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Effect of Heat Drying Upon the Nutritive Value of Corn1
YOLK COLOR
nificantly, but increased as the level of xanthophyll oil was increased, was color index of the abdominal fat. Egg production was reduced on the average of 2.7 percent in the groups of pullets which received the added xanthophyll oil.
REFERENCES Almquist, J. H., 1933. Relationship of candled appearance of eggs to their quality. California Agr.
Exp. Sta. Bui. 561: 1-31. Botsford, H. E., 1940. Measuring egg quality inside the shell. University of Maryland Mimeograph Release, pp. 1-3. Haugh, R. R., 1937. The Haugh unit for measuring egg quality. U.S. Egg Poultry Mag. 43: 552-555 and 572-573. Hauver, W. E., Jr., and J. A. Hamann, 1956. Egg Grading Manual, Agriculture Handbook No. 75, U.S. Department of Agriculture, Washington, D.C. Heiman, V., and J. S. Carver, 1935. The yolk color index. U.S. Egg Poultry Mag. 8: 40-41. Henderson, E. W., and H. L. Wilcke, 1933. Effect of ration on yolk color. Poultry Sci. 4: 266-273. Parker, S. L., S. S. Gossman and W. A. Lippincott, 1926. Studies on egg quality. I. Variation in yolk color. Poultry Sci. 5 : 131-145. Snedecor, G. W., 1956. Statistical Methods. The Iowa State College Press, Ames, Iowa. Titus, H. W., J. C. Fritz and W. R. Kauffman, 1938. Some observations on egg-yolk color. Poultry Sci. 1: 38-45.
Effect of Heat Drying Upon the Nutritive Value of Corn 1 R. J. EMERICK, C. W. CARLSON AND H. L. WINTEEFELD South Dakota Agricultural Experiment Station, Brookings (Received for publication September 19, 1960)
H
ARVESTING high moisture corn and heat drying it to a suitable moisture content is frequently necessary or desirable. Initiation of this practice has been accompanied by questions concerning the effect of heat drying on the nutritive value of corn. Conflicting results have been reported. Clanton, Hemstrom and Matsushima (1960) fed corn dried at 190°F. to cattle and concluded that there was no effect on the digestibility of the various nutrients in rations containing heat dried corn. Jensen et al. (1960) observed no difference in weight gains or feed efficiencies of swine fed corn dried at temperatures from 140°F. to 1
Published with the approval of the Director of the South Dakota Agricultural Experiment Station as publication number 489 of the journal series.
220°F. Albert and Neumann (19SS) observed that 30 percent moisture corn dried at 180°F. to 16 percent moisture, when fed to cattle, appeared to be the same as similar corn that had been field dried to 16 percent moisture. Hathaway et al. (1952) on the other hand, found that the weight gains of rats fed diets containing corn dried at 80-2 40° F. were inversely correlated with the drying temperature of the corn. The corn was said to serve as a source of energy in one instance, and as a source of protein in another. However, abnormally low weight gains were obtained in all groups indicating an over-all suboptimal level of nutrition. The studies reported here were conducted to determine the effect of various drying
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 18, 2015
ACKNOWLEDGMENTS Appreciation is extended to Corn Products Sales Company, New York, New York, who graciously supplied the xanthophyll oil used in these studies, and to Dr. J. T. McCall, Animal Nutrition Department, University of Florida, Gainesville, for xanthophyll determinations.
991
992
R. J. EMEEICK, C. W. CARLSON AND H. L. WINTERFELD TABLE 1.—Composition of chick diets Ingredients
%
Ground Yellow Corn Soybean Oil Meal (50% Protein) Fish Meal (60% Protein) Alfalfa Meal (17% Protein) Dried Buttermilk Steamed Bone Meal Salt Mixture* Stabilized Yellow Grease Vitamins and Antibiotics! Methionine
50.45 35.0 2.0 2.0 2.0 3.0 0.5 0.5
t
0.05
temperatures upon the nutritive value of corn fed in complete diets to chicks (Trial 1) and rats (Trials 2 and 3) and to determine the extent of heat damage required to accomplish an alteration in the nutritive value of corn when fed under these conditions. EXPERIMENTAL Trial 1. Shelled corn, harvested in the fall of 1957 with an initial moisture conTABLE 2
—Proximate analysis of corn dried under various conditions Proximate analysis (Moisture-free basis)
Temp.
Time
(oF.) Trial 2* No Drying 70 100 150 200 250 Trial 3 70 150 200 250 350 450
(Hr.)
5
3i 2|
If 2i
H 2 0 after drying
Ether extract
/, fiber
Protein rroiein
Ash
Nitrogen free extract
C ade
(%)
(%)
(%)
(%)
(%)
(%)
17.06f 10.87 11.02 10.40 8.73 6.76
4.81 5.02 5.07 4.82 5.35 4.90
2.26 2.21 2.31 2.42 2.32 2.33
10.81 10.99 10.79 11.05 11.02 10.96
1.27 1.24 1.33 1.28 1.49 1.24
82.16 80.36 80.16 80.79 80.21 80.34
14.09J 12.19 12.54 9.04 10.51 4.91
4.41 4.54 4.53 4.62 4.68 4.73
2.34 2.41 2.32 2.45 2.35 2.88
10.59 10.57 10.68 10.68 10.72 10.76
1.62 1.82 1.63 1.73 1.63 1.73
81.04 80.66 80.83 80.52 80.62 79.90
* Corn from the same source was used in Trial 1 though handled separately. f Moisture content at the time rations were mixed. Original moisture content = 21%. j Original moisture content = 26.7%.
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 18, 2015
* Mixture of 39 lbs. iodized salt and 1 lb. of manganese sulphate. t Vitamins were added to supply each pound of ration with 1800 I.U. vitamin A; 625 I.C.U. vitamin D; 2 mg. riboflavin; 2 mg. calcium pantothenate;! 52 mg. choline; 12 mg. niacin; 4.5 meg. vitamin Bi 2 ; 10 I.U. vitamin E as alpha tocopherol; and 2 mg. procaine penicillin.
tent of 21 percent, was placed in shallow pans and dried in approximately 100 lb. lots under various conditions; i.e., left at room temperature (70°F.) for two days, or placed in a forced air oven and dried approximately seven hours at 100°F., four hours at 200°F., or two hours at 2S0°F. The resulting corn, containing 10-12 percent moisture was ground and incorporated into diets having the composition shown in Table 1 and fed ad libitum to chicks. Day-old male chicks of three types of breeding were used. Each of four treatment groups was composed of chicks representing replicated sub-groups of four sources of White Plymouth Rocks, three sources of Barred Plymouth Rocks and one source of Vantress X Arbor Acre crossbred chicks. The chicks were maintained in electrically heated brooders and individual weights were obtained biweekly during the fourweek experimental period. Trial 2. Corn used in Trial 2 was of the same origin as that used in Trial 1 but was handled separately in smaller volumes. One batch of corn remained undried and was stored frozen. The remainder was dried
993
DRYING AND NUTRITIVE VALUE OF CORN
TABLE 3.—Growth and feed utilization of chicks fed corn dried at various temperatures Drying tempera-
Average weiight at four weeks (gm.) Breed
70° 100° 200° 250°
W.P.R.* 345 359 343 342
B.P.R. t V.XA.A.J 458 318 322 429 463 317 442 312
Gm. feed/gm. weight gain 1.83 1.86 1.88 1.90
* Eight sub-groups of 3 male White Plymouth Rock chicks per group. t Six sub-groups of 5 male Barred Plymouth Rock chicks per group. X Two sub-groups of 13-15 male Vantress X Arbor Acre broiler type chicks per group.
TABLE 4.—Weight gains and feed efficiencies of rats fed heat dried corn Drying temperature
(°F.) Trial 2 No Drying 70 100 150 200 250 Trial 3 70 150 200 250 350 450
Av. feed Average weight consumption gain per gm. wt.gain (gm.)
(gm.)
125.6 132.1 130.0 129.8 132.1 122.3
2.76 2.72 2.66 2.79 2.54 2.94
181.3 189.6 183.0 195.3 194.0 151.5**
2.30 2.27 2.33 2.27 2.37 2.60
** Denotes significance at P = 0.01.
at temperatures in the range of 75-250°F. were free of visible heat damage. When dried at 350°F., however, 30 percent of the kernels showed varying degrees of damage. The damage ranged from a slight to moderate scorching. Drying at 450°F. for a longer period resulted in varying degrees of damage for 100 percent of the kernels. In this instance, 61 percent of the kernels were slightly to moderately scorched, 30 percent were severely scorched and 9 percent were severely burned. After drying, all batches were finely ground, placed in open pans and allowed to equilibrate to a constant moisture content which approximated 5.8 percent. Sprague-Dawley male rats were fed diets into which these various sources of corn were incorporated. The composition of the diets and the experimental conditions under which they were fed were as described for Trial 2. RESULTS AND DISCUSSION
The chemical composition of the corn used in Trials 2 and 3 is shown in Table 2. Only small differences were found, none of which appeared to be directly correlated with the drying temperatures. Similar data are not available for the corn used in Trial
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 18, 2015
under the conditions described for Trial 1 at temperatures of 70, 100, ISO, 200 and 250°F. An attempt was made to dry all lots of corn to 10-12 percent moisture. At the higher temperatures, however, overdrying occurred. Six groups, each consisting of nine Sprague-Dawley female rats, were fed diets into which the various batches of corn were incorporated. All diets consisted of the following: corn, 80.4 percent (based on 10 percent moisture content); casein, 14.0 percent; dried brewers yeast, 2.5 percent; salts XIV, 3.0 percent; vitamin B12 premix containing 27.5 meg. per gram, 0.1 percent. Fish liver oil was administered weekly. Feed consumption data were obtained for sub-groups of three rats each, and individual weights were obtained weekly during the four week experimental period. Trial 3. Corn used in Trial 3 was harvested in the fall of 1958 with an initial moisture content of 26.7 percent and subsequently dried as described for Trials 1 and 2. Drying temperatures of 70, 150, 200, 250, 350 and 450°F. were used. An attempt was made to dry all batches of corn to a moisture content of 10-12 percent with the exception that the corn dried at 450°F. was dried excessively in an attempt to obtain severe damage. The corn kernels dried
994
R. J. EMERICK, C. W.
CARLSON AND H. L. WINTERFELD
This difference is non-significant, however, and is inconsistent with the slight decrease in weight gain noted in Trial 2 when the diet contained corn dried at 250°F. These data fail to support the conclusion of Hathaway et al. (1952) that the energy value of corn is reduced by drying temperatures of 140°F. and greater. Their conclusion, however, was based on a correlation between the drying temperature of the corn and a growth depression which occurred when the corn was incorporated into rat diets apparently not adequate to support optimum growth. The data presented herein indicate that normal heat drying of corn at temperatures as high as 350°F. does not affect its nutritive value, presumably as a source of energy, when fed in complete diets. Further, severe burning, rather than mere scorching, appears to be required to effect such changes under the conditions outlined. SUMMARY
One source of high moisture corn dried at temperatures of 70-250°F. was incorporated into complete diets and fed to chicks (Trial 1) and rats (Trial 2 ) . Another source of high moisture corn was dried at temperatures of 70-450°F. and fed in similar diets to rats (Trial 3). Drying the corn at temperatures as high as 250°F. for chicks and 350°F. for rats caused no significant differences in weight gains or feed efficiencies despite a mild scorching of the grain which occurred at the higher temperature. When corn was severely burned at 450°F., a significant reduction in weight gain (16.4 percent) and a trend toward reduced feed efficiency (12.6 percent) occurred. REFERENCES Albert, W. W., and A. L. Neumann, 19SS. Study of the effect of high-temperature drying of highmoisture field shelled corn when fed to beef
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 18, 2015
1, though the original corn was the same as that used in Trial 2. Growth and feed efficiency data for the Trial 1 chicks are given in Table 3. The cross-bred broiler type chicks grew at a much faster rate than either type of the native Plymouth Rock chicks. An analysis of variance showed a highly significant weight gain difference between breeds. No significant effect of treatment was noted. Although the broiler-type chicks receiving the diet containing corn dried at 100°F. tended to grow somewhat slower than either of the adjacent groups, results with the other two types of chicks failed to indicate that any decrease in nutritive value of the corn had occurred as a result of treatment. Weight gain and feed efficiency data obtained from the use of rats in Trials 2 and 3 are shown in Table 4. In Trial 2 no significant differences were observed. There was, however, a trend toward lowered weight gain and feed efficiency when the diet contained corn dried at 250°F. In Trial 3 no significant differences occurred in the weight gains or feed efficiencies of rats fed diets containing corn dried at temperatures as high as 350°F. This lack of difference existed despite the visible damage inflicted upon 30 percent of the kernels dried at 350°F. as described earlier. When the corn was heated at 4S0°F. to the extent that 100 percent of the kernels showed visible damage, a significant lowering of weight gain and a trend toward reduced feed efficiency occurred. In this instance weight gain was 16.4 percent lower. and feed consumption per unit of weight gain was 12.6 percent higher than was obtained by use of the corn dried at 70°F. The reduction in weight gain is significant at the 1 percent level of probability. A trend toward increased weight gains occurred in Trial 3 when the diets contained corn dried at 2S0°F. and 350°F.
DRYING AND NUTRITIVE VALUE OF CORN steers. Univ. Illinois Cattle Feeders Day Report No. A5430h. Clanton, D. C , M. L. Hemstrom and J. Matsushima, 1960. Nutritive value of beet cattle rations containing artificially dried corn. J. Animal Sci. 19: 376-380. Hathaway, I. L., F. D. Yung and T. A. Kiesselbach,
995
1952. The effect of drying temperature upon the nutritive value and commercial grade of corn. J. Animal Sci. 11: 430-440. Jensen, A. H., S. W. Terrill and D. E. Becker, 1960. Nutritive value of corn dried at 140°, 180° and 220° Fahrenheit for swine of different ages. J. Animal Sci. 19:629-637.
J. A. MORRIS Division of Animal Genetics, C.S.I.R.O., Poultry Research Centre, Werribee, Victoria (Received for publication September 19, 1960)
INTRODUCTION than photoperiods. Their hens, for example, T IS well known that hens, kept under were subjected to outside noise and disnormal environmental conditions, have turbances and it could be that, even under a tendency to lay eggs mainly in the hours continuous light, the periods of activity of daylight. There are, however, exceptions (feeding etc.) were restricted to the normal to this and we have observed birds which daylight period. The observations recorded in this study could be regarded as notorious 'night layers.' One pullet for example, out of a total are a by-product of a selection programme of 14 eggs laid during the month of May in which selection of birds for breeding is in 1959, deposited seven between 8 p.m. based on the shortest mean interval of and 5 a.m., a period of complete darkness. time between successive eggs within cycles. Admittedly, such a pattern of lay is rare. The information obtained as a result of Warren and Scott (1936) showed that placing young pullets under continuous hens would lay at any hour of the day (24 light and continuous noise is considered hours) when placed under continuous arti- sufficiently interesting to merit placing on ficial lighting. Only a short period of time record. (less than seven days) was necessary for MATERIALS AND METHODS the disruption of the normal rhythm. McNally (1946) made similar observations One hundred and forty-four young pulbut Fraps, Neher and Rothchild (1947) lets of the White Leghorn 'M' Line were unable to induce their birds into a (selected previously for high Production state of random lay with the use of con- Index) were housed in single bird cages in tinuous light. In fact, their birds continued a sealed chamber at the onset of sexual mato lay as though they were on a normal turity. At the time of housing many of the diurnal-nocturnal rhythm corresponding to pullets had been in lay for a short period what would be expected on a 12-14 hour and the remainder were on the verge of lay. light day. Fraps, Neher and Rothchild The Chamber has been constructed in such (1947) suggested that the restriction of a way as to prevent the infiltration of outtime of oviposition observed by them must side light. It has inner walls and ceiling of have been regulated by some stimulus other two inch compressed straw and the dimen-
I
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The Effect of Continuous Light and Continuous Noise on Pullets Held in a Sealed Chamber
nificantly, but increased as the level of xanthophyll oil was increased, was color index of the abdominal fat. Egg production was reduced on the average of 2.7 percent in the groups of pullets which received the added xanthophyll oil.
REFERENCES Almquist, J. H., 1933. Relationship of candled appearance of eggs to their quality. California Agr.
Exp. Sta. Bui. 561: 1-31. Botsford, H. E., 1940. Measuring egg quality inside the shell. University of Maryland Mimeograph Release, pp. 1-3. Haugh, R. R., 1937. The Haugh unit for measuring egg quality. U.S. Egg Poultry Mag. 43: 552-555 and 572-573. Hauver, W. E., Jr., and J. A. Hamann, 1956. Egg Grading Manual, Agriculture Handbook No. 75, U.S. Department of Agriculture, Washington, D.C. Heiman, V., and J. S. Carver, 1935. The yolk color index. U.S. Egg Poultry Mag. 8: 40-41. Henderson, E. W., and H. L. Wilcke, 1933. Effect of ration on yolk color. Poultry Sci. 4: 266-273. Parker, S. L., S. S. Gossman and W. A. Lippincott, 1926. Studies on egg quality. I. Variation in yolk color. Poultry Sci. 5 : 131-145. Snedecor, G. W., 1956. Statistical Methods. The Iowa State College Press, Ames, Iowa. Titus, H. W., J. C. Fritz and W. R. Kauffman, 1938. Some observations on egg-yolk color. Poultry Sci. 1: 38-45.
Effect of Heat Drying Upon the Nutritive Value of Corn 1 R. J. EMERICK, C. W. CARLSON AND H. L. WINTEEFELD South Dakota Agricultural Experiment Station, Brookings (Received for publication September 19, 1960)
H
ARVESTING high moisture corn and heat drying it to a suitable moisture content is frequently necessary or desirable. Initiation of this practice has been accompanied by questions concerning the effect of heat drying on the nutritive value of corn. Conflicting results have been reported. Clanton, Hemstrom and Matsushima (1960) fed corn dried at 190°F. to cattle and concluded that there was no effect on the digestibility of the various nutrients in rations containing heat dried corn. Jensen et al. (1960) observed no difference in weight gains or feed efficiencies of swine fed corn dried at temperatures from 140°F. to 1
Published with the approval of the Director of the South Dakota Agricultural Experiment Station as publication number 489 of the journal series.
220°F. Albert and Neumann (19SS) observed that 30 percent moisture corn dried at 180°F. to 16 percent moisture, when fed to cattle, appeared to be the same as similar corn that had been field dried to 16 percent moisture. Hathaway et al. (1952) on the other hand, found that the weight gains of rats fed diets containing corn dried at 80-2 40° F. were inversely correlated with the drying temperature of the corn. The corn was said to serve as a source of energy in one instance, and as a source of protein in another. However, abnormally low weight gains were obtained in all groups indicating an over-all suboptimal level of nutrition. The studies reported here were conducted to determine the effect of various drying
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 18, 2015
ACKNOWLEDGMENTS Appreciation is extended to Corn Products Sales Company, New York, New York, who graciously supplied the xanthophyll oil used in these studies, and to Dr. J. T. McCall, Animal Nutrition Department, University of Florida, Gainesville, for xanthophyll determinations.
991
992
R. J. EMEEICK, C. W. CARLSON AND H. L. WINTERFELD TABLE 1.—Composition of chick diets Ingredients
%
Ground Yellow Corn Soybean Oil Meal (50% Protein) Fish Meal (60% Protein) Alfalfa Meal (17% Protein) Dried Buttermilk Steamed Bone Meal Salt Mixture* Stabilized Yellow Grease Vitamins and Antibiotics! Methionine
50.45 35.0 2.0 2.0 2.0 3.0 0.5 0.5
t
0.05
temperatures upon the nutritive value of corn fed in complete diets to chicks (Trial 1) and rats (Trials 2 and 3) and to determine the extent of heat damage required to accomplish an alteration in the nutritive value of corn when fed under these conditions. EXPERIMENTAL Trial 1. Shelled corn, harvested in the fall of 1957 with an initial moisture conTABLE 2
—Proximate analysis of corn dried under various conditions Proximate analysis (Moisture-free basis)
Temp.
Time
(oF.) Trial 2* No Drying 70 100 150 200 250 Trial 3 70 150 200 250 350 450
(Hr.)
5
3i 2|
If 2i
H 2 0 after drying
Ether extract
/, fiber
Protein rroiein
Ash
Nitrogen free extract
C ade
(%)
(%)
(%)
(%)
(%)
(%)
17.06f 10.87 11.02 10.40 8.73 6.76
4.81 5.02 5.07 4.82 5.35 4.90
2.26 2.21 2.31 2.42 2.32 2.33
10.81 10.99 10.79 11.05 11.02 10.96
1.27 1.24 1.33 1.28 1.49 1.24
82.16 80.36 80.16 80.79 80.21 80.34
14.09J 12.19 12.54 9.04 10.51 4.91
4.41 4.54 4.53 4.62 4.68 4.73
2.34 2.41 2.32 2.45 2.35 2.88
10.59 10.57 10.68 10.68 10.72 10.76
1.62 1.82 1.63 1.73 1.63 1.73
81.04 80.66 80.83 80.52 80.62 79.90
* Corn from the same source was used in Trial 1 though handled separately. f Moisture content at the time rations were mixed. Original moisture content = 21%. j Original moisture content = 26.7%.
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 18, 2015
* Mixture of 39 lbs. iodized salt and 1 lb. of manganese sulphate. t Vitamins were added to supply each pound of ration with 1800 I.U. vitamin A; 625 I.C.U. vitamin D; 2 mg. riboflavin; 2 mg. calcium pantothenate;! 52 mg. choline; 12 mg. niacin; 4.5 meg. vitamin Bi 2 ; 10 I.U. vitamin E as alpha tocopherol; and 2 mg. procaine penicillin.
tent of 21 percent, was placed in shallow pans and dried in approximately 100 lb. lots under various conditions; i.e., left at room temperature (70°F.) for two days, or placed in a forced air oven and dried approximately seven hours at 100°F., four hours at 200°F., or two hours at 2S0°F. The resulting corn, containing 10-12 percent moisture was ground and incorporated into diets having the composition shown in Table 1 and fed ad libitum to chicks. Day-old male chicks of three types of breeding were used. Each of four treatment groups was composed of chicks representing replicated sub-groups of four sources of White Plymouth Rocks, three sources of Barred Plymouth Rocks and one source of Vantress X Arbor Acre crossbred chicks. The chicks were maintained in electrically heated brooders and individual weights were obtained biweekly during the fourweek experimental period. Trial 2. Corn used in Trial 2 was of the same origin as that used in Trial 1 but was handled separately in smaller volumes. One batch of corn remained undried and was stored frozen. The remainder was dried
993
DRYING AND NUTRITIVE VALUE OF CORN
TABLE 3.—Growth and feed utilization of chicks fed corn dried at various temperatures Drying tempera-
Average weiight at four weeks (gm.) Breed
70° 100° 200° 250°
W.P.R.* 345 359 343 342
B.P.R. t V.XA.A.J 458 318 322 429 463 317 442 312
Gm. feed/gm. weight gain 1.83 1.86 1.88 1.90
* Eight sub-groups of 3 male White Plymouth Rock chicks per group. t Six sub-groups of 5 male Barred Plymouth Rock chicks per group. X Two sub-groups of 13-15 male Vantress X Arbor Acre broiler type chicks per group.
TABLE 4.—Weight gains and feed efficiencies of rats fed heat dried corn Drying temperature
(°F.) Trial 2 No Drying 70 100 150 200 250 Trial 3 70 150 200 250 350 450
Av. feed Average weight consumption gain per gm. wt.gain (gm.)
(gm.)
125.6 132.1 130.0 129.8 132.1 122.3
2.76 2.72 2.66 2.79 2.54 2.94
181.3 189.6 183.0 195.3 194.0 151.5**
2.30 2.27 2.33 2.27 2.37 2.60
** Denotes significance at P = 0.01.
at temperatures in the range of 75-250°F. were free of visible heat damage. When dried at 350°F., however, 30 percent of the kernels showed varying degrees of damage. The damage ranged from a slight to moderate scorching. Drying at 450°F. for a longer period resulted in varying degrees of damage for 100 percent of the kernels. In this instance, 61 percent of the kernels were slightly to moderately scorched, 30 percent were severely scorched and 9 percent were severely burned. After drying, all batches were finely ground, placed in open pans and allowed to equilibrate to a constant moisture content which approximated 5.8 percent. Sprague-Dawley male rats were fed diets into which these various sources of corn were incorporated. The composition of the diets and the experimental conditions under which they were fed were as described for Trial 2. RESULTS AND DISCUSSION
The chemical composition of the corn used in Trials 2 and 3 is shown in Table 2. Only small differences were found, none of which appeared to be directly correlated with the drying temperatures. Similar data are not available for the corn used in Trial
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 18, 2015
under the conditions described for Trial 1 at temperatures of 70, 100, ISO, 200 and 250°F. An attempt was made to dry all lots of corn to 10-12 percent moisture. At the higher temperatures, however, overdrying occurred. Six groups, each consisting of nine Sprague-Dawley female rats, were fed diets into which the various batches of corn were incorporated. All diets consisted of the following: corn, 80.4 percent (based on 10 percent moisture content); casein, 14.0 percent; dried brewers yeast, 2.5 percent; salts XIV, 3.0 percent; vitamin B12 premix containing 27.5 meg. per gram, 0.1 percent. Fish liver oil was administered weekly. Feed consumption data were obtained for sub-groups of three rats each, and individual weights were obtained weekly during the four week experimental period. Trial 3. Corn used in Trial 3 was harvested in the fall of 1958 with an initial moisture content of 26.7 percent and subsequently dried as described for Trials 1 and 2. Drying temperatures of 70, 150, 200, 250, 350 and 450°F. were used. An attempt was made to dry all batches of corn to a moisture content of 10-12 percent with the exception that the corn dried at 450°F. was dried excessively in an attempt to obtain severe damage. The corn kernels dried
994
R. J. EMERICK, C. W.
CARLSON AND H. L. WINTERFELD
This difference is non-significant, however, and is inconsistent with the slight decrease in weight gain noted in Trial 2 when the diet contained corn dried at 250°F. These data fail to support the conclusion of Hathaway et al. (1952) that the energy value of corn is reduced by drying temperatures of 140°F. and greater. Their conclusion, however, was based on a correlation between the drying temperature of the corn and a growth depression which occurred when the corn was incorporated into rat diets apparently not adequate to support optimum growth. The data presented herein indicate that normal heat drying of corn at temperatures as high as 350°F. does not affect its nutritive value, presumably as a source of energy, when fed in complete diets. Further, severe burning, rather than mere scorching, appears to be required to effect such changes under the conditions outlined. SUMMARY
One source of high moisture corn dried at temperatures of 70-250°F. was incorporated into complete diets and fed to chicks (Trial 1) and rats (Trial 2 ) . Another source of high moisture corn was dried at temperatures of 70-450°F. and fed in similar diets to rats (Trial 3). Drying the corn at temperatures as high as 250°F. for chicks and 350°F. for rats caused no significant differences in weight gains or feed efficiencies despite a mild scorching of the grain which occurred at the higher temperature. When corn was severely burned at 450°F., a significant reduction in weight gain (16.4 percent) and a trend toward reduced feed efficiency (12.6 percent) occurred. REFERENCES Albert, W. W., and A. L. Neumann, 19SS. Study of the effect of high-temperature drying of highmoisture field shelled corn when fed to beef
Downloaded from http://ps.oxfordjournals.org/ at Mount Allison University on June 18, 2015
1, though the original corn was the same as that used in Trial 2. Growth and feed efficiency data for the Trial 1 chicks are given in Table 3. The cross-bred broiler type chicks grew at a much faster rate than either type of the native Plymouth Rock chicks. An analysis of variance showed a highly significant weight gain difference between breeds. No significant effect of treatment was noted. Although the broiler-type chicks receiving the diet containing corn dried at 100°F. tended to grow somewhat slower than either of the adjacent groups, results with the other two types of chicks failed to indicate that any decrease in nutritive value of the corn had occurred as a result of treatment. Weight gain and feed efficiency data obtained from the use of rats in Trials 2 and 3 are shown in Table 4. In Trial 2 no significant differences were observed. There was, however, a trend toward lowered weight gain and feed efficiency when the diet contained corn dried at 250°F. In Trial 3 no significant differences occurred in the weight gains or feed efficiencies of rats fed diets containing corn dried at temperatures as high as 350°F. This lack of difference existed despite the visible damage inflicted upon 30 percent of the kernels dried at 350°F. as described earlier. When the corn was heated at 4S0°F. to the extent that 100 percent of the kernels showed visible damage, a significant lowering of weight gain and a trend toward reduced feed efficiency occurred. In this instance weight gain was 16.4 percent lower. and feed consumption per unit of weight gain was 12.6 percent higher than was obtained by use of the corn dried at 70°F. The reduction in weight gain is significant at the 1 percent level of probability. A trend toward increased weight gains occurred in Trial 3 when the diets contained corn dried at 2S0°F. and 350°F.
DRYING AND NUTRITIVE VALUE OF CORN steers. Univ. Illinois Cattle Feeders Day Report No. A5430h. Clanton, D. C , M. L. Hemstrom and J. Matsushima, 1960. Nutritive value of beet cattle rations containing artificially dried corn. J. Animal Sci. 19: 376-380. Hathaway, I. L., F. D. Yung and T. A. Kiesselbach,
995
1952. The effect of drying temperature upon the nutritive value and commercial grade of corn. J. Animal Sci. 11: 430-440. Jensen, A. H., S. W. Terrill and D. E. Becker, 1960. Nutritive value of corn dried at 140°, 180° and 220° Fahrenheit for swine of different ages. J. Animal Sci. 19:629-637.
J. A. MORRIS Division of Animal Genetics, C.S.I.R.O., Poultry Research Centre, Werribee, Victoria (Received for publication September 19, 1960)
INTRODUCTION than photoperiods. Their hens, for example, T IS well known that hens, kept under were subjected to outside noise and disnormal environmental conditions, have turbances and it could be that, even under a tendency to lay eggs mainly in the hours continuous light, the periods of activity of daylight. There are, however, exceptions (feeding etc.) were restricted to the normal to this and we have observed birds which daylight period. The observations recorded in this study could be regarded as notorious 'night layers.' One pullet for example, out of a total are a by-product of a selection programme of 14 eggs laid during the month of May in which selection of birds for breeding is in 1959, deposited seven between 8 p.m. based on the shortest mean interval of and 5 a.m., a period of complete darkness. time between successive eggs within cycles. Admittedly, such a pattern of lay is rare. The information obtained as a result of Warren and Scott (1936) showed that placing young pullets under continuous hens would lay at any hour of the day (24 light and continuous noise is considered hours) when placed under continuous arti- sufficiently interesting to merit placing on ficial lighting. Only a short period of time record. (less than seven days) was necessary for MATERIALS AND METHODS the disruption of the normal rhythm. McNally (1946) made similar observations One hundred and forty-four young pulbut Fraps, Neher and Rothchild (1947) lets of the White Leghorn 'M' Line were unable to induce their birds into a (selected previously for high Production state of random lay with the use of con- Index) were housed in single bird cages in tinuous light. In fact, their birds continued a sealed chamber at the onset of sexual mato lay as though they were on a normal turity. At the time of housing many of the diurnal-nocturnal rhythm corresponding to pullets had been in lay for a short period what would be expected on a 12-14 hour and the remainder were on the verge of lay. light day. Fraps, Neher and Rothchild The Chamber has been constructed in such (1947) suggested that the restriction of a way as to prevent the infiltration of outtime of oviposition observed by them must side light. It has inner walls and ceiling of have been regulated by some stimulus other two inch compressed straw and the dimen-
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The Effect of Continuous Light and Continuous Noise on Pullets Held in a Sealed Chamber