Egypt. Poult. Sci. Vol (33) (II): (357-369)

(1429)

Egyptian Poultry Science Journal http://www.epsaegypt.com ISSN: 1110-5623 (Print) – 2090-0570 (On line)

STUDY OF SOME PRODUCTIVE PERFORMANCE AND EGG QUALITY TRAITS IN TWO COMMERCIAL LAYER STRAINS G.N. Rayan, M.Y. Mahrous, A. Galal, and A.H. El-Attar Dep. of Poul. Prod., Fac. of Agric., Ain Shams Univ., Cairo, Egypt Received: 20/03/2013

Accepted: 09/05/2013

ABSTRACT: This experiment was conducted to evaluate genetic differences of productive performance and egg quality traits in two commercial layer strains of chickens under prevailing Egyptian environmental conditions. Results demonstrated that brown strain had significantly heavier body weight compared to the white ones. Body weight increased gradually as layers age increased. The strain had insignificant effect on egg number, while layer age had significant effect on this trait. The brown layer hens produced significantly heavier egg weight compared to the white ones. Egg mass of brown eggs were heavier than white eggs. The present results showed that the brown layers significantly consumed more feed compared to the white ones. W-36 layers strain had better feed conversion ratio compared to brown layers strain. Concerning age effect, also feed conversion ratio increases with advancing of layers age, consequently feed efficiency decreases. The brown eggs recorded significantly higher in all eggshell quality traits compared to the white eggs. The mean performance of the eggshell quality traits such as (egg shape index, eggshell breaking strength, shell percentage and shell thickness) declined with advancing layers age with the exception of eggshell weight which increased with layers age. Regarding internal egg quality, it could be noticed that albumen weight and percentage of the brown eggs was significantly higher than that recorded for white ones. While, we found that white eggs had significantly higher Haugh unit compared to the brown ones. Generally, the albumen weight increases with advancing of layers ages. Inversely, albumen as a percentage of total egg weight and Haugh units decreased as layers age increased. The yolk weight, yolk percentage and yolk index increases with advancing of layers ages.

Keywords: Commercial layers, Egg production, Egg quality, Strain, Age. Corresponding author: [email protected]

G.N. Rayan et al

INTRODUCTION Poultry production plays a major role in providing a large and cheap source of animal protein in Egypt. Eggs are the major business outputs in commercial table egg production and the higher egg production the better will be the profit. The layers usually start laying at about 20 weeks of age and peak of egg production is attained during the first production cycle (at about 32 weeks). The average production rate of commercial layers usually remains very close to 0.9 eggs per day (Kekeocha, 1985). However, as the age increases, their egg production decreases. Egg production is a dependent variable and is influenced by several factors like strain, hen age, feeding, mortality, culling, health and management practices. Petek (1999) and Tolimir and Masic (2000) observed variable egg production performance for various strains of chicken. Egg quality is important for consumer, and the economic success of a producer depends on the total number of eggs sold. Egg quality includes several aspects related to the eggshell (external quality) and to the albumen and yolk (internal quality). Egg quality has a genetic basis and the parameters of egg quality vary between strains of hens (Pandey et al., 1986; Silversides et al., 2006). The eggshell quality is an important factor to poultry industry due to reproductive and economic implications, because cracked eggshell presents higher losses for market-egg producers. For consumers is very important the internal egg quality (albumen and yolk) although it cannot be assessed without breaking the egg. With the aging of layers it comes some typical changes of eggs such as: increasing of yolk weight (Suk and Park, 2001) and yolk proportion (Rizzi and Chiericato, 2005) but reducing the percentage of albumen (Van den Brand et al., 2004). Therefore, it is very important to evaluate the egg quality characteristics and

factors affecting them. Singh et al. (2009) found that the H&N White (HN) hens ate less than Lohmann White (LW), Lohmann Brown (LB) and cross hens, but significantly less than all other strains only at 40 wk, feed consumption increased from wk 20 to wk 40 and feed efficiency was greatest at wk 30 and 40. Several investigators have compared the eggs of white and brown egglaying strains (Curtis et al., 1985, 1986; Washburn, 1990; Bonekamp et al., 2010). The differences between white and brown egg layers are not due to a direct relationship with eggshell color but, rather, due to differences in the genetic origins of the hens. Therefore, the objectives of this research were to investigate the genetic differences of productive performance and egg quality in two commercial layer strains of chickens under Egyptian environmental conditions. MATERIALS AND METHODS Genetic Flocks and Husbandry: Two commercial laying breeder strains (Hy-Line W-36 and Hy-Line Brown) were used for production of fertile eggs. Day old chicks were transferred after the hatching from EL-Mansouria Poultry Company hatchery, which situated at ELMansouria area, Giza Governorate to the Poultry Breeding Farm (Kalubia government), Poultry Production Department, Faculty of Agriculture, Ain Shams University. All chicks were brooded and reared under similar environmental, managerial and hygienic conditions. The birds fed a commercial diet containing 18% crude protein and 3200 Kcal ME/kg. The feed and water were provided ad libitum. At thirty weeks of age, total sixty layer chickens (30 Hy-Line Brown and 30 HyLine W-36). Females were placed in individual cages until the end of the experiment.

Commercial layers, Egg production, Egg quality, Strain, Age.

calculated by (albumen weight/egg weight) x100. The Haugh units, proposed by Stadelman et al. (1988) were calculated according to the following formula: H.U = 100 Log (H +7.57-1.7 W 0.37 ) Where: H.U = Haugh unit, H = albumen height (mm), W = egg weight (g). Yolk weight was determined by second decimal scale, while yolk percentage was estimated by (yolk weight / egg weight) x100. Yolk index was calculated according to the following equation: yolk height / yolk diameter x 100 (Well, 1968).

MEASUREMENTS AND OBSERVATIONS Body weight and egg production traits: Individual body weight (in grams) for each strain was recorded at 30, 40 and 50 wks of age. Egg production measurements including egg (number, weight and mass) were individually recorded for Brown and W-36 Hy-Line strains throughout 140 days after attain the sexual maturity (20 weeks). Feed consumption and feed conversion ratio: Feed consumption and feed conversion ratio were calculated for both Brown and W-36 Hy-line strains from 30 to 50 weeks of age. The birds were housed in individual cages. Feed consumption was measured weekly and for the whole experiment. Feed conversion ratio was estimated by (feed consumption/egg mass).

Statistical analysis: Data were subjected to statistical analysis using two-way analysis of variance with strain and layer flock age and their interaction using the General Linear Model (GLM) procedure of SAS (2002) as following model; Yijk= μ + Si+ Aj+ (S A) ij+ eijk Yijk = Trait measured, μ= Overall means, Si = Strain effect (i= 1, 2), Aj= flock Age effect (j = 30, 40, 50 wks), (S A)ij = Interaction between strain and age, eijk = Experimental error. When significant differences among means were found, means were using Duncan's multiple range tests.

Eggshell and internal quality traits: At 30, 40 and 50 wks of age, egg quality measurements were determined using 60 eggs (30 Brown and 30 white) for each age. Fresh eggs were collected separately and weighed to the nearest 0.01 g using an electronic digital balance. Length and width of egg were individually recorded by using a digital caliper. Shape index, then, was calculated by (width/length) x100 according to (Carter, 1968). The breaking strength of eggshell was determined according to Fathi and ElSahar (1996) using eggshell strength apparatus. Shell weight was determined to the nearest 0.01 gram. The shell percentage was calculated according to the following equation: Shell percentage (%) = shell weight/egg weight x 100. Shell thickness (mm) with membranes was measured with a 0.001millimeter accuracy using a digital micrometer. Weight of albumen was recorded; albumen percentage was

RESULTS AND DISCUSSION Data manifested in Table (1) clarifies body weight (g) as affected by strain, layer age and their interactions. Results demonstrated highly significant difference between strains for body weight, whereas the brown strain had significantly heavier body weight compared to the white ones. Similar trend was noticed by Singh et al. (2009). They found that brown egg layers were heavier than white egg layers. Concerning age effect, it could be noticed that body weight increased gradually as layers age increased.

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The present results indicated that no significant difference between strains for egg number. Similar trend was obtained by Badawe (2006). Egg production of white egg and brown egg commercial hens was similar, likely because intensive selection of commercial brown egg layers has brought their production to similar levels as those of white egg strains (Scott and Silversides, 2000). Inversely, egg number was significantly affected by layer age, whereas egg number generally decreases with advancing of layer ages. These results are in agreement with those obtained by Ahn et al, (1997) they indicated that age of the hens had a significant (P≤ 0.05) effect on the whole egg production from 28 to 97 weeks old in Single Comb White Leghorn. Egg weight (g) was highly significantly affected by strain; the brown layer hens produced significantly heavier egg weight compared to the white ones. The brown eggs were heavier than those belongs to white strain. Similar trend was noticed by (Ledvinka et al. 2000; Leyendecker et al. 2001a; Vits et al. 2005). They found that brown egg strains laid heavier eggs than white egg ones. The present results showed that the egg weight increased as the layers age progressed. Similar trend was noticed by Peebles et al. (2000), Silversides and Scott (2001), Oloyo (2003), Van den Brand et al. (2004), Rizzi and Chiericato (2005), Johnston and Gous (2007) they found that the egg weight increased with the hens’ age. Egg mass was significantly affected by strain; whereas egg mass of white eggs represented only 94% of that produced by the brown layers in the tested experimental period. No significant difference in egg mass with advancing of layers age. Feed consumption and feed conversion ratio as affected by strain, layer age and their interactions are presented in Table (1). The brown layers significantly consumed more feed compared to the white counterparts. The obtained result corroborates the previous results North

(1984) that there existed higher feed consumption for large-sized chicken than for mini-type white leghorn. With regard to age effect, our results indicated that feed consumption significantly increases as age increased. Similar trend was noticed by Mehta et al. (1986) and Singh et al. (2009) who reported that as the hens aged, feed intake increased, with a corresponding increase in body weights. Concerning Feed conversion ratio, the present results showed that strain and layers age had highly significant effect on Feed conversion ratio. W-36 layers strain had better feed conversion ratio (1.98) compared to brown layers strain (1.80). Feed conversion ratio increases with advancing of layers age. Consequently, feed efficiency decreases. Similar result was obtained by Yasmeen et al. (2008). Egg quality traits: Eggshell quality: Eggshell quality as affected by strain, layer age and their interactions is presented in Table (2). It could be noticed that the brown layer hens produced eggs with significantly higher shape index compared to the white ones. The values obtained in our study for egg shape index were also similar to the finding of Monira et al., (2003) and Brand et al., (2004). The present results revealed that there was a significant decrease in egg shape index with advanced of layers age. Similar trend was reported by Choprakarn et al. (1998), Gunlu et al. (2003) and Brand, et al. (2004). They pointed that shape index of the eggs decreased with age because shape index is directly proportional to egg width and it is inversely related to egg length, which implies that with increasing age, the rate at which eggs becomes longer is faster than rate of being wider. Eggshell weight (g) was significantly affected by strain. The brown hens had significantly heavier shell weight compared to the white ones. Exactly this is

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observed by Scott and Silversides (2000), Renema et al. (2001). They indicated that eggshell weight for brown eggs were heavier compare to white eggs strain. shell weight increased as age increased. Similar trend was noticed by Suk and Park (2001) also they observed that the eggshell was heavier in older hens. A number of studies have shown that eggshell weight increased as the hen's age increased (Nys, 1986; Roberts, 2004 and Singh et al. 2009). Therefore, the reason for heavier eggshells of older layers might be their production of heavier eggs than those of young. Shell percentage can be use to estimate the eggshell quality (Mertens et al. 2006). The present results showed that the brown eggs had significantly higher shell percentage compared to the white ones. Similar trend was reported by Curtis et al. (1986) and Scott and Silversides, (2000). Likewise, Silversides and Scott (2001) noticed that the shell, as a percentage of egg weight, decreased more for ISA-White eggs with increasing age of the hen than it did for ISA-Brown eggs. With respect to age effect, we found that shell percentage decreases gradually with advancing of hen's ages. The mean values were 9.22, 8.87 and 8.56 respectively. Significant difference between strains for shell thickness with membranes was detected; the brown eggs recorded significantly higher shell thickness with membranes compared to the white counterparts. The mean values were 0.365 and 0.346 (mm) for Brown and W-36, respectively. This result was in conformity with the findings of Ledvinka et al. (2000) and Badawe (2006) they concluded that brown eggs had a thicker eggshell than the white ones. It could be observed shell thickness with membranes decreases with advancing of hens' ages. In agreement with these finding, Bare and Striem (1998); Suk and Park (2001) pointed that eggshell thickness decreased with advancing of hens age. A probable explanation for thin eggshell in older hens may be lessening of

calcium deposition with the passage of time (Bare and Striem, 1998). Results indicated to presence significant difference between strains for shell strength. The brown eggs recorded significantly higher eggshell breaking strength (4.00 kg/cm2) compared to the white eggs (3.64 kg/cm2). The previous result also confirmed the findings of Fathi and El-Sahar (1996) they stated that mean of breaking strength of the brown shells was approximately 13% higher than those of white ones. Eggshell breaking strength decreases with advancing of hen's ages. Similar result was obtained by Bare and Striem (1998) and Edmond et al. (2005). Several reasons have been advanced to explain this change in shell strength with age. It has been proposed that the amount of hen Ca absorbs and retains also, the skeletal Ca available for shell calcification decrease with age. The results of the present study was confirmed such theory. Likewise, Ousterhout (1981) observed that egg weight increased at a faster rate than shell weight resulting in a decrease in the amount of shell that covers the egg. In addition, when stressed with inadequate Ca, old hens were able to maintain shell strength as well as young hens, the increasing egg size with progressing age without a concomitant increase in shell weight as an important contributing factor to the decreasing shell strength with age. Internal egg quality: Data presented in Table (3) showed internal egg quality traits (Albumen and Yolk) as affected by strain, layer age and their interactions. The albumen weights of the brown eggs were significantly heavier than that of white ones. Likewise, as indicator to egg weight it was highly significantly affected by layers ages, whereas the albumen weight increases with advancing of layers ages. Similar result was obtained by Rossi and Pompei (1995) and Suk and Park (2001) observed that the albumen weight increased with advancing

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age of layers. Albumen percentage of the brown eggs was 67.98% and this value was higher than that of white eggs (65.71%). Also, the albumen percentages were significantly affected by layers ages, this result in accordance with (Van den Brand et al. 2004; Rizzi and Chiericato 2005) they observed that the albumen as a percentage of total egg weight decreased with advancing age of the hens. Albumen height and Haugh units (HU) are traits used to evaluate albumen quality, which deteriorates with age (Liljedahl et al., 1984). The Haugh unit has been used extensively (Williams, 1992). In this study, we found that white eggs had significantly higher Haugh unit compared to the brown ones. Similar trend was noticed by Leyendecker et al. (2001b). With reference to age effect, a significant depressing effect was obtained for the values of Haugh units, whereas Haugh units decreased as layers age progressed. In agreement with these findings, Verheyen and Decuypere (1991); Yasmeen et al. (2008) also found that Haugh unit values decreased with advancing the layers age. Yolk weights of the white eggs were significantly heavier than those of brown ones. Leyendecker et al. (2001b)

detected a significantly higher yolk weight for white egg (Lohmann LSL) in comparison with the brown Lohmann Tradition. From physiological stand point of view, the egg weight is positively correlated with progressing age of hen. Such phenomena held true, also either for yolk or albumen weight as a major egg components. The yolk weight increases with advancing of layers ages. Similar trend was observed by Suk and Park (2001); Yasmeen et al. (2008) and Singh et al. (2009). A probable explanation for increased yolk weight in older layers might be reflected to heavier eggs produced by them. Regarding yolk percentage, in general, yolk percentage of the white eggs was significantly heavier than that of brown eggs. The relative yolk weight increases with advancing of layers age. The obtained result corroborates the previous results Rossi and Pompei (1995); Rizzi and Chiericato (2005) that there existed that yolk percentage increased with the hens’ age. The brown eggs recorded significantly higher yolk index compared to the white ones. Results showed that yolk index significantly increases as layer was progressed age.

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Table (1): Body weight, egg production traits, feed consumption and feed conversion ratio as affected by strain, layer age and their interactions (Means ± SE). Age (A), Strain (S) wk Brown W-36 Body weight (g) 30 1695.33 ±21.93 1357.80 ±19.66 40 1802.83 ±23.17 1471.67 ±18.80 50 1898.10 ±20.98 1534.00 ±21.01 Overall 1798.76a 1454.49b Egg number 30-35 30.80 ±0.45 29.23 ±0.54 35-40 30.00 ±0.48 30.27 ±0.36 40-45 28.50 ±0.50 28.37 ±0.53 45-50 29.47 ±0.46 29.00 ±0.50 Overall 29.69 29.22 Egg weight (g) 30-35 63.04 ±0.32 59.79 ±0.50 35-40 63.01 ±0.41 60.16 ±0.29 40-45 65.07 ±0.54 62.72 ±0.57 45-50 66.30 ±0.72 63.17 ±0.26 a Overall 64.35 61.46b Egg mass (g) 30-35 1941.01 ±29.37 1748.60 ±36.71 35-40 1889.18 ±30.22 1820.85 ±23.55 40-45 1852.79 ±32.51 1777.61 ±34.67 45-50 1953.33 ±36.08 1832.09 ±33.47 Overall 1909.08a 1794.79b Feed consumption (g) 30-35 3621.87 ±9.79 3066.10 ±20.53 35-40 3635.73 ±26.10 3144.47 ±36.88 40-45 3747.93 ±27.56 3254.53 ±23.52 45-50 3952.37 ±27.11 3358.07 ±71.39 Overall 3739.48a 3205.79b Feed conversion ratio 30-35 1.88 ±0.03 1.78 ±0.04 35-40 1.94 ±0.04 1.74 ±0.03 40-45 2.04 ±0.03 1.85 ±0.04 45-50 2.05 ±0.05 1.85 ±0.05 a Overall 1.98 1.80b

363

Overall

Prob. A

S*A

0.0001

0.0001

NS

NS

0.001

NS

0.0001

0.0001

NS

0.0001

NS

NS

0.0001

0.0001

NS

0.0001

0.001

NS

S

1526.57c 1637.25b 1716.05a 30.02a 30.13a 28.43b 29.23ab 61.41b 61.59b 63.89a 64.73a

1844.81 1855.02 1815.20 1892.71 3343.98c 3390.10c 3501.23b 3655.22a 1.83b 1.84b 1.95a 1.95a

G.N. Rayan et al

Table (2): Eggshell quality as affected by strain, layer age and their interactions (Means ± SE). Layers age Strain (S) (A), wk Brown W-36 Egg shape index (%) 30 78.00 ±0.43 75.57 ±0.29 40 75.97 ±0.45 74.14 ±0.48 50 74.00 ±0.66 73.28 ±0.68 a Overall 75.99 74.34b Eggshell weight (g) 30 5.38 ±0.07 4.93 ±0.11 40 5.77 ±0.14 5.38 ±0.11 50 5.98 ±0.12 5.71 ±0.12 Overall 5.71a 5.34b Shell percentage (%) 30 9.42 ±0.19 9.01 ±0.22 40 9.08 ±0.23 8.66 ±0.18 50 8.67 ±0.16 8.45 ±0.20 a Overall 9.06 8.71b Shell thickness with membranes (mm) 30 0.391±0.018 0.371±0.008 40 0.364±0.011 0.354±0.007 50 0.341±0.006 0.312±0.007 Overall 0.365a 0.346b Eggshell breaking strength (kg/cm2) 30 4.47 ±0.22 4.04 ±0.16 40 3.98 ±0.19 3.70 ±0.21 50 3.57 ±0.27 3.15 ±0.21 a Overall 4.00 3.64b

364

Overall

Prob. A

S*A

0.0001

0.0001

NS

0.0001

0.0001

NS

0.03

0.005

NS

0.02

0.0001

NS

0.03

0.0002

NS

S

76.79a 75.05b 73.65c 5.16c 5.58b 5.85a 9.22a 8.87ab 8.56b 0.381a 0.359b 0.327c 4.25a 3.84a 3.37b

Commercial layers, Egg production, Egg quality, Strain, Age.

Table (3): Internal egg quality as affected by strain, layer age and their interactions (Means ± SE). Layers age Strain (S) (A), wk Brown W-36 Albumen weight, g 30 43.61 ±0.94 39.75 ±0.86 40 43.22 ±0.67 39.50 ±0.94 50 44.53 ±0.70 41.74 ±0.88 Overall 43.78a 40.30b Albumen, % 30 69.68 ±1.32 67.47 ±1.34 40 67.48 ±0.52 65.15 ±0.58 50 66.81 ±0.44 64.49 ±0.69 Overall 67.98a 65.71b Haugh unit, (HU) 30 87.43 ±1.54 95.10 ±1.17 40 85.27 ±1.67 93.81 ±0.94 50 82.45 ±1.89 90.38 ±1.54 Overall 84.93b 93.19a Yolk weight, g 30 11.57 ±0.11 11.54 ±0.09 40 14.84 ±0.28 15.49 ±0.23 50 16.27 ±0.22 16.95 ±0.23 Overall 14.23b 14.64a Yolk, % 30 18.61 ±0.29 19.63 ±0.26 40 23.11 ±0.47 25.74 ±0.45 50 24.16 ±0.35 25.87 ±0.42 Overall 21.97b 23.75a Yolk index 30 42.64 ±0.74 40.62 ±0.58 40 43.97 ±0.74 42.26 ±0.56 50 45.05 ±0.55 41.12 ±0.66 Overall 43.89a 41.35b NS= Non significant.

365

Overall

Prob. A

S*A

0.0001

0.08

NS

0.002

0.003

NS

0.0001

0.007

NS

0.01

0.0001

NS

0.0001

0.0001

NS

0.0001

0.03

NS

S

41.75ab 41.42b 43.21a 68.61a 66.35b 65.71b 91.43a 89.77a 86.17b 11.55c 15.15b 16.59a 19.10b 24.38a 24.97a

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local breeds. Ital. J. Anim. Sci. 4: 160-162. Roberts, J. R. (2004). Factors affecting egg internal quality and egg shell quality in laying hens. J. Poult. Sci., 41: 161-177. Rossi, M., and Pompei, C. (1995). Changes in some egg components and analytical values due to hen age. Poult. Sci., 74: 152-160 SAS institute (2002). SAS/STAT User's Guide statistics Ver. 9.1; SAS institute Inc., Cary, NC. Scott , T. A. , and F. G. Silversides (2000) . Effect of storage and strain of hen on egg quality. Poult. Sci. 79 : 1725 – 1729 . Silversides , F. G. , D. R. Korver , and K. L. Budgell (2006) . Effect of strain of layer and age at photostimulation on egg production, egg quality, and bone strength. Poult. Sci. 85 : 1136 – 1144 . Silversides, F. G., and T. A. Scott (2001). Effect of storage and layer age on quality of eggs from two lines of hens. Poult. Sci. 80:1240–1245. Singh, R., K. M. Cheng, and F. G. Silversides (2009). Production performance and egg quality of four strains of laying hens kept in conventional cages and floor pens. Poult. Sci. 88:256-264. Stadelman, W.J., V.M. Olson, G.A. Shemwell and S. Pasch (1988). Egg and Poultry Meat Processing. Ellis-Horwood Ltd, Chichester, UK. Suk, Y.O., C. Park (2001). Effect of breed and age of hens on the yolk to albumen ratio in two different genetic stocks. Poult. Sci. 80: 855858. Tolimir, N. and Masic, B. (2000). The results of European egg production

tests in 19971998. Zivinarstvo. 35(5): 66-68. Van den Brand H., H.K. Parmentier and B. Kemp (2004). Effect of housing system (outdoor vs. cages) and age of laying hens on egg characteristics. Br. Poult. Sci. 45: 745-752. Verheyen, G. and E. Decuypere (1991). Egg quality parameters in second and third laying years as a function of the moulting age, strain and moulting methods. Archiv fur Geflugelkunde, 55: 275-282 (Poult. Abst., 18(5): 1068, 1992). Vits, A., Weitzenburger, D., Hamann, H., Distl, O. (2005). Production, egg quality, bone strength, claw length, and keel bone deformites of laying hens housed in furnished cages with different group sizes. Poult Sci 84: 1511-1519. Washburn, K. W. (1990). Genetic variation in egg composition. Pages 781–798 in: Poultry Breeding and Genetics. R. D. Crawford, ed. Elsevier Scientific Publishers, New York, NY. Well, R. J. (1968). The measurement of certain egg quality: A study of the hens. Ed. by T. C. Carter Pub. Oliver and Boyd Edinburgh P. 220226 and 235-236. Williams, K. C. (1992). Some factors affecting albumen quality with particular reference to Haugh unit score. World’s Poult. Sci. J. 48: 5– 16. Yasmeen, F., S. Mahmood, M. Hassan, N. Akhtar and M. Yaseen (2008). Comparative productive performance and egg characteristics of pullets and spent layers. Pakistan Vet. J., 28(1): 5-8.

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‫‪Commercial layers, Egg production, Egg quality, Strain, Age.‬‬

‫الملخص العربي‬ ‫دراست على األداء اإلوتاجى وصفاث جودة البيض فى ساللتيه مه الذجاج البياض التجاريت جمال‬ ‫واصر ريان‪ ،‬محمود محروس‪ ،‬أحمذ جالل‪ ،‬أحمذ حاتم إبراهيم العطار‬

‫قسن إًخبج الذّاخي‪ ،‬مليت الضساػت ‪ -‬خبهؼت ػيي شوس‪ ،‬القبُشة – هصش‬ ‫أخشيج ُزٍ الخدشبت لخقذيش االخخالفبث الْساثيت لألداء اإلًخبخٔ ّصفبث خْدة البيط فٔ ساللخيي هي الذخبج‬ ‫البيبض الخدبسيت ححج الظشّف البيئيت الوصشيت‪ .‬حن حشبيت ػذد ‪ 06‬دخبخت بيبظت (‪ 06‬دخبخت ُبٓ اليي بٌٔ‪06 ،‬‬ ‫دخبخت ُبٓ اليي أبيط) فٔ أقفبص فشديت‪ّ .‬أثٌبء الفخشة هي ‪ 06‬الٔ ‪ 06‬أسبْع هي الؼوش حن أخز بؼط الوقبييس‪ :‬هثل‬ ‫ّصى الدسن‪ ،‬هقبييس إًخبج البيط‪ ،‬االسخِالك الغزائٔ ّهؼبهل الخحْيل الغزائٔ ّرلل بصْسة فشديت لنل ساللت‪.‬‬ ‫ببإلظبفت الٔ رلل حن حقذيش صفبث خْدة البيط الذاخليت ّصفبث خْدة القششة ببسخخذام ػذد ‪ 06‬بيعت (‪ 06‬بٌٔ‪06 ،‬‬ ‫أبيط) لنل ػوش‪ .‬أظِشث الٌخب ئح أيعب لْحظ أى الساللت البٌيت سدلج أّصاى خسن أثقل هؼٌْيب هقبسًت ببلساللت البيعبء‪،‬‬ ‫ّيضداد ّصى الدسن حذسيديب بضيبدة الؼوش‪ .‬لن يني للساللت حأثيش هؼٌْٓ ػلٔ ػذد البيط‪ ،‬فٔ حيي أى ػوش الذخبخبث مبى‬ ‫لَ حأثيش هؼٌْٓ ػلٔ ُزٍ الصفت‪ .‬أًخدج الذخبخبث البٌيت ّصى بيط أثقل هؼٌْيب ببلوقبسًت بوثيلخِب البيعبء‪ .‬مخلت البيط‬ ‫ببلٌسبت للبيط رّ القششة البٌيت مبًج أثقل ببلوقبسًت ببلبيط رّ القششة البيعبء‪ .‬أظِشث الٌخبئح الحبليت أى االسخِالك‬ ‫الغزائٔ للذخبخبث البٌيت أػلٔ هي هثيلخِب البيعبء‪ .‬الساللت البيعبء مبًج أفعل ببلٌسبت لوؼبهل الخحْيل الغزائٔ هي‬ ‫الساللت البٌيت‪ّ ،‬ببلٌسبت لخأثيش الؼوش ّخذ أى هؼبهل الخحْيل الغزائٔ يضداد بضيبدة الؼوش ّببلخبلٔ حقل مفبءة الخحْيل‬ ‫الغزائٔ‪ .‬لْحظ فٔ ُزٍ الذساست أى البيط البٌٔ سدل اسحفبػب هؼٌْيب فٔ مل صفبث خْدة القششة ّرلل ببلوقبسًت ببلبيط‬ ‫األبيط‪ّ .‬هخْسط األداء ل صفبث خْدة قششة البيط هثل (دليل شنل البيط‪ ،‬قْة مسش القششة‪ً ،‬سبت القششة‪ ،‬سول‬ ‫القششة) يقل هغ حقذم ػوش الذخبخبث البيبظت فيوب ػذا ّصى القششة ّالزٓ يضداد هغ حقذم الؼوش‪ .‬فيوب يخؼلق بدْدة البيط‬ ‫الذاخليت لْحظ أى ّصى ًّسبت البيبض للبيط البٌٔ مبى أػلٔ هؼٌْيب هي البيط األبيط‪ ،‬فٔ حيي أى البيط األبيط‬ ‫مبى أػلٔ هؼٌْيب ببلٌسبت لْحذاث ُْ‪ .‬ػوْهب‪ ،‬يضداد ّصى البيبض هغ حقذم ػوش الذخبخبث ّػلٔ الؼنس ّخذ أى الٌسبت‬ ‫الوئْيت للبيبض ّّحذاث ُْ حقل هغ صيبدة ػوش الذخبخبث‪ .‬يضداد مل هي ّصى الصفبس‪ ،‬الٌسبت الوئْيت للصفبس‪ ،‬دليل‬ ‫الصفبس هغ حقذم ػوش الذخبخبث‪.‬‬

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