J APPL POULT RES 2007. 16:397-403
© 2007 Poultry Science Association
Effect of Dietary Mannan Oligosaccharide (Bio-Mos) on Live Performance of Broiler Chickens Given an Anticoccidial Vaccine (Paracox) Followed by a Mild Coccidial Challenge
L. Nollet*,1,
G. Huyghebaert
and
P. Spring
* Alltech Netherlands, 2982 CM Ridderkerk, the Netherlands; Institute for Agricultural and Fisheries Research (Centre for Agricultural Research), Animals Science Unit, 9090 Melle, Belgium; and Swiss College of Agriculture, 3052 Zollikofen, Switzerland
Correspondence: 1 Corresponding author: Lnollet{at}alltech.com
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SUMMARY
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A pen trial with 720 Ross 308 male chicks evaluated effects of Paracox-5 vaccination at d 1, dietary mannan oligosaccharide (MOS; Bio-Mos at 2, 1, and 0.5 kg/tonne in starter, grower, and finisher, respectively), and d-15 Eimeria challenge on d-22 lesions and 1 to 42-d live performance. Available floor area in each of 24 floor pens was 2.1 m2, and 30 chicks were placed per pen initially. A 3-phase feeding program was used: starter (0 to 15 d), grower (16 to 22 d), and finisher (23 to 42 d). The 4 dietary and vaccine treatments were as follows: 1) without vaccination, dietary MOS, or coccidiosis challenge; 2) without vaccination and dietary MOS but with a 3-strain pathogenic Eimeria challenge; 3) with Paracox-5 vaccination and Eimeria challenge but no dietary MOS; and 4) with Paracox vaccination, dietary MOS, and Eimeria challenge. The pathogenic Eimeria sporulated oocysts mixture from the French National Institute for Agricultural Research (Paris, France), standardized and well-defined, was given via feed at d 15 (100,000 Eimeria acervulina, 10,000 Eimeria maxima, and 15,000 Eimeria tenella per bird). Coccidiosis lesion scores were recorded at 22 d of age (scored as 0, 1, 2, or 3 with increasing severity). Overall mean lesion scores (P < 0.001) were higher in challenged birds. Paracox-5 alone improved 15-d BW and 1 to 15- and 15 to 22-d average daily gain of Eimeria-challenged broilers (P < 0.05). Dietary MOS improved (P < 0.05) 15 to 42- and 22 to 42-d FCR of Paracox-5 vaccinated, Eimeria-challenged broilers. Mortality was 4.4 to 5.8% by treatment, with no significant differences. It was concluded that dietary MOS improved the feed conversion ratio of Paracox-5-vaccinated (d 1), challenged (d 15) broilers from 15 to 42 d of age.
Key Words: broiler • coccidiosis vaccine • lesion score • mannan oligosaccharide • Paracox-5
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DESCRIPTION OF PROBLEM
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Coccidiosis remains a costly chicken parasitic disease due to its prevention and incidence-related expenses in spite of many scientific advances. With the recent increased emphasis on nondrug production of broiler chicken, live anticoccidial vaccines have been increasingly substituted for chemical and ionophore coccidiostats. Live vaccines are primarily utilized for large broilers, destined for use in further-processed meat, because these birds can attain compensatory growth by market age. They can also be utilized as part of a revitalization to restore a coccidiostat-sensitive population of oocysts, get improved live performance in a postbreak flock, or both. Uniform vaccine application to each broiler chick is essential and results in minimal lesion development similar to that in birds given anticoccidials in feed [1].
Results of the first large-scale broiler trials under commercial conditions with Paracox [2], a live attenuated anticoccidial vaccine administered in the drinking water, were reported in 1999 [3]. The vaccine contains 7 of the 9 species of Eimeria that parasitize chickens. The authors concluded that the use of Paracox vaccine may control clinical coccidiosis and also achieve live performances at least equal to anticoccidial drugs (i.e., halofuginone then salinomycin, or nicarbazin then monensin), particularly where drug resistance might result in failure to control disease. In 2002, an Italian trial concluded that Paracox was a suitable replacement for a nicarbazin-monensim anticoccidial shuttle program for broiler chickens [4]. In 2003, Paracox-5 vaccine was administered at d 1 to broiler chicks that were challenged 28 d later with 3 virulent Eimeria strains. Protection due to vaccination was demonstrated against coccidiosis-associated reduction in weight gain and lesion formation, and feed conversion ratio was improved [5].
Some intestinal damage occurs following inoculation with live coccidia strains and opportunistic Clostridia often proliferate in the mucus generated by the damaged intestine [6, 7]. Some ionophore anticoccidial drugs, such as narasin, possess anticlostridial activity, and removal of those ionophores from broiler feeds may increase Clostridia numbers [8]. High Clostridia counts in the intestinal tract (feces) and litter may be related to higher incidences of gangrenous dermatitis, necrotic enteritis, and mortality and is reported to be an emerging threat to human health [9]. The use of live coccidia for immunity development against later coccidial challenges may impair feed conversion ratio to an extent because of some intestinal damage. Cecal coccidiosis has been shown to result in a proliferation of cecal Clostridia and Enterobacteria (coliforms) and a decline in lactic acid-producing bacteria (lactobacilli and bifidobacteria) [10].
Therefore, it is essential that coccidial lesions be minimized and immunity maximized. Dietary supplementation with mannan oligosaccharide (MOS) may be beneficial, in conjunction with live coccidia vaccines, by acting as a general intestinal immune modulant. It works by adversely affecting Clostridia that reside near the intestinal wall and as a binding site for certain pathogenic bacteria (e.g., Escherichia coli and Salmonella with type 1 fimbrae and mannose-seeking lectins) [11]. Mannose residues exposed on glycoproteins present at the gut epithelial cell surface form important attachment sites for several unfavorable organisms. Mannose itself is relatively inefficient, but yeast cell wall-derived mannoproteins are potentially very effective at blocking type 1 fimbrae docking sites [12]. Sheng et al. [13] stated that mannan isolated from yeast binds to C-type lectins of the mannose receptor family expressed by antigen-presenting cells including dendritic cells and macrophages. As the receptors mediate endocytosis, they have been targeted with ligands to deliver antigens into antigen-presenting cells to initiate immune responses. Cox et al. [14] described mannosereceptor-binding mannan as one of several mucosal adjuvants capable of inducing protective immune responses and important in the development of mucosal vaccines and vaccination strategies.
Flock health, or more specifically, gut health, is the most important contributor to optimal performance. To be sustainable, a growth-promoting gut health program needs to be holistic and include intervention at host, agent, and environmental levels. The efficiency of nutrient assimilation (intake, digestion, and absorption), and hence feed efficiency, is dependent on the integrity of the absorptive membrane, which is in turn dependent on the gut lumen environment. Antigen-induced inflammation of the gut epithelium stimulates an increase in mucus secretion, barrier permeability, and feed passage (peristalsis and fluid secretion). Immune modulation can be used to carefully manage the balance between disease resistance and tolerance to maintain productivity. A dietary additive such as MOS, which enhances the protective antibody response to enhance disease resistance while at the same time suppressing the acute phase (fever) response, is unique and particularly useful in this regard [15].
Tizard et al. [16] reviewed the biological activities of mannans and related complex carbohydrates and indicated that they inhibit cholesterol absorption, bind to mannose-binding proteins, induce macrophage activation and interleukin-1 release, inhibit viral replication, stimulate bone marrow activity, promote wound healing, and inhibit tumor growth.
The objective of this trial was to evaluate the effect of MOS on coccidial lesion scores and live performance of broiler chickens vaccinated with a live coccidiosis vaccine and challenged with a mixture of 3 pathogenic strains of sporulated Eimeria oocysts. In the case of coccidiosis vaccination followed by pathogenic coccidia challenge, dietary MOS may act to ensure optimal initial gut health, mucosal immune response, Clostridium perfringens suppression, and accelerated healing of coccidial and secondary clostridial wounds in the intestinal wall.
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MATERIALS AND METHODS
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Birds, Housing, and Vaccination
A total of 720 Ross 308 male broiler chicks [17] were raised in floor pens with wood shavings, divided over 4 treatments with 6 repetitions per treatment. The birds were housed 30 per pen at placement with a total available floor area of 2.1 m2 per cage. The trial was conducted at the Institute for Agricultural and Fisheries Research, Animal Science Unit, Melle, Belgium in March to April 2006 with approval of the animal care committee. Infrared bulbs (1 per pen) and central heating by hot water pipes provided optimal house temperature. The lighting program was 23L:1D during the entire period. There was mechanical ventilation with an air entrance centrally at the top of the building and air extraction at both sides. The ventilation rate depended on the measured temperature and age of the broilers to minimize the moisture, NH3, and CO2 content of the inside air.
The chicks were vaccinated at 1 d of age against Newcastle disease (NDW spray) and bronchitis (Poulac IB Primer spray). At 16 d of age, the vaccination against Newcastle disease was repeated with La Sota (Clone 30 via drinking water).
Experimental Treatments
A 3-phase feeding program was used: starter (0 to 15 d), grower (15 to 22 d), and finisher (22 to 42 d). At 15, 22, and 42 d (end of each feeding period), BW, feed conversion ratio (FCR), and mortality were measured.
The feed was based on wheat, corn, soybean meal, and heat-treated full-fat soybeans plus supplemental Met, Lys, and Thr. Crude protein (%) and ME (MEn, kcal/kg) levels in the 3 feed phases were as follows, respectively: starter, 20.9 and 2,770; grower, 20.4 and 2,902; and finisher, 19.5 and 2,997. The 4 dietary and vaccine treatments (no coccidiostats in feed) were as follows: 1) without vaccination, dietary MOS, or coccidiosis challenge; 2) without vaccination and dietary MOS but with a 3-strain pathogenic Eimeria challenge; 3) with Paracox-5 vaccination at hatch and Eimeria challenge but no dietary MOS; and 4) with Paracox-5 vaccination at hatch, dietary MOS, and Eimeria challenge. Dietary MOS [18] was included at 2 kg/tonne in starter, 1 kg/tonne in grower, and 0.5 kg/tonne in finisher. No coccidiostats were included in any of the broiler feeds.
Live Performance
Average pen weights were recorded at 1 (placement), 15, 22, and 42 d of age. Feed intake was recorded for 1 to 15-, 15 to 22-, and 22 to 42-d periods. Averaged daily gains and FCR were calculated for 1 to 15-, 1 to 22-, 22 to 42-, 15 to 42-, and 1 to 42-d periods. Feed conversion was adjusted for mortality. Mortality and culls were recorded for the entire trial, 1 to 42 d. The live performance data were subjected to ANOVA and least significant difference-multiple range test [19, 20]. Before ANOVA, mortality plus culls and coccidial lesion score data were arcsine-square root transformed by using the following procedure: arcsine degrees = arcsine radians [square root (percentage or score/100)] x 180/3.1417.
Coccidial Challenge and Lesion Scoring
A challenge with a mixture of sporulated oocysts of pathogenic strains of Eimeria (100,000 Eimeria acervulina, 10,000 Eimeria maxima, and 15,000 Eimeria tenella per bird) was done on d 15 through the feed (i.e., at the end of the starter period) after the 15-d weight and FCR determination. The Eimeria mixture obtained from the French National Institute for Agricultural Research, Paris, France, was standardized and well-defined and has been used in several trials for registration purposes of some chemical and ionophoric coccidiostats within the European Union.
After challenge on d 15, coccidial lesion scoring was carried out on d 22 using the method of Johnson and Reid [21]. On d 22 (i.e., end of the grower period), three birds per cage that appeared to be close to average pen weight were randomly selected, weighed, necropsied, and the intestinal tract was examined for coccidial lesions by the veterinary service of the Governmental Animal Health Care Center (Lier, Belgium). Lesion scores were recorded as 0, 1, 2, or 3, from least to most severe. Lesions typical for each of the 3 types of Eimeria were recorded separately.
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RESULTS AND DISCUSSION
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BW and Mortality Plus Culls
Body weight results at d 1, 15, 22, and 42; lesion scores at d 22; and 1 to 42-d total mortality plus culls are summarized in Table 1
. The 1-d-old birds were of good quality. The d-15 BW was higher for the Paracox-5-vaccinated, pathogenic coccidiosis-challenged chicks (treatment 3) than for the unvaccinated challenged birds (treatment 2). However, the d-42 BW was not significantly different between treatments. Williams and Gobbi [4], however, reported that Paracox-vaccinated broiler chickens were significantly heavier at 36 or 37 d for females or 56 d for males compared with those protected with nicarbazin and monensin coccidiostats in a 3-crop trial.
Total mortality plus culls percentages ranged from 4.44 to 5.81 and were not significantly different between treatments (Table 1
). These means indicate a mild coccidial challenge (compared with 4.44% mortality without challenge), and figures are still similar to those in the commercial broiler industry. Williams et al. [3] evaluated Paracox vaccine administered in water and found mortality to be 3.0% in vaccinated and 3.8% in halofuginone then salinomycin or nicarbazin then monensin-medicated broilers (P < 0.001). Culled birds were 4.0% in vaccinated and 3.8% in anti-coccidial-medicated flocks (not significantly different).
Average Daily Gain
Average daily gain (g/d) of broiler chickens during various phases of growth are presented in Table 2. The 1 to 15- and 15 to 22-d average daily gains were higher for the Paracox-5-vaccinated, pathogenic coccidiosis-challenged chicks (treatment 3) than for the unvaccinated, challenged birds (treatment 2). The Eimeria challenge at 15 d provoked significantly lower 15 to 22-d average daily gains showing the challenge worked well, giving a mild (about 10%) growth depression.
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Table 2. Average daily gain of broiler chickens from 1 to 15, 15 to 22, 22 to 42, 1 to 22, 15 to 42, and 1 to 42 d by experimental treatments
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FCR
Feed conversion ratio results by treatment are given in Table 3. During 15 to 42 and 22 to 42 d in coccidiosis-challenged broilers, Paracox-5 vaccination alone (treatment 3) significantly worsened FCR, whereas Paracox-5 plus dietary MOS (treatment 4) brought FCR to as good or better than the unvaccinated, unsupplemented birds (treatment 2). Therefore, dietary MOS was beneficial in improving FCR of Paracox-5-vaccinated, coccidiosis-challenged broilers during the 15 to 42-d period (compare treatment 3 vs. treatment 4).
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Table 3. Feed conversion ratio of broiler chickens from 1 to 15, 15 to 22, 22 to 42, 1 to 22, 15 to 42, and 1 to 42 d by experimental treatments
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Williams et al. [3] found that the FCR of Paracox-vaccinated broilers was 2.01 compared with 1.96 for halofuginone then salinomycin or nicarbazin then monensin-medicated birds (P = 0.025). This indicates about 0.05 poorer FCR in Paracox-vaccinated birds. In the present trial without coccidiostats, 22- to 42-d-old broilers vaccinated with Paracox-5 had 0.057 poorer FCR when challenged (treatment 3) than when unvaccinated and challenged (treatment 2). This is probably due to gut wall damage in which resorption of nutrients is not optimal and repair of the gut wall required energy and protein, which can then not be used for growth.
Coccidiosis Lesion Scores
Coccidiosis lesion scores (0 to 3, least to most severe) at d 22 were significantly different between the coccidiosis unchallenged (treatment 1) and challenged treatments (treatments 2 to 4) for E. tenella lesions and overall averages (Table 4).
Crouch et al. [5] demonstrated that Paracox-5 administered to broiler chicks at d 1 protected birds that were challenged 28 d later with Eimeria species (acervulina, maxima, mitis, or tenella) against coccidiosis-associated reduction in weight and lesion formation. Additionally, Paracox-5 provided protection against a mixed virulent Eimeria challenge introduced by seeder birds 21 d after vaccination. Newman [1] emphasized that uniform vaccine administration results in minimal lesion development, similar to lesions that occur when flocks are fed low-level ionophores in the diet. However, when the vaccine is administered in unequal doses per bird (nonuniformly), susceptible birds may develop excessive lesions or clinical coccidiosis that is due to infection with either the field strains or vaccine strains.
It has been demonstrated that dietary MOS can reduce certain enteric pathogens such as some strains of Salmonella, E. coli, and Campylobacter by blocking the type 1 fimbrae that enable these pathogens to attach to the intestinal lining [22, 23]. Generally, Clostridia species and Campylobacter jejuni do not agglutinate MOS, but individual isolates have been identified with weak agglutinating properties, independent of mannose inhibition, suggesting other mechanisms of bacterial adhesion [24]. Spring et al. [22] showed that dietary MOS significantly decreased the number of Salmonella-positively infected chicks at 10 d old and tended (P < 0.10) to lower counts of cecal coliforms in young chicks challenged with Salmonella at 3 d old.
Use of dietary MOS during a coccidiosis challenge may act, through Clostridia suppression, to prevent secondary infection. Although Clostridia do not express type 1 fimbrae, Hofacre [25] reported that supplementing MOS to diets of broilers challenged with Clostridia had some effects in reducing mortality as well as improving FCR. Combined use of C. perfringens and pathogenic coccidia challenge (for example, with E. maxima [6] or E. acervulina and Eimeria necatrix [7]) is an experimental model for producing necrotic enteritis. Finucane et al. [26] noted that dietary MOS was comparable to bacitracin methylendi-saliscylate for improving 49-d BW gain and FCR of turkeys. Mortality was lowest in the MOS treatment group, and subsequent examination of intestinal microflora of these turkeys indicated an increase in total anaerobes and a decrease in C. perfringens concentrations. The mode of action by which MOS interacts with Clostridia to lower counts is not fully clear, but in broiler chickens, dietary MOS has been shown to improve intestinal function or gut health (for example, increased villi height, uniformity, and integrity) [27]. This had been summarized by Hooge [28] from a meta-analysis of dietary MOS (Bio-Mos) broiler chicken trials that were conducted globally from 1993 to 2003. The meta-analysis compared MOS to nonsupplemented controls and showed that MOS-fed broilers had relative improvements of +1.61% in BW, –1.99% in FCR, and –21.4% in mortality.
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CONCLUSIONS AND APPLICATIONS
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- Challenging broiler chickens at 15 d of age with a mixture of 3 strains of Eimeria significantly worsened 15 to 22-d average daily gain, 1 to 22-d and 15 to 22-d FCR, and 22-d overall coccidiosis lesion scores compared with unchallenged birds.
- Administering Paracox-5 live attenuated anticoccidial vaccine at d 1 significantly improved BW at d 15 and average daily gain from 1 to 15 and 15 to 22 d in Eimeria-challenged broilers compared with unvaccinated, challenged broilers.
- The d-1 Paracox-5-vaccinated, MOS-supplemented, challenged broilers had 15 to 42- and 22 to 42-d FCR significantly better than Paracox-5-vaccinated, unsupplemented, challenged broilers. Dietary MOS (2, 1, and 0.5 kg/tonne) can therefore be considered beneficial in combination with Paracox-5 vaccination.
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ACKNOWLEDGMENTS
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We wish to thank Monita Vereecken from the Governmental Animal Health Care Centre of Flanders (Diergezondheidszorg Vlaanderen Vzw), Lier, Belgium, for the coccidiosis lesion scoring.
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REFERENCES AND NOTES
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- Newman, L. J. 1999. Coccidiosis control with vaccine: Been there, done that. Or have we? Pages 52–55 in Arkansas Poult. Symp., Springdale, AR.
- Schering-Plough Animal Health, Harefield, Uxbridge, Middle-sex, UK
- Williams, R. B., W. W. Carlyle, D. R. Bond, and I. A. Brown. 1999. The efficacy and economic benefits of Paracox, a live attenuated anticoccidial vaccine, in commercial trials with standard broiler chickens in the United Kingdom. Int. J. Parasitol. 29:341–355.[ISI][Medline]
- Williams, R. B., and L. Gobbi. 2002. Comparison of an attenuated anticoccidial vaccine and an anticoccidial drug programme in commercial broiler chickens in Italy. Avian Pathol. 31:253–265.[ISI][Medline]
- Crouch, C. F., S. J. Andrews, R. G. Ward, and M. J. Francis. 2003. Protective efficacy of a live attenuated anti-coccidial vaccine administered to 1-day-old chickens. Avian Pathol. 32:295–302.
- Williams, R. B., R. N. Marshall, R. M. La Ragione, and J. Catchpole. 2003. A new method for the experimental production of necrotic enteritis and its use for studies on the relationships between necrotic enteritis, coccidiosis and anticoccidial vaccination of chickens. Parasitol. Res. 90:19–26.[ISI][Medline]
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- Hofacre, C. I. 2001. Necrotic enteritis, currently a billion dollar disease: Is there anything new on the horizon? Pages 79–86 in Biotechnology in the Feed Industry, Proc. Alltech’s 17th Annu. Symp. T. P. Lyons and K. A. Jacques, ed. Nottingham Univ. Press, Thrumpton, Nottingham, UK.
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SUMMARY
DESCRIPTION OF PROBLEM
