660
E.
BROTSKY
Egg Prod. Conf., Cornell Univ., Ithaca, N.Y., 23-26. Mountney, G. J., and F. C. Arganosa, 1963. The effect of phosphates on moisture absorption, retention and cooking losses of broiler carcasses. Poultry Sci. 42: 384-388. Sato, K., and G. R. Hegarty, 1971. Warmed-over flavor in cooked meats. J. Food Sci. 36: 1098-1102. Stadelman, W. J., R. B. Harrington and K. K. Hale, 1971. Improving turkey meat quality by carcass
injection. Poultry Sci. 50: 898-900. Thomson, J. E., 1964. Effect of polyphosphates on oxidative deterioration of commercially cooked fryer chickens. Food Technol. 18: 147-148. Turner, E. W., W. D. Paynter, F. J. Montie, M. W. Bessert, G. M. Struck and F. C. Olson, 1954. Use of the 2-thiobarbituric acid reagent to measure rancidity in frozen pork. Food Technol. 8: 326-329.
O.
O H E AND A.
ARAKAWA
Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., 2-1-6, Kashima-cho, Osaka 532, Japan
Yodogawa-ku,
(Received for publication June 30, 1975)
ABSTRACT Two experiments were performed to study the effect of dietary antibiotics on percent daily weight change, mortality and gross cecal pathology in chickens during the critical phase of Eimeria tenella infection. In the first experiment, chickens were continuously fed ration containing thiopeptin, 2 mg./kg.; bacitracin, 20 mg./kg.; penicillin, 12 mg./kg.; or chlortetracycline, 22 mg./kg. One day after antibiotic feed was given, each bird received an oral inoculation of 30,000 sporulated oocysts. In the second experiment, chickens were consecutively fed ration containing amprolium plus ethopabate, 125 plus 8 mg./kg., and a combination of the coccidiostat and one of 4 antibiotics; thiopeptin, bacitracin, penicillin, or chlortetracycline. One day after medicated feed was given, birds were each given an oral inoculation of 30,000 amprolium plus ethopabate-resistant E. tenella oocysts. The experiments were terminated 7 days after coccidia exposure. In both experiments, E. tenella infection resulted in depression in all birds of infected groups. Average percent weight change of infected birds was significantly lower than that of uninfected unmedicated control between 4 and 5 days after infection. Significantly greater number of birds died of cecal coccidiosis in group fed dietary bacitracin than that of other infected groups. Dietary antibiotics did not reduce gross cecal lesions. POULTRY SCIENCE 55: 660-665, 1976
INTRODUCTION
V
I S C O and Burns (1972) reported that the p e r c e n t daily weight change is an important p a r a m e t e r to assess the severity of cecal coccidiosis caused b y Eimeria tenella. T h e y found that the weight change of infected conventionals w a s lower than that of infected bacteria-free chicks between days 4 and 5, 5 and 6, and 6 and 7 after infection. Mortality rate and cecal gross lesions at necropsy were greater in conventional infected chickens than those found in germ-free chickens (Visco and Burns, 1972; Radhakrishnan and Bradley, 1973; J o h n s o n et al., 1973).
Previous work d e m o n s t r a t e d that w h e n chickens were infected with E. tenella continuous use of antibiotic; thiopeptin, zinc bacitracin, penicillin, o r c h l o r t e t r a c y c l i n e ; via the feed for 3 w e e k s p r o m p t e d recovery from depressed b o d y weight as c o m p a r e d with chickens fed basal ration, and that w h e n birds were infected with amprolium plus ethopabate-resistant strain of E. tenella a combination of antibiotic and amprolium plus ethopabate in the feed for 3 w e e k s resulted in higher weight attained than amprolium plus ethopabate alone (Ohe and A r a k a w a , 1975). In the present experiment, emphasis was placed on the effect of these feed additive antibiotics
Downloaded from http://ps.oxfordjournals.org/ at UCSF Library on April 11, 2015
Effect of Dietary Antibiotics on Chickens Infected with Eimeria tenella
ANTIBIOTICS AND EIMERIA TENELLA
on percent daily weight change, mortality and gross cecal pathology in chickens during the critical phase of cecal coccidiosis. Two experiments were performed: E. tenella infection in the presence of antibiotics in the feed and amprolium plus ethopabate-resistant E. tenella infection in the presence of antibiotics and the coccidiostat. MATERIALS AND METHODS
Diet. The composition of the basal ration is reported previously (Arakawa and Ohe, 1975). Medicated diet was prepared by mixing the basal ration with a measured amount of commercial premix. Levels of antibiotic and coccidiostat in feed (mg./kg.) were: thiopeptin,' 2; zinc bacitracin, 2 20; procaine penicillin G,3 12; chlortetracycline hydrochloride, 4 22; and amprolium plus ethopabate, 5 125 plus 8. Experiment 1. A total of 180 chickens, 15 days old, were divided into 6 groups of 3 replicates each with 10 chickens per replicate. The groups consisted of those infected fed a ration containing either thiopeptin, bacitracin, penicillin, or chlortetracycline. The two groups were an infected, unmedicated group and an uninfected, unmedicated group. The respective rations and water were given continuously beginning one day prior to coccidia exposure until 7 days after infection. Fresh oocyst cultures were prepared routinely from 1. 2. 3. 4.
Fujisawa Pharmaceutical Co., Ltd., Osaka. Nippon Kayaku Co., Ltd., Osaka. Taito Pfizer Co., Ltd., Tokyo. Takeda Chemical Industries, Osaka.
5. Marupi-Merck, Sharp and Dohme, Osaka.
donor birds 7 to 8 days after infection. Birds in infected groups each received an oral inoculation of 30,000 sporulated oocysts. Individual body weight was taken daily and percent weight change was computed to assess severity of infection, as expressed by Visco and Burns (1972). Birds that died were necropsied and cecal lesion scores were graded according to methods by Johnson and Reid (1970). They used a 0 to 4 scoring system with 1 for few lesions, 2 for slight lesions, 3 for many lesions and considerable blood, and 4 for severe lesions and large amount of blood. Experiment 2. A total of 210 15-day-old birds were allotted into 7 groups of 3 replicates each with 10 chickens per replicate. The groups consisted of those infected fed a ration containing amprolium plus ethopabate, and a combination of the coccidiostat and one of 4 antibiotics, i.e., thiopeptin, bacitracin, penicillin, or chlortetracycline. The two controls were an infected, unmedicated group and an uninfected, unmedicated group. The respective rations were provided continuously starting one day before coccidia exposure until 7 days after infection. Water was available ad libitum. The E. tenella used was a coccidiostat-resistant strain which obtained from a local broiler house, separated by a single-oocyst method, and propagated through chickens under strictly isolated conditions. This strain was tested previously and found to be resistant to amprolium plus ethopabate, 125 plus 8 mg./kg., in the feed. Chickens in infected groups each were given a single oral dose of 30,000 sporulated oocysts. Individual body weight taken and necropsy procedures were the same as those in the previous experiment. Statistical Analysis. Data on percent daily weight change after angular transformation, weight gain and number of dead birds were subjected to analysis of variance and Dun-
Downloaded from http://ps.oxfordjournals.org/ at UCSF Library on April 11, 2015
Birds. Day old broiler males, Arbor AcreVantress crossbreed, were purchased from a local hatchery and were reared in conventional electrically heated battery brooders. For experiments, they were caged in batteries in an air-conditioned room with continuous artificial illumination.
661
662
O. O H E AND A.
TABLE 1.
ARAKAWA
-Effect of feed additive antibiotics on weight gain, mortality and lesion score in chickens infected with E. tenella (Experiment 1)
No. of replicates 1 3 3 3 3 3 3
Av. weight gain Index gm. 70.4 150bc 118c 55.4 154bc 72.3 186ab 87.3 119c 55.9 213a 100
Av. no. of birds died/ rep.
Av. lesion score in dead birds 4.0 4.0 4.0 4.0 4.0
Supplement in feed (mg./kg.) Inf. 2.3a thiopeptin 2 4.6 Inf. bacitracin 20 2.0a Inf. penicillin 12 1.3ab Inf. chlortetracycline 22 2.3a Inf. unmed. None 0b Uninf. unmed. None 'Each replicate had 10 chickens. Any figures within a column having the same common letter do not differ significantly at the 5% level of probability. Group
Downloaded from http://ps.oxfordjournals.org/ at UCSF Library on April 11, 2015
c a n ' s new multiple range test (P = 0.05) (Steel and Torrie, 1960). RESULTS Experiment 1. Infection of E. tenella reduced average weight gains in all infected chickens when compared with uninfected unmedicated controls (Table 1). T h e gain in chickens infected and medicated with thiopeptin or penicillin was greater than those in infected unmedicated controls, but the difference was not statistically significant (P > 0.05). Infected bird's on feed containing bacitracin and those on basal ration were equally depressed. Chickens given chlortetracycline w e r e also d e p r e s s e d by the coccidia infection as compared with uninfected control, h o w e v e r there was no statistical difference (P > 0.05) in the gain between the two groups. Average percent daily weight change of infected groups were lower than that of uninfected control b e t w e e n days 3 and 4, 4 and 5, and 5 and 6 after infection (Fig. 1). H o w e v e r significant difference (P < 0.05) in the weight change between infected groups and uninfected control was noted only bet w e e n 4 and 5 d a y s after infection. T h e weight change of birds on ration containing bacitracin was the lowest a m o n g infected g r o u p s .
LU O
z: < x u X
£
0
LU
o -4 o: a. -6 LU
_i_
_i_
3-4
4-5
5-6
DAY
AFTER
6-7
INFECTION
FIG. 1. Average percent daily weight change of chickens infected medicated via the feed (mg. /kg.) with antibiotic; thiopeptin, 2 (O); bacitracin, 20 (O); penicillin, 12 (D);or chlortetracycline, 22 (A); and infected unmedicated (x) and uninfected unmedicated (+) controls after oral inoculation of E. tenella oocysts (Experiment 1).
663
ANTIBIOTICS AND EIMERIA TENELLA
The weight change in all infected birds reached the same level as those of uninfected control birds between 6 and 7 days after infection. Number of birds dead of cecal coccidiosis in group infected and medicated with bacitracin was significantly greater (P < 0.05) than that of other infected groups. Among these groups, there were no statistical differences (P > 0.05) in mortality. All birds dying during the experiment showed severe cecal haemorrhage.
DISCUSSION The present experiment confirms the earlier findings that infected chickens on the basal ration and those on antibiotic diets were equally depressed by E. tenella infection and that when chickens were infected with amprolium plus ethopabate-resistant strain, chickens on basal ration, those on ration
TABLE 2.- -Effect of feed additive antibiotics on weight gain, mortality and lesion score in chickens
infected with a coccidiostat-resistant strain o/E. tenella (Experiment 2)
Group Inf. Inf. Inf. Int. Inf. Inf. unmed. Uninf. unmed.
Supplement in feed (mg./kg.) amprolium 125 ethopabate 8 thiopeptin 2 amprolium 2 ethopabate 8 bacitracin 20 amprolium 125 ethopabate 8 penicillin 12 amprolium 125 ethopabate 8 chlortetracycline 22 amprolium 125 ethopabate 8 None None
No. of replicates ' 3
Av. weignt gain Index gm. 75.0 165a
Av. no. of birds . died/ rep. 1.3bc
Av. lesion score in dead birds 4.0
3
172a
78.2
l.Obc
4.0
3
154a
70.0
3.7a
4.0
3
179a
81.3
1.3bc
4.0
3
169a
76.8
1.3bc
3.8
3 3
143a 220
65.0 100
2.3ab 0c
4.0
'Each replicate had 10 chickens. Any figures within a column having the same superscript do not differ significantly at the 5% level of probability.
Downloaded from http://ps.oxfordjournals.org/ at UCSF Library on April 11, 2015
Experiment 2. Infection with a coccidiostatresistant strain of E. tenella resulted in significant (P < 0.05) weight depression (Table 2). Birds in groups infected and medicated with either amprolium plus ethopabate or a combination of the coccidiostat and antibiotic attained greater weight gain than in chickens in infected control group. However differences in the weight gain among all infected groups were not statistically significant (P > 0.05). Based on average percent daily weight
change, chickens in infected groups were severely depressed by coccidia infection (Fig. 2). The weight changes of infected groups were significantly lower (P < 0.05) than those of uninfected controls only between 4 and 5 days after infection. Birds on ration containing bacitracin were the only group which lost body weight between 4 and 5 days after infection. Average number of birds dead due to coccidiosis in infected controls and infected fed dietary bacitracin was significantly greater (P < 0.05) than that of other infected groups. There was severe haemorrhage in ceca of all birds that died and were necropsied.
664
O. OHE AND A. ARAKAWA
I0r +•— UJ
O z
E.
BROTSKY
Egg Prod. Conf., Cornell Univ., Ithaca, N.Y., 23-26. Mountney, G. J., and F. C. Arganosa, 1963. The effect of phosphates on moisture absorption, retention and cooking losses of broiler carcasses. Poultry Sci. 42: 384-388. Sato, K., and G. R. Hegarty, 1971. Warmed-over flavor in cooked meats. J. Food Sci. 36: 1098-1102. Stadelman, W. J., R. B. Harrington and K. K. Hale, 1971. Improving turkey meat quality by carcass
injection. Poultry Sci. 50: 898-900. Thomson, J. E., 1964. Effect of polyphosphates on oxidative deterioration of commercially cooked fryer chickens. Food Technol. 18: 147-148. Turner, E. W., W. D. Paynter, F. J. Montie, M. W. Bessert, G. M. Struck and F. C. Olson, 1954. Use of the 2-thiobarbituric acid reagent to measure rancidity in frozen pork. Food Technol. 8: 326-329.
O.
O H E AND A.
ARAKAWA
Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., 2-1-6, Kashima-cho, Osaka 532, Japan
Yodogawa-ku,
(Received for publication June 30, 1975)
ABSTRACT Two experiments were performed to study the effect of dietary antibiotics on percent daily weight change, mortality and gross cecal pathology in chickens during the critical phase of Eimeria tenella infection. In the first experiment, chickens were continuously fed ration containing thiopeptin, 2 mg./kg.; bacitracin, 20 mg./kg.; penicillin, 12 mg./kg.; or chlortetracycline, 22 mg./kg. One day after antibiotic feed was given, each bird received an oral inoculation of 30,000 sporulated oocysts. In the second experiment, chickens were consecutively fed ration containing amprolium plus ethopabate, 125 plus 8 mg./kg., and a combination of the coccidiostat and one of 4 antibiotics; thiopeptin, bacitracin, penicillin, or chlortetracycline. One day after medicated feed was given, birds were each given an oral inoculation of 30,000 amprolium plus ethopabate-resistant E. tenella oocysts. The experiments were terminated 7 days after coccidia exposure. In both experiments, E. tenella infection resulted in depression in all birds of infected groups. Average percent weight change of infected birds was significantly lower than that of uninfected unmedicated control between 4 and 5 days after infection. Significantly greater number of birds died of cecal coccidiosis in group fed dietary bacitracin than that of other infected groups. Dietary antibiotics did not reduce gross cecal lesions. POULTRY SCIENCE 55: 660-665, 1976
INTRODUCTION
V
I S C O and Burns (1972) reported that the p e r c e n t daily weight change is an important p a r a m e t e r to assess the severity of cecal coccidiosis caused b y Eimeria tenella. T h e y found that the weight change of infected conventionals w a s lower than that of infected bacteria-free chicks between days 4 and 5, 5 and 6, and 6 and 7 after infection. Mortality rate and cecal gross lesions at necropsy were greater in conventional infected chickens than those found in germ-free chickens (Visco and Burns, 1972; Radhakrishnan and Bradley, 1973; J o h n s o n et al., 1973).
Previous work d e m o n s t r a t e d that w h e n chickens were infected with E. tenella continuous use of antibiotic; thiopeptin, zinc bacitracin, penicillin, o r c h l o r t e t r a c y c l i n e ; via the feed for 3 w e e k s p r o m p t e d recovery from depressed b o d y weight as c o m p a r e d with chickens fed basal ration, and that w h e n birds were infected with amprolium plus ethopabate-resistant strain of E. tenella a combination of antibiotic and amprolium plus ethopabate in the feed for 3 w e e k s resulted in higher weight attained than amprolium plus ethopabate alone (Ohe and A r a k a w a , 1975). In the present experiment, emphasis was placed on the effect of these feed additive antibiotics
Downloaded from http://ps.oxfordjournals.org/ at UCSF Library on April 11, 2015
Effect of Dietary Antibiotics on Chickens Infected with Eimeria tenella
ANTIBIOTICS AND EIMERIA TENELLA
on percent daily weight change, mortality and gross cecal pathology in chickens during the critical phase of cecal coccidiosis. Two experiments were performed: E. tenella infection in the presence of antibiotics in the feed and amprolium plus ethopabate-resistant E. tenella infection in the presence of antibiotics and the coccidiostat. MATERIALS AND METHODS
Diet. The composition of the basal ration is reported previously (Arakawa and Ohe, 1975). Medicated diet was prepared by mixing the basal ration with a measured amount of commercial premix. Levels of antibiotic and coccidiostat in feed (mg./kg.) were: thiopeptin,' 2; zinc bacitracin, 2 20; procaine penicillin G,3 12; chlortetracycline hydrochloride, 4 22; and amprolium plus ethopabate, 5 125 plus 8. Experiment 1. A total of 180 chickens, 15 days old, were divided into 6 groups of 3 replicates each with 10 chickens per replicate. The groups consisted of those infected fed a ration containing either thiopeptin, bacitracin, penicillin, or chlortetracycline. The two groups were an infected, unmedicated group and an uninfected, unmedicated group. The respective rations and water were given continuously beginning one day prior to coccidia exposure until 7 days after infection. Fresh oocyst cultures were prepared routinely from 1. 2. 3. 4.
Fujisawa Pharmaceutical Co., Ltd., Osaka. Nippon Kayaku Co., Ltd., Osaka. Taito Pfizer Co., Ltd., Tokyo. Takeda Chemical Industries, Osaka.
5. Marupi-Merck, Sharp and Dohme, Osaka.
donor birds 7 to 8 days after infection. Birds in infected groups each received an oral inoculation of 30,000 sporulated oocysts. Individual body weight was taken daily and percent weight change was computed to assess severity of infection, as expressed by Visco and Burns (1972). Birds that died were necropsied and cecal lesion scores were graded according to methods by Johnson and Reid (1970). They used a 0 to 4 scoring system with 1 for few lesions, 2 for slight lesions, 3 for many lesions and considerable blood, and 4 for severe lesions and large amount of blood. Experiment 2. A total of 210 15-day-old birds were allotted into 7 groups of 3 replicates each with 10 chickens per replicate. The groups consisted of those infected fed a ration containing amprolium plus ethopabate, and a combination of the coccidiostat and one of 4 antibiotics, i.e., thiopeptin, bacitracin, penicillin, or chlortetracycline. The two controls were an infected, unmedicated group and an uninfected, unmedicated group. The respective rations were provided continuously starting one day before coccidia exposure until 7 days after infection. Water was available ad libitum. The E. tenella used was a coccidiostat-resistant strain which obtained from a local broiler house, separated by a single-oocyst method, and propagated through chickens under strictly isolated conditions. This strain was tested previously and found to be resistant to amprolium plus ethopabate, 125 plus 8 mg./kg., in the feed. Chickens in infected groups each were given a single oral dose of 30,000 sporulated oocysts. Individual body weight taken and necropsy procedures were the same as those in the previous experiment. Statistical Analysis. Data on percent daily weight change after angular transformation, weight gain and number of dead birds were subjected to analysis of variance and Dun-
Downloaded from http://ps.oxfordjournals.org/ at UCSF Library on April 11, 2015
Birds. Day old broiler males, Arbor AcreVantress crossbreed, were purchased from a local hatchery and were reared in conventional electrically heated battery brooders. For experiments, they were caged in batteries in an air-conditioned room with continuous artificial illumination.
661
662
O. O H E AND A.
TABLE 1.
ARAKAWA
-Effect of feed additive antibiotics on weight gain, mortality and lesion score in chickens infected with E. tenella (Experiment 1)
No. of replicates 1 3 3 3 3 3 3
Av. weight gain Index gm. 70.4 150bc 118c 55.4 154bc 72.3 186ab 87.3 119c 55.9 213a 100
Av. no. of birds died/ rep.
Av. lesion score in dead birds 4.0 4.0 4.0 4.0 4.0
Supplement in feed (mg./kg.) Inf. 2.3a thiopeptin 2 4.6 Inf. bacitracin 20 2.0a Inf. penicillin 12 1.3ab Inf. chlortetracycline 22 2.3a Inf. unmed. None 0b Uninf. unmed. None 'Each replicate had 10 chickens. Any figures within a column having the same common letter do not differ significantly at the 5% level of probability. Group
Downloaded from http://ps.oxfordjournals.org/ at UCSF Library on April 11, 2015
c a n ' s new multiple range test (P = 0.05) (Steel and Torrie, 1960). RESULTS Experiment 1. Infection of E. tenella reduced average weight gains in all infected chickens when compared with uninfected unmedicated controls (Table 1). T h e gain in chickens infected and medicated with thiopeptin or penicillin was greater than those in infected unmedicated controls, but the difference was not statistically significant (P > 0.05). Infected bird's on feed containing bacitracin and those on basal ration were equally depressed. Chickens given chlortetracycline w e r e also d e p r e s s e d by the coccidia infection as compared with uninfected control, h o w e v e r there was no statistical difference (P > 0.05) in the gain between the two groups. Average percent daily weight change of infected groups were lower than that of uninfected control b e t w e e n days 3 and 4, 4 and 5, and 5 and 6 after infection (Fig. 1). H o w e v e r significant difference (P < 0.05) in the weight change between infected groups and uninfected control was noted only bet w e e n 4 and 5 d a y s after infection. T h e weight change of birds on ration containing bacitracin was the lowest a m o n g infected g r o u p s .
LU O
z: < x u X
£
0
LU
o -4 o: a. -6 LU
_i_
_i_
3-4
4-5
5-6
DAY
AFTER
6-7
INFECTION
FIG. 1. Average percent daily weight change of chickens infected medicated via the feed (mg. /kg.) with antibiotic; thiopeptin, 2 (O); bacitracin, 20 (O); penicillin, 12 (D);or chlortetracycline, 22 (A); and infected unmedicated (x) and uninfected unmedicated (+) controls after oral inoculation of E. tenella oocysts (Experiment 1).
663
ANTIBIOTICS AND EIMERIA TENELLA
The weight change in all infected birds reached the same level as those of uninfected control birds between 6 and 7 days after infection. Number of birds dead of cecal coccidiosis in group infected and medicated with bacitracin was significantly greater (P < 0.05) than that of other infected groups. Among these groups, there were no statistical differences (P > 0.05) in mortality. All birds dying during the experiment showed severe cecal haemorrhage.
DISCUSSION The present experiment confirms the earlier findings that infected chickens on the basal ration and those on antibiotic diets were equally depressed by E. tenella infection and that when chickens were infected with amprolium plus ethopabate-resistant strain, chickens on basal ration, those on ration
TABLE 2.- -Effect of feed additive antibiotics on weight gain, mortality and lesion score in chickens
infected with a coccidiostat-resistant strain o/E. tenella (Experiment 2)
Group Inf. Inf. Inf. Int. Inf. Inf. unmed. Uninf. unmed.
Supplement in feed (mg./kg.) amprolium 125 ethopabate 8 thiopeptin 2 amprolium 2 ethopabate 8 bacitracin 20 amprolium 125 ethopabate 8 penicillin 12 amprolium 125 ethopabate 8 chlortetracycline 22 amprolium 125 ethopabate 8 None None
No. of replicates ' 3
Av. weignt gain Index gm. 75.0 165a
Av. no. of birds . died/ rep. 1.3bc
Av. lesion score in dead birds 4.0
3
172a
78.2
l.Obc
4.0
3
154a
70.0
3.7a
4.0
3
179a
81.3
1.3bc
4.0
3
169a
76.8
1.3bc
3.8
3 3
143a 220
65.0 100
2.3ab 0c
4.0
'Each replicate had 10 chickens. Any figures within a column having the same superscript do not differ significantly at the 5% level of probability.
Downloaded from http://ps.oxfordjournals.org/ at UCSF Library on April 11, 2015
Experiment 2. Infection with a coccidiostatresistant strain of E. tenella resulted in significant (P < 0.05) weight depression (Table 2). Birds in groups infected and medicated with either amprolium plus ethopabate or a combination of the coccidiostat and antibiotic attained greater weight gain than in chickens in infected control group. However differences in the weight gain among all infected groups were not statistically significant (P > 0.05). Based on average percent daily weight
change, chickens in infected groups were severely depressed by coccidia infection (Fig. 2). The weight changes of infected groups were significantly lower (P < 0.05) than those of uninfected controls only between 4 and 5 days after infection. Birds on ration containing bacitracin were the only group which lost body weight between 4 and 5 days after infection. Average number of birds dead due to coccidiosis in infected controls and infected fed dietary bacitracin was significantly greater (P < 0.05) than that of other infected groups. There was severe haemorrhage in ceca of all birds that died and were necropsied.
664
O. OHE AND A. ARAKAWA
I0r +•— UJ
O z
