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Relationship Between Hatch Weight as a Percentage of Egg Weight and Feed Conversion Ratio in Broiler Chicks
CHICK EDEMA DISEASE
Higginbotham, G. R., A. Huang, D. Firestone, M. J. Verrett, J. Ress and A. D. Campbell, 1968. Chemical and toxicological evaluations of isolated and synthetic chloro derivatives of dibenzo^>-dioxin. Nature, 220: 702-703. Kimmig, J., and K. H. Schulz, 1957. Occupational chloracne caused by aromatic cyclic ethers. Dermatologica, 115: 540-546. McLaughlin, J., Jr., J. P . Marliac, M. J. Verrett, M. K. Mutchler and O. G. Fitzhugh, 1963. The injection of chemicals into the yolk sac of fertile eggs prior to incubation as a toxicity test. Toxicol. Appl. Pharmacol. 5: 760-771. Schmittle, S. C , H. M. Edwards and D. Morris, 1958. A disorder of chickens probably due to a toxic feed—Preliminary report. J. Am. Vet. Med. Assoc. 132: 216-219. Schulz, K. H., 1968. Clinical picture and etiology of chloracne. Arbeitsmed. Soz.-Arbeitshyg. 3 : 2 5 29. Wootton, J. C , and W. L. Courchene, 1964. A contribution to the knowledge of the structure of two hydropericardium-producing factors from a toxic fat. J. Agr. Food Chem. 12: 94-98.
Relationship Between Hatch Weight as a Percentage of Egg Weight and Feed Conversion Ratio in Broiler Chicks R. A. GTJILL AND K . W. W A S H B U R N
Department of Poultry Science, University of Georgia, A thens, Georgia 30602 (Received for publication December 4, 1972) ABSTRACT Three trials were conducted comparing hatch weight as a percentage of egg weight with feed conversion of five selected lines (selected for low or high feed conversion) within two populations (broiler and randombred) of chickens. In each trial all eggs were weighed and divided into groups of 1 gram intervals within each line prior to incubation. At hatching all chicks were weighed, banded and their percent hatch weight determined. There were no differences in percent hatch weight of the lines that differed in feed conversion ratio in the broiler strains from 4-8 weeks of age or the randombred strains from 1-9 weeks of age. There was no correlation between percent hatch weight and feed conversion ratio within any of the lines and none at different ages. The percent hatch weight of the randombred strain ranged from 56-72% while that for the broiler strain ranged from 60-76%. The coefficient of variation was 4 % in both strains. POULTHY SCIENCE 52:1641-1646,1973
I
N
t h e e a r l i e r p h a s e s of r e s e a r c h
con-
cerning selection for g r o w t h r a t e t h e
p o s s i b i l i t y of u t i l i z i n g e g g w e i g h t o r c h i c k w e i g h t a s a n i n d e x of g r o w t h r a t e w a s intensively
studied.
Halbersleben
and
Mussehl (1922) found no difference in 35day weight of chicks hatched from large or small eggs. T h e average percent h a t c h weight of all chicks from either large or small eggs was 6 4 % of t h e unincubated
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on December 1, 2014
Flick, D. F., V. A. Childs and R. G. O'Dell, 1966. Studies of the chick edema disease. 4. Age sensitivity, recovery and mortality. Poultry Sci. 45: 630-636. Flick, D. F., D. Firestone and J. P. Marliac, 1965a. Studies of the chick edema disease. 2. Preparation and biological effects of a crystalline chick edema factor concentrate. Poultry Sci. 44: 12141222. Flick, D. F., R. G. O'Dell and V. A. Childs, 1965b. Studies of the chick edema disease. 3. Similarity of symptoms produced by feeding chlorinated biphenyl. Poultry Sci. 44: 1460-1465. Flick, D. F., R. G. O'Dell and V. A. Childs, 1967. Studies of the chick edema disease. 5. Long-term low-level feeding of chick edema factor. Poultry Sci. 46: 186-191. Friedman, L., D. Firestone, W. Horwitz, D. Banes, M. Anstead and G. Shue, 1959. Studies of the chick edema factor. J. Assoc. Offic. Agr. Chemists, 42:129-140. Harman, R. E., G. E. Davis, W. H. Ott, N. G. Brink and F . A. Kuehl, Jr., 1960. The isolation and characterization of the chick edema factor. J. Am. Chem. Soc. 82: 2078-2079.
1641
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R. A. GUILL AND K. W. WASHBURN
which differed drastically in egg size and growth rate. Although egg size and chick size are highly correlated subsequent growth rate is not. However, if differences exist in percent hatch weight of chicks this may indicate a better efficiency of embryonic utilization of the nutrients in the egg. This embryonic difference in efficiency might be correlated with subsequent efficiency. If so, this would provide a valuable tool in selection programs for feed efficiency. The following study was undertaken to determine if percent hatch weight is an indicator of the efficiency of the growing chick. MATERIALS AND METHODS
The hatch weight as a percentage of egg weight was obtained from chicks of lines selected for differences in feed conversion ratio. In developing the lines two different base populations were used: a commercial broiler line and the randombred population described by Hess (1962). Within each population two high and two low feed conversion ratio lines were developed; one selected for feed conversion so that body weight remained constant (compared to controls) over generations, the other selected solely on feed conversion ratio so that body weight was variable over generations. This selection program resulted in five distinct lines within each population; the high conversion ratio—weight constant (HLWK), the high conversion ratio—-weight variable (HLWV), the low conversion ratio—• weight constant (LLWK), the low conversion ratio—weight variable (LLWV) and the non-selected control (C) lines. Selection for feed conversion ratio was based on pounds of feed required to produce one pound of gain to a specified age. In Trial 1, the chicks used were obtained from the Fi feed conversion ratio lines of
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on December 1, 2014
egg. Jull and Quinn (1925) found an average percent hatch weight of 66% from either large or small eggs. There was no significant difference between larger yearling eggs and smaller pullet eggs in the percentage hatch weight of chicks. Upp (1928) found an average percent hatch weight of 68% and concluded that dayold chick weight was an unreliable index of 2, 4 or 12 week weights. He further emphasized that growth rate was independent of egg size and chick size at hatching. Jull and Heywang (1930) reported that chick weight was approximately 68% of the egg weight. Wiley (1950) indicated a slight advantage in body weight for chicks hatched from large eggs, but by 12 weeks they were not different from chicks hatched from small eggs. He indicated a greater feed requirement to produce a pound of gain in body weight for chicks hatched from small eggs than for those hatched from large eggs. Tindell and Morris (1964) found no differences in feed conversion of chicks from four egg weight groups ranging from 18-26 oz./doz. O'Neil (1950) concluded that chicks with the highest percent hatch weight were heavier at 8 weeks of age and more efficient in feed utilization. Wiley (1950) also reported significant differences in feed conversion in favor of birds hatched from larger eggs. Goodwin (1961) concluded that an increase of one ounce per dozen in egg size was associated with .07-.08 pounds of additional weight at nine weeks. Kosin et al. (1952) found that egg size had a positive effect on body weight gain, but variations due to breed and sex precluded a generalization with respect to this relationship. However, Bray and Iton (1962), using 5 strains of chickens differing in body weight, found no difference in percent hatch weight (71%) between strains
1643
HATCH WEIGHT AND FEED CONVERSION
TABLE 1.—Feed conversion, percent hatch weight and correlations between feed conversion and percent hatch weight Trial 2 F 3 of Selected Broiler Strain
Trial 1 Fi of ARB-ACRB
F / C Ratio
% Hatch Wt.
r
F / C Ratio
% Hatch Wt.
r
LLWV
2.42+.02
66 + 0.2
+ .06
2.16+.02
69+0.3
-.07
LLWK
2.43+.02 X2.42*
66 + 0.2 66 m
+ .01 + .03
2.15+ .01 2.15*
68 + 0.3 69 m
-.18 -.12
CONTROL
2.55+.03
66 + 0.3
-.37
2.24+.02
68 + 0.2
+ .20
HLWV
2 . 6 3 + . 02
64+0.3
-.08
2.35+.01
69 + 0.3
-.11
HLWK
2.61 + .03 X2.62b
64 + 0.2 64 m
+ .20 + .08
2.35+.02 2.35*
69 + 0.4 69 -
+ .09 -.01
LL = low line; HL = high line. WV = weight variable; WK = weight constant. Those means with the same superscript were not significantly different at P < .05. F / C Ratio = Feed conversion ratio for 5-9 weeks in Trial 1 and 4-8 weeks in Trial 2. r = correlation between feed conversion ratio and percent hatch weight on a within line basis.
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on December 1, 2014
strains (Trial 2) and the first week for the ARB-ACRB strains (Trial 1). From week 1 to week 5 the ARB-ACRB strains were divided into three-percent hatch weight groups (70 > , 66-69 and 61-65), maintaining separation between the lines and group feed conversion data obtained at weekly intervals. At five weeks of age for the randombred lines in Trial 1 and at four weeks of age for the broiler lines in Trial 2, 96 chicks of each of the five lines (48 c? and 48 9 ) were placed in individual cages for determination of individual feed conversion ratios (This system used is described in detail by Guill and Washburn, 1972). These birds were allowed a three-day adjustment period at which time individual feed conversion data were obtained. All birds and feed were weighed at 2-week intervals to determine the growth rate and feed conversion ratio of the five lines and to compare the percent hatch weight of each chick with the feed conversion ratio within lines and between lines at 0-2 weeks on trial, 2-4 weeks on trial and 0-4 weeks on trial. Phenotypic correlations
the randombred population. In Trial 2, the chicks were obtained from the F 3 feed conversion ratio lines of the commercial broiler line. In Trial 3 both the Fi random-bred chicks and the F3 broiler line chicks were used. In each trial all eggs were weighed and divided into groups of 1 g. intervals within each line prior to incubation. In Trial 1 the eggs were incubated in a Jamesway Model 252 forced draft incubator and transferred to hatching trays at 18 days. In Trial 2 the eggs were incubated in a Petersime Model S26I forced draft incubator and transferred to a Petersime Model S26H hatcher at 18 days. A third trial was conducted in which eggs of both the randombred and broiler lines were incubated in the Jamesway Model 252 incubator. At hatching all chicks were weighed, wing banded and the percent weight of chick at hatching to egg weight at setting (percent hatch weight) was determined. The chicks were reared in conventional shavings covered floor pens for the first four weeks for the commercial broiler
1644
R. A. GUILL AND K. W. WASHBURN
TABLE 2.—Correlations between feed conversion and percent hatch weight at different ages Trial 2 F 3 of Selected Broiler Strain
Trial 1 F! of ARB-ACRB Age
Correlation
Age
Correlation
5-7 wk 7-9 wk 5-9 wk
+ .02 -.06 -.02
4-6 wk 6 8wk 4-8 wk
+ .15 + .02
-.06
RESULTS AND DISCUSSION The mean feed conversion ratios, the mean percent hatch weight and their correlation for each of the five lines of the random breeds (Trial 1) and commercial broilers (Trial 2) are presented in Table 1. Although there was a significant difference in feed conversion ratios between selected lines and between strains the
TABLE 3.—Mean feed conversion ratios (5-9 weeks, Trial 1 and 4-8 weeks, Trial 2) for each percent hatch weight group Trial 2 F3 of Selected Broiler Strain
Trial 1 Fi of ARB-ACRB Feed Conversion Percent Hatch Wt.
Ratio
72(3) 71 (14) 70 (21) 69 (30) 68 (33) 67 (59) 66 (49) 65 (47) 64 (35) 63 (42) 62 (17) 61(11) 60 (12) 56-59 (12) X=66 C.V. 4.0
2.50 2.54 2.54 2.47 2.57 2.52 2.51 2.50 2.51 2.49 2.52 2.56 2.63 2.54 2.52 9.7
( ) number of individuals. C.V. = coefficient of variation.
Deviation From Mean + 2 +2 +2 -5 +5 0 -1 -2 -1 -3 0 +4 + 11
Feed Conversion Percent Hatch Wt.
74-76 (8) 73 (12) 72 (24) 71 (40) 70 (52) 69(46) 68 (58) 67 (52) 66 (30) 65 (28) 64(8) 63(7) 60-62 (9) 68 4.0
Ratio
2.25 2.25 2.25 2.32 2.27 2.22 2.25 2.22 2.24 2.31 2.18 2.27 2.20 2.25 7.5
Deviation From Mean 0 0 0 +7 +2 -3 0 -3 -1 +6 -7 +2 -5
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between percent hatch weight and feed conversion ratios were calculated within strains.
differences between these lines in percent hatch weight were negligible. Furthermore, the correlations between individual feed conversion ratios and percent hatch weight calculated within lines were small and non-significant for both the randombred and the selected broiler lines. Wiley (1950) indicated a greater feed requirement in chicks hatched from small eggs and Kosin et al. (1952) found egg size had a positive effect on body weight gain. However, the results of this study show no relationship between feed conversion or growth rate and percent hatch weight. The LLWV grew at a slightly faster rate, while the HLWV grew at a slightly slower rate than the LLWK, HLWK or C lines, yet their percent hatch weight was not significantly different. The correlations between feed conversion and percent hatch weight for all birds studied are shown in Table 2 with the two age periods separate. There was no indi-
1645
HATCH WEIGHT AND FEED CONVERSION
Although there was no effect of percent hatch on 4 to 8 week feed conversion, a relationship that existed at an early age may be obscured at four weeks of age. Although it was not possible to measure individual feed conversion from 1 to 28 TABLE 4.—Mean percent hatch weight of all chicks hatched
Fxof ARB-ACRB Trial 1 Trial 2 Trial 3 Hatch 1 Hatch 2
65%
F 3 of Selected Broiler Strain
— 69%
67% 67%
67% 67%
TABLE 5.—Mean feed conversion ratios and percent hatch weight for males and females of the five selected lines of ARB-A CRB from 1 to 5 weeks Percent Hatch Wt. IX WV
LLWK
HLWV
HLWK
Contrc
Feed Conversion Ratio 70 > 66-69 61-65
1.63 1.63 1.70
1.63 1.63 1.73
1.72 1.70 1.67
1.72 1.74 1.65
1.60 1.72 1.64
9 70 > 66-69 61-65
1.61 1.85 1.81
1.61 1.72 1.67
1.76 2.01 1.77
1.76 1.98 1.71
1.75 1.74 1.87
IX = low line, RX = high line; WV = weight variable, WK = weight constant.
days, pen feed conversions were obtained for each line and three hatch weight groups of the randombred lines. These data are presented in Table 5. There were no significant differences in feed conversion between lines or between hatch weight groups although there was a significant difference between sexes. REFERENCES Bray, D. F., and E. L. Iton, 1962. The effect of egg weight on strain differences in embryonic and post-embryonic growth in the domestic fowl. Brit. Poultry Sci. 3: 175-188. Guill, R. A., and K. W. Washburn, 1972. Cages and feed troughs for individual feed consumption experiments. Poultry Sci. 51: 1047-1048. Goodwin, K., 1961. Effect of hatching egg size and chick size upon subsequent growth rate in chickens. Poultry Sci. 40: 1408. Halbersleben, D. L., and F. E. Mussehl, 1922. Relation of egg weight to chick weight at hatching. Poultry Sci. 1: 143-144. Hess, C. W., 1962. Randombred populations of the southern regional poultry breeding project. Wld's. Poultry Sci. J. 19: 147-152. Jull, M. A., and J. P. Quinn, 1925. The relationship between the weight of eggs and the weight of chicks according to sex. J. Agr. Res. 31: 223-226. Jull, M. A., and B. W. Heywang, 1930. Yolk assimilation during the embryonic development of the chick. Poultry Sci. 9: 393-404. Kosin, I. L., H. Abplanalp, J. Gutierrez and J. S. Carver, 1952. The influence of egg size on subsequent early growth of the chick. Poultry Sci. 31: 247-254. O'Neil, J. B., 1950. Relationship of chick size to egg
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cation of a difference in percent hatch weight between the fast growing highly efficient strain and the slower growing randombreds (Table 1). A comparison of the correlations for the two age-periods in which efficiency was measured shows no changes with age. The percent hatch weight for the ARBACRB ranged from 56 to 72 percent with a median of 66% while for the broiler strain the range was 60 to 76% with a median of 68% (Table 3). The mean for the randombred was lower (65%) than that for the selected broiler strain (69%) suggesting that the selected broiler strain which was more efficient in feed utilization after hatching was also more efficient in embryonic development. However, this comparison was made between eggs hatched in different incubators. When eggs from the randombreds and broiler strains were incubated together (Trial 3) the percent hatch weight was 67% for both strains in each of the two hatches (Table 4). This indicates that the comparisons of percent hatch weight obtained by using different incubators and hatchers could result in erroneous conclusions as to the relationship of hatch weight and feed conversion or growth rate.
1646
R. A. GUILL AND K. W. WASHBURN
size and its effect upon growth and mortality. Poultry Sci. 29: 774. Tindell, D., and D. R. Morris, 1964. The effects of egg weight on subsequent broiler performance. Poultry Sci. 43: 534-539. Upp, C. W., 1928. Egg weight, day old chick weight
and rate of growth in Single Comb Rhode Island Red chicks. Poultry Sci. 7: 151-155. Wiley, W. H., 1950. The influence of egg weight on the pre-hatching and post-hatching growth rate in the fowl. 2. Egg weight-chick weight ratios. Poultry Sci. 29: 595-604.
D. B. BRAGG AND A. I. AKINWANDE Department of Poultry Science, University of British Columbia, Vancouver 8, British Columbia, Canada (Received for publication December 9, 1972) ABSTRACT Six hundred and forty-eight White Leghorn chicks, 408 broiler breeder pullets and 92 Cornish males were utilized in two feeding trials to study the limiting amino acids in wheat protein diets. Results of Trial 1 with White Leghorn chicks indicate that rate of growth was depressed by reducing dietary protein from 20 to 15%. Body weight was not significantly improved by the addition of methionine, leucine, threonine, arginine, valine and isoleucine in various combinations to a wheat-lysine diet. However, treatments that included threonine consistently resulted in slightly heavier birds at four weeks of age than the wheatlysine diet. Results with broiler breeder pullets showed that a 15% protein wheat-lysine diet supported better growth than a wheat-soya diet. Supplemental dietary threonine in the wheat-lysine diet significantly improved growth. Also, diets fortified with threonine and valine improved the growth rate supported by the wheat-lysine diet. Results with Cornish males indicate that wheat protein is limiting in lysine, threonine and valine. A marked response was observed by the addition of both threonine and valine to the wheat-lysine diet. POULTRY SCIENCE 52: 1646-1651, 1973
INTRODUCTION
T
HE value of wheat protein as the sole source of dietary protein in chick diets was first demonstrated by Jeppsen and Graw (1948). Wheat protein was concentrated by removing starch from whole wheat and used to supply protein in a balanced chick diet. These workers concluded from results of the chick study that arginine, leucine, methionine, and tryptophan were adequate to support chick growth. However, lysine supplementation enhanced growth of chicks fed the wheat protein diet. Results of a recent study showed that high protein wheat, used as the only source of dietary protein, failed to support a rate of growth adequate for normal development of White Leghorn chicks
(Bragg et al., 1971). The addition of lysine to the wheat protein diet maintained growth equal to that of a wheat-soya diet containing equal dietary protein. It was also demonstrated that wheat supplied less than 50% of the lysine required for normal growth. Strain and Piloski (1972) compared the nutritional value of various wheat and barley samples by using chicks from three to ten weeks of age. Results indicated that no difference existed among samples of barley or samples of wheat, however, the barley samples support better growth than wheat. These workers suggested that wheat provided more energy than barley. The higher energy would account for the poorer performance in wheat than in barley. Since lysine was the most limiting
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The Nutritional Value of Wheat Protein for Early Growth of Layer and Broiler Breeder Pullets
Higginbotham, G. R., A. Huang, D. Firestone, M. J. Verrett, J. Ress and A. D. Campbell, 1968. Chemical and toxicological evaluations of isolated and synthetic chloro derivatives of dibenzo^>-dioxin. Nature, 220: 702-703. Kimmig, J., and K. H. Schulz, 1957. Occupational chloracne caused by aromatic cyclic ethers. Dermatologica, 115: 540-546. McLaughlin, J., Jr., J. P . Marliac, M. J. Verrett, M. K. Mutchler and O. G. Fitzhugh, 1963. The injection of chemicals into the yolk sac of fertile eggs prior to incubation as a toxicity test. Toxicol. Appl. Pharmacol. 5: 760-771. Schmittle, S. C , H. M. Edwards and D. Morris, 1958. A disorder of chickens probably due to a toxic feed—Preliminary report. J. Am. Vet. Med. Assoc. 132: 216-219. Schulz, K. H., 1968. Clinical picture and etiology of chloracne. Arbeitsmed. Soz.-Arbeitshyg. 3 : 2 5 29. Wootton, J. C , and W. L. Courchene, 1964. A contribution to the knowledge of the structure of two hydropericardium-producing factors from a toxic fat. J. Agr. Food Chem. 12: 94-98.
Relationship Between Hatch Weight as a Percentage of Egg Weight and Feed Conversion Ratio in Broiler Chicks R. A. GTJILL AND K . W. W A S H B U R N
Department of Poultry Science, University of Georgia, A thens, Georgia 30602 (Received for publication December 4, 1972) ABSTRACT Three trials were conducted comparing hatch weight as a percentage of egg weight with feed conversion of five selected lines (selected for low or high feed conversion) within two populations (broiler and randombred) of chickens. In each trial all eggs were weighed and divided into groups of 1 gram intervals within each line prior to incubation. At hatching all chicks were weighed, banded and their percent hatch weight determined. There were no differences in percent hatch weight of the lines that differed in feed conversion ratio in the broiler strains from 4-8 weeks of age or the randombred strains from 1-9 weeks of age. There was no correlation between percent hatch weight and feed conversion ratio within any of the lines and none at different ages. The percent hatch weight of the randombred strain ranged from 56-72% while that for the broiler strain ranged from 60-76%. The coefficient of variation was 4 % in both strains. POULTHY SCIENCE 52:1641-1646,1973
I
N
t h e e a r l i e r p h a s e s of r e s e a r c h
con-
cerning selection for g r o w t h r a t e t h e
p o s s i b i l i t y of u t i l i z i n g e g g w e i g h t o r c h i c k w e i g h t a s a n i n d e x of g r o w t h r a t e w a s intensively
studied.
Halbersleben
and
Mussehl (1922) found no difference in 35day weight of chicks hatched from large or small eggs. T h e average percent h a t c h weight of all chicks from either large or small eggs was 6 4 % of t h e unincubated
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on December 1, 2014
Flick, D. F., V. A. Childs and R. G. O'Dell, 1966. Studies of the chick edema disease. 4. Age sensitivity, recovery and mortality. Poultry Sci. 45: 630-636. Flick, D. F., D. Firestone and J. P. Marliac, 1965a. Studies of the chick edema disease. 2. Preparation and biological effects of a crystalline chick edema factor concentrate. Poultry Sci. 44: 12141222. Flick, D. F., R. G. O'Dell and V. A. Childs, 1965b. Studies of the chick edema disease. 3. Similarity of symptoms produced by feeding chlorinated biphenyl. Poultry Sci. 44: 1460-1465. Flick, D. F., R. G. O'Dell and V. A. Childs, 1967. Studies of the chick edema disease. 5. Long-term low-level feeding of chick edema factor. Poultry Sci. 46: 186-191. Friedman, L., D. Firestone, W. Horwitz, D. Banes, M. Anstead and G. Shue, 1959. Studies of the chick edema factor. J. Assoc. Offic. Agr. Chemists, 42:129-140. Harman, R. E., G. E. Davis, W. H. Ott, N. G. Brink and F . A. Kuehl, Jr., 1960. The isolation and characterization of the chick edema factor. J. Am. Chem. Soc. 82: 2078-2079.
1641
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R. A. GUILL AND K. W. WASHBURN
which differed drastically in egg size and growth rate. Although egg size and chick size are highly correlated subsequent growth rate is not. However, if differences exist in percent hatch weight of chicks this may indicate a better efficiency of embryonic utilization of the nutrients in the egg. This embryonic difference in efficiency might be correlated with subsequent efficiency. If so, this would provide a valuable tool in selection programs for feed efficiency. The following study was undertaken to determine if percent hatch weight is an indicator of the efficiency of the growing chick. MATERIALS AND METHODS
The hatch weight as a percentage of egg weight was obtained from chicks of lines selected for differences in feed conversion ratio. In developing the lines two different base populations were used: a commercial broiler line and the randombred population described by Hess (1962). Within each population two high and two low feed conversion ratio lines were developed; one selected for feed conversion so that body weight remained constant (compared to controls) over generations, the other selected solely on feed conversion ratio so that body weight was variable over generations. This selection program resulted in five distinct lines within each population; the high conversion ratio—weight constant (HLWK), the high conversion ratio—-weight variable (HLWV), the low conversion ratio—• weight constant (LLWK), the low conversion ratio—weight variable (LLWV) and the non-selected control (C) lines. Selection for feed conversion ratio was based on pounds of feed required to produce one pound of gain to a specified age. In Trial 1, the chicks used were obtained from the Fi feed conversion ratio lines of
Downloaded from http://ps.oxfordjournals.org/ at Columbia University Libraries on December 1, 2014
egg. Jull and Quinn (1925) found an average percent hatch weight of 66% from either large or small eggs. There was no significant difference between larger yearling eggs and smaller pullet eggs in the percentage hatch weight of chicks. Upp (1928) found an average percent hatch weight of 68% and concluded that dayold chick weight was an unreliable index of 2, 4 or 12 week weights. He further emphasized that growth rate was independent of egg size and chick size at hatching. Jull and Heywang (1930) reported that chick weight was approximately 68% of the egg weight. Wiley (1950) indicated a slight advantage in body weight for chicks hatched from large eggs, but by 12 weeks they were not different from chicks hatched from small eggs. He indicated a greater feed requirement to produce a pound of gain in body weight for chicks hatched from small eggs than for those hatched from large eggs. Tindell and Morris (1964) found no differences in feed conversion of chicks from four egg weight groups ranging from 18-26 oz./doz. O'Neil (1950) concluded that chicks with the highest percent hatch weight were heavier at 8 weeks of age and more efficient in feed utilization. Wiley (1950) also reported significant differences in feed conversion in favor of birds hatched from larger eggs. Goodwin (1961) concluded that an increase of one ounce per dozen in egg size was associated with .07-.08 pounds of additional weight at nine weeks. Kosin et al. (1952) found that egg size had a positive effect on body weight gain, but variations due to breed and sex precluded a generalization with respect to this relationship. However, Bray and Iton (1962), using 5 strains of chickens differing in body weight, found no difference in percent hatch weight (71%) between strains
1643
HATCH WEIGHT AND FEED CONVERSION
TABLE 1.—Feed conversion, percent hatch weight and correlations between feed conversion and percent hatch weight Trial 2 F 3 of Selected Broiler Strain
Trial 1 Fi of ARB-ACRB
F / C Ratio
% Hatch Wt.
r
F / C Ratio
% Hatch Wt.
r
LLWV
2.42+.02
66 + 0.2
+ .06
2.16+.02
69+0.3
-.07
LLWK
2.43+.02 X2.42*
66 + 0.2 66 m
+ .01 + .03
2.15+ .01 2.15*
68 + 0.3 69 m
-.18 -.12
CONTROL
2.55+.03
66 + 0.3
-.37
2.24+.02
68 + 0.2
+ .20
HLWV
2 . 6 3 + . 02
64+0.3
-.08
2.35+.01
69 + 0.3
-.11
HLWK
2.61 + .03 X2.62b
64 + 0.2 64 m
+ .20 + .08
2.35+.02 2.35*
69 + 0.4 69 -
+ .09 -.01
LL = low line; HL = high line. WV = weight variable; WK = weight constant. Those means with the same superscript were not significantly different at P < .05. F / C Ratio = Feed conversion ratio for 5-9 weeks in Trial 1 and 4-8 weeks in Trial 2. r = correlation between feed conversion ratio and percent hatch weight on a within line basis.
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strains (Trial 2) and the first week for the ARB-ACRB strains (Trial 1). From week 1 to week 5 the ARB-ACRB strains were divided into three-percent hatch weight groups (70 > , 66-69 and 61-65), maintaining separation between the lines and group feed conversion data obtained at weekly intervals. At five weeks of age for the randombred lines in Trial 1 and at four weeks of age for the broiler lines in Trial 2, 96 chicks of each of the five lines (48 c? and 48 9 ) were placed in individual cages for determination of individual feed conversion ratios (This system used is described in detail by Guill and Washburn, 1972). These birds were allowed a three-day adjustment period at which time individual feed conversion data were obtained. All birds and feed were weighed at 2-week intervals to determine the growth rate and feed conversion ratio of the five lines and to compare the percent hatch weight of each chick with the feed conversion ratio within lines and between lines at 0-2 weeks on trial, 2-4 weeks on trial and 0-4 weeks on trial. Phenotypic correlations
the randombred population. In Trial 2, the chicks were obtained from the F 3 feed conversion ratio lines of the commercial broiler line. In Trial 3 both the Fi random-bred chicks and the F3 broiler line chicks were used. In each trial all eggs were weighed and divided into groups of 1 g. intervals within each line prior to incubation. In Trial 1 the eggs were incubated in a Jamesway Model 252 forced draft incubator and transferred to hatching trays at 18 days. In Trial 2 the eggs were incubated in a Petersime Model S26I forced draft incubator and transferred to a Petersime Model S26H hatcher at 18 days. A third trial was conducted in which eggs of both the randombred and broiler lines were incubated in the Jamesway Model 252 incubator. At hatching all chicks were weighed, wing banded and the percent weight of chick at hatching to egg weight at setting (percent hatch weight) was determined. The chicks were reared in conventional shavings covered floor pens for the first four weeks for the commercial broiler
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TABLE 2.—Correlations between feed conversion and percent hatch weight at different ages Trial 2 F 3 of Selected Broiler Strain
Trial 1 F! of ARB-ACRB Age
Correlation
Age
Correlation
5-7 wk 7-9 wk 5-9 wk
+ .02 -.06 -.02
4-6 wk 6 8wk 4-8 wk
+ .15 + .02
-.06
RESULTS AND DISCUSSION The mean feed conversion ratios, the mean percent hatch weight and their correlation for each of the five lines of the random breeds (Trial 1) and commercial broilers (Trial 2) are presented in Table 1. Although there was a significant difference in feed conversion ratios between selected lines and between strains the
TABLE 3.—Mean feed conversion ratios (5-9 weeks, Trial 1 and 4-8 weeks, Trial 2) for each percent hatch weight group Trial 2 F3 of Selected Broiler Strain
Trial 1 Fi of ARB-ACRB Feed Conversion Percent Hatch Wt.
Ratio
72(3) 71 (14) 70 (21) 69 (30) 68 (33) 67 (59) 66 (49) 65 (47) 64 (35) 63 (42) 62 (17) 61(11) 60 (12) 56-59 (12) X=66 C.V. 4.0
2.50 2.54 2.54 2.47 2.57 2.52 2.51 2.50 2.51 2.49 2.52 2.56 2.63 2.54 2.52 9.7
( ) number of individuals. C.V. = coefficient of variation.
Deviation From Mean + 2 +2 +2 -5 +5 0 -1 -2 -1 -3 0 +4 + 11
Feed Conversion Percent Hatch Wt.
74-76 (8) 73 (12) 72 (24) 71 (40) 70 (52) 69(46) 68 (58) 67 (52) 66 (30) 65 (28) 64(8) 63(7) 60-62 (9) 68 4.0
Ratio
2.25 2.25 2.25 2.32 2.27 2.22 2.25 2.22 2.24 2.31 2.18 2.27 2.20 2.25 7.5
Deviation From Mean 0 0 0 +7 +2 -3 0 -3 -1 +6 -7 +2 -5
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between percent hatch weight and feed conversion ratios were calculated within strains.
differences between these lines in percent hatch weight were negligible. Furthermore, the correlations between individual feed conversion ratios and percent hatch weight calculated within lines were small and non-significant for both the randombred and the selected broiler lines. Wiley (1950) indicated a greater feed requirement in chicks hatched from small eggs and Kosin et al. (1952) found egg size had a positive effect on body weight gain. However, the results of this study show no relationship between feed conversion or growth rate and percent hatch weight. The LLWV grew at a slightly faster rate, while the HLWV grew at a slightly slower rate than the LLWK, HLWK or C lines, yet their percent hatch weight was not significantly different. The correlations between feed conversion and percent hatch weight for all birds studied are shown in Table 2 with the two age periods separate. There was no indi-
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HATCH WEIGHT AND FEED CONVERSION
Although there was no effect of percent hatch on 4 to 8 week feed conversion, a relationship that existed at an early age may be obscured at four weeks of age. Although it was not possible to measure individual feed conversion from 1 to 28 TABLE 4.—Mean percent hatch weight of all chicks hatched
Fxof ARB-ACRB Trial 1 Trial 2 Trial 3 Hatch 1 Hatch 2
65%
F 3 of Selected Broiler Strain
— 69%
67% 67%
67% 67%
TABLE 5.—Mean feed conversion ratios and percent hatch weight for males and females of the five selected lines of ARB-A CRB from 1 to 5 weeks Percent Hatch Wt. IX WV
LLWK
HLWV
HLWK
Contrc
Feed Conversion Ratio 70 > 66-69 61-65
1.63 1.63 1.70
1.63 1.63 1.73
1.72 1.70 1.67
1.72 1.74 1.65
1.60 1.72 1.64
9 70 > 66-69 61-65
1.61 1.85 1.81
1.61 1.72 1.67
1.76 2.01 1.77
1.76 1.98 1.71
1.75 1.74 1.87
IX = low line, RX = high line; WV = weight variable, WK = weight constant.
days, pen feed conversions were obtained for each line and three hatch weight groups of the randombred lines. These data are presented in Table 5. There were no significant differences in feed conversion between lines or between hatch weight groups although there was a significant difference between sexes. REFERENCES Bray, D. F., and E. L. Iton, 1962. The effect of egg weight on strain differences in embryonic and post-embryonic growth in the domestic fowl. Brit. Poultry Sci. 3: 175-188. Guill, R. A., and K. W. Washburn, 1972. Cages and feed troughs for individual feed consumption experiments. Poultry Sci. 51: 1047-1048. Goodwin, K., 1961. Effect of hatching egg size and chick size upon subsequent growth rate in chickens. Poultry Sci. 40: 1408. Halbersleben, D. L., and F. E. Mussehl, 1922. Relation of egg weight to chick weight at hatching. Poultry Sci. 1: 143-144. Hess, C. W., 1962. Randombred populations of the southern regional poultry breeding project. Wld's. Poultry Sci. J. 19: 147-152. Jull, M. A., and J. P. Quinn, 1925. The relationship between the weight of eggs and the weight of chicks according to sex. J. Agr. Res. 31: 223-226. Jull, M. A., and B. W. Heywang, 1930. Yolk assimilation during the embryonic development of the chick. Poultry Sci. 9: 393-404. Kosin, I. L., H. Abplanalp, J. Gutierrez and J. S. Carver, 1952. The influence of egg size on subsequent early growth of the chick. Poultry Sci. 31: 247-254. O'Neil, J. B., 1950. Relationship of chick size to egg
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cation of a difference in percent hatch weight between the fast growing highly efficient strain and the slower growing randombreds (Table 1). A comparison of the correlations for the two age-periods in which efficiency was measured shows no changes with age. The percent hatch weight for the ARBACRB ranged from 56 to 72 percent with a median of 66% while for the broiler strain the range was 60 to 76% with a median of 68% (Table 3). The mean for the randombred was lower (65%) than that for the selected broiler strain (69%) suggesting that the selected broiler strain which was more efficient in feed utilization after hatching was also more efficient in embryonic development. However, this comparison was made between eggs hatched in different incubators. When eggs from the randombreds and broiler strains were incubated together (Trial 3) the percent hatch weight was 67% for both strains in each of the two hatches (Table 4). This indicates that the comparisons of percent hatch weight obtained by using different incubators and hatchers could result in erroneous conclusions as to the relationship of hatch weight and feed conversion or growth rate.
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size and its effect upon growth and mortality. Poultry Sci. 29: 774. Tindell, D., and D. R. Morris, 1964. The effects of egg weight on subsequent broiler performance. Poultry Sci. 43: 534-539. Upp, C. W., 1928. Egg weight, day old chick weight
and rate of growth in Single Comb Rhode Island Red chicks. Poultry Sci. 7: 151-155. Wiley, W. H., 1950. The influence of egg weight on the pre-hatching and post-hatching growth rate in the fowl. 2. Egg weight-chick weight ratios. Poultry Sci. 29: 595-604.
D. B. BRAGG AND A. I. AKINWANDE Department of Poultry Science, University of British Columbia, Vancouver 8, British Columbia, Canada (Received for publication December 9, 1972) ABSTRACT Six hundred and forty-eight White Leghorn chicks, 408 broiler breeder pullets and 92 Cornish males were utilized in two feeding trials to study the limiting amino acids in wheat protein diets. Results of Trial 1 with White Leghorn chicks indicate that rate of growth was depressed by reducing dietary protein from 20 to 15%. Body weight was not significantly improved by the addition of methionine, leucine, threonine, arginine, valine and isoleucine in various combinations to a wheat-lysine diet. However, treatments that included threonine consistently resulted in slightly heavier birds at four weeks of age than the wheatlysine diet. Results with broiler breeder pullets showed that a 15% protein wheat-lysine diet supported better growth than a wheat-soya diet. Supplemental dietary threonine in the wheat-lysine diet significantly improved growth. Also, diets fortified with threonine and valine improved the growth rate supported by the wheat-lysine diet. Results with Cornish males indicate that wheat protein is limiting in lysine, threonine and valine. A marked response was observed by the addition of both threonine and valine to the wheat-lysine diet. POULTRY SCIENCE 52: 1646-1651, 1973
INTRODUCTION
T
HE value of wheat protein as the sole source of dietary protein in chick diets was first demonstrated by Jeppsen and Graw (1948). Wheat protein was concentrated by removing starch from whole wheat and used to supply protein in a balanced chick diet. These workers concluded from results of the chick study that arginine, leucine, methionine, and tryptophan were adequate to support chick growth. However, lysine supplementation enhanced growth of chicks fed the wheat protein diet. Results of a recent study showed that high protein wheat, used as the only source of dietary protein, failed to support a rate of growth adequate for normal development of White Leghorn chicks
(Bragg et al., 1971). The addition of lysine to the wheat protein diet maintained growth equal to that of a wheat-soya diet containing equal dietary protein. It was also demonstrated that wheat supplied less than 50% of the lysine required for normal growth. Strain and Piloski (1972) compared the nutritional value of various wheat and barley samples by using chicks from three to ten weeks of age. Results indicated that no difference existed among samples of barley or samples of wheat, however, the barley samples support better growth than wheat. These workers suggested that wheat provided more energy than barley. The higher energy would account for the poorer performance in wheat than in barley. Since lysine was the most limiting
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The Nutritional Value of Wheat Protein for Early Growth of Layer and Broiler Breeder Pullets