- Email: [email protected]
Restricted Feeding of Pullets
Restricted Feeding of Pullets EFFECT OF DURATION AND TIME OF RESTRICTION ON THREE-YEAR LAYING HOUSE PERFORMANCE 1 H. L. FULLER AND W. S. DUNAHOO2 Division of Poultry Husbandry, University of Georgia, Athens, Georgia (Received for publication January 12, 1962)
ESEARCH on the effect of restricted duction of chickens subjected to restricted - feeding of young chickens was re- feeding for varying lengths of time during viewed recently by Gowe et al. (1960) and their growing period. An effort was also summarized in a previous report by Fuller made to find a physiological basis for any (1962). Most of this research has been effects that restricted feeding might have concerned only with the effects of restricted on subsequent reproductive performance. feeding upon traits having economic imporEXPERIMENTAL PROCEDURE tance and consequently is usually content One thousand White Leghorn pullet with first-year egg production and related chicks were divided into 10 pens and characteristics such as age at maturity, brooded under uniform conditions to 6 mortality, and egg size. Since the work reweeks of age. At that time they were inported herein was initiated, Hollands and dividually weighed and randomly assigned Gowe (1961) have reported that producto 5 different treatments, 2 pens per treattion was increased in both the first and ment, for the growing period as follows: second laying year by restricted feeding during the growing period. Period of Restriction Treatment None Physiological bases for differences in lay1 6-12 weeks 2 ing house performance attributable to re6-18 weeks 3 stricted feeding of growing pullets also has 6-24 weeks 4 received too little attention. Progress made 12-24 weeks S in this area by biologists working with During the period shown feed was reother species was noted by Fuller (1958) stricted to 9 Ibs./lOO birds/day which was and citations appear elsewhere in this paper the average amount consumed at 6 weeks where applicable. There is also insufficient of age. The diet used during the growing evidence on the length of time or age at period (Table 1) was calculated to contain which growing chickens should be re21% protein and 937 Calories of producstricted in feed intake in order to obtain tive energy per pound; whereas, the ration the maximum response in egg production used to determine 42 nd day feed consumpor longevity. tion was the commercial chick starter raIn this experiment a comparison was tion that was used during the first 6 weeks made of first, second, and third year proand which contained slightly higher nutrient and energy levels. Since the level of 1 Journal Paper No. 219 of the College Experirestriction was arbitrary the difference in ment Station, University of Georgia College of diets was considered unimportant except Agriculture Experiment Stations. to note that the energy and nutrient intake 2 Present address: Otis Feed Co., Parsonburg, were thus restricted to slightly below the Md. 1306
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
R
RESTRICTED FEEDING OF PULLETS TABLE 1.—Growing ration Ingredient Yellow corn Soybean oil meal (50% protein) Fish meal (menhaden) Oats Alfalfa meal (18% protein) Distillers dried solubles Limestone Deflourinated phosphate (34% Ca, 17% P) Salt Trace mineral mixture 1 Vitamin mixture 2 Coccidiostat3
% 60.25 22.00 5.00 5.00 2.00 1.50 1.75 1.00 0.35 0.15 1.00
+
1
Delamix® (Limecrest Products Co.) contained: manganese, 6.0%; iron, 2.0%; iodine, 0.12%; cobalt, 0.02%, and calcium, 26.5%. 2 Vitamin mixture (per pound of feed): vitamin A, 1890 I.U.; vitamin D 3 , 500 I.C.U.; riboflavin, 1.5 mg.; pantothenic acid, 3 mg.; niacin, 15 mg.; choline chloride, 150 mg.; vitamin B12, 6 meg.; alpha tocopheryl acetate, 10 mg.; menadione sodium bisulfite, 1 mg.; DL methionine, .025%; oxytetracycline, 5 mg.; arsanilic acid, 45 mg. 3 Nitrofurazone, 0.0055% and furazolidone 0.0008% (Bifuran®) included from 6 to 10 weeks of age.
(Snedecor, 1959) and in instances where treatment differences were significant the multiple range test of Duncan (1955) was applied. RESULTS AND DISCUSSION
Growth Rate. Average body weights are shown in Table 2. Growth rate was reduced during the periods of restriction in a very consistent pattern. As the pullets became older the restriction became more severe, since the quantity of feed given to the birds was kept constant at the rate that it was consumed at 6 weeks of age. This imposed the most severe restriction on the group that was full-fed to 12 weeks of age and then cut-back to the 6-week consumption rate. Recovery was rapid after removing the restriction in every case and the growth curve during the recovery period was steeper than for the normal group at any time during its growing period (Fig. 1). This was most noticeable for birds restricted to 24 weeks of age and thus
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
42nd day intake level. Adequate feeder space was provided so that all birds could eat at one time. At 18 weeks of age each pen was randomly divided into two yielding 4 replicates for each treatment and the birds were moved into a 20-pen pole-type laying house. The growing ration was fed to each group until production commenced in that group or until 24 weeks of age whichever came first, after which they received a commercial laying ration, ad libitum. Artificial lights were used to maintain at least 14 hours of light per day during the entire laying period. The birds were weighed individually at 6 week intervals to 30 weeks of age, then again at 1 year of age and at 1,2, and 3 years of production. Records of egg production, mortality, and feed consumption were kept. Eggs were weighed one day each week during the first 4 months while egg size was increasing rapidly and on two consecutive days each month until the end of the first year, after which the weighing was discontinued. Ten bird samples were selected at random from each treatment for oxygen consumption studies and the same birds were used for the 18, 24, and 52-week measurements except where mortality prohibited. The apparatus used is described by Huston et al. (1962) and consisted of an enclosed chamber with a water seal large enough for one bird, a spirometer, and a kymograph for measuring the amount of 0 2 entering the chamber. C0 2 was removed chemically with a solution of saturated KOH. Test birds were starved for 24 hours prior to measurement and were placed in the chamber for a 15 minute pretest period to become quiescent prior to the IS minute test period. These times were reduced to 10 minutes each for the 24 and 52 week measurements after improving the apparatus. Data were tested by analysis of variance
1307
1308
H. L. FULLER AND W. S. DUNAHOO TABLE 2.—Body weight of White Leghorns as influenced by feed restriction Body wt. (lbs.)
1. 2. 3. 4. 5.
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
12 wk*
18 wk*
24 wk*
30 wk
52 wk
176 wk
1.97" 1.84b 1.80b 1.81 b 1.99a
2.85" 2.86* 2.65 b 2.50° 2.51"
3.61" 3.70 b 3.57" 2.67° 2.67°
4.00 4.00 4.05 3.82 3.95
4.35 4.40 4.37 4.24 4.36
4.76 4.68 4.77 4.44 4.63
* Average body weight differences highly significant (P<.01). a.b.c Weights in the same column followed by the same letters are not significantly different.
cantly lighter than the controls at 12 weeks of age but heavier at 24 weeks of age. On the other hand Aron (1911), working with dogs, found that when the growth of dogs was suppressed early in life by dietary restriction they still retained the ability to grow vigorously when the restriction was removed except when growth was suppressed beyond the adolescent period, in which case the capacity to grow was reduced. In this connection note that the birds which were restricted to 24 weeks of age attained final body weights which ap-
50* Prod.
3
F i r s t Egg
Pull-Fed Restricted 1
0L 6
12
18 Age in weeks
21*
30
FIG. 1. Growth and maturity of White Leghorn pullets as affected by restricted feeding.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
agrees with the reports of Osborne and Mendel (1915, 1916) who found that the growth impulse of rats could be retained and exercised at periods far beyond the age at which growth ordinarily had ceased. They also demonstrated that curves of "resumed growth" after periods of growth suppression (by restricted feeding) were steeper than the normal curve at any stage of its progress, and in many cases greater maximum weight was eventually attained. This latter phenomenon was exhibited in our work by group 2 which was signifi-
RESTRICTED FEEDING OF PULLETS
TABLE 3.—Effect of feed restriction on age of White Leghorns at sexual maturity^
Growing treatment 1 2 3 4 5
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
Age at sexual maturity* (days) 147" 145» 159b 179° 179°
* Treatment differences highly significant (P<.01). a,b,o Values not followed by the same letters are significantly different statistically. 1 Based upon average date of first egg in pens within each treatment.
TABLE 4.—Oxygen consumption of White Leghorns as influenced by feed restriction cc oxygen per lb. body wt. Growing treatment 18 wk* 1 2 3 4 5
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
346" 300*b 289b i
263b
" 24 wk
52 wkt
245 236 233 210 237
227" 193b 227" 200b 185b
1 Assumed to be same value as treatment 3 since both groups were treated the same to this time. * Treatment differences significant (P<.05). f Treatment differences highly significant (P < . 01). a b ' Values in the same column not followed by the same letters are significantly different.
different due to variation within treatment. At 52 weeks of age differences in oxygen consumption values among treatments were highly significant (P < .01). Values were again smaller for the more severely restricted pullets with one exception and no explanation can be offered for the high value for birds in treatment 3 (restricted 6 to 18 weeks). Thus a reduced rate of basal metabolism due to feed restriction appeared to persist far beyond the termination of restriction. Ingle et al. (1937) found that when certain members of Cladocera (water flea) species were starved for various periods from birth through the normal time of reproductive maturity and then full fed they exhibited a lower metabolic rate than those receiving unlimited food. They also found that the heart rate decreased during periods of inanition and that it increased but not to normal after returning to full feed. Since the restricted groups produced the same number of young, but later in life, and lived significantly longer than the controls, they concluded that a low metabolic rate was conducive to prolonged life in this species. Mortality. Mortality (Table 5) was slightly higher in the severely restricted groups than for the controls or less severely
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
proached those of the controls but did not surpass them. It was also notable that their rapid rate of recovery occurred during the time when they were also rapidly attaining maximum egg production (24 to 30 weeks). Age at Sexual Maturity. Time of first egg and attainment of 50% production (based upon pen averages within each treatment group) are indicated on the growth curves in Figure 1. Average age at first egg is also set forth in Table 3. Maturity was delayed from 0 to 4 weeks depending on the duration and time of restriction. This agrees with Bruins (1958) who pointed out that when feed restriction is removed prior to 20 weeks of age there is little if any delay in sexual maturity. The differences in age at sexual maturity were highly significant. Oxygen Consumption. Basal metabolic rate as illustrated by oxygen consumption is shown in Table 4. At 18 weeks oxygen consumption agrees closely with the level of feed intake and treatment differences were significantly different at the 5% level of probability. The more severely retarded groups consumed less oxygen per unit of body weight indicating a reduced rate of basal metabolism. At 24 weeks oxygen consumption appeared to be related to treatments with one exception (treatment 5) but treatment means were not significantly
1309
1310
H. L. FULLER AND W. S. DUNAHOO
TABLE 5.—Mortality among White Leghorn chickens restricted for varying time intervals
TABLE 7.—Ivffect of feed restriction on three year , production (starting at 1st egg for each group)1 Eggs/bird (hen-day basis)
Mortality (No. of birds)* Growing treatment
1 2 3 4 5
Growing treatment
Laying Year
Growing Period
1
2
3
Total
8 4 6 13 14
28 29 34 23 22
32 41 32 28 30
39 36 41 39 43
107 110 113 103 109
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
*200 started per treatment.
TABLE 6.—Ejfect of feed restriction on three year egg production (starting at 20 wks) Eggs/bird (heri-day basis) Growing treatment
1st yr.
2nd yr.
2nd yr. Cum.
1 2 3 4 5
227 227 227 224 222
171 172 178 193 180
398 399 405 417 402
N.S.
N.S.
Full-fed Restr. 6-12 wks Restr. 6-18 wks Restr. 6-24 wks Restr. 12-24 wks
Analysis of Variance a b
3rd yr.
3rd yr. Cum.
113 a a b 128 a b 124b 137 116 a
511 527 529 554 518
P<.05
N.S.
- : Values not followed by the same letter are significantly different ( P < . 0 5 ) .
Full-fed 227° Restr. 6-12 wks 227" Restr. 6-18 wks 235ab 3 Restr. 6-24 wks 242 b Restr. 12-24 wks 3 239 b
Analysis of variance P < . 01
2nd yr.
2 yr. Cum.
3rd yr. 2
Cum.
171 172 177 189 175
398 399 412 431 414
104 a 118 a b 112 a b 123 b 104 a
502 517 524 554 518
N.S. (P-C.10) P < . 0 5 ( P < . 1 0 )
1
Laying year started as follows: 1—21 wks., 2—21 wks., 3—23 wks., 4—25 wks., 5—25 wks. These times represent the average age at which the first egg was laid in the replicate pens of the respective groups. 2 11 mo. only. 3 Significantly different from treatments 1 and 2 at the 5 % level of probability. Also 4 significantly different from 3. a b ' : Values in the same column not followed by the same letters are significantly different.
above basis it would have to be concluded that no reproductive advantage occurred from restricted feeding. The work of MacIntyre and Aitken (1959) emphasized the need for adjusting the production period to allow for the delay in sexual maturity of the restricted groups. In this experiment starting the reporting period for egg production while two of the groups were still undergoing their growing treatment placed a penalty of approximately 4 weeks on the latter groups. Therefore, in Table 7, egg production is shown with the production period for each group started at the approximate date of sexual maturity for that group. When figured in this way a highly significant difference in favor of the groups restricted to 24 weeks of age was found during the first laying year and a significant difference again in the third year for group 4 restricted from 6-24 weeks. Two and three year cumulative production approached statistical significance (P < .10). Since the experiment was terminated at the same time for all groups it was necessary to move the reporting period back 4 weeks in groups 1 and 2, and 2 weeks in group 3, thus providing a uniform 11 month period in the "3rd year" column. It is felt that providing each group with a laying period of uniform length is not only
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
restricted groups during the period of restriction. This difference among groups was completely overcome by the end of the first laying year so that mortality at that time, and thenceforth, was similar for all treatments. Egg Production. Restricting pullets from 6-24 weeks at the level of feed intake attained at 6 weeks proved to be advantageous in terms of egg production. When starting the production period at 20 weeks of age for all groups (Table 6), this advantage did not become statistically significant until the 3rd year, although the restricted groups overcame the 4-week head start of the full-fed group by the end of the 1st laying year. This is the first report to the author's knowledge of three years egg production data in a restricted feeding experiment. If this experiment had been concluded at the end of the first laying year as is usually done, or even at the end of the second year, and reported on the
1 2 3 4 5
1st yr.
RESTRICTED FEEDING
OF P U L L E T S
1311
21
22
23
21*
25 26 Weeks of Age
27
28
I?
Jo
FIG. 2. Egg production and egg size as affected by restricted feeding.
justifiable but preferable as long as both methods of calculation are shown. Egg Size and Quality. Rapid attainment of large egg size is one of the advantages claimed for restricted feeding and there is perhaps more agreement on this point than any other. Figure 2 illustrates this phenomenon where egg weight and egg production for the control group and the 6-24 week restricted group are plotted against the same time axis. The restricted birds required only 3 weeks and 44% production whereas the control group required 7 weeks and 74% production to attain an egg size of 53 grams. The restricted groups had not yet attained the body weight of the control group at this time. After this time egg weights remained quite uniform among treatments and weighing was discontinued after 16 months of production. Table 8 shows the similarity of numbers
and pounds of eggs produced to 72 weeks of age on the various treatments. Egg quality measurements (Table 9) included shell thickness and interior quality as measured by Haugh units on all eggs produced on 2 consecutive days after the birds had been in production approximately one year. No differences due to treatment were observed. Feed Consumption. Table 10 shows feed TABLE 8.-
-Weight of eggs produced in first year of production
Growing treatment 1 2 3 4 5
Full-fed Restr. 6-12 wks Restr. 6-18 wks Restr. 6-24 wks Restr. 12-24 wks
No. eggs Total wt. per bird of eggs/bird (H.D. basis) (lbs.) 227 227 227 224 222
31.9 32.1 31.5 31.8 31.2
* Using same starting date (20 wks of age) for alj treatment.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
Egg Production
1312
H. L. FULLER AND W. S. DUNAHOO
TABLE 9.—Shell thickness and Haugh units as a measure of egg quality after 1 year of production
Growing treatment
Shell Thickness (.001 inch)
Haugh units
Full-fed Restr. 6-12 wks Restr. 6-18 wks Restr. 6-24 wks Restr. 12-24 wks
15.59 15.30 15.60 15.60 15.70
69.3 65.8 70.4 69.5 69.4
1 2 3 4 5
TABLE 10.—Feed consumption and utilization as affected by restricted feeding Feed consumption (lbs./bird) Growing treatment
1. 2. 3. 4. 5.
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
Feed conversion (Ibs./doz.)
Age at 1st egg (Wks)
6-24 wk
24-30
Day-old to first egg
21 21 23 25 25
17.1 17.0 15.9 12.9 13.3
11.7 11.5 11.6 11.2 11.9
15.0 14.8 16.3 16.5 16.9
"•*>: Values not followed by the same letter are significantly different (P<.05).
3 yr. prod. 6.31" 6.30» 6.05 s * 5.78 b 6.08*b
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
consumption for the entire growing period and feed conversion for the production period. Here again feed consumption is presented in 2 different ways. While there was an obvious difference in feed consumption to 24 weeks of age as a result of the restriction, the amount of feed required to grow the bird to sexual maturity, regardless of the age at maturity, was quite similar. Differences in feed conversion (lbs. of feed per dozen eggs) were highly significant and followed the same pattern as seen in egg production. While these differences may be attributed largely to differences in egg production, additional savings in feed may have resulted from the slightly smaller body weight of the 6-24 week restricted group. Practical Consideration. Obviously it is economically impractical to keep hens for 3 years for commercial egg production and in designing this experiment it was not anticipated that restricted feeding of pullets would alter greatly the practical economic life of the hens. This experiment
attempted to relate the effects of restricted feeding of growing chickens to findings in other species. To accomplish this it was necessary to observe egg production and mortality beyond the period that is normally observed when the duration of the experiment is limited by consideration of practical aspects only. When defining the laying year in the usual manner, based upon the same calendar dates, regardless of age at maturity, a significant difference in production was found only in the third laying year; although the severely restricted groups had overcome the delay in maturity, caused by the restriction, by the time they were 17 months old. Thus, these groups laid as many eggs in 11 months as the controls produced in 12 months. When charging the birds only for the time actually spent in the laying house (beginning at the approximate date of sexual maturity for each group) a highly significant increase in egg production was obtained during the first laying year as a result of restricted feeding from 6-24 weeks of age. Such a method of reporting is not impractical. Poultrymen can take advantage of this early "spurt" in egg production and egg size by properly planning their replacement schedule and simply extending the growing period by a few weeks. The extra time spent in the growing period was shown to require no more feed, so with little if any extra cost the poultryman
RESTRICTED FEEDING OF PULLETS
can utilize his laying houses to better advantage by reducing the long slow approach to peak production and egg size.
tive production approached statistical significance (P < .10) when calculated in this way. Treatment effect on egg size was evidenced only by larger initial eggs from pullets restricted to 24 weeks of age, with differences on any given calendar date not significant after the first few weeks. No statistical difference was found in amount of feed consumed by pullets to reach sexual maturity, but birds restricted more than 6 weeks required less feed per dozen eggs during the laying period. Mortality was higher in the severely restricted groups during the period of restriction and higher in the full-fed and less severely restricted groups during the early part of the laying period. Total mortality rates were not significantly different. No differences between experimental treatments were found in egg shell thickness or Haugh unit values of eggs when the birds had been in production for 12 months. REFERENCES Aron, H., 1911. Nutrition and growth, 1. Philippine J. Sci. 6 ( B ) : 1. Bruins, H. W., 1958. Energy restriction for replacement pullets. Feedstuffs, 30 (No. 39): 32-35. Duncan, D. G., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Fuller, H. L„ 1958. Restricted feeding of pullets for flock replacement. Proc. Nutr. Council, American Feed Mfrs. Assoc, Dec. 1-2, pp. 11-15. Fuller, H. L., 1962. Restricted feeding of pullets. 1. The value of pasture and self-selection of dietary components. Poultry Sci. (submitted for publication). Gowe, R. S., A. S. Johnson, R. D. Crawford, J. H. Downs, A. T. Hill, W. F. Mountain, J. R. Pelletin and J. H. Strain, 1960. Restricted versus full-feeding during the growing period for egg production stock. Brit. Poultry Sci. 1: 37-56. Hollands, K. G., and R. S. Gowe, 1961. The effect of restricted and full-feeding during confinement rearing on first and second year laying house performance. Poultry Sci. 40: 574-583.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
SUMMARY White Leghorn pullets were subjected to restricted feed intake for the following periods: none, 6-12, 6-18, 6-24 and 12-24 weeks of age. During these periods feed was limited to the average intake at 6 weeks of age. Egg production characteristics were observed for 3 years. Growth was retarded significantly in all groups but in every case recovery was rapid after removal of restriction and curves of growth recovery were steeper than the normal curve at any point. Where restriction was removed by 12 weeks of age this rapid recovery carried this group to a greater weight than the controls at 24 weeks of age. Where restriction was continued from 6 to 24 weeks of age body weight remained slightly below the controls for the entire 3 years. Basal metabolic rate as measured by 0 2 consumption was lowered by restricted feeding and the lowered rate appeared to persist 6 months after removal of restriction. Feed restriction delayed sexual maturity from 0 to 4 weeks depending upon the duration of restriction, but the deficit in early egg production was overcome in less than 12 months. Restricting pullets from 6 to 24 weeks of age resulted in increased egg production which was statistically significant only during the third year when the production period was calculated from 20 weeks for all groups. When the production period for each treatment was adjusted according to the different maturity dates a highly significant difference in favor of the groups restricted to 24 weeks of age was found during the first laying year, and a significant difference again in the third year for the group restricted from 6-24 weeks of age. Two and three year cumula-
1313
1314
H.
L.
FULLER AND W.
Huston, T. M., T. E. Botton and J. L. Carmon, 1962. The influence of high environmental temperature on immature domestic fowl. Poultry Sci: (In press). Ingle, L., T. R. Wood and A. M. Banta, 1937. A study of longevity, growth, reproduction, and heart rate of Daphnia longispina as influenced by limitations in quantity of food. J. Exp. Zoo. 76: 325-352. Maclntyre, T. M., and J. R. Aitken, 1959. The performance of laying hens reared on restricted
S.
DUNAHOO
and full-feeding programs. Can. J. Animal Sci. 39: 217-225. Osborne, T. B., and L. B. Mendel, 1915. The resumption of growth after long continuous failure to grow. J. Biol. Chem. 23.: 439. Osborne, T. B., and L. B. Mendel, 1916. Acceleration of growth after retardation. Am. J. Physiol. 40: 16. Snedecor, G. W., 1956. Statistical Methods. Fifth Edition, Iowa State College Press, 534 pp.
B. H A L L DAVIS AND CLAYTON C.
Louisiana State University, Baton Rouge,
BRUNSON
Louisiana
(Received for publication January 12. 1962)
W
AYS of preventing the decline of interior egg quality have been studied extensively by many research workers. Oil as a spray or dip has gained wide acceptance. It has been used for long term storage for many years (Spamer, 1931), and has been the subject of much recent investigation. Sauter et al. (1960), studied oil as a spray, a dip and as an aerosol spray and reported that dipping produced the best results. Aerosol spray did not appear to aid in maintaining quality except for a slight reduction in weight loss. Oil as a spray compared favorably with oil as a dip in the reports of Schwall et al. (1961), Swanson et al. (1958), and Stadelman and Wilson (1958). A more recent method of preserving quality has been the use of cellophane as a carton overwrap. Some of the claims made for cellophane are, (1) it is moisture proof, thereby keeping moisture in the egg, (2) it is gas proof, therefore carbon dioxide stays inside the egg, (3) it is transparent and thus allows the consumer to view the contents of the package, and (4) it is attractive. Davis and Beeckler (1960) studied vari-
ous grades of cellophane, Cryovac, and polyethylene as an overwrap, as well as the various oil treatments in preventing quality decline. They found that oil submersion and Cryovac were very effective in preventing quality loss. Cellophane and polyethylene were less efficient in maintaining quality. These results agree in general with work reported by Fletcher et al. (1957), and Davis (1959). In this study the objectives were to test the effectiveness of oil and cellophane in, (1) preventing interior quality decline, (2) protecting against weight loss, and (3) preventing the absorption of odor at three temperature environments. MATERIALS AND METHODS A total of 672 eggs was used in the study. A 24-egg sample was broken to determine initial quality. The remaining eggs were divided into three lots of eighteen dozen each. Three treatments were used which were as follows: (1) eighteen dozen eggs were placed in 2 X 6 cartons with no shell or carton treatment, (2) eighteen dozen eggs were placed in 2 X 6 cartons which were overwrapped with a
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
Relative Effectiveness of Oil and Cellophane in Protecting Eggs
ESEARCH on the effect of restricted duction of chickens subjected to restricted - feeding of young chickens was re- feeding for varying lengths of time during viewed recently by Gowe et al. (1960) and their growing period. An effort was also summarized in a previous report by Fuller made to find a physiological basis for any (1962). Most of this research has been effects that restricted feeding might have concerned only with the effects of restricted on subsequent reproductive performance. feeding upon traits having economic imporEXPERIMENTAL PROCEDURE tance and consequently is usually content One thousand White Leghorn pullet with first-year egg production and related chicks were divided into 10 pens and characteristics such as age at maturity, brooded under uniform conditions to 6 mortality, and egg size. Since the work reweeks of age. At that time they were inported herein was initiated, Hollands and dividually weighed and randomly assigned Gowe (1961) have reported that producto 5 different treatments, 2 pens per treattion was increased in both the first and ment, for the growing period as follows: second laying year by restricted feeding during the growing period. Period of Restriction Treatment None Physiological bases for differences in lay1 6-12 weeks 2 ing house performance attributable to re6-18 weeks 3 stricted feeding of growing pullets also has 6-24 weeks 4 received too little attention. Progress made 12-24 weeks S in this area by biologists working with During the period shown feed was reother species was noted by Fuller (1958) stricted to 9 Ibs./lOO birds/day which was and citations appear elsewhere in this paper the average amount consumed at 6 weeks where applicable. There is also insufficient of age. The diet used during the growing evidence on the length of time or age at period (Table 1) was calculated to contain which growing chickens should be re21% protein and 937 Calories of producstricted in feed intake in order to obtain tive energy per pound; whereas, the ration the maximum response in egg production used to determine 42 nd day feed consumpor longevity. tion was the commercial chick starter raIn this experiment a comparison was tion that was used during the first 6 weeks made of first, second, and third year proand which contained slightly higher nutrient and energy levels. Since the level of 1 Journal Paper No. 219 of the College Experirestriction was arbitrary the difference in ment Station, University of Georgia College of diets was considered unimportant except Agriculture Experiment Stations. to note that the energy and nutrient intake 2 Present address: Otis Feed Co., Parsonburg, were thus restricted to slightly below the Md. 1306
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
R
RESTRICTED FEEDING OF PULLETS TABLE 1.—Growing ration Ingredient Yellow corn Soybean oil meal (50% protein) Fish meal (menhaden) Oats Alfalfa meal (18% protein) Distillers dried solubles Limestone Deflourinated phosphate (34% Ca, 17% P) Salt Trace mineral mixture 1 Vitamin mixture 2 Coccidiostat3
% 60.25 22.00 5.00 5.00 2.00 1.50 1.75 1.00 0.35 0.15 1.00
+
1
Delamix® (Limecrest Products Co.) contained: manganese, 6.0%; iron, 2.0%; iodine, 0.12%; cobalt, 0.02%, and calcium, 26.5%. 2 Vitamin mixture (per pound of feed): vitamin A, 1890 I.U.; vitamin D 3 , 500 I.C.U.; riboflavin, 1.5 mg.; pantothenic acid, 3 mg.; niacin, 15 mg.; choline chloride, 150 mg.; vitamin B12, 6 meg.; alpha tocopheryl acetate, 10 mg.; menadione sodium bisulfite, 1 mg.; DL methionine, .025%; oxytetracycline, 5 mg.; arsanilic acid, 45 mg. 3 Nitrofurazone, 0.0055% and furazolidone 0.0008% (Bifuran®) included from 6 to 10 weeks of age.
(Snedecor, 1959) and in instances where treatment differences were significant the multiple range test of Duncan (1955) was applied. RESULTS AND DISCUSSION
Growth Rate. Average body weights are shown in Table 2. Growth rate was reduced during the periods of restriction in a very consistent pattern. As the pullets became older the restriction became more severe, since the quantity of feed given to the birds was kept constant at the rate that it was consumed at 6 weeks of age. This imposed the most severe restriction on the group that was full-fed to 12 weeks of age and then cut-back to the 6-week consumption rate. Recovery was rapid after removing the restriction in every case and the growth curve during the recovery period was steeper than for the normal group at any time during its growing period (Fig. 1). This was most noticeable for birds restricted to 24 weeks of age and thus
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
42nd day intake level. Adequate feeder space was provided so that all birds could eat at one time. At 18 weeks of age each pen was randomly divided into two yielding 4 replicates for each treatment and the birds were moved into a 20-pen pole-type laying house. The growing ration was fed to each group until production commenced in that group or until 24 weeks of age whichever came first, after which they received a commercial laying ration, ad libitum. Artificial lights were used to maintain at least 14 hours of light per day during the entire laying period. The birds were weighed individually at 6 week intervals to 30 weeks of age, then again at 1 year of age and at 1,2, and 3 years of production. Records of egg production, mortality, and feed consumption were kept. Eggs were weighed one day each week during the first 4 months while egg size was increasing rapidly and on two consecutive days each month until the end of the first year, after which the weighing was discontinued. Ten bird samples were selected at random from each treatment for oxygen consumption studies and the same birds were used for the 18, 24, and 52-week measurements except where mortality prohibited. The apparatus used is described by Huston et al. (1962) and consisted of an enclosed chamber with a water seal large enough for one bird, a spirometer, and a kymograph for measuring the amount of 0 2 entering the chamber. C0 2 was removed chemically with a solution of saturated KOH. Test birds were starved for 24 hours prior to measurement and were placed in the chamber for a 15 minute pretest period to become quiescent prior to the IS minute test period. These times were reduced to 10 minutes each for the 24 and 52 week measurements after improving the apparatus. Data were tested by analysis of variance
1307
1308
H. L. FULLER AND W. S. DUNAHOO TABLE 2.—Body weight of White Leghorns as influenced by feed restriction Body wt. (lbs.)
1. 2. 3. 4. 5.
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
12 wk*
18 wk*
24 wk*
30 wk
52 wk
176 wk
1.97" 1.84b 1.80b 1.81 b 1.99a
2.85" 2.86* 2.65 b 2.50° 2.51"
3.61" 3.70 b 3.57" 2.67° 2.67°
4.00 4.00 4.05 3.82 3.95
4.35 4.40 4.37 4.24 4.36
4.76 4.68 4.77 4.44 4.63
* Average body weight differences highly significant (P<.01). a.b.c Weights in the same column followed by the same letters are not significantly different.
cantly lighter than the controls at 12 weeks of age but heavier at 24 weeks of age. On the other hand Aron (1911), working with dogs, found that when the growth of dogs was suppressed early in life by dietary restriction they still retained the ability to grow vigorously when the restriction was removed except when growth was suppressed beyond the adolescent period, in which case the capacity to grow was reduced. In this connection note that the birds which were restricted to 24 weeks of age attained final body weights which ap-
50* Prod.
3
F i r s t Egg
Pull-Fed Restricted 1
0L 6
12
18 Age in weeks
21*
30
FIG. 1. Growth and maturity of White Leghorn pullets as affected by restricted feeding.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
agrees with the reports of Osborne and Mendel (1915, 1916) who found that the growth impulse of rats could be retained and exercised at periods far beyond the age at which growth ordinarily had ceased. They also demonstrated that curves of "resumed growth" after periods of growth suppression (by restricted feeding) were steeper than the normal curve at any stage of its progress, and in many cases greater maximum weight was eventually attained. This latter phenomenon was exhibited in our work by group 2 which was signifi-
RESTRICTED FEEDING OF PULLETS
TABLE 3.—Effect of feed restriction on age of White Leghorns at sexual maturity^
Growing treatment 1 2 3 4 5
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
Age at sexual maturity* (days) 147" 145» 159b 179° 179°
* Treatment differences highly significant (P<.01). a,b,o Values not followed by the same letters are significantly different statistically. 1 Based upon average date of first egg in pens within each treatment.
TABLE 4.—Oxygen consumption of White Leghorns as influenced by feed restriction cc oxygen per lb. body wt. Growing treatment 18 wk* 1 2 3 4 5
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
346" 300*b 289b i
263b
" 24 wk
52 wkt
245 236 233 210 237
227" 193b 227" 200b 185b
1 Assumed to be same value as treatment 3 since both groups were treated the same to this time. * Treatment differences significant (P<.05). f Treatment differences highly significant (P < . 01). a b ' Values in the same column not followed by the same letters are significantly different.
different due to variation within treatment. At 52 weeks of age differences in oxygen consumption values among treatments were highly significant (P < .01). Values were again smaller for the more severely restricted pullets with one exception and no explanation can be offered for the high value for birds in treatment 3 (restricted 6 to 18 weeks). Thus a reduced rate of basal metabolism due to feed restriction appeared to persist far beyond the termination of restriction. Ingle et al. (1937) found that when certain members of Cladocera (water flea) species were starved for various periods from birth through the normal time of reproductive maturity and then full fed they exhibited a lower metabolic rate than those receiving unlimited food. They also found that the heart rate decreased during periods of inanition and that it increased but not to normal after returning to full feed. Since the restricted groups produced the same number of young, but later in life, and lived significantly longer than the controls, they concluded that a low metabolic rate was conducive to prolonged life in this species. Mortality. Mortality (Table 5) was slightly higher in the severely restricted groups than for the controls or less severely
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
proached those of the controls but did not surpass them. It was also notable that their rapid rate of recovery occurred during the time when they were also rapidly attaining maximum egg production (24 to 30 weeks). Age at Sexual Maturity. Time of first egg and attainment of 50% production (based upon pen averages within each treatment group) are indicated on the growth curves in Figure 1. Average age at first egg is also set forth in Table 3. Maturity was delayed from 0 to 4 weeks depending on the duration and time of restriction. This agrees with Bruins (1958) who pointed out that when feed restriction is removed prior to 20 weeks of age there is little if any delay in sexual maturity. The differences in age at sexual maturity were highly significant. Oxygen Consumption. Basal metabolic rate as illustrated by oxygen consumption is shown in Table 4. At 18 weeks oxygen consumption agrees closely with the level of feed intake and treatment differences were significantly different at the 5% level of probability. The more severely retarded groups consumed less oxygen per unit of body weight indicating a reduced rate of basal metabolism. At 24 weeks oxygen consumption appeared to be related to treatments with one exception (treatment 5) but treatment means were not significantly
1309
1310
H. L. FULLER AND W. S. DUNAHOO
TABLE 5.—Mortality among White Leghorn chickens restricted for varying time intervals
TABLE 7.—Ivffect of feed restriction on three year , production (starting at 1st egg for each group)1 Eggs/bird (hen-day basis)
Mortality (No. of birds)* Growing treatment
1 2 3 4 5
Growing treatment
Laying Year
Growing Period
1
2
3
Total
8 4 6 13 14
28 29 34 23 22
32 41 32 28 30
39 36 41 39 43
107 110 113 103 109
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
*200 started per treatment.
TABLE 6.—Ejfect of feed restriction on three year egg production (starting at 20 wks) Eggs/bird (heri-day basis) Growing treatment
1st yr.
2nd yr.
2nd yr. Cum.
1 2 3 4 5
227 227 227 224 222
171 172 178 193 180
398 399 405 417 402
N.S.
N.S.
Full-fed Restr. 6-12 wks Restr. 6-18 wks Restr. 6-24 wks Restr. 12-24 wks
Analysis of Variance a b
3rd yr.
3rd yr. Cum.
113 a a b 128 a b 124b 137 116 a
511 527 529 554 518
P<.05
N.S.
- : Values not followed by the same letter are significantly different ( P < . 0 5 ) .
Full-fed 227° Restr. 6-12 wks 227" Restr. 6-18 wks 235ab 3 Restr. 6-24 wks 242 b Restr. 12-24 wks 3 239 b
Analysis of variance P < . 01
2nd yr.
2 yr. Cum.
3rd yr. 2
Cum.
171 172 177 189 175
398 399 412 431 414
104 a 118 a b 112 a b 123 b 104 a
502 517 524 554 518
N.S. (P-C.10) P < . 0 5 ( P < . 1 0 )
1
Laying year started as follows: 1—21 wks., 2—21 wks., 3—23 wks., 4—25 wks., 5—25 wks. These times represent the average age at which the first egg was laid in the replicate pens of the respective groups. 2 11 mo. only. 3 Significantly different from treatments 1 and 2 at the 5 % level of probability. Also 4 significantly different from 3. a b ' : Values in the same column not followed by the same letters are significantly different.
above basis it would have to be concluded that no reproductive advantage occurred from restricted feeding. The work of MacIntyre and Aitken (1959) emphasized the need for adjusting the production period to allow for the delay in sexual maturity of the restricted groups. In this experiment starting the reporting period for egg production while two of the groups were still undergoing their growing treatment placed a penalty of approximately 4 weeks on the latter groups. Therefore, in Table 7, egg production is shown with the production period for each group started at the approximate date of sexual maturity for that group. When figured in this way a highly significant difference in favor of the groups restricted to 24 weeks of age was found during the first laying year and a significant difference again in the third year for group 4 restricted from 6-24 weeks. Two and three year cumulative production approached statistical significance (P < .10). Since the experiment was terminated at the same time for all groups it was necessary to move the reporting period back 4 weeks in groups 1 and 2, and 2 weeks in group 3, thus providing a uniform 11 month period in the "3rd year" column. It is felt that providing each group with a laying period of uniform length is not only
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
restricted groups during the period of restriction. This difference among groups was completely overcome by the end of the first laying year so that mortality at that time, and thenceforth, was similar for all treatments. Egg Production. Restricting pullets from 6-24 weeks at the level of feed intake attained at 6 weeks proved to be advantageous in terms of egg production. When starting the production period at 20 weeks of age for all groups (Table 6), this advantage did not become statistically significant until the 3rd year, although the restricted groups overcame the 4-week head start of the full-fed group by the end of the 1st laying year. This is the first report to the author's knowledge of three years egg production data in a restricted feeding experiment. If this experiment had been concluded at the end of the first laying year as is usually done, or even at the end of the second year, and reported on the
1 2 3 4 5
1st yr.
RESTRICTED FEEDING
OF P U L L E T S
1311
21
22
23
21*
25 26 Weeks of Age
27
28
I?
Jo
FIG. 2. Egg production and egg size as affected by restricted feeding.
justifiable but preferable as long as both methods of calculation are shown. Egg Size and Quality. Rapid attainment of large egg size is one of the advantages claimed for restricted feeding and there is perhaps more agreement on this point than any other. Figure 2 illustrates this phenomenon where egg weight and egg production for the control group and the 6-24 week restricted group are plotted against the same time axis. The restricted birds required only 3 weeks and 44% production whereas the control group required 7 weeks and 74% production to attain an egg size of 53 grams. The restricted groups had not yet attained the body weight of the control group at this time. After this time egg weights remained quite uniform among treatments and weighing was discontinued after 16 months of production. Table 8 shows the similarity of numbers
and pounds of eggs produced to 72 weeks of age on the various treatments. Egg quality measurements (Table 9) included shell thickness and interior quality as measured by Haugh units on all eggs produced on 2 consecutive days after the birds had been in production approximately one year. No differences due to treatment were observed. Feed Consumption. Table 10 shows feed TABLE 8.-
-Weight of eggs produced in first year of production
Growing treatment 1 2 3 4 5
Full-fed Restr. 6-12 wks Restr. 6-18 wks Restr. 6-24 wks Restr. 12-24 wks
No. eggs Total wt. per bird of eggs/bird (H.D. basis) (lbs.) 227 227 227 224 222
31.9 32.1 31.5 31.8 31.2
* Using same starting date (20 wks of age) for alj treatment.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
Egg Production
1312
H. L. FULLER AND W. S. DUNAHOO
TABLE 9.—Shell thickness and Haugh units as a measure of egg quality after 1 year of production
Growing treatment
Shell Thickness (.001 inch)
Haugh units
Full-fed Restr. 6-12 wks Restr. 6-18 wks Restr. 6-24 wks Restr. 12-24 wks
15.59 15.30 15.60 15.60 15.70
69.3 65.8 70.4 69.5 69.4
1 2 3 4 5
TABLE 10.—Feed consumption and utilization as affected by restricted feeding Feed consumption (lbs./bird) Growing treatment
1. 2. 3. 4. 5.
Full fed Restr. 6-12 wk Restr. 6-18 wk Restr. 6-24 wk Restr. 12-24 wk
Feed conversion (Ibs./doz.)
Age at 1st egg (Wks)
6-24 wk
24-30
Day-old to first egg
21 21 23 25 25
17.1 17.0 15.9 12.9 13.3
11.7 11.5 11.6 11.2 11.9
15.0 14.8 16.3 16.5 16.9
"•*>: Values not followed by the same letter are significantly different (P<.05).
3 yr. prod. 6.31" 6.30» 6.05 s * 5.78 b 6.08*b
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
consumption for the entire growing period and feed conversion for the production period. Here again feed consumption is presented in 2 different ways. While there was an obvious difference in feed consumption to 24 weeks of age as a result of the restriction, the amount of feed required to grow the bird to sexual maturity, regardless of the age at maturity, was quite similar. Differences in feed conversion (lbs. of feed per dozen eggs) were highly significant and followed the same pattern as seen in egg production. While these differences may be attributed largely to differences in egg production, additional savings in feed may have resulted from the slightly smaller body weight of the 6-24 week restricted group. Practical Consideration. Obviously it is economically impractical to keep hens for 3 years for commercial egg production and in designing this experiment it was not anticipated that restricted feeding of pullets would alter greatly the practical economic life of the hens. This experiment
attempted to relate the effects of restricted feeding of growing chickens to findings in other species. To accomplish this it was necessary to observe egg production and mortality beyond the period that is normally observed when the duration of the experiment is limited by consideration of practical aspects only. When defining the laying year in the usual manner, based upon the same calendar dates, regardless of age at maturity, a significant difference in production was found only in the third laying year; although the severely restricted groups had overcome the delay in maturity, caused by the restriction, by the time they were 17 months old. Thus, these groups laid as many eggs in 11 months as the controls produced in 12 months. When charging the birds only for the time actually spent in the laying house (beginning at the approximate date of sexual maturity for each group) a highly significant increase in egg production was obtained during the first laying year as a result of restricted feeding from 6-24 weeks of age. Such a method of reporting is not impractical. Poultrymen can take advantage of this early "spurt" in egg production and egg size by properly planning their replacement schedule and simply extending the growing period by a few weeks. The extra time spent in the growing period was shown to require no more feed, so with little if any extra cost the poultryman
RESTRICTED FEEDING OF PULLETS
can utilize his laying houses to better advantage by reducing the long slow approach to peak production and egg size.
tive production approached statistical significance (P < .10) when calculated in this way. Treatment effect on egg size was evidenced only by larger initial eggs from pullets restricted to 24 weeks of age, with differences on any given calendar date not significant after the first few weeks. No statistical difference was found in amount of feed consumed by pullets to reach sexual maturity, but birds restricted more than 6 weeks required less feed per dozen eggs during the laying period. Mortality was higher in the severely restricted groups during the period of restriction and higher in the full-fed and less severely restricted groups during the early part of the laying period. Total mortality rates were not significantly different. No differences between experimental treatments were found in egg shell thickness or Haugh unit values of eggs when the birds had been in production for 12 months. REFERENCES Aron, H., 1911. Nutrition and growth, 1. Philippine J. Sci. 6 ( B ) : 1. Bruins, H. W., 1958. Energy restriction for replacement pullets. Feedstuffs, 30 (No. 39): 32-35. Duncan, D. G., 1955. Multiple range and multiple F tests. Biometrics, 11: 1-42. Fuller, H. L„ 1958. Restricted feeding of pullets for flock replacement. Proc. Nutr. Council, American Feed Mfrs. Assoc, Dec. 1-2, pp. 11-15. Fuller, H. L., 1962. Restricted feeding of pullets. 1. The value of pasture and self-selection of dietary components. Poultry Sci. (submitted for publication). Gowe, R. S., A. S. Johnson, R. D. Crawford, J. H. Downs, A. T. Hill, W. F. Mountain, J. R. Pelletin and J. H. Strain, 1960. Restricted versus full-feeding during the growing period for egg production stock. Brit. Poultry Sci. 1: 37-56. Hollands, K. G., and R. S. Gowe, 1961. The effect of restricted and full-feeding during confinement rearing on first and second year laying house performance. Poultry Sci. 40: 574-583.
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
SUMMARY White Leghorn pullets were subjected to restricted feed intake for the following periods: none, 6-12, 6-18, 6-24 and 12-24 weeks of age. During these periods feed was limited to the average intake at 6 weeks of age. Egg production characteristics were observed for 3 years. Growth was retarded significantly in all groups but in every case recovery was rapid after removal of restriction and curves of growth recovery were steeper than the normal curve at any point. Where restriction was removed by 12 weeks of age this rapid recovery carried this group to a greater weight than the controls at 24 weeks of age. Where restriction was continued from 6 to 24 weeks of age body weight remained slightly below the controls for the entire 3 years. Basal metabolic rate as measured by 0 2 consumption was lowered by restricted feeding and the lowered rate appeared to persist 6 months after removal of restriction. Feed restriction delayed sexual maturity from 0 to 4 weeks depending upon the duration of restriction, but the deficit in early egg production was overcome in less than 12 months. Restricting pullets from 6 to 24 weeks of age resulted in increased egg production which was statistically significant only during the third year when the production period was calculated from 20 weeks for all groups. When the production period for each treatment was adjusted according to the different maturity dates a highly significant difference in favor of the groups restricted to 24 weeks of age was found during the first laying year, and a significant difference again in the third year for the group restricted from 6-24 weeks of age. Two and three year cumula-
1313
1314
H.
L.
FULLER AND W.
Huston, T. M., T. E. Botton and J. L. Carmon, 1962. The influence of high environmental temperature on immature domestic fowl. Poultry Sci: (In press). Ingle, L., T. R. Wood and A. M. Banta, 1937. A study of longevity, growth, reproduction, and heart rate of Daphnia longispina as influenced by limitations in quantity of food. J. Exp. Zoo. 76: 325-352. Maclntyre, T. M., and J. R. Aitken, 1959. The performance of laying hens reared on restricted
S.
DUNAHOO
and full-feeding programs. Can. J. Animal Sci. 39: 217-225. Osborne, T. B., and L. B. Mendel, 1915. The resumption of growth after long continuous failure to grow. J. Biol. Chem. 23.: 439. Osborne, T. B., and L. B. Mendel, 1916. Acceleration of growth after retardation. Am. J. Physiol. 40: 16. Snedecor, G. W., 1956. Statistical Methods. Fifth Edition, Iowa State College Press, 534 pp.
B. H A L L DAVIS AND CLAYTON C.
Louisiana State University, Baton Rouge,
BRUNSON
Louisiana
(Received for publication January 12. 1962)
W
AYS of preventing the decline of interior egg quality have been studied extensively by many research workers. Oil as a spray or dip has gained wide acceptance. It has been used for long term storage for many years (Spamer, 1931), and has been the subject of much recent investigation. Sauter et al. (1960), studied oil as a spray, a dip and as an aerosol spray and reported that dipping produced the best results. Aerosol spray did not appear to aid in maintaining quality except for a slight reduction in weight loss. Oil as a spray compared favorably with oil as a dip in the reports of Schwall et al. (1961), Swanson et al. (1958), and Stadelman and Wilson (1958). A more recent method of preserving quality has been the use of cellophane as a carton overwrap. Some of the claims made for cellophane are, (1) it is moisture proof, thereby keeping moisture in the egg, (2) it is gas proof, therefore carbon dioxide stays inside the egg, (3) it is transparent and thus allows the consumer to view the contents of the package, and (4) it is attractive. Davis and Beeckler (1960) studied vari-
ous grades of cellophane, Cryovac, and polyethylene as an overwrap, as well as the various oil treatments in preventing quality decline. They found that oil submersion and Cryovac were very effective in preventing quality loss. Cellophane and polyethylene were less efficient in maintaining quality. These results agree in general with work reported by Fletcher et al. (1957), and Davis (1959). In this study the objectives were to test the effectiveness of oil and cellophane in, (1) preventing interior quality decline, (2) protecting against weight loss, and (3) preventing the absorption of odor at three temperature environments. MATERIALS AND METHODS A total of 672 eggs was used in the study. A 24-egg sample was broken to determine initial quality. The remaining eggs were divided into three lots of eighteen dozen each. Three treatments were used which were as follows: (1) eighteen dozen eggs were placed in 2 X 6 cartons with no shell or carton treatment, (2) eighteen dozen eggs were placed in 2 X 6 cartons which were overwrapped with a
Downloaded from http://ps.oxfordjournals.org/ at Michigan State University on April 1, 2015
Relative Effectiveness of Oil and Cellophane in Protecting Eggs