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An Estimate of the Threonine Requirement of the Laying Hen*
1362
F. H. WILCOX
REFERENCES Bogdonoff, P. D., Jr., and C. S. Shaffner, 1954. The effect of pH on in vitro survival, metabolic activity, and fertilizing capacity of chicken semen. Poultry Sci. 33:665-669. Bonnier, G., and S. Trulsson, 1939. Artificial insemination of chickens with semen diluted in Ringer solution. Proc. World's Poultry Congr.,
7th Congr., Cleveland: 76-79. Gilbreath, J. C , and G. T. Davis, 1949. A fertility study with turkeys using different concentrations of semen. Poultry Sci. 28: 406-^10. Gordon, R. F., and J. G. Phillips, 1951. Poultry production and progeny trials. Report of the results of the artificial insemination carried out from March to April, 1951. Poultry Progress, 1: 1-7. Munro, S. S., 1938. The effect of dilution and density on the fertilizing capacity of fowl sperm suspensions. Can. J. Research, 16, D : 281-299. Parker, J. E., F. F. McKenzie and H. L. Kempster, 1942. Fertility in the male domestic fowl. Missouri Agr. Exp. Sta. Res. Bui. 347: 1-50. Rowell, J. G., and D. M. Cooper, 1957. The relation between fertility in the fowl and the dilution rate of the semen using a glycine diluent. Poultry Sci. 36: 706-712. Van Tienhoven, A., and R. G. D. Steel, 1957. The effect of different diluents and dilution rates on fertilizing capacity of turkey semen. Poultry Sci. 36: 473-479. Weakley, C. E., I l l , and C. S. Shaffner, 1952. The fertilizing capacity of diluted chicken semen. Poultry Sci. 31:650-653.
An Estimate of the Threonine Requirement of the Laying Hen* J. S. ADKINS, E. C. MILLEB, H. R. BIRD, C. A. ELVEHJEM AND M. L. SUNDE Departments of Poultry Husbandry and Biochemistry, University of Wisconsin, Madison 6, Wisconsin (Received for publication April 7, 1958)
I
N FEEDING laying hens purified diets that contain all amino acid nitrogen in place of intact protein, the largest expense is for the essential amino acid, threonine. While the level of threonine required by the chick (0.60 percent; Alm-• quist, 1947) is known, the requirement of: the laying hen is not established. In all[ Published with the approval of the Director ofi the Wisconsin Agricultural Experiment Station,, College of Agriculture, Madison, Wisconsin. * Supported in part by the Research Committee\ of the Graduate School from funds supplied by the Wisconsin Alumni Research Foundation, Madison, Wisconsin.
cases where the amino acid requirement has been established for the laying hen (isoleucine, Miller et al., 1954; leucine, Machlin, 1955; lysine and tryptophan, Ingram et al. 1951a; methionine, Ingram et al., 1951b, Leong and McGinnis, 1951), it was found to be less than the chick requirement. If the threonine requirement of the laying hen could be established, it could result in a considerable reduction in the expense of feeding purified diets containing alpha amino acids. The possibility of an imbalance or toxicity developing from too much threonine must also be considered. In the following three experi-
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 30, 2015
tion of fertility, which was more pronounced the second week after insemination than the first. There was little change in fertility when the seminal plasma was replaced by the buffer following centrifugation. A two-fold concentration of semen resulted in a slight improvement of fertility when compared with the seminal plasma replaced with an equal quantity of buffer. Fertility was not improved when the amount of diluted semen (1 to 10 or 1 to 20) inseminated was increased from 0.1 to 0.2 ml. Hatchability was unaffected by dilution.
1363
THREONINE REQUIREMENT OF THE LAYING H E N
ments designed to ascertain the threonine requirement of the laying hen, various levels of threonine were added to diets containing seven or eight percent crude casein. The remaining protein was supplied by crystalline amino acids. EXPERIMENTAL
All of the amino acid requirements of the laying hen established to date were accomplished by using crude protein which was deficient in one of the essential amino acids. Since all proteins contain adequate threonine to meet the requirement of the chicken when incorporated into the diet at the recommended protein level, this method could not be used to establish the threonine requirement. A Wisconsin practical all mash ration for laying hens producing market eggs, analyzing 16.0 percent protein, contains 0.87 percent L-threonine, (calculation based on values of Lyman et al., 1956). This figure represents 1.45 times the threonine requirement of the chick. In order to formulate a diet that was low in threonine, it was necessary to use a lower level of intact protein in the diet than is
7 percent 8 percent 17 percent casein casein casein
%
L-arginine HC1 0.60 L-tyrosine 0.70 DL-phenylalanine 0.60 DL-tryptophan 0.20 DL-methionine 0.50 DL-leucine 0.40 DL-isoleucine (44 percent L) 0.40 DL-valine 0.60 L-glutamic acid 4.00 Glycine 1.00 Crude casein 7.00 Alphacel 5.00 Feeding oil (1,S00A-300D) 0.50 Salts V* 6.00 Alpha tocopherol (0.6 mg./gm.) 0.50 Choline chloride (70 percent) 0.10 Soybean oil 3.00 Vitamin mixf 0.50 Antiacid Dextrin 68.40 Calculated Productive Energy (Calories/pound) 925 Protein percent (by analysis) 12.5
—.
%
0.60 0.70 0.60 0.20 0.50 0.40 0.40 0.60 4.00 1.00 8.00 5.00 0.50 6.00 0.50 0.10 9.50 0.50 1.00 59.90 1030 13.4
%
0.34
— — — — — — — 0.50 0.10
17.00
—
0.50 6.00 0.50 0.10 2.50 0.50
— .
71.96 1051 16.4
* Briggs el al. (1943). f Vitamin mix supplies the following vitamins in milligrams per kilogram of diet: thiamine HC1 6; biotin 0.2; pyridoxine HC1 4; menadione 0.5_; folic acid 4.0; riboflavin 6.0; calcium pantothenate 20.0; niacin 50.0; inositol 1,000.0; and vitamin B12 0.03.
recommended by the National Research Council Publication 301 (Bird et al., 1954) and supplement the diet with the essential amino acids to meet the requirements of the hen. The composition of the diets used in the following experiments is given in Table 1. The diets contained seven or eight percent crude casein which supplied 0.27 or 0.32 percent L-threonine. The threonine content of the diet was determined by the microbiological assay method of Henderson and Snell (1948) using 5. fecalis as the test organism. The amino acids added to the diet supplied 6.03 percent of equivalent protein (calculated from the nitrogen contained in the amino acids X 6.25). Kjeldahl analysis of this diet showed it to contain 12.5 percent equivalent protein (N X 6.25). Previous experiments show that this level of protein in the diet is adequate for good egg production (Miller et al., 1957) and (Thornton el al., 1957). The level of threonine required would probably vary slightly from that found in this experiment if a 15 percent protein diet were fed.
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 30, 2015
Groups of two Single Comb White Leghorn pullets were kept in laying batteries with raised wire floors. Feed, water and oyster shells were supplied ad libitum. The pullets were placed on a purified diet containing 17 percent casein to accustom them to this type of diet before they were placed on the experimental diets. Only pullets with rates of egg production over 60 percent were selected for the experiments. The pullets were artificially inseminated weekly with pooled semen from New Hampshire males. The eggs were collected daily and pedigree hatched. At the time of setting, all eggs were weighed individually. All eggs which failed to hatch were broken out to determine the age of the embryos at death.
TABLE 1.—Composition of basal diets
1364
J. S. ADKINS, E. C. MILLER, H. R. BIRD, C. A. ELVEHJEM AND M. L. SUNDE
RESULTS AND DISCUSSION Egg Production. Table 2 shows that better egg production was obtained when the diet contained 0.42 percent L-threonine or higher levels than when it contained lower levels of threonine in two out of the three experiments. In the first experiment, birds fed 0.47 percent L-threonine or a higher level exceeded the egg
TABLE 2.—Effect of dietary threonine levels on egg production* Percent Experi- Experi- ExperiAve of 3 L-threoment 1 ment 2 ment 3 experinine in (9 weeks) (7 weeks) (7 weeks) ments the diet 0.27 0.32 0.37 0.42 0.47 0.52 0.57 0.62 17 percent casein control (0.66)
28.5 33.0 28.0 24.5f 47.5
%
%
%
45.5 50.0 43.0
27.5 25.5 45.8 49.0 76.2
53.0
33.5
56.0
23.5
57.5
%
51.7*
26.0 30.2 33.0 40.1 46.5 76.2 43.2 51.7
64.2
59.2
* 2 birds per group in all experiments. f 1 bird died during 4th week of experiment. j 1 bird died during 3rd week of experiment.
production of birds receiving lower levels of threonine. Egg production of hens receiving 0.27, 0.32 or 0.37 percent L-threonine averaged 29.8 percent production for the three experiments while those fed higher levels had a weighted average of 47.4 percent production for the seven or nine week experimental period. The highest production was obtained in experiment 3. The group of only two birds receiving 0.52 percent L-threonine averaged 76.2 percent production. If this group is excluded, the remainder of the pullets receiving more than 0.37 percent L-threonine averaged 45.4 percent production. The poorest production for any experiment was obtained on the basal diet in experiment 2. This group receiving 0.27 percent L-threonine averaged 23.5 percent production. The control birds, fed a 17 percent casein diet, averaged 59.2 percent production during the period. Body Weight Maintenance. Apparently the type of diet fed imposed a stress on the birds, since in most cases a loss in body weight occurred during the experimental period regardless of the level of threonine supplementation, (Table 3). The greatest
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 30, 2015
The diets contained 925 or 1,030 Calories of productive energy per pound (calculated from the values of Titus, 1955). The dextrin productive energy value used was 1,100 Calories per pound. DL-threonine (alio free) was used to supplement the diets. It has been shown by Grau (1949) that DL-threonine is only one-half as active as the L-isomer for chicks. In supplementing with DL-threonine in the experiments reported here, it was assumed that the D-isomer of threonine was not utilized by the laying hen. The crystalline amino acids added in the diets were premixed to insure uniformity. Each amino acid was weighed and placed in a mortar and then several amino acids were ground together. After grinding in the mortar, the amino acids were placed in a large plastic bag and mixed thoroughly and then reground in the mortar to assure complete uniformity of the amino acid premix. In the last experiment one percent of an antiacid mixture (one part aluminum hydroxide to three parts magnesium trisilicate) was added to the diet. It was reported (Fisher et al., 1956) that an antiacid adsorbent, originally introduced in diets to prevent development of bleeding ulcers also helped to prevent early stoppage of feed consumption and egg production of hens fed an amino acid diet. Graded levels of threonine were added to the basal diet to determine the minimum level required for egg production and body weight maintenance.
1365
THREONINE REQUIREMENT OF THE LAYING H E N TABLE 3.—Effect
of various levels of threonine in the diet on body weight maintenance Casein control
Total percent L-threonine Average change in weight (gms.)
0.27 -412
0.32 -160
0.37 -162
0.42* -65
0.47 -67
0.52 -92
0.57 -56
0.62f -108
0.66 +3
• 1 bird died 4th week of experiment, f 1 bird died 3rd week of experiment.
TABLE 4.—Effect
GRAMS
2100
_
FIG. 1. Effect of threonine on body weight maintenance. Basal diets Al and A2 contained 0.27 and 0.32% L threonine respectively. Diet A3, 0.42% L threonine; A4, 0.57% L threonine; A5, 0.66% L threonine (17% Casein Control).
higher levels was better than that of hens on diets containing lower levels of threonine. Egg Size and Hatchability. Table 5 contains a summary of egg weights. The level
of various levels of threonine in the diet on feed consumption and utilization Casein control
Total percent L-threonine Grams of feed per bird/wk. Grams of feed per egg
0.27 491 256
* 1 bird died 4th week of experiment, f 1 bird died 3rd week of experiment.
0.32 450 233
0.37 509 209
0.42* 623 157
0.47 558 161
0.52 699 130
0.57 575 208
0.62f 600 149
0.66 825 154
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loss in body weight occurred in the groups receiving the basal diets. Hens fed the basal diet (0.27 percent L-threonine) lost an average of 412 grams. When the diet contained 0.32 or 0.37 percent L-threonine, the losses in body weight were not as great (160 and 162 grams respectively). Hens fed 0.42 percent L-threonine or higher levels lost an average of 77.6 grams. The control birds gained an average of three grams. Figure 1 shows that the birds require a depletion period of about five weeks or longer before maximum loss of body weight is noted. Feed Consumption and Utilization. Table 4 contains a summary of measurements of feed consumption. Feed consumption ranged from 450 to 825 grams of feed per bird per week. The levels of threonine supplementation had an inconsistent effect on the feed consumption. There was a trend toward higher consumption of birds fed higher levels of threonine. The hens fed the basal diets consumed less feed than other groups. Feed utilization of the hens on diets supplying 0.42 percent L-threonine or
1366
J. S. ADKINS, E. C. MILLER, H. R. BIRD, C. A. ELVEHJEM AND M. L. SUNDE
TABLE 5.—Effect of various levels of threonine in the diet on egg size Average egg weights (gms.) Percent of L-threonine • in diet
Week 1
2
0.27 55.8 49.0 0.32 52.2 46.5 0.37 50.2 51.1 0.42 54.9 51.8 0.47 55.9 53.5 0.57 54.3 53.6 0.62 52.9 52.7 Casein control (0.66) 55.9 55.4
3
4
5
6
7
52.0 52.0 49.5 51.6 50.4 52.1 54.5
51.0 49.5 51.0 54.2 54.0 53.7 54.6
47.0 42.1 49.0 53.5 54.7 54.3 55.4
48.0 49.7 48.3 52.3 51.7 53.1 54.5
56.0* 51.0 51.0 52.8 53.9 54.0 54.0
52.7
55.7
55.5
54.4
56.1
nine requirement of the laying hen has been made using crude casein supplemented with crystalline amino acids as the sources of protein in the ration. When egg production, feed consumption, body weight maintenance and egg size are considered, it appears that the L-threonine requirement of the laying hen approximates 0.42 percent of the diet. REFERENCES
of threonine used in the diets for this experiment had an inconsistent effect on egg size. There was a trend toward small eggs from birds fed the lower levels of threonine (0.27, 0.32 and 0.37). Birds fed 0.42 percent L-threonine or higher maintained a fairly constant egg size throughout the experimental period. The greatest variation was noted from hens fed the basal diet containing 0.32 percent threonine. The egg size decreased from an average of 52.2 grams at the beginning of the experiment to an average of 42.1 grams by the fifth week of the experiment. Apparently a depletion period is required before a dietary effect can be noted on the egg size of a hen. The level of threonine supplementation did not have any effect on hatchability as hatchability was excellent for all groups throughout all experiments. Since the laying hen requires 15 percent protein (Bird et al., 1954) in the diet as compared to 20 percent required by the chick, 75 percent of the threonine requirement of the chick (0.6 percent Lthreonine) should be adequate to meet the requirement of the laying hen (0.45 percent L-threonine). It is of interest to note that levels below 0.42 percent were inferior to higher levels. SUMMARY
A quantitative estimation of the threo-
Almquist, H. J., 1947. Evaluation of the amino acid requirement by observation on the chick. J. Nutrition, 34: 543-564. Bird, H. R., H. J. Almquist, W. W. Cravens, F. W, Hill and J. McGinnis, 1954. Nutrient requirements for domestic animals No. 1. Nutrient requirements for poultry. National Research Council Publication No. 301, Washington 25, D. C. Briggs, G. M., Jr., T. G. Luckey, C. A. Elvehjem and E. B. Hart, 1943. Study on two chemically unidentified water soluble vitamins necessary for the chick. J. Biol. Chem. 148: 163-172. Fisher, H., and D. Johnson, Jr., 1956. The amino acid requirement of the laying hen. J. Nutrition, 60: 261-273. Grau, C. R., 1949. The threonine requirement of the chick. J. Nutrition, 37: 105. Henderson, L. M., and E. E. Snell, 1948. A uniform medium for determination of amino acids with various microorganisms. J. Biol. Chem. 172: 15-30. Ingram, G. R., W. W. Cravens, C. A. Elvehjem and J. G. Halpin, 1951a. Studies on lysine and tryptophan requirements of the laying hen. Poultry Sci. 30: 426-430. Ingram, G. R., W. W. Cravens, C. A. Elvehjem and J. G. Halpin, 1951b. The methionine requirement of the laying hen. Poultry Sci. 30: 431^134. Leong, K. C , and J. McGinnis, 1951. An estimate of the methionine requirement for egg production. Poultry Sci. 31: 692-699. Lyman, C. M., K. A. Kuiken and F. Hale, 1956. Essential amino acid content of farm feeds. Agr. Food Chem. 4: 1008-1013. Machlin, L. J., 1955. An estimate of the leucine requirement of the laying hen. Poultry Sci. 34: 984-985. Miller, E. C , M. L. Sunde, H. R. Bird and C. A. Elvehjem, 1954. The isoleucine requirement of the laying hen. Poultry Sci. 33: 1201-1209.
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 30, 2015
* 1 egg only.
THREONINE REQUIREMENT OF THE LAYING H E N Miller, E. C , M. L. Sunde and C. A. Elvehjem, 1957. Minimum protein requirement of laying pullets at different energy levels. Poultry Sci. 36: 681-690. Thornton, P. A., L. G. Blaylock and R. E. Moreng,
1367
1957. The protein level as a factor in egg production. Poultry Sci. 36: 552-557. Titus, H. W., 1955. Scientific Feeding of Chickens, 2nd edition. Interstate Printers and Publishers, 19-27 North Jackson Street, Danville, Illinois.
C . W . WOODMANSEE2 AND 0 . J . ABBOTT 3 Delaware Agricultural Experiment Station, Newark, Delaware (Received for publication April 7, 1958)
T
HE temperature which is used commonly for scalding in the commercial processing of poultry is about 128°F., generally referred to as semi-scalding. Within the last few years there has been a trend toward increasing the temperature to about 140°F., commonly known as sub-scalding, for certain types of poultry products. This higher temperature of scald facilitates the removal of feathers, especially the pin-feathers, thereby reducing substantially the labor required for this operation according to Gwin (1950, 1951, 1952). The relative merits of subscalding versus semi-scalding have been discussed by Line weaver and Klose (1952). In comparison to semi-scalded birds which retain a normal skin appearance, sub-scalded broilers have an altered skin appearance because the rubber fingers of the mechanical pickers remove part or the whole of the outer epidermal portion of the skin. This altered skin surface is more susceptible to dehydration and darkening during processing, storage, and mar1
Published as Miscellaneous Paper No. 301 with the approval of the Director of the Delaware Agricultural Experiment Station. 2 Department of Agricultural Chemistry. 8 Department of Animal and Poultry Industry.
keting as shown by observations such as those of Klose and Pool (1954) and Pool, Mecchi, Lineweaver and Klose (1954). Ziegler and Stadelman (1955) found that the shelf-life of sub-scalded birds was shorter than that of semi-scalded birds when stored at refrigerator temperature in polyethylene bags as indicated by an earlier development of off-odor and slime. Tests made by Graf and Stewart (1953) for the Quartermaster Food and Container Institute of the Armed Forces recommend the sub-scald treatment provided the broilers are not air chilled or the skin permitted to become dry. Although the sub-scalding process reduces hand pinning substantially in the processing industry, its use has been confined primarily to the dressing of birds for the quick-frozen trade (Gwin, 1951). It occurred to the authors that the application of a moisture resistant coating following the sub-scald treatment would afford protection against dehydration and darkening similar to that provided by the natural skin coating retained in the semiscald treatment. A report in the Chemical and Engineering News (1955) suggested the potential use of acetoglycerides as an edible, skin-tight coating on meats al-
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 30, 2015
Coating Sub-Scalded Broiler Parts in Order to Afford Protection against Dehydration and Skin Darkening in Fresh Storage1
F. H. WILCOX
REFERENCES Bogdonoff, P. D., Jr., and C. S. Shaffner, 1954. The effect of pH on in vitro survival, metabolic activity, and fertilizing capacity of chicken semen. Poultry Sci. 33:665-669. Bonnier, G., and S. Trulsson, 1939. Artificial insemination of chickens with semen diluted in Ringer solution. Proc. World's Poultry Congr.,
7th Congr., Cleveland: 76-79. Gilbreath, J. C , and G. T. Davis, 1949. A fertility study with turkeys using different concentrations of semen. Poultry Sci. 28: 406-^10. Gordon, R. F., and J. G. Phillips, 1951. Poultry production and progeny trials. Report of the results of the artificial insemination carried out from March to April, 1951. Poultry Progress, 1: 1-7. Munro, S. S., 1938. The effect of dilution and density on the fertilizing capacity of fowl sperm suspensions. Can. J. Research, 16, D : 281-299. Parker, J. E., F. F. McKenzie and H. L. Kempster, 1942. Fertility in the male domestic fowl. Missouri Agr. Exp. Sta. Res. Bui. 347: 1-50. Rowell, J. G., and D. M. Cooper, 1957. The relation between fertility in the fowl and the dilution rate of the semen using a glycine diluent. Poultry Sci. 36: 706-712. Van Tienhoven, A., and R. G. D. Steel, 1957. The effect of different diluents and dilution rates on fertilizing capacity of turkey semen. Poultry Sci. 36: 473-479. Weakley, C. E., I l l , and C. S. Shaffner, 1952. The fertilizing capacity of diluted chicken semen. Poultry Sci. 31:650-653.
An Estimate of the Threonine Requirement of the Laying Hen* J. S. ADKINS, E. C. MILLEB, H. R. BIRD, C. A. ELVEHJEM AND M. L. SUNDE Departments of Poultry Husbandry and Biochemistry, University of Wisconsin, Madison 6, Wisconsin (Received for publication April 7, 1958)
I
N FEEDING laying hens purified diets that contain all amino acid nitrogen in place of intact protein, the largest expense is for the essential amino acid, threonine. While the level of threonine required by the chick (0.60 percent; Alm-• quist, 1947) is known, the requirement of: the laying hen is not established. In all[ Published with the approval of the Director ofi the Wisconsin Agricultural Experiment Station,, College of Agriculture, Madison, Wisconsin. * Supported in part by the Research Committee\ of the Graduate School from funds supplied by the Wisconsin Alumni Research Foundation, Madison, Wisconsin.
cases where the amino acid requirement has been established for the laying hen (isoleucine, Miller et al., 1954; leucine, Machlin, 1955; lysine and tryptophan, Ingram et al. 1951a; methionine, Ingram et al., 1951b, Leong and McGinnis, 1951), it was found to be less than the chick requirement. If the threonine requirement of the laying hen could be established, it could result in a considerable reduction in the expense of feeding purified diets containing alpha amino acids. The possibility of an imbalance or toxicity developing from too much threonine must also be considered. In the following three experi-
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 30, 2015
tion of fertility, which was more pronounced the second week after insemination than the first. There was little change in fertility when the seminal plasma was replaced by the buffer following centrifugation. A two-fold concentration of semen resulted in a slight improvement of fertility when compared with the seminal plasma replaced with an equal quantity of buffer. Fertility was not improved when the amount of diluted semen (1 to 10 or 1 to 20) inseminated was increased from 0.1 to 0.2 ml. Hatchability was unaffected by dilution.
1363
THREONINE REQUIREMENT OF THE LAYING H E N
ments designed to ascertain the threonine requirement of the laying hen, various levels of threonine were added to diets containing seven or eight percent crude casein. The remaining protein was supplied by crystalline amino acids. EXPERIMENTAL
All of the amino acid requirements of the laying hen established to date were accomplished by using crude protein which was deficient in one of the essential amino acids. Since all proteins contain adequate threonine to meet the requirement of the chicken when incorporated into the diet at the recommended protein level, this method could not be used to establish the threonine requirement. A Wisconsin practical all mash ration for laying hens producing market eggs, analyzing 16.0 percent protein, contains 0.87 percent L-threonine, (calculation based on values of Lyman et al., 1956). This figure represents 1.45 times the threonine requirement of the chick. In order to formulate a diet that was low in threonine, it was necessary to use a lower level of intact protein in the diet than is
7 percent 8 percent 17 percent casein casein casein
%
L-arginine HC1 0.60 L-tyrosine 0.70 DL-phenylalanine 0.60 DL-tryptophan 0.20 DL-methionine 0.50 DL-leucine 0.40 DL-isoleucine (44 percent L) 0.40 DL-valine 0.60 L-glutamic acid 4.00 Glycine 1.00 Crude casein 7.00 Alphacel 5.00 Feeding oil (1,S00A-300D) 0.50 Salts V* 6.00 Alpha tocopherol (0.6 mg./gm.) 0.50 Choline chloride (70 percent) 0.10 Soybean oil 3.00 Vitamin mixf 0.50 Antiacid Dextrin 68.40 Calculated Productive Energy (Calories/pound) 925 Protein percent (by analysis) 12.5
—.
%
0.60 0.70 0.60 0.20 0.50 0.40 0.40 0.60 4.00 1.00 8.00 5.00 0.50 6.00 0.50 0.10 9.50 0.50 1.00 59.90 1030 13.4
%
0.34
— — — — — — — 0.50 0.10
17.00
—
0.50 6.00 0.50 0.10 2.50 0.50
— .
71.96 1051 16.4
* Briggs el al. (1943). f Vitamin mix supplies the following vitamins in milligrams per kilogram of diet: thiamine HC1 6; biotin 0.2; pyridoxine HC1 4; menadione 0.5_; folic acid 4.0; riboflavin 6.0; calcium pantothenate 20.0; niacin 50.0; inositol 1,000.0; and vitamin B12 0.03.
recommended by the National Research Council Publication 301 (Bird et al., 1954) and supplement the diet with the essential amino acids to meet the requirements of the hen. The composition of the diets used in the following experiments is given in Table 1. The diets contained seven or eight percent crude casein which supplied 0.27 or 0.32 percent L-threonine. The threonine content of the diet was determined by the microbiological assay method of Henderson and Snell (1948) using 5. fecalis as the test organism. The amino acids added to the diet supplied 6.03 percent of equivalent protein (calculated from the nitrogen contained in the amino acids X 6.25). Kjeldahl analysis of this diet showed it to contain 12.5 percent equivalent protein (N X 6.25). Previous experiments show that this level of protein in the diet is adequate for good egg production (Miller et al., 1957) and (Thornton el al., 1957). The level of threonine required would probably vary slightly from that found in this experiment if a 15 percent protein diet were fed.
Downloaded from http://ps.oxfordjournals.org/ at New York University on April 30, 2015
Groups of two Single Comb White Leghorn pullets were kept in laying batteries with raised wire floors. Feed, water and oyster shells were supplied ad libitum. The pullets were placed on a purified diet containing 17 percent casein to accustom them to this type of diet before they were placed on the experimental diets. Only pullets with rates of egg production over 60 percent were selected for the experiments. The pullets were artificially inseminated weekly with pooled semen from New Hampshire males. The eggs were collected daily and pedigree hatched. At the time of setting, all eggs were weighed individually. All eggs which failed to hatch were broken out to determine the age of the embryos at death.
TABLE 1.—Composition of basal diets
1364
J. S. ADKINS, E. C. MILLER, H. R. BIRD, C. A. ELVEHJEM AND M. L. SUNDE
RESULTS AND DISCUSSION Egg Production. Table 2 shows that better egg production was obtained when the diet contained 0.42 percent L-threonine or higher levels than when it contained lower levels of threonine in two out of the three experiments. In the first experiment, birds fed 0.47 percent L-threonine or a higher level exceeded the egg
TABLE 2.—Effect of dietary threonine levels on egg production* Percent Experi- Experi- ExperiAve of 3 L-threoment 1 ment 2 ment 3 experinine in (9 weeks) (7 weeks) (7 weeks) ments the diet 0.27 0.32 0.37 0.42 0.47 0.52 0.57 0.62 17 percent casein control (0.66)
28.5 33.0 28.0 24.5f 47.5
%
%
%
45.5 50.0 43.0
27.5 25.5 45.8 49.0 76.2
53.0
33.5
56.0
23.5
57.5
%
51.7*
26.0 30.2 33.0 40.1 46.5 76.2 43.2 51.7
64.2
59.2
* 2 birds per group in all experiments. f 1 bird died during 4th week of experiment. j 1 bird died during 3rd week of experiment.
production of birds receiving lower levels of threonine. Egg production of hens receiving 0.27, 0.32 or 0.37 percent L-threonine averaged 29.8 percent production for the three experiments while those fed higher levels had a weighted average of 47.4 percent production for the seven or nine week experimental period. The highest production was obtained in experiment 3. The group of only two birds receiving 0.52 percent L-threonine averaged 76.2 percent production. If this group is excluded, the remainder of the pullets receiving more than 0.37 percent L-threonine averaged 45.4 percent production. The poorest production for any experiment was obtained on the basal diet in experiment 2. This group receiving 0.27 percent L-threonine averaged 23.5 percent production. The control birds, fed a 17 percent casein diet, averaged 59.2 percent production during the period. Body Weight Maintenance. Apparently the type of diet fed imposed a stress on the birds, since in most cases a loss in body weight occurred during the experimental period regardless of the level of threonine supplementation, (Table 3). The greatest
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The diets contained 925 or 1,030 Calories of productive energy per pound (calculated from the values of Titus, 1955). The dextrin productive energy value used was 1,100 Calories per pound. DL-threonine (alio free) was used to supplement the diets. It has been shown by Grau (1949) that DL-threonine is only one-half as active as the L-isomer for chicks. In supplementing with DL-threonine in the experiments reported here, it was assumed that the D-isomer of threonine was not utilized by the laying hen. The crystalline amino acids added in the diets were premixed to insure uniformity. Each amino acid was weighed and placed in a mortar and then several amino acids were ground together. After grinding in the mortar, the amino acids were placed in a large plastic bag and mixed thoroughly and then reground in the mortar to assure complete uniformity of the amino acid premix. In the last experiment one percent of an antiacid mixture (one part aluminum hydroxide to three parts magnesium trisilicate) was added to the diet. It was reported (Fisher et al., 1956) that an antiacid adsorbent, originally introduced in diets to prevent development of bleeding ulcers also helped to prevent early stoppage of feed consumption and egg production of hens fed an amino acid diet. Graded levels of threonine were added to the basal diet to determine the minimum level required for egg production and body weight maintenance.
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THREONINE REQUIREMENT OF THE LAYING H E N TABLE 3.—Effect
of various levels of threonine in the diet on body weight maintenance Casein control
Total percent L-threonine Average change in weight (gms.)
0.27 -412
0.32 -160
0.37 -162
0.42* -65
0.47 -67
0.52 -92
0.57 -56
0.62f -108
0.66 +3
• 1 bird died 4th week of experiment, f 1 bird died 3rd week of experiment.
TABLE 4.—Effect
GRAMS
2100
_
FIG. 1. Effect of threonine on body weight maintenance. Basal diets Al and A2 contained 0.27 and 0.32% L threonine respectively. Diet A3, 0.42% L threonine; A4, 0.57% L threonine; A5, 0.66% L threonine (17% Casein Control).
higher levels was better than that of hens on diets containing lower levels of threonine. Egg Size and Hatchability. Table 5 contains a summary of egg weights. The level
of various levels of threonine in the diet on feed consumption and utilization Casein control
Total percent L-threonine Grams of feed per bird/wk. Grams of feed per egg
0.27 491 256
* 1 bird died 4th week of experiment, f 1 bird died 3rd week of experiment.
0.32 450 233
0.37 509 209
0.42* 623 157
0.47 558 161
0.52 699 130
0.57 575 208
0.62f 600 149
0.66 825 154
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loss in body weight occurred in the groups receiving the basal diets. Hens fed the basal diet (0.27 percent L-threonine) lost an average of 412 grams. When the diet contained 0.32 or 0.37 percent L-threonine, the losses in body weight were not as great (160 and 162 grams respectively). Hens fed 0.42 percent L-threonine or higher levels lost an average of 77.6 grams. The control birds gained an average of three grams. Figure 1 shows that the birds require a depletion period of about five weeks or longer before maximum loss of body weight is noted. Feed Consumption and Utilization. Table 4 contains a summary of measurements of feed consumption. Feed consumption ranged from 450 to 825 grams of feed per bird per week. The levels of threonine supplementation had an inconsistent effect on the feed consumption. There was a trend toward higher consumption of birds fed higher levels of threonine. The hens fed the basal diets consumed less feed than other groups. Feed utilization of the hens on diets supplying 0.42 percent L-threonine or
1366
J. S. ADKINS, E. C. MILLER, H. R. BIRD, C. A. ELVEHJEM AND M. L. SUNDE
TABLE 5.—Effect of various levels of threonine in the diet on egg size Average egg weights (gms.) Percent of L-threonine • in diet
Week 1
2
0.27 55.8 49.0 0.32 52.2 46.5 0.37 50.2 51.1 0.42 54.9 51.8 0.47 55.9 53.5 0.57 54.3 53.6 0.62 52.9 52.7 Casein control (0.66) 55.9 55.4
3
4
5
6
7
52.0 52.0 49.5 51.6 50.4 52.1 54.5
51.0 49.5 51.0 54.2 54.0 53.7 54.6
47.0 42.1 49.0 53.5 54.7 54.3 55.4
48.0 49.7 48.3 52.3 51.7 53.1 54.5
56.0* 51.0 51.0 52.8 53.9 54.0 54.0
52.7
55.7
55.5
54.4
56.1
nine requirement of the laying hen has been made using crude casein supplemented with crystalline amino acids as the sources of protein in the ration. When egg production, feed consumption, body weight maintenance and egg size are considered, it appears that the L-threonine requirement of the laying hen approximates 0.42 percent of the diet. REFERENCES
of threonine used in the diets for this experiment had an inconsistent effect on egg size. There was a trend toward small eggs from birds fed the lower levels of threonine (0.27, 0.32 and 0.37). Birds fed 0.42 percent L-threonine or higher maintained a fairly constant egg size throughout the experimental period. The greatest variation was noted from hens fed the basal diet containing 0.32 percent threonine. The egg size decreased from an average of 52.2 grams at the beginning of the experiment to an average of 42.1 grams by the fifth week of the experiment. Apparently a depletion period is required before a dietary effect can be noted on the egg size of a hen. The level of threonine supplementation did not have any effect on hatchability as hatchability was excellent for all groups throughout all experiments. Since the laying hen requires 15 percent protein (Bird et al., 1954) in the diet as compared to 20 percent required by the chick, 75 percent of the threonine requirement of the chick (0.6 percent Lthreonine) should be adequate to meet the requirement of the laying hen (0.45 percent L-threonine). It is of interest to note that levels below 0.42 percent were inferior to higher levels. SUMMARY
A quantitative estimation of the threo-
Almquist, H. J., 1947. Evaluation of the amino acid requirement by observation on the chick. J. Nutrition, 34: 543-564. Bird, H. R., H. J. Almquist, W. W. Cravens, F. W, Hill and J. McGinnis, 1954. Nutrient requirements for domestic animals No. 1. Nutrient requirements for poultry. National Research Council Publication No. 301, Washington 25, D. C. Briggs, G. M., Jr., T. G. Luckey, C. A. Elvehjem and E. B. Hart, 1943. Study on two chemically unidentified water soluble vitamins necessary for the chick. J. Biol. Chem. 148: 163-172. Fisher, H., and D. Johnson, Jr., 1956. The amino acid requirement of the laying hen. J. Nutrition, 60: 261-273. Grau, C. R., 1949. The threonine requirement of the chick. J. Nutrition, 37: 105. Henderson, L. M., and E. E. Snell, 1948. A uniform medium for determination of amino acids with various microorganisms. J. Biol. Chem. 172: 15-30. Ingram, G. R., W. W. Cravens, C. A. Elvehjem and J. G. Halpin, 1951a. Studies on lysine and tryptophan requirements of the laying hen. Poultry Sci. 30: 426-430. Ingram, G. R., W. W. Cravens, C. A. Elvehjem and J. G. Halpin, 1951b. The methionine requirement of the laying hen. Poultry Sci. 30: 431^134. Leong, K. C , and J. McGinnis, 1951. An estimate of the methionine requirement for egg production. Poultry Sci. 31: 692-699. Lyman, C. M., K. A. Kuiken and F. Hale, 1956. Essential amino acid content of farm feeds. Agr. Food Chem. 4: 1008-1013. Machlin, L. J., 1955. An estimate of the leucine requirement of the laying hen. Poultry Sci. 34: 984-985. Miller, E. C , M. L. Sunde, H. R. Bird and C. A. Elvehjem, 1954. The isoleucine requirement of the laying hen. Poultry Sci. 33: 1201-1209.
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* 1 egg only.
THREONINE REQUIREMENT OF THE LAYING H E N Miller, E. C , M. L. Sunde and C. A. Elvehjem, 1957. Minimum protein requirement of laying pullets at different energy levels. Poultry Sci. 36: 681-690. Thornton, P. A., L. G. Blaylock and R. E. Moreng,
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1957. The protein level as a factor in egg production. Poultry Sci. 36: 552-557. Titus, H. W., 1955. Scientific Feeding of Chickens, 2nd edition. Interstate Printers and Publishers, 19-27 North Jackson Street, Danville, Illinois.
C . W . WOODMANSEE2 AND 0 . J . ABBOTT 3 Delaware Agricultural Experiment Station, Newark, Delaware (Received for publication April 7, 1958)
T
HE temperature which is used commonly for scalding in the commercial processing of poultry is about 128°F., generally referred to as semi-scalding. Within the last few years there has been a trend toward increasing the temperature to about 140°F., commonly known as sub-scalding, for certain types of poultry products. This higher temperature of scald facilitates the removal of feathers, especially the pin-feathers, thereby reducing substantially the labor required for this operation according to Gwin (1950, 1951, 1952). The relative merits of subscalding versus semi-scalding have been discussed by Line weaver and Klose (1952). In comparison to semi-scalded birds which retain a normal skin appearance, sub-scalded broilers have an altered skin appearance because the rubber fingers of the mechanical pickers remove part or the whole of the outer epidermal portion of the skin. This altered skin surface is more susceptible to dehydration and darkening during processing, storage, and mar1
Published as Miscellaneous Paper No. 301 with the approval of the Director of the Delaware Agricultural Experiment Station. 2 Department of Agricultural Chemistry. 8 Department of Animal and Poultry Industry.
keting as shown by observations such as those of Klose and Pool (1954) and Pool, Mecchi, Lineweaver and Klose (1954). Ziegler and Stadelman (1955) found that the shelf-life of sub-scalded birds was shorter than that of semi-scalded birds when stored at refrigerator temperature in polyethylene bags as indicated by an earlier development of off-odor and slime. Tests made by Graf and Stewart (1953) for the Quartermaster Food and Container Institute of the Armed Forces recommend the sub-scald treatment provided the broilers are not air chilled or the skin permitted to become dry. Although the sub-scalding process reduces hand pinning substantially in the processing industry, its use has been confined primarily to the dressing of birds for the quick-frozen trade (Gwin, 1951). It occurred to the authors that the application of a moisture resistant coating following the sub-scald treatment would afford protection against dehydration and darkening similar to that provided by the natural skin coating retained in the semiscald treatment. A report in the Chemical and Engineering News (1955) suggested the potential use of acetoglycerides as an edible, skin-tight coating on meats al-
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Coating Sub-Scalded Broiler Parts in Order to Afford Protection against Dehydration and Skin Darkening in Fresh Storage1