1886
D. M. CASSIDY, M. A. GIBSON AND F. G. PROUDFOOT
served in birds showing the "flip-over" syndrome , offering the possibility that they might be the immediate cause of death. However, the present study provides evidence that these structures are blood clots and are probably of post-mortem origin.
REFERENCES
Metabolizable Energy (M.E.) Values of Three Protein Supplements as Determined With Chicks and Laying Hens 1 F . HORANI 2 AND N . J . DAGHIR
Faculty of Agricultural Sciences, American University of Beirut, Beirut,
Lebanon
(Received for publication January 29, 1975)
ABSTRACT The M.E. values of three protein supplements that are produced and/or processed in Lebanon and Jordan were determined employing the method of Hill and Anderson (1958). Two experiments were conducted using broiler-type chicks in one experiment and White Leghorn laying hens in the other experiment. Nitrogen-corrected M.E. values expressed in kcal./kg. dry matter were found to be 2513, 2690 and 3215 for the soybean, sesame and poultry by-product meals, respectively, as determined with chicks, and 2522, 2747 and 3155 as determined with laying hens. Hence, it was concluded that chicks were as efficient as laying hens in energy utilization of these protein supplements. For all practical purposes, it was recommended that metabolizable energy values, of commonly used protein supplements, determined with either chicks or laying hens could be used in poultry ration formulation. POULTRY SCIENCE 54: 1886-1889, 1975
Middle East area. One of these
INTRODUCTION
A
NUMBER
of
protein
supplements
which are used in poultry rations are
locally produced a n d / o r processed in the
feedstuffs
is soybean meal which often is the major source of protein in poultry rations. In Lebanon, besides imports of soybean meal, soybean seeds are imported from the U.S. and Europe, and processed locally. Another
1. Contribution from the Faculty of Agricultural Sciences, American University of Beirut, as Journal Number 448. 2. Present address: Poultry Research Center, N.D.S.U. Fargo, N. Dak. 58102.
protein supplement which is processed in Jordan and used in poultry rations in that country is sesame meal. Poultry by-product meal is the third protein supplement included
Downloaded from http://ps.oxfordjournals.org/ at EKU Libraries,SerialsEastern Kentucky University on May 24, 2015
Dunnigan, M. G., 1968. The use of Nile blue sulphate in histochemical identification of phospholipids. Stain Technol. 43: 249-256. Freiman, D., 1971. Concepts of Disease—A Textbook of Human Pathology. J. G. Brunson and E. A. Gall, Eds. The MacMillan Co., New York. Gibson, M. A., 1966. A technique for the demonstration of endochondral ossification. Can. J. Zool. 44: 496-498.
Lillie, R. D., 1965. Histopathologic Technique and Practical Histochemistry. 3rd Ed. McGraw-Hill Co., New York. Miale, J. B., 1967. Laboratory Medicine: Hematology. The C. V. Mosby Co., Saint Louis. Pearse, A. G. E., 1961. Histochemistry, Theoretical and Applied. J. and A. Churchill Ltd., London. Poole, J. C. F., and J. E. French, 1961. Thrombosis. J. Atherosclerosis Res. 1: 251-282. Runnels, R. W. Monlux and A. Monlux, 1965. Principles of Veterinary Pathology. The Iowa State University Press, Iowa. Smith, H. A., T. C. Jones and R. D. Hunt, 1972. Veterinary Pathology. Lea and Febiger. Philadelphia, Pa. Thompson, S. W., 1966. Selected Histochemical and Histopathological Methods. C. C Thomas, Springfield, 111.
1887
METABOLIZABLE ENERGY
TABLE 1.—Percentage composition of the reference diets
Glucose Soybean meal Yellow corn Alfalfa meal (17% protein) Fish meal (65% protein) Casein Corn oil Bone meal Limestone Salt Vitamin and mineral mixture' Chromic oxide premix 2 1
Reference chick diet
Reference laying hen diet
42.1 15.0 17.6
20.0 18.5 46.0
2.0 5.0 10.0 2.5 2.5 1.0 0.5
2.0 2.0
0.3 1.5
— — 2.7 6.5 0.5 0.3 1.5
The vitamin and mineral mixture for the chick diet supplied the following per kg. ration: 10,560 I.U. vitamin A; 2,640 I.C.U. vitamin D 3 ; 9.9 I.U. vitamin E; 5.28 mg. riboflavin; 1.32 mg. thiamine; 9.72 mg. D-pantothenic acid; 39.6 mg. niacin; 528 mg. choline chloride; 0.013 mg. vitamin B 12 activit y ^ . 396 mg. folic acid; 2.64 mg. menadione sodium bisulfite complex; 0.15 mg. BHT; 72 mg. manganese; 52.92 mg. zinc; 24 mg. iron; 2.4 mg. copper; 1.44 mg. iodine; 0.24 mg. cobalt. The vitamin and mineral mixture for the laying hen diet supplied the following per kg. ration: 7,920 I.U. vitamin A; 1,980 I.C.U. vitamin D 3 ; 2.54 I.U. vitamin E; 5.28 mg. riboflavin; 7.26 mg. D-pantothenic acid; 33.0 mg. niacin; 330.0 mg. niacin; 330.0 mg. choline chloride; 2.54 mg. menadione sodium bisulfite complex; 105.6 \xg. vitamin B 1 2 ; 149.7 mg. BHT; 72.0 mg. manganese; 33.06 mg. zinc; 24.0 mg. iron; 2.4 mg. copper; 1.44 mg. iodine; 0.24 mg. cobalt. 2 Contained chromic oxide and wheat flour in the ratio of 1:2, respectively.
of a feedstuff, the objective of this study was primarily to determine the M.E. values of the three protein supplements mentioned above. Another objective was to find if there are differences in M.E. values of these feedstuffs when determined with chicks and with laying hens. EXPERIMENTAL PROCEDURE Chick Experiment. One hundred and twenty, male commercial broiler-type chicks were allotted to groups of ten chicks each equalizing both mean body weight and body weight distribution among the groups. All groups were placed in a Petersime battery brooder equipped with wire floors and thermostatically controlled heating units. Each diet was fed to three groups, including the reference diet whose composition is shown in Table 1. Part of the glucose in the reference diet was substituted by either soybean meal, sesame meal or poultry by-product meal. The proximate analysis of these feedstuffs is shown in Table 2. Chromic oxide was incorporated in each diet at a level of 0.5% as an index material. Samples of excreta were collected on the last three days of the experimental period. The collected excreta were freeze-dried, finely ground and kept in glass jars for analysis. Both feed and excreta samples were analyzed for moisture, nitrogen, gross energy and chromic oxide content.
TABLE 2.—Proximate analysis of the soybean, sesame and poultry by-product meals used in this study* Soybean Sesame meal meal Moisture Protein Ether extract Fiber Ash N.F.E.
Poultry by-product meal
%
%
%
7.37 46.40 2.25 5.91 10.13 27.94
9.78 44.75 8.50 5.62 9.84 21.51
3.92 74.00 15.64 1.27 2.17 3.00
*Values are averages of two samples run in duplicate.
Downloaded from http://ps.oxfordjournals.org/ at EKU Libraries,SerialsEastern Kentucky University on May 24, 2015
in this study, and it is produced by poultry processing plants in Lebanon. This meal is a fine-textured by-product resulting from the processing of the viscera, blood and feathers of chickens. Since data on the nutritive value of many Middle Eastern poultry feedstuffs are relatively scarce, and since metabolizable energy (M.E.) could be considered among the best criteria for judging the overall nutritive value
1888
F . HORANI AND N . J . DAGHIR
RESULTS AND DISCUSSION Nitrogen-corrected M.E. values were calculated as described by Hill and Anderson (1958). Table 3 shows the determined M.E. values of the three feedstuffs tested with chicks and with laying hens. The M.E. values obtained for each feedstuff tested showed no statistically significant difference (Snedecor and Cochran, 1967) whether chicks or laying hens were used as the experimental animals. The results suggest that chicks were as efficient as laying hens in digesting and utilizing the energy content of the protein supplements tested. This is in agreement with the conclusions of Hill and Renner (1963), SUI-
TABLE 3.—M.E. values of soybean, sesame and poultry by-product meals Gross
Ingredient Soybean meal Chicks Sesame meal Poultry by-product meal Soybean meal Layers Sesame meal Poultry by-product meal
M.E. (D.M.) (Kcal./kg.) 2513 ± 145* 2690 ± 162
energy metabolized % 54.6 55.8
3215 ± 95 2522 ± 104 2747 ± 85
56.4 54.8 57.0
3155 ± 110
55.3
'Average of three replicates ± S.E.
bald et al. (1960) and Daghir and Nathanael (1974), but in contrast with previous studies by Sell (1966) and Lodhi et al, (1969), and recent studies by Petersen et al. (1973) who found significant differences in M.E. values for ten ingredients, especially those with higher fiber contents, between chicks and hens. The discrepancy in results among workers may be partially due to differences in the nature of the feedstuffs studied (processing, variety, presence of toxins, etc.) which in turn influence utilization by the chicks and the laying hens. Rao and Clandinin (1970) studied the effect of method of determination on the M.E. value of rapeseed meal for starting chicks, and found that the M.E. value as obtained by the method of Hill and Anderson (1958) was significantly lower than when obtained by the method of Sibbald and Slinger (1963). However, Rao and Clandinin (1970) who reviewed the discrepancy in the M.E. values of rapeseed meal obtained by Sibbald and Slinger (1963), Sell (1966), and Lodhi et al. (1969), failed to note that the M.E. value of rapeseed meal for laying hens reported by Sell (1966) was significantly higher than the value reported by Lodhi et al. (1969) even though the method of determination employed was the same. Childs (1972) suggested that such differences in M.E. values may be attributed to variation of ingredient samples, dietary nutrient levels, age of animals, fats as well as many other factors. For all practical purposes it seems valid to conclude that the M.E. values of commonly used protein supplements obtained with either chicks or laying hens could be used in poultry ration formulation.
REFERENCES Childs, G. R., 1972. Factors affecting the metabolizable energy values of feedstuffs for poultry. Feedstuffs, 44: 39-49. Daghir, N. J., and A. S. Nathanael, 1974. An assessment of the nutritional value of triticale for poultry.
Downloaded from http://ps.oxfordjournals.org/ at EKU Libraries,SerialsEastern Kentucky University on May 24, 2015
Laying Hen Experiment. The reference diet was similar to that used by Sell (1966) and is shown in Table 1. Soybean, sesame and poultry by-product meals were each substituted for all the glucose in the reference diet to equalize the level of substitution in this experiment with that in the chick experiment. Each diet was fed for two weeks to 3 lots of 3 Single Comb White Leghorn hens of about 10 months of age, maintained in individual wire-floor cages. Excreta were collected on the last three days of the experimental period and treated as in the experiment with chicks.
METABOLIZABLE ENERGY
Rao, P. V., and D. R. Clandinin, 1970. Effect of method of determination on the metabolizable energy value of rapeseed meal. Poultry Sci. 49: 10691074. Sell, J. L., 1966. Metabolizable energy of rapeseed meal for the laying hen. Poultry Sci. 45: 854-856. Sibbald, I. R., J. D., Summers and S. J. Slinger, 1960. Factors affecting the metabolizable energy content of poultry feeds. Poultry Sci. 39: 544-556. Sibbald, I. R., and S. J. Slinger, 1963. A biological assay for metabolizable energy in poultry feed ingredients together with findings which demonstrate some of the problems associated with the evaluation of fats. Poultry Sci. 42: 313-325. Snedecor, G. W., and W. G. Cochran, 1967. Statistical Methods. Sixth edition. The Iowa State University Press. Ames, Iowa.
Perspective on Evaporative Chilling of Poultry A. A. KLOSE
Richard B. Russell Research Center, United States Department of Agriculture, P.O. Box 5677, Athens, Georgia 30604 (Received for publication February 3, 1975)
ABSTRACT The feasibility of evaporative chilling of warm eviscerated broilers and retail parts was investigated on a laboratory (all glass) scale, with diffusion and mechanical vacuum pumps and an alcohol-dry ice condenser. Required chilling times were similar to those for present commercial ice slush immersion methods. Weight losses were as high as 5%, but could be controlled by dipping the carcasses in 1% aqueous methyl cellulose before chilling. Ballooning of the skin during chilling had little or no effect on final appearance. Evaporative chilling of poultry has a potential as a non-immersion chilling method if we are prepared to sacrifice the substantial weight gains provided by current immersion methods. POULTRY SCIENCE 54: 1889-1893, 1975
M
OST chilling methods (including cold air, liquid nitrogen, carbon dioxide, ice water immersion, water spray, and contact plate) have been applied commercially to some forms of poultry at some time. An exception is evaporative chilling. This may be due to lack of equipment, equipment and operating costs, moisture loss, and changes in appearance of product, or a combination of these factors. Commercial applications of evaporative chilling have been successful in other food fields. Lettuce, in car load lots, has been chilled this way for over 25 years. Many other high moisture vegetables, such as endive, escarole, parsley, spinach, brocco-
li and cauliflower (Bennett, 1971) are vacuum cooled. Evaporative or vacuum chilling is most successful with products of high surface to volume ratio. However, some products of low surface to volume ratio, e.g. carrots, are also vacuum cooled. In the process, water in the product or sprayed on the surface is evaporated by reducing pressure continually below equilibrium water vapor pressure at product temperature. Although moisture loss is significant, the net loss from the fresh weight may be reduced by an initial spray of water on the product surface. In discussing the possibility of freezing fresh foods prior to freeze drying by evaporation of surface
Downloaded from http://ps.oxfordjournals.org/ at EKU Libraries,SerialsEastern Kentucky University on May 24, 2015
XV World Poultry Congress Proc: 612-614. Hill, F. W., and D. L. Anderson, 1958. Comparison of metabolizable energy and productive energy determinations with growing chicks. J. Nutr. 64: 587602. Hill, F. W., and R. Renner, 1963. Effect of heat treatment on the metabolizable energy value of soybeans and extracted soybean flakes for the hen. J. Nutr. 80: 375-380. Lodhi, G. N., R. Renner and D. R. Clandinin, 1969. Studies on the metabolizable energy of rapeseed meal for growing chicks and laying hens. Poultry Sci. 48: 964-970. Petersen, C. F., E. A. Sauter and G. B. Meyer, 1973. Comparison of metabolizable energy values of feed ingredients for chicks and hens. Poultry Sci. 52: 2073.
1889
D. M. CASSIDY, M. A. GIBSON AND F. G. PROUDFOOT
served in birds showing the "flip-over" syndrome , offering the possibility that they might be the immediate cause of death. However, the present study provides evidence that these structures are blood clots and are probably of post-mortem origin.
REFERENCES
Metabolizable Energy (M.E.) Values of Three Protein Supplements as Determined With Chicks and Laying Hens 1 F . HORANI 2 AND N . J . DAGHIR
Faculty of Agricultural Sciences, American University of Beirut, Beirut,
Lebanon
(Received for publication January 29, 1975)
ABSTRACT The M.E. values of three protein supplements that are produced and/or processed in Lebanon and Jordan were determined employing the method of Hill and Anderson (1958). Two experiments were conducted using broiler-type chicks in one experiment and White Leghorn laying hens in the other experiment. Nitrogen-corrected M.E. values expressed in kcal./kg. dry matter were found to be 2513, 2690 and 3215 for the soybean, sesame and poultry by-product meals, respectively, as determined with chicks, and 2522, 2747 and 3155 as determined with laying hens. Hence, it was concluded that chicks were as efficient as laying hens in energy utilization of these protein supplements. For all practical purposes, it was recommended that metabolizable energy values, of commonly used protein supplements, determined with either chicks or laying hens could be used in poultry ration formulation. POULTRY SCIENCE 54: 1886-1889, 1975
Middle East area. One of these
INTRODUCTION
A
NUMBER
of
protein
supplements
which are used in poultry rations are
locally produced a n d / o r processed in the
feedstuffs
is soybean meal which often is the major source of protein in poultry rations. In Lebanon, besides imports of soybean meal, soybean seeds are imported from the U.S. and Europe, and processed locally. Another
1. Contribution from the Faculty of Agricultural Sciences, American University of Beirut, as Journal Number 448. 2. Present address: Poultry Research Center, N.D.S.U. Fargo, N. Dak. 58102.
protein supplement which is processed in Jordan and used in poultry rations in that country is sesame meal. Poultry by-product meal is the third protein supplement included
Downloaded from http://ps.oxfordjournals.org/ at EKU Libraries,SerialsEastern Kentucky University on May 24, 2015
Dunnigan, M. G., 1968. The use of Nile blue sulphate in histochemical identification of phospholipids. Stain Technol. 43: 249-256. Freiman, D., 1971. Concepts of Disease—A Textbook of Human Pathology. J. G. Brunson and E. A. Gall, Eds. The MacMillan Co., New York. Gibson, M. A., 1966. A technique for the demonstration of endochondral ossification. Can. J. Zool. 44: 496-498.
Lillie, R. D., 1965. Histopathologic Technique and Practical Histochemistry. 3rd Ed. McGraw-Hill Co., New York. Miale, J. B., 1967. Laboratory Medicine: Hematology. The C. V. Mosby Co., Saint Louis. Pearse, A. G. E., 1961. Histochemistry, Theoretical and Applied. J. and A. Churchill Ltd., London. Poole, J. C. F., and J. E. French, 1961. Thrombosis. J. Atherosclerosis Res. 1: 251-282. Runnels, R. W. Monlux and A. Monlux, 1965. Principles of Veterinary Pathology. The Iowa State University Press, Iowa. Smith, H. A., T. C. Jones and R. D. Hunt, 1972. Veterinary Pathology. Lea and Febiger. Philadelphia, Pa. Thompson, S. W., 1966. Selected Histochemical and Histopathological Methods. C. C Thomas, Springfield, 111.
1887
METABOLIZABLE ENERGY
TABLE 1.—Percentage composition of the reference diets
Glucose Soybean meal Yellow corn Alfalfa meal (17% protein) Fish meal (65% protein) Casein Corn oil Bone meal Limestone Salt Vitamin and mineral mixture' Chromic oxide premix 2 1
Reference chick diet
Reference laying hen diet
42.1 15.0 17.6
20.0 18.5 46.0
2.0 5.0 10.0 2.5 2.5 1.0 0.5
2.0 2.0
0.3 1.5
— — 2.7 6.5 0.5 0.3 1.5
The vitamin and mineral mixture for the chick diet supplied the following per kg. ration: 10,560 I.U. vitamin A; 2,640 I.C.U. vitamin D 3 ; 9.9 I.U. vitamin E; 5.28 mg. riboflavin; 1.32 mg. thiamine; 9.72 mg. D-pantothenic acid; 39.6 mg. niacin; 528 mg. choline chloride; 0.013 mg. vitamin B 12 activit y ^ . 396 mg. folic acid; 2.64 mg. menadione sodium bisulfite complex; 0.15 mg. BHT; 72 mg. manganese; 52.92 mg. zinc; 24 mg. iron; 2.4 mg. copper; 1.44 mg. iodine; 0.24 mg. cobalt. The vitamin and mineral mixture for the laying hen diet supplied the following per kg. ration: 7,920 I.U. vitamin A; 1,980 I.C.U. vitamin D 3 ; 2.54 I.U. vitamin E; 5.28 mg. riboflavin; 7.26 mg. D-pantothenic acid; 33.0 mg. niacin; 330.0 mg. niacin; 330.0 mg. choline chloride; 2.54 mg. menadione sodium bisulfite complex; 105.6 \xg. vitamin B 1 2 ; 149.7 mg. BHT; 72.0 mg. manganese; 33.06 mg. zinc; 24.0 mg. iron; 2.4 mg. copper; 1.44 mg. iodine; 0.24 mg. cobalt. 2 Contained chromic oxide and wheat flour in the ratio of 1:2, respectively.
of a feedstuff, the objective of this study was primarily to determine the M.E. values of the three protein supplements mentioned above. Another objective was to find if there are differences in M.E. values of these feedstuffs when determined with chicks and with laying hens. EXPERIMENTAL PROCEDURE Chick Experiment. One hundred and twenty, male commercial broiler-type chicks were allotted to groups of ten chicks each equalizing both mean body weight and body weight distribution among the groups. All groups were placed in a Petersime battery brooder equipped with wire floors and thermostatically controlled heating units. Each diet was fed to three groups, including the reference diet whose composition is shown in Table 1. Part of the glucose in the reference diet was substituted by either soybean meal, sesame meal or poultry by-product meal. The proximate analysis of these feedstuffs is shown in Table 2. Chromic oxide was incorporated in each diet at a level of 0.5% as an index material. Samples of excreta were collected on the last three days of the experimental period. The collected excreta were freeze-dried, finely ground and kept in glass jars for analysis. Both feed and excreta samples were analyzed for moisture, nitrogen, gross energy and chromic oxide content.
TABLE 2.—Proximate analysis of the soybean, sesame and poultry by-product meals used in this study* Soybean Sesame meal meal Moisture Protein Ether extract Fiber Ash N.F.E.
Poultry by-product meal
%
%
%
7.37 46.40 2.25 5.91 10.13 27.94
9.78 44.75 8.50 5.62 9.84 21.51
3.92 74.00 15.64 1.27 2.17 3.00
*Values are averages of two samples run in duplicate.
Downloaded from http://ps.oxfordjournals.org/ at EKU Libraries,SerialsEastern Kentucky University on May 24, 2015
in this study, and it is produced by poultry processing plants in Lebanon. This meal is a fine-textured by-product resulting from the processing of the viscera, blood and feathers of chickens. Since data on the nutritive value of many Middle Eastern poultry feedstuffs are relatively scarce, and since metabolizable energy (M.E.) could be considered among the best criteria for judging the overall nutritive value
1888
F . HORANI AND N . J . DAGHIR
RESULTS AND DISCUSSION Nitrogen-corrected M.E. values were calculated as described by Hill and Anderson (1958). Table 3 shows the determined M.E. values of the three feedstuffs tested with chicks and with laying hens. The M.E. values obtained for each feedstuff tested showed no statistically significant difference (Snedecor and Cochran, 1967) whether chicks or laying hens were used as the experimental animals. The results suggest that chicks were as efficient as laying hens in digesting and utilizing the energy content of the protein supplements tested. This is in agreement with the conclusions of Hill and Renner (1963), SUI-
TABLE 3.—M.E. values of soybean, sesame and poultry by-product meals Gross
Ingredient Soybean meal Chicks Sesame meal Poultry by-product meal Soybean meal Layers Sesame meal Poultry by-product meal
M.E. (D.M.) (Kcal./kg.) 2513 ± 145* 2690 ± 162
energy metabolized % 54.6 55.8
3215 ± 95 2522 ± 104 2747 ± 85
56.4 54.8 57.0
3155 ± 110
55.3
'Average of three replicates ± S.E.
bald et al. (1960) and Daghir and Nathanael (1974), but in contrast with previous studies by Sell (1966) and Lodhi et al, (1969), and recent studies by Petersen et al. (1973) who found significant differences in M.E. values for ten ingredients, especially those with higher fiber contents, between chicks and hens. The discrepancy in results among workers may be partially due to differences in the nature of the feedstuffs studied (processing, variety, presence of toxins, etc.) which in turn influence utilization by the chicks and the laying hens. Rao and Clandinin (1970) studied the effect of method of determination on the M.E. value of rapeseed meal for starting chicks, and found that the M.E. value as obtained by the method of Hill and Anderson (1958) was significantly lower than when obtained by the method of Sibbald and Slinger (1963). However, Rao and Clandinin (1970) who reviewed the discrepancy in the M.E. values of rapeseed meal obtained by Sibbald and Slinger (1963), Sell (1966), and Lodhi et al. (1969), failed to note that the M.E. value of rapeseed meal for laying hens reported by Sell (1966) was significantly higher than the value reported by Lodhi et al. (1969) even though the method of determination employed was the same. Childs (1972) suggested that such differences in M.E. values may be attributed to variation of ingredient samples, dietary nutrient levels, age of animals, fats as well as many other factors. For all practical purposes it seems valid to conclude that the M.E. values of commonly used protein supplements obtained with either chicks or laying hens could be used in poultry ration formulation.
REFERENCES Childs, G. R., 1972. Factors affecting the metabolizable energy values of feedstuffs for poultry. Feedstuffs, 44: 39-49. Daghir, N. J., and A. S. Nathanael, 1974. An assessment of the nutritional value of triticale for poultry.
Downloaded from http://ps.oxfordjournals.org/ at EKU Libraries,SerialsEastern Kentucky University on May 24, 2015
Laying Hen Experiment. The reference diet was similar to that used by Sell (1966) and is shown in Table 1. Soybean, sesame and poultry by-product meals were each substituted for all the glucose in the reference diet to equalize the level of substitution in this experiment with that in the chick experiment. Each diet was fed for two weeks to 3 lots of 3 Single Comb White Leghorn hens of about 10 months of age, maintained in individual wire-floor cages. Excreta were collected on the last three days of the experimental period and treated as in the experiment with chicks.
METABOLIZABLE ENERGY
Rao, P. V., and D. R. Clandinin, 1970. Effect of method of determination on the metabolizable energy value of rapeseed meal. Poultry Sci. 49: 10691074. Sell, J. L., 1966. Metabolizable energy of rapeseed meal for the laying hen. Poultry Sci. 45: 854-856. Sibbald, I. R., J. D., Summers and S. J. Slinger, 1960. Factors affecting the metabolizable energy content of poultry feeds. Poultry Sci. 39: 544-556. Sibbald, I. R., and S. J. Slinger, 1963. A biological assay for metabolizable energy in poultry feed ingredients together with findings which demonstrate some of the problems associated with the evaluation of fats. Poultry Sci. 42: 313-325. Snedecor, G. W., and W. G. Cochran, 1967. Statistical Methods. Sixth edition. The Iowa State University Press. Ames, Iowa.
Perspective on Evaporative Chilling of Poultry A. A. KLOSE
Richard B. Russell Research Center, United States Department of Agriculture, P.O. Box 5677, Athens, Georgia 30604 (Received for publication February 3, 1975)
ABSTRACT The feasibility of evaporative chilling of warm eviscerated broilers and retail parts was investigated on a laboratory (all glass) scale, with diffusion and mechanical vacuum pumps and an alcohol-dry ice condenser. Required chilling times were similar to those for present commercial ice slush immersion methods. Weight losses were as high as 5%, but could be controlled by dipping the carcasses in 1% aqueous methyl cellulose before chilling. Ballooning of the skin during chilling had little or no effect on final appearance. Evaporative chilling of poultry has a potential as a non-immersion chilling method if we are prepared to sacrifice the substantial weight gains provided by current immersion methods. POULTRY SCIENCE 54: 1889-1893, 1975
M
OST chilling methods (including cold air, liquid nitrogen, carbon dioxide, ice water immersion, water spray, and contact plate) have been applied commercially to some forms of poultry at some time. An exception is evaporative chilling. This may be due to lack of equipment, equipment and operating costs, moisture loss, and changes in appearance of product, or a combination of these factors. Commercial applications of evaporative chilling have been successful in other food fields. Lettuce, in car load lots, has been chilled this way for over 25 years. Many other high moisture vegetables, such as endive, escarole, parsley, spinach, brocco-
li and cauliflower (Bennett, 1971) are vacuum cooled. Evaporative or vacuum chilling is most successful with products of high surface to volume ratio. However, some products of low surface to volume ratio, e.g. carrots, are also vacuum cooled. In the process, water in the product or sprayed on the surface is evaporated by reducing pressure continually below equilibrium water vapor pressure at product temperature. Although moisture loss is significant, the net loss from the fresh weight may be reduced by an initial spray of water on the product surface. In discussing the possibility of freezing fresh foods prior to freeze drying by evaporation of surface
Downloaded from http://ps.oxfordjournals.org/ at EKU Libraries,SerialsEastern Kentucky University on May 24, 2015
XV World Poultry Congress Proc: 612-614. Hill, F. W., and D. L. Anderson, 1958. Comparison of metabolizable energy and productive energy determinations with growing chicks. J. Nutr. 64: 587602. Hill, F. W., and R. Renner, 1963. Effect of heat treatment on the metabolizable energy value of soybeans and extracted soybean flakes for the hen. J. Nutr. 80: 375-380. Lodhi, G. N., R. Renner and D. R. Clandinin, 1969. Studies on the metabolizable energy of rapeseed meal for growing chicks and laying hens. Poultry Sci. 48: 964-970. Petersen, C. F., E. A. Sauter and G. B. Meyer, 1973. Comparison of metabolizable energy values of feed ingredients for chicks and hens. Poultry Sci. 52: 2073.
1889
