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Interactions of Fats and Fatty Acids as Energy Sources for the Chick
994
G. MADIEDO, E.
F. RICHTER AND M.
L.
SUNDE
REFERENCES
Several procedures for analyzing feedstuffs for xanthophyll were used. All the feedstuffs analyzed were fed to laying hens, and the values obtained by chemical assay were compared with the biological results. The following extraction procedures were found to give values which agree fairly well with the biological results:
Bickoff, E. M., A. L. Livingston, G. F. Bailey and C. R. Thompson, 1954. Xanthophyll determination in dehydrated alfalfa meal. J. Assoc. Off. Agric. Chem. 37: 894-902. Brambila, S., J. A. Pino and C. Mendoza, 1962. Studies with a natural source of xanthophylls for the pigmentation of egg yolks and skin of poultry. Poultry Sci. 41: 1629. Heiman, V., and J. S. Carver, 1935. The yolk color index. U. S. Egg Poultry Magazine, 41(8): 40-41. Jenson, A., 1963. The effect of several carotenoids on egg yolk coloration. Poultry Sci. 42: 912-916. Madiedo, G., and M. L. Sunde, 1964. The effect of algae, dried lake weed, alfalfa and ethoxyquin on yolk color. Poultry Sci. 43: 1056-1061. Morehouse, A. L., 1962. Personal communication. Morehouse, A. L., and A. W. Hanson, 1961. Pigmentation studies with dried algae meal. Informal Poultry Nutr. Conf., Atlantic City, N. J. Quackenbush, F. W., J. G. Firch, W. J. Rabourn, M. McQuistan, E. N. Petzold and T. E. Kargl, 1961. Analysis of carotenoids in corn grain. J. Agr. Food Chem. 9: 132-35.
Corn:
Saponification with alcoholic potassium hydroxide and extraction with petroleum ether.
Algae:
Saponification with alcoholic potassium hydroxide and extraction with ethyl ether.
Marigold petals: Direct extract on with chloroform. Alfalfa meal: Overnight extraction with an acetone-hexane mixture.
Interactions of Fats and Fatty Acids as Energy Sources for the Chick N E I L R.
ARTMAN
The Procter &* Gamble Company, Miami Valley Laboratories, Cincinnati 39, Ohio (Received for publication February 7, 1964)
ATS and fatty acids, like other feedstuff ingredients used as energy sources for the growing chick, have been assigned metabolizable energy (M.E.) values which are widely used in the formulation of rations. Experimental findings by Sibbald et al. (1960, 1961) seemed to raise doubts, however, about the applicability of published M.E. values for individual fatty substances in mixtures of different kinds of fats. They found that a 50/50 mixture by weight of soybean oil, having an M.E. value of 8.46 Cal./g., and tallow, M.E. 6.94 Cal./g., had an M.E. value of 8.41 Cal./g. Simple arithmetic indicated that
F
the M.E. of the tallow in the mixture must have ben raised to 8.36 Cal./g., and it was postulated that the non-degummed soybean oil might have contained a factor, such as phospholipids, which increased the digestibility of the tallow. Although other reports (Pepper et al., 1962; Dangoumau and Debruyne, 1963) have failed to show any advantages gained by mixing different kinds of fat, a recent publication by Sibbald et al. (1962) suggested that some samples of so-called tallow are more susceptible than others to having their M.E. values raised by admixture with soybean oil. Although these work-
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SUMMARY
995
INTERACTIONS OF FATS AND FATTY ACIDS
TABLE 1.—Fats used in feeding studies Fat Soybean oil (Refined & bleached) Soybean oil fatty acids Prime beef tallow Tallow fatty acids Acidulated soapstock from soybean oil refining Menhaden fish oil
Saponification value
Acid value
Iodine value
193 198 196 204
0.1 195 0.7 203
130 135 43.8 45.5
187 193
75 1.4
128 151
utilization resulting from admixture of them with fish oil. In the work to be reported here, four experiments were carried out in order (a) to verify the original observations of Sibbald et al., (b) to extend them, if possible, to other types of fatty material, especially free fatty acids, and (c) to determine whether fish oil, like soybean oil, is able to increase the utilizability of tallow. Comparisons of fat utilizability by conventional techniques are expensive and time-comsuming. A simpler method, based on controlled feed intake, has been described (Young and Artman, 1961), but its validity has been tested in relatively few published experiments. Hence, a further, although incidental, purpose of this work was to compare the evaluation of fatty materials by the controlled feeding method with evaluation by measurements of growth, feed efficiency, digestibility, and metabolizable energy. EXPERIMENTAL MATERIALS AND TECHNIQUES
The fats and fatty acids fed in the various experiments were characterized by the analytical values shown in Table 1. The soybean oil fatty acids and tallow fatty acids were prepared by alkaline hydrolysis of the respective fats, followed by acidulation, water-washing, and stabilization with 50 p.p.m. butylated hydroxyanisole and 50 p.p.m. butylated hydroxy toluene. Palmitic acid was a technical grade prod-
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ers offered evidence to support their view that the phosphatides of the soybean oil might be, in part, responsible for the enhanced utilization of the tallow in their mixtures, it nevertheless seems possible to offer an alternate explanation. It could be that the absorbability of a fat mixture is largely influenced by its content of unsaturated fatty acids, perhaps over a rather range of concentrations. Young and Garrett (1963) showed that unsaturated fatty acids can influence the utilization of saturated fatty acids in mixtures. They found that the digestibility of palmitic acid was greatly increased by mixing it with oleic or, to a lesser extent, by mixing it with linoleic acid. Palmitic and stearic acids, when fed together, tended to depress the absorption of each other. Both oleic and linoleic acids were needed for the maximum absorption of the two saturated fatty acids when fed together. Somewhat related results had been reported from our laboratories (Young, 1961). For instance, only 46% of the stearic acid in beef tallow was absorbed by the fourweek old chick, while the stearic acid in lard was absorbed to the extent of 85%, presumably as a result of the over-all difference in composition of the two fats. If indeed relatively unsaturated fats are able, simply by reason of their unsaturation, to increase the utilizability of saturated fats, then it would be of great interest to know whether fish oil, being highly unsaturated, produces a similar enhancement in utilization. Dansky (1961) attempted to answer this question, but his results were less than wholly conclusive, owing in part, perhaps, to the low level of added fat in his rations and to the fact that he studied mixtures of fish oil with poultry fat and with hydrolyzed animal and vegetable fat. Both of these fats are so well utilized by themselves that it would be difficult to measure any increase in their
996
N. R. ARTMAN
Experiment 1 The restricted feeding technique described by Young and Artman (1961) was modified for comparison of several fats, fatty acids, and mixtures thereof with soybean oil. Chicks were reared for one week on the ration shown in Table 2. Then they were weighed, and the heaviest 10% and the lightest 20%, more or less, were discarded. The remaining birds were allocated in order of decreasing weight randomly to each of the test diets, and within each diet 1
Neo-fat 16, Armour Industrial Chemical Co., Chicago, 111.
group randomly to the pens which were to receive that diet. This procedure ensured that each diet group and each pen contained an assortment of chicks representative (on the basis of body weight at one week) of all the chicks in the experiment. Earlier work had shown a high correlation between finishing weight and weight at one week, and had also shown that this stratification procedure appreciably reduces random variations in the experimental results for experiments of this type. A punched card system was developed to facilitate distribution of the chicks to their treatment groups and pens. For each chick a card was punched with the chick's wing band number and weight. The cards were sorted in order of weight, the upper and lower ends of the deck were discarded, and the deck was cut into sub-decks each of which contained a number of cards equal TABLE 2.—Reference diet used in controlled feeding experiments Ingredient Soybean meal (50% protein) Ground yellow corn Isolated soya protein (ADM-C-1) Fish meal (55% protein) Dehydrated alfalfa meal (17% protein) Dried whole whey (12% protein) Distillers dried solubles DL-methionine Dicalcium phosphate Ground limestone Vitamin mixture #3' Mineral mixture #22 Chromic oxide bread (50% C^Os) Soybean oil
/o 46 11.3 5 5.6 2.2 2.2 2.8 0.3 2.5 1.1 1.1 3.9 1.0 16
1 This amount of vitamin mixture supplied: 440 mg. choline CI (25% concentrate), 110 mg. vitamin B12 concentrate (1.3 mg./lOO g.), 55 mg. stabilized vitamin A (10,000 I.U./g.), 55 mg. dry vitamin E (220 units/g.), 2.2 mg. vitamin D 3 (200,000 I.C.U./g.), 4.4 mg. thiamine, 4.4 mg. niacin, 1.1 mg. Ca pantothenate, 0.44 mg. riboflavin, 0.33 mg. pyridoxine, 0.28 mg. menadione, 0.22 mg. folic acid, 0.033 mg. biotin, and 426.6 mg. glucose per 100 g. diet. 2 This amount of mineral mixture supplied: 0.9 g. iodized NaCl, 1.1 g. KCL, 1.6 g. M G S 0 4 X H 2 0 , 0.04 g. MnSCvH 2 0, 0.04 g. FeS0 4 -7H 2 0, 0.005 g. ZnS0 4 -7H 2 0, 0.002 g. CuSCv5H 2 0, 0.001 g. CoCl 2 -6H 2 0, 0.0001 g. NaMoCv2H 2 0, and 0.12 g. CaC0 3 per 100 g. diet.
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uct1, shown by gas chromatographic analysis to contain 93.1% palmitic acid, 1.4% myristic acid, 4.8% stearic acid, and 0.6% others. Oleic acid was prepared by hydrolysis of olive oil, followed by repeated fractional adductions with urea (Mattson, 1960). It contained 95.1% oleic acid, 3.3% palmitic acid, 0.8% stearic acid, 0.9% linoleic acid. Linoleic acid was prepared from safflower seed oil by similar techniques, and it contained 93.1% linoleic acid, 1.3% palmitic acid, 4.7% oleic acid, and 0.9% linolenic acid. The Arbor Acre White Rock cockerels used in all experiments were purchased at one day of age from a commercial hatchery. They were reared for four weeks in electrically heated wire-floored brooders. From four to eight weeks of age the chicks were kept in wire-floored finishing batteries. The brooders and batteries were kept in windowless rooms maintained at 75-78°F. and 50% relative humidity. Experimental results were subjected to analysis of variance and to Duncan's (1955) multiple range test for significant differences. Wherever appropriate, the experimental variance was partitioned into portions corresponding to individual degrees of freedom.
997
INTERACTIONS OF FATS AND FATTY ACIDS TABLE 3.—Experimental outline and results for experiment 1 Fatty material
Mean 4 week weight1 —g.
10 7 4 0 7 4 7 4 7 4 7 4 7 4 4 4 4 4 4
404 447 c h n 475 e k 523 420 a f 452 d h 439 c g m 473 e k 438 c g m 459 d j 440 e g n 475 e k 435 b g m 468 e j 352 480 k 415 a 427 b f 429 b f m
1 The letters in this table represent the results of treating the data by analysis of variance and Duncan's multiple range test. Any two values which are followed by the same letter (other letters may or may not be shared) are not significantly different at the 5% probability level. Any two values which are not followed by a common letter are significantly different.
to the number of treatment groups in the experiment. The cards of each sub-deck were then randomly allocated to the various groups. A similar sequence assigned the cards in each group to the various pens which comprised the group. Finally the group number and pen number were punched into the cards, the cards were resorted according to wing-band number, and a list was printed from the cards. The list was used as a guide in actually moving the chicks into their assigned pens. Immediately after the chicks were placed in the assigned pens, and for the next 21 days, they were given the experimental rations. Three pens of chicks consumed, ad libitum, the 16% soybean oil reference diet shown in Table 2. The feed consumption rate of these chicks guided the rate at which feed was given to all the other pens. To effect uniformity of feed intake among all the experimental groups, each pen received daily a quantity of feed equal to approximately 95% of the quantity of feed consumed, on the average, by the pens receiv-
ing the reference diet ad libitum. Minor daily adjustments in the quantity of feed given to the experimental pens were sometimes necessary in order to be sure that all feed offered would be consumed within 24 hours. By the end of the experiment each pen had consumed 93.7% as much feed as the mean of the ad libitum pens. The experimental rations were similar to the diet shown in Table 2, but with the test fats, or mixtures of the test fats and cellulose, substituted for the 16% of soybean oil. The fatty materials tested, and their levels in the diets, are shown in Table 3. Each test diet was fed to three pens of eight chicks each. The mean fourth week weights of the chicks receiving the four diets which contained graded levels of soybean oil were plotted against the percent soybean oil in the diets to establish a soybean oil response curve. The soybean oil response curve was linear within experimental error, showing that growth was proportional to the energy contents of the diets. Fats to be tested were fed at levels of 9%
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6% Soybean oil 9% Soybean oil 12% Soybean oil 16% Soybean oil 9% Tallow 12% Tallow 4J% Tallow+4i% Soybean oil 6% Tallow+6% Soybean oil 9% Menhaden oil 12% Menhaden Oil 4 J % Menhaden oil+4J% Soybean oil 6% Menhaden o i l + 6 % Soybean oil 4 i % Menhaden oil+4J% Tallow 6% Menhaden o i l + 6 % Tallow 12% Palmitic Acid 12% Oleic Acid 7£% Palmitic Acid+4J% Oleic Acid 6% Palmitic Acid+6% Oleic Acid 6% Palmitic Acid+6% Linoleic Acid
% Cellulose
998
N. R. ARTMAN
TABLE 4.—Soybean oil equivalents from Experiment 1 Soybean oil equivalentXIOO F a t t y material
Tallow Menhaden oil Tallow:Soybean oil (1:1) Tallow: Menhaden oil (1:1) Menhaden oil: Soybean oil (1:1) Palmitic acid Oleic acid Oleic: Palmitic acids (3:5) Oleic: Palmitic acids (1:1) Linoleic: Palmitic acids (1:1)
Found
Calculated
9 % Level
12% Level
components
78 96 96 92
82 86 97 93
— 89
97
98 10 102 55 63 65
— — — — —
85 96
— — 44 56
—
duced growth greater than the average of the growths produced by the components of the mixture. Experiment 2 The second experiment served to confirm the first and to extend the conclusions derived from it to free fatty acids. The experimental procedure was the same as in Experiment 1; each pen of experimental chicks received 91.4% as much feed as was consumed by the average of the pens receiving the 16% soybean oil diet ad libitum. Some diets were fed to 3 pens of 8 chicks, others to 4 pens. The reference curve for this experiment was obtained by feeding soybean oil at levels of 8%, 11.5%, and 16%, rather than at the previously used levels, in order to concentrate the power of the experiment in the area of greatest interest. Table 5 shows the outline of this experiment, and gives the mean four-week finishing weights of the chicks. The soybean oil equivalent of each fatty material was determined as described above, and these values are given in Table 6. As before the mixtures produced greater growth than the averages of the growths produced by the components of the mixtures. Experiment 3 The third experiment was designed to measure the interaction between tallow and soybean oil more precisely and over a range of compositions. Since earlier experiments had shown that mixtures containing equal weights of tallow and soybean oil were utilized as well as soybean oil alone, it was of particular interest to learn how low the soybean oil:tallow ratio could go before the utilizability of the mixture began to decline. The restricted feeding technique described above was used for this experiment, and the experimental outline is shown in Table 7. Each diet was fed to five pens of eight chicks. Each pen received and con-
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and 12% of the diet. Growth produced by a test fat was compared to the growth produced by soybean oil. All diets were identical, except for the kind and amount of fat and the amount of cellulose which they contained. All experimental groups consumed the same quantity of their respective diets. The soybean oil response curve showed growth to be proportional to the level of dietary soybean oil. The metabolizable and productive energies of the diets, calculated in the usual way, were likewise proportional to the level of soybean oil in the diets, provided cellulose has an energy value of zero. Hence, growth was proportional to the energy values of the diets. The useful energy value of each fatty material fed was expressed as a soybean oil equivalent, obtained by dividing the level of test fat which produced a given level of growth into the level of soybean oil which would have produced the same amount of growth, as interpolated on the soybean oil response curve. Table 3 shows the mean four-week finishing weights of the chicks which received the various fatty materials. The soybean oil equivalents of the various fatty materials are shown in Table 4. The table also shows, for the mixtures, the soybean oil equivalents which the mixtures would have had if the values for the components had been additive. Each of the mixtures pro-
999
INTERACTIONS or FATS AND FATTY ACIDS TABLE 5.—Experimental outline and results for experiment 2 Mean 4 week weight—g.1
% Cellulose
No. of pens per diet
11% Tallow 16% Tallow
5 0
3 4
426 a 464 be
11% Tallow fatty acids 16% Tallow fatty acids
5 0
3 4
396 449
8% Soybean oil 11% Soybean oil 16% Soybean oil
8 5 0
4 4 4
422 a 452 be 496 e
11% Soybean oil fatty acids 16% Soybean oil fatty acids
5 0
3 4
467 492
5 1 % Soybean fatty acids+51% tallow 8% Soybean fatty acids+8% tallow
5 0
3 4
454 be e 502
5J% Soybean o i l + 5 1 % tallow fatty acids 8% Soybean o i l + 8 % tallow fatty acids
5 0
3 4
442 ab 489
5 1 % Soybean oil fatty acids+51% tallow fatty acids 8% Soybean oil fatty acids+8% tallow fatty acids
5 0
3 4
456 487
5 1 % Soybean o i l + 5 1 % tallow 8% Soybean o i l + 8 % tallow
5 0
3 4
448 be e 501
Fatty material
cd e
e
be de
See footnote 1, Table 3.
sumed 92.5% as much feed as was consumed by the average of three pens receiving the 16% soybean oil diet ad libitum. Table 7 also shows the mean weights of the chicks at four weeks of age. Although none of the fat mixtures gave results significantly different from mixtures having neighboring compositions, when fed at either the 11% or the 16% level, detailed partitioning of the variance showed that the mixtures containing 50% and 100%
soybean oil gave results highly significantly (P < 0.01) different from mixtures containing 25% and 37^2% soybean oil. Differences between the latter two mixtures and the mixtures containing 0% and 12^2% soybean oil were likewise highly significant. The soybean oil equivalents determined from the above data are shown in Table 8, together with the values calculated from the components.
TABLE 6.—Soybean oil equivalents from experiment 2 Soybean oil equivalentsX 100
11% Level
16% Level
Average
Calculated from components
76 49 115 97 91 102 105
78 67 97 104 95 104 94
77 58 106 100 93 103 98
88 79 92 82
Fatty material
Tallow Tallow fatty acids Soybean oil fatty acids Soybean oil:Tallow (1:1) Soybean oil:Tallow fatty acids (1:1) Soybean oil fatty acids:Tallow (1:1) Soybean oil fatty acids:Tallow fatty acids (1:1)
Found
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1
be
1000
N. R. ARTMAN
TABLE 7.-—Experimental
outline and results for experiment 3
Soybean oil% 16 8 6 4 2 0 11
s.s
1
% 0 8 10 12 14 16 0 5.5 6.875 8.25 9.625 11 0
%
Mean 4 week weight g-1
0 0 0 0 0 0 5 5 5 5 5 5 8
504 ab 510 a 497 be 499 b 484 cd 478 de 462 e 449 ef 450 ef 443 fg 438 fg 435 g 415
Cellulose
See footnote 1, Table 3.
Experiment 4 This experiment was designed to show whether the conclusions reached on the basis of the above controlled feeding experiments are valid under ad libitum feeding conditions, according to the more generally recognized criteria of growth, feed efficiency fat digestibility, and metabolizable energy. Sixteen fats, fatty acids, and mixtures thereof were prepared as listed in the experimental outline, Table 9. The fatty materials were incorporated at the 15% level into the ration shown in Table 10. In order to attain the desired precision in the measurements of growth and feed efficiency, two substantially identical experiments, designated 4A and 4B respectively, were carried out, one after the other. In each experiment, each of the sixteen diets was fed to three pens of ten Arbor Acre White Rock cockerels, starting at one day of age, for eight weeks. Chromic oxide bread was included in all diets, and during the third week of the first experiment fecal collections were made. Fecal samples were processed and analyzed as described previously (Young, 1961) to afford data for calculating fat digestibility and metabolizable energy. The M.E. values were calculated, not
DISCUSSION
If the growth-promoting properties of fatty materials were additive, then the numbers in the third column of Table 4 should have agreed with the numbers in the first and second columns. Since the calculated values are smaller than the values actually found, it is apparent that mixtures of tallow with menhaden oil or soybean oil gave better growth than would have been expected on the basis of the TABLE 8.—Soybean oil equivalents from experiment 3 % Soybean oil in tallowsoybean oil blend 50 37i 25 12| 0
Soyt >ean oil equivalentXIOO Found 11% Level 93 93 89 86 84
16% Level 104 95 97 86 81
Calculated Mean
components
98 94 93 86 83
92 89 87 85
—
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4.125 2.75 1.375 0 8
Tallow
in the usual way, by comparing the M.E. values of diets containing the test fats with the M.E. value of a reference diet containing glucose, but rather by comparing the test fats with soybean oil, the digestibility and M.E. of which have already been carefully measured (Young and Artman, 1961). The metabolizable energy values were corrected for nitrogen retention. Results of the experiment are shown in Table 9. The weight and feed efficiency values for each replication are given together with their averages over the two trials. Results of the two runs differed slightly but significantly; in the second run the weights were generally higher and the feed per gain ratios lower than in the first. There were no significant interactions between replication and any other experimental factors. Variation between replications was taken into account in the analysis of variance.
Soybean oil Acidulated soybean oil soapstock Soybean oil fatty acids Menhaden oil Tallow (prime beef) Tallow fatty acids Soybean o i l + 7 i % tallow Soybean oil+111% tallow Soybean o i l + 7 J % tallow fatty acids Soybean oil soapstock+7i% tallow Soybean oil s o a p s t o c k + l l | % tallow Soybean oil soapstock+7|% tallow fatty acids Soybean oil fatty acids+7^% tallow Soybean oil fatty acids+7J% tallow fatty acids Menhaden o i l + 7 | % tallow Menhaden oil+7J% tallow fatty acids 1,450 1,506 1,471
1,442 1,535 1,419 28.9
461 518
1,439 1,504
34.9
1,537 1,495 1,464 1,099 1,532 1,480 1,548 1,530 1,523 1,543 1,524
1,520 1,432 1,455 1,080 1,545 1,417 1,504 1,556 1,522 1,504 1,502
Expt. 4A Expt. 4B
d cd d cd cd bed
b
cd be be
1
21.3
1,446 1,520 1,445
b cd b
1,450 b 1,511 bed
1,529 1,463 1,460 1,090 1,538 1,448 1,526 1,543 1,522 1,524 1,513
Mean
8 Week weight—g.
0.022
.81 .81 .89
.89 .81
.74 .85 .84 .04 .86 .98 .76 .81 .83 .81 .85
0.017
1.82 1.80 1.86
1.85 1.80
1.72 1.83 1.78 2.04 1.89 1.91 1.75 1.80 1.78 1.80 1.82
Expt. 4A Expt. 4B
0.014
1.82 1.81 1.88
1.88 1.81
be b d
b
d
1.74 a 1.85 bed 1.82 be f 2.04 1.88 d 1.95 e 1.76 a 1.81 b 1.81 b 1.81 b 1.84 bed
Mean
1
8 Week feed/Gain ratio
1.26
78.3 83.5 75.9
74.9 84.7
ef bed f
be
f
95.6 a 86.2 be 93.8 a 96.2 a 68.4 g 56.9 h 87.1 b 80.0 de 80.2 de 83.0 cd 77.9 ef
%„2
Fat digestibility
0.21
7.70 8.21 7.74
7.57 8.50
9.07 8.13 8.83 9.25 7.32 6.01 8.71 8.34 8.40 7.99 7.86
efg efg
bedef
bed
fg
bede bede defg defg
abc
g h
cdef
ab a
a
Fat metabolizable energy Cal./g. 1 ' 2
2
See footnote 1, Table 3. Soybean oil was taken as the reference for determinations of fat digestibility and metabolizable energy. The values shown for it were determined in previous work.
1
Standard Error of the Means
H% 7|%
7\% 7J%
15% 15% 15% 15% 15% 15% 7i% 3|% 7|% 7J% 3|% 7J%
Added fats
TABLE 9.—Experimental outline and results for experiment 4
from http://ps.oxfordjournals.org/ at Simon Fraser University on June 4, 2015 O
o
>< >
H H
>
o
>
w
> H
O *i
%
H O
> O
H W W
%
1002
N. R. ARTMAN
TABLE 10.—Diet formulation for experiment 4 Ingredient Soybean meal (50% protein) Ground yellow corn Fish meal (55% protein) Meat scrap Distillers dried solubles Dehydrated alfalfa meal Dicalcium phosphate Ground limestone Mineral and penicillin mixture 1 Vitamin mixture A2 Chromic oxide bread (50% Cr2Os) Fat
% 30.50 34.15 6.00 6.50 2.50 2.00 0.60 0.55 0.60 0.60 1.00 15.00
growth responses produced by these fats individually, and likewise that the performance of palmitic acid was improved by mixing it with oleic acid. Although pure linoleic acid was not fed, a mixture of linoleic and palmitic acids gave the same results as a mixture of oleic and palmitic acids. It appears that oleic and linoleic acids are similar in their ability to enhance the utilization of palmitic acid, at least under the conditions of this experiment in which natural ingredients in the diet supplied appreciable quantities of both oleic and linoleic acids. These results strongly support the view that relatively unsaturated fats are able to increase the utilizability of relatively saturated fats. The second experiment showed that the same effects occur whether the relatively saturated and the relatively unsaturated components are supplied both as neutral triglycerides, both as free fatty acids, or as mixtures of triglycerides and fatty acids. The third experiment confirmed that a mixture of equal parts of tallow and soybean oil is nearly equivalent to soybean oil alone in its ability to promote growth under con-
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1 This amount of mineral and penicillin mixture supplied: 500 mg. iodized salt, 31 mg. MnSCu-FtO, 69 mg. penicillin in limestone per 100 g. of diet. 2 This amount of vitamin mixture supplied: 344 mg. choline chloride (25% concentrate), 0.33 mg. riboflavin, 1.10 mg. calcium pantothenate, 3.3 mg. niacin, 65.6 mg. B12 concentrate (6 mg./lb.), 49.9 mg. methionine, 110 mg. vitamin A (10,000 I.U./g.), 0.55 mg. vitamin D 3 (250,000 I.C.U./g.), and 25 mg. ground corn per 100 g. of diet.
ditions of equalized feed intake, but that further dilutions of the soybean oil with tallow result in diminutions of the growthpromoting power of the mixture. When the mixture contained only 12^>% soybean oil, the difference between its growth-promoting ability and the growth-promoting ability calculated for it on the basis of its components was too small to measure; that is, the utilizability of the tallow component was not increased enough to be measured in an experiment of this size. When the mixture contained 25% soybean oil, however, there was enhancement of its energy value, and the utilizability of the tallow component appears to have been increased. From a plot of soybean oil equivalents versus percent soybean oil in the soybean oil-tallow mixtures, it can be seen that the mixtures are better utilized than is tallow alone. Within the area of uncertainty attendant upon the experimental error the extent of enhancement is proportional to the soybean oil content, over the range of 0 to 50% soybean oil. Thus, the addition of a given percentage of soybean oil to tallow apparently leads, not only to the expected high utilization of the soybean oil itself, but to equally good utilization of a portion of the tallow equal in weight to the weight of the soybean oil added. In general the results of the fourth experiment, which employed ad libitum feeding, confirmed the results of the three restricted feeding experiments. Mixtures of soybean oil, acidulated soapstock from soybean oil refining, or soybean oil fatty acids with tallow or tallow fatty acids gave results better than the averages calculated for these mixtures of animal and vegetable stocks, as measured by feed efficiency, absorbability, or metabolizable energy. This was true for all of the mixtures tested, as a group, and for most of the individual mixtures. The extent to which the metabolizable
1003
INTERACTIONS OF FATS AND FATTY ACIDS TABLE 11.—Comparison of experimental findings Restricted feeding results Expt. 1
Expt. 2
Expt. 3
SBO SBO fatty acid Tallow Tallow fatty acid SBO+tallow (1:1) SBO+tallow (1:3) SBO+tallow fatty acids (1:1) SBO fatty acids +tallow(l: 1) SBO fatty acids+tallow fatty acids (1:1)
100
100 106 76 57 100
100
79 96
ME ratio
Digestibility ratio
93 103
100 96 80 65 95 91 92 93
100 98 72 58 91 84 84 89
100 96 93 89 99 96 96 96
99
84
82
96
energy values of the tallow and tallow fatty acids were enhanced by admixture with intact or hydrolyzed soybean oil appeared to be approximately proportional to the level of the soybean oil stocks in the mixtures. The various fats tested gave widely ranging values for feed efficiency, digestibility, and metabolizable energy; nevertheless, for any given fat all three of these values corresponded closely with each other, and all appeared to be valid measurements of the nutritive value of different kinds of fat. Insofar as comparisons can be made, both the restricted feeding experiments and the ad libitum feeding test gave similar results. Table 11 shows this comparison in detail. The first three columns are averages of soybean oil equivalents found in Experiments 1-3. The next three columns are results from Experiment 4 expressed as ratios of metabolizable energy, digestibility, and feed efficiency (gain/ feed) of the test fats to the corresponding values for soybean oil. All values in the table have been multiplied by 100 for easier reading. In general the various sets of values are in good agreement. The feed efficiency values cover a much shorter range than the other values. This is to be expected since they represent the feed efficiencies of the entire rations, whereas the other values rep-
83 98 93
Jj^L, ^ ^
resent the values of only the variable portion of the rations, that is, the fats. It is interesting that the soybean oil equivalents, which are based on chick growth, tend, in general, to be somewhat higher than the values based merely on the disappearance of fat and energy from feed material as it passes through the digestive tract. This discrepancy may be related to special extra-caloric growth-promoting properties of fats and oils which have been postulated by some workers (Dam et al, 1959); the restricted feeding results would seem to be more closely related to productive energy than are the digestibility and M.E. values, and to be more meaningful measurements of the property which has the greatest economic significance for the poultry producer, namely the cost of producing a pound of marketable meat. The results for menhaden oil are unique and anomolous, both in Experiment 2 and in Experiment 4. As would be expected for so unsaturated a fat, it has high digestibility and M.E. values. When fed at levels of 4J/2% to 9% of the diet, it promoted good growth and feed efficiency, quite in keeping with its high digestibility. At a level of 12 % (Experiment 1) it led to poorer growth than would have been expected, showing a soybean oil equivalent of only .86, rather than .96 as it did at the 9% level. At the
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Fat
Ad libitmn feeding results expt. 4
1004
N. R. ARTMAN
SUMMARY
Mixtures of fats and fatty acids having different degrees of unsaturation were evaluated and compared as energy sources for the chick in three controlled or restricted feeding tests, in which growth was proportional to the energy value of the fat, and one conventional eight-week test, in which growth, feed efficiency, digestibility, and metabolizable energy were measured. The following conclusions were reached: 1. The utilizability of relatively saturated fats or fatty acids is increased by mixing them with relatively unsaturated fats or fatty acids. 2. Successive increments of relatively unsaturated fat, added to a relatively saturated fat, effect successively smaller increases in the utilizability of the relatively saturated fat. 3. Although menhaden fish oil is well utilized, and mixtures of it with other fat produce good growth and feed efficiency, at high levels it tends to suppress chick growth. 4. The controlled feeding technique gives results in substantial agreement with more conventional measurements
of fat utilizability. The controlled feeding technique has the advantage of quickly comparing different fats under conditions which essentially evaluate their productive energy values. REFERENCES Dangoumau, A., and H Debruyne, 1963. Utilisation des huiles obtenues par esterification des acides gras distilles pour l'enrichissement des rations pour poulets de chair. Revue Francaise des Corps Gras, 10: 259-271. Dansky, L. M., 1961. The growth promoting properties of menhaden fish oil as influenced by various fats. Poultry Sci. 41: 1352-1354. Dam, R., R. M. Leach, Jr., T. S. Nelson, L. C. Norris and F. W. Hill, 1959. Studies on the effect of quantity and type of fat on chick growth. J. Nutrition, 68: 615-632. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Mattson, F. H., 1960. An investigation of the essential fatty acid activity of some geometrical isomers of unsaturated fatty acids. J. Nutrition, 71: 366-370. Pepper, W. F., S. J. Slinger and I. R. Sibbald, 1962. A comparison of feed grade tallow and a mixture of tallow and acidulated soapstocks in practical chicken roaster rations. Poultry Sci. 41: 11631168. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1960. A synergistic relationship between tallow and undegummed soybean oil. Poultry Sci. 39: 1295. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961. Factors affecting the metabolizable energy of content of poultry feeds. 2. Variability in the M.E. values attributed to samples of tallow and undegummed soybean oil. Poultry Sci. 40: SOSSOS. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1962. The utilization of a number of fats, fatty materials and mixtures thereof evaluated in terms of metabolizable energy, chick weight gains and gain: feed ratios. Poultry Sci. 41: 46-61. Young, R. J., 1961. The energy value of fats and fatty acids for chicks. 1. Metabolizable energy. Poultry Sci. 41: 1225-1233. Young, R. J., and N. R. Artman, 1961. The energy value of fats and fatty acids for chicks. 2. Evaluated by controlled feed intake. Poultry Sci. 40: 1653-1662. Young, R. J. and R. L. Garrett, 1963. The effect of oleic and linoleic acids on the absorption of saturated fatty acids in the chick. J. Nutrition, 81: 321-329.
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15% level (Experiment 4) it gave very much poorer growth and feed efficiency than any other of the fats tested. Mixtures of fish oil with tallow or tallow fatty acids were nearly as good, by the criteria examined, as mixtures of soybean oil with tallow or tallow fatty acids, but there was no suggestion that fish oil increased the metabolizable energy or digestibility of tallow or tallow fatty acids. All in all, it appears that the fish oil contains a factor or quality, or perhaps a deficiency, which causes it to interfere with the proper utilization of absorbed energy by the chick, when it is fed at levels as high as 12 to 15%. That this interfering factor is related to the oxidative instability of the oil is a reasonable assumption but, at present, no more than that.
G. MADIEDO, E.
F. RICHTER AND M.
L.
SUNDE
REFERENCES
Several procedures for analyzing feedstuffs for xanthophyll were used. All the feedstuffs analyzed were fed to laying hens, and the values obtained by chemical assay were compared with the biological results. The following extraction procedures were found to give values which agree fairly well with the biological results:
Bickoff, E. M., A. L. Livingston, G. F. Bailey and C. R. Thompson, 1954. Xanthophyll determination in dehydrated alfalfa meal. J. Assoc. Off. Agric. Chem. 37: 894-902. Brambila, S., J. A. Pino and C. Mendoza, 1962. Studies with a natural source of xanthophylls for the pigmentation of egg yolks and skin of poultry. Poultry Sci. 41: 1629. Heiman, V., and J. S. Carver, 1935. The yolk color index. U. S. Egg Poultry Magazine, 41(8): 40-41. Jenson, A., 1963. The effect of several carotenoids on egg yolk coloration. Poultry Sci. 42: 912-916. Madiedo, G., and M. L. Sunde, 1964. The effect of algae, dried lake weed, alfalfa and ethoxyquin on yolk color. Poultry Sci. 43: 1056-1061. Morehouse, A. L., 1962. Personal communication. Morehouse, A. L., and A. W. Hanson, 1961. Pigmentation studies with dried algae meal. Informal Poultry Nutr. Conf., Atlantic City, N. J. Quackenbush, F. W., J. G. Firch, W. J. Rabourn, M. McQuistan, E. N. Petzold and T. E. Kargl, 1961. Analysis of carotenoids in corn grain. J. Agr. Food Chem. 9: 132-35.
Corn:
Saponification with alcoholic potassium hydroxide and extraction with petroleum ether.
Algae:
Saponification with alcoholic potassium hydroxide and extraction with ethyl ether.
Marigold petals: Direct extract on with chloroform. Alfalfa meal: Overnight extraction with an acetone-hexane mixture.
Interactions of Fats and Fatty Acids as Energy Sources for the Chick N E I L R.
ARTMAN
The Procter &* Gamble Company, Miami Valley Laboratories, Cincinnati 39, Ohio (Received for publication February 7, 1964)
ATS and fatty acids, like other feedstuff ingredients used as energy sources for the growing chick, have been assigned metabolizable energy (M.E.) values which are widely used in the formulation of rations. Experimental findings by Sibbald et al. (1960, 1961) seemed to raise doubts, however, about the applicability of published M.E. values for individual fatty substances in mixtures of different kinds of fats. They found that a 50/50 mixture by weight of soybean oil, having an M.E. value of 8.46 Cal./g., and tallow, M.E. 6.94 Cal./g., had an M.E. value of 8.41 Cal./g. Simple arithmetic indicated that
F
the M.E. of the tallow in the mixture must have ben raised to 8.36 Cal./g., and it was postulated that the non-degummed soybean oil might have contained a factor, such as phospholipids, which increased the digestibility of the tallow. Although other reports (Pepper et al., 1962; Dangoumau and Debruyne, 1963) have failed to show any advantages gained by mixing different kinds of fat, a recent publication by Sibbald et al. (1962) suggested that some samples of so-called tallow are more susceptible than others to having their M.E. values raised by admixture with soybean oil. Although these work-
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SUMMARY
995
INTERACTIONS OF FATS AND FATTY ACIDS
TABLE 1.—Fats used in feeding studies Fat Soybean oil (Refined & bleached) Soybean oil fatty acids Prime beef tallow Tallow fatty acids Acidulated soapstock from soybean oil refining Menhaden fish oil
Saponification value
Acid value
Iodine value
193 198 196 204
0.1 195 0.7 203
130 135 43.8 45.5
187 193
75 1.4
128 151
utilization resulting from admixture of them with fish oil. In the work to be reported here, four experiments were carried out in order (a) to verify the original observations of Sibbald et al., (b) to extend them, if possible, to other types of fatty material, especially free fatty acids, and (c) to determine whether fish oil, like soybean oil, is able to increase the utilizability of tallow. Comparisons of fat utilizability by conventional techniques are expensive and time-comsuming. A simpler method, based on controlled feed intake, has been described (Young and Artman, 1961), but its validity has been tested in relatively few published experiments. Hence, a further, although incidental, purpose of this work was to compare the evaluation of fatty materials by the controlled feeding method with evaluation by measurements of growth, feed efficiency, digestibility, and metabolizable energy. EXPERIMENTAL MATERIALS AND TECHNIQUES
The fats and fatty acids fed in the various experiments were characterized by the analytical values shown in Table 1. The soybean oil fatty acids and tallow fatty acids were prepared by alkaline hydrolysis of the respective fats, followed by acidulation, water-washing, and stabilization with 50 p.p.m. butylated hydroxyanisole and 50 p.p.m. butylated hydroxy toluene. Palmitic acid was a technical grade prod-
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ers offered evidence to support their view that the phosphatides of the soybean oil might be, in part, responsible for the enhanced utilization of the tallow in their mixtures, it nevertheless seems possible to offer an alternate explanation. It could be that the absorbability of a fat mixture is largely influenced by its content of unsaturated fatty acids, perhaps over a rather range of concentrations. Young and Garrett (1963) showed that unsaturated fatty acids can influence the utilization of saturated fatty acids in mixtures. They found that the digestibility of palmitic acid was greatly increased by mixing it with oleic or, to a lesser extent, by mixing it with linoleic acid. Palmitic and stearic acids, when fed together, tended to depress the absorption of each other. Both oleic and linoleic acids were needed for the maximum absorption of the two saturated fatty acids when fed together. Somewhat related results had been reported from our laboratories (Young, 1961). For instance, only 46% of the stearic acid in beef tallow was absorbed by the fourweek old chick, while the stearic acid in lard was absorbed to the extent of 85%, presumably as a result of the over-all difference in composition of the two fats. If indeed relatively unsaturated fats are able, simply by reason of their unsaturation, to increase the utilizability of saturated fats, then it would be of great interest to know whether fish oil, being highly unsaturated, produces a similar enhancement in utilization. Dansky (1961) attempted to answer this question, but his results were less than wholly conclusive, owing in part, perhaps, to the low level of added fat in his rations and to the fact that he studied mixtures of fish oil with poultry fat and with hydrolyzed animal and vegetable fat. Both of these fats are so well utilized by themselves that it would be difficult to measure any increase in their
996
N. R. ARTMAN
Experiment 1 The restricted feeding technique described by Young and Artman (1961) was modified for comparison of several fats, fatty acids, and mixtures thereof with soybean oil. Chicks were reared for one week on the ration shown in Table 2. Then they were weighed, and the heaviest 10% and the lightest 20%, more or less, were discarded. The remaining birds were allocated in order of decreasing weight randomly to each of the test diets, and within each diet 1
Neo-fat 16, Armour Industrial Chemical Co., Chicago, 111.
group randomly to the pens which were to receive that diet. This procedure ensured that each diet group and each pen contained an assortment of chicks representative (on the basis of body weight at one week) of all the chicks in the experiment. Earlier work had shown a high correlation between finishing weight and weight at one week, and had also shown that this stratification procedure appreciably reduces random variations in the experimental results for experiments of this type. A punched card system was developed to facilitate distribution of the chicks to their treatment groups and pens. For each chick a card was punched with the chick's wing band number and weight. The cards were sorted in order of weight, the upper and lower ends of the deck were discarded, and the deck was cut into sub-decks each of which contained a number of cards equal TABLE 2.—Reference diet used in controlled feeding experiments Ingredient Soybean meal (50% protein) Ground yellow corn Isolated soya protein (ADM-C-1) Fish meal (55% protein) Dehydrated alfalfa meal (17% protein) Dried whole whey (12% protein) Distillers dried solubles DL-methionine Dicalcium phosphate Ground limestone Vitamin mixture #3' Mineral mixture #22 Chromic oxide bread (50% C^Os) Soybean oil
/o 46 11.3 5 5.6 2.2 2.2 2.8 0.3 2.5 1.1 1.1 3.9 1.0 16
1 This amount of vitamin mixture supplied: 440 mg. choline CI (25% concentrate), 110 mg. vitamin B12 concentrate (1.3 mg./lOO g.), 55 mg. stabilized vitamin A (10,000 I.U./g.), 55 mg. dry vitamin E (220 units/g.), 2.2 mg. vitamin D 3 (200,000 I.C.U./g.), 4.4 mg. thiamine, 4.4 mg. niacin, 1.1 mg. Ca pantothenate, 0.44 mg. riboflavin, 0.33 mg. pyridoxine, 0.28 mg. menadione, 0.22 mg. folic acid, 0.033 mg. biotin, and 426.6 mg. glucose per 100 g. diet. 2 This amount of mineral mixture supplied: 0.9 g. iodized NaCl, 1.1 g. KCL, 1.6 g. M G S 0 4 X H 2 0 , 0.04 g. MnSCvH 2 0, 0.04 g. FeS0 4 -7H 2 0, 0.005 g. ZnS0 4 -7H 2 0, 0.002 g. CuSCv5H 2 0, 0.001 g. CoCl 2 -6H 2 0, 0.0001 g. NaMoCv2H 2 0, and 0.12 g. CaC0 3 per 100 g. diet.
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uct1, shown by gas chromatographic analysis to contain 93.1% palmitic acid, 1.4% myristic acid, 4.8% stearic acid, and 0.6% others. Oleic acid was prepared by hydrolysis of olive oil, followed by repeated fractional adductions with urea (Mattson, 1960). It contained 95.1% oleic acid, 3.3% palmitic acid, 0.8% stearic acid, 0.9% linoleic acid. Linoleic acid was prepared from safflower seed oil by similar techniques, and it contained 93.1% linoleic acid, 1.3% palmitic acid, 4.7% oleic acid, and 0.9% linolenic acid. The Arbor Acre White Rock cockerels used in all experiments were purchased at one day of age from a commercial hatchery. They were reared for four weeks in electrically heated wire-floored brooders. From four to eight weeks of age the chicks were kept in wire-floored finishing batteries. The brooders and batteries were kept in windowless rooms maintained at 75-78°F. and 50% relative humidity. Experimental results were subjected to analysis of variance and to Duncan's (1955) multiple range test for significant differences. Wherever appropriate, the experimental variance was partitioned into portions corresponding to individual degrees of freedom.
997
INTERACTIONS OF FATS AND FATTY ACIDS TABLE 3.—Experimental outline and results for experiment 1 Fatty material
Mean 4 week weight1 —g.
10 7 4 0 7 4 7 4 7 4 7 4 7 4 4 4 4 4 4
404 447 c h n 475 e k 523 420 a f 452 d h 439 c g m 473 e k 438 c g m 459 d j 440 e g n 475 e k 435 b g m 468 e j 352 480 k 415 a 427 b f 429 b f m
1 The letters in this table represent the results of treating the data by analysis of variance and Duncan's multiple range test. Any two values which are followed by the same letter (other letters may or may not be shared) are not significantly different at the 5% probability level. Any two values which are not followed by a common letter are significantly different.
to the number of treatment groups in the experiment. The cards of each sub-deck were then randomly allocated to the various groups. A similar sequence assigned the cards in each group to the various pens which comprised the group. Finally the group number and pen number were punched into the cards, the cards were resorted according to wing-band number, and a list was printed from the cards. The list was used as a guide in actually moving the chicks into their assigned pens. Immediately after the chicks were placed in the assigned pens, and for the next 21 days, they were given the experimental rations. Three pens of chicks consumed, ad libitum, the 16% soybean oil reference diet shown in Table 2. The feed consumption rate of these chicks guided the rate at which feed was given to all the other pens. To effect uniformity of feed intake among all the experimental groups, each pen received daily a quantity of feed equal to approximately 95% of the quantity of feed consumed, on the average, by the pens receiv-
ing the reference diet ad libitum. Minor daily adjustments in the quantity of feed given to the experimental pens were sometimes necessary in order to be sure that all feed offered would be consumed within 24 hours. By the end of the experiment each pen had consumed 93.7% as much feed as the mean of the ad libitum pens. The experimental rations were similar to the diet shown in Table 2, but with the test fats, or mixtures of the test fats and cellulose, substituted for the 16% of soybean oil. The fatty materials tested, and their levels in the diets, are shown in Table 3. Each test diet was fed to three pens of eight chicks each. The mean fourth week weights of the chicks receiving the four diets which contained graded levels of soybean oil were plotted against the percent soybean oil in the diets to establish a soybean oil response curve. The soybean oil response curve was linear within experimental error, showing that growth was proportional to the energy contents of the diets. Fats to be tested were fed at levels of 9%
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6% Soybean oil 9% Soybean oil 12% Soybean oil 16% Soybean oil 9% Tallow 12% Tallow 4J% Tallow+4i% Soybean oil 6% Tallow+6% Soybean oil 9% Menhaden oil 12% Menhaden Oil 4 J % Menhaden oil+4J% Soybean oil 6% Menhaden o i l + 6 % Soybean oil 4 i % Menhaden oil+4J% Tallow 6% Menhaden o i l + 6 % Tallow 12% Palmitic Acid 12% Oleic Acid 7£% Palmitic Acid+4J% Oleic Acid 6% Palmitic Acid+6% Oleic Acid 6% Palmitic Acid+6% Linoleic Acid
% Cellulose
998
N. R. ARTMAN
TABLE 4.—Soybean oil equivalents from Experiment 1 Soybean oil equivalentXIOO F a t t y material
Tallow Menhaden oil Tallow:Soybean oil (1:1) Tallow: Menhaden oil (1:1) Menhaden oil: Soybean oil (1:1) Palmitic acid Oleic acid Oleic: Palmitic acids (3:5) Oleic: Palmitic acids (1:1) Linoleic: Palmitic acids (1:1)
Found
Calculated
9 % Level
12% Level
components
78 96 96 92
82 86 97 93
— 89
97
98 10 102 55 63 65
— — — — —
85 96
— — 44 56
—
duced growth greater than the average of the growths produced by the components of the mixture. Experiment 2 The second experiment served to confirm the first and to extend the conclusions derived from it to free fatty acids. The experimental procedure was the same as in Experiment 1; each pen of experimental chicks received 91.4% as much feed as was consumed by the average of the pens receiving the 16% soybean oil diet ad libitum. Some diets were fed to 3 pens of 8 chicks, others to 4 pens. The reference curve for this experiment was obtained by feeding soybean oil at levels of 8%, 11.5%, and 16%, rather than at the previously used levels, in order to concentrate the power of the experiment in the area of greatest interest. Table 5 shows the outline of this experiment, and gives the mean four-week finishing weights of the chicks. The soybean oil equivalent of each fatty material was determined as described above, and these values are given in Table 6. As before the mixtures produced greater growth than the averages of the growths produced by the components of the mixtures. Experiment 3 The third experiment was designed to measure the interaction between tallow and soybean oil more precisely and over a range of compositions. Since earlier experiments had shown that mixtures containing equal weights of tallow and soybean oil were utilized as well as soybean oil alone, it was of particular interest to learn how low the soybean oil:tallow ratio could go before the utilizability of the mixture began to decline. The restricted feeding technique described above was used for this experiment, and the experimental outline is shown in Table 7. Each diet was fed to five pens of eight chicks. Each pen received and con-
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and 12% of the diet. Growth produced by a test fat was compared to the growth produced by soybean oil. All diets were identical, except for the kind and amount of fat and the amount of cellulose which they contained. All experimental groups consumed the same quantity of their respective diets. The soybean oil response curve showed growth to be proportional to the level of dietary soybean oil. The metabolizable and productive energies of the diets, calculated in the usual way, were likewise proportional to the level of soybean oil in the diets, provided cellulose has an energy value of zero. Hence, growth was proportional to the energy values of the diets. The useful energy value of each fatty material fed was expressed as a soybean oil equivalent, obtained by dividing the level of test fat which produced a given level of growth into the level of soybean oil which would have produced the same amount of growth, as interpolated on the soybean oil response curve. Table 3 shows the mean four-week finishing weights of the chicks which received the various fatty materials. The soybean oil equivalents of the various fatty materials are shown in Table 4. The table also shows, for the mixtures, the soybean oil equivalents which the mixtures would have had if the values for the components had been additive. Each of the mixtures pro-
999
INTERACTIONS or FATS AND FATTY ACIDS TABLE 5.—Experimental outline and results for experiment 2 Mean 4 week weight—g.1
% Cellulose
No. of pens per diet
11% Tallow 16% Tallow
5 0
3 4
426 a 464 be
11% Tallow fatty acids 16% Tallow fatty acids
5 0
3 4
396 449
8% Soybean oil 11% Soybean oil 16% Soybean oil
8 5 0
4 4 4
422 a 452 be 496 e
11% Soybean oil fatty acids 16% Soybean oil fatty acids
5 0
3 4
467 492
5 1 % Soybean fatty acids+51% tallow 8% Soybean fatty acids+8% tallow
5 0
3 4
454 be e 502
5J% Soybean o i l + 5 1 % tallow fatty acids 8% Soybean o i l + 8 % tallow fatty acids
5 0
3 4
442 ab 489
5 1 % Soybean oil fatty acids+51% tallow fatty acids 8% Soybean oil fatty acids+8% tallow fatty acids
5 0
3 4
456 487
5 1 % Soybean o i l + 5 1 % tallow 8% Soybean o i l + 8 % tallow
5 0
3 4
448 be e 501
Fatty material
cd e
e
be de
See footnote 1, Table 3.
sumed 92.5% as much feed as was consumed by the average of three pens receiving the 16% soybean oil diet ad libitum. Table 7 also shows the mean weights of the chicks at four weeks of age. Although none of the fat mixtures gave results significantly different from mixtures having neighboring compositions, when fed at either the 11% or the 16% level, detailed partitioning of the variance showed that the mixtures containing 50% and 100%
soybean oil gave results highly significantly (P < 0.01) different from mixtures containing 25% and 37^2% soybean oil. Differences between the latter two mixtures and the mixtures containing 0% and 12^2% soybean oil were likewise highly significant. The soybean oil equivalents determined from the above data are shown in Table 8, together with the values calculated from the components.
TABLE 6.—Soybean oil equivalents from experiment 2 Soybean oil equivalentsX 100
11% Level
16% Level
Average
Calculated from components
76 49 115 97 91 102 105
78 67 97 104 95 104 94
77 58 106 100 93 103 98
88 79 92 82
Fatty material
Tallow Tallow fatty acids Soybean oil fatty acids Soybean oil:Tallow (1:1) Soybean oil:Tallow fatty acids (1:1) Soybean oil fatty acids:Tallow (1:1) Soybean oil fatty acids:Tallow fatty acids (1:1)
Found
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1
be
1000
N. R. ARTMAN
TABLE 7.-—Experimental
outline and results for experiment 3
Soybean oil% 16 8 6 4 2 0 11
s.s
1
% 0 8 10 12 14 16 0 5.5 6.875 8.25 9.625 11 0
%
Mean 4 week weight g-1
0 0 0 0 0 0 5 5 5 5 5 5 8
504 ab 510 a 497 be 499 b 484 cd 478 de 462 e 449 ef 450 ef 443 fg 438 fg 435 g 415
Cellulose
See footnote 1, Table 3.
Experiment 4 This experiment was designed to show whether the conclusions reached on the basis of the above controlled feeding experiments are valid under ad libitum feeding conditions, according to the more generally recognized criteria of growth, feed efficiency fat digestibility, and metabolizable energy. Sixteen fats, fatty acids, and mixtures thereof were prepared as listed in the experimental outline, Table 9. The fatty materials were incorporated at the 15% level into the ration shown in Table 10. In order to attain the desired precision in the measurements of growth and feed efficiency, two substantially identical experiments, designated 4A and 4B respectively, were carried out, one after the other. In each experiment, each of the sixteen diets was fed to three pens of ten Arbor Acre White Rock cockerels, starting at one day of age, for eight weeks. Chromic oxide bread was included in all diets, and during the third week of the first experiment fecal collections were made. Fecal samples were processed and analyzed as described previously (Young, 1961) to afford data for calculating fat digestibility and metabolizable energy. The M.E. values were calculated, not
DISCUSSION
If the growth-promoting properties of fatty materials were additive, then the numbers in the third column of Table 4 should have agreed with the numbers in the first and second columns. Since the calculated values are smaller than the values actually found, it is apparent that mixtures of tallow with menhaden oil or soybean oil gave better growth than would have been expected on the basis of the TABLE 8.—Soybean oil equivalents from experiment 3 % Soybean oil in tallowsoybean oil blend 50 37i 25 12| 0
Soyt >ean oil equivalentXIOO Found 11% Level 93 93 89 86 84
16% Level 104 95 97 86 81
Calculated Mean
components
98 94 93 86 83
92 89 87 85
—
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4.125 2.75 1.375 0 8
Tallow
in the usual way, by comparing the M.E. values of diets containing the test fats with the M.E. value of a reference diet containing glucose, but rather by comparing the test fats with soybean oil, the digestibility and M.E. of which have already been carefully measured (Young and Artman, 1961). The metabolizable energy values were corrected for nitrogen retention. Results of the experiment are shown in Table 9. The weight and feed efficiency values for each replication are given together with their averages over the two trials. Results of the two runs differed slightly but significantly; in the second run the weights were generally higher and the feed per gain ratios lower than in the first. There were no significant interactions between replication and any other experimental factors. Variation between replications was taken into account in the analysis of variance.
Soybean oil Acidulated soybean oil soapstock Soybean oil fatty acids Menhaden oil Tallow (prime beef) Tallow fatty acids Soybean o i l + 7 i % tallow Soybean oil+111% tallow Soybean o i l + 7 J % tallow fatty acids Soybean oil soapstock+7i% tallow Soybean oil s o a p s t o c k + l l | % tallow Soybean oil soapstock+7|% tallow fatty acids Soybean oil fatty acids+7^% tallow Soybean oil fatty acids+7J% tallow fatty acids Menhaden o i l + 7 | % tallow Menhaden oil+7J% tallow fatty acids 1,450 1,506 1,471
1,442 1,535 1,419 28.9
461 518
1,439 1,504
34.9
1,537 1,495 1,464 1,099 1,532 1,480 1,548 1,530 1,523 1,543 1,524
1,520 1,432 1,455 1,080 1,545 1,417 1,504 1,556 1,522 1,504 1,502
Expt. 4A Expt. 4B
d cd d cd cd bed
b
cd be be
1
21.3
1,446 1,520 1,445
b cd b
1,450 b 1,511 bed
1,529 1,463 1,460 1,090 1,538 1,448 1,526 1,543 1,522 1,524 1,513
Mean
8 Week weight—g.
0.022
.81 .81 .89
.89 .81
.74 .85 .84 .04 .86 .98 .76 .81 .83 .81 .85
0.017
1.82 1.80 1.86
1.85 1.80
1.72 1.83 1.78 2.04 1.89 1.91 1.75 1.80 1.78 1.80 1.82
Expt. 4A Expt. 4B
0.014
1.82 1.81 1.88
1.88 1.81
be b d
b
d
1.74 a 1.85 bed 1.82 be f 2.04 1.88 d 1.95 e 1.76 a 1.81 b 1.81 b 1.81 b 1.84 bed
Mean
1
8 Week feed/Gain ratio
1.26
78.3 83.5 75.9
74.9 84.7
ef bed f
be
f
95.6 a 86.2 be 93.8 a 96.2 a 68.4 g 56.9 h 87.1 b 80.0 de 80.2 de 83.0 cd 77.9 ef
%„2
Fat digestibility
0.21
7.70 8.21 7.74
7.57 8.50
9.07 8.13 8.83 9.25 7.32 6.01 8.71 8.34 8.40 7.99 7.86
efg efg
bedef
bed
fg
bede bede defg defg
abc
g h
cdef
ab a
a
Fat metabolizable energy Cal./g. 1 ' 2
2
See footnote 1, Table 3. Soybean oil was taken as the reference for determinations of fat digestibility and metabolizable energy. The values shown for it were determined in previous work.
1
Standard Error of the Means
H% 7|%
7\% 7J%
15% 15% 15% 15% 15% 15% 7i% 3|% 7|% 7J% 3|% 7J%
Added fats
TABLE 9.—Experimental outline and results for experiment 4
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1002
N. R. ARTMAN
TABLE 10.—Diet formulation for experiment 4 Ingredient Soybean meal (50% protein) Ground yellow corn Fish meal (55% protein) Meat scrap Distillers dried solubles Dehydrated alfalfa meal Dicalcium phosphate Ground limestone Mineral and penicillin mixture 1 Vitamin mixture A2 Chromic oxide bread (50% Cr2Os) Fat
% 30.50 34.15 6.00 6.50 2.50 2.00 0.60 0.55 0.60 0.60 1.00 15.00
growth responses produced by these fats individually, and likewise that the performance of palmitic acid was improved by mixing it with oleic acid. Although pure linoleic acid was not fed, a mixture of linoleic and palmitic acids gave the same results as a mixture of oleic and palmitic acids. It appears that oleic and linoleic acids are similar in their ability to enhance the utilization of palmitic acid, at least under the conditions of this experiment in which natural ingredients in the diet supplied appreciable quantities of both oleic and linoleic acids. These results strongly support the view that relatively unsaturated fats are able to increase the utilizability of relatively saturated fats. The second experiment showed that the same effects occur whether the relatively saturated and the relatively unsaturated components are supplied both as neutral triglycerides, both as free fatty acids, or as mixtures of triglycerides and fatty acids. The third experiment confirmed that a mixture of equal parts of tallow and soybean oil is nearly equivalent to soybean oil alone in its ability to promote growth under con-
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1 This amount of mineral and penicillin mixture supplied: 500 mg. iodized salt, 31 mg. MnSCu-FtO, 69 mg. penicillin in limestone per 100 g. of diet. 2 This amount of vitamin mixture supplied: 344 mg. choline chloride (25% concentrate), 0.33 mg. riboflavin, 1.10 mg. calcium pantothenate, 3.3 mg. niacin, 65.6 mg. B12 concentrate (6 mg./lb.), 49.9 mg. methionine, 110 mg. vitamin A (10,000 I.U./g.), 0.55 mg. vitamin D 3 (250,000 I.C.U./g.), and 25 mg. ground corn per 100 g. of diet.
ditions of equalized feed intake, but that further dilutions of the soybean oil with tallow result in diminutions of the growthpromoting power of the mixture. When the mixture contained only 12^>% soybean oil, the difference between its growth-promoting ability and the growth-promoting ability calculated for it on the basis of its components was too small to measure; that is, the utilizability of the tallow component was not increased enough to be measured in an experiment of this size. When the mixture contained 25% soybean oil, however, there was enhancement of its energy value, and the utilizability of the tallow component appears to have been increased. From a plot of soybean oil equivalents versus percent soybean oil in the soybean oil-tallow mixtures, it can be seen that the mixtures are better utilized than is tallow alone. Within the area of uncertainty attendant upon the experimental error the extent of enhancement is proportional to the soybean oil content, over the range of 0 to 50% soybean oil. Thus, the addition of a given percentage of soybean oil to tallow apparently leads, not only to the expected high utilization of the soybean oil itself, but to equally good utilization of a portion of the tallow equal in weight to the weight of the soybean oil added. In general the results of the fourth experiment, which employed ad libitum feeding, confirmed the results of the three restricted feeding experiments. Mixtures of soybean oil, acidulated soapstock from soybean oil refining, or soybean oil fatty acids with tallow or tallow fatty acids gave results better than the averages calculated for these mixtures of animal and vegetable stocks, as measured by feed efficiency, absorbability, or metabolizable energy. This was true for all of the mixtures tested, as a group, and for most of the individual mixtures. The extent to which the metabolizable
1003
INTERACTIONS OF FATS AND FATTY ACIDS TABLE 11.—Comparison of experimental findings Restricted feeding results Expt. 1
Expt. 2
Expt. 3
SBO SBO fatty acid Tallow Tallow fatty acid SBO+tallow (1:1) SBO+tallow (1:3) SBO+tallow fatty acids (1:1) SBO fatty acids +tallow(l: 1) SBO fatty acids+tallow fatty acids (1:1)
100
100 106 76 57 100
100
79 96
ME ratio
Digestibility ratio
93 103
100 96 80 65 95 91 92 93
100 98 72 58 91 84 84 89
100 96 93 89 99 96 96 96
99
84
82
96
energy values of the tallow and tallow fatty acids were enhanced by admixture with intact or hydrolyzed soybean oil appeared to be approximately proportional to the level of the soybean oil stocks in the mixtures. The various fats tested gave widely ranging values for feed efficiency, digestibility, and metabolizable energy; nevertheless, for any given fat all three of these values corresponded closely with each other, and all appeared to be valid measurements of the nutritive value of different kinds of fat. Insofar as comparisons can be made, both the restricted feeding experiments and the ad libitum feeding test gave similar results. Table 11 shows this comparison in detail. The first three columns are averages of soybean oil equivalents found in Experiments 1-3. The next three columns are results from Experiment 4 expressed as ratios of metabolizable energy, digestibility, and feed efficiency (gain/ feed) of the test fats to the corresponding values for soybean oil. All values in the table have been multiplied by 100 for easier reading. In general the various sets of values are in good agreement. The feed efficiency values cover a much shorter range than the other values. This is to be expected since they represent the feed efficiencies of the entire rations, whereas the other values rep-
83 98 93
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resent the values of only the variable portion of the rations, that is, the fats. It is interesting that the soybean oil equivalents, which are based on chick growth, tend, in general, to be somewhat higher than the values based merely on the disappearance of fat and energy from feed material as it passes through the digestive tract. This discrepancy may be related to special extra-caloric growth-promoting properties of fats and oils which have been postulated by some workers (Dam et al, 1959); the restricted feeding results would seem to be more closely related to productive energy than are the digestibility and M.E. values, and to be more meaningful measurements of the property which has the greatest economic significance for the poultry producer, namely the cost of producing a pound of marketable meat. The results for menhaden oil are unique and anomolous, both in Experiment 2 and in Experiment 4. As would be expected for so unsaturated a fat, it has high digestibility and M.E. values. When fed at levels of 4J/2% to 9% of the diet, it promoted good growth and feed efficiency, quite in keeping with its high digestibility. At a level of 12 % (Experiment 1) it led to poorer growth than would have been expected, showing a soybean oil equivalent of only .86, rather than .96 as it did at the 9% level. At the
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Fat
Ad libitmn feeding results expt. 4
1004
N. R. ARTMAN
SUMMARY
Mixtures of fats and fatty acids having different degrees of unsaturation were evaluated and compared as energy sources for the chick in three controlled or restricted feeding tests, in which growth was proportional to the energy value of the fat, and one conventional eight-week test, in which growth, feed efficiency, digestibility, and metabolizable energy were measured. The following conclusions were reached: 1. The utilizability of relatively saturated fats or fatty acids is increased by mixing them with relatively unsaturated fats or fatty acids. 2. Successive increments of relatively unsaturated fat, added to a relatively saturated fat, effect successively smaller increases in the utilizability of the relatively saturated fat. 3. Although menhaden fish oil is well utilized, and mixtures of it with other fat produce good growth and feed efficiency, at high levels it tends to suppress chick growth. 4. The controlled feeding technique gives results in substantial agreement with more conventional measurements
of fat utilizability. The controlled feeding technique has the advantage of quickly comparing different fats under conditions which essentially evaluate their productive energy values. REFERENCES Dangoumau, A., and H Debruyne, 1963. Utilisation des huiles obtenues par esterification des acides gras distilles pour l'enrichissement des rations pour poulets de chair. Revue Francaise des Corps Gras, 10: 259-271. Dansky, L. M., 1961. The growth promoting properties of menhaden fish oil as influenced by various fats. Poultry Sci. 41: 1352-1354. Dam, R., R. M. Leach, Jr., T. S. Nelson, L. C. Norris and F. W. Hill, 1959. Studies on the effect of quantity and type of fat on chick growth. J. Nutrition, 68: 615-632. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Mattson, F. H., 1960. An investigation of the essential fatty acid activity of some geometrical isomers of unsaturated fatty acids. J. Nutrition, 71: 366-370. Pepper, W. F., S. J. Slinger and I. R. Sibbald, 1962. A comparison of feed grade tallow and a mixture of tallow and acidulated soapstocks in practical chicken roaster rations. Poultry Sci. 41: 11631168. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1960. A synergistic relationship between tallow and undegummed soybean oil. Poultry Sci. 39: 1295. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1961. Factors affecting the metabolizable energy of content of poultry feeds. 2. Variability in the M.E. values attributed to samples of tallow and undegummed soybean oil. Poultry Sci. 40: SOSSOS. Sibbald, I. R., S. J. Slinger and G. C. Ashton, 1962. The utilization of a number of fats, fatty materials and mixtures thereof evaluated in terms of metabolizable energy, chick weight gains and gain: feed ratios. Poultry Sci. 41: 46-61. Young, R. J., 1961. The energy value of fats and fatty acids for chicks. 1. Metabolizable energy. Poultry Sci. 41: 1225-1233. Young, R. J., and N. R. Artman, 1961. The energy value of fats and fatty acids for chicks. 2. Evaluated by controlled feed intake. Poultry Sci. 40: 1653-1662. Young, R. J. and R. L. Garrett, 1963. The effect of oleic and linoleic acids on the absorption of saturated fatty acids in the chick. J. Nutrition, 81: 321-329.
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15% level (Experiment 4) it gave very much poorer growth and feed efficiency than any other of the fats tested. Mixtures of fish oil with tallow or tallow fatty acids were nearly as good, by the criteria examined, as mixtures of soybean oil with tallow or tallow fatty acids, but there was no suggestion that fish oil increased the metabolizable energy or digestibility of tallow or tallow fatty acids. All in all, it appears that the fish oil contains a factor or quality, or perhaps a deficiency, which causes it to interfere with the proper utilization of absorbed energy by the chick, when it is fed at levels as high as 12 to 15%. That this interfering factor is related to the oxidative instability of the oil is a reasonable assumption but, at present, no more than that.