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Virginiamycin Effects on Controlling Necrotic Enteritis Infection in Chickens1
Virginiamycin Effects on Controlling Necrotic Enteritis Infection in Chickens1 B. A. GEORGE, C. L. QUARLES, and D. J. FAGERBERG Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523 (Received for publication July 13, 1981)
1982 Poultry Science 6 1 : 4 4 7 - 4 5 0
INTRODUCTION
MATERIALS AND METHODS
Necrotic enteritis, first reported by Parish (1961), continues to be an important disease of broiler chickens. It is well established that Clostridium perfringens causes the disease (AlSheikhly and Al-Saieg, 1980). Necrotic enteritis infections have been successfully reproduced by raising birds in houses where necrotic enteritis outbreaks have previously occurred (Wicker et al., 1977); by administration of feed infected with C. perfringens (Prescott, 1979); and by intraduodenal administration of broth cultures or toxins of C. perfringens (Al-Sheikhly and Truscott, 1977a,b). Virginiamycin is an antibiotic produced by a mutant of Streptomyces virginiae and is primarily active against gram-positive bacteria. Presently, virginiamycin may be fed to swine for increased weight gains, improved feed efficiency, and as an aid in controlling dysentery (Feed Additive Compendium, 1980). The purpose of this study was to evaluate the effects of virginiamycin in controlling a necrotic enteritis infection in chickens produced artificially by oral administration of broth cultures of C. perfringens,
Experimental Design Two replicate trials were conducted. Each trial consisted of six treatments — two controls (one infected and one noninfected) and five infected, medicated treatments. Each treatment was replicated four times using ten chicks per replication. An outline of the experimental design is shown in Table 1. Chicks Day-old male broiler chicks (Indian River) were reared in start-grow cages located in an environmentally controlled building. Birds were placed on respective medicated or control feed at day 1. Feed and water were supplied ad libitum. Feed Basal feed ration contained 26% fish meal. Medicated rations incorporated virginiamycin into the basal ration at levels of 5, 10, 15, 20, and 40 g/ton. Culture Preparation and
1 Published with the approval of the Colorado State University Experiment Station and published as Scientific Series Paper No. 2664.
Administration
Clostridium perfringens, obtained from a recent field outbreak of necrotic enteritis, was supplied by Smith Kline Animal Health Products (Philadelphia, PA). The culture was incubated aerobically at 35 to 37 C in freshly pre-
447
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
ABSTRACT Duplicate trials were conducted with male broiler chickens to evaluate virginiamycin as treatment against experimentally induced necrotic enteritis infection. Each trial consisted of seven treatments, each replicated four times, with 10 birds per replicate. Two treatments were fed control ration (noninfected control and infected control) and the five remaining treatments were fed virginiamycin at 5, 10, 15, 20, or 40 g/ton. Birds were orally dosed with 10 ml of Clostridium perfnngens culture at 14 days of age. At 5 weeks of age, surviving birds were killed and necropsied to obtain lesion scores. Birds fed virginiamycin had significantly less mortality and lower intestinal lesion scores than nonmedicated birds when experimentally infected with necrotic enteritis. (Key words: necrotic enteritis, virginiamycin, chickens)
448
GEORGE ET AL. TABLE 1. Experimental design used to evaluate effect of virginiamycin for the treatment of necrotic enteritis infection in chickens
Route of medication
Treatment
Feed Feed Feed Feed Feed
Total
pared Fluid Thioglycollate Medium (Baltimore Biological Laboratories, CockeysviUe, MD) for 15 hr. Birds were orally dosed at 14 days of age, using a 10 cc syringe with 6 cm surgical tubing attached. Ten milliliters of culture were dispensed directly into the crop of each bird three times per day (0800, 1200, 1700 hr) for 5 consecutive days. Prior to first dosing, feed was removed 20 hr in advance and then removed 1 hr before dosing at all other times. Evaluation Criteria Mortality. Mortality was observed and recorded twice daily. Necropsies were performed on all dead birds and intestinal lesions scored. In all groups, percent mortality was based on
Chicks/ pen
Total chicks/ treatment
4 4 4 4 4 4 4
10 10 10 10 10 10 10
40 40 40 40 40 40 40
28
70
280
number of live birds at 14 days of age. Mortality prior to day 14 was not a result of necrotic enteritis infection. Lesions. At 35 days of age, all surviving birds were killed by cervical dislocation and necropsied. Lesion scores were assigned values as follows: 0 = normal, no lesions; 1 = small lesions covering 2.5 cm or less of intestine; 2 = lesions covering greater than 2.5 cm 2 of intestine; 3 = severe lesions throughout the intestine. Feed Efficiency and Body Weights. Throughout the trial all feed was weighed into each pen. At trial termination total feed consumption was recorded and surviving birds were weighed on a pen basis to determine weight gain and feed efficiency. Feed consumption was adjusted for birds dying during the study.
TABLE 2. Body weights, feed efficiency, mortality, and lesion scores for Trial 1 testing the effects of virginiamycin for the treatment of necrotic enteritis infection in chickens
Treatment
Virginiamycin (g/t)
Infected
Average body weight
Feed efficiency
Mortality (%)
Lesion scores
A B C D E F G
0 5 10 15 20 40 0
Yes Yes Yes Yes Yes Yes No
858* 1051b 1061b 1053b 1083b 1082b 1088b
1.91a 1.48b 1.49 b 1.58b 1.46 b 1.49 b 1.48b
37.5a 13.5b 6.3b 15.0b 5.0b 7.5b 5.0b
2.1*
Ie * Values of the same data item with like superscripts are not significantly different (P<.01).
1 lb 53cd 4de 5d 03e
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
A—infected, n o n m e d i c a t e d B—infected, 5 g/t C - i n f e c t e d , 10 g/t D - i n f e c t e d , 15 g/t E - i n f e c t e d , 20 g/t F—infected, 4 0 g/t G—noninfected, n o n m e d i c a t e d
Pens/ treatment
VIRGINIAMYCIN FOR TREATMENT OF NECROTIC ENTERITIS
449
TABLE 3. Body weights, feed efficiency, mortality, and lesion scores for Trial 2 testing the effects of virginiamycin for the treatment of necrotic enteritis infection in chickens Treatment
Virginiamycin (g/t)
Infected
Average body weight
Feed efficiency
Mortality (%)
Lesion scores
A B C D E F G
0 5 10 15 20 40 0
Yes Yes Yes Yes Yes Yes No
1029a 1306b 1401c 1365bc 1408C 1380C 1396C
2.07a 1.63b 1.48 c 1.51bc 1.55bc 1.50C 1.51bc
37.5a 7.5b 5.0b 2.5b 2.5b 2.5b 7.3b
2.0a 1.3b .
Statistical
Analysis
Analysis of variance was carried out on mortality, lesion scores, body weights, and feed efficiency (Snedecor and Cochran, 1967). RESULTS AND DISCUSSION
Mortality For the infected, nonmedicated treatment group percent mortality in both trials was 37.5%. This was significantly (P<.01) greater than in any of the other treatments (Tables 2 and 3). There were no significant differences between any of the medicated treatments and the noninfected, nonmedicated control group. Necropsy of dead birds in noninfected control group revealed mortality was not due to necrotic enteritis infection. Lesion Scores
ACKNOWLEDGMENT
In both trials, the nonmedicated, noninfected group birds had a significantly lower (P< .01) intestinal lesion score than any of the other treatments except for Treatment E (20 g/ton) in Trial 1. The nonmedicated, infected group had a significantly higher intestinal lesion score than any other group in both trials. Among the medicated treatments in Trial 1, Treatments E and F (20 and 40 g/ton, respectively) had a significantly lower lesion score than either Treatment B and C (5 and 10 g/ton, respectively); however, in Trial 2, Treatments E and F were significantly different from only Treatment B. Weight Gain and Feed
nificantly (P<.01) reduced in the nonmedicated, infected group compared to all other treatments in both trials. There were no differences among treatments in Trial 1. In Trial 2, birds of Treatment B (5 g/ton) had significantly (P<.01) less body weight gain than any of the other treatments except Treatment D (15 g/ton). Feed efficiency of Treatment B birds was significantly (P<.01) reduced when compared to Treatments C and F (10 and 40 g/ton, respectively). Overall, both trials yielded similar results, indicating that virginiamycin, whether fed at 5, 10, 15, 20, or 40 g/ton, is effective in controlling a severe necrotic enteritis infection. In addition, no detrimental effects on body weights or feed efficiency resulted from the infection when virginiamycin was included in the diet.
Efficiency
Body weights and feed efficiency were sig-
We gratefully acknowledge the support of Smith Kline Animal Health Products. REFERENCES Al-Sheikhly, F., and A. Al-Saieg, 1980. Role of coccidia in the occurrence of necrotic enteritis of chickens. Avian Dis. 24:324—333. Al-Sheikhly, F., and R. B. Truscott, 1977a. The pathology of necrotic enteritis of chickens following infusion of broth cultures of Clostridium perfringens into the duodenum. Avian Dis. 21: 230-240. Al-Sheikhly, F., and R. B. Truscott, 1977b. The pathology of necrotic enteritis of chickens following infusion of crude toxins of Clostridium perfringens into the duodenum. Avian Dis. 21: 241-255. Feed Additive Compendium. 1980. Miller Publ. Co., Minneapolis, MN.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
a,b,c,d Values of the same data item with like superscripts are not significantly different (P<.01).
450
GEORGE ET AL.
Parish, W. E., 1961. Necrotic enteritis in the fowl. I. Histopathology of the disease and isolation of a strain of Clostridium welchii. J. Comp. Pathol. 71:377-393. Prescott, J. F., 1979. The prevention of experimentally induced necrotic enteritis in chickens by avoparcin. Avian Dis. 24:1072-1074.
Snedecor, G. W., and W. G. Cochran, 1967. Statistical Methods. 6th ed. Iowa State Univ. Press, Ames, IA. Wicker, D. L., W. N. Isgrigg, and J. H. Trammell, 1977. The control and prevention of necrotic enteritis in broilers with zinc bacitracin. Poultry Sci. 56: 1229-1231.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
1982 Poultry Science 6 1 : 4 4 7 - 4 5 0
INTRODUCTION
MATERIALS AND METHODS
Necrotic enteritis, first reported by Parish (1961), continues to be an important disease of broiler chickens. It is well established that Clostridium perfringens causes the disease (AlSheikhly and Al-Saieg, 1980). Necrotic enteritis infections have been successfully reproduced by raising birds in houses where necrotic enteritis outbreaks have previously occurred (Wicker et al., 1977); by administration of feed infected with C. perfringens (Prescott, 1979); and by intraduodenal administration of broth cultures or toxins of C. perfringens (Al-Sheikhly and Truscott, 1977a,b). Virginiamycin is an antibiotic produced by a mutant of Streptomyces virginiae and is primarily active against gram-positive bacteria. Presently, virginiamycin may be fed to swine for increased weight gains, improved feed efficiency, and as an aid in controlling dysentery (Feed Additive Compendium, 1980). The purpose of this study was to evaluate the effects of virginiamycin in controlling a necrotic enteritis infection in chickens produced artificially by oral administration of broth cultures of C. perfringens,
Experimental Design Two replicate trials were conducted. Each trial consisted of six treatments — two controls (one infected and one noninfected) and five infected, medicated treatments. Each treatment was replicated four times using ten chicks per replication. An outline of the experimental design is shown in Table 1. Chicks Day-old male broiler chicks (Indian River) were reared in start-grow cages located in an environmentally controlled building. Birds were placed on respective medicated or control feed at day 1. Feed and water were supplied ad libitum. Feed Basal feed ration contained 26% fish meal. Medicated rations incorporated virginiamycin into the basal ration at levels of 5, 10, 15, 20, and 40 g/ton. Culture Preparation and
1 Published with the approval of the Colorado State University Experiment Station and published as Scientific Series Paper No. 2664.
Administration
Clostridium perfringens, obtained from a recent field outbreak of necrotic enteritis, was supplied by Smith Kline Animal Health Products (Philadelphia, PA). The culture was incubated aerobically at 35 to 37 C in freshly pre-
447
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
ABSTRACT Duplicate trials were conducted with male broiler chickens to evaluate virginiamycin as treatment against experimentally induced necrotic enteritis infection. Each trial consisted of seven treatments, each replicated four times, with 10 birds per replicate. Two treatments were fed control ration (noninfected control and infected control) and the five remaining treatments were fed virginiamycin at 5, 10, 15, 20, or 40 g/ton. Birds were orally dosed with 10 ml of Clostridium perfnngens culture at 14 days of age. At 5 weeks of age, surviving birds were killed and necropsied to obtain lesion scores. Birds fed virginiamycin had significantly less mortality and lower intestinal lesion scores than nonmedicated birds when experimentally infected with necrotic enteritis. (Key words: necrotic enteritis, virginiamycin, chickens)
448
GEORGE ET AL. TABLE 1. Experimental design used to evaluate effect of virginiamycin for the treatment of necrotic enteritis infection in chickens
Route of medication
Treatment
Feed Feed Feed Feed Feed
Total
pared Fluid Thioglycollate Medium (Baltimore Biological Laboratories, CockeysviUe, MD) for 15 hr. Birds were orally dosed at 14 days of age, using a 10 cc syringe with 6 cm surgical tubing attached. Ten milliliters of culture were dispensed directly into the crop of each bird three times per day (0800, 1200, 1700 hr) for 5 consecutive days. Prior to first dosing, feed was removed 20 hr in advance and then removed 1 hr before dosing at all other times. Evaluation Criteria Mortality. Mortality was observed and recorded twice daily. Necropsies were performed on all dead birds and intestinal lesions scored. In all groups, percent mortality was based on
Chicks/ pen
Total chicks/ treatment
4 4 4 4 4 4 4
10 10 10 10 10 10 10
40 40 40 40 40 40 40
28
70
280
number of live birds at 14 days of age. Mortality prior to day 14 was not a result of necrotic enteritis infection. Lesions. At 35 days of age, all surviving birds were killed by cervical dislocation and necropsied. Lesion scores were assigned values as follows: 0 = normal, no lesions; 1 = small lesions covering 2.5 cm or less of intestine; 2 = lesions covering greater than 2.5 cm 2 of intestine; 3 = severe lesions throughout the intestine. Feed Efficiency and Body Weights. Throughout the trial all feed was weighed into each pen. At trial termination total feed consumption was recorded and surviving birds were weighed on a pen basis to determine weight gain and feed efficiency. Feed consumption was adjusted for birds dying during the study.
TABLE 2. Body weights, feed efficiency, mortality, and lesion scores for Trial 1 testing the effects of virginiamycin for the treatment of necrotic enteritis infection in chickens
Treatment
Virginiamycin (g/t)
Infected
Average body weight
Feed efficiency
Mortality (%)
Lesion scores
A B C D E F G
0 5 10 15 20 40 0
Yes Yes Yes Yes Yes Yes No
858* 1051b 1061b 1053b 1083b 1082b 1088b
1.91a 1.48b 1.49 b 1.58b 1.46 b 1.49 b 1.48b
37.5a 13.5b 6.3b 15.0b 5.0b 7.5b 5.0b
2.1*
Ie * Values of the same data item with like superscripts are not significantly different (P<.01).
1 lb 53cd 4de 5d 03e
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
A—infected, n o n m e d i c a t e d B—infected, 5 g/t C - i n f e c t e d , 10 g/t D - i n f e c t e d , 15 g/t E - i n f e c t e d , 20 g/t F—infected, 4 0 g/t G—noninfected, n o n m e d i c a t e d
Pens/ treatment
VIRGINIAMYCIN FOR TREATMENT OF NECROTIC ENTERITIS
449
TABLE 3. Body weights, feed efficiency, mortality, and lesion scores for Trial 2 testing the effects of virginiamycin for the treatment of necrotic enteritis infection in chickens Treatment
Virginiamycin (g/t)
Infected
Average body weight
Feed efficiency
Mortality (%)
Lesion scores
A B C D E F G
0 5 10 15 20 40 0
Yes Yes Yes Yes Yes Yes No
1029a 1306b 1401c 1365bc 1408C 1380C 1396C
2.07a 1.63b 1.48 c 1.51bc 1.55bc 1.50C 1.51bc
37.5a 7.5b 5.0b 2.5b 2.5b 2.5b 7.3b
2.0a 1.3b .
Statistical
Analysis
Analysis of variance was carried out on mortality, lesion scores, body weights, and feed efficiency (Snedecor and Cochran, 1967). RESULTS AND DISCUSSION
Mortality For the infected, nonmedicated treatment group percent mortality in both trials was 37.5%. This was significantly (P<.01) greater than in any of the other treatments (Tables 2 and 3). There were no significant differences between any of the medicated treatments and the noninfected, nonmedicated control group. Necropsy of dead birds in noninfected control group revealed mortality was not due to necrotic enteritis infection. Lesion Scores
ACKNOWLEDGMENT
In both trials, the nonmedicated, noninfected group birds had a significantly lower (P< .01) intestinal lesion score than any of the other treatments except for Treatment E (20 g/ton) in Trial 1. The nonmedicated, infected group had a significantly higher intestinal lesion score than any other group in both trials. Among the medicated treatments in Trial 1, Treatments E and F (20 and 40 g/ton, respectively) had a significantly lower lesion score than either Treatment B and C (5 and 10 g/ton, respectively); however, in Trial 2, Treatments E and F were significantly different from only Treatment B. Weight Gain and Feed
nificantly (P<.01) reduced in the nonmedicated, infected group compared to all other treatments in both trials. There were no differences among treatments in Trial 1. In Trial 2, birds of Treatment B (5 g/ton) had significantly (P<.01) less body weight gain than any of the other treatments except Treatment D (15 g/ton). Feed efficiency of Treatment B birds was significantly (P<.01) reduced when compared to Treatments C and F (10 and 40 g/ton, respectively). Overall, both trials yielded similar results, indicating that virginiamycin, whether fed at 5, 10, 15, 20, or 40 g/ton, is effective in controlling a severe necrotic enteritis infection. In addition, no detrimental effects on body weights or feed efficiency resulted from the infection when virginiamycin was included in the diet.
Efficiency
Body weights and feed efficiency were sig-
We gratefully acknowledge the support of Smith Kline Animal Health Products. REFERENCES Al-Sheikhly, F., and A. Al-Saieg, 1980. Role of coccidia in the occurrence of necrotic enteritis of chickens. Avian Dis. 24:324—333. Al-Sheikhly, F., and R. B. Truscott, 1977a. The pathology of necrotic enteritis of chickens following infusion of broth cultures of Clostridium perfringens into the duodenum. Avian Dis. 21: 230-240. Al-Sheikhly, F., and R. B. Truscott, 1977b. The pathology of necrotic enteritis of chickens following infusion of crude toxins of Clostridium perfringens into the duodenum. Avian Dis. 21: 241-255. Feed Additive Compendium. 1980. Miller Publ. Co., Minneapolis, MN.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015
a,b,c,d Values of the same data item with like superscripts are not significantly different (P<.01).
450
GEORGE ET AL.
Parish, W. E., 1961. Necrotic enteritis in the fowl. I. Histopathology of the disease and isolation of a strain of Clostridium welchii. J. Comp. Pathol. 71:377-393. Prescott, J. F., 1979. The prevention of experimentally induced necrotic enteritis in chickens by avoparcin. Avian Dis. 24:1072-1074.
Snedecor, G. W., and W. G. Cochran, 1967. Statistical Methods. 6th ed. Iowa State Univ. Press, Ames, IA. Wicker, D. L., W. N. Isgrigg, and J. H. Trammell, 1977. The control and prevention of necrotic enteritis in broilers with zinc bacitracin. Poultry Sci. 56: 1229-1231.
Downloaded from http://ps.oxfordjournals.org/ at D H Hill Library - Acquis S on April 28, 2015