Six floor pen experiments were conducted using approved
protocols and 23,676 broiler chickens. Bacitracin
methylene disalicylate at 0, 10, 25 and 50 grams per ton
of feed was used in five of the experiments, while 0, 5
and 50 grams per ton was used in one. Roxarsone at 0,
11.3, 22.7 and 45.4 grams per ton was used in five of the
experiments, while 0 and 45.4 grams per ton was used in
one. Monensin sodium at 110 grams per ton was included in
all experimental feeds. The experiments were designed to
test the effects of bacitracin methylene disalicylate in
the presence of monensin on body weight gains and feed
efficiency.
A description of the six experiments follows:
Experiment No: FV-B-29/30-74
Investigator:
Ralph V. Fell, Ph.D.
Box 488
Sheridan, AR 72150
The 56-day experiment was conducted at the S. B. Penick
Animal Research Farm, French Village, MO from January 3,
to February 28, 1974. The experiment consisted of 16
dietary treatments with three replicates of 70 one day
old Vantress X Hubbard broiler chickens placed randomly,
half male and half female in 48 pens. Each 9' x 6' pen
was identically equipped with an infrared brooder, two
tube type hanging feeders, and three Hart drinking cups.
The floors were concrete and covered with wood shavings.
The building was enclosed, continuously lighted and fan
ventilated. The desired levels of drugs being studied
were added to typical broiler starter/finisher rations
and fed for the entire growing period except that
monensin was withdrawn from the feed for the last five
days.
Experiment No: FV-B-29/30-74
Investigator:
Ralph V. Fell, Ph.D.
Box 488
Sheridan, AR 72150
The second of the 56-day experiments was conducted
concurrently with FV-B-29-74 in a second house at the S.
B. Penick Animal Research Farm, French Village, MO from
January 3 to February 28, 1974. This experiment consisted
of 16 dietary treatments with two replicates of 80 one-day
old Vantress X Hubbard broiler chickens, placed
randomly, half male and half female, in 32 pens. Each 6'
x 10' pen was identically equipped with an infrared
brooder, two tube type hanging feeders and three Hart
drinking cups. Wood shavings were used as litter. The
building was enclosed, continuously lighted and fan
ventilated. The desired levels of drugs being studied
were added to typical broiler starter/finisher rations
and fed for the entire growing period, except that
monensin was withdrawn from the feed for the last five
days.
Experiment No: GA-B-53-77
Investigator:
Robert K. Page, D.V.M.
Department of Avian Medicine
College of Veterinary Medicine
University of Georgia
Athens, GA
Monitor:
Ralph V. Fell, Ph.D.
Box 488
Sheridan, AR 72150
This 56-day experiment was conducted at Winder, GA under
the supervision of Dr. Robert K. Page from February 24,
to April 20, 1976. The experiment consisted of 16 dietary
treatments with three replicates of 60 one-day old
Hubbard X Hubbard broiler chickens, half male and half
female in each of 48 pens. Each 5' x 10' was identically
equipped with thermostatically controlled brooders,self
feeders and drinking fountains. New wood shavings were
spread over built up litter.
The desired level of drugs being studied were added to a
typical boiler starter/finisher ration and fed for the
entire growing period except that monensin was withdrawn
from the feed for the last five days.
Experiment No: 306-572-1-14
Investigators:
B. F. Schlegel, D.V.M.
Wheeler, AR
and
D. L. Gard, Ph.D.
Eli Lilly & Company
Greenfield, IN 46140
This 50-day experiment was conducted at facilities leased
by Eli Lilly & Company, Wheeler, AR beginning on December
8, 1971. The experiment consisted of six dietary
treatments with the negative controls being replicated
six times and the other four treatments being replicated
six times and the other four treatments being replicated
four times. One hundred one-day old male broiler chickens
were placed randomly in each of 28 pens. Each 8' x 10'
pen was equipped with area gas brooders, incandescent
light, two 18' tube feeders and one 18' diameter
automatic waterer. Reused litter was provided. The pens
were in a building which had a concrete block foundation,
wood frame walls, insulated ceiling, concrete floor and
thermostatically controlled glass curtains. The desired
levels of drugs being studied were added to a typical
starter/finisher broiler ration and fed for the entire
growing period except monensin was withdrawn from the
feed for the last five days.
Experiment No: 306-572-2-2
Investigators:
B. F. Schlegel, D.V.M.
Wheeler, AR
and
D. L. Gard, Ph.D.
Eli Lilly & Company
Greenfield, IN 46140
This 61-day experiment was conducted at the same
facilities as the previous experiment beginning February
28, 1972. The experiment consisted of 16 dietary
treatments. Four treatments were replicated three times
and the other 12 treatments were replicated four times.
One hundred Vantress X Arbor Acre broiler chickens, half
male and half female, were randomly distributed to each
of the 60 pens. The desired level of drugs being studied
were added to a typical starter/finisher broiler ration
and fed for the entire growing period except monensin was
withdrawn from the feed for the last five days.
Experiment No: 306-572-2-7
Investigators:
B. F. Schlegel, D.V.M.
Wheeler, AR
and
D. L. Gard, Ph.D.
Eli Lilly & Company
Greenfield, IN 46140
This 58-day experiment was conducted at the same
facilities as the previous experiment beginning May 9,
1972. The experiment consisted of 16 dietary treatments.
Four treatments were replicated three times and the other
12 treatments were replicated four times. One hundred
Vantress X Arbor Acre Broiler chickens, half male and
half female, were distributed randomly in each of the 60
pens. The desired levels of drugs being studied were
added to typical broiler and starter/finisher rations fed
for the entire growing period except monensin was
withdrawn from the feed for the last five days.
Floor Pen Experiments Summary
Six adequate and well-controlled floor pen experiments,
using approved protocols and 23,676 broiler chickens (in
five experiments equal numbers of males and females, in
one experiment all males) were conducted under conditions
simulating actual field use to determine the growth
promoting effects of bacitracin methylene disalicylate in
the presence of monensin. Although these experiments were
originally designed as titration studies, for purposes of
this submission, only the highest levels of bacitracin
methylene disalicylate (50 grams per ton) in the presence
of monensin (110 grams per ton) are considered.
The efficacy data were evaluated according to the
combination drug guidelines revised October 1983: Drugs
approved individually at a range and codified in the CFR
are not required to be titrated in the combination.
However, each drug's contribution to the combination must
be demonstrated by data from studies conducted with the
maximum approved drug level. For the NADA, data from two
treatment groups from each of the six trials are adequate
to satisfy these requirements. Treatment one (1) monensin
at 110 g/ton: Treatment two (2) monensin 110 g/ton plus
BMD at 50 g/ton.
The data for each of the above two treatments from the
six trials were pooled for analysis for weight gain and
feed efficiency. The analysis for weight gain showed no
significant difference (P = 0.10) between the two
treatments. The analysis of the feed to gain data showed
a significant difference
(P < 0.01) between the two
treatments due to BMD.
The data from the non-interference studies and the six
floor pen studies qualify the application for approval as
an aid in the prevention of coccidiosis and for improved
feed efficiency. The CVM policy outlined in the October
1983 revised guidelines permits the quantity of the range
for BMD codified in 21 CFR 558.76(e)(i), which is 4 to 50
g/ton for use in combination with monensin at 90-110
g/ton.
(Eds. note: The following table consists of 6 columns.)
SUMMARY OF RESPONSE OF BROILERS TO BACITRACIN-MD
WHEN FED WITH MONENSIN
---Coban 110 g/ton ---
---Coban 110 g/ton--- -----BMD 50 g/ton-----
No. Average Feed/ Average Feed/
Reps. Weight (lb) Gain Weight (lb) Gain
FV-B-29-74 3 3.86 2.19 3.83 2.15
FV-B-30-74 2 3.89 2.20 4.01 2.15
GA-B-53-77 3 3.82 2.22 3.85 2.18
306-572-2-7 3 3.43 2.05 3.43 2.03
306-572-2-02 3 3.70 2.06 3.83 2.05
306-572-1-14 4-6 2.93 2.05 2.99 2.00
Average 3.60 2.13 3.66 2.09
Effectiveness - Non-Interference
This submission provides additional information to the
existing Freedom of Information Summary and approval of
BMD-4-50 grams/ton and Coban 110 grams/ton: 51 FR
12/17/86, 45105. These data report an additional non-interference
study to demonstrate that the presence of
BMD at 200 grams/ton did not interfere with the
anticoccidial properties of monensin at 90 grams/ton of
feed. The experiment was conducted by Dr. K. W. Bafundo
and Dr. D. J. Donovan, Lilly Research Laboratories,
Greenfield, Indiana.
These data constitute a series of seven battery
experiments conducted to determine the compatibility of
monensin (99 ppm) and the therapeutic level of BMD (220
ppm) when fed in combination. Anticoccidial efficacy was
assessed as an aid in the prevention of infections of
Eimeria acervulina, E. maxima, E. mitis/E. mivati, E.
brunetti, E. necatrix, E. tenella, and a mixed inoculum
of the above coccidia as measured by growth performance
(weight gain and feed/gain ratios) and reduction in
mortality and lesion severity. The following seven tables
(1-7) depict the efficacy profile of the combination.
Monensin, both alone and in combination with BMD,
effectively reduced lesion scores and improved
performance. The addition of BMD to feeds had no adverse
effects on the efficacy of monensin as an aid in the
prevention of coccidial infections. Thus, BMD was found
to be compatible with monensin when the anticoccidial
efficacy of the drug was assessed.
The data in Tables 1 through 7 show that 200 grams of BMD
do not interfere with the anticoccidial activity of 90
grams/ton (99 ppm) of monensin, which supports the
conclusion that BMD at 4-50 grams/ton will not interfere
with the anticoccidial activity of monensin at 90
grams/ton (99 ppm).
(Eds. note: The following 6 tables consist of 5 columns each.)
Table 1
Experiment No. T1S8C8671
Percent Mortality, Weight Gain, Feed/Gain, and Intestinal Lesion
Scores of broiler cockerels inoculated with E. maxima.
Wt. Gain Lesion Scores
Treatment % Mort. Mean Feed/Gain Intestinal
PPM Mean grams Mean Mean
NNC
0 0.0 257.9 1.473 0.00
IC
0 0.0 226.0 1.726 4.00
Monensin
99 0.0 272.3 1.444 0.00
BMD
220 0.0 215.9 1.731 4.00
Monensin + BMD
99 + 220 0.0 287.6 1.398 0.44
NNC = Non-Infected, Non-Medicated Controls
IC = Infected Controls
Table 2
Experiment No T1S8C8672
Percent Mortality, Weight Gain, Feed/Gain, and Intestinal Lesion
Scores of broiler cockerels inoculated with E. necatrix.
Wt. Gain Lesion Scores
Treatment % Mort. Mean Feed/Gain Intestinal
PPM Mean grams Mean Mean
NNC
0 0.0 283.0 1.536 0.69
IC
0 0.0 208.3 1.743 3.75
Monensin
99 0.0 262.3 1.468 0.38
BMD
220 0.0 214.1 1.658 3.63
Monensin + BMD
99 + 220 0.0 263.0 1.494 0.35
NNC = Non-Infected, Non-Medicated Controls
IC = Infected Controls
Table 3
Experiment No. T1S8C8675
Percent Mortality, Weight Gain, Feed/Gain, and Intestinal Lesion
Scores of broiler cockerels inoculated with E. mivati/mitis.
Wt. Gain Lesion Scores
Treatment % Mort. Mean Feed/Gain Intestinal
PPM Mean grams Mean Mean
NNC
0 0.0 301.3 1.487 0.00
IC
0 0.0 255.1 1.690 2.25
Monensin
99 0.0 270.1 1.581 0.00
BMD
220 0.0 241.9 1.740 3.25
Monensin + BMD
99 + 220 0.0 269.9 1.540 0.00
NNC = Non-Infected, Non-Medicated Controls
IC = Infected Controls
Table 4
Experiment No. T1S8C8719
Percent Mortality, Weight Gain, Feed/Gain, and Intestinal Lesion
Scores of broiler cockerels inoculated with E. brunetti.
Wt. Gain Lesion Scores
Treatment % Mort. Mean Feed/Gain Intestinal
PPM Mean grams Mean Mean
NNC
0 0.0 304.8 1.587 0.63
IC
0 0.0 159.5 2.242 4.00
Monensin
99 0.0 290.3 1.630 1.88
BMD
220 0.0 137.5 2.428 3.94
Monensin + BMD
99 + 220 0.0 284.7 1.586 2.96
NNC = Non-Infected, Non-Medicated Controls
IC = Infected Controls
Table 5
Experiment No. T1S8C86D4
Percent Mortality, Weight Gain, Feed/Gain, and Intestinal Lesion
Scores of broiler cockerels inoculated with E. tenella.
Wt. Gain Lesion Scores
Treatment % Mort. Mean Feed/Gain Intestinal
PPM Mean grams Mean Mean
NNC
0 0.0 296.4 1.540 0.00
IC
0 0.0 296.4 1.505 2.44
Monensin
99 0.0 283.5 1.541 0.56
BMD
220 0.0 287.4 1.606 3.56
Monensin + BMD
99 + 220 0.0 307.5 1.452 0.81
NNC = Non-Infected, Non-Medicated Controls
IC = Infected Controls
Table 6
Experiment No. T1S8C8718
Percent Mortality, Weight Gain, Feed/Gain, and Intestinal Lesion
Scores of broiler cockerels inoculated with E. acervulina.
Wt. Gain Lesion Scores
Treatment % Mort. Mean Feed/Gain Intestinal
PPM Mean grams Mean Mean
NNC
0 0.0 300.8 1.614 0.00
IC
0 0.0 245.8 1.814 3.56
Monensin
99 0.0 300.1 1.539 0.06
BMD
220 0.0 261.0 1.680 3.38
Monensin + BMD
99 + 220 0.0 304.4 1.555 0.00
NNC = Non-Infected, Non-Medicated Controls
IC = Infected Controls
(Eds. note: The following table consists of 6 columns.)
Table 7
Experiment No. T1S8C8678
Percent Mortality, Weight Gain, Feed/Gain, and Intestinal Lesion
Scores of broiler cockerels inoculated with E. tenella,
E. acervulina, E. maxima, E. necatrix, E. brunetti and
E. mivati/mitis.
Wt. Gain Lesion Scores
Treatment % Mort. Mean Feed/Gain Intestinal Cecal
PPM Mean grams Mean Mean Mean
NNC
0 0.0 296.6 1.562 0.00 0.06
IC
0 0.0 211.6 1.866 6.75 3.44
Monensin
99 0.0 288.8 1.564 0.25 0.00
BMD
220 0.0 204.9 2.005 8.00 3.50
Monensin + BMD
99 + 220 0.0 287.1 1.559 0.00 0.25
NNC = Non-Infected, Non-Medicated Controls
IC = Infected Controls
It has been established in the original NADAs (46-592 for
bacitracin methylene disalicylate and 38-878 for
monensin) that these products are not a hazard to human
health when used according to approved labeling.
Tolerances for residues of bacitracin methylene
disalicylate are established at 0.5 ppm negligible
residue in uncooked chicken tissue (21 CFR 556.70). Safe
concentrations for total residues of monensin in chickens
are 1.5 ppm in muscle, 3.0 ppm in skin with adhering fat
and 4.5 ppm in liver (21 CFR 556.70). The tissue residue
data supporting uses of bacitracin methylene disalicylate
and monensin have been presented in the original
applications for each.
The drug residue depletion study as presented was
conducted by Elanco Products Co. Sexed, day-old Penobscot
broiler chicks were used in a 56-day study. Chicks were
allotted to pens by grab sample from each compartment of
the shipping boxes so that each pen received 50 males or
50 females. The floor pens provided 0.9 square feet per
bird.
Each pen was bedded with clean, ground corn cobs. Feed
and water was provided ad libitum . Feed was provided to
each pen in two hanging feeders. The chicks were fed
typical broiler starter and finisher rations. At 56 days
the medicated feeds were replaced with non-medicated
feeds.
Room temperature was maintained at 70° ± 5° F. Supplemental
heat was provided by thermostatically controlled infrared
heat lamps. Continuous light was provided. Ventilation
was provided by 2 attic and 4 window fans.
At termination and up to 120 hours following treatment,
birds of each sex were randomly selected and sacrificed
for each drug to be assayed at each sampling interval.
Feathers were mechanically removed. Samples of muscle,
liver, kidney and skin/fat were collected from each bird,
individually bagged and submitted for assay.
The summary of the tissue residue depletion study in
Table 8 establishes that each drug in the presence of the
other does not exceed its established safe concentration
or tolerances. In addition, one drug does not interfere
in the other's tissue residue assay. In this study
broiler chickens were fed a combination of bacitracin
methylene disalicylate (50 g/ton) and monensin (110
g/ton) for 56 days. Edible tissues as required for each
drug or combination of drugs were assayed for presence of
drug residue.
Tissue assay non-interference and method validation
studies for bacitracin assay were conducted by spiking
control chicken tissues with bacitracin zinc standard and
monensin and then assaying for bacitracin residue. The
results demonstrated no interference by monensin for
bacitracin (MO-B-TR-1-85). The recovery of bacitracin
from the spiked tissues was 84 percent.
The non-interference of bacitracin on the determination
of monensin was examined by the analysis of negative
control chicken tissues fortified with the equivalent of
5.0 and 0, and 5.0 and 0.05 ppm bacitracin zinc standard
and monensin, respectively (S-AAC-83-03). No interference
of bacitracin on the recovery of monensin was observed.
Prepared extracts of tissue fortified with the equivalent
of 5.0 ppm bacitracin gave no zone of inhibition on the
bioautographic plate. The recovery of monensin from
tissue fortified with 5.0 ppm bacitracin and 0.05 ppm
monensin was about 86 percent (0.043/0.005) which is on
the order of the expected experimental variation.
Based upon the established no withdrawal times for
monensin and bacitracin methylene disalicylate, no
residues were above tolerances in any tissues from these
broiler chickens. The data support no withdrawal for the
bacitracin methylene disalicylate/monensin combination.
(Eds. note: The following table consists of 6 columns.)
TABLE 8
RESIDUE DEPLETION ASSAY RESULTS
--Day-- --Liver-- --Kidney-- --Skin/Fat-- --Muscle--
Monensin
Estab. Safe Conc. 4.5 -- 3.0 1.5
Monensin alone 0 none none negligible negligible
+ Bacitracin-MD 0 none none negligible negligible
Bacitracin-MD
Establish Tolerance 0.5
Bacitracin-MD alone 0 none
+ Monensin 0 none
Monensin Assay Procedure
No. 5801645 for chicken tissues and eggs. Eli Lilly and Co.,
Greenfield Laboratories, Greenfield, IN.
Antibiotics Residues in Milk, Dairy Products and Animal Tissues:
Methods, Reports, Protocols. National Center for Antibiotic and Insulin Analyses.
Dept. HEW, Washington, DC 20204, Rev. October 1968. Modified Method for Determination
of Bacitracin in Tissues, Test Procedure Code 9A, A. L. Laboratories, Inc.,
Englewood Cliffs, NJ 07632.
