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Effect of Diet Composition on Chick Growth Response to Different Types and Levels of Feed Medication1,2
Effect of Diet Composition on Chick Growth Response to Different Types and Levels of Feed Medication1,2 R A U L FERNANDEZ, ERNEST L U C A S 3 AND JAMES M C G I N N I S
Department of Animal Sciences, Washington State University, Pullman, Washington 99163 (Received for publication February 22, 1973)
POULTRY SCIENCE 52: 2237-2243, 1973
INTRODUCTION
T
HE final report on the use of antibiotics in animal feeds, issued recently by a Food and Drug Administration Task Force (1972) has proposed guidelines on evaluation of claims of improvement in animal growth or feed efficiency caused by low levels of antibiotic supplements added to the diets. Even though that report and its supporting background material do recognize different circumstances that affect the growth response obtained from an antibiotic supplement, it fails to stress the importance of the diet composition as one of the main factors affecting the size of the response obtained with a given antibiotic supplement. A summary of the experiment conducted
1. Scientific Paper No. 4018. College of Agriculture, Washington State University. Project 0107. 2. Research conducted under a grant from Merck & Co., Rahway, N.J. 3. Currentaddress: Food and Drug Administration, Washington, D.C.
at the University of Wisconsin over a period of 11 years, as reported by Heth and Bird (1962), lists responses to antibiotics that ranged from 6 to 12% over the controls throughout the period. A summary by Bird (1968) on the published work on antibiotic growth response in chickens during the period 1951-1968 indicated no trend toward decreased effectiveness of bacitracin, procaine penicillin, oxytetracycline or chlortetracycline. The size of the responses listed in that review ranged from 1 to 15%, varied with the dosage level (2 to 20 p.p.m.) and with the different reports included. The conflict in results reported by different authors has stimulated investigations of the factors that influence antibiotic response. In general, the conclusion has been drawn that under stress conditions caused by the presence of unfavorable organisms, extreme temperature, disease, crowding and poor management, larger responses are obtained to antibiotics. In recent years, in our labora-
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ABSTRACT An experiment was conducted to determine the effect of the diet on the chick growth response to different antibiotics and an antimicrobial compound. The design was a factorial comprising five diets differing in their grain component, four drugs, and four levels of each drug in the diets. Each treatment had four replicate groups of 10 day-old male birds each. The replicates from each treatment were separated into two pair and placed in two contiguous animal rooms. Replicate groups within each room were placed at random. Data on body weight and feed consumption were collected up to the time the birds were three weeks of age. The results indicate that chick growth was significantly affected by diet type. Diets containing corn or wheat gave greater growth than those with barley or rye as the grain component. The drug supplements significantly affected chick growth; chicks on bacitracin or penicillin supplements had larger body weights than those on 3-nitro phenylarsonic acid. Chicks receiving phosphomycin were intermediate in body size. The level of drug used had a significant effect on growth. Responses varied and were complicated by interactions which make it necessary to specify conditions as to diet type, medication, and dosage level before being able to state that any given treatment is better. Other differences were detected in feed consumption and feed efficiency. Observations made on feces condition indicate that they were affected by diet type but not by drug supplement or dosage. An exception was the barley diet, where bacitracin, penicillin and phosphomycin improved feces condition while 3-nitro phenylarsonic acid did not.
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FERNANDEZ, LUCAS AND MCGINNIS
The study presented here was conducted to investigate the effect of changing the grain component of a broiler diet on the chick growth response to three different antibiotics and one antimicrobial compound. The growth promoting effect of different dosage levels of each drug was also studied.
PROCEDURE Day-old commercially obtained White Rock males were randomly distributed in groups of 10 birds each. The groups were then randomly distributed to the different treatments. The birds were maintained in electrically heated battery brooders with
TABLE 1.—Experimental design
raised screen floors. Feed and water were provided ad libitum and 14 hours of light were given daily. The chicks were groupweighed at weekly intervals for a 3-week period and feed consumption by each group was determined at the time of weighing. The design of the experiment was a factorial consisting of five diets, four drug supplements and four levels of each supplement (including the zero level). Each treatment was replicated four times and half of the replicates were put in each of two contiguous animal rooms. The groups within each room were randomly distributed in the battery brooders. Table 1 presents the experimental design. The drugs were compounded into premixes at varying concentrations and the premixes were added as 1% supplements to the complete diet. Table 2 presents the composition of the basal diet. The control diet is a commercial unmedicated corn-soy type chick starter. Feces condition was evaluated at the time the birds were three weeks of age by the subjective scoring by two trained individuals as to the amount of feces that were adhering to the wire screen floors. Each group was assigned a value that was the average of the two individual observations. Data on body weight, feed consumption, feed efficiency and scoring of feces condition when the birds were 3 weeks of age were submitted to analysis of variance according to the procedures outlined by Steel and Torrie (1960). The data were submitted to further statistical analysis that varied, but in all
and levels of medication used1 Level
Diets Medication used Control or MD Bacitracin experimental diets Procaine penicillin Phosphomycin 3-nitro phenylarsonic acid 'Levels given indicate p.p.m. in the diets.
Zero
Low
Medium
High
0
5
15
25
0 0
7 7
28 49
49 98
0
5
25
50
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tories at Washington State University, we have become increasingly aware of the importance of diet composition on the size of the growth response obtained from antibiotic supplements to the diet. A report by MacAuliffe and McGinnis (1971) showed antibiotic growth responses as high as 35% over the control obtained with diets containing a high level of rye but otherwise nutritionally adequate. Goatcher and McGinnis (1972) reported that chick growth was markedly depressed by feeding diets containing high levels of dry beans (Phaseolus vulgaris), lentils (Lens esculenta), or dry field peas (Pisum sativum), and that antibiotic supplements counteracted these growth depressing effects to a considerable degree. They obtained growth responses as high as 75% over the unsupplemented control diets.
DIET AND FEED MEDICATION
TABLE 2.—Composition of the basal diet Percent 55.0 27.0 5.0 5.0 1.0 1.25 0.23 4.0 0.5 0.67 0.25 0.05 0.05 100.00 'The grain component was either corn, wheat, rye or barley. 2 The vitamin premix supplied the following per kg. of diet: vitamin A, 5,500 I.U.; vitamin D3, 1,6501.C.U.; riboflavin, 3.3 mg.; Ca pantothenate, 3.3 mg.; niacin, 17.6 mg.; ethoxyquin, 125 mg.; vitamin B12, 0.01 mg. 3 Trace mineral mix supplied the following per kg. of diet: Mn, 500 mg.; Fe, 50 mg.; Cu, 5 mg.; Ca, 60 mg.; Zn, 50 mg.; I, 1.5 mg.; and Co, 0.5 mg.
instances it was done according to the procedures outlined by the above cited authors. RESULTS AND DISCUSSION The means for the main effect of diet as presented in Table 3 are the average effects over all factors of the experiment and while significant differences among diets were observed, caution should be used in interpreting the data presented there, because the effect of different interactions are included in the overall data. The data on effect of diet and dosage level of medication used (Table 4) further substantiates that the diet had a significant effect on chick growth. Chicks grew equally well on the control, the corn, and the wheat diets. Chicks fed the barley diets grew significantly slower than those fed the previously mentioned diets, and chicks fed the rye diets had growth significantly lower
TABLE 3.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for the main effect of diet.' Feed Gain Body wt consumed Diet feed gg0.686a 590b 405a Control 0.694a 598b 414a Corn 0.668b 621a 414a Wheat 0.613d 547c 335c Rye 0.646c 585b 377b Barley 'The data for each column was subjected to Duncan's new multiple range test. Means within a column having the same superscript do not differ significantly (P = 0.05 or less).
than chicks on the barley diets. In regard to feed consumption, chicks fed wheat diets ate significantly more feed than did those on the other diets. Chicks on the control or barley diets did not differ significantly in feed consumption, but chicks fed rye diets ate significantly less than those fed any other diet. Chicks fed the control and corn diets had significantly better feed efficiency than those on the wheat diet, but in turn, chicks on wheat diets had significantly better feed efficiency than those on rye or barley diets. This was due to the fact that chicks on wheat diets grew as well as those on the control or corn diets but used more feed to achieve the same results. Chicks on rye diets had significantly poorer feed efficiency than those chicks receiving the barley diet. Data presented in Tables 3 and 4 agree with previously published data by Fry et al. (1958), MacAuliffe and McGinnis (1971), Moran et al. (1969) and others on one or more of the multiple comparisons involved in those tables. An anlysis of data in Table 4 substantiates the assertion that type of diet has a significant effect on size of growth response obtained to a particular drug at a given dosage. If a comparison is made between zero dosage level in each diet and the largest growth response obtained to any dosage level within that diet, it is found that on a percentage basis the maximal growth responses obtained
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Ingredient Grain component' Soybean meal, dehulled Herring fish meal Meat and bone meal Dried whey product Dehydrated alfalfa Iodized salt Animal fat Dicalcium phosphate Limestone Vitamin premix2 Trace mineral premix3 DL-methionine
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FERNANDEZ, LUCAS AND MCGINNIS
TABLE 4.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for diet and dosage level effect' Diet Control
Corn
Rye
Barley
Zero Low Medium High Zero Low Medium High Zero Low Medium High Zero Low Medium High Zero Low Medium High
Body wt. g389 405 408 418 396 424 421 416 405 420 414 419 306 326 344 365 367 377 381 383
Feed consumed, g. 575 600 588 598 587 605 596 605 608 640 624 614 510 533 558 588 570 584 589 599
Feed/gain 0.676 0.676 0.695 0.699 0.675 0.702 0.711 0.689 0.669 0.658 0.664 0.682 0.606 0.611 0.616 0.619 0.645 0.648 0.649 0.641
'The data for each of the three parameters was subjected to Tukey's test and at P = 0.05 or less: B.W., 30; F.C., 50; G/F, 0.046. Means which differ by more than the stated values are significantly different. were: control, 7; corn, 7; wheat, 4; rye, 19; and barley, 4. Furthermore, it should be noted that maximal growth response was not obtained at the same dosage level with all diets, indicating that diet had an effect on determining the most effective dosage level. Table 5 presents the means for the main effects of drug types used. The data presented indicate there was no difference in growth of chicks fed MD bacitracin, procaine penicillin or phosphomycin. Chicks fed 3-nitro phenylarsonic acid had significantly lower growth than those fed MD bacitracin or procaine penicillin, but not different from those fed phosphomycin. Although data on the main effect of the drug supplements (Table 5) show no significant differences for feed consumption, data on interaction between drug type and dosage level (Table 6) indicated significant differences between some of the means. The data in Table 6 indicate that feed consumption varied widely according to both drug type and dosage level, and further that there was a difference in
direction as well as magnitude of response. Before making any conclusion as to the effect of antibiotic on feed consumption, the dosage level must be considered. Data in Table 5 also indicate there was no significant difference in feed efficiency of chicks fed either MD bacitracin, procaine penicillin or phosphomycin. Chicks fed 3-nitro phenylarsonic acid had a significantly lower feed efficiency than those fed MD bacitracin, but not dif-
TABLE 5.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for the main effects of drug type.' Body Feed conGain wt. sumed feed gg0.669a 394a 598a 0.664ab 393a 593a 0.658ab 387ab 488a
Drug type MD bacitracin Procaine penicillin Phosphomycin 3-nitro phenylarsonic acid 584a 0.655b 382b 'The data for each of the three parameters was submitted to Duncan's new multiple range test. Means within a column having the same superscript do not differ significantly (P = 0.05 or less).
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Wheat
Dosage level
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DIET AND FEED MEDICATION
TABLE 6.—Summary of mean chick body weight, feed consumed and feed efficiency at three weeks of age for drug type and dosage level effect' Body wt. g-
MD bacitracin
0 5 15 25
367 395 407 409
Procaine penicillin
0 7 28 49
Phosphomycin
3-nitro phenylarsonic acid arsonic acid
Drug type
Feed consumed g-
Gain/feed
555 595 604 602
0.662 0.663 0.673 0.680
375 400 391 407
571 611 580 610
0.656 0.655 0.677 0.668
0 7 49 98
376 383 392 396
578 578 588 607
0.653 0.661 0.665 0.653
0 5 25 50
372 384 385 388
576 586 590 585
0.646 0.655 0.653 0.664
'The data for each of the three parameters was submitted to Tukey's test and at P = 0.05 or less: B.W., 26; F.C., 43; G/F, 0.040. Means which differ by more than the stated values are significantly different.
TABLE 7.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for diet and drug type effect'
Control
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
Body wt. g417 404 402 397
Corn
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
413 423 416 405
593 597 602 601
0.697 0.711 0.692 0.676
Wheat
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
413 417 414 413
600 641 620 624
0.690 0.651 0.668 0.663
Rye
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
343 351 323 325
558 555 539 538
0.615 0.633 0.604 0.604
Barley
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
386 371 379 373
594 580 592 576
0.650 0.642 0.642 0.649
Diet
Drug type
Feed consumed g599 592 586 584
0.696 0.684 0.686 0.680
Gain feed
'The data for each of the three parameters was submitted to Tukey's test and at P = 0.05 or less: B.W., 30; F.C., 50; G/F, 0.046. Means which differ by more than the stated values are significantly different.
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Dosage level, p.p.m.
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FERNANDEZ, LUCAS AND MCGINNIS
TABLE 8.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for the main effect of drug dosage level'
ferent than the chicks consuming either procaine penicillin or phosphomycin. It is difficult to compare the data presented in Tables 5 and 6 with data published elsewhere, because the effectiveness of a given drug type as a growth promoting agent is clearly affected by the dosage level. The four drugs used in this study were included at
TABLE 9.—Effect
of diet, drug type and dosage level on feces condition of three week old chicks' Dosage level
Diet Control
Corn
Wheat
Rye
Barley
Drug type
Zero
Low
Medium
High
MD bacitracin Proc. penicillin Phosphomycin 3-nitro MD bacitracin Proc. penicillin Phosphomycin 3-nitro MD bacitracin Proc. penicillin Phosphomycin 3-nitro MD bacitracin Proc. penicillin Phosphomycin 3-nitro MD bacitracin Proc. penicillin Phosphomycin 3-nitro
1.0 1.0 1.1 1.1 1.1 1.0 1.0 1.3 2.3 2.1 2.1 1.9 3.6 3.6 3.5 3.5 3.0 3.3 3.3 2.9
1.0 1.0 1.0 1.0 1.0 1.3 1.3 1.0 1.8 2.0 1.8 1.9 3.3 3.6 3.6 3.5 1.9 2.4 2.6 2.6
1.0 1.0 1.0 1.0 1.3 1.1 1.0 1.0 2.0 2.1 1.8 1.8 3.8 3.8 3.8 3.8 1.6 2.6 2.4 3.1
1.1 1.1 1.0 1.3 1.1 1.0 1.0 1.0 1.9 1.8 1.8 1.9 3.5 3.9 3.6 3.8 1.6 2.6 2.8 2.9
'Feces condition was measured by an arbitrary visual observation of the amount of feces adhered to the wire floor screen. Scoring system as used denotes the following: 1 = clean; 2 = light; 3 = moderate; and 4 = heavy. Each of the means presented in this table is the average of 8 individual observations. 2 The data was statistically analyzed and a least significant difference value was calculated. LSD (0.05) = 0.43. Means that differ by more than the stated value are significantly different.
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Drug Feed Gain dosage Body wt. consumed level feed 8gZero 373c 570b 0.654b Low 390b 592a 0.659ab Medium 394ab 591a 0.667a High 400a 601a 0.666ab 'The data for each of the three parameters was submitted to Duncan's new multiple range test. Means within a column having the same superscript do not differ significantly (P = 0.05 or less).
different levels, but within a range for each drug that had previously been established as most effective. A summary of the two factor means for diet and drug type effects is presented in Table 7. The data as compared using the Tukey's test show a number of significant differences, but comparison of means within a single diet shows no advantage for any particular drug. There is, however, a slight indication that 3-nitro phenylarsonic acid was less effective than MD bacitracin or procaine penicillin. Again the effectiveness of any given drug was related to the range of dosage at which the drug was used. A summary of the means for the main effect of drug dosage level is presented in Table 8. As discussed before in regard to the data in Tables 3 and 4, there were significant interactions between diet type and dosage level, and the two factor data presented in Table 4 should be studied carefully before
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DIET AND FEED MEDICATION
OCTOBER 17-19.
biotics significantly reduced the adherence feces to the floors, while the antimicrobial compound did not. The dosage level had no effect on feces condition. REFERENCES Bird.H.R., 1968. Effectiveness of antibiotics in broiler feeds. World Poultry Sci. J. 24: 309-312. Burnett, G. S., 1966. Studies of viscosity as the probable factor involved in the improvement of certain barleys for chickens by enzyme supplementation. British Poultry Sci. 7: 35-75. FDA Task Force, 1972. The use of antibiotics in animal feeds. A Report Submitted to the Commissioner of the Food and Drug Administration, Rockville, Maryland. Fry, R. E., J. B. Allred, L. S. Jensen and J. McGinnis, 1958. Influence of enzyme supplementation and water treatment on the nutritive value of different grains for poults. Poultry Sci. 37: 372-375. Goatcher, W. D., and J. McGinnis, 1972. Influence of beans, peas and lentils as dietary ingredients on the growth response of chicks to antibiotic and methionine supplementation of the diet. Poultry Sci. 51:440-443. Halpin, J. G., C. E. Holmes and E. B. Hart, 1936. Rye as a feed for poultry. Poultry Sci. 15: 3-8. Heth, D. A., and H. R. Bird, 1962. Growth response of chicks to antibiotics from 1950 to 1961. Poultry Sci. 41:755-760. MacAuliffe, T., and J. McGinnis, 1971. Effect of antibiotic supplements to diets containing rye on chick growth. Poultry Sci. 50: 1130-1134. Moran, E. T., S. P. Lall and J. E. Summers, 1969. The feeding value of rye for chicks: effect of enzyme supplements, antibiotics, autoclaving and geographical area of production. Poultry Sci. 48: 939-949. Preece, I. A., and K. MacKenzie, 1952. Non-starchy polysaccharides of cereal grains. II. Distribution of water-soluble gum-like materials in cereals. J. Inst. Brew. 58: 459-464. Steel, G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., New York, N.Y. Willingham, H. E., L. S. Jensen and J. McGinnis, 1959. Studies on the role of enzyme supplementation and water treatment for improving the nutritional value of barley. Poultry Sci. 38: 539-544.
19TH ANNUAL CONFERENCE, NATIONAL BROILER COUNCIL, MAYFLOWER HOTEL, WASHINGTON, D.C.
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making any inferences from the main effects since diet type markedly influenced the response to any given level of drug. The data in Table 8 indicate that the zero dosage level gave the lowest chick body weight. Chick growth was significantly improved by the low level of supplementation, but there was no difference in chick body weight between the low and medium levels. Chicks fed the high level of supplementation had significantly greater body weight than those fed the low level, but there was no difference between the high and medium levels. Feed consumption by chicks receiving zero dosage level was significantly lower than for those receiving the other dosage levels. Feed efficiency of chicks on zero dosage level was significantly different from that of chicks on medium level, but not different from that of chicks on low or high dosage levels. A measure of chick feces condition as determined by an arbitrary scoring system is presented in Table 9. The overall data indicate that feces condition was affected mainly by the basal diet. Chicks receiving the control or corn diets had little or no feces adhering to the wire floor screens, while chicks on the wheat, rye and barley diets exhibited light, heavy, and moderate adherence of feces to the screen floors, respectively. The fecal problems associated with the use of rye and barley diets has previously been reported by several authors (Preece and McKenzie, 1952; Willingham et al., 1959; Halpin et al, 1936; and Burnett, 1966) but a light condition induced by a high level of wheat in the diet seemed to have not attracted much attention. Data in Table 9 indicate that the drug type used had no effect on feces conditions except for chicks receiving the barley containing diets where the three anti-
Department of Animal Sciences, Washington State University, Pullman, Washington 99163 (Received for publication February 22, 1973)
POULTRY SCIENCE 52: 2237-2243, 1973
INTRODUCTION
T
HE final report on the use of antibiotics in animal feeds, issued recently by a Food and Drug Administration Task Force (1972) has proposed guidelines on evaluation of claims of improvement in animal growth or feed efficiency caused by low levels of antibiotic supplements added to the diets. Even though that report and its supporting background material do recognize different circumstances that affect the growth response obtained from an antibiotic supplement, it fails to stress the importance of the diet composition as one of the main factors affecting the size of the response obtained with a given antibiotic supplement. A summary of the experiment conducted
1. Scientific Paper No. 4018. College of Agriculture, Washington State University. Project 0107. 2. Research conducted under a grant from Merck & Co., Rahway, N.J. 3. Currentaddress: Food and Drug Administration, Washington, D.C.
at the University of Wisconsin over a period of 11 years, as reported by Heth and Bird (1962), lists responses to antibiotics that ranged from 6 to 12% over the controls throughout the period. A summary by Bird (1968) on the published work on antibiotic growth response in chickens during the period 1951-1968 indicated no trend toward decreased effectiveness of bacitracin, procaine penicillin, oxytetracycline or chlortetracycline. The size of the responses listed in that review ranged from 1 to 15%, varied with the dosage level (2 to 20 p.p.m.) and with the different reports included. The conflict in results reported by different authors has stimulated investigations of the factors that influence antibiotic response. In general, the conclusion has been drawn that under stress conditions caused by the presence of unfavorable organisms, extreme temperature, disease, crowding and poor management, larger responses are obtained to antibiotics. In recent years, in our labora-
2237
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ABSTRACT An experiment was conducted to determine the effect of the diet on the chick growth response to different antibiotics and an antimicrobial compound. The design was a factorial comprising five diets differing in their grain component, four drugs, and four levels of each drug in the diets. Each treatment had four replicate groups of 10 day-old male birds each. The replicates from each treatment were separated into two pair and placed in two contiguous animal rooms. Replicate groups within each room were placed at random. Data on body weight and feed consumption were collected up to the time the birds were three weeks of age. The results indicate that chick growth was significantly affected by diet type. Diets containing corn or wheat gave greater growth than those with barley or rye as the grain component. The drug supplements significantly affected chick growth; chicks on bacitracin or penicillin supplements had larger body weights than those on 3-nitro phenylarsonic acid. Chicks receiving phosphomycin were intermediate in body size. The level of drug used had a significant effect on growth. Responses varied and were complicated by interactions which make it necessary to specify conditions as to diet type, medication, and dosage level before being able to state that any given treatment is better. Other differences were detected in feed consumption and feed efficiency. Observations made on feces condition indicate that they were affected by diet type but not by drug supplement or dosage. An exception was the barley diet, where bacitracin, penicillin and phosphomycin improved feces condition while 3-nitro phenylarsonic acid did not.
2238
FERNANDEZ, LUCAS AND MCGINNIS
The study presented here was conducted to investigate the effect of changing the grain component of a broiler diet on the chick growth response to three different antibiotics and one antimicrobial compound. The growth promoting effect of different dosage levels of each drug was also studied.
PROCEDURE Day-old commercially obtained White Rock males were randomly distributed in groups of 10 birds each. The groups were then randomly distributed to the different treatments. The birds were maintained in electrically heated battery brooders with
TABLE 1.—Experimental design
raised screen floors. Feed and water were provided ad libitum and 14 hours of light were given daily. The chicks were groupweighed at weekly intervals for a 3-week period and feed consumption by each group was determined at the time of weighing. The design of the experiment was a factorial consisting of five diets, four drug supplements and four levels of each supplement (including the zero level). Each treatment was replicated four times and half of the replicates were put in each of two contiguous animal rooms. The groups within each room were randomly distributed in the battery brooders. Table 1 presents the experimental design. The drugs were compounded into premixes at varying concentrations and the premixes were added as 1% supplements to the complete diet. Table 2 presents the composition of the basal diet. The control diet is a commercial unmedicated corn-soy type chick starter. Feces condition was evaluated at the time the birds were three weeks of age by the subjective scoring by two trained individuals as to the amount of feces that were adhering to the wire screen floors. Each group was assigned a value that was the average of the two individual observations. Data on body weight, feed consumption, feed efficiency and scoring of feces condition when the birds were 3 weeks of age were submitted to analysis of variance according to the procedures outlined by Steel and Torrie (1960). The data were submitted to further statistical analysis that varied, but in all
and levels of medication used1 Level
Diets Medication used Control or MD Bacitracin experimental diets Procaine penicillin Phosphomycin 3-nitro phenylarsonic acid 'Levels given indicate p.p.m. in the diets.
Zero
Low
Medium
High
0
5
15
25
0 0
7 7
28 49
49 98
0
5
25
50
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tories at Washington State University, we have become increasingly aware of the importance of diet composition on the size of the growth response obtained from antibiotic supplements to the diet. A report by MacAuliffe and McGinnis (1971) showed antibiotic growth responses as high as 35% over the control obtained with diets containing a high level of rye but otherwise nutritionally adequate. Goatcher and McGinnis (1972) reported that chick growth was markedly depressed by feeding diets containing high levels of dry beans (Phaseolus vulgaris), lentils (Lens esculenta), or dry field peas (Pisum sativum), and that antibiotic supplements counteracted these growth depressing effects to a considerable degree. They obtained growth responses as high as 75% over the unsupplemented control diets.
DIET AND FEED MEDICATION
TABLE 2.—Composition of the basal diet Percent 55.0 27.0 5.0 5.0 1.0 1.25 0.23 4.0 0.5 0.67 0.25 0.05 0.05 100.00 'The grain component was either corn, wheat, rye or barley. 2 The vitamin premix supplied the following per kg. of diet: vitamin A, 5,500 I.U.; vitamin D3, 1,6501.C.U.; riboflavin, 3.3 mg.; Ca pantothenate, 3.3 mg.; niacin, 17.6 mg.; ethoxyquin, 125 mg.; vitamin B12, 0.01 mg. 3 Trace mineral mix supplied the following per kg. of diet: Mn, 500 mg.; Fe, 50 mg.; Cu, 5 mg.; Ca, 60 mg.; Zn, 50 mg.; I, 1.5 mg.; and Co, 0.5 mg.
instances it was done according to the procedures outlined by the above cited authors. RESULTS AND DISCUSSION The means for the main effect of diet as presented in Table 3 are the average effects over all factors of the experiment and while significant differences among diets were observed, caution should be used in interpreting the data presented there, because the effect of different interactions are included in the overall data. The data on effect of diet and dosage level of medication used (Table 4) further substantiates that the diet had a significant effect on chick growth. Chicks grew equally well on the control, the corn, and the wheat diets. Chicks fed the barley diets grew significantly slower than those fed the previously mentioned diets, and chicks fed the rye diets had growth significantly lower
TABLE 3.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for the main effect of diet.' Feed Gain Body wt consumed Diet feed gg0.686a 590b 405a Control 0.694a 598b 414a Corn 0.668b 621a 414a Wheat 0.613d 547c 335c Rye 0.646c 585b 377b Barley 'The data for each column was subjected to Duncan's new multiple range test. Means within a column having the same superscript do not differ significantly (P = 0.05 or less).
than chicks on the barley diets. In regard to feed consumption, chicks fed wheat diets ate significantly more feed than did those on the other diets. Chicks on the control or barley diets did not differ significantly in feed consumption, but chicks fed rye diets ate significantly less than those fed any other diet. Chicks fed the control and corn diets had significantly better feed efficiency than those on the wheat diet, but in turn, chicks on wheat diets had significantly better feed efficiency than those on rye or barley diets. This was due to the fact that chicks on wheat diets grew as well as those on the control or corn diets but used more feed to achieve the same results. Chicks on rye diets had significantly poorer feed efficiency than those chicks receiving the barley diet. Data presented in Tables 3 and 4 agree with previously published data by Fry et al. (1958), MacAuliffe and McGinnis (1971), Moran et al. (1969) and others on one or more of the multiple comparisons involved in those tables. An anlysis of data in Table 4 substantiates the assertion that type of diet has a significant effect on size of growth response obtained to a particular drug at a given dosage. If a comparison is made between zero dosage level in each diet and the largest growth response obtained to any dosage level within that diet, it is found that on a percentage basis the maximal growth responses obtained
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Ingredient Grain component' Soybean meal, dehulled Herring fish meal Meat and bone meal Dried whey product Dehydrated alfalfa Iodized salt Animal fat Dicalcium phosphate Limestone Vitamin premix2 Trace mineral premix3 DL-methionine
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TABLE 4.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for diet and dosage level effect' Diet Control
Corn
Rye
Barley
Zero Low Medium High Zero Low Medium High Zero Low Medium High Zero Low Medium High Zero Low Medium High
Body wt. g389 405 408 418 396 424 421 416 405 420 414 419 306 326 344 365 367 377 381 383
Feed consumed, g. 575 600 588 598 587 605 596 605 608 640 624 614 510 533 558 588 570 584 589 599
Feed/gain 0.676 0.676 0.695 0.699 0.675 0.702 0.711 0.689 0.669 0.658 0.664 0.682 0.606 0.611 0.616 0.619 0.645 0.648 0.649 0.641
'The data for each of the three parameters was subjected to Tukey's test and at P = 0.05 or less: B.W., 30; F.C., 50; G/F, 0.046. Means which differ by more than the stated values are significantly different. were: control, 7; corn, 7; wheat, 4; rye, 19; and barley, 4. Furthermore, it should be noted that maximal growth response was not obtained at the same dosage level with all diets, indicating that diet had an effect on determining the most effective dosage level. Table 5 presents the means for the main effects of drug types used. The data presented indicate there was no difference in growth of chicks fed MD bacitracin, procaine penicillin or phosphomycin. Chicks fed 3-nitro phenylarsonic acid had significantly lower growth than those fed MD bacitracin or procaine penicillin, but not different from those fed phosphomycin. Although data on the main effect of the drug supplements (Table 5) show no significant differences for feed consumption, data on interaction between drug type and dosage level (Table 6) indicated significant differences between some of the means. The data in Table 6 indicate that feed consumption varied widely according to both drug type and dosage level, and further that there was a difference in
direction as well as magnitude of response. Before making any conclusion as to the effect of antibiotic on feed consumption, the dosage level must be considered. Data in Table 5 also indicate there was no significant difference in feed efficiency of chicks fed either MD bacitracin, procaine penicillin or phosphomycin. Chicks fed 3-nitro phenylarsonic acid had a significantly lower feed efficiency than those fed MD bacitracin, but not dif-
TABLE 5.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for the main effects of drug type.' Body Feed conGain wt. sumed feed gg0.669a 394a 598a 0.664ab 393a 593a 0.658ab 387ab 488a
Drug type MD bacitracin Procaine penicillin Phosphomycin 3-nitro phenylarsonic acid 584a 0.655b 382b 'The data for each of the three parameters was submitted to Duncan's new multiple range test. Means within a column having the same superscript do not differ significantly (P = 0.05 or less).
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Wheat
Dosage level
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TABLE 6.—Summary of mean chick body weight, feed consumed and feed efficiency at three weeks of age for drug type and dosage level effect' Body wt. g-
MD bacitracin
0 5 15 25
367 395 407 409
Procaine penicillin
0 7 28 49
Phosphomycin
3-nitro phenylarsonic acid arsonic acid
Drug type
Feed consumed g-
Gain/feed
555 595 604 602
0.662 0.663 0.673 0.680
375 400 391 407
571 611 580 610
0.656 0.655 0.677 0.668
0 7 49 98
376 383 392 396
578 578 588 607
0.653 0.661 0.665 0.653
0 5 25 50
372 384 385 388
576 586 590 585
0.646 0.655 0.653 0.664
'The data for each of the three parameters was submitted to Tukey's test and at P = 0.05 or less: B.W., 26; F.C., 43; G/F, 0.040. Means which differ by more than the stated values are significantly different.
TABLE 7.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for diet and drug type effect'
Control
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
Body wt. g417 404 402 397
Corn
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
413 423 416 405
593 597 602 601
0.697 0.711 0.692 0.676
Wheat
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
413 417 414 413
600 641 620 624
0.690 0.651 0.668 0.663
Rye
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
343 351 323 325
558 555 539 538
0.615 0.633 0.604 0.604
Barley
MD bacitracin Proc. penicillin Phosphomycin 3-nitro
386 371 379 373
594 580 592 576
0.650 0.642 0.642 0.649
Diet
Drug type
Feed consumed g599 592 586 584
0.696 0.684 0.686 0.680
Gain feed
'The data for each of the three parameters was submitted to Tukey's test and at P = 0.05 or less: B.W., 30; F.C., 50; G/F, 0.046. Means which differ by more than the stated values are significantly different.
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Dosage level, p.p.m.
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TABLE 8.—Summary of mean chick body weight, feed consumption and feed efficiency at three weeks of age for the main effect of drug dosage level'
ferent than the chicks consuming either procaine penicillin or phosphomycin. It is difficult to compare the data presented in Tables 5 and 6 with data published elsewhere, because the effectiveness of a given drug type as a growth promoting agent is clearly affected by the dosage level. The four drugs used in this study were included at
TABLE 9.—Effect
of diet, drug type and dosage level on feces condition of three week old chicks' Dosage level
Diet Control
Corn
Wheat
Rye
Barley
Drug type
Zero
Low
Medium
High
MD bacitracin Proc. penicillin Phosphomycin 3-nitro MD bacitracin Proc. penicillin Phosphomycin 3-nitro MD bacitracin Proc. penicillin Phosphomycin 3-nitro MD bacitracin Proc. penicillin Phosphomycin 3-nitro MD bacitracin Proc. penicillin Phosphomycin 3-nitro
1.0 1.0 1.1 1.1 1.1 1.0 1.0 1.3 2.3 2.1 2.1 1.9 3.6 3.6 3.5 3.5 3.0 3.3 3.3 2.9
1.0 1.0 1.0 1.0 1.0 1.3 1.3 1.0 1.8 2.0 1.8 1.9 3.3 3.6 3.6 3.5 1.9 2.4 2.6 2.6
1.0 1.0 1.0 1.0 1.3 1.1 1.0 1.0 2.0 2.1 1.8 1.8 3.8 3.8 3.8 3.8 1.6 2.6 2.4 3.1
1.1 1.1 1.0 1.3 1.1 1.0 1.0 1.0 1.9 1.8 1.8 1.9 3.5 3.9 3.6 3.8 1.6 2.6 2.8 2.9
'Feces condition was measured by an arbitrary visual observation of the amount of feces adhered to the wire floor screen. Scoring system as used denotes the following: 1 = clean; 2 = light; 3 = moderate; and 4 = heavy. Each of the means presented in this table is the average of 8 individual observations. 2 The data was statistically analyzed and a least significant difference value was calculated. LSD (0.05) = 0.43. Means that differ by more than the stated value are significantly different.
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Drug Feed Gain dosage Body wt. consumed level feed 8gZero 373c 570b 0.654b Low 390b 592a 0.659ab Medium 394ab 591a 0.667a High 400a 601a 0.666ab 'The data for each of the three parameters was submitted to Duncan's new multiple range test. Means within a column having the same superscript do not differ significantly (P = 0.05 or less).
different levels, but within a range for each drug that had previously been established as most effective. A summary of the two factor means for diet and drug type effects is presented in Table 7. The data as compared using the Tukey's test show a number of significant differences, but comparison of means within a single diet shows no advantage for any particular drug. There is, however, a slight indication that 3-nitro phenylarsonic acid was less effective than MD bacitracin or procaine penicillin. Again the effectiveness of any given drug was related to the range of dosage at which the drug was used. A summary of the means for the main effect of drug dosage level is presented in Table 8. As discussed before in regard to the data in Tables 3 and 4, there were significant interactions between diet type and dosage level, and the two factor data presented in Table 4 should be studied carefully before
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DIET AND FEED MEDICATION
OCTOBER 17-19.
biotics significantly reduced the adherence feces to the floors, while the antimicrobial compound did not. The dosage level had no effect on feces condition. REFERENCES Bird.H.R., 1968. Effectiveness of antibiotics in broiler feeds. World Poultry Sci. J. 24: 309-312. Burnett, G. S., 1966. Studies of viscosity as the probable factor involved in the improvement of certain barleys for chickens by enzyme supplementation. British Poultry Sci. 7: 35-75. FDA Task Force, 1972. The use of antibiotics in animal feeds. A Report Submitted to the Commissioner of the Food and Drug Administration, Rockville, Maryland. Fry, R. E., J. B. Allred, L. S. Jensen and J. McGinnis, 1958. Influence of enzyme supplementation and water treatment on the nutritive value of different grains for poults. Poultry Sci. 37: 372-375. Goatcher, W. D., and J. McGinnis, 1972. Influence of beans, peas and lentils as dietary ingredients on the growth response of chicks to antibiotic and methionine supplementation of the diet. Poultry Sci. 51:440-443. Halpin, J. G., C. E. Holmes and E. B. Hart, 1936. Rye as a feed for poultry. Poultry Sci. 15: 3-8. Heth, D. A., and H. R. Bird, 1962. Growth response of chicks to antibiotics from 1950 to 1961. Poultry Sci. 41:755-760. MacAuliffe, T., and J. McGinnis, 1971. Effect of antibiotic supplements to diets containing rye on chick growth. Poultry Sci. 50: 1130-1134. Moran, E. T., S. P. Lall and J. E. Summers, 1969. The feeding value of rye for chicks: effect of enzyme supplements, antibiotics, autoclaving and geographical area of production. Poultry Sci. 48: 939-949. Preece, I. A., and K. MacKenzie, 1952. Non-starchy polysaccharides of cereal grains. II. Distribution of water-soluble gum-like materials in cereals. J. Inst. Brew. 58: 459-464. Steel, G. D., and J. H. Torrie, 1960. Principles and Procedures of Statistics. McGraw-Hill Book Co., New York, N.Y. Willingham, H. E., L. S. Jensen and J. McGinnis, 1959. Studies on the role of enzyme supplementation and water treatment for improving the nutritional value of barley. Poultry Sci. 38: 539-544.
19TH ANNUAL CONFERENCE, NATIONAL BROILER COUNCIL, MAYFLOWER HOTEL, WASHINGTON, D.C.
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making any inferences from the main effects since diet type markedly influenced the response to any given level of drug. The data in Table 8 indicate that the zero dosage level gave the lowest chick body weight. Chick growth was significantly improved by the low level of supplementation, but there was no difference in chick body weight between the low and medium levels. Chicks fed the high level of supplementation had significantly greater body weight than those fed the low level, but there was no difference between the high and medium levels. Feed consumption by chicks receiving zero dosage level was significantly lower than for those receiving the other dosage levels. Feed efficiency of chicks on zero dosage level was significantly different from that of chicks on medium level, but not different from that of chicks on low or high dosage levels. A measure of chick feces condition as determined by an arbitrary scoring system is presented in Table 9. The overall data indicate that feces condition was affected mainly by the basal diet. Chicks receiving the control or corn diets had little or no feces adhering to the wire floor screens, while chicks on the wheat, rye and barley diets exhibited light, heavy, and moderate adherence of feces to the screen floors, respectively. The fecal problems associated with the use of rye and barley diets has previously been reported by several authors (Preece and McKenzie, 1952; Willingham et al., 1959; Halpin et al, 1936; and Burnett, 1966) but a light condition induced by a high level of wheat in the diet seemed to have not attracted much attention. Data in Table 9 indicate that the drug type used had no effect on feces conditions except for chicks receiving the barley containing diets where the three anti-