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Factors Affecting the Response of Chicks and Poults to Feed Pelleting1
Factors Affecting the Response of Chicks and Poults to Feed Pelleting1 JOHN B. ALLRED, LEO S. JENSEN AND JAMES MCGINNIS
Department of Poultry Science, State College of Washington, Pullman, Washington (Received for publication November 13, 1956)
Research with turkey poults has demonstrated that increased growth and feed efficiency result when rations are pelleted. Ziegenhagen et al. (1947) reported a significant increase in growth of turkey poults when mash rations were fed in the form of pellets or granules. 1 Scientific Paper No. 1545, Washington Agricultural Experiment Stations, Project 1304.
Efficiency of feed utilization was also improved. Dymsza et al. (1955), using rations containing 5, 10, and 15% fiber, showed that pelleting and subsequent crumbling concentrated the nutrients and counteracted some of the adverse effects of low energy diets when fed to poults. Many reports on the use of animal tallow in poultry rations have appeared recently (Aitken et al., 1954; Biely and March, 1954; Waibel 1955; and others). Most of the reports showed that feed efficiency increased when animal tallow was added to the ration. In some cases, increased growth rate was also observed. The experiments reported herein were undertaken to study further the effect of pelleting feeds upon the performance of chicks and poults and to determine the effect of animal tallow and protein level in relation to the response obtained by pelleting. PROCEDURE AND RESULTS
In the following series of experiments all of the turkey poults and chicks were housed in electrically-heated, wire-floored battery brooders. The birds received food and water ad libitum during the experimental period. Group body weights and feed consumption data were obtained at weekly intervals. The experiments were terminated at the end of 4 weeks. The pelleted feeds used in these experiments were made with a California pellet mill, using either a 3/16 or a 3/32 inch die. In those cases where ground pellets were used, the whole pellets were passed through a coffee grinder and ground to a
517
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AS EARLY as 1937, Patten, Buskirk -**- and Rauls reported that chicks fed pelleted rations gained more weight and consumed less feed than chicks fed unpelleted rations. Heywang and Morgan (1944) found that pellet-fed White Leghorn cockerels were significantly heavier at 12 weeks of age than mash-fed birds. An increased feed efficiency with the pelleted ration was also observed. Bearse et al. (1952) observed that the growth response to pelleting was increased as fiber level in the ration was raised from 8 to 18%. Recently, Lanson and Smyth (1955) obtained superior weight and feed conversion when While Plymouth Rock male broilers were fed pellets. An increase in weight and feed efficiency with pelleted rations containing high levels of barley was reported by Lindblad et al. (1955). These workers suggested that the improved performance of broilers on pelleted rations was not due to increased consumption of feed. Contrary to these reports, Stewart and Upp (1951) found that pelleting did not greatly affect the rate of growth or feed efficiency when the ration was fed to broilers in the form of pellets, granules, or mash.
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TABLE 2.—Effect of pelleting rations of different particle size similar to that of mash. energy content on performance of Density of the feed was determined by turkey poults, experiment 1 weighing the amount of feed contained Energy % Feed Av. wt. in a two liter graduate cylinder. of Fat* Form 4 weeks f efficiency % Density basal added Experiment 1. Previous reports had ingms. gms./ml dicated that the response to pelleting was High 0 Mash 566 1.77 .70 High 0 Ground pellet 607 1.61 .65 affected by the energy level of the ration. High 3 Mash 624 1.64 .68 High Ground pellet 642 1.61 .65 3 This experiment was conducted to deter- Low 0 Mash 495 2.01 .63 Low 585 1.80 .64 0 Ground pellet mine the effect of pelleting of high and low Low 3 Mash 560 1.80 .59 3 Ground pellet 585 1.71 .63 energy rations on performance of poults. Low * Stabilized inedible animal tallow. The two basal rations, with and without t High energy vs. low energy, P = < . 0 1 ; 0 % fat vs. 3 % fat, 3 % tallow, were fed in the form of ground NP =.
RESPONSE TO PELLETING or TABLE 3.—Interrelationship of pelleting and fat level of diet on performance of turkey poults, experiment 2
519
FEED
TABLE 4.—Percentage composition of basal diets used in experiment 3 and 4 Experiment
Form
pellets pellets pellets pellets pellets
0 2.5 2.5 2.5 5.0 5.0 5.0
When fat added
Before pelleting After pelleting Before pelleting After pelleting
Ingredient
^wdght
615 573 584 610 574 615 629
* Stabilized inedible animal tallow. t Fat levels, N. S.; Fat added before pelleting vs. fat added after pelleting, N. S.; Ground pellets vs. mash (-j-fat), P = <.01; Ground pellets vs. mash (—fat), P = <.05; Interaction, N. S.
Breasted Bronze poults were used per treatment. Table 1 shows the composition of the basal diet. Animal fat, at levels of 2.5 and 5.0% were added at the expense of the entire ration. The pellets were ground in a coffee grinder to a particle size similar to mash. When fat was added to the rations after pelleting, it was added after the pellets had been ground. The results are presented in Table 3. A significant growth response (P = < .05— without added tallow; P=<.01—with added tallow) was observed in every case when the ration was pelleted. In each case where tallow was added after pelleting, growth was slightly better than when tallow was added before pelleting. However, this difference was not statistically significant. In contrast to Experiment 1, the addition of tallow caused no growth response. Furthermore, the addition of animal tallow to the ration did not decrease the response to pelleting. Experiment 3. This experiment was conducted with chicks to study further the possible interrelationship of fat and pelleting. Five male and five female dayold New Hampshire X White Olympian chicks were placed in each pen and three groups were used per treatment. The composition of the basal diet is given in Table 4. Animal tallow in this experiment was added to the basal diet at the expense of
Ground yellow corn Soybean oil meal (46% protein) Fishmeal herring (73% protein) Dehydrated alfalfa meal (17% protein) Ground limestone Steamed bonemeal Iodized salt Fermentation product* Premixf
3
4
52.7 35 5 3 0.5 2.0 .3 .5 1
58.6 30 5 2.5 0.5 2.0 .3 — .7
* Vigofac, Chas. Pfizer and Co., Inc., Brooklyn, N. Y. t Adds per pound of feed: Vitamin A, 1,2001.U.; vitamin D3, 300 I.C.U.; riboflavin, 2 mg.; calcium pantothenate, 4.2 mg.; niacin, 12 mg.; choline, 600 mg.; penicillin, 2.5 mg.; andMnSO* (feed grade), 100 mg.
corn, being added both before and after pelleting. The results are presented in Table 5. A significant growth response was obtained by pelleting, irrespective of fat level in the diet. No significant growth response was obtained by the addition of animal fat. An improvement in feed utilization was obtained by pelleting at all levels of fat. Improvement in feed utilization was also obtained because of the addition of fat. There was no difference in the response to pelleting, whether the fat was added before or after the pelleting process. Experiment 4. In the previous experiment, pellets were ground to a particle size similar to the original mash. Even though form and density were about the same for mash and ground pellets, a growth response to pelleting was obtained. TABLE 5.—Interrelationship of pelleting and fat on performance of chicks, experiment 3 Fat* level Mash Ground Mash Ground Ground Mash Ground Ground
pellets pellets pellets pellets pellets
'% 0 0 2.5 2.5 2.5 5.0 5.0 5.0
When fat added
• Before pelleting After pelleting Before pelleting After pelleting
Av. wt. Feed 4 weekst emciencyt gms. 367 385 354 387 395 369 383 382
1.93 1.89 1.88 1.76 1.76 1.81 1.79 1.74
* Stabilized inedible animal tallow. t Ground pellets vs. mash, P = <.01; Fat levels, N. S.; Fat added before peUeting lis. fat added after pelleting, N. S.; Interaction, N. S. J Grams feed per gram gain.
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Ground Mash Ground Ground Mash Ground Ground
,**.
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J. B. ALLRED, L. S. JENSEN AND J. MCGINNIS
TABLE 6.—Effect of form of feed on the performance of chicks, experiment 4 Form
Mash Ground pellets Pellets
Av. wt. Feed 4 weeks* efficiency! gms. 377 396 397
1.86 1.82 1.91
Densitv
'
gms./ml. .67 .66 .64
This experiment was undertaken to compare the effect of feeding whole pellets, ground pellets, and unpelleted mash to chicks. Four groups of five male and five female New Hampshire X White Olympian day-old chicks were used per treatment. Composition of the diet used in this study is presented in Table 4. The ration was pelleted, using a 3/32 inch die. Table 6 shows the result of this experiment. A significant growth response (P = < .05) was obtained with both ground pellets and whole pellets. No signifTABLE 7.—Percentage composition of basal diets used in Experiment 5
1
2
%
protein
Diet No. T
TABLE 8.—Relationship between physical form and protein level of the diet and chick performance, Experiment 5
Form of diet
3
A-
% protein 20 Corn 50 8 Cellulose Animal tallow* 3 Protein mixf 30 2.5 Dehydrated alfalfa meal (17% protein) Distillers dried solubles 3 2.5 Steamed bone meal .5 Ground limestone Salt .3 .5 Premixf
22 SO 4 3 34 2.5 3 2.5 .5 .3 .5
24 50 3 38 2.5 3 2.5 .5 .3 .5
* Stabilized inedible animal tallow. t Protein mix: 23 parts soybean oil meal to 5 parts fish meal, herring. t Adds per pound of feed: Vitamin A, 1,000 I.U.; vitamin D 3 , 150 I.C.U.; riboflavin, 1.3 mg.; penicillin, 1.5 mg.; MnSOa (feed grade), 100 mg.
20 20 20 20 22 22 22 22 24 24 24 24
Mash Ground pellets Pellets Mash Crumbles Ground pellets Pellets Mash Crumbles Ground pellets Pellets
Av. wt. 4 weeks*
gms. 339 377 365 384 354 367 354 365 350 371 378 385
Feed efficiency,! gms. feed/gm. gain 2.22 1 98 1.92 2 03 2.16 1.84 1.93 2.14 2.03 1.94 1.86 1.92
* Analysis of Variance: Pelleting vs. not pelleting, P = <.01, protein level,, N. S.; Interaction, lets, P = <.05; Mash vs. crumbles, P = < . 0 1 ; Mash vs. pellets, P = < . 0 1 ; ground pellets vs. crumbles vs. pellets, N. S. f Analysis of variance: Pelleting vs. not pelleting, P = < . 0 1 ; protein level, P = < . 0 5 ; Interaction, N. S.
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* Pelleting vs. not pelleting, P < . 0 5 . f Grams feed per gram gain. Pelleting vs. not pelleting, N. S.
icant difference in feed utilization was observed in this experiment. Experiment 5. This experiment was conducted to study the effect of protein level of the diet on the response to pelleting. The effect of feeding the same feeds in the four different forms shown in Table 8 was also studied. Three pens of five male and five female White Rock X White Olympian day-old chicks were used per treatment. Composition of the basal diets is given in Table 7. These diets provided calculated protein levels of approximately 20, 22, and 24%. These protein levels were used with corresponding levels of productive energy (calculated from values of Fraps, 1946) of 881, 905, and 931 Cal./lb., respectively. The only ingredients changed in these diets as protein level was increased were the protein mixture and cellulose. Pellets were made by using a 3/32 inch die. Ground pellets and crum-
RESPONSE TO PELLETING OF FEED
DISCUSSION
Results of the first three experiments showed that the growth response obtained by pelleting feeds is still retained even though animal fat is added to the ration. In the first experiment, the growth effect appeared to be reduced by the addition of fat. In the other two experiments, however, the pelleting process response was about the same when 0, 2.5, or 5% animal
tallow was added to the diet. The idea that fat added before pelleting would cause the feed to go through the die so fast that the full effect of pelleting pressure would not be realized was not proven. In Experiment 5, the growth response and feed efficiency effect obtained by pelleting was unchanged by varying the protein level from 20 to 24%. In the first three experiments, it was necessary to grind the pellets because the pellets obtained were too large for day-old chicks and poults to eat. It was interesting that a growth response to pelleting was still obtained even though the pellets were ground to a consistency similar to the original mash. It has been suggested by several workers that the growth response to pelleting is due largely to the physical form. These results using ground pellets suggest that physical form does not completely explain the pelleting effect. In Experiment 4, it was found that the same magnitude of growth response was obtained whether the pelleted feeds were fed in the form of ground pellets or as whole pellets. In Experiment 5, the growth response and feed efficiency effect obtained by pelleting was observed when the pellets were fed in the form of ground pellets, simulated crumbles or whole pellets. The fastest growth rate in the experiment wasobtained by feeding whole pellets. The whole pellets in Experiments 4 and 5 were 3/32 inch in diameter and are supposedly suitable for young chicks and poults. It was observed, however, that the chicks appeared to have some difficulty consuming the pellets during the first week or two. This difficulty was especially noticeable in Experiment 4, where no animal fat was in the ration. In this case the pellets were quite hard and did not readily fall apart when pecked by the chicks. The feed in Experiment 5 contained 3 % animal tallow which provided
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bles were made by grinding in a coffee grinder at two different adjustments. The resulting crumbles were slightly smaller than commercial crumbles. Results of this experiment are presented in Table 8. A highly significant growth response (analysis of variance) was obtained from pelleting. There was no significant difference, however, in the growth obtained from the three different protein levels of the rations. Furthermore, there was no significant interaction between pelleting and protein levels. Comparisons of the growth obtained when the rations were fed in the four different forms were made with Duncan's Multiple F Test. The results of this analysis were as follows: mash versus ground pellets—approaching significance at the 1% level; mash versus crumbles— significant at the 1% level; mash versus pellets—significant at the 1% level; and ground pellets versus crumbles versus pellets—no significant difference. A highly significant improvement of feed utilization ( P = < . 0 1 ) and feed efficiency was observed due to pelleting. A significant improvement in feed utilization was also observed (P = < .05) with increasing protein levels. This increase in feed efficiency was undoubtedly accounted for by the increase in energy level in the diets. There was no significant effect on feed efficiency caused by interaction between protein level and pelleting.
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J. B. ALLRED, L. S. JENSEN AND J. MCGINNIS
linseed meal (Heuser et al., 1946; and others). Although the chemical change brought about by the pelleting process may explain a part of the growth response obtained by pelleting, it is still probable that the physical form contributes something to the increased growth when the feed is fed as whole pellets. It has been observed that birds fed feed in pellet form can consume their feed more rapidly than birds fed feed in mash form. Some of the growth increase, therefore, may be brought about by an increase in feed consumption when pellets are fed. SUMMARY
1. Five experiments were conducted to study the effect of pelleting rations on growth and feed efficiency of chicks and poults, and to study the relationships of pelleting to the protein and fat content of the ration. 2. Pelleting the rations improved growth rate and feed efficiency of both species. 3. A growth response to pelleting was obtained, even when the pellets were ground to a particle size and density similar to the original mash. 4. The pelleting effect of increased growth and efficiency was obtained whether or not animal fat was added to the ration. 5. Rations containing protein levels varying from 20 to 24% gave the same response to pelleting. 6. It is concluded that a large part of the increased growth and feed efficiency effect obtained by pelleting may be due to some chemical change, possibly the inactivation of a growth inhibitor in the ration. ACKNOWLEDGMENTS
The authors wish to express their appreciation to the California Pellet Mill
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softer pellets and more fines. The ability of the chicks to eat the softer pellets more readily may explain why feeding whole pellets gave greater response than crumbles and ground pellets in Experiment 5. It has been observed in other experiments at this Experiment Station that whole pellets containing some fat usually give a greater growth response than the same pellets in ground form. The results of this series of experiments clearly demonstrate that a growth response is obtained by pelleting feeds, even though the pellets are ground to a particle size and density similar to the original mash. This finding suggests that some chemical change which occurs when the ration is pelleted accounts for the growth stimulation. The nature of this chemical change is of interest. It is possible that the high pressure and the steam used in the pelleting process alter the ingredients so that more energy or protein is made available to the animal. This explanation, however, is not very plausible when one considers that in the experiments reported in this paper, a growth response was obtained even though the energy and protein levels of the ration were increased. Perhaps a more logical explanation for the chemical effect brought about by pelleting would be the destruction of some toxic substance or inhibitor naturally present in feed ingredients. Considerable evidence has accumulated that certain feed ingredients used in poultry feeds contain various types of growth inhibitors. Evidence for an inhibitor in alfalfa has been reported by Cooney et al. (1948), and others. There has also been evidence for growth inhibitors in vegetable protein concentrates such as the trypsin inhibitor in raw soybean meal (Ham et al., 1945; and others), gossypol in cottonseed meal (reviewed by Milligan and Bird, 1951), and a toxic substance in
RESPONSE TO PELLETING OF FEED
Company, San Francisco, California for the pellet mill used in these studies; to Merck and Company, Inc., Rah way, New Jersey, and Dawe's Laboratories, Inc., Auburn, Washington for vitamins used in these experiments; and to Dr. T. S. Russell for valuable assistance in the statistical analysis of the data.
1945. The proteolytic inhibiting substance in the extract from unheated soybean meal and it's effect upon growth of chicks. J. Biol. Chem. 161: 635-642. Heuser, G. F., L. C. Norris and J. McGinnis, 1946. Vegetable protein concentrates fed alone and in combination with soybean oil meal and fish meal as the chief supplementary protein in chick starting rations. Poultry Sci. 25: 130-136. Heywang, B. W., and R. B. Morgan, 1944. Pelleted and unpelleted all-mash diet for growing chickens. Poultry Sci. 23: 16-20. Lanson, R. K., and J. R. Smyth, 1955. Pellets versus mash plus pellets versus mash for broilers. Poultry Sci. 34: 234-236. Lindblad, G. S., J. R. Aitken and W. G. Hansaker, 1955. Studies on the use of barley in broiler rations. Poultry Sci. 34: 1208. Milligan, J. L., and H. R. Bird, 1951. Effect of processing variants on the nutritive value of cottonseed meal for chicks. Poultry Sci. 30: 651-657. Patten, J. W., H. H. Buskirk and L. A. Rauls, 1937. A study of the relative merits of pellets and mash poultry feeds. Vet. Med. 32: 423^27. Stewart, W. I., and C. W. Upp, 1951. Effect of form feed on growth and feed efficiency, pellets versus mash versus granules for broilers. Poultry Sci. 30: 63-66. Waibel, P. E., 1955. Effect of dietary protein level and added tallow on growth and carcass composition of chicks. Poultry Sci. 34: 1226. Ziegenhagen, E. H., L. B. Corman and J. W. Hayward, 1947. Feed particle size as a factor affecting performance of turkey poults. Poultry Sci. 26: 212-214.
NEWS AND NOTES {Continued from page 516) honorary life member of the Federation, for outstanding contributions to the welfare of the turkey industry. BACK ISSUES Issues Wanted.—Dr. J. M. Gwin, RalstonPurina Company, Checkerboard Square, St. Louis 2, Missouri—Volume 2, No. 4; Volume 3, No. 2; Volume 11, No. 1, and Volume 18, No. 1. A.F.B.F. NOTES H. H. Alp has been appointed to a new staff position of Director of Market Development of the American Farm Bureau Federation. He joined the A.F.B .F. staff in 1947 as Poultry Director in the Commodity Department.
NATIONAL BROILER COUNCIL At the Annual Board of Directors meeting of the National Broiler Council held in Ponte Vedra, Florida, the following officers were elected: President—J. Fechtel, Western Hatcheries, Dallas, Texas; Vice-President for the Northeast—H. Saglio, Arbor Acres Farm, Glastonbury, Connecticut; VicePresident for the Southeast—R. Firestone, Firestone and Company, Inc., Troutville, Virginia; Vice-President for the Midwest—G. R. Peterson, Pillsburg Mills, Clinton, Iowa; Vice-President for the West—J. Linn, Linn's Hatchery, Puyallup, Washington; Vice-President—at Large—H. H. Earthman, Murfreesboro, Tennessee; Treasurer— R. Cleveland, Gainesville Milling Company, Gaines-
(Continued on page 538)
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REFERENCES Aitken, J. R., G. S. Lindblad and W. G. Hunsaker, 1954. Beef tallow as a source of energy in broiler rations. Poultry Sci. 33: 1038. Bearse, G. E., L. R. Berg, C. F. McClary and V. L. Miller, 1952. Effect on chick growth of pelleting rations with different fiber levels. Poultry Sci. 31:907. Biely, J., and B. March, 1954. Fat studies in poultry, 2. Fat supplements in chick and poult rations. Poultry Sci. 33:1220-1227. Cooney, W. T., J. S. Butts and L. E. Bacon, 1948. Alfalfa meal in chick rations. Poultry Sci. 27: 828-830. Duncan, D. B., 1955. Multiple range and multiple F test. Biometrics, 11 (1): 1-42. Dymsza, H., R. V. Boucher and M. G. McCartney, 1955. The influence of fiber content and physical form of the diet on the energy requirements of turkeys. 1. Studies with turkey poults. Poultry Sci. 34: 435-439. Fraps, G. S., 1946. Composition and productive energy of poultry feeds and rations. Texas Agr. Exp. Sta. Bui. 678. Ham, W. E., R. M. Standstedt and F. E. Mussehl,
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Department of Poultry Science, State College of Washington, Pullman, Washington (Received for publication November 13, 1956)
Research with turkey poults has demonstrated that increased growth and feed efficiency result when rations are pelleted. Ziegenhagen et al. (1947) reported a significant increase in growth of turkey poults when mash rations were fed in the form of pellets or granules. 1 Scientific Paper No. 1545, Washington Agricultural Experiment Stations, Project 1304.
Efficiency of feed utilization was also improved. Dymsza et al. (1955), using rations containing 5, 10, and 15% fiber, showed that pelleting and subsequent crumbling concentrated the nutrients and counteracted some of the adverse effects of low energy diets when fed to poults. Many reports on the use of animal tallow in poultry rations have appeared recently (Aitken et al., 1954; Biely and March, 1954; Waibel 1955; and others). Most of the reports showed that feed efficiency increased when animal tallow was added to the ration. In some cases, increased growth rate was also observed. The experiments reported herein were undertaken to study further the effect of pelleting feeds upon the performance of chicks and poults and to determine the effect of animal tallow and protein level in relation to the response obtained by pelleting. PROCEDURE AND RESULTS
In the following series of experiments all of the turkey poults and chicks were housed in electrically-heated, wire-floored battery brooders. The birds received food and water ad libitum during the experimental period. Group body weights and feed consumption data were obtained at weekly intervals. The experiments were terminated at the end of 4 weeks. The pelleted feeds used in these experiments were made with a California pellet mill, using either a 3/16 or a 3/32 inch die. In those cases where ground pellets were used, the whole pellets were passed through a coffee grinder and ground to a
517
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AS EARLY as 1937, Patten, Buskirk -**- and Rauls reported that chicks fed pelleted rations gained more weight and consumed less feed than chicks fed unpelleted rations. Heywang and Morgan (1944) found that pellet-fed White Leghorn cockerels were significantly heavier at 12 weeks of age than mash-fed birds. An increased feed efficiency with the pelleted ration was also observed. Bearse et al. (1952) observed that the growth response to pelleting was increased as fiber level in the ration was raised from 8 to 18%. Recently, Lanson and Smyth (1955) obtained superior weight and feed conversion when While Plymouth Rock male broilers were fed pellets. An increase in weight and feed efficiency with pelleted rations containing high levels of barley was reported by Lindblad et al. (1955). These workers suggested that the improved performance of broilers on pelleted rations was not due to increased consumption of feed. Contrary to these reports, Stewart and Upp (1951) found that pelleting did not greatly affect the rate of growth or feed efficiency when the ration was fed to broilers in the form of pellets, granules, or mash.
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J. B. ALLRED, L. S. JENSEN AND J. MCGINNIS
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TABLE 2.—Effect of pelleting rations of different particle size similar to that of mash. energy content on performance of Density of the feed was determined by turkey poults, experiment 1 weighing the amount of feed contained Energy % Feed Av. wt. in a two liter graduate cylinder. of Fat* Form 4 weeks f efficiency % Density basal added Experiment 1. Previous reports had ingms. gms./ml dicated that the response to pelleting was High 0 Mash 566 1.77 .70 High 0 Ground pellet 607 1.61 .65 affected by the energy level of the ration. High 3 Mash 624 1.64 .68 High Ground pellet 642 1.61 .65 3 This experiment was conducted to deter- Low 0 Mash 495 2.01 .63 Low 585 1.80 .64 0 Ground pellet mine the effect of pelleting of high and low Low 3 Mash 560 1.80 .59 3 Ground pellet 585 1.71 .63 energy rations on performance of poults. Low * Stabilized inedible animal tallow. The two basal rations, with and without t High energy vs. low energy, P = < . 0 1 ; 0 % fat vs. 3 % fat, 3 % tallow, were fed in the form of ground NP =.
RESPONSE TO PELLETING or TABLE 3.—Interrelationship of pelleting and fat level of diet on performance of turkey poults, experiment 2
519
FEED
TABLE 4.—Percentage composition of basal diets used in experiment 3 and 4 Experiment
Form
pellets pellets pellets pellets pellets
0 2.5 2.5 2.5 5.0 5.0 5.0
When fat added
Before pelleting After pelleting Before pelleting After pelleting
Ingredient
^wdght
615 573 584 610 574 615 629
* Stabilized inedible animal tallow. t Fat levels, N. S.; Fat added before pelleting vs. fat added after pelleting, N. S.; Ground pellets vs. mash (-j-fat), P = <.01; Ground pellets vs. mash (—fat), P = <.05; Interaction, N. S.
Breasted Bronze poults were used per treatment. Table 1 shows the composition of the basal diet. Animal fat, at levels of 2.5 and 5.0% were added at the expense of the entire ration. The pellets were ground in a coffee grinder to a particle size similar to mash. When fat was added to the rations after pelleting, it was added after the pellets had been ground. The results are presented in Table 3. A significant growth response (P = < .05— without added tallow; P=<.01—with added tallow) was observed in every case when the ration was pelleted. In each case where tallow was added after pelleting, growth was slightly better than when tallow was added before pelleting. However, this difference was not statistically significant. In contrast to Experiment 1, the addition of tallow caused no growth response. Furthermore, the addition of animal tallow to the ration did not decrease the response to pelleting. Experiment 3. This experiment was conducted with chicks to study further the possible interrelationship of fat and pelleting. Five male and five female dayold New Hampshire X White Olympian chicks were placed in each pen and three groups were used per treatment. The composition of the basal diet is given in Table 4. Animal tallow in this experiment was added to the basal diet at the expense of
Ground yellow corn Soybean oil meal (46% protein) Fishmeal herring (73% protein) Dehydrated alfalfa meal (17% protein) Ground limestone Steamed bonemeal Iodized salt Fermentation product* Premixf
3
4
52.7 35 5 3 0.5 2.0 .3 .5 1
58.6 30 5 2.5 0.5 2.0 .3 — .7
* Vigofac, Chas. Pfizer and Co., Inc., Brooklyn, N. Y. t Adds per pound of feed: Vitamin A, 1,2001.U.; vitamin D3, 300 I.C.U.; riboflavin, 2 mg.; calcium pantothenate, 4.2 mg.; niacin, 12 mg.; choline, 600 mg.; penicillin, 2.5 mg.; andMnSO* (feed grade), 100 mg.
corn, being added both before and after pelleting. The results are presented in Table 5. A significant growth response was obtained by pelleting, irrespective of fat level in the diet. No significant growth response was obtained by the addition of animal fat. An improvement in feed utilization was obtained by pelleting at all levels of fat. Improvement in feed utilization was also obtained because of the addition of fat. There was no difference in the response to pelleting, whether the fat was added before or after the pelleting process. Experiment 4. In the previous experiment, pellets were ground to a particle size similar to the original mash. Even though form and density were about the same for mash and ground pellets, a growth response to pelleting was obtained. TABLE 5.—Interrelationship of pelleting and fat on performance of chicks, experiment 3 Fat* level Mash Ground Mash Ground Ground Mash Ground Ground
pellets pellets pellets pellets pellets
'% 0 0 2.5 2.5 2.5 5.0 5.0 5.0
When fat added
• Before pelleting After pelleting Before pelleting After pelleting
Av. wt. Feed 4 weekst emciencyt gms. 367 385 354 387 395 369 383 382
1.93 1.89 1.88 1.76 1.76 1.81 1.79 1.74
* Stabilized inedible animal tallow. t Ground pellets vs. mash, P = <.01; Fat levels, N. S.; Fat added before peUeting lis. fat added after pelleting, N. S.; Interaction, N. S. J Grams feed per gram gain.
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Ground Mash Ground Ground Mash Ground Ground
,**.
520
J. B. ALLRED, L. S. JENSEN AND J. MCGINNIS
TABLE 6.—Effect of form of feed on the performance of chicks, experiment 4 Form
Mash Ground pellets Pellets
Av. wt. Feed 4 weeks* efficiency! gms. 377 396 397
1.86 1.82 1.91
Densitv
'
gms./ml. .67 .66 .64
This experiment was undertaken to compare the effect of feeding whole pellets, ground pellets, and unpelleted mash to chicks. Four groups of five male and five female New Hampshire X White Olympian day-old chicks were used per treatment. Composition of the diet used in this study is presented in Table 4. The ration was pelleted, using a 3/32 inch die. Table 6 shows the result of this experiment. A significant growth response (P = < .05) was obtained with both ground pellets and whole pellets. No signifTABLE 7.—Percentage composition of basal diets used in Experiment 5
1
2
%
protein
Diet No. T
TABLE 8.—Relationship between physical form and protein level of the diet and chick performance, Experiment 5
Form of diet
3
A-
% protein 20 Corn 50 8 Cellulose Animal tallow* 3 Protein mixf 30 2.5 Dehydrated alfalfa meal (17% protein) Distillers dried solubles 3 2.5 Steamed bone meal .5 Ground limestone Salt .3 .5 Premixf
22 SO 4 3 34 2.5 3 2.5 .5 .3 .5
24 50 3 38 2.5 3 2.5 .5 .3 .5
* Stabilized inedible animal tallow. t Protein mix: 23 parts soybean oil meal to 5 parts fish meal, herring. t Adds per pound of feed: Vitamin A, 1,000 I.U.; vitamin D 3 , 150 I.C.U.; riboflavin, 1.3 mg.; penicillin, 1.5 mg.; MnSOa (feed grade), 100 mg.
20 20 20 20 22 22 22 22 24 24 24 24
Mash Ground pellets Pellets Mash Crumbles Ground pellets Pellets Mash Crumbles Ground pellets Pellets
Av. wt. 4 weeks*
gms. 339 377 365 384 354 367 354 365 350 371 378 385
Feed efficiency,! gms. feed/gm. gain 2.22 1 98 1.92 2 03 2.16 1.84 1.93 2.14 2.03 1.94 1.86 1.92
* Analysis of Variance: Pelleting vs. not pelleting, P = <.01, protein level,, N. S.; Interaction, lets, P = <.05; Mash vs. crumbles, P = < . 0 1 ; Mash vs. pellets, P = < . 0 1 ; ground pellets vs. crumbles vs. pellets, N. S. f Analysis of variance: Pelleting vs. not pelleting, P = < . 0 1 ; protein level, P = < . 0 5 ; Interaction, N. S.
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* Pelleting vs. not pelleting, P < . 0 5 . f Grams feed per gram gain. Pelleting vs. not pelleting, N. S.
icant difference in feed utilization was observed in this experiment. Experiment 5. This experiment was conducted to study the effect of protein level of the diet on the response to pelleting. The effect of feeding the same feeds in the four different forms shown in Table 8 was also studied. Three pens of five male and five female White Rock X White Olympian day-old chicks were used per treatment. Composition of the basal diets is given in Table 7. These diets provided calculated protein levels of approximately 20, 22, and 24%. These protein levels were used with corresponding levels of productive energy (calculated from values of Fraps, 1946) of 881, 905, and 931 Cal./lb., respectively. The only ingredients changed in these diets as protein level was increased were the protein mixture and cellulose. Pellets were made by using a 3/32 inch die. Ground pellets and crum-
RESPONSE TO PELLETING OF FEED
DISCUSSION
Results of the first three experiments showed that the growth response obtained by pelleting feeds is still retained even though animal fat is added to the ration. In the first experiment, the growth effect appeared to be reduced by the addition of fat. In the other two experiments, however, the pelleting process response was about the same when 0, 2.5, or 5% animal
tallow was added to the diet. The idea that fat added before pelleting would cause the feed to go through the die so fast that the full effect of pelleting pressure would not be realized was not proven. In Experiment 5, the growth response and feed efficiency effect obtained by pelleting was unchanged by varying the protein level from 20 to 24%. In the first three experiments, it was necessary to grind the pellets because the pellets obtained were too large for day-old chicks and poults to eat. It was interesting that a growth response to pelleting was still obtained even though the pellets were ground to a consistency similar to the original mash. It has been suggested by several workers that the growth response to pelleting is due largely to the physical form. These results using ground pellets suggest that physical form does not completely explain the pelleting effect. In Experiment 4, it was found that the same magnitude of growth response was obtained whether the pelleted feeds were fed in the form of ground pellets or as whole pellets. In Experiment 5, the growth response and feed efficiency effect obtained by pelleting was observed when the pellets were fed in the form of ground pellets, simulated crumbles or whole pellets. The fastest growth rate in the experiment wasobtained by feeding whole pellets. The whole pellets in Experiments 4 and 5 were 3/32 inch in diameter and are supposedly suitable for young chicks and poults. It was observed, however, that the chicks appeared to have some difficulty consuming the pellets during the first week or two. This difficulty was especially noticeable in Experiment 4, where no animal fat was in the ration. In this case the pellets were quite hard and did not readily fall apart when pecked by the chicks. The feed in Experiment 5 contained 3 % animal tallow which provided
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bles were made by grinding in a coffee grinder at two different adjustments. The resulting crumbles were slightly smaller than commercial crumbles. Results of this experiment are presented in Table 8. A highly significant growth response (analysis of variance) was obtained from pelleting. There was no significant difference, however, in the growth obtained from the three different protein levels of the rations. Furthermore, there was no significant interaction between pelleting and protein levels. Comparisons of the growth obtained when the rations were fed in the four different forms were made with Duncan's Multiple F Test. The results of this analysis were as follows: mash versus ground pellets—approaching significance at the 1% level; mash versus crumbles— significant at the 1% level; mash versus pellets—significant at the 1% level; and ground pellets versus crumbles versus pellets—no significant difference. A highly significant improvement of feed utilization ( P = < . 0 1 ) and feed efficiency was observed due to pelleting. A significant improvement in feed utilization was also observed (P = < .05) with increasing protein levels. This increase in feed efficiency was undoubtedly accounted for by the increase in energy level in the diets. There was no significant effect on feed efficiency caused by interaction between protein level and pelleting.
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J. B. ALLRED, L. S. JENSEN AND J. MCGINNIS
linseed meal (Heuser et al., 1946; and others). Although the chemical change brought about by the pelleting process may explain a part of the growth response obtained by pelleting, it is still probable that the physical form contributes something to the increased growth when the feed is fed as whole pellets. It has been observed that birds fed feed in pellet form can consume their feed more rapidly than birds fed feed in mash form. Some of the growth increase, therefore, may be brought about by an increase in feed consumption when pellets are fed. SUMMARY
1. Five experiments were conducted to study the effect of pelleting rations on growth and feed efficiency of chicks and poults, and to study the relationships of pelleting to the protein and fat content of the ration. 2. Pelleting the rations improved growth rate and feed efficiency of both species. 3. A growth response to pelleting was obtained, even when the pellets were ground to a particle size and density similar to the original mash. 4. The pelleting effect of increased growth and efficiency was obtained whether or not animal fat was added to the ration. 5. Rations containing protein levels varying from 20 to 24% gave the same response to pelleting. 6. It is concluded that a large part of the increased growth and feed efficiency effect obtained by pelleting may be due to some chemical change, possibly the inactivation of a growth inhibitor in the ration. ACKNOWLEDGMENTS
The authors wish to express their appreciation to the California Pellet Mill
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softer pellets and more fines. The ability of the chicks to eat the softer pellets more readily may explain why feeding whole pellets gave greater response than crumbles and ground pellets in Experiment 5. It has been observed in other experiments at this Experiment Station that whole pellets containing some fat usually give a greater growth response than the same pellets in ground form. The results of this series of experiments clearly demonstrate that a growth response is obtained by pelleting feeds, even though the pellets are ground to a particle size and density similar to the original mash. This finding suggests that some chemical change which occurs when the ration is pelleted accounts for the growth stimulation. The nature of this chemical change is of interest. It is possible that the high pressure and the steam used in the pelleting process alter the ingredients so that more energy or protein is made available to the animal. This explanation, however, is not very plausible when one considers that in the experiments reported in this paper, a growth response was obtained even though the energy and protein levels of the ration were increased. Perhaps a more logical explanation for the chemical effect brought about by pelleting would be the destruction of some toxic substance or inhibitor naturally present in feed ingredients. Considerable evidence has accumulated that certain feed ingredients used in poultry feeds contain various types of growth inhibitors. Evidence for an inhibitor in alfalfa has been reported by Cooney et al. (1948), and others. There has also been evidence for growth inhibitors in vegetable protein concentrates such as the trypsin inhibitor in raw soybean meal (Ham et al., 1945; and others), gossypol in cottonseed meal (reviewed by Milligan and Bird, 1951), and a toxic substance in
RESPONSE TO PELLETING OF FEED
Company, San Francisco, California for the pellet mill used in these studies; to Merck and Company, Inc., Rah way, New Jersey, and Dawe's Laboratories, Inc., Auburn, Washington for vitamins used in these experiments; and to Dr. T. S. Russell for valuable assistance in the statistical analysis of the data.
1945. The proteolytic inhibiting substance in the extract from unheated soybean meal and it's effect upon growth of chicks. J. Biol. Chem. 161: 635-642. Heuser, G. F., L. C. Norris and J. McGinnis, 1946. Vegetable protein concentrates fed alone and in combination with soybean oil meal and fish meal as the chief supplementary protein in chick starting rations. Poultry Sci. 25: 130-136. Heywang, B. W., and R. B. Morgan, 1944. Pelleted and unpelleted all-mash diet for growing chickens. Poultry Sci. 23: 16-20. Lanson, R. K., and J. R. Smyth, 1955. Pellets versus mash plus pellets versus mash for broilers. Poultry Sci. 34: 234-236. Lindblad, G. S., J. R. Aitken and W. G. Hansaker, 1955. Studies on the use of barley in broiler rations. Poultry Sci. 34: 1208. Milligan, J. L., and H. R. Bird, 1951. Effect of processing variants on the nutritive value of cottonseed meal for chicks. Poultry Sci. 30: 651-657. Patten, J. W., H. H. Buskirk and L. A. Rauls, 1937. A study of the relative merits of pellets and mash poultry feeds. Vet. Med. 32: 423^27. Stewart, W. I., and C. W. Upp, 1951. Effect of form feed on growth and feed efficiency, pellets versus mash versus granules for broilers. Poultry Sci. 30: 63-66. Waibel, P. E., 1955. Effect of dietary protein level and added tallow on growth and carcass composition of chicks. Poultry Sci. 34: 1226. Ziegenhagen, E. H., L. B. Corman and J. W. Hayward, 1947. Feed particle size as a factor affecting performance of turkey poults. Poultry Sci. 26: 212-214.
NEWS AND NOTES {Continued from page 516) honorary life member of the Federation, for outstanding contributions to the welfare of the turkey industry. BACK ISSUES Issues Wanted.—Dr. J. M. Gwin, RalstonPurina Company, Checkerboard Square, St. Louis 2, Missouri—Volume 2, No. 4; Volume 3, No. 2; Volume 11, No. 1, and Volume 18, No. 1. A.F.B.F. NOTES H. H. Alp has been appointed to a new staff position of Director of Market Development of the American Farm Bureau Federation. He joined the A.F.B .F. staff in 1947 as Poultry Director in the Commodity Department.
NATIONAL BROILER COUNCIL At the Annual Board of Directors meeting of the National Broiler Council held in Ponte Vedra, Florida, the following officers were elected: President—J. Fechtel, Western Hatcheries, Dallas, Texas; Vice-President for the Northeast—H. Saglio, Arbor Acres Farm, Glastonbury, Connecticut; VicePresident for the Southeast—R. Firestone, Firestone and Company, Inc., Troutville, Virginia; Vice-President for the Midwest—G. R. Peterson, Pillsburg Mills, Clinton, Iowa; Vice-President for the West—J. Linn, Linn's Hatchery, Puyallup, Washington; Vice-President—at Large—H. H. Earthman, Murfreesboro, Tennessee; Treasurer— R. Cleveland, Gainesville Milling Company, Gaines-
(Continued on page 538)
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REFERENCES Aitken, J. R., G. S. Lindblad and W. G. Hunsaker, 1954. Beef tallow as a source of energy in broiler rations. Poultry Sci. 33: 1038. Bearse, G. E., L. R. Berg, C. F. McClary and V. L. Miller, 1952. Effect on chick growth of pelleting rations with different fiber levels. Poultry Sci. 31:907. Biely, J., and B. March, 1954. Fat studies in poultry, 2. Fat supplements in chick and poult rations. Poultry Sci. 33:1220-1227. Cooney, W. T., J. S. Butts and L. E. Bacon, 1948. Alfalfa meal in chick rations. Poultry Sci. 27: 828-830. Duncan, D. B., 1955. Multiple range and multiple F test. Biometrics, 11 (1): 1-42. Dymsza, H., R. V. Boucher and M. G. McCartney, 1955. The influence of fiber content and physical form of the diet on the energy requirements of turkeys. 1. Studies with turkey poults. Poultry Sci. 34: 435-439. Fraps, G. S., 1946. Composition and productive energy of poultry feeds and rations. Texas Agr. Exp. Sta. Bui. 678. Ham, W. E., R. M. Standstedt and F. E. Mussehl,
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