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Diclazuril, a New Broad Spectrum Anticoccidial Drug in Chickens.
Diclazuril, a New Broad Spectrum Anticoccidial Drug in Chickens. 2. Battery Trials O. VANPARIJS, R. MARSBOOM, L. HERMANS, and L. VAN DER FLAES
(Received for publication May 9, 1988) ABSTRACT Battery trials have confirmed the broad spectrum anticoccidial activity of diclazuril as previously reported in dose titration studies. The advocated dose level of 1 ppm in the diet demonstrated excellent activity against the economically most important Eimeria species. At this dose level, body weight gains were comparable to those of uninfected, unmedicated controls and the oocyst production was negative in most species. Lesion scores and dropping scores were nil or highly reduced. An E. maxima147 strain, less sensitive to ionophores, also responded well to diclazuril. It was concluded that diclazuril is a promising anticoccidial for the control of all species of coccidia that cause losses to the poultry industry. (Key words: diclazuril, coccidiosis, poultry, battery trials, efficacy) 1989 Poultry Science 68:496-500 INTRODUCTION
Diclazuril has been shown to have a high broad spectrum activity against the major pathogenic Eimeria species in chickens (Vanparijs et al., 1988). Dose titration studies indicated that the drug is optimally effective at 1 ppm in the diet. Although these results suggested that diclazuril may be a useful anticoccidial, battery trials were necessary for a better evaluation of the activity. The purpose of this study was to determine the effectiveness of diclazuril in battery trials. MATERIALS AND METHODS
One-day-old Hisex cockerels were obtained from a commercial hatchery (Moonen Hatchery, Poppel, Belgium) and reared on batteries in isolation rooms to insure complete freedom from coccidiosis. Birds were fed a commercial laying-hen feed (Boerenbond Diets # 281, Merksem, Belgium) without any anticoccidial. On Day 21 birds were weighed individually, divided into groups of eight chickens with comparable body weights per group, and placed individually in wire-floored cages with feed and water ad libitum. Birds were inoculated with a single Eimeria strain at 21 days of age (Day 0 of the experiment). Replicates of eight birds were used sequentially. Two Eimeria species used, E. tenella and E. acervulina, were pathogenic laboratory strains isolated from the field in Belgium and
maintained without medication for many years in the laboratory. Four other pathogenic species used, E. necatrix, E. brunetti, E. maxima-H, and E. mitis, were provided by H. D. Chapman of the Houghton Poultry Research Station (Rose, 1967; Long and Rose, 1970). A highly pathogenic strain of E. maxima 147, less sensitive to ionophores, was also used, provided by L. McDougald of the University of Georgia, Athens, GA. The sporulated oocysts, suspended in tap-water and properly agitated, were administered by gavage in 1-mL volumes directly into the chicken's crop by means of a plastic tube attached to a calibrated syringe. The number of oocysts given per bird depended upon the pathogenicity of the species used: E. tenella, 100,000; E. acervulina, 1,000, 000; E. necatrix, 25,000; E. brunetti, 100,000; E. maxima-H, 200,000; E. maxima-147, 50, 000; and E. mitis, 500,000. The medicated feed was prepared by blending diclazuril (CLINACOX® Janssen Pharmaceutica, Beerse, Belgium) as a .5% formulated compound to obtain the desired concentrations in the feed of either 2, 1, .5, or .1 ppm. The medicated feed was provided ad libitum from Day 1 (1 day before oocyst administration) until Day 6 postinoculation (p.i.). The evaluation of the anticoccidial efficacy of diclazuril was based on survival, weight gain, lesion and dropping scores, and oocyst counts. The infected, medicated birds were therefore compared with infected, unmedicated and uninfected, unmedicated birds. Daily ob-
496
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on June 17, 2014
Janssen Pharmaceutica, B-2340 Beerse, Belgium
497
DICLAZURIL FOR PREVENTION OF COCCIDIOSIS TABLE 1. Anticoccidial activity of diclazuril against Eimeria tenella in battery trials Diclazuril concentration in feed
Mean of replicate values Coccidial infection
(ppm)
+ + + +
.1 .5 1
(g) 73* 19" 72' 70* 71"
Lesion score
Dropping score
OPG 1 3
0"
0b
3.5'
2.1"
0" 0" 0"
0b 0b 0"
Mortality 2
(xlO )
(n/N)
0b
0/32 1/32 0/16 0/32 0/32
469*
0" 0b 0"
"••"Values within a column with no common superscripts are significantly different (P<05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
servations were made on mortality and body weight. All birds who died during the experiment were autopsied for lesion scores. At the end of the experiment (Day 6 p.i.) surviving birds were killed and autopsied for lesion scores, graded from 0 to 4 as described by Johnson and Reid (1970). Fecal samples were collected on Day 6 p.i. for oocyst counts by the McMaster method (Parfitt, 1958) and expressed as number of oocysts per gram feces (O.P.G.). On Days 4 and 5 p.i. droppings were scored from 0 to 3 as described by Ryley and Wilson (1975). Data obtained for the various parameters have been analyzed by analysis of variance, and means were separated by Duncan's multiple comparison test (Duncan, 1957) as provided by the SAS statistical analysis program (SAS, 1979). The test allows comparison of different treatments with one another. It is also applicable in those cases where the numbers of replicates in the treatment groups are different.
RESULTS
The anticoccidial activity of diclazuril against six major pathogenic Eimeria species is summarized in Tables 1 to 7. The results will be presented separately for each species. Eimeria tenella. Weight gains of all medicated birds, even at the lowest dose level of .1 ppm, were comparable to gains of the uninfected, unmedicated controls (Table 1). Lesions were fully prevented and dropping scores and oocyst counts were reduced to zero. In the diclazuril groups no deaths occurred, compared with 1 death out of 32 birds in the infected, unmedicated controls. Eimeria acervulina. Weight gain of the 1ppm diclazuril group was almost equal to that of the uninfected, unmedicated controls (Table 2). This dose level was necessary to prevent lesions and to reduce dropping scores and oocyst counts to zero. Oocyst production, at .1 and .5-ppm treatment levels, was also greatly
TABLE 2. Anticoccidial activity of diclazuril against Eimeria acervulina in battery trials Diclazuril concentration in feed
Mean of replicate values Coccidial infection
(ppm)
0 0 .1 .5 1
+ + + +
Weight
gam (g) 71' 2f/ 42" 58'"
70*
Lesion score
Dropping score
0°
0
2.2* 1.2"
2.4*
.3' 0=
C
.9" 1.2
0=
OPG 1
Mortality 2
(xlO 3 )
(n/N)
0"
0/32 0/32 0/16 0/32 0/32
407" 127"
56" 0"
"Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on June 17, 2014
_
0 0
Weight gain
498
VANPARIJS ET AL. TABLE 3. Anticoccidial activity of diclazuril against Eimeria necatrix in battery trials
Diclazuril concentration in feed
+ + + +
Weight gain (g) 63' 24" 59" 64' 65'
Lesion score
Dropping score
OPG1 3
0" 3.4" 1.3" .5C A"6
0" 2.3" 0" 0b 0b
(xlO ) 0" 74" 0" 0" 0b
Mortality2 (n/N) 0/40 3/40 0/24 0/40 0/40
'""Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
reduced compared with levels for infected, unmedicated controls. No deaths occurred in any groups. Eimeria necatrix. At 1 and .5-ppm diclazuril treatment levels weight gains of birds exceeded that of the uninfected, unmedicated controls and even at .1 ppm, weight gain remained comparable to the control value (Table 3). All dose levels reduced dropping scores and oocyst counts to zero. In the infected, unmedicated controls 3 birds out of 40 died. Eimeria brunetti. The morbidity of this Eimeria species was very high as reflected by the severely lowered weight gain in the infected, unmedicated controls (Table 4). In contrast, weight gains in the 1 and .5-ppm medicated birds remained comparable to those of the uninfected, unmedicated controls. At both dose levels lesions and dropping scores were greatly reduced and the oocyst production was nil. No deaths occurred in any groups.
Eimeria maxima. The morbidity of the E. maxima-H strain was low although lowered weight gain and lesion scores were observed in the infected, unmedicated controls (Tables 5 and 6). The E. maxima-147 strain proved to be more pathogenic, as its effect on weight gain was much more pronounced. At .5 and 1ppm treatment levels the activities of diclazuril against both E. maxima strains were comparable. Lesions were greatly reduced and dropping scores were very low. Oocyst production was fully prevented. The 2-ppm dose level against E. maxima-147 improved weight gain but a low lesion score could not be prevented. Deaths did not occur in any groups. Eimeria mitis. This species was the least sensitive to diclazuril (Table 7). At the 1-ppm treatment level the weight gain was less than that of the uninfected, unmedicated controls, but lesion and dropping scores and oocyst production were greatly reduced compared
TABLE 4. Anticoccidial activity of diclazuril against Eimeria brunetti in battery trials Diclazuril concentration in feed (ppm) 0 0 .1 .5 1
Mean of replicate values Coccidial infection
+ + + +
Weight gain (g) 60" 6C 36" 55" 56"
Lesion score
Dropping score
OPG1 3
0= 2.9* .8" .4C .2°
0° 2.7' .9" .3C .l c
(xlO ) 0b 143" 22" 0" 0"
"""Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
Mortality2 (n/N) 0/32 0/32 0/24 0/32 0/32
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on June 17, 2014
(ppm) 0 0 .1 .5 1
Mean of replicate values Coccidial infection
499
DICLAZURIL FOR PREVENTION OF COCCIDIOSIS TABLE 5. Anticoccidial activity of diclazuril against Eimeria maxima-H in battery trials Diclazuril concentration in feed
Mean of replicate values Coccidial infection
(ppm)
+ + + +
.1 .5 1
(g) 72* 56" 64*" 66*"
68*
Lesion score
Dropping score
OPG1 3
0° 2.4* 1.8*" 1.3" 1.3"
0" .2* .025*" .05*" .025*"
Mortality2
(xlO )
(n/N)
0" 27* 0" 0" 0"
0/32 0/32 0/32 0/32 0/32
•""Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
TABLE 6. Anticoccidial activity of diclazuril against Eimeria maxima-147 in battery trials Diclazuril concentration in feed
Mean of replicate values Coccidial infection
(ppm)
_
0 0
+ + + + +
.1 .5 1 2
Weight gain
(g) 70* 22c 42* 60" 61" 71*
Lesion score
Dropping score
OPG1 3
(xlO )
(n/N)
0"
0/40 0/40 0/24 0/40 0/40 0/16
0*
0"
2.5* 1.2" 1.3" 1.1" 1.1"
1.9*
343*
.3" 0"
26" 0" 0" 0"
.025"
0b
Mortality2
"Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
TABLE 7. Anticoccidial activity of diclazuril against Eimeria mitis in battery trials Mean of replicate values concentration in feed
Coccidial infection
(ppm)
0 0 .1 .5 1
_ + + + +
Weight gain
(g) 57* 21" 26" 33c 46"
Lesion score
Dropping score
OPG' 3
0*
0"
2.2* 1.0" .6"" .41"
1.9* 1.4" 1.3"
.5°
Mortality2
(xlO )
(n/N)
0°
0/24 0/24 0/24 0/24 0/24
248*
78" 47* 17c
""^Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on June 17, 2014
_
0 0
Weight gain
500
VANPARIJS ET AL.
with results for the infected, unmedicated controls. Deaths were not observed.
used by the industry, more floor pen trials and field trials must be conducted.
DISCUSSION
ACKNOWLEDGMENTS
We wish to thank J. Frederickx and Y. Devocht for secretarial work. The assistance of P. Lewi for the statistical analysis is gready appreciated. REFERENCES Duncan, D. B., 1957. /-Test and intervals for comparisons suggested by the data. Biometrics 31:339-359. 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. Long, P. L., and M. E. Rose, 1970. Extended schizogony of Eimeria mivati in betametazone-treated chickens. Parasitology 60:147-155. Parfitt, J. W., 1958. A technique for the enumeration of helminth eggs and protozoan cysts in faeces from farm animals in Britain. Lab. Pract. 7:353-356. Rose, M. E., 1967. Immunity to Eimeria brunetti and Eimeria maxima infections in the fowl. Parasitology 57:363-370. Ryley, J. F., and R. G. Wilson, 1975. Laboratory studies with some recent anticoccidials. Parasitology 70:203-222. SAS, 1979. SAS User's Guide. SAS Inst. Inc., Cary, NC. Vanparijs, O., R. Marsboom, and L. Desplenter, 1989. Diclazuril, a new broad spectrum anticoccidial drug in chickens. 1. Dose titration studies and pilot floor pen trials. Poultry Sci. 68:489-495.
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on June 17, 2014
These data confirm the findings in the dose titration studies (Vanparijs et al., 1989). The results obtained in these battery trials confirm that diclazuril is a highly active broad spectrum anticoccidial against the economically most important species of Eimeria. The advocated 1-ppm dose level in the diet permitted excellent body weight gain during the critical periods of the infection, with suppression of oocyst production in most species. Lesions and dropping scores were nil or gready reduced. Lesions observed in both E. maxima species were significantly lower at almost all dose levels. The E. maxima-147 strain, less sensitive to ionophores, responded well to diclazuril at 1 and even at .5 ppm as reflected by negative oocyst counts, highly reduced lesion scores, and almost zero dropping scores. Also weight gains were comparable to those of the uninfected, unmedicated controls. The results obtained in battery trials indicate that diclazuril is an effective broad spectrum anticoccidial drug. Before it can be
(Received for publication May 9, 1988) ABSTRACT Battery trials have confirmed the broad spectrum anticoccidial activity of diclazuril as previously reported in dose titration studies. The advocated dose level of 1 ppm in the diet demonstrated excellent activity against the economically most important Eimeria species. At this dose level, body weight gains were comparable to those of uninfected, unmedicated controls and the oocyst production was negative in most species. Lesion scores and dropping scores were nil or highly reduced. An E. maxima147 strain, less sensitive to ionophores, also responded well to diclazuril. It was concluded that diclazuril is a promising anticoccidial for the control of all species of coccidia that cause losses to the poultry industry. (Key words: diclazuril, coccidiosis, poultry, battery trials, efficacy) 1989 Poultry Science 68:496-500 INTRODUCTION
Diclazuril has been shown to have a high broad spectrum activity against the major pathogenic Eimeria species in chickens (Vanparijs et al., 1988). Dose titration studies indicated that the drug is optimally effective at 1 ppm in the diet. Although these results suggested that diclazuril may be a useful anticoccidial, battery trials were necessary for a better evaluation of the activity. The purpose of this study was to determine the effectiveness of diclazuril in battery trials. MATERIALS AND METHODS
One-day-old Hisex cockerels were obtained from a commercial hatchery (Moonen Hatchery, Poppel, Belgium) and reared on batteries in isolation rooms to insure complete freedom from coccidiosis. Birds were fed a commercial laying-hen feed (Boerenbond Diets # 281, Merksem, Belgium) without any anticoccidial. On Day 21 birds were weighed individually, divided into groups of eight chickens with comparable body weights per group, and placed individually in wire-floored cages with feed and water ad libitum. Birds were inoculated with a single Eimeria strain at 21 days of age (Day 0 of the experiment). Replicates of eight birds were used sequentially. Two Eimeria species used, E. tenella and E. acervulina, were pathogenic laboratory strains isolated from the field in Belgium and
maintained without medication for many years in the laboratory. Four other pathogenic species used, E. necatrix, E. brunetti, E. maxima-H, and E. mitis, were provided by H. D. Chapman of the Houghton Poultry Research Station (Rose, 1967; Long and Rose, 1970). A highly pathogenic strain of E. maxima 147, less sensitive to ionophores, was also used, provided by L. McDougald of the University of Georgia, Athens, GA. The sporulated oocysts, suspended in tap-water and properly agitated, were administered by gavage in 1-mL volumes directly into the chicken's crop by means of a plastic tube attached to a calibrated syringe. The number of oocysts given per bird depended upon the pathogenicity of the species used: E. tenella, 100,000; E. acervulina, 1,000, 000; E. necatrix, 25,000; E. brunetti, 100,000; E. maxima-H, 200,000; E. maxima-147, 50, 000; and E. mitis, 500,000. The medicated feed was prepared by blending diclazuril (CLINACOX® Janssen Pharmaceutica, Beerse, Belgium) as a .5% formulated compound to obtain the desired concentrations in the feed of either 2, 1, .5, or .1 ppm. The medicated feed was provided ad libitum from Day 1 (1 day before oocyst administration) until Day 6 postinoculation (p.i.). The evaluation of the anticoccidial efficacy of diclazuril was based on survival, weight gain, lesion and dropping scores, and oocyst counts. The infected, medicated birds were therefore compared with infected, unmedicated and uninfected, unmedicated birds. Daily ob-
496
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on June 17, 2014
Janssen Pharmaceutica, B-2340 Beerse, Belgium
497
DICLAZURIL FOR PREVENTION OF COCCIDIOSIS TABLE 1. Anticoccidial activity of diclazuril against Eimeria tenella in battery trials Diclazuril concentration in feed
Mean of replicate values Coccidial infection
(ppm)
+ + + +
.1 .5 1
(g) 73* 19" 72' 70* 71"
Lesion score
Dropping score
OPG 1 3
0"
0b
3.5'
2.1"
0" 0" 0"
0b 0b 0"
Mortality 2
(xlO )
(n/N)
0b
0/32 1/32 0/16 0/32 0/32
469*
0" 0b 0"
"••"Values within a column with no common superscripts are significantly different (P<05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
servations were made on mortality and body weight. All birds who died during the experiment were autopsied for lesion scores. At the end of the experiment (Day 6 p.i.) surviving birds were killed and autopsied for lesion scores, graded from 0 to 4 as described by Johnson and Reid (1970). Fecal samples were collected on Day 6 p.i. for oocyst counts by the McMaster method (Parfitt, 1958) and expressed as number of oocysts per gram feces (O.P.G.). On Days 4 and 5 p.i. droppings were scored from 0 to 3 as described by Ryley and Wilson (1975). Data obtained for the various parameters have been analyzed by analysis of variance, and means were separated by Duncan's multiple comparison test (Duncan, 1957) as provided by the SAS statistical analysis program (SAS, 1979). The test allows comparison of different treatments with one another. It is also applicable in those cases where the numbers of replicates in the treatment groups are different.
RESULTS
The anticoccidial activity of diclazuril against six major pathogenic Eimeria species is summarized in Tables 1 to 7. The results will be presented separately for each species. Eimeria tenella. Weight gains of all medicated birds, even at the lowest dose level of .1 ppm, were comparable to gains of the uninfected, unmedicated controls (Table 1). Lesions were fully prevented and dropping scores and oocyst counts were reduced to zero. In the diclazuril groups no deaths occurred, compared with 1 death out of 32 birds in the infected, unmedicated controls. Eimeria acervulina. Weight gain of the 1ppm diclazuril group was almost equal to that of the uninfected, unmedicated controls (Table 2). This dose level was necessary to prevent lesions and to reduce dropping scores and oocyst counts to zero. Oocyst production, at .1 and .5-ppm treatment levels, was also greatly
TABLE 2. Anticoccidial activity of diclazuril against Eimeria acervulina in battery trials Diclazuril concentration in feed
Mean of replicate values Coccidial infection
(ppm)
0 0 .1 .5 1
+ + + +
Weight
gam (g) 71' 2f/ 42" 58'"
70*
Lesion score
Dropping score
0°
0
2.2* 1.2"
2.4*
.3' 0=
C
.9" 1.2
0=
OPG 1
Mortality 2
(xlO 3 )
(n/N)
0"
0/32 0/32 0/16 0/32 0/32
407" 127"
56" 0"
"Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on June 17, 2014
_
0 0
Weight gain
498
VANPARIJS ET AL. TABLE 3. Anticoccidial activity of diclazuril against Eimeria necatrix in battery trials
Diclazuril concentration in feed
+ + + +
Weight gain (g) 63' 24" 59" 64' 65'
Lesion score
Dropping score
OPG1 3
0" 3.4" 1.3" .5C A"6
0" 2.3" 0" 0b 0b
(xlO ) 0" 74" 0" 0" 0b
Mortality2 (n/N) 0/40 3/40 0/24 0/40 0/40
'""Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
reduced compared with levels for infected, unmedicated controls. No deaths occurred in any groups. Eimeria necatrix. At 1 and .5-ppm diclazuril treatment levels weight gains of birds exceeded that of the uninfected, unmedicated controls and even at .1 ppm, weight gain remained comparable to the control value (Table 3). All dose levels reduced dropping scores and oocyst counts to zero. In the infected, unmedicated controls 3 birds out of 40 died. Eimeria brunetti. The morbidity of this Eimeria species was very high as reflected by the severely lowered weight gain in the infected, unmedicated controls (Table 4). In contrast, weight gains in the 1 and .5-ppm medicated birds remained comparable to those of the uninfected, unmedicated controls. At both dose levels lesions and dropping scores were greatly reduced and the oocyst production was nil. No deaths occurred in any groups.
Eimeria maxima. The morbidity of the E. maxima-H strain was low although lowered weight gain and lesion scores were observed in the infected, unmedicated controls (Tables 5 and 6). The E. maxima-147 strain proved to be more pathogenic, as its effect on weight gain was much more pronounced. At .5 and 1ppm treatment levels the activities of diclazuril against both E. maxima strains were comparable. Lesions were greatly reduced and dropping scores were very low. Oocyst production was fully prevented. The 2-ppm dose level against E. maxima-147 improved weight gain but a low lesion score could not be prevented. Deaths did not occur in any groups. Eimeria mitis. This species was the least sensitive to diclazuril (Table 7). At the 1-ppm treatment level the weight gain was less than that of the uninfected, unmedicated controls, but lesion and dropping scores and oocyst production were greatly reduced compared
TABLE 4. Anticoccidial activity of diclazuril against Eimeria brunetti in battery trials Diclazuril concentration in feed (ppm) 0 0 .1 .5 1
Mean of replicate values Coccidial infection
+ + + +
Weight gain (g) 60" 6C 36" 55" 56"
Lesion score
Dropping score
OPG1 3
0= 2.9* .8" .4C .2°
0° 2.7' .9" .3C .l c
(xlO ) 0b 143" 22" 0" 0"
"""Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
Mortality2 (n/N) 0/32 0/32 0/24 0/32 0/32
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on June 17, 2014
(ppm) 0 0 .1 .5 1
Mean of replicate values Coccidial infection
499
DICLAZURIL FOR PREVENTION OF COCCIDIOSIS TABLE 5. Anticoccidial activity of diclazuril against Eimeria maxima-H in battery trials Diclazuril concentration in feed
Mean of replicate values Coccidial infection
(ppm)
+ + + +
.1 .5 1
(g) 72* 56" 64*" 66*"
68*
Lesion score
Dropping score
OPG1 3
0° 2.4* 1.8*" 1.3" 1.3"
0" .2* .025*" .05*" .025*"
Mortality2
(xlO )
(n/N)
0" 27* 0" 0" 0"
0/32 0/32 0/32 0/32 0/32
•""Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
TABLE 6. Anticoccidial activity of diclazuril against Eimeria maxima-147 in battery trials Diclazuril concentration in feed
Mean of replicate values Coccidial infection
(ppm)
_
0 0
+ + + + +
.1 .5 1 2
Weight gain
(g) 70* 22c 42* 60" 61" 71*
Lesion score
Dropping score
OPG1 3
(xlO )
(n/N)
0"
0/40 0/40 0/24 0/40 0/40 0/16
0*
0"
2.5* 1.2" 1.3" 1.1" 1.1"
1.9*
343*
.3" 0"
26" 0" 0" 0"
.025"
0b
Mortality2
"Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
TABLE 7. Anticoccidial activity of diclazuril against Eimeria mitis in battery trials Mean of replicate values concentration in feed
Coccidial infection
(ppm)
0 0 .1 .5 1
_ + + + +
Weight gain
(g) 57* 21" 26" 33c 46"
Lesion score
Dropping score
OPG' 3
0*
0"
2.2* 1.0" .6"" .41"
1.9* 1.4" 1.3"
.5°
Mortality2
(xlO )
(n/N)
0°
0/24 0/24 0/24 0/24 0/24
248*
78" 47* 17c
""^Values within a column with no common superscripts are significantly different (P<.05). 'OPG = Number of oocysts per gram feces. 2 N = Total number of birds at risk; n = number of birds that died.
Downloaded from http://ps.oxfordjournals.org/ at Ernst Mayr Library of the Museum Comp Zoology, Harvard University on June 17, 2014
_
0 0
Weight gain
500
VANPARIJS ET AL.
with results for the infected, unmedicated controls. Deaths were not observed.
used by the industry, more floor pen trials and field trials must be conducted.
DISCUSSION
ACKNOWLEDGMENTS
We wish to thank J. Frederickx and Y. Devocht for secretarial work. The assistance of P. Lewi for the statistical analysis is gready appreciated. REFERENCES Duncan, D. B., 1957. /-Test and intervals for comparisons suggested by the data. Biometrics 31:339-359. 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. Long, P. L., and M. E. Rose, 1970. Extended schizogony of Eimeria mivati in betametazone-treated chickens. Parasitology 60:147-155. Parfitt, J. W., 1958. A technique for the enumeration of helminth eggs and protozoan cysts in faeces from farm animals in Britain. Lab. Pract. 7:353-356. Rose, M. E., 1967. Immunity to Eimeria brunetti and Eimeria maxima infections in the fowl. Parasitology 57:363-370. Ryley, J. F., and R. G. Wilson, 1975. Laboratory studies with some recent anticoccidials. Parasitology 70:203-222. SAS, 1979. SAS User's Guide. SAS Inst. Inc., Cary, NC. Vanparijs, O., R. Marsboom, and L. Desplenter, 1989. Diclazuril, a new broad spectrum anticoccidial drug in chickens. 1. Dose titration studies and pilot floor pen trials. Poultry Sci. 68:489-495.
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These data confirm the findings in the dose titration studies (Vanparijs et al., 1989). The results obtained in these battery trials confirm that diclazuril is a highly active broad spectrum anticoccidial against the economically most important species of Eimeria. The advocated 1-ppm dose level in the diet permitted excellent body weight gain during the critical periods of the infection, with suppression of oocyst production in most species. Lesions and dropping scores were nil or gready reduced. Lesions observed in both E. maxima species were significantly lower at almost all dose levels. The E. maxima-147 strain, less sensitive to ionophores, responded well to diclazuril at 1 and even at .5 ppm as reflected by negative oocyst counts, highly reduced lesion scores, and almost zero dropping scores. Also weight gains were comparable to those of the uninfected, unmedicated controls. The results obtained in battery trials indicate that diclazuril is an effective broad spectrum anticoccidial drug. Before it can be