- Email: [email protected]
Factors Affecting the Absorbability of Fatty Acid Mixtures High in Saturated Fatty Acids1
Factors Affecting the Absorbability of Fatty Acid Mixtures High in Saturated Fatty Acids1 R. J. Y O U N G , R. L. GARRETT AND M. G R I F F I T H Department of Poultry Husbandry and Graduate School of Nutrition, Cornell University, Ithaca, New York (Received for publication March 11, 1963)
T
A detailed examination of the conditions under which these experiments were conducted showed a number of differences in the experimental diets and environmental conditions. The basal diet described by Young (1961) was made u p en1 This investigation was supported in part by Public Health Service Research Grant AM04569 from the National Institute of Arthritis and Metabolic Diseases, and by a grant-in-aid from The Procter and Gamble Co., Cincinnati, Ohio.
tirely of practical feedstuffs and provided 2 8 % protein, with ground yellow corn as the principal source of carbohydrate. On the other hand, the experimental diet E-16 used by Renner and Hill (1961) was a semi-purified diet containing approximately 2 4 % protein with glucose as the only source of carbohydrate (Hill et al., 1960). In addition, Young (1961) used Arbor Acre White Plymouth Rock cockerels which were fed the basal diet containing no added fat for the first week. The chicks were then fed the experimental diets containing the test fats substituted for 1 5 % glucose on a weight for weight basis for three weeks. Renner and Hill (1961) on the other hand used crossbred cockerel chicks ( R I R X B P R ) 2 which were reared for two weeks on the basal diet. These chicks were then fed the experimental diets which contained 1 7 % fat substituted isocalorically for glucose, for a period of two weeks. Further comparison showed t h a t a significant difference existed in the environmental conditions of the two laboratories. The experiments reported by Young (1961) were conducted in a laboratory which was cleaned and fumigated between each experiment, and at any one time contained only chicks of the same age. On the other hand, the laboratory used by Renner and Hill (1961) housed a variable number of experiments a t all times with chicks ranging in age from one to four
1146
2
Rhode Island RedXBarred Plymouth Rock.
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
H E absorbability values in chicks of a number of natural triglycerides and their hydrolyzed fatty acid mixtures were determined by Young (1961) and by Renner and Hill (1961). I n both studies the percentage absorbability of the total mixture and of the individual fatty acids contained in these mixtures was determined. Very good agreement was obtained on the absorbability of the total lipid and the fatty acids contained in these lipid materials for soybean oil, soybean oil fatty acids, lard and tallow. However, the absorbability values found for beef tallow fatty acids and lard fatty acids by these two investigators were markedly different. The absorbability values reported by Young (1961) for both tallow fatty acids and lard fatty acids were considerably higher than values found b y Renner and Hill (1961). Examination of the absorbability values of the individual fatty acids in each of the fatty acid mixtures shows t h a t most of the discrepancy occurred in the absorbability of palmitic and stearic acids.
1147
ABSORBABILITY OF FATTY ACIDS
weeks or older. Although the batteries were thoroughly cleaned between experiments, the laboratory as a whole was not fumigated between experiments. Because of these differences in environment and experimental techniques, a series of experiments was conducted to determine if any of these variables affect the absorbability of fatty acid mixtures derived from hydrolyzed lard or beef tallow. EXPERIMENTAL PROCEDURE AND RESULTS
The fatty acid mixtures were analyzed for their fatty acid composition by subjecting the methyl esters of the fatty acids to gas liquid partition chromatography at 190°C. using a 2 meter X0.25 inch diameter column containing succinate polyester of diethylene-glycol as the liquid phase, 3 Alcoholic KOH contained one gram of KOH for each 5 ml. of 50% ethanol.
Ingredients
Experiment 1 A
% •—
Corn, ground 27.8 Glucose 1 Soybean meal (50% protein) 35.0 Isolated soybean protein 8 1.0 Fish meal 5.0 2.5 Whey, dried Corn distillers solubles 2.5 2.0 Alfalfa meal, dehydrated DL-Methionine 0.4 Glycine Cellulose 2.2 Dicalcium phosphate Limestone 1.0 Mineral mix#l 3 2.0 Vitamin mix #1 4 1.1 CrjOs bread' 1.0 Glucose and/or fatty acid mixture 16.5
— —
Experiment 2 B
%
14.9 10.0 7.0 25.0 5.0 2.0 2.5 2.0 0.3
—
4.0 2.2 1.0 1.1 1.1 1.0 20.0
C
% 32.0
— • — — . — — 0.7
35.47
0.3 3.0 3.28 1.25 2.0 1.1 1.0 20.0
1 Cerelose, Corn Products Company, New York. * C-l Assay Protein, Archer-Daniels-Midland, Minneapolis. * Mineral mix #1 supplies, per 100 gm. diet: gm.: NaCI, 0.8; KC1, 0.5; MgSO., 0.25; KHsPCU, 0.2; CaCOa, 0.1807; mg.: MnSCvEM), 30.0: FeS04-7HsO, 30.0; CuSO<-5H20, 3.0; ZnO, 6.0; Nal, 0.209; NasSeOs, 0.022; NaMo04-2HiO, 0.1. * Vitamin mix #1 supplies, per 100 gm. diet: vitamin A (stabilized), 1,000 IU; vitamin Dj, 150 ICU; vitamin E, 11.0 IU;_ mg.: choline CI, 200; niacin, 4.0; Ca pantothenate, 2.0; thiamine-HCl, 1.0; riboflavin, 1.0; pyridoxine-HCl, 1.0; menadione, 0.25; folic acid, 0.2; biotin, 0.03; vitamin Bn, 0.005; glucose (40 mesh screen) to provide 1.1 gm. of mix per 100 gm. of diet. 5 CnOa bread—30% CreOs in wheat flour, mixed with water to a thin dough, dried at 70°C. and ground to a fine powder.
and a thermister detector. Helium was used as the carrier gas at a flow rate of 80 mm. per minute. Except when otherwise noted, all chicks in each experiment were fed a lowfat basal diet similar to diet B, Table 1, for a period of one week. At this time they were allotted on the basis of body weight to the experimental groups. In all but the first experiment duplicate groups of 8 chicks each were fed each of the experimental diets for three weeks. Feed and water were supplied ad libitum over the four week experimental period. White Plymouth Rock chicks from a commercial hatchery were used in all but the first experiment; in this experiment R I R X B P R crossbred chicks were compared to the White Plymouth Rock chicks. The chicks were housed in electricallyheated, thermostatically-controlled battery brooders with raised wire screen floors. Excreta collections were made at
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
A series of four experiments was conducted. The fatty acids used in these experiments were prepared by hydrolysis of either lard or beef tallow. Approximately 18 kg. of fat were hydrolyzed at one time, using 150 ml. of alcoholic KOH 3 for every 100 gm. of fat. The solution was refluxed 5 hours in a steam kettle under a large condenser. After hydrolysis the mixture was cooled and slowly acidulated with diluted sulfuric acid. The free fatty acids were allowed to separate from the acid-water seat, the latter was removed and the fatty acids were washed 5 times with water. After complete separation of the final water wash, which was discarded, 0.0125% ethoxyquin was added to the fatty acid mixture which was stored in cans under nitrogen at 0°C. until used. Each preparation of fatty acid was titrated with standard sodium hydroxide solution to demonstrate complete hydrolysis.
TABLE 1.—Experimental basal diets
1148
R. J. YOUNG, R. L. GARRETT AND M. GRIFFITH TABLE 2.—Experimental basal diets Experiment 3 Ingredients
28% Protein D
E
%
%
Experiment 4
24% Protein
30% Protein
24% Protein
K
%
%
Ground corn 33.0 25.2 Glucose1 47.4 38.9 17.7 16.2 42.0 Protein premix A2 51.3 51.3 42.0 3 Protein premix B Isolated soybean protein' 2.5 3.3 Dicalcium phosphate 2.2) Limestone 1.0 Mineral mix #1 6 2.0 •Constant ingredients in all diets 6 Vitamin mix #1 1.1 1.0 Cr20;, bread7
M
%
%
%
%
18.7 20.0 54.0
— 36.85 54.0 1.85
32.3 20.0 40.4
— 49.11 40.4 3.19
Cerelose, Corn Products Company, New York. Protein premix A contains in gms./lOO gms.: soybean meal (50% protein), 68.23; isolated soybean protein4, 8.77; fish meal (60% protein) 9.75; corn distillers solubles, 4.87; dried whey, 3.90; dehydrated alfalfa meal, 3.90; DL-methionine, 0.58. This premix contains 50.8% protein and 1,192 metabohzable energy Calories per pound. 3 Protein premix B, similar to premix A above but contains 11.47% isolated soybean protein and therefore contains 52.6% protein and 1,190 metabohzable energy Calories per pound. 4 C —1 Assay Protein, Archer-Danie's-Midland, Minneapolis. 6 See footnote 3, Table 1. 6 See footnote 4, Table 1. 7 See footnote 5, Table 1.
four 24-hour periods between the 24th and 28th day. Immediately after collection the excreta were frozen. At the end of four days the excreta samples were combined, homogenized in a Waring blendor and dried at 70°C. in a forced air oven. Analyses were made on both the diet and the dried excreta for moisture, total lipids and chromium. Chromic oxide was incorporated in each diet as an index substance, thus eliminating the need for quantitative collection of excreta. The methods for processing excreta, conducting chemical determinations for chromium, fat and moisture, and computing fat absorbability from these data have been described by Hill et al. (1960), Renner and Hill (1960) and Young (1961). The method used for the determination of fecal fats measures all lipid fractions including triglycerides, free fatty acids and any fatty acids present in the form of soaps.
In each experiment chicks were fed diets containing the test fatty acid and other groups of chicks received a similar diet containing an equivalent amount of glucose in place of the fatty acid. The latter treatments were included for purposes of determining endogenous fat excretion and absorbability of the fat in the constant ingredients for each experimental diet. Fumigation of the animal laboratory and equipment was carried out immediately after cleaning by reacting 320 grams of potassium permanganate with 590 grams of formaldehyde for every 1,000 cu. ft. of laboratory space. The humidity in the room was increased by the simultaneous use of steam. Experiment 1. This experiment was designed to determine if there was a difference in fatty acid absorbability between White Plymouth Rock and R I R X B P R chicks. In this.experiment triplicate lots of
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
1
2
1149
ABSORBABILITY OF FATTY ACIDS
Experiment 2. Chicks in this experiment were fed either the practical or the purified basal diets B and C, respectively (Table 1), in which 20% lard fatty acids were subT A B L E 3.—Absorption of hydrolyzed animal by two different breeds of chicks (Experiment 1)
fats
Average weight, 4 weeks
rF e( .e,QJ / Il Iu , / gam
15% Lard fatty acids White Plymouth Rocks RIRXBPR'
644 434
1.38 1.42
87 87
89 87
15% Tallow fatty acids White Plymouth Rocks RIRXBPR
589 434
1.53 1.55
66 70
68 72
Treatment
1
Fat absorption 2 weeks 4 weeks
%
Rhode Island Red and Barred Plymouth Rock crossbreed.
T A B L E 4.—Absorption of lard fatty acids when fed for either two weeks or three weeks prior to fecal collection (Experiment 2) Number
Absorption
Treatment
™**™ t a t t y acids
Basal Basal <
L a r d f a t t y acids, 2 0 % L a r d f a t t y acids, 2 0 %
2 3
1
% 73 76
% 76 81
Basal diets shown in T a b l e 1.
stituted for glucose on a weight for weight basis. The chicks were fed the low fat basal diets containing glucose for either one or two weeks, followed by a three and two week feeding period, respectively, in which the diets contained the lard fatty acids. Chicks fed the diet containing the lard fatty acids for three weeks showed a significantly greater absorbability of the fatty acids than chicks fed the same diet for a two week period (Table 4). These results also showed that the absorbability of lard fatty acids when fed for either 2 or 3 weeks was higher in those chicks fed the basal diet made up of the practical ingredients (Diet B, Table 1) as compared to those fed purified diet C. Experiment 3. The third experiment was designed to compare the major differences in the experimental diets used by Young (1961) as compared to Renner and Hill (1961). The differences compared were the amount of protein, the use of corn vs. glucose as the major source of carbohydrate, and the isocaloric substitution of the fatty acids for glucose as compared to a weight for weight substitution for glucose in the test diets. The 28% protein diet (Diet A, Table 1) containing 16.5% glucose, was fed to all chicks for the first week. At this time they were allotted on a weight basis to the experimental groups. Duplicate lots of chicks were fed either a 24% or a 28% pro-
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
each breed with 15 chicks per lot were fed experimental basal diet A (Table 1) supplemented with hydrolyzed lard or beef tallow (15%) in place of glucose on a dry weight basis. The chicks were fed the diets containing the fatty acids from one day of age, and fecal collections were made at both the 2 and 4 week periods of the experiment. This experiment was conducted in a laboratory which had just been fumigated. The results are summarized in Table 3. They show that there is no difference between the two strains of chicks in their ability to utilize lard fatty acids or beef tallow fatty acids. Both strains showed a slightly greater absorbability of the tallow fatty acids at 4 weeks of age as compared to the absorbability measured at 2 weeks of age. However, the difference between the two age groups was not as great as that observed by Renner and Hill (1960) for tallow. No differences were observed in the absorbability at 2 and 4 weeks with chicks fed the lard fatty acids. The absorbability values found in this experiment compared favorably with those reported by Young (1961) for both the lard and beef tallow fatty acids.
1150
R. J. YOUNG, R. L. GARRETT AND M.
tein diet with either ground corn or glucose as the primary source of carbohydrate (Diets D , E, F, G, Table 2). Each diet was fed with and without lard fatty acids substituted weight for weight for glucose on a dry weight basis. I n addition, lard fatty acids were substituted isocalorically for glucose at both protein levels. Chicks were fed the experimental diets from 7 to 28 days of age, and excreta collections were made during the fourth week of the experiment. This experiment was conducted in an animal laboratory which had just been cleaned and fumigated.
( P < 0 . 0 5 ) when fed in the 2 8 % protein diets as compared to the 2 4 % protein, regardless of the type of carbohydrate. Within each protein level the use of corn as a source of carbohydrate in place of glucose significantly ( P < 0 . 0 1 ) improved the absorbability of the lard f a t t y acids. This was in contrast to the isocaloric substitution of the lard fatty acids for glucose which gave a lower absorbability value for these fatty acids at both levels of dietary protein. I t appears t h a t the absorbability value for beef tallow fatty acids must be influenced in a similar manner. The absorbability value for beef tallow fatty acids was significantly higher when these fatty acids were fed in the 2 8 % protein diet with corn as the carbohydrate, as compared to t h a t obtained in the 2 4 % protein diet with glucose as the carbohydrate. T h e significant decrease in absorbability of the lard fatty acids substituted isocalorically for glucose in the 2 4 % protein diet appears to be in conflict with the observation t h a t increasing the protein level of the diet increases the absorption of lard fatty acids. On the other hand, it is possible t h a t markedly reducing the amounts
TABLE 5.—Effect of level of protein and source of carbohydrate on the utilization of animal fatty acids (Experiment 3) Treatment
M.E. Calorie ."protein ratio1
Weight, 4 weeks
Feed/lb. gain
Absorbability
%
gms.
28% Protein diet 1. 15% Lard fatty acids+glucose 2. 15% Lard fatty acids+corn 3. 15% Lard fatty acids (isocaloric) 4. 15% Tallow fatty acids+corn
51 53 43 51
644 638 618 633
1.64 1.55 1.82 1.61
74"2 82 d 72»b 74a
24% Protein diet 5. 15% Lard fatty acids+glucose 6. 15% Lard fatty acids+corn 7. 15% Lard fatty acids (isocaloric) 8. 15% Tallow fatty acids+glucose
63 63 54 61
650 640 624 654
1.69 1.63 1.66 1.67
71 b 78" d 64 ° 66 b °
1 1
Calories of metabolizable energy per pound of diet divided by the percentage protein in the diet. Absorbability values with the same letter superscript are not significantly different. (Duncan, 1955)
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
The effects of the various treatments are summarized in Table 5. Excellent growth and feed conversion were obtained. I n making comparisons of the feed conversion values it should be noted t h a t there were significant changes in the energy: protein ratios due to the changes in protein levels and the methods of substitution of fat. These d a t a show t h a t level of protein, type of carbohydrate and method of substitution of the lard fatty acids all significantly influenced the absorbability of lard fatty acids. The absorbability of the lard fatty acids was significantly higher
GRIFFITH
1151
ABSORBABILITY OF FATTY ACIDS
and which also contained chicks of various ages. However, this was a relatively new laboratory and was not the same building which housed Experiments 1, 2 and 3. Chicks were fed diet A (Table 2) for the first week, whereupon they were allotted to experimental groups on an equal weight basis. Duplicate groups of 8 chicks in both the fumigated and non-fumigated laboratories were fed the various experimental diets containing the lard fatty acid both with and without a mixture of three antibiotics (Table 6). I n addition duplicate lots of 3 chicks each in both the fumigated and non-fumigated laboratories were fed each of the basal low-fat diets (J, K, L and M, Table 2) with and without antibiotics for a total of 16 low fat control diets. Correction for endogenous fat and fecal fat contributed by the constant diet ingredients was made from data obtained from the appropriate control treatment. There were no significant differences in
TABLE 6.-—Effect
of environment and dietary changes on the absorption of lard fatty acids by the chick (Experiment 4) Plus antibiotic I
No antibiotic Ave. wt., 4 wks. 30% Protein basal Non-fumigated laboratory 20% Lard fatty acids+glucose 20% Lard fatty acids+corn
Feed/lb. gain
gms.
Absorbability
Ave. wt.., 4 wks.
%
gms.
Feed/lb. gain
Absorbability
%
625 668
1.62 1.52
732 73
713 677
1.45 1.44
75' 73
Fumigated laboratory 20% Lard fatty acids+glucose 20% Lard fatty acids+corn
694 668
1.50 1.48
77 74
712 691
1.45 1.47
81 81
24% Protein basal Non-fumigated laboratory 20% Lard fatty acids+glucose 20% Lard fatty acids+corn
670 652
1.56 1.57
69 72
703 668
1.48 1.46
72 72
Fumigated laboratory 20% Lard fatty acids+glucose 20% Lard fatty acids+corn
679 665
1.60 1.56
69 73
697 700
1.52 1.43
78 75
1
50 p.p.m. each of penicillin, zinc bacitracin, chlortetracycline. Analyses of variance of this experiment taking into account the factorial arrangements of the treatments showed a highly significant (P<0.01) effect from the fumigated vs. the non-fumigated laboratory, from the 30% protein vs. the 24% protein diet and from the use of the antibiotics. The Laboratory times Antibiotic interaction was the only one out of 11 interactions which was significant (P<0.05). 2
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
of carbohydrate in the diet, by the isocaloric substitution technic may reduce the absorption of the lard fatty acids. Experiment 4. The fourth experiment in this series was conducted to determine the effect of fumigation of the chick laboratory and the effect of dietary antibiotics on the absorption of lard fatty acids. I n this experiment chicks were fed the basal diets J, K, L and M (Table 2) in which the 2 0 % lard fatty acids were substituted for glucose on a weight for weight basis. The protein level of the high protein diet was increased to 3 0 % protein in an a t t e m p t to accentuate the difference due to protein level. In addition the lard fatty acids were substituted for glucose at 2 0 % of the diet instead of 1 5 % in order to have a greater percentage of the calories in the diet supplied by the fatty acids. The complete experiment was duplicated in a fumigated laboratory and in a laboratory in which chicks had been housed previously
1152
R. J. Y O U N G , R. L. G A R R E T T AND M.
growth or feed conversion of chicks fed the various low fat diets except for a small growth response of chicks fed the diets containing the antibiotics. The average 4 week weight and feed conversion of 8 treatments without antibiotics was 665 gm. with 1.77 gm. of feed per gm. of gain as compared to an average of 685 gm. with 1.74 for the average feed conversion for the 8 treatments receiving the antibiotics.
The results of feeding lard fatty acids under these various conditions are summarized in Table 6. A highly significant ( P < 0 . 0 1 ) increase in absorbability of the lard fatty acids occurred under the following conditions: (1) when the chicks were housed in the fumigated laboratory as compared to those in the non-fumigated laboratory; (2) when the lard fatty acids were fed in a high protein diet versus a low protein diet; (3) when antibiotics were included in the diet versus no antibiotic added to the diet. I t should be noted t h a t a laboratory-time-antibiotictreatment interaction was observed which was significant a t the P < 0 . 0 5 level of probability showing t h a t the improvement in the absorbability of the lard fatty acids due to the addition of antibiotics was greatest in those chicks housed in the fumigated laboratory. In this experiment there was no effect of the type of carbohydrate on the absorbability of the lard
fatty acids. This was in contrast to the results observed in experiment 3, where the use of corn in place of glucose significantly improved the utilization of lard fatty acids. At present there is no explanation for this observed difference in the two experiments. DISCUSSION The results of these experiments show t h a t the absorbability of lard and beef tallow fatty acids can be significantly affected b y dietary and environmental conditions. The most significant of these factors is the level of protein in the diet. In every case there was an improvement in absorbability of both the beef tallow and the lard fatty acids when the level of protein in the diet was increased from 24 to 2 8 % or 24 to 3 0 % . Similar observations have been made in the rat. Barnes et al. (1944) fed triglycerides to rats and observed a higher fat digestibility in diets containing 3 0 % protein as compared to those containing 1 4 % protein. Carroll and Richards (1958) observed t h a t the digestibility of erucic acid by the r a t was improved as the protein level in the diet was increased. I n one experiment a significant improvement in absorbability occurred when corn was used as the principal source of carbohydrate as compared to glucose. However, this effect of carbohydrate was not observed in the fourth experiment, and therefore cannot be considered as a consistent variable. Intestinal a n d / o r environmental microflora apparently have a significant effect on the absorbability of these animal fatty acids, since the absorbability is always higher in those chicks which are reared in a laboratory which has just been recently fumigated as contrasted to chicks reared in a laboratory which has housed a number of experiments and contains
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
The endogenous fat excretion was not influenced b y antibiotics, environment or level of protein. However, the chicks fed all diets containing corn excreted more fecal fat (2.27% of excreta) than those fed diets containing glucose (1.45% of the excreta). This difference was expected and was of the same magnitude as t h a t observed in the other experiments. I t was due in p a r t to the fact that the low fat corn diet contained 2.38% fat while the low fat glucose diets contained 1.16% fat.
GRIFFITH
ABSORBABILITY OF FATTY ACIDS
The results of these experiments show that the absorbability of hydrolyzed lard and beef tallow can be influenced by a number of environmental and dietary conditions. Apparently many or some of these effects are additive. Therefore the difference in absorbability of these two sources of fatty acids observed by Renner and Hill (1961) and Young (1961) under the two different experimental conditions which were described can probably be attributed to a number of individual factors. These factors appear to be sufficiently additive to cause a marked differ-
ence in the absorbability values of lard and beef tallow fatty acid mixtures. SUMMARY
A series of experiments was conducted with chicks to determine environmental and dietary conditions which affect the absorbability of lard and beef tallow fatty acids. The absorbability of lard fatty acids was found to be increased when fed in a 28% or 30% protein diet as compared to a 24% protein diet, and when fed for a three week period prior to fecal collection, rather than for a two week period. Absorbability was higher when the fatty acids were substituted for glucose on a weight for weight basis rather than isocaloric substitution. The use of corn as a major source of carbohydrate rather than glucose improved absorption in one experiment, but this variable did not appear to have a consistent effect. There was no difference in absorption of these fatty acids in two breeds of chicks tested. The rearing of chicks in a fumigated laboratory significantly improved the absorbability of lard fatty acids, particularly if the fatty acids were fed in a high protein diet. The combination of three antibiotics in the diet improved the absorbability of lard fatty acid particularly if the chicks were reared in a fumigated laboratory. These factors appear to be sufficiently additive to cause a marked difference in the absorbabilities of lard fatty acid or beef tallow fatty acids in the chick, depending on the specific conditions of the experiment. REFERENCES Afifi, M., 1959. Uber den Einfluss antibiotischer Wirkstoffe in verschiedenen Dosierrungen auf Kiikenwachstum und Futterverdaulichkeit. Arch. of Kleintierzucht, 23: 404-408. Barnes, R. H., M. F. Primrose and G. O. Burr, 1944. The influence of the protein content of the diet upon fat digestibility. J. Nutrition, 27: 179-184.
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
chicks of various ages. Donaldson (1962) observed the greatest growth response to 10% added animal fat occurring in chicks reared in new electrically heated batteries as contrasted with chicks reared in old batteries. However, it is not known if the improved growth observed by Donaldson was due to an improvement in the absorbability of the dietary fat. The relationship of intestinal microflora to lard fatty acid absorption is also evident by the response to antibiotic. It was of interest to see that the greatest response to antibiotic occurred in those chicks housed in a fumigated laboratory. It would appear that the microflora which existed in the laboratory which had just been fumigated was more susceptible to antibiotic control than the microflora which develop over a period of time in the non-fumigated laboratory. Afifi (1959) observed an improvement in growth, feed utilization and digestibility of fat in 4 week old chicks fed either 25 p.p.m. aureomycin or 40 p.p.m. penicillin. Terramycin was without effect. Supplee (1960) observed that turkey poults showed a 20% increase in growth due to the addition of 13% corn oil to the diet in the presence of 50 p.p.m. of oleandomycin and only a 10% increase in the absence of the antibiotic.
1153
1154
R. J. YOUNG, R. L. GARRETT AND M. GRIFFITH
Carroll, K. K., and J. F. Richards, 1958. Factors affecting digestibility of fatty acids in the rat. J. Nutrition, 64: 411-424. Donaldson, W. E., 1962. The response of chicks to dietary animal fat in new and old environments. Poultry Sci. 41: 1106-1108. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Hill, F. W., D. L. Anderson, R. Renner and L. B. Carew, Jr., 1960. Studies of the metabolizable energy of grain products for chickens. Poultry Sci. 39:573-579.
Renner, R., and F. W. Hill, 1960. The utilization of corn oil, lard and tallow by chickens of various ages. Poultry Sci. 39: 849-854. Renner, R., and F. W. Hill, 1961. Factors affecting the absorbability of saturated fatty acids in the chick. J. Nutrition, 74: 254-258. Supplee, W. C , 1960. The effect of antibiotic supplementation on the response of poults to dietary corn oil. Poultry Sci. 39: 227-229. Young, R. J., 1961. The energy value of fats and fatty acids for chicks. 1. Metabolizable energy. Poultry Sci. 40:1225-1233.
E. J. WLADYKA, L. E. DAWSON AND R. W. WALKER Departments of Food Science and Microbiology 6* Public Health, Michigan State University, East Lansing, Mich. (Received for publication March 13, 1963)
A
PROBLEM of major concern in the marketing of shell eggs is the heavyfinancial loss suffered annually by producers, processors and consumers due to soiled eggs. An economically effective means of removing the soil from dirty eggs would not only present a visibly cleaner product, but should also reduce the incidence of bacterial spoilage. In general, eggs cleaned by existing commercial procedures have not been as satisfactory in marketing channels as naturally clean eggs. For this reason, new or improved techniques should be investigated. According to Stuart and McNally (1943), shell eggs are generally sterile when laid, thus microbial spoilage of eggs encountered in commercial distribution channels is mainly due to the invasion of the egg by spoilage-producing organisms after the egg has been laid. Fromm and Munroe (1960) reported that interior quality and rate of bacterial contamina1 Michigan Agricultural Journal Article No. 3130.
Experiment
Station
tion are related to the permeability of the egg shell. Stuart and McNally (1943) indicated that the shell membrane may be more important as an agent in preventing contamination of the interior of the egg than the mucoid or "bloom" covering the shell. Walden et al. (1956) reported tracer experiments in which the egg shell membrane restrained the passage of microorganisms for periods of time up to 20 hours. High frequency sound waves transmitted throughout a cleaning fluid cause cavitation in the liquid. The cavitation, as reported by Johnson (1929) consists of the formation of thousands of microscopic bubbles within a liquid cleaning medium. The formation and collapse of these cavitations produce a powerful scrubbing action on soil (Carlin, 1949). Crawford (1955) reported that water was an excellent medium for ultrasonic cleaning. Murdock (1956) suggested that frequencies just above human audibility (20 Kc./sec.) were the most effective for cleaning. For a given power input, cavita-
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
The Influence of Ultrasonic Treatment on Egg Quality1
T
A detailed examination of the conditions under which these experiments were conducted showed a number of differences in the experimental diets and environmental conditions. The basal diet described by Young (1961) was made u p en1 This investigation was supported in part by Public Health Service Research Grant AM04569 from the National Institute of Arthritis and Metabolic Diseases, and by a grant-in-aid from The Procter and Gamble Co., Cincinnati, Ohio.
tirely of practical feedstuffs and provided 2 8 % protein, with ground yellow corn as the principal source of carbohydrate. On the other hand, the experimental diet E-16 used by Renner and Hill (1961) was a semi-purified diet containing approximately 2 4 % protein with glucose as the only source of carbohydrate (Hill et al., 1960). In addition, Young (1961) used Arbor Acre White Plymouth Rock cockerels which were fed the basal diet containing no added fat for the first week. The chicks were then fed the experimental diets containing the test fats substituted for 1 5 % glucose on a weight for weight basis for three weeks. Renner and Hill (1961) on the other hand used crossbred cockerel chicks ( R I R X B P R ) 2 which were reared for two weeks on the basal diet. These chicks were then fed the experimental diets which contained 1 7 % fat substituted isocalorically for glucose, for a period of two weeks. Further comparison showed t h a t a significant difference existed in the environmental conditions of the two laboratories. The experiments reported by Young (1961) were conducted in a laboratory which was cleaned and fumigated between each experiment, and at any one time contained only chicks of the same age. On the other hand, the laboratory used by Renner and Hill (1961) housed a variable number of experiments a t all times with chicks ranging in age from one to four
1146
2
Rhode Island RedXBarred Plymouth Rock.
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
H E absorbability values in chicks of a number of natural triglycerides and their hydrolyzed fatty acid mixtures were determined by Young (1961) and by Renner and Hill (1961). I n both studies the percentage absorbability of the total mixture and of the individual fatty acids contained in these mixtures was determined. Very good agreement was obtained on the absorbability of the total lipid and the fatty acids contained in these lipid materials for soybean oil, soybean oil fatty acids, lard and tallow. However, the absorbability values found for beef tallow fatty acids and lard fatty acids by these two investigators were markedly different. The absorbability values reported by Young (1961) for both tallow fatty acids and lard fatty acids were considerably higher than values found b y Renner and Hill (1961). Examination of the absorbability values of the individual fatty acids in each of the fatty acid mixtures shows t h a t most of the discrepancy occurred in the absorbability of palmitic and stearic acids.
1147
ABSORBABILITY OF FATTY ACIDS
weeks or older. Although the batteries were thoroughly cleaned between experiments, the laboratory as a whole was not fumigated between experiments. Because of these differences in environment and experimental techniques, a series of experiments was conducted to determine if any of these variables affect the absorbability of fatty acid mixtures derived from hydrolyzed lard or beef tallow. EXPERIMENTAL PROCEDURE AND RESULTS
The fatty acid mixtures were analyzed for their fatty acid composition by subjecting the methyl esters of the fatty acids to gas liquid partition chromatography at 190°C. using a 2 meter X0.25 inch diameter column containing succinate polyester of diethylene-glycol as the liquid phase, 3 Alcoholic KOH contained one gram of KOH for each 5 ml. of 50% ethanol.
Ingredients
Experiment 1 A
% •—
Corn, ground 27.8 Glucose 1 Soybean meal (50% protein) 35.0 Isolated soybean protein 8 1.0 Fish meal 5.0 2.5 Whey, dried Corn distillers solubles 2.5 2.0 Alfalfa meal, dehydrated DL-Methionine 0.4 Glycine Cellulose 2.2 Dicalcium phosphate Limestone 1.0 Mineral mix#l 3 2.0 Vitamin mix #1 4 1.1 CrjOs bread' 1.0 Glucose and/or fatty acid mixture 16.5
— —
Experiment 2 B
%
14.9 10.0 7.0 25.0 5.0 2.0 2.5 2.0 0.3
—
4.0 2.2 1.0 1.1 1.1 1.0 20.0
C
% 32.0
— • — — . — — 0.7
35.47
0.3 3.0 3.28 1.25 2.0 1.1 1.0 20.0
1 Cerelose, Corn Products Company, New York. * C-l Assay Protein, Archer-Daniels-Midland, Minneapolis. * Mineral mix #1 supplies, per 100 gm. diet: gm.: NaCI, 0.8; KC1, 0.5; MgSO., 0.25; KHsPCU, 0.2; CaCOa, 0.1807; mg.: MnSCvEM), 30.0: FeS04-7HsO, 30.0; CuSO<-5H20, 3.0; ZnO, 6.0; Nal, 0.209; NasSeOs, 0.022; NaMo04-2HiO, 0.1. * Vitamin mix #1 supplies, per 100 gm. diet: vitamin A (stabilized), 1,000 IU; vitamin Dj, 150 ICU; vitamin E, 11.0 IU;_ mg.: choline CI, 200; niacin, 4.0; Ca pantothenate, 2.0; thiamine-HCl, 1.0; riboflavin, 1.0; pyridoxine-HCl, 1.0; menadione, 0.25; folic acid, 0.2; biotin, 0.03; vitamin Bn, 0.005; glucose (40 mesh screen) to provide 1.1 gm. of mix per 100 gm. of diet. 5 CnOa bread—30% CreOs in wheat flour, mixed with water to a thin dough, dried at 70°C. and ground to a fine powder.
and a thermister detector. Helium was used as the carrier gas at a flow rate of 80 mm. per minute. Except when otherwise noted, all chicks in each experiment were fed a lowfat basal diet similar to diet B, Table 1, for a period of one week. At this time they were allotted on the basis of body weight to the experimental groups. In all but the first experiment duplicate groups of 8 chicks each were fed each of the experimental diets for three weeks. Feed and water were supplied ad libitum over the four week experimental period. White Plymouth Rock chicks from a commercial hatchery were used in all but the first experiment; in this experiment R I R X B P R crossbred chicks were compared to the White Plymouth Rock chicks. The chicks were housed in electricallyheated, thermostatically-controlled battery brooders with raised wire screen floors. Excreta collections were made at
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
A series of four experiments was conducted. The fatty acids used in these experiments were prepared by hydrolysis of either lard or beef tallow. Approximately 18 kg. of fat were hydrolyzed at one time, using 150 ml. of alcoholic KOH 3 for every 100 gm. of fat. The solution was refluxed 5 hours in a steam kettle under a large condenser. After hydrolysis the mixture was cooled and slowly acidulated with diluted sulfuric acid. The free fatty acids were allowed to separate from the acid-water seat, the latter was removed and the fatty acids were washed 5 times with water. After complete separation of the final water wash, which was discarded, 0.0125% ethoxyquin was added to the fatty acid mixture which was stored in cans under nitrogen at 0°C. until used. Each preparation of fatty acid was titrated with standard sodium hydroxide solution to demonstrate complete hydrolysis.
TABLE 1.—Experimental basal diets
1148
R. J. YOUNG, R. L. GARRETT AND M. GRIFFITH TABLE 2.—Experimental basal diets Experiment 3 Ingredients
28% Protein D
E
%
%
Experiment 4
24% Protein
30% Protein
24% Protein
K
%
%
Ground corn 33.0 25.2 Glucose1 47.4 38.9 17.7 16.2 42.0 Protein premix A2 51.3 51.3 42.0 3 Protein premix B Isolated soybean protein' 2.5 3.3 Dicalcium phosphate 2.2) Limestone 1.0 Mineral mix #1 6 2.0 •Constant ingredients in all diets 6 Vitamin mix #1 1.1 1.0 Cr20;, bread7
M
%
%
%
%
18.7 20.0 54.0
— 36.85 54.0 1.85
32.3 20.0 40.4
— 49.11 40.4 3.19
Cerelose, Corn Products Company, New York. Protein premix A contains in gms./lOO gms.: soybean meal (50% protein), 68.23; isolated soybean protein4, 8.77; fish meal (60% protein) 9.75; corn distillers solubles, 4.87; dried whey, 3.90; dehydrated alfalfa meal, 3.90; DL-methionine, 0.58. This premix contains 50.8% protein and 1,192 metabohzable energy Calories per pound. 3 Protein premix B, similar to premix A above but contains 11.47% isolated soybean protein and therefore contains 52.6% protein and 1,190 metabohzable energy Calories per pound. 4 C —1 Assay Protein, Archer-Danie's-Midland, Minneapolis. 6 See footnote 3, Table 1. 6 See footnote 4, Table 1. 7 See footnote 5, Table 1.
four 24-hour periods between the 24th and 28th day. Immediately after collection the excreta were frozen. At the end of four days the excreta samples were combined, homogenized in a Waring blendor and dried at 70°C. in a forced air oven. Analyses were made on both the diet and the dried excreta for moisture, total lipids and chromium. Chromic oxide was incorporated in each diet as an index substance, thus eliminating the need for quantitative collection of excreta. The methods for processing excreta, conducting chemical determinations for chromium, fat and moisture, and computing fat absorbability from these data have been described by Hill et al. (1960), Renner and Hill (1960) and Young (1961). The method used for the determination of fecal fats measures all lipid fractions including triglycerides, free fatty acids and any fatty acids present in the form of soaps.
In each experiment chicks were fed diets containing the test fatty acid and other groups of chicks received a similar diet containing an equivalent amount of glucose in place of the fatty acid. The latter treatments were included for purposes of determining endogenous fat excretion and absorbability of the fat in the constant ingredients for each experimental diet. Fumigation of the animal laboratory and equipment was carried out immediately after cleaning by reacting 320 grams of potassium permanganate with 590 grams of formaldehyde for every 1,000 cu. ft. of laboratory space. The humidity in the room was increased by the simultaneous use of steam. Experiment 1. This experiment was designed to determine if there was a difference in fatty acid absorbability between White Plymouth Rock and R I R X B P R chicks. In this.experiment triplicate lots of
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
1
2
1149
ABSORBABILITY OF FATTY ACIDS
Experiment 2. Chicks in this experiment were fed either the practical or the purified basal diets B and C, respectively (Table 1), in which 20% lard fatty acids were subT A B L E 3.—Absorption of hydrolyzed animal by two different breeds of chicks (Experiment 1)
fats
Average weight, 4 weeks
rF e( .e,QJ / Il Iu , / gam
15% Lard fatty acids White Plymouth Rocks RIRXBPR'
644 434
1.38 1.42
87 87
89 87
15% Tallow fatty acids White Plymouth Rocks RIRXBPR
589 434
1.53 1.55
66 70
68 72
Treatment
1
Fat absorption 2 weeks 4 weeks
%
Rhode Island Red and Barred Plymouth Rock crossbreed.
T A B L E 4.—Absorption of lard fatty acids when fed for either two weeks or three weeks prior to fecal collection (Experiment 2) Number
Absorption
Treatment
™**™ t a t t y acids
Basal Basal <
L a r d f a t t y acids, 2 0 % L a r d f a t t y acids, 2 0 %
2 3
1
% 73 76
% 76 81
Basal diets shown in T a b l e 1.
stituted for glucose on a weight for weight basis. The chicks were fed the low fat basal diets containing glucose for either one or two weeks, followed by a three and two week feeding period, respectively, in which the diets contained the lard fatty acids. Chicks fed the diet containing the lard fatty acids for three weeks showed a significantly greater absorbability of the fatty acids than chicks fed the same diet for a two week period (Table 4). These results also showed that the absorbability of lard fatty acids when fed for either 2 or 3 weeks was higher in those chicks fed the basal diet made up of the practical ingredients (Diet B, Table 1) as compared to those fed purified diet C. Experiment 3. The third experiment was designed to compare the major differences in the experimental diets used by Young (1961) as compared to Renner and Hill (1961). The differences compared were the amount of protein, the use of corn vs. glucose as the major source of carbohydrate, and the isocaloric substitution of the fatty acids for glucose as compared to a weight for weight substitution for glucose in the test diets. The 28% protein diet (Diet A, Table 1) containing 16.5% glucose, was fed to all chicks for the first week. At this time they were allotted on a weight basis to the experimental groups. Duplicate lots of chicks were fed either a 24% or a 28% pro-
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
each breed with 15 chicks per lot were fed experimental basal diet A (Table 1) supplemented with hydrolyzed lard or beef tallow (15%) in place of glucose on a dry weight basis. The chicks were fed the diets containing the fatty acids from one day of age, and fecal collections were made at both the 2 and 4 week periods of the experiment. This experiment was conducted in a laboratory which had just been fumigated. The results are summarized in Table 3. They show that there is no difference between the two strains of chicks in their ability to utilize lard fatty acids or beef tallow fatty acids. Both strains showed a slightly greater absorbability of the tallow fatty acids at 4 weeks of age as compared to the absorbability measured at 2 weeks of age. However, the difference between the two age groups was not as great as that observed by Renner and Hill (1960) for tallow. No differences were observed in the absorbability at 2 and 4 weeks with chicks fed the lard fatty acids. The absorbability values found in this experiment compared favorably with those reported by Young (1961) for both the lard and beef tallow fatty acids.
1150
R. J. YOUNG, R. L. GARRETT AND M.
tein diet with either ground corn or glucose as the primary source of carbohydrate (Diets D , E, F, G, Table 2). Each diet was fed with and without lard fatty acids substituted weight for weight for glucose on a dry weight basis. I n addition, lard fatty acids were substituted isocalorically for glucose at both protein levels. Chicks were fed the experimental diets from 7 to 28 days of age, and excreta collections were made during the fourth week of the experiment. This experiment was conducted in an animal laboratory which had just been cleaned and fumigated.
( P < 0 . 0 5 ) when fed in the 2 8 % protein diets as compared to the 2 4 % protein, regardless of the type of carbohydrate. Within each protein level the use of corn as a source of carbohydrate in place of glucose significantly ( P < 0 . 0 1 ) improved the absorbability of the lard f a t t y acids. This was in contrast to the isocaloric substitution of the lard fatty acids for glucose which gave a lower absorbability value for these fatty acids at both levels of dietary protein. I t appears t h a t the absorbability value for beef tallow fatty acids must be influenced in a similar manner. The absorbability value for beef tallow fatty acids was significantly higher when these fatty acids were fed in the 2 8 % protein diet with corn as the carbohydrate, as compared to t h a t obtained in the 2 4 % protein diet with glucose as the carbohydrate. T h e significant decrease in absorbability of the lard fatty acids substituted isocalorically for glucose in the 2 4 % protein diet appears to be in conflict with the observation t h a t increasing the protein level of the diet increases the absorption of lard fatty acids. On the other hand, it is possible t h a t markedly reducing the amounts
TABLE 5.—Effect of level of protein and source of carbohydrate on the utilization of animal fatty acids (Experiment 3) Treatment
M.E. Calorie ."protein ratio1
Weight, 4 weeks
Feed/lb. gain
Absorbability
%
gms.
28% Protein diet 1. 15% Lard fatty acids+glucose 2. 15% Lard fatty acids+corn 3. 15% Lard fatty acids (isocaloric) 4. 15% Tallow fatty acids+corn
51 53 43 51
644 638 618 633
1.64 1.55 1.82 1.61
74"2 82 d 72»b 74a
24% Protein diet 5. 15% Lard fatty acids+glucose 6. 15% Lard fatty acids+corn 7. 15% Lard fatty acids (isocaloric) 8. 15% Tallow fatty acids+glucose
63 63 54 61
650 640 624 654
1.69 1.63 1.66 1.67
71 b 78" d 64 ° 66 b °
1 1
Calories of metabolizable energy per pound of diet divided by the percentage protein in the diet. Absorbability values with the same letter superscript are not significantly different. (Duncan, 1955)
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
The effects of the various treatments are summarized in Table 5. Excellent growth and feed conversion were obtained. I n making comparisons of the feed conversion values it should be noted t h a t there were significant changes in the energy: protein ratios due to the changes in protein levels and the methods of substitution of fat. These d a t a show t h a t level of protein, type of carbohydrate and method of substitution of the lard fatty acids all significantly influenced the absorbability of lard fatty acids. The absorbability of the lard fatty acids was significantly higher
GRIFFITH
1151
ABSORBABILITY OF FATTY ACIDS
and which also contained chicks of various ages. However, this was a relatively new laboratory and was not the same building which housed Experiments 1, 2 and 3. Chicks were fed diet A (Table 2) for the first week, whereupon they were allotted to experimental groups on an equal weight basis. Duplicate groups of 8 chicks in both the fumigated and non-fumigated laboratories were fed the various experimental diets containing the lard fatty acid both with and without a mixture of three antibiotics (Table 6). I n addition duplicate lots of 3 chicks each in both the fumigated and non-fumigated laboratories were fed each of the basal low-fat diets (J, K, L and M, Table 2) with and without antibiotics for a total of 16 low fat control diets. Correction for endogenous fat and fecal fat contributed by the constant diet ingredients was made from data obtained from the appropriate control treatment. There were no significant differences in
TABLE 6.-—Effect
of environment and dietary changes on the absorption of lard fatty acids by the chick (Experiment 4) Plus antibiotic I
No antibiotic Ave. wt., 4 wks. 30% Protein basal Non-fumigated laboratory 20% Lard fatty acids+glucose 20% Lard fatty acids+corn
Feed/lb. gain
gms.
Absorbability
Ave. wt.., 4 wks.
%
gms.
Feed/lb. gain
Absorbability
%
625 668
1.62 1.52
732 73
713 677
1.45 1.44
75' 73
Fumigated laboratory 20% Lard fatty acids+glucose 20% Lard fatty acids+corn
694 668
1.50 1.48
77 74
712 691
1.45 1.47
81 81
24% Protein basal Non-fumigated laboratory 20% Lard fatty acids+glucose 20% Lard fatty acids+corn
670 652
1.56 1.57
69 72
703 668
1.48 1.46
72 72
Fumigated laboratory 20% Lard fatty acids+glucose 20% Lard fatty acids+corn
679 665
1.60 1.56
69 73
697 700
1.52 1.43
78 75
1
50 p.p.m. each of penicillin, zinc bacitracin, chlortetracycline. Analyses of variance of this experiment taking into account the factorial arrangements of the treatments showed a highly significant (P<0.01) effect from the fumigated vs. the non-fumigated laboratory, from the 30% protein vs. the 24% protein diet and from the use of the antibiotics. The Laboratory times Antibiotic interaction was the only one out of 11 interactions which was significant (P<0.05). 2
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
of carbohydrate in the diet, by the isocaloric substitution technic may reduce the absorption of the lard fatty acids. Experiment 4. The fourth experiment in this series was conducted to determine the effect of fumigation of the chick laboratory and the effect of dietary antibiotics on the absorption of lard fatty acids. I n this experiment chicks were fed the basal diets J, K, L and M (Table 2) in which the 2 0 % lard fatty acids were substituted for glucose on a weight for weight basis. The protein level of the high protein diet was increased to 3 0 % protein in an a t t e m p t to accentuate the difference due to protein level. In addition the lard fatty acids were substituted for glucose at 2 0 % of the diet instead of 1 5 % in order to have a greater percentage of the calories in the diet supplied by the fatty acids. The complete experiment was duplicated in a fumigated laboratory and in a laboratory in which chicks had been housed previously
1152
R. J. Y O U N G , R. L. G A R R E T T AND M.
growth or feed conversion of chicks fed the various low fat diets except for a small growth response of chicks fed the diets containing the antibiotics. The average 4 week weight and feed conversion of 8 treatments without antibiotics was 665 gm. with 1.77 gm. of feed per gm. of gain as compared to an average of 685 gm. with 1.74 for the average feed conversion for the 8 treatments receiving the antibiotics.
The results of feeding lard fatty acids under these various conditions are summarized in Table 6. A highly significant ( P < 0 . 0 1 ) increase in absorbability of the lard fatty acids occurred under the following conditions: (1) when the chicks were housed in the fumigated laboratory as compared to those in the non-fumigated laboratory; (2) when the lard fatty acids were fed in a high protein diet versus a low protein diet; (3) when antibiotics were included in the diet versus no antibiotic added to the diet. I t should be noted t h a t a laboratory-time-antibiotictreatment interaction was observed which was significant a t the P < 0 . 0 5 level of probability showing t h a t the improvement in the absorbability of the lard fatty acids due to the addition of antibiotics was greatest in those chicks housed in the fumigated laboratory. In this experiment there was no effect of the type of carbohydrate on the absorbability of the lard
fatty acids. This was in contrast to the results observed in experiment 3, where the use of corn in place of glucose significantly improved the utilization of lard fatty acids. At present there is no explanation for this observed difference in the two experiments. DISCUSSION The results of these experiments show t h a t the absorbability of lard and beef tallow fatty acids can be significantly affected b y dietary and environmental conditions. The most significant of these factors is the level of protein in the diet. In every case there was an improvement in absorbability of both the beef tallow and the lard fatty acids when the level of protein in the diet was increased from 24 to 2 8 % or 24 to 3 0 % . Similar observations have been made in the rat. Barnes et al. (1944) fed triglycerides to rats and observed a higher fat digestibility in diets containing 3 0 % protein as compared to those containing 1 4 % protein. Carroll and Richards (1958) observed t h a t the digestibility of erucic acid by the r a t was improved as the protein level in the diet was increased. I n one experiment a significant improvement in absorbability occurred when corn was used as the principal source of carbohydrate as compared to glucose. However, this effect of carbohydrate was not observed in the fourth experiment, and therefore cannot be considered as a consistent variable. Intestinal a n d / o r environmental microflora apparently have a significant effect on the absorbability of these animal fatty acids, since the absorbability is always higher in those chicks which are reared in a laboratory which has just been recently fumigated as contrasted to chicks reared in a laboratory which has housed a number of experiments and contains
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
The endogenous fat excretion was not influenced b y antibiotics, environment or level of protein. However, the chicks fed all diets containing corn excreted more fecal fat (2.27% of excreta) than those fed diets containing glucose (1.45% of the excreta). This difference was expected and was of the same magnitude as t h a t observed in the other experiments. I t was due in p a r t to the fact that the low fat corn diet contained 2.38% fat while the low fat glucose diets contained 1.16% fat.
GRIFFITH
ABSORBABILITY OF FATTY ACIDS
The results of these experiments show that the absorbability of hydrolyzed lard and beef tallow can be influenced by a number of environmental and dietary conditions. Apparently many or some of these effects are additive. Therefore the difference in absorbability of these two sources of fatty acids observed by Renner and Hill (1961) and Young (1961) under the two different experimental conditions which were described can probably be attributed to a number of individual factors. These factors appear to be sufficiently additive to cause a marked differ-
ence in the absorbability values of lard and beef tallow fatty acid mixtures. SUMMARY
A series of experiments was conducted with chicks to determine environmental and dietary conditions which affect the absorbability of lard and beef tallow fatty acids. The absorbability of lard fatty acids was found to be increased when fed in a 28% or 30% protein diet as compared to a 24% protein diet, and when fed for a three week period prior to fecal collection, rather than for a two week period. Absorbability was higher when the fatty acids were substituted for glucose on a weight for weight basis rather than isocaloric substitution. The use of corn as a major source of carbohydrate rather than glucose improved absorption in one experiment, but this variable did not appear to have a consistent effect. There was no difference in absorption of these fatty acids in two breeds of chicks tested. The rearing of chicks in a fumigated laboratory significantly improved the absorbability of lard fatty acids, particularly if the fatty acids were fed in a high protein diet. The combination of three antibiotics in the diet improved the absorbability of lard fatty acid particularly if the chicks were reared in a fumigated laboratory. These factors appear to be sufficiently additive to cause a marked difference in the absorbabilities of lard fatty acid or beef tallow fatty acids in the chick, depending on the specific conditions of the experiment. REFERENCES Afifi, M., 1959. Uber den Einfluss antibiotischer Wirkstoffe in verschiedenen Dosierrungen auf Kiikenwachstum und Futterverdaulichkeit. Arch. of Kleintierzucht, 23: 404-408. Barnes, R. H., M. F. Primrose and G. O. Burr, 1944. The influence of the protein content of the diet upon fat digestibility. J. Nutrition, 27: 179-184.
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
chicks of various ages. Donaldson (1962) observed the greatest growth response to 10% added animal fat occurring in chicks reared in new electrically heated batteries as contrasted with chicks reared in old batteries. However, it is not known if the improved growth observed by Donaldson was due to an improvement in the absorbability of the dietary fat. The relationship of intestinal microflora to lard fatty acid absorption is also evident by the response to antibiotic. It was of interest to see that the greatest response to antibiotic occurred in those chicks housed in a fumigated laboratory. It would appear that the microflora which existed in the laboratory which had just been fumigated was more susceptible to antibiotic control than the microflora which develop over a period of time in the non-fumigated laboratory. Afifi (1959) observed an improvement in growth, feed utilization and digestibility of fat in 4 week old chicks fed either 25 p.p.m. aureomycin or 40 p.p.m. penicillin. Terramycin was without effect. Supplee (1960) observed that turkey poults showed a 20% increase in growth due to the addition of 13% corn oil to the diet in the presence of 50 p.p.m. of oleandomycin and only a 10% increase in the absence of the antibiotic.
1153
1154
R. J. YOUNG, R. L. GARRETT AND M. GRIFFITH
Carroll, K. K., and J. F. Richards, 1958. Factors affecting digestibility of fatty acids in the rat. J. Nutrition, 64: 411-424. Donaldson, W. E., 1962. The response of chicks to dietary animal fat in new and old environments. Poultry Sci. 41: 1106-1108. Duncan, D. B., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Hill, F. W., D. L. Anderson, R. Renner and L. B. Carew, Jr., 1960. Studies of the metabolizable energy of grain products for chickens. Poultry Sci. 39:573-579.
Renner, R., and F. W. Hill, 1960. The utilization of corn oil, lard and tallow by chickens of various ages. Poultry Sci. 39: 849-854. Renner, R., and F. W. Hill, 1961. Factors affecting the absorbability of saturated fatty acids in the chick. J. Nutrition, 74: 254-258. Supplee, W. C , 1960. The effect of antibiotic supplementation on the response of poults to dietary corn oil. Poultry Sci. 39: 227-229. Young, R. J., 1961. The energy value of fats and fatty acids for chicks. 1. Metabolizable energy. Poultry Sci. 40:1225-1233.
E. J. WLADYKA, L. E. DAWSON AND R. W. WALKER Departments of Food Science and Microbiology 6* Public Health, Michigan State University, East Lansing, Mich. (Received for publication March 13, 1963)
A
PROBLEM of major concern in the marketing of shell eggs is the heavyfinancial loss suffered annually by producers, processors and consumers due to soiled eggs. An economically effective means of removing the soil from dirty eggs would not only present a visibly cleaner product, but should also reduce the incidence of bacterial spoilage. In general, eggs cleaned by existing commercial procedures have not been as satisfactory in marketing channels as naturally clean eggs. For this reason, new or improved techniques should be investigated. According to Stuart and McNally (1943), shell eggs are generally sterile when laid, thus microbial spoilage of eggs encountered in commercial distribution channels is mainly due to the invasion of the egg by spoilage-producing organisms after the egg has been laid. Fromm and Munroe (1960) reported that interior quality and rate of bacterial contamina1 Michigan Agricultural Journal Article No. 3130.
Experiment
Station
tion are related to the permeability of the egg shell. Stuart and McNally (1943) indicated that the shell membrane may be more important as an agent in preventing contamination of the interior of the egg than the mucoid or "bloom" covering the shell. Walden et al. (1956) reported tracer experiments in which the egg shell membrane restrained the passage of microorganisms for periods of time up to 20 hours. High frequency sound waves transmitted throughout a cleaning fluid cause cavitation in the liquid. The cavitation, as reported by Johnson (1929) consists of the formation of thousands of microscopic bubbles within a liquid cleaning medium. The formation and collapse of these cavitations produce a powerful scrubbing action on soil (Carlin, 1949). Crawford (1955) reported that water was an excellent medium for ultrasonic cleaning. Murdock (1956) suggested that frequencies just above human audibility (20 Kc./sec.) were the most effective for cleaning. For a given power input, cavita-
Downloaded from http://ps.oxfordjournals.org/ by guest on April 17, 2015
The Influence of Ultrasonic Treatment on Egg Quality1