Performance, Composition, and Quality of Broiler Chickens Fed Dried Whole Eggs1

Performance-, Composition, and Quality of Broiler Chickens Fed Dried Whole Eggs1 M. G. MAST,2 R. M. LEACH,3 and J. H. MacNEIL2 Departments of Food Science and Poultry Science, The Pennsylvania State University, University Park, Pennsylvania 16802 (Received for publication July 29, 1983) ABSTRACT Dried whole egg powder, prepared from - inedible eggs, was incorporated into the diet of broiler chickens throughout their 7-week growing period. Five diets were used: 1) control, no eggs, 2) 10% dried egg, 3) 10% dried egg, biotin enriched, 4) 20% dried egg, and 5) 20% dried egg, biotin enriched. Birds on the control diet were the largest when slaughtered, followed by the "10% egg diet" birds, and then the "20% egg diet" birds. Although the birds fed the 20% egg diet in which no additional biotin was added were significantly (P<.05) smaller than the other four treatments, their processing and cooking yields were not different. Meat from broilers fed the egg diets generally received flavor scores equal to or slightly higher than the control, as evaluated by sensory panelists. The "control" meat was usually rated slightly more tender than "egg diet" meat. The "control" meat also contained more fat and less moisture than meat from birds on egg diets. These results indicate that 10% dried whole egg can be added to broiler diets without adverse effects. When biotin-enriched eggs were used, a diet containing 20% dried whole egg proved acceptable. No economic considerations are included in these assumptions. (Key words: broiler diets, feed efficiency, sensory evaluation, dried eggs, processing yields, meat composition) 1984 Poultry Science 63:1940-1945 INTRODUCTION

Each year a large q u a n t i t y of leaker eggs and o t h e r inedible eggs needs to b e disposed of in some m a n n e r . Some egg packers collect this p r o d u c t and sell it to pet food or animal feed

m a n u f a c t u r e r s for a few cents per p o u n d . O t h e r egg packers and breakers have no good outlet and may even pay t o have t h e p r o d u c t removed. Mast ( 1 9 8 2 , u n p u b l i s h e d ) c o n d u c t e d a survey to assess t h e m a g n i t u d e of t h e leaker egg problem in Pennsylvania. Survey returns represented 7 5 % of t h e Pennsylvania egg p r o d u c t i o n , which was 4 . 3 2 bllion in 1 9 8 2 . Damaged or lost eggs represented 7.2% of total egg p r o d u c t i o n : 4.4% cracks, 1.1% leakers, .7% b l o o d s , and 1.0% o t h e r loss. T h e 1.1% leakers represent in excess of 2.25 million kg (5 million lb) of liquid egg annually in Pennsylvania t h a t is either lost or underutilized. The m e a n value received was ,5^/lb; however, 7 6 % of t h e survey r e s p o n d e n t s received n o t h i n g for their eggs. Outlets reported for leakers were o t h e r animal feed (on farm t o hogs), p e t food, spreading on fields, garbage, and rendering plants. Two-thirds of the res p o n d e n t s were dissatisfied with their current system for leaker egg disposal and their financial return from t h e p r o d u c t .

'Authorized for publication on July 18, 1983 as Paper No. 6727 in the Journal Series of the Pennsylvania Agricultural Experiment Station. 2 Department of Food Science. 3 Department of Poultry Science.

S o m e inedible eggs are incorporated directly into p e t foods or dried and used as feedstuffs for animals, especially m i n k . Dried eggs are n o t usually i n c o r p o r a t e d i n t o diets of laying hens or broilers, partly d u e t o costs involved in drying t h e eggs. An additional concern with large a m o u n t s of egg in chicken diets is t h e potential

T h e incidence of egg shell breakage in t h e United States is generally considered t o be 6 t o 8% (Roland, 1 9 7 7 ; Hamilton, 1 9 8 2 ; Washburn, 1 9 8 2 ) ; t o t a l annual p r o d u c t i o n is approxiately 7 0 billion shell eggs. Eggs classified as " c h e c k s " , in which t h e shell is cracked b u t t h e shell m e m b r a n e s are intact and t h e c o n t e n t s d o n o t leak, m a y be used as h u m a n food and are usually diverted into liquid or dried egg p r o d u c t s ; leakers, however, have b r o k e n shells and shell m e m b r a n e s to t h e e x t e n t that t h e c o n t e n t s are exuding or are free t o e x u d e t h r o u g h t h e shell (USDA, 1 9 8 3 ) . Since 1 9 7 2 , t h e Egg Products Inspection Act requires t h a t leakers, which are classified as "restricted eggs", m u s t be d e n a t u r e d or destroyed at the p o i n t of segregation t o prevent e n t r a n c e into c o n s u m e r f o o d channels.

1940

DRIED EGG IN BROILER DIETS

for a biotin deficiency to develop. Avidin in the egg, present at a maximum concentration of about .05% of the albumin protein (Green, 1975), can form a complex with biotin, rendering this essential vitamin unavailable. Biotin deficiencies in chicks are manifested by dermal lesions of the feet, eyelids, and angles of the beak, poor growth and feathering, and sometimes, deformed legs or perosis (Scott et al., 1982). Wehr et al. (1980) fed mink diets containing 5 or 10% spray-dried egg. Mink fed the diet with 10% dried egg developed classical symptoms of biotin deficiency. The authors concluded that spray-dried eggs are insufficiently heat treated to render avidin content inactive. In subsequent studies Oldfield and Adair (1981) fed mink diets containing 10 and 20% standard dried egg or biotin-enriched egg. Mink fed biotin-enriched dried egg were larger and had improved feed conversion compared with mink fed standard dried egg.

1941

The purpose of the present study was to determine the performance, composition, and quality of chicken broilers fed varying amounts of standard dried egg or biotin-enriched dried egg, which had been prepared from inedible eggs-

MATERIALS AND METHODS The broiler diets used in this study are shown in Table 1. Diet A, or control, contained no dried whole egg; Diets B and D contained 10% dried egg; and Diets C and E contained 20% dried egg. Diets D and E differed from B and C, respectively, in that they contained biotin-enriched dried egg. All diets were adjusted so that the metabolizable energy to protein ratio was about 143. The dried eggs were supplied by American Dehydrated Foods, Inc., Springfield, MO, and dried eggs were defined by them as pasteurized spray-dried, inedible, whole egg solids, pro-

TABLE 1. Composition of diets Diet A

Ground corn Soybean meal (49.0%) Dried egg Corn oil2 Vitamin mix 3 Trace mineral mix 4 NaCl NaH2P04-H20 KHC0 3 KH 2 P0 4 DL-Methionine Limestone

50.29 37.50 6.50 1.22 .50 .14

Diet B and D1 (.kg/iuu kg; 56.85 26.50 10.00 1.00 1.22

52.06 21.50 20.00 1.00 1.22

.20

.15

.50 .14 .48 .33 .09 .05

2.63

2.63

2.63

22.61 3225 142.6

22.67 3244 143.2

24.61 3523 143.2

1.02

.50 .14 .75 .26

Diet C and E1

Calculated analysis Protein, % Metabolizable energy, kcal/kg Metabolizable energy/ % Protein 1 2

Dried egg in Diets D and E is biotin enriched; contains 7.7 mg biotin/kg dried egg. Mazola corn oil, Best Foods, Englewood Cliffs, NJ.

3 Supplies (per kg of diet): inositol, .250 g; niacin, .050 g; calcium pantothenate, .020 g; pyridoxine HC1, .0045 g; folic acid, .004 g; menadione sodium bisulfite, .00152 g; biotin, .0002 g; thiamine, .011 g; riboflavin, .011 g; vitamin B 1 2 , 20 /ig; vitamin A, 5400 IU; vitamin D 3 980 IU; vitamin E, .066 g; choline chloride, 1.54 g; sucrose diluent.

"This mineral mix supplies (per kg of diet): F e S 0 4 - 7 H 2 0 , .33g;MgSO„, 2.50 g;KI, .0026 g; CuS0 4 • 5 H 2 0 , .0167 g; ZnC0 3 , .115 g; CoCl 2 -6H 2 O, .0017 g; NaMoO„-2H 2 0, .0083 g; NaSe0 3 • 5 H 2 0 , .0033 g; CrK(SO„ ) 2 • 12H 2 0, .020 g; sucrose diluent.

1942

MAST ET AL.

duced from eggs unacceptable for human consumption. Prior to spray drying, the liquid whole egg was pasteurized at 62 C for 5 min. Temperatures used in spray drying were 210 C for inlet air and 71 C for exhaust air. The biotin content of the nonenriched spray-dried egg used in Diets B and C was approximately 1.4 mg/kg, whereas the biotinenriched egg used in Diets D and E contained about 7.7 mg/kg. The vitamin mix (see Table 1) used in all diets contributed 200 jug biotin/kg of diet and the ground corn and soybeans contributed an additional 170 Mg/kg. Therefore, Diets A, B, C, D, and E contained approximately 370, 510, 650, 1140, and 1910 (Xg biotin/kg diet, respectively. The National Research Council (NRC, 1977) biotin requirement for broiler chicks is 150 jug/kg. Each of the five diets was fed ad libitum to duplicate groups of 25 male Hubbard X Hubbard chicks throughout the 7-week growing period. Birds were raised on a litter floor with .15 m 2 (1.6 ft 2 ) per bird. All birds were slaughtered, scalded (57 C for 110 sec), defeathered, and eviscerated in the poultry processing plant at The Pennsylvania State University. Prior to slaughter, live weights were recorded on all birds. After scalding and defeathering, all carcasses were carefully examined for the presence of deformed legs. Carcasses were also weighed after evisceration, just prior to entering the immersion chill tank (nonagitated ice water for 1 hr), and after chilling, to determine moisture pick-up during chilling. Carcasses were stored in crushed ice in

a 5 C cooler for about 18 hr before being cooked and evaluated. Seven chickens from each of the 10 groups (5 diets X 2 replications) were heated in ovens (163 C) to an internal temperature of 80 C (176 F). Birds were weighed before and after cooking to determine cooking loss and also total loss, i.e., from live weight to cooked weight. After cooking, birds were removed from ovens, cooled for 15 to 20 min, and deboned. Uniform portions of breast (pectoralis major) and thigh (biceps femoris) muscles were then presented to a 12-member trained sensory panel for flavor and tenderness evaluation. Multiple comparison tests were conducted using meat from Diet A (control) birds as a reference sample. The color of breast skin and breast muscle of 5 birds from each group was evaluated with a Hunterlab Tristimulus Colorimter, Model 25L-9. The Hunter L, a,b scale was used, in which " L " measures lightness, "a" measures redness when plus and greenness when minus, and " b " measures yellowness when plus and blueness when minus. The color of raw breast skin was measured along the middle feather tract of the left side of the breast; the color of the raw breast muscle was then measured in a similar position after the skin had been peeled back. Moisture, fat, protein, and ash were determined on raw samples of breast meat and thigh meat from 4 birds of each diet. The general linear models program of the Statistical Analysis System (SAS) computer

TABLE 2. Liveweight, feed conversion, mortality, and deformed legs for broilers fed diets containing dried egg1

Diet

A. B. C. D.

Liveweight

Control, no egg 10% Dried egg 20% Dried egg 10% Dried egg, biotin enriched E. 20% Dried egg, biotin enriched

Feed conversion

Deformed legs2

(g)

(g feed/g grain)

2089 a 1976 a 1224 b

2.23 2.17 2.29

8 6 14

9 23 58

1908 a

2.11

8

17

a

2.02

8

9

1861

a' b Means in a column with different letters differ significantly (P<.01). ' Fifty male broilers (2 X 25/pen) started on each diet. 2

Mortality

A subjective evaluation made during processing after feather removal.

1943

DRIED EGG IN BROILER DIETS package was used to conduct analyses of variance. Differences among cell means were determined using Duncan's multiple range test.

RESULTS AND DISCUSSION The largest broilers at the end of the 7-week growing period were those on the control diet that contained no eggs (Table 2). The next largest group was those on diets containing 10% dried egg, followed by birds on 20% dried egg. However, there were no statistical differences in weight among birds on the five diets except those on Diet C (20% standard egg); these birds were significantly (P<.01) smaller, weighing 35 to 40% less than all other birds. The poorest feed conversion (2.29), the highest mortality (14%), and the greatest incidence of deformed legs (58%) were also observed for birds on Diet C. This is not unexpected, in light of the calculations exhibited in Table 3, because Diet C is deficient in available biotin. Poor growth and deformed legs in chickens can be caused by biotin deficiencies in the diet (Scott et al, 1982). The biotin in Diet C, estimated at 650 /Jg/kg, could have been bound by avidin and biotin-binding protein (BBP) of yolk; both proteins are known to bind available biotin (White and Hughes, 1981). The other four diets were nearly equal to or exceeded the

NRC (1977) requirements for chicks of 150 jug biotin/kg diet. Birds fed Diet D, 10% dried egg with biotin enrichment, showed no benefits over birds fed Diet B, 10% dried egg without enrichment. Diets C and E contained 20% dried egg; broilers fed Diet E were significantly (P<.01) heavier, had lower mortality, and had fewer deformed legs than birds on Diet C. The only difference in the two diets was that Diet E was biotin enriched. These results indicate that broilers can utilize 10% dried egg in a diet without developing problems; however, if fed as 20% of the diet, biotin enrichment is essential. These results tend to support the conclusions of Wehr et al. (1980) that spray-dried eggs are insufficiently heated to inactivate avidin. Avidin, and especially the avidin-biotin complex, are relatively stable in the presence of heat. Donovan and Ross (1973) reported that avidin is inactivated in an endothermic transition at 85 C, whereas a temperature of 132 C is required for a similar transition with the avidin-biotin complex. The BBP found in yolk also denatures at 85 C (White et al., 1976). As expected, based on the liveweight data, weights of the Diet C birds taken during processing or cooking were significantly (P<.01) lower than corresponding weights of birds on the other diets. However, yield data, based on

TABLE 3. Calculated values for biotin, biotin binding protein (BBP), and avidin in broiler diets

Diet

Control, no egg 10% Dried egg 20% Dried egg 10% Dried egg, biotin enriched 20% Dried egg, biotin enriched

Biotin

BBP + avidin2

Available biotin 3

(/ig/kg)

(units/kg)

(Mg/kg)

370 510 650

0 370 740

370 140 0

1140

370

770

1910

740

1170

1 Each diet contains 370 jug biotin/kg, provided by the vitamin mix (200 /ug) and the ground corn and soybeans (170 tig). In addition, the nonenriched dried egg contained 1.4 mg biotin/kg and the biotin-enriched egg contained 7.7 mg biotin/kg. 2 According to White and Hughes (1981), an egg (58.0 g for liquid portion) contains 53.88 units of activity (7.68 units of BBP in the yolk and 46.2 units of avidin in the albumen). One unit of activity is equivalent to 1 jug of bound biotin. Assuming whole liquid eggs are 25% solids, 1 g of dehydrated whole egg will contain 3.7 units of activity. Diets B and D contain 100 g egg/kg of dehydrated egg, or 370 units, and Diets C and E contain 200 g egg/kg, or 740 units. 3 Biotin in diet minus units of activity. National Research Council (1977) requirement for broiler chicks is 150 Mg biotin/kg diet.

MAST ET AL.

1944

TABLE 4. Processing and cooking yields of broilers fed diets containing dried egg

Diet

A. B. C. D.

Control, no egg 10% Dried egg 20% Dried egg 10% Dried egg, biotin enriched E. 20% Dried egg, biotin enriched

Cooking loss3

Total loss4

67.8 a 66.8 a 62.3 a

28.0 a 25.8 a 27.4 a

52.0 a 52.2 a 53.6 a

3.5 a

66.0 a

28.7 a

54.1 a

3.3 a

65.2 a

26.5 a

52.0 a

Eviscerated weight

Chiller H2 O uptake 1

Ready-to-cook yield2

(g) 1373 a 1282 a 743b

2.8 a 3.2* 3.7 a

1221 a 1182 a

\'K)

ab ' Means in a column with different letters differ significantly (P<.01). 1

(Chill weight — eviscerated weight/eviscerated weight)100.

2

(Chill weight/live weight) 100.

3 4

(Precook weight — postcook weight/precook weight) 100. [1 — (postcook weight/live weight)] 100.

percentages, were not significantly different for birds on any of the five diets (Table 4). Meat from broilers fed the control diet had higher fat and lower moisture content than birds on the egg diets (Table 5). This difference (P<.05) was particularly evident between birds on the control diet and those on the 20% standard egg diet. Only minimal differences were observed in the protein content among the birds on the five diets with the exception of the lower protein content of breast meat from birds on Diet C. Except for thigh meat from birds on Diet C, breast and thigh meat from broilers fed the egg diets received flavor ratings equal to or slightly higher than meat from the control broilers; however, no significant differences were ob-

served among any of the flavor scores (Table 6). A different trend was observed for the tenderness scores, where meat from the control birds was, in general, slightly more tender than other meat. These differences were more accentuated, and in some cases significant (P<.05), for the thigh meat. These differences may partially be explained by the differences in fat content observed in Table 5, i.e., higher levels of fat in both breast and thigh meat for the control birds correspond with the most tender meat. The color of breast skin and breast meat was recorded as L (lightness), af_ (redness), and bj^ (yellowness) values. No differences were observed for the breast skin color. The scalding conditions used, i.e., 57 C for 110 sec, were

TABLE 5. Proximate composition of meat from broilers fed diets containing dried egg Moisture

Fat

Ash

Protein

Diet

Breast

Thigh

A. B. C. D.

75.lc 75.2 b c 78.5 a

73.6 d 75.3 C 78.2 a

1.2a 7ab .5b

7.7 a 5.5b 3.4C

76.0°c

76.3 b

.9ab

4.8 b

22.0 a

18.7 a

1.0a

,9 a

76.3 b

75.9bc

.6b

5.7 b

22.7 a

18.4 a

1.0a

.9 a

Control, no egg 10% Dried egg 20% Dried egg 10% Dried egg, biotin enriched E. 20% Dried egg, biotin enriched

Breast

Thigh (">)

Breast

Thigh

Breast

Thigh

22.4 a 22.8 a 20.3b

18.1 a 19.0 a 18.7 a

l.la 1.0a 1.0a

1.0a 1.0* ,8b

' Means in a column with different letters differ significantly (P<.05).

DRIED EGG IN BROILER DIETS

1945

TABLE 6. Sensory evaluation of meat from broilers fed diets containing dried egg. Multiple comparison test used' Flavor

Tenderness

Diet

Breast

Thigh

Breast

Thigh

A. B. C. D.

5.0 a 5.8 a 5.5 a

5.0 a 5.4 a 4.8 a

5.0 a 4.7 a 5.2 a

5.0 a 4.8 a 4.ot>c

5.3 a

5.3 a

4.4 a

3.7C

5.3 a

5.3 a

4.9 a

4.7ab

Control, no egg 10% Dried egg 20% Dried egg 10% Dried egg, biotin enriched E. 20% Dried egg, biotin enriched

' ' Means in a column with different letters differ significantly (P<.05). 1

A value of 5.0 indicates equality to a control. A value higher than 5.0 indicates better flavor or more tender than the control; below 5.0 indicates inferior flavor or less tender than the control. Meat from birds on Diet A used as control.

sufficient to remove the outer layer of skin, thereby removing much of the yellowness. All the birds on egg diets did have slightly higher, but not significant (P<.05), b L values. The b L values for breast muscle of broilers on egg diets were higher than the control birds (8.4 for control birds; > 9.4 for all birds on egg diets). The naturally occurring pigments in chicken egg yolk are mainly xanthophylls, lutein, and zeaxanthin; very little )3-carotene and crypotoxanthin are present (Stadelman and Cotterill, 1977). The color of yellow-skin chicken is also due to xanthophylls (North, 1979). Therefore, although differences were usually not significant, it is not surprising that broilers fed dried whole eggs tended to have yellower skin and meat than birds not fed egg. Results of this study indicate that at least 10% dried whole egg can be incorporated in broiler diets without adverse effects on performance, composition, or meat quality. When biotin-enriched eggs were used, a diet with 20% dried whole egg is acceptable. Therefore, broiler diets may be an acceptable outlet for a large volume of inedible eggs, such as leakers. In this study, broilers on the 10% egg diets consumed 415 g of spray-dried whole egg or the equivalent of about 30 shell eggs; this number increased to 40 eggs for broilers on 20% standard egg diet and 53 eggs for broilers on the 20% biotin enriched egg diet. No considerations for the economic aspects of feeding dried eggs were included in this study. Because spray drying is an expensive process, this may limit the feasibility of incorporating inedible eggs in the dry form into broiler diets.

REFERENCES Donovan, J. W., and K. D. Ross, 1973. Biochemistry 12:512. (From Green, N. M., 1975. Avidin. Adv. Prot. Chem. 29:85-133). Green, N. M., 1975. Avidin. Adv. Prot. Chem. 29: 85-133. Hamilton, R.M.G., 1982. Methods and factors that affect the measurement of egg shell quality. Poultry Sci. 61:2022-2039. National Research Council, 1977. Nutrient Requirements of Poultry. 2nd ed. Nat. Acad. Sci., Washington, DC. North, M. O., 1979. Broiler skin color: keeping it uniform. Broiler Ind. 42(9):70, 74, 76. Oldfield, J. E., and J. Adair, 1981. Data sheet supplied by American Dehydrated Foods, Springfield, MO. Roland, D. A., Sr., 1977. The extent of uncollected eggs due to inadequate shell. Poultry Sci. 56: 1517-1521. . Scott, M. L., M. C. Nesheim, and R. J. Young, 1982. Nutrition of the Chicken. M. L. Scott and Assoc, Ithaca, NY. Stadelman, W. J., and O. J. Cotterill, 1977. Egg Science and Technology. 2nd ed. Avi Publ. Co., Westport, CT. US Department of Agriculture, 1983. Egg grading manual. Agric. Handbook No. 75, rev. April 1983. Agric. Marketing Serv. Washburn, K. W., 1982. Incidence, cause, and prevention of egg shell breakage in commercial production. Poultry Sci. 61:2005-2012. Wehr, N. B., J. Adair, and J. E. Oldfield, 1980. Biotin deficiency in mink fed spray-dried eggs. J. Anim. Sci. 50:877-885. White, H. B., B. A. Dennison, M. A. Della-Fera, C. J. Whitney, J. C. McGuire, H. W. Meslar, and P. H. Sammelwitz, 1976. Biotin-binding protein from egg yolk: assay and relationship to egg white avidin. Biochem. J. 157:395-400. White, H. B., and A. R. Hughes, 1981. Biotin-binding proteins in chicken eggs and the biotin requirements of chicken embryos. Poultry Sci. 60: 1454-1457.