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Effect of Roxarsone and Bacitracin Methylene Disalicylate on the Development of Immunity to Eimeria in Broilers Given a Live Coccidiosis Vaccine1
Effect of Roxarsone and Bacitracin Methylene Disalicylate on the Development of Immunity to Eimeria in Broilers Given a Live Coccidiosis Vaccine1 H. D. CHAPMAN,*^ and S. H. FITZCOYt *Department of Poultry Science, University of Arkansas, Fayetteville, Arkansas 72701, and f ALPHARMA, Inc., One Executive Drive, Fort Lee, New Jersey 07024 not significantly different from that of unchallenged birds and no lesions of Eimeria species were found in their intestines irrespective of the medication given. It is concluded that roxarsone and bacitracin methylene disalicylate do not interfere with the acquisition of immunity to Eimeria species in broilers.
(Key words: broiler, immunity, coccidiosis vaccine, roxarsone, bacitracin methylene disalicylate) 1996 Poultry Science 75:1488-1492
INTRODUCTION Live coccidiosis vaccines have been available for many years for the control of coccidiosis in chickens. Although principally used for breeder stock (broiler breeders and birds reared for table egg production), in which the development of immunity to Eimeria species is desirable, vaccines have also occasionally been employed in broilers. The commercial vaccine used for broilers (Coccivac B®)3 contains strains of Eimeria isolated in the 1950s, before the introduction of most anticoccidial drugs. It is likely, therefore, that these strains (unlike many recent field isolates of Eimeria) are sensitive to currently used compounds. For this reason, it is important that birds given the vaccine should not be receiving anticoccidial medication. The feed additives roxarsone (ROX4) and bacitracin methylene disalicylate (BMD®4) are widely used in broiler production for increased rate of weight gain and improved feed efficiency.5 Although anticoccidial activity has not been reported for BMD, ROX may have some effect against Eimeria tenella, Eimeria brunetti,
Received for publication April 19, 1996. Accepted for publication August 27, 1996. iPublished with the approval of the Arkansas Agricultural Experiment Station Director. 2 To whom correspondence should be addressed. 3 Mallinckrodt Veterinary Inc., Millsboro, DE 19966-0537. 4 3-Nitro®, BMD®, ALPHARMA Inc., Fort Lee, NJ 07024. 5 1996 Feed Additive Compendium, The Miller Publishing Co., 12400 Whitewater Drive, Minnetonka, MN 55343. 6 Cobb 500, Cobb-Vantress Inc., Siloam Springs, AR 72764. 7 American Cyanamid Co., Animal Health and Nutrition Division, Wayne, NJ 07470.
and Eimeria maxima (Morehouse and McKay, 1951; Kowalski and Reid, 1972, 1975). It is possible, therefore, that ROX may interfere with the acquisition of immunity to Eimeria species. The present experiment was undertaken to investigate the effect of ROX and BMD, utilized separately or in combination, upon the development of immunity to Eimeria in chickens reared in floor pens and given a coccidiosis vaccine.
MATERIALS AND METHODS Birds and Housing Day-old male chicks of a commercial broiler strain 6 were obtained from a local hatchery and placed on new litter (rice hulls) in a clean floor pen facility. Chicks were randomly assigned to each of 25 pens (60 birds per pen) at a stocking density of 1 bird per 0.07 m 2 . Each pen contained two tubular hanging feeders and an automatic waterer. Thermostatically controlled gas brooders and ventilation fans were used to regulate temperature, and 23 h of light and 1 h of dark was provided each day. The chicks had been vaccinated against Newcastle, Infectious Bronchitis, and Marek's disease at the hatchery. Eighty chicks from the same hatch were taken to a clean animal room and reared in a Petersime brooder to serve as susceptible controls. They were given robenidine (30 g / ton) 7 in the feed as a precaution against accidental infection.
Feed All birds were fed a corn-soybean basal ration formulated to meet the nutritional requirements of the
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ABSTRACT No significant differences in the BW, feed intake, feed conversion, or mortality of broilers that had been vaccinated at 3 d of age with a live coccidiosis vaccine were observed irrespective of whether they had been given roxarsone, bacitracin methylene disalicylate, or both drugs in the feed. The weight gain of birds challenged with a high dose of the vaccine at 51 d was
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IMMUNITY IN BROILERS GIVEN A COCCIDIOSIS VACCINE broiler chicken (National Research Council, 1994). Starter, grower, and withdrawal feeds were provided from 0 to 21, 21 to 44, and 44 to 49 d, respectively. A uniform basal ration was mixed, and aliquots were used to prepare the test diets. Samples of feed were retained from each batch and assayed for the concentration of drugs. Assays were within limits of the intended concentrations. 5
Design
Performance
Data
Composite pen BW at 21, 44, and 49 d of age and total feed consumed for each age period were recorded. Birds that died were weighed, and their weights added to pen weights for calculation of feed conversion. Data were analyzed by one-way analysis of variance using the PROC ANOVA procedure of SAS® software (SAS Institute, 1988). Means were separated and compared using Duncan's multiple range test.
Challenge
A further 6 preselected birds were removed from each pen given the same treatment (total of 30 birds) at 28 and 49 d, placed in a clean pen on new litter, and given unmedicated feed. Two days later they were weighed, and 15 of the birds were inoculated orally with 300 times the normal dose of Coccivac-B® per bird. The other 15 birds were not infected and served as unchallenged controls. Six days later all birds were weighed once more, and the gain in weight was calculated. Means were compared by Student's t test using software of the SAS Institute (1988). Birds were killed by CO2 asphyxiation, and the intestines were examined for lesions due to coccidiosis.
Susceptible
RESULTS
Birds in all treatments were vaccinated at 3 d of age by mixing two 1,000-dose vials of Coccivac-B® in tap water so that 100 mL of the resulting suspension contained the appropriate dose of oocysts for 60 birds in each pen. The hanging feeders were then elevated, and 100 mL of oocyst suspension was mixed in 1,200 g of feed. The contaminated feed was placed on trays in the pens and was consumed in about 3 h. Ten days after vaccination, amproliumS (0.006%) was provided for 48 h in the drinking water.
Birds
Birds to be used for lesion scoring and in the challenge experiments were randomly selected when weighed at 21 d and tagged with a wing-band for identification. Five preselected birds were taken from each pen at 27 d
8
Controls
Birds that had been reared in isolation in brooders were transferred to clean pens at 22 and 27 d of age. From Day 27 and 48, respectively, they were given unmedicated feed (so that robenidine was not present in the feed for 3 d prior to challenge). Subsequently, these birds were subjected to the same procedures as the birds in the principal treatments. Thus, on Day 30 and 51, respectively, 30 birds from each pen were individually weighed and 15 birds challenged, the remainder serving as unchallenged controls. Six days later all birds were weighed, killed, and their intestines were examined for coccidial lesions.
Vaccination
Preselected
Experiments
Merck AgVet Division, Merck and Co., Inc. Rahway, NJ 07065-0912.
Performance Results for the performance of birds reared in floor pens are presented in Table 1. There were no significant differences among treatments in BW, feed intake, or feed conversion for any age period.
Mortality Mean percentage mortality < SEM was 3.6 < 1.3,10.5 < 2.1, and 13.4 < 2.8, by 21,44, and 49 d of age respectively. There were no significant differences in mortality among treatments (data not given). Lesions due to Eimeria species were not seen in any of the birds that died.
Lesions in Preselected
Birds
No lesions were found in the duodenum or midintestine of birds examined at 27 d of age. Very few lesions were found in the ceca (total mean lesion score < 0.1).
Downloaded from http://ps.oxfordjournals.org/ at University of Georgia on June 5, 2015
A randomized block design was employed in which birds were given either no medication or ROX and BMD utilized separately or in combination as might be employed in commercial practice. The treatments were: 1) No medication, 2) BMD (50.0 g/ton) in the starter ration and BMD (25.0 g/ton) in the grower feed, 3) ROX (45.4 g / ton) in the starter and BMD (50.0 g/ton) in the grower, 4) BMD (50.0 g/ton) in the starter and BMD (25.0 g/ton) plus ROX (45.4 g/ton) in the grower, and 5) BMD (50.0 g/ton) plus ROX (45.4 g/ton) in the starter and BMD (25.0 g/ton) plus ROX (45.4 g/ton) in the grower feed. Birds were given no drugs (Treatment 1) or BMD (25.0 g/ton) in the withdrawal ration (Treatments 2, 3, 4, and 5).
necropsied, and the duodenum, mid-intestine, and ceca were examined for lesions due to coccidiosis (Johnson and Reid, 1970). Lesion scores for each region of the intestine were combined.
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CHAPMAN AND FITZCOY
TABLE 1. Effect of roxarsone and bacitracin methylene disalicylate upon the performance of broilers given a coccidiosis vaccine Treatment 1 Starter
Weight gain 0 to 21 d
Grower
0 to 44 d
Feed intake per bird 0 to 49 d
0 to 21 d
0 to 44 d
Feed conversion
0 to 49 d
0 to 21 d
0 to 44 d
0 to 49 d
1.380 1.432 1.443 1.429 1.443 0.016 0.136
l~.~\ yb-y 1.789 1.797 1.761 1.791 1.797 0.033 0.964
1.877 1.894 1.857 1.884 1.888 0.030 0.964
(g) N B R B B + R SEM Probability
N B B B + R B + R
732 730 731 728 742 8 0.879
2,484 2,491 2,519 2,479 2,497 29 0.912
2,842 2,799 2,851 2,825 2,814 38 0.893
1,009 1,045 1,055 1,041 1,070 14 0.130
4,443 4,476 4,434 4,430 4,485 67 0.988
5,333 5,300 5,292 5,313 5,312 69 0.986
!B = bacitracin methylene disalicylate; R = roxarsone; N = no medication were given in either the Starter or Grower feeds as indicated.
Challenged Birds
DISCUSSION No significant differences in BW, feed intake, or feed conversion were observed irrespective of whether vaccinated birds were given ROX, BMD, BMD plus ROX, or no medication in the starter and grower rations. Mortality was similar in all treatments, and coccidiosis was not observed as a cause of death in the trial. No
TABLE 2. Weight gain ± SEM and lesions present in the intestine, of broilers that had been challenged at 30 d of age with Eitneria species Treatment 1 Starter
Grower
Weight gain 2 Challenged
Lesion score 3
Unchallenged
Probability
Challenged
Unchallenged
429 432 455 449 427 451
0.105 0.444 0.050 0.010 0.456 0.003
0 0 0 0.5 0.1 6.4
0 0 0 0.1 0.3 0
-(g) N N B B R B B B + R B + R B + R Susceptible controls a b
384 412 411 404 441 374
± ± ± ± + ±
19.6 19.9 17.2^ 11.8b 9.7 17.3b
± ± ± ± + ±
18.8 15.9 12.9a 11.2a 15.9 16.0a
- Means in a row with no common superscript differ significantly (P < 0.05). Birds had received no medication (N), bacitracin methylene disalicylate (B), or roxarsone (R) as indicated. Susceptible controls were reared free of infection prior to challenge. 2 Weight gain from 0 to 6 d postinoculation. 3 Lesions present in the duodenum, mid-intestine, and ceca. 4 Each bird was inoculated with 300 times the normal dose of Coccivac-B®. x
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Susceptible birds, and birds that had received ROX followed by BMD, or BMD followed by BMD plus ROX (Treatments 3 and 4) gained significantly less weight than the unchallenged controls when challenged at 30 d (Table 2). Susceptible birds challenged at 51 d (Table 3) gained significantly less weight than the unchallenged susceptible controls but there were no significant differences in the weight gain of challenged birds from the various treatments and their unchallenged counterparts. Lesions were present in the intestines of susceptible birds challenged at 30 and 51 d but none were found in the unchallenged susceptible controls (Tables 2 and 3). Few or no lesions were found in challenged birds from the various treatments.
significant lesions were found in the intestines of birds examined at 27 d of age. Birds reared free of exposure to Eitneria species that were challenged with a high dose of the vaccine at 30 or 51 d gained significantly less weight than unchallenged birds and had substantial lesions in the intestines. This result indicates that the dose given was capable of causing pathogenic effects in susceptible controls. The weight gains of birds medicated with ROX followed by BMD (Treatment 3), and birds medicated with BMD followed by BMD plus ROX (Treatment 4) were significantly lower than those of the unchallenged birds by 30 d of age, although few or no lesions were found in their intestines. This result suggests that in birds given these treatments, immunity to the challenge infection had not fully developed by 30 d of age. By contrast, no significant differences in weight gains were evident for birds given the other treatments, suggesting that immunity had developed by 30 d of age. By 51 d, no significant differences in the weight gain of challenged and unchallenged birds were found and few or no lesions were found in their intestines, indicating that immunity had developed in birds given all treatments. The results differ from those of Mathis (1994), who found that broilers vaccinated at 3 d of age
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IMMUNITY IN BROILERS GIVEN A COCCIDIOSIS VACCINE TABLE 3. Weight gain ± SEM and lesions present in the intestines of broilers that had been challenged at 51 d of age with Eimeria species Weight gain2
Treatment1 Starter
Grower
Challenged
Lesion score3
Unchallenged
Probability
Challenged
Unchallenged
467 492 476 421 471 530
0.174 0.200 0.119 0.650 0.696 0.016
0 0 0 0 0 8.1
0 0 0 0 0 0
-(g) N N B B R B B B + R B + R B + R Susceptible controls
417 455 529 405 483 449
+ ± ± ± ± ±
26.8 14.2 20.2 25.3 19.7 24.6b
± ± ± ± ± ±
23.9 23.2 25.4 22.9 24.8 19.2*
ab
' Means in a row with no common superscript differ significantly (P < 0.05). iBirds had received no medication (N), bacitracin methylene disalicylate (B), or roxarsone (R) as indicated. Susceptible controls were reared free of infection prior to challenge. 2 Weight gain from 0 to 6 d postinoculation. 3 Lesions present in the duodenum, mid-intestine, and ceca. 4 Each bird was inoculated with 300 times the normal dose of Coccivac-B®.
9 Coccivac Technical Manual, Mallinckrodt Veterinary, Inc., Poultry Health Products Group, Millsboro, DE 19966-0537.
suggesting that the treatments given did not interfere with the development of immunity to E. tenella. The manufacturer of Coccivac B® does not recommend its use in broilers given ROX,9 but antibiotics such as BMD can be used with the vaccine. The results of this study suggest that Coccivac B® can be employed for the development of immunity to coccidiosis in broilers and that this use is not incompatible with the inclusion of ROX and BMD in the feed.
ACKNOWLEDGMENTS This w o r k w a s s u p p o r t e d b y a g r a n t from ALP H A R M A Inc., Fort Lee, NT 07024. The assistance of A. B. Hacker is gratefully a c k n o w l e d g e d .
REFERENCES Johnson, J., and W. M. Reid, 1970. Anticoccidial drugs: lesion scoring techniques in battery and floor pen experiments with chickens. Exp. Parasitol. 28:30-36. Kowalski, L. M., and W. M. Reid, 1972. Roxarsone: efficacy against Eimeria brunetti infections in chickens. Poultry Sci. 51:1586-1589. Kowalski, L. M., and W. M. Reid, 1975. Effects of roxarsone on pigmentation and coccidiosis in broilers. Poultry Sci. 54: 1544-1549. Mathis, G. F., 1994. The effects of feeding roxarsone to coccidiosis vaccinated broilers. Poultry Sci. 73(Suppl. 1):16. (Abstr.) McDougald, L. R., J. M. Gilbert, L. Fuller, A. Rotibi, M. Xie, and G. Zhu, 1992. How much does roxarsone contribute to coccidiosis control in broilers when used in combination with ionophores? Appl. Poult. Sci. 1:172-179. Morehouse, N. F., and O. J. Mayfield, 1946. The effects of some aryl arsonic acids on experimental coccidiosis infection in chickens. J. Parasitol. 32:20-24. Morehouse, N . F., a n d F. McKay, 1951. Action of 3-nitro-4-hydroxyphenylarsonic acid against Eimeria tenella in chickens. Iowa Acad. Sci. 58:507-516.
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with Coccivac B® and given ROX continuously in the diet were not fully immunized by 25 d when challenged with unspecified Eimeria species. The birds in this study had been placed on new litter in pens that had been cleaned thoroughly before use. It is likely, therefore, that the development of immunity resulted from exposure to oocysts produced as a result of vaccination rather than from any parasites that may have initially been present in the pens. There was no indication that the use of amprolium interfered with the development of immunity. Roxarsone has been used for many years for improving growth, feed efficiency, and pigmentation of poultry but very little information is available on the efficacy of the drug against Eimeria species. Hemorrhage and mortality due to E. tenella was eliminated by including ROX in the drinking water of chickens at a concentration of 0.0176 or 0.035% (Morehouse and Mayfield, 1946). Ryley and Betts (1973), however, consider that ROX has little activity against this species. Roxarsone also has some activity against E. brunetti and E. maxima (Kowalski and Reid, 1972, 1975; McDougald et al, 1992). Roxarsone had little anticoccidial efficacy against a field isolate of E. tenella when included in the feed at a concentration of 22.4 g/ton (McDougald et al, 1992), but an improvement in weight gain and a reduction in cecal lesions was apparent when ROX was given at 45.4 g / t o n (the maximum approved use level of the drug). Some isolates of E. tenella did not respond to ROX but the data were not reported. If ROX does have activity against Eimeria species, then it might be expected to interfere with the acquisition of immunity. This effect might be a problem with E. tenella, which is less immunogenic than species such as E. maxima (Rose, 1974). In this study, few lesions were found in the ceca of challenged birds,
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CHAPMAN AND FITZCOY
National Research Council, 1994. Nutrient Requirements of Poultry. 9th rev. ed. National Academy Press, Washington, DC. Rose, M. E., 1974. The early development of immunity to Eimeria maxima in comparison with that to Eimeria tenella.
Parasitology 68:35-45. Ryley, J. F., and M. J. Betts, 1973. Chemotherapy of chicken coccidiosis. Adv. Pharmacol. Chemother. 11:221-293. SAS Institute, 1988. SAS/STAT® User's Guide: 1988 Edition. SAS Institute Inc., Cary, NC.
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(Key words: broiler, immunity, coccidiosis vaccine, roxarsone, bacitracin methylene disalicylate) 1996 Poultry Science 75:1488-1492
INTRODUCTION Live coccidiosis vaccines have been available for many years for the control of coccidiosis in chickens. Although principally used for breeder stock (broiler breeders and birds reared for table egg production), in which the development of immunity to Eimeria species is desirable, vaccines have also occasionally been employed in broilers. The commercial vaccine used for broilers (Coccivac B®)3 contains strains of Eimeria isolated in the 1950s, before the introduction of most anticoccidial drugs. It is likely, therefore, that these strains (unlike many recent field isolates of Eimeria) are sensitive to currently used compounds. For this reason, it is important that birds given the vaccine should not be receiving anticoccidial medication. The feed additives roxarsone (ROX4) and bacitracin methylene disalicylate (BMD®4) are widely used in broiler production for increased rate of weight gain and improved feed efficiency.5 Although anticoccidial activity has not been reported for BMD, ROX may have some effect against Eimeria tenella, Eimeria brunetti,
Received for publication April 19, 1996. Accepted for publication August 27, 1996. iPublished with the approval of the Arkansas Agricultural Experiment Station Director. 2 To whom correspondence should be addressed. 3 Mallinckrodt Veterinary Inc., Millsboro, DE 19966-0537. 4 3-Nitro®, BMD®, ALPHARMA Inc., Fort Lee, NJ 07024. 5 1996 Feed Additive Compendium, The Miller Publishing Co., 12400 Whitewater Drive, Minnetonka, MN 55343. 6 Cobb 500, Cobb-Vantress Inc., Siloam Springs, AR 72764. 7 American Cyanamid Co., Animal Health and Nutrition Division, Wayne, NJ 07470.
and Eimeria maxima (Morehouse and McKay, 1951; Kowalski and Reid, 1972, 1975). It is possible, therefore, that ROX may interfere with the acquisition of immunity to Eimeria species. The present experiment was undertaken to investigate the effect of ROX and BMD, utilized separately or in combination, upon the development of immunity to Eimeria in chickens reared in floor pens and given a coccidiosis vaccine.
MATERIALS AND METHODS Birds and Housing Day-old male chicks of a commercial broiler strain 6 were obtained from a local hatchery and placed on new litter (rice hulls) in a clean floor pen facility. Chicks were randomly assigned to each of 25 pens (60 birds per pen) at a stocking density of 1 bird per 0.07 m 2 . Each pen contained two tubular hanging feeders and an automatic waterer. Thermostatically controlled gas brooders and ventilation fans were used to regulate temperature, and 23 h of light and 1 h of dark was provided each day. The chicks had been vaccinated against Newcastle, Infectious Bronchitis, and Marek's disease at the hatchery. Eighty chicks from the same hatch were taken to a clean animal room and reared in a Petersime brooder to serve as susceptible controls. They were given robenidine (30 g / ton) 7 in the feed as a precaution against accidental infection.
Feed All birds were fed a corn-soybean basal ration formulated to meet the nutritional requirements of the
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ABSTRACT No significant differences in the BW, feed intake, feed conversion, or mortality of broilers that had been vaccinated at 3 d of age with a live coccidiosis vaccine were observed irrespective of whether they had been given roxarsone, bacitracin methylene disalicylate, or both drugs in the feed. The weight gain of birds challenged with a high dose of the vaccine at 51 d was
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IMMUNITY IN BROILERS GIVEN A COCCIDIOSIS VACCINE broiler chicken (National Research Council, 1994). Starter, grower, and withdrawal feeds were provided from 0 to 21, 21 to 44, and 44 to 49 d, respectively. A uniform basal ration was mixed, and aliquots were used to prepare the test diets. Samples of feed were retained from each batch and assayed for the concentration of drugs. Assays were within limits of the intended concentrations. 5
Design
Performance
Data
Composite pen BW at 21, 44, and 49 d of age and total feed consumed for each age period were recorded. Birds that died were weighed, and their weights added to pen weights for calculation of feed conversion. Data were analyzed by one-way analysis of variance using the PROC ANOVA procedure of SAS® software (SAS Institute, 1988). Means were separated and compared using Duncan's multiple range test.
Challenge
A further 6 preselected birds were removed from each pen given the same treatment (total of 30 birds) at 28 and 49 d, placed in a clean pen on new litter, and given unmedicated feed. Two days later they were weighed, and 15 of the birds were inoculated orally with 300 times the normal dose of Coccivac-B® per bird. The other 15 birds were not infected and served as unchallenged controls. Six days later all birds were weighed once more, and the gain in weight was calculated. Means were compared by Student's t test using software of the SAS Institute (1988). Birds were killed by CO2 asphyxiation, and the intestines were examined for lesions due to coccidiosis.
Susceptible
RESULTS
Birds in all treatments were vaccinated at 3 d of age by mixing two 1,000-dose vials of Coccivac-B® in tap water so that 100 mL of the resulting suspension contained the appropriate dose of oocysts for 60 birds in each pen. The hanging feeders were then elevated, and 100 mL of oocyst suspension was mixed in 1,200 g of feed. The contaminated feed was placed on trays in the pens and was consumed in about 3 h. Ten days after vaccination, amproliumS (0.006%) was provided for 48 h in the drinking water.
Birds
Birds to be used for lesion scoring and in the challenge experiments were randomly selected when weighed at 21 d and tagged with a wing-band for identification. Five preselected birds were taken from each pen at 27 d
8
Controls
Birds that had been reared in isolation in brooders were transferred to clean pens at 22 and 27 d of age. From Day 27 and 48, respectively, they were given unmedicated feed (so that robenidine was not present in the feed for 3 d prior to challenge). Subsequently, these birds were subjected to the same procedures as the birds in the principal treatments. Thus, on Day 30 and 51, respectively, 30 birds from each pen were individually weighed and 15 birds challenged, the remainder serving as unchallenged controls. Six days later all birds were weighed, killed, and their intestines were examined for coccidial lesions.
Vaccination
Preselected
Experiments
Merck AgVet Division, Merck and Co., Inc. Rahway, NJ 07065-0912.
Performance Results for the performance of birds reared in floor pens are presented in Table 1. There were no significant differences among treatments in BW, feed intake, or feed conversion for any age period.
Mortality Mean percentage mortality < SEM was 3.6 < 1.3,10.5 < 2.1, and 13.4 < 2.8, by 21,44, and 49 d of age respectively. There were no significant differences in mortality among treatments (data not given). Lesions due to Eimeria species were not seen in any of the birds that died.
Lesions in Preselected
Birds
No lesions were found in the duodenum or midintestine of birds examined at 27 d of age. Very few lesions were found in the ceca (total mean lesion score < 0.1).
Downloaded from http://ps.oxfordjournals.org/ at University of Georgia on June 5, 2015
A randomized block design was employed in which birds were given either no medication or ROX and BMD utilized separately or in combination as might be employed in commercial practice. The treatments were: 1) No medication, 2) BMD (50.0 g/ton) in the starter ration and BMD (25.0 g/ton) in the grower feed, 3) ROX (45.4 g / ton) in the starter and BMD (50.0 g/ton) in the grower, 4) BMD (50.0 g/ton) in the starter and BMD (25.0 g/ton) plus ROX (45.4 g/ton) in the grower, and 5) BMD (50.0 g/ton) plus ROX (45.4 g/ton) in the starter and BMD (25.0 g/ton) plus ROX (45.4 g/ton) in the grower feed. Birds were given no drugs (Treatment 1) or BMD (25.0 g/ton) in the withdrawal ration (Treatments 2, 3, 4, and 5).
necropsied, and the duodenum, mid-intestine, and ceca were examined for lesions due to coccidiosis (Johnson and Reid, 1970). Lesion scores for each region of the intestine were combined.
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CHAPMAN AND FITZCOY
TABLE 1. Effect of roxarsone and bacitracin methylene disalicylate upon the performance of broilers given a coccidiosis vaccine Treatment 1 Starter
Weight gain 0 to 21 d
Grower
0 to 44 d
Feed intake per bird 0 to 49 d
0 to 21 d
0 to 44 d
Feed conversion
0 to 49 d
0 to 21 d
0 to 44 d
0 to 49 d
1.380 1.432 1.443 1.429 1.443 0.016 0.136
l~.~\ yb-y 1.789 1.797 1.761 1.791 1.797 0.033 0.964
1.877 1.894 1.857 1.884 1.888 0.030 0.964
(g) N B R B B + R SEM Probability
N B B B + R B + R
732 730 731 728 742 8 0.879
2,484 2,491 2,519 2,479 2,497 29 0.912
2,842 2,799 2,851 2,825 2,814 38 0.893
1,009 1,045 1,055 1,041 1,070 14 0.130
4,443 4,476 4,434 4,430 4,485 67 0.988
5,333 5,300 5,292 5,313 5,312 69 0.986
!B = bacitracin methylene disalicylate; R = roxarsone; N = no medication were given in either the Starter or Grower feeds as indicated.
Challenged Birds
DISCUSSION No significant differences in BW, feed intake, or feed conversion were observed irrespective of whether vaccinated birds were given ROX, BMD, BMD plus ROX, or no medication in the starter and grower rations. Mortality was similar in all treatments, and coccidiosis was not observed as a cause of death in the trial. No
TABLE 2. Weight gain ± SEM and lesions present in the intestine, of broilers that had been challenged at 30 d of age with Eitneria species Treatment 1 Starter
Grower
Weight gain 2 Challenged
Lesion score 3
Unchallenged
Probability
Challenged
Unchallenged
429 432 455 449 427 451
0.105 0.444 0.050 0.010 0.456 0.003
0 0 0 0.5 0.1 6.4
0 0 0 0.1 0.3 0
-(g) N N B B R B B B + R B + R B + R Susceptible controls a b
384 412 411 404 441 374
± ± ± ± + ±
19.6 19.9 17.2^ 11.8b 9.7 17.3b
± ± ± ± + ±
18.8 15.9 12.9a 11.2a 15.9 16.0a
- Means in a row with no common superscript differ significantly (P < 0.05). Birds had received no medication (N), bacitracin methylene disalicylate (B), or roxarsone (R) as indicated. Susceptible controls were reared free of infection prior to challenge. 2 Weight gain from 0 to 6 d postinoculation. 3 Lesions present in the duodenum, mid-intestine, and ceca. 4 Each bird was inoculated with 300 times the normal dose of Coccivac-B®. x
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Susceptible birds, and birds that had received ROX followed by BMD, or BMD followed by BMD plus ROX (Treatments 3 and 4) gained significantly less weight than the unchallenged controls when challenged at 30 d (Table 2). Susceptible birds challenged at 51 d (Table 3) gained significantly less weight than the unchallenged susceptible controls but there were no significant differences in the weight gain of challenged birds from the various treatments and their unchallenged counterparts. Lesions were present in the intestines of susceptible birds challenged at 30 and 51 d but none were found in the unchallenged susceptible controls (Tables 2 and 3). Few or no lesions were found in challenged birds from the various treatments.
significant lesions were found in the intestines of birds examined at 27 d of age. Birds reared free of exposure to Eitneria species that were challenged with a high dose of the vaccine at 30 or 51 d gained significantly less weight than unchallenged birds and had substantial lesions in the intestines. This result indicates that the dose given was capable of causing pathogenic effects in susceptible controls. The weight gains of birds medicated with ROX followed by BMD (Treatment 3), and birds medicated with BMD followed by BMD plus ROX (Treatment 4) were significantly lower than those of the unchallenged birds by 30 d of age, although few or no lesions were found in their intestines. This result suggests that in birds given these treatments, immunity to the challenge infection had not fully developed by 30 d of age. By contrast, no significant differences in weight gains were evident for birds given the other treatments, suggesting that immunity had developed by 30 d of age. By 51 d, no significant differences in the weight gain of challenged and unchallenged birds were found and few or no lesions were found in their intestines, indicating that immunity had developed in birds given all treatments. The results differ from those of Mathis (1994), who found that broilers vaccinated at 3 d of age
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IMMUNITY IN BROILERS GIVEN A COCCIDIOSIS VACCINE TABLE 3. Weight gain ± SEM and lesions present in the intestines of broilers that had been challenged at 51 d of age with Eimeria species Weight gain2
Treatment1 Starter
Grower
Challenged
Lesion score3
Unchallenged
Probability
Challenged
Unchallenged
467 492 476 421 471 530
0.174 0.200 0.119 0.650 0.696 0.016
0 0 0 0 0 8.1
0 0 0 0 0 0
-(g) N N B B R B B B + R B + R B + R Susceptible controls
417 455 529 405 483 449
+ ± ± ± ± ±
26.8 14.2 20.2 25.3 19.7 24.6b
± ± ± ± ± ±
23.9 23.2 25.4 22.9 24.8 19.2*
ab
' Means in a row with no common superscript differ significantly (P < 0.05). iBirds had received no medication (N), bacitracin methylene disalicylate (B), or roxarsone (R) as indicated. Susceptible controls were reared free of infection prior to challenge. 2 Weight gain from 0 to 6 d postinoculation. 3 Lesions present in the duodenum, mid-intestine, and ceca. 4 Each bird was inoculated with 300 times the normal dose of Coccivac-B®.
9 Coccivac Technical Manual, Mallinckrodt Veterinary, Inc., Poultry Health Products Group, Millsboro, DE 19966-0537.
suggesting that the treatments given did not interfere with the development of immunity to E. tenella. The manufacturer of Coccivac B® does not recommend its use in broilers given ROX,9 but antibiotics such as BMD can be used with the vaccine. The results of this study suggest that Coccivac B® can be employed for the development of immunity to coccidiosis in broilers and that this use is not incompatible with the inclusion of ROX and BMD in the feed.
ACKNOWLEDGMENTS This w o r k w a s s u p p o r t e d b y a g r a n t from ALP H A R M A Inc., Fort Lee, NT 07024. The assistance of A. B. Hacker is gratefully a c k n o w l e d g e d .
REFERENCES Johnson, J., and W. M. Reid, 1970. Anticoccidial drugs: lesion scoring techniques in battery and floor pen experiments with chickens. Exp. Parasitol. 28:30-36. Kowalski, L. M., and W. M. Reid, 1972. Roxarsone: efficacy against Eimeria brunetti infections in chickens. Poultry Sci. 51:1586-1589. Kowalski, L. M., and W. M. Reid, 1975. Effects of roxarsone on pigmentation and coccidiosis in broilers. Poultry Sci. 54: 1544-1549. Mathis, G. F., 1994. The effects of feeding roxarsone to coccidiosis vaccinated broilers. Poultry Sci. 73(Suppl. 1):16. (Abstr.) McDougald, L. R., J. M. Gilbert, L. Fuller, A. Rotibi, M. Xie, and G. Zhu, 1992. How much does roxarsone contribute to coccidiosis control in broilers when used in combination with ionophores? Appl. Poult. Sci. 1:172-179. Morehouse, N. F., and O. J. Mayfield, 1946. The effects of some aryl arsonic acids on experimental coccidiosis infection in chickens. J. Parasitol. 32:20-24. Morehouse, N . F., a n d F. McKay, 1951. Action of 3-nitro-4-hydroxyphenylarsonic acid against Eimeria tenella in chickens. Iowa Acad. Sci. 58:507-516.
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with Coccivac B® and given ROX continuously in the diet were not fully immunized by 25 d when challenged with unspecified Eimeria species. The birds in this study had been placed on new litter in pens that had been cleaned thoroughly before use. It is likely, therefore, that the development of immunity resulted from exposure to oocysts produced as a result of vaccination rather than from any parasites that may have initially been present in the pens. There was no indication that the use of amprolium interfered with the development of immunity. Roxarsone has been used for many years for improving growth, feed efficiency, and pigmentation of poultry but very little information is available on the efficacy of the drug against Eimeria species. Hemorrhage and mortality due to E. tenella was eliminated by including ROX in the drinking water of chickens at a concentration of 0.0176 or 0.035% (Morehouse and Mayfield, 1946). Ryley and Betts (1973), however, consider that ROX has little activity against this species. Roxarsone also has some activity against E. brunetti and E. maxima (Kowalski and Reid, 1972, 1975; McDougald et al, 1992). Roxarsone had little anticoccidial efficacy against a field isolate of E. tenella when included in the feed at a concentration of 22.4 g/ton (McDougald et al, 1992), but an improvement in weight gain and a reduction in cecal lesions was apparent when ROX was given at 45.4 g / t o n (the maximum approved use level of the drug). Some isolates of E. tenella did not respond to ROX but the data were not reported. If ROX does have activity against Eimeria species, then it might be expected to interfere with the acquisition of immunity. This effect might be a problem with E. tenella, which is less immunogenic than species such as E. maxima (Rose, 1974). In this study, few lesions were found in the ceca of challenged birds,
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National Research Council, 1994. Nutrient Requirements of Poultry. 9th rev. ed. National Academy Press, Washington, DC. Rose, M. E., 1974. The early development of immunity to Eimeria maxima in comparison with that to Eimeria tenella.
Parasitology 68:35-45. Ryley, J. F., and M. J. Betts, 1973. Chemotherapy of chicken coccidiosis. Adv. Pharmacol. Chemother. 11:221-293. SAS Institute, 1988. SAS/STAT® User's Guide: 1988 Edition. SAS Institute Inc., Cary, NC.
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