81998Applied Poultry Science. Inc
BROILER
CHICKS HATCHED FROM EGG
WEIGHT EXTREMES
AND DIVERSE
BREEDER
STRAINS'
S. L VIEIRA and E. T.M O W , JR?
Depamnent of Poultry Science and Alabama Agricultural Experiment Station,
Auburn University,AL 36849-5416
Phone: (334) 844-2617
F M : (334) W 2 6 4 1
E-mail: emoran @acesag.aubum.edu
Primarv Audience: Hatcherv Personnel. Nutritionists
at decreasing body fat of broilers, but yolk
DESCRIPTION
OF PROBLEM
formation by the breeder hen may also deWeight of the egg is known to correlate
with weight of the chick at hatch and influence
subsequent live performance [l, 21. Amount
and composition of yolk is known to influence
the chick's post-emergent yolk sac nutrient
reserves. Yolk as a proportion of the egg increases as hens age, but decreases from heavy
to light eggs with hens of the same age [3,4,5].
Selectionfor leannessbased on circulatingvery
low density lipoproteins (VLDL)is effective
1
2
crease [6].
Information on eggs produced by genetically diverse broiler breeder hens is sparse. The
present experiment examined the composition
of eggs and chicksfrom four commercialsources
and the extremes in weight from each strain.
Measurements performed extended beyond
yields of major components to include proximate, amino acid, and mineral compositions.
Alabama Agricultural Experiment Station Journal Series Number 12-985918.
To whom correspondence should be addressed
Research Report
393
VIEIRA and M O W , JR.
sampled after hatching and killed by cervical
MATERIALS
AND METHODSdislocation. Chick carcasses without yolk sacs
Eggs were obtained from breeder flocks
of four different broiler strains having varied
age (A, 36 wk; B, 40 wk; C, 42 wk; D, 45 wk).
Breeders were from commercial flocks, and
management and feed employed are unknown. Sample size was 720 eggs from each
source. These were individually weighed,
and eggs representing the top and the bottom
thirds of each population were categorized as
“heavy”and “light,”respectively. Thirty eggs
were randomly sampled from each strain and
category, then yolk, albumen, and shell (with
membrane) were separated and weighed.
Egg parts were randomly pooled, respective
of source, to attain five replicate samples, then
pooled replicates were lyophilized, ground,
and dried for 18 hr at 60°C to obtain DM
content. Subsamples were analyzed for CP
(kjeldahl), total lipid (diethyl ether extraction
by Goldfish), and ash (24 hr at 600°C).
Amino acid content was done commercially
[“I.Mineral analyses were performed on the
ash solubilized in 6 N HC1 and diluted with
distilled water to accommodate inductively
coupled plasma spectroscopy [8].
Remaining eggs were incubated at the
Auburn University farm hatchery following
established Drocedures. Fifteen chicks from
and yolk sacs with contents were individually
weighed, then parts respective of source were
pooled into one group which was lyophilized
and analyzed as with egg components.
Egg, carcass, and yolk sac amounts and
their proximate data were statistically analyzed using an ANOVA with strain and egg
weight category in a factorial arrangement of
a completely randomized design. The GLM
procedure of SAS was used [9]. Amino acids
in yolk sacs and mineral data were based on
limited samples, and statistical analyses were
not conducted.
RESULTS
AND DISCUSSION
Flock age with hens providing eggs for
each of the strains in the present experiment
varied between 36 and 45 wk. Although a certain amount of confounding from age in the
comparisons among strains can be expected,
genetic background will likelyprevail given the
10-wk maximum difference in age. Although
Strain B was of intermediate age between the
oldest and youngest flocks, its average egg
weight was the greatest (Table 1).Strain B also
had the most yolk and least albumen as a pro-
EGG
YOLK
ALBUMEN
SHELL
***
.**
***
.**
A (36wk)
B (40 wk)
57.9
31.6b
56.y
11.4ab
63.1a
33.3a
54.9b
11.4ab
C (42 wk)
D (45 wk)
SEM‘
61Ab
32.4b
56.1a
ll.lb
62.4ab
31.6b
56.4a
11.6a
0.25
NS
CONTRAST
SI.RAINB
EGG^
H e a v (HI
Light (L)
SEM‘
0.33
0.25
0.27
***
**.
*.*
65.3
31.7
56.6
11.4
57.1
32.8
55.4
11.4
0.23
0.18
0.19
0.18
JAPR
EGG WEIGHT A N D STRAIN
394
Defining heavy and light eggs as being
derived from the upper and lower thirds of one
day's collectionwith each strain provided consistent relative extremes in weight. Such extremes for any one age flock are similar to the
extremes provided by the averages from very
young and old breeder flocks, but relative
amounts of yolk and albumen are reversed.
l)+zilly, light eggs from any one age flock
have the advantage in yolk at the expense of
albumen. In the present experiment, the heavy
and hght eggs from all strains followed this
expectation to the same extent, even though
differences in their average weights and contents of yolk and albumen were apparent.
DM contents of yolk and albumen were
similar among strains and between extremes
in egg weight (Table 2). For some reason, DM
of shells, which included the membranes and
adhering albumen, was low for Strain B. Subsequent analyses of yolk and albumen, as well
as on resulting yolk sac and chick carcass after
egg incubation, were conducted to ascertain
whether egg differences would be reflected
with the chick.
Alterations in the proximate compositions of yolk and albumen DM attributable to
strain and egg weight were largely independent of each other (Table 2). Diethyl ether
extract (DEE) content varied among strains
with yolk, whereas CP dominated variability
with albumen. DM in both yolk and albumen
had a greater proportion of CP for heavy eggs
of all strains than for light. These differences
were not expressed to the same extent between
the extremes in egg weight with each of the
strains.
TABLE 2. Proximate compositions of components from heavy and light eggs of different strain breeder flocksA
*Values represent six replicate measurements each with fwe yolks, albumens and shells pooled, res ctive of egg
weight and strain. Data are given as contrasts of main factors in the absence of significant interaction &.OS),
except
where footnoted.
BDiethylether extract.
%our commercial source flocks (wk of age).
DStrain X Egg (P < .Ol): AH = 31.0; AL = 29.9; BH = 31.6; BL = 31.6; CH = 30.7 CL = 30.9; DH = 31.6; DL = 29.2;
SEM = 0.39.
EStrain X Egg (Pc.01): AH=51.3; AL=59.6; BH=60.6; BL=61.0; CH=59.2; CL=60.4; DH=53.6; DL=59.0;
SEM = 0.98.
FStrain X Egg (P < .Ol): AH = 825; AL= 77.s; BH = 80.9; BL= 7.9; CH = 80A; CL = 77.9;DH = 78.4;DL = 78.3;
SEM = 0.54.
GStrain X Egg(P<.OOl): AH=O.43; AL=0.20; BH=0.31; BL=0.65; CH=0.09; CL=0.23; DH=1.15; DL=0.18;
SEM = 0.12.
"Standard error of the mean had 40 df and was adjusted for each contrast.
'Heavy and light correspond to the top and bottom thirds of population by weight, respective of strain.
'P e .OS: **P< .01; *+*P< .OOl; NS = Non-significant (P > .OS).
Research Report
VIEIRA and M O W , JR.
395
Weight and composition of chicks at
emergence canbe expected to reflect egg composition. Carcasses, after removal of yolk sac,
differed in weght parallel to differences in egg
weight among strains, but the extent of expression between the heavy and light categories
varied (Table 3). Yolk sacs from each of the
strains were similar in amount and as a proportion of the whole chick; however, yolk sacs
from chicks derived from heavy eggs were
greater in weight and proportion than those
from eggs categorized as light.
Although amount of the chick carcass
differed substantially among strains and between weight categories, relative composition
showed little variation (Table 4). On the
other hand, composition of the yolk sacvaried
among strains and between weight categories,
particularly in DEE and ash. These differ-
ences were not expressed to the same extent
among the strains as they had been with the
yolk in eggs prior to incubation.
Further analyses of amino acids in the CP
and minerals in the ash were conducted to
ascertain potential differences among strain
sources and between egg weight categories.
Although differences existed in relative amino
acid contents with CP in egg yolks (Table 5)
and chick carcasses (Table 6) which could be
attributed to strain and egg weight category,
they appeared to be minimal and interpretation is left to the reader. Limited sample size
did not permit replicate amino acid analyses
of yolk sacs nor of minerals in ash from egg
yolk, albumen, chick carcasses, and yolk sacs.
In the absence of data from samples, this information is provided from the literature at
large (Tables 7,8, and 9).
TABLE 3. Carcass and yolk sac with chicks after incubation of heavy and light eggs obtained from different
strain breeder flocksA
CONTRAST
SI.RAINB
CARCASS
YOLK SAC
Weight, g
Weight, g
%Whole Chick
***C
NS
NS
10.3
A (36wk)
B (40 wk)
39.4b
45
42.1a
4.6
9.9
C (42 wk)
42.0a
5.2
11.0
D (45 wk)
43.2a
5.2
10.7
SEM~
059
***C
0.26
***
***
Heavy (HI
445
5.6
11.2
Light (L)
SEM~
38.6
EGG^
0.42
0.50
4.0
9.4
0.18
0.36
BFourcommercial source flocks (wk of age).
'Strain X Egg (Pc.05); AH=42.0; AL=36.6; BH=46.2; BL=37.4; CH=44.0; c1=39.3; DH=45.4; DL=41.1;
SEM = 0.90.
DStandard error of the mean had 112 df and was adjusted for each contrast.
%cavy and light correspond to the top and bottom thirds of egg population by weight, respective of strain.
***P<.001;NS=Non-significant (P>.OS).
JAPR
EGG WEIGHT A N D STRAIN
3%
TABLE 4. Proximate composition of carcasses and yolk sacs of chicks using heavy and light eggs obtained
from different strain breeder flocksA
*DM values are the average of 15 carcasses and yolk sacs respective of strain and e weight. CP, DEE, and
ash were the average of six replicate measurements on carcasses and yolk sacs poolefigrespective of strain and
eip weight. Data are given as contrasts of main factors in the absence of significant interactions (P > .OS), except
w ere footnoted.
BDiethyl ether extract.
'FOW
commercial source flocks (wk of age).
'Strain X Egg (P e .02): AH = 49.9; AL = 45.8; BH = 47.2; BL = 52.1; CH = 47.2; CL = 55.0; DH = 48.2; DL = 48.2
SEM = 2.91.
EStrain X Egg (P .001): AH = 29.2; AL = 35.9; BH = 34.6;BL = 36.0; CH = 31.8; CL = 37.3; DH = 35.2; DL = 38.6;
SEM = 0.39.
'Strain
X
Egg (P < .001): AH =4.4; AL=5.1; BH =4.3; BL= 5.1; CH =4.7; CL =4.6; DH = 3.9;DL=5.0; SEM = 0.01.
GStandarderror of the mean had 40 df and is adjusted for each contrast.
HHeavyand light correspond to the top and bottom thirds of egg population by weight.
*P<.O5; "Pe.01; ***Pe.001; NS=Non-significant (P>.O5).
Research Report
VIEIFU and M O W , JR.
397
398
EGG WEIGHT AND STRAIN
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400
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Research Report
VIEIRA and M O W , JR.
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JAPR
EGG WEIGHT AND STRAIN
402
CONCLUSIONS
AND APPLICATIONS
1. Proportions of yolk and albumen in eggs from broiler breeders are affected by egg weight
in any one population, as well as by strain. Proximate compositions are also affected by
extremes in weight, and differences may be expressed to varying extent among strains.
2. Chick weight at hatching is known to be a reflection of the egg weight. Chicks from various
strains reflect the egg in weight, but have similar carcass compositions. Yolk sac, on the
other hand, has similar proportions to the chick but varies in composition.
3. Overall results do not suggest differences in relative nutrient needs at placement among
chicks from extremes in egg weights nor diverse strains that might be accommodated in the
first feed.
REFERENCES
AND NOTES
1. S h a m a n y , M.M., 1987, Hatching wei t in relation to egg weight in domestic birds. World’s &&Sei.
J. 43107-115.
2. Wilson, H.R, 1991. Interrelationships of e sue,
chick size, posthatching growth, and hatchability. gorld’s
PoultT SCI.J. 475-20.
3. Varadarqjulu, P. and F.E Cunningham, 1972.
A study of selected characteristics of hen’s egg yolk.
fowl. 11. Egg weight-chick weight ratios. Poultry Sci.
29595-604.
6. Whitehead, C.C., 1988. Selection for leanness
in broilers using plasma li protein concentration as
selection criterion. Pages K-57 in: Leanness in DOmestic Birds. B. Leclercq and C.C. Whitehead, eds.
Buttemrths, London, England.
7.Degussa Corporation, Allendale, NJ 07401.
3. Influence of breed, strain, and age of birds. Poultry Sci.
51:1327-1331.
8. Soils Laboratory, Auburn University, Auburn, AL
36830.
4. Marion, W.W., A.W. Nordskog, H.S. Tolman, and
R H . Forsythe, 1964. Egg composition as influenced by
breeding, egg sue, age, and season. Poultry Sci. 43:225264.
9. SAS Institute, 1998. SAS/STAT User’s Guide.
Release 6.03 Edition. SAS Institute, Inc., Caly, NC.
5. Wiky, W.H., 1950. The influence of egg weight on
the pre-hatching and post-hatching growth rate in the
ACKNOWLEDGEMENT
The authorswish to thank Cynthia Llames of Degussa
Corp. for her assistance.