutive days by mixing C. perfringens cultures with feed (three parts culture: four parts feed). Non-vaccinated birds challenged with C. perfringens developed NE at the rate of 87.8%, while only 54.9% of vaccinated birds developed lesions. In addition, non-vaccinated birds had lesion scores averaging 2.37, while average scores in vaccinated birds were 1.35. Vaccination produced an antibody response, with post-vaccination anti-alpha toxin IgG (IgY) titers in vaccinated birds more than 5-fold greater than in non-vaccinated birds. After challenge, vaccinated birds had average IgG (IgY) titers>15-fold higher than those in non-vaccinated birds. These results suggest that alpha toxin may serve as an effective immunogen, and, as such, may play a role in pathogenesis.
Full-textDOI: · Available from: Hien Trinh, Jul 10, 2014
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- "According to different publications, wet litter is often linked to an altered digestive function and is often identified as a consequence of the clinical and subclinical forms of necrotic enteritis. This is our primary hypothesis to explain the higher litter moisture in our drug-free flocks at the end of the growing period (Abildgaard et al., 2010b; Barri and Smet, 2011; Cooper et al., 2009; Smith, 2011; Teirlynck et al., 2011; van der Hoeven-Hangoor et al., 2013). Wet litter is not only associated with secondary health problems in poultry flocks such as footpad dermatitis, cellulitis, and animal welfare, but can also influence the bacterial community found within a specific house (Abildgaard et al., 2010b; Schrader et al., 2004; Shepherd and Fairchild, 2010; van der Hoeven-Hangoor et al., 2013). "
ABSTRACT: The use of antimicrobial agents as feed additives in poultry production is a public health concern due to the overall increase in antimicrobial resistance. Although some alternative products are commercially available, little is known on their potential impact on flock health and productivity. A prospective study involving 1.55 million birds was conducted on eight commercial broiler farms in Québec, Canada, to evaluate the impact of replacing antibiotic growth promoters and anticoccidial drugs by a drug-free program including improved brooding conditions, anticoccidial vaccination, essential oil-based feed additives, and water acidification. Various productivity and health parameters were compared between barns allocated to the conventional and the drug-free program. Zootechnical performances were monitored as productivity criteria. Clinical necrotic enteritis and subclinical enteritis occurrences, litter and fecal moistures content were measured, and microscopic gut health was evaluated. Clostridium perfringens and Campylobacter spp. strains were recovered from fecal samples collected during farm visits. Clostridium perfringens counts were used as poultry health indicators and Campylobacter prevalence was noted as well. The drug-free program was associated with a significant increase in feed conversion ratio and a decrease in mean live weight at slaughter and in daily weight gain. An increased incidence of necrotic enteritis outbreaks and subclinical enteritis cases, as well as an increase in litter moisture content at the end of the rearing period were also observed for this program. Mean microscopic intestinal lesion scores and prevalence of Campylobacter colonization were not statistically different between the two groups but the drug-free program was associated with higher Clostridium perfringens isolation rates. According to the current study design, the results suggest that substitution of antibiotic growth promoters and anticoccidial drugs by a drug-free program impacts various broiler chicken production parameters and Clostridium perfringens carriage levels. © 2015 Poultry Science Association Inc.Poultry Science 06/2015; DOI:10.3382/ps/pev142 · 1.67 Impact Factor
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- "Necrotic enteritis (NE) and avian coccidiosis are important infectious diseases in commercial poultry production, both resulting in field outbreaks with substantial mortality (Lee et al., 2011a,b,c; Van Immerseel et al., 2009). NE alone costs the international poultry industry approximately 2 billion U.S. dollars annually as a consequence of medication and reduced body weight (Cooper et al., 2009; Van der Sluis, 2000). Both enteric diseases have traditionally been controlled by prophylactic in-feed antibiotics (Shirley and Lillehoj, 2012). "
ABSTRACT: This study was conducted to investigate the effects of in ovo administration of selenium (Se) incorporated into hydrolyzed soybean protein (B-Taxim [BT]) on protection against experimental avian necrotic enteritis (NE). Broiler eggs were injected with either 100 μl of PBS alone (BT0), or 20 or 40 μg/egg of BT in PBS (BT20, BT40) at 18 days of embryogenesis. On day 14 post-hatch, the chickens were uninfected or orally infected with 1.0 × 104 oocysts of Eimeria maxima (E. maxima). On day 18 post-hatch, E. maxima-infected chickens were orally infected with 1.0 × 109 CFU of Clostridium perfringens (C. perfringens). Compared with untreated and infected BT0 controls, BT20 and/or BT40 birds showed increased body weights, decreased fecal shedding of E. maxima oocysts, lower serum α-toxin and NetB levels, increased levels of serum antibodies against C. perfringens α-toxin and NetB toxin, decreased levels of serum malondialdehyde, reduced serum catalase and superoxide dismutase catalytic activities, and increased intestinal levels of gene transcripts encoding interleukin (IL)-1β, IL-6, IL-8, and peroxiredoxin-6, but decreased levels of transcripts for catalase and glutathione peroxidase. Interestingly, transcript levels for inducible nitric oxide synthase and paraoxonase/arylesterase 2 were decreased in the BT20 group and increased in the BT40 group, compared with BT0 controls. These results indicate that in ovo administration of broiler chickens with a Se-containing protein hydrolysate enhanced protection against experimental NE possibly by altering the expression of proinflammatory and anti-oxidant genes and their downstream pathways.Veterinary Parasitology 10/2014; 206(3-4). DOI:10.1016/j.vetpar.2014.10.025 · 2.55 Impact Factor
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- "For these reasons and because of the potential for the emergence of drug-resistant pathogens, recent interest has focused on developing drug-free disease strategies to control NE and to reduce the risk factors associated with NE (Lee et al., 2008, 2011, 2013). Vaccination with attenuated strains of C. perfringens or recombinant vaccines, and dietary supplementation with phytonutrients or micronutrients offer 2 such alternative approaches (Cooper et al., 2009; Jang et al., 2012; Lee et al., 2013). "
ABSTRACT: This study was conducted to investigate the effects of in ovo injection of Se on modulating the immune system and antioxidant responses in broiler chickens with experimental necrotic enteritis. Broiler eggs were injected at 18 d of embryo age with either 100 μL of PBS alone or sodium selenite (Na2SeO3) in PBS, providing 0 (SS0), 10 (SS10), or 20 (SS20) μg of Se/egg. At 14 d posthatch, PBS-treated and uninfected chickens were kept as the control group, whereas the remaining chickens were orally infected with 1.0 × 10(4) sporulated oocysts of Eimeria maxima (SS0, SS10, SS20). At 18 d posthatch, E. maxima-infected chickens were orally infected with 1.0 × 10(9) cfu of Clostridium perfringens. Infected control SS0 group showed significantly decreased BW compared with the uninfected control. However, SS20 group showed significantly increased BW compared with the infected control SS0 group, whereas the BW were similar among uninfected control and infected SS10 and SS20 groups. The SS10 group showed significantly lower intestinal lesions compared with the SS0 group, and oocyst production was decreased in both SS10 and SS20 groups. Serum malondialdehyde level and catalase activity were also decreased in both SS10 and SS20 groups, whereas the superoxide dismutase level was significantly lower in the SS10 group compared with the SS0 group. The SS20 group showed significantly higher levels of transcripts for IL-1β and IL-6 in intestine, and SS10 and SS20 groups had higher levels of transcripts for IL-8 and inducible nitric oxide synthase expression and decreased glutathione peroxidase 7 mRNA levels compared with the SS0 group. The SS10 and SS20 groups also showed increased serum antibody levels to C. perfringens α-toxin and NetB toxin compared with the SS0 group. These collective results suggest that the injection of Se into the amniotic cavity of developing eggs may be beneficial for enhancing immune and antioxidant responses in the hatched chickens exposed to the necrotic enteritis-causing pathogens.Poultry Science 05/2014; 93(5):1113-21. DOI:10.3382/ps.2013-03770 · 1.67 Impact Factor