USING SCANNING ELECTRON MICROSCOPY TO DETECT THE GENETIC DIVERSITY OF EGGSHELL QUALITY AMONG SOME...

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International Poultry Conference 10-13 March 2009. Taba – Egypt

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USING SCANNING ELECTRON MICROSCOPY TO DETECT THE GENETIC DIVERSITY OF EGGSHELL QUALITY AMONG

SOME EGYPTIAN DEVELOPED BREEDS OF CHICKEN

Fathi1, M. M., S. A. El-Safty1 and Y. K. Afifi2

1 Dept. of Poultry Production, Fac. of Agric., Ain Shams Univ., Cairo, Egypt 2 Anim. Prod. Res. Inst., Agric. Res. Center, Ministry of Agric., El-Sabahia, Alex,

Egypt

ABSTRACT: Genetic differences in ultrastructural of eggshell between some developed local strains (Bandara, Gimmizah, Mandara and Matrouh) throughout the mid egg production period (at 42 and 48 weeks of age) were evaluated by using scanning electron microscopy (SEM). Also, egg production traits, internal and external egg quality measurements were determined. The main results can be summarized as follows:

- Gimmizah layers had significantly heavier body weight measured at sexual maturity as compared to the other strains. On the other hand, Mandara females reached sexual maturity earlier than the others.

- With respect to internal egg quality measured at 42 weeks of age, Gimmizah, Bandara and Matrouh females produced heavier egg weight compared to Mandara one and the differences were highly significant.

- At 42 weeks of age, it is of interest to note that Mandara, Gimmizah and Matrouh strains, respectively had significantly higher wet eggshell % compared to Bandara counterpart. While, Mandara and Matrouh strains had a thicker eggshell compared to Gimmizah strain, but Bandara strain was intermediate.

- Concerning data obtained at 48 weeks of age, Bandara strain was recorded the highest figure of shape index, whilst, both Gimmizah and Matrouh had the lowest values of such trait, but Mandara stain was intermediate estimate. The higher figures of yolk index were recorded by both Gimmizah and Bandara strains, whereas the lower values were recorded by both Matrouh and Mandara, respectively.

- According to the results obtained by SEM technique, ultrastructural analysis revealed a significant effect of strains for total structural score. The eggshell of Bandara strain had many ultrastructural faults, where Type Bs and cubic calcite have been deposited in the intermammillary space.

- Type A bodies increased in eggs of Matrouh strain, also the lack of establishment between shell and membrane fibers was observed. Contrarily, the eggshell of Mandara strain had the lowest total structural score, meaning good ultrastructure of mammillary layer compared to the other strains.

In conclusion, the genetic diversity of eggshell quality among the strains using SEM was more obvious, especially in Mandara strain, where this strain had a good caps and confluence as compared to others. So, the ultrastructural measurements of the eggshell must be taken in our concept through poultry breeding programs and crossbreeding systems. Key words: Ultrastructural measurements; scanning electron microscopy; eggshell quality; local strains; egg production traits.

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INTRODUCTION Unquestionably, several factors can affect the poultry egg characteristics,

including hen age, environment, nutrition and genetics. Genetic differences in eggshell formation characteristics exist between breeds, strains and families within the species (Fathi, 2001; Monira et al., 2003; Anderson et al., 2004; El-Safty, 2004; Bain, 2005; Hunton, 2005; Bain et al., 2006a).Cracked eggs are therefore, of major economic significance to those involved in the production and marketing of eggs, but equally if cracked eggs pass through the system undetected, they can also constitute a risk to food safety. Eggshell quality has always been a problem in the layer industry from an economic standpoint of view. Cracked and damaged eggs can account for between 6 and 8% of total production (Hamilton et al., 1979) and can be particularly problematic in older flocks. This results in substantial economic loss to the egg industry (Hunton, 1995). The economic losses on a worldwide basis are difficult to estimate but for the UK industry an estimate can be made using the statistical data published annually. In 2005, for example, the total eggs passing through UK packing stations was estimated to be 24 741 000 cases (360 eggs per case). Assuming an average breakage of 5%, then the losses sustained by the UK industry in 2005 could have amounted to as much as £16.7 million, based on an average packer to producer price of 45 pence/dozen (Bain et al., 2006b).

Any approach which aims at improving the quality and safety of eggs, is of limited value unless it can relate to the incidence of breakages in the field and can be applied either directly to breeding programs or used as online tools for quality assurance. Online systems require the method of assessment to be non-destructive. This is probably not so important for breeding companies, who tend to gauge the usefulness of an eggshell quality measurement by its ease of measurement, its heritability and its genetic correlation with other phenotypic traits (Bain, 2005).

Eggshell breakage depends on both the strength of eggshell and the magnitude of mechanical load applied during the moment of lay, collection, sorting and transportation. Shell strength is related not only to the geometrical property but also to the mechanical and material properties. Recently, a new method for the measurements of the mechanical and material properties of eggshells has been established that has provided new insights on shell quality (Coucke et al., 1999; De Ketelaere et al., 2002).

When the scanning electron microscope became widely available to the scientific community, it was natural that it would be used to investigate the structure of the eggshell in greater detail than was previously possible (Hunton, 2005). During the last two decades, extensive researches were done at the University of Glasgow, UK on microstructure of eggshell to identify a variety of abnormalities which resulted in weakening of the structure and a risk of crack formation. In this concern, the current study was performed to detect the genetic diversity of eggshell quality among some Egyptian local strains (Bandara, Gimmizah, Mandara and Matrouh) using scanning electron microscopy data. MATERIALS AND METHODS Experimental design The present study was conducted at El-Sabahia Station, Alex, Animal Production Research Institute, Agriculture Research Center, Ministry of Agriculture. During the mid egg production period (from age at sexual maturity up to 48 weeks of age), a total of 160 laying hens representing four local strains (Bandara, Gimmizah, Mandara and Matrouh) were used in this trial (40 each). Laying hens were housed in an individual wire cages in an open sided house with experimental units of 5 hens sharing access to a common feed trough. The lighting schedule was maintained at 17 hours of daylight and 7 hours of darkness throughout the study. Diet was

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formulated to contain approximately 17.5 % crude protein and 2875 ME kcal/kg in a typical layer diet (NRC, 1994) and was mixed every three weeks. Measurements and Observations At maturation age, both body weight and age were determined for all local strains except Matrouh strain (not available). Egg number was recorded for the first 90 days of laying period. Also, eggs were individually weighed for each hen throughout the considered period. Egg mass was also calculated. At 42 and 48 weeks of age, three hundred and twenty eggs were collected from all breeds (80 each) to measure internal and external egg quality traits. The dimensions of eggs (width and length) were measured using digital caliper to calculate shape index. Each egg was first weighed to the nearest 0.1g and broken open. The height of albumen and yolk was measured using a micrometer mounted on a stand with a platform on which the liquid content was placed. Each egg yolk was separated from the albumen using a plastic egg separator, rolled on a damp paper towel to remove any adhering albumen and weighed. Albumen yield was determined by subtraction of the yolk and shell with shell membranes intact from the whole egg weight. The percentage of egg components (yolk, albumen and shell) was calculated as the ratio of egg component to egg weight multiplied by 100. Yolk index (yolk height/yolk diameter) was also calculated. Haugh units were calculated according to Stadelman et al. (1988). Wet eggshell was weighed before drying to the nearest 0.01g and then reweighed after drying. The percentage of both wet and dry eggshell was calculated. The thickness (mm) of the shell was measured at three deferent points in the middle part of the egg using a dial gauge micrometer. The shell breaking strength (kg/cm2) was determined according to Fathi and El-Sahar (1996) using their eggshell strength apparatus. The eggshell surface area (S) was calculated using the following equation: S =K EW0.67

Where; EW= egg weight K= 4.63 (Etches, 1996) Shell weight per unit surface area (mg/cm2) was also calculated. Egg specific gravity was determined by the floating method, which involved placing the eggs in a series of saline solutions with increment of 0.005 units. Preparation of samples for ultrastructural analysis using SEM

Specimens for ultrastructural analysis were prepared by cutting a piece (1 cm2) of shell from the equatorial region of each egg. The shell membranes were carefully removed by first soaking in water. The loosely adhering membranes were then gently peeled from the edge of the sample inwards. To remove the remaining tightly bound membrane fibers, each sample was then immersed overnight in 6 % sodium hypochlorite. Thereafter, the specimen was rinsed with water and left to dry at room temperature. Following these preparative treatments, two samples from each egg were mounted in innerside uppermost on aluminum stubs, coated with gold for 3 min in an Emscope Sputter Coater. These samples were examined using JEOL JSM-T330A scanning electron microscopy at 15 Kv. The incidence of ultrastructural variants at the level of the mammillary layer was assessed according to the methodology and terminology developed by the Poultry Research Unit, University of Glasgow (Bain, 1990, 1992) and later modified by Darnell-middleton (1999). Ultrastructural integrity of each egg was summarized by means of a total ultrastructural score as outlined by Fathi (2001). Statistical analysis Data were subjected to a one-way ANOVA using JMP (SAS Institute, 2000) with strain as fixed effect. All data are presented as means and the pooled SEM. Significant differences among means were separated by the Tukey’s test. RESULTS AND DISCUSSION

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Table (1) shows body weight, age at sexual maturity and egg production traits of the considered local breeds. It could be observed that the body weight of Gimmizah birds recorded at maturation age was significantly heavier as compared to the others. However, the existing of Plymouth Rock strain as a dam of Gimmizah breed may be responsible for heavier body weight (high heritable trait). Sexual maturity was delayed by over a month for Bandara hens compared to Mandara ones. While, Gimmizah hens reached sexual maturity less than 10 days after Mandara breed. At sexual maturity, Gimmizah hens weighed more and laid larger eggs compared to the others breeds. The previous result may be attributed for being Mandara breed derived from Dokki4 dams (local breed), while Bandara breed derived from Cornish dams (exotic breed). This favorable effect associated with maternal line on maturation age of their progeny may be due to the additive cytoplasmic inheritance which gives only from dams (El-Safty et al., 2003). As expected, both Gimmizah and Bandara females produced heavier egg weight compared to Mandara counterpart as a result of its heavier body weight. Regarding egg number and egg mass traits, there was no significant difference among all breeds. The effect of breed on egg quality (internal and external) was examined during the mid egg production cycle (at 42 and 48 weeks of age). The internal egg quality traits at 42 weeks of age are presented in Table (2). Gimmizah, Matrouh and Bandara females had a significantly heavier egg weight as compared to Mandara strain. With respect to shape index, shell % and Haugh units, there was no significant difference among all genetic groups. Furthermore, the highest significant figures of yolk index was recorded by Bandara strain, whilst both Mandara and Matrouh had the lowest values, Gimmizah layers was intermediate. Regarding albumen %, both Bandara and Gimmizah were significantly superior as compared to both Mandara and Matrouh females. All of Matrouh, Mandara and Gimmizah, respectively had the highest values of yolk percentage compared to Bandara counterpart. Empirical data of eggshell quality among the studied strains at 42 weeks of age are shown in Table (3). Both Mandara and Matrouh Bandara eggs had more moisture content of the eggshell (wet shell %) as compared to the others. Likewise, Mandara, Bandara and Matrouh had significantly higher dry shell % comparably with Gimmizah. From the previous result, it could be noticed that Mandara, Matrouh and Bandara eggs had a spongy constitute in its eggshells. There was a significant difference among strains for shell thickness trait. However, Matrouh strain had a thicker eggshell, while Gimmizah was the thinner eggshell, both Bandara and Mandara were intermediate. Mandara strain had a stronger eggshell followed by Matrouh and Gimmizah strains, but Bandara eggshell recorded the lowest value. This finding is fully in agreement with the results of Fathi (2001) and El-Safty (2004), who found that existing Leghorn breed in the genetic background of Mandara, may be responsible for higher resistance to breaking force. Also, Hocking et al. (2001) and Anderson et al. (2004) reported that there is strong evidence that genetic variation exists for eggshell strength. Concerning shell area and shell weight per unit of area measurements, no statistically significant difference was observed among strains. However, the changes in egg quality over the production cycle agree with previous reports (Silversides and Scott, 2001; Silversides et al., 2006). Concerning egg specific gravity measurement, the result revealed that Matrouh strain had significantly higher figures compared to Gimmizah one and the others were intermediate. Furthermore, the differences in specific gravity of fresh eggs are due to almost entirely to differences in amount of shell percent and it appears that egg specific gravity was the best measurement of shell strength (Anderson et al., 2004). At 48 weeks of age, both internal and external egg quality traits were re-evaluated for all strains Table (4, 5). The same trend was observed for egg weight

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trait, where Gimmizah strain recorded the heaviest egg weight, while the others were in harmony in such trait (Table 4). Bandara strain recorded the highest value of shape index, but Gimmizah and Matrouh eggs recorded the lowest figure. That is meant the eggs produced from Gimmizah and Matrouh strains were more spherical in shape compared to all other groups. In term of yolk index, both Bandara and Gimmizah strains had significantly higher figure than those of the remaining strains. Regarding egg components (albumen, yolk and shell percentages) and Haugh units, no significant difference was observed among the experimental strains. The previous results may be due to the fact that Mandara strain was derived from the Leghorn strain, which represents the main pure line in all commercial layers (egg-type hens). Eggshell quality measurements among the studied developed local strains at 48 weeks of age are summarized in Table (5). All of Mandara, Matrouh and Gimmizah strains recorded the highest values of wet shell % comparably with Bandara one. Moreover, the difference among them was highly significant. For all of dry shell %, breaking strength, eggshell area and specific gravity measurements among strains, the differences were not significant. Eggs from both Mandara and Matrouh strains accompanied by significantly higher shell thickness as compared to Gimmizah one, Bandara eggshell thickness was intermediate measure. Shell weight per unite of eggshell area was significantly higher in both Bandara and Mandara strains when compared with both Gimmizah and Matrouh counterparts.

Ultrastructural examination of eggshells has greatly enhanced our understanding of the eggshell architecture and has reinforced the view that the mechanical properties of eggshells cannot be defined by a simple thickness measurement (Bain, 2005). Solomon, (1991) described twelve structural variations in the mammillary layer of weak and poor quality eggshells. According to SEM observations of the current study (Table 6), ultrastructural analyses revealed a significant effect of breeds for total score. As shown in Fig (1) the eggshell of Bandarah breed had many ultrastructural faults. Mammillae alignment and late fusion resulting in a long continuous groove between the cones were observed. Likewise, type Bs and cubic calcite have been deposited in the intermammillary space.

Some variations in cap diameters were apparent in Gimmiza breed when compared with the other breeds. A good shell quality shell should have mammillary bodies that are even in size and distribution, and rounded so that there can be maximum attachment to the fibers of the outer membrane. In some cases of Gimmiza breed cavities could be seen in mammillary and fissures within or between mammillae were also observed. Poor quality caps, which allow no firm attachment with the membranes were observed in Matrouh images. Type A bodies, which have no mammillary cap, increased in eggs of Matrouh breed (Fig. 2). Alignment of the mammillae in Bandara breed was found to be correlated with eggshell strength. This may reflect the fact that if an egg is subjected to mechanical trauma, then the crack line will tend to follow the path of least resistance and ordered mammillae provide such a pathway (Bain, 1990; Nascimento et al., 1992; Fathi, 2001).

The lack of establishment between shell and membrane fibers at this point obviously creates the ideal portal crack and bacterial penetration. There was considerable variation in shape and spacing of mammillary bodies. Some were conical rather than rounded with little contact with membrane fibers, thereby resembling the type A mammillary bodies as described by Bain (1990) and Solomon (1991).

The eggshells of Mandara had good confluence (Fig. 3), while Gimmiza breed had good organized caps (Fig. 4) and in turn, the highest total structural score compared to the other breeds. The last observation is fully in agreement with the findings of Fathi (2001). However, the total structural score proved to be a reliable

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instrument to measure the ability of a shell to stand strongly against the load. Because no one feature could be isolated as the causative factor of lower resistance, and because in every single shell a number of structural modifications will be present, only their overall magnitude, represented by the total structural score, could ultimately determine the probable performance of the shell as a barrier to bacterial penetration (Nascimento et al., 1992). Several studies on ultrastructural prospective are ongoing and some of them are being conducted in collaboration with major primary breeders. We hope that this cooperation extended to the type of proteins forming the shell matrix to be embedded in selection programs within the foundation lines used for breeding egg layers. REFERENCES Anderson, K.E.; Tharring, J.B.; Curtis, P.A. and Jones, F.T. (2004). Shell

characteristics of eggs from historic strains of Single Comb White Leghorn chickens and the relationship of egg shape to shell strength. Intl. J. of Poult. Sci. 3: 17-19.

Bain, M.M. (1990). Eggshell strength: a mechanical /ultrastructural evaluation. Ph.D. Thesis, University of Glasgow, UK.

Bain, M.M. (1992). Eggshell strength: A relationship between the mechanism of failure and the ultrastructural organization of the mammillary layer. Br. Poult. Sci. 33:303-319.

Bain, M.M. (2005). Recent advances in the assessment of eggshell quality and their future application. World’s Poultry Science Journal, 61:268-277.

Bain, M.M., MacLeod, N. Thomson, R. and Hancock, J.W. (2006a). Microcracks in eggs. Poult. Sci. 85: 2001-2008.

Bain, M.M., I.C. Dunn, P.W. Wilson, N. Joseph, B. De Ketelaere, J. De Baerdemaeker and D. Waddington. (2006b). Probability of an egg cracking during packing can be predicted using a simple non-destructive acoustic test. Br. Poult. Sci. 47:462-469.

Coucke, P.; Dewil, E.; Decuypere, E. and De Baerdemaeker, J. (1999). Measuring the mechanical stiffness of an eggshell using resonant frequency analysis. British Poultry Sci. 40: 227-232.

Darnell-middleton, S.L. (1999). Relationship between eggshell quality bone biology in the laying hen. Ph. D. Thesis, University of Glasgow, UK.

De Ketelaere, B.; Govaerts, T.; Coucke, P.; Dewil, E.; Visscher, J.; Decuypere, E. and De Baerdemaeker, J. (2002). Measuring the eggshell strength of 6 different strains of laying hens: techniques and comparison. British Poultry Sci. 43: 238-244.

El-Safty, S.A. (2004). Stepwise regression analysis for ultrstructural measurements of eggshell quality in two local breeds of chicken. Egypt. Poult. Sci. 24(1): 189-203.

El-Safty, S.A.; Fathi, M.M.; El-Attar, A.H. and Zein El-Dein, A. (2003). Laying performance of naked neck and normally feathered genotypes of chicken produced from different parental lines. Egypt. Poult. Sci. 23 (1): 169-181.

Etches, R. J. (1996) The egg. In: Etches, R.J.: Reproduction in poultry. CAB International, Wallingford, UK.

Fathi, M.M. (2001). Ultrastructural evaluation of eggshell quality produced from two different genetic groups of chicken. Egypt. Poult. Sci. 21(2): 263-275.

Fathi, M. M. and El-Sahar, E. A. (1996). Determining the strength of eggshell by using an appropriate apparatus and an equation to calculate egg surface depending on its dimensions. Egypt. Poult. Sci. 16(II): 285-303.

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Hamilton, R.M.G., Hollands, K.G., Voisey, P.W. and Grunder, A.A. (1979). Relationship between eggshell quality and shell breakage and factors that affect shell breakage in the field: a review. World’s Poult. Sci. J., 35: 177–190.

Hocking, P.M.; Fleming, R.; Channing, C.E.; Robertson, G.; Dick, I. and Wilson, S. (2001). Genetic variation for bone eggshell strength in commercial and traditional layers. Br. Poult. Sci. 42: S120-S121.

Hunton, P. (1995). Understanding the architecture of the eggshell. World’s Poult. Sci. J., 51: 140–147.

Hunton, P. (2005). Research on eggshell structure and quality: An historical overview. Brazilian J. Poult. Sci. 7:67-71.

Monira, K.N.; Salahuddin, M. and Miah, G. (2003). Effect of breed and holding period on egg quality characteristics of chicken. International Journal of Poultry Sci. 2: 261-263.

Nascimento, V.P.; Cranstoun, S. and Solomon, S E. (1992). Relationship between

shell structure and movement of Salmonella entertains across the eggshell

wall. Br. Poult. Sci. 33:37-48. National Research Council (1994). Nutrient Requirements of Poultry. 9th rev. ed.

National Academy Press, Washington, DC. SAS Institute (2000). JMP Statistics and Graphics Guide. Ver. 4, SAS Institute Inc.,

Cary, NC. 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.

Silversides, F.G., D.R. Korver and K.L. Budgell (2006). Effect of strain of layer and age of

photostimulation on egg production, egg quality and bone strength. Poult. Sci.

85:1136-1144.

Solomon, S.E. (1991). Egg and Eggshell Quality, Wolf Publishing Ltd., London. Stadelman, W. J.; Olson, V. M.; Shemwell, G. A. and Pasch, S. (1988). Egg and

Poultry Meat Processing. Ellis-Horwood Ltd, Chichester, UK.

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Table (1) Egg production parameters at sexual maturity for some local breeds.

B wt at sexual

maturity (g)

Age at sexual

maturity (d)

Egg wt (g) Egg no

(90 d)

Egg

mass

(g)

Breed

Bandara 1445.4 b

204.6 a 47.0

a 50.4 2370.1

Gimmiza 1565.7 a 181.6

b 47.4

a 56.0 2661.3

Mandara 1432.8b 172.3

c 45.1

b 54.6 2462.5

Pooled SEM ±22.67 ±1.37 ±0.36 ±1.62 ±76.69 Probability <0.0001 <0.0001 <0.0001 NS NS

a,b,c The means within columns with no common superscript differ significantly.

Data at sexual maturity for Matrouh breed were not available.

Table 2. Internal egg quality among breeds at 42 weeks of age.

Egg wt (g)

Shape Index

Yolk Index

Albumen%

Yolk %

Shell %

Haugh Units

Breed

Bandara 50.0 a 0.78 0.56

a 58.6

a 30.5

b 86.9

Gimmizah 50.4 a 0.76 0.53

ab 57.8

a 31.7

ab 82.9

Mandara 47.2 b 0.75 0.51

b 55.6

b 33.5

a 82.1

Matrouh 50.2 a 0.75 0.48

b 56.1

b 32.9

a 85.7

Pooled SEM

±0.60 ±0.0094

±0.0181

±0.72 ±0.51 ± ±1.61

Probability <0.0001 NS <0.023 <0.011 <0.005 NS

a,b The means within columns with no common superscript differ significantly.

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Table 3. Eggshell quality among breeds at 42 weeks of age.

Wet Shell %

Dry Shell %

Shell Thickness (mm)

Shell Breaking Strength (kg/cm2)

Shell Area (cm2)

Shell weight/un

it area (mg/ cm2)

S G

Breed

Bandara 10.6 b 9.5

a 0.354

ab 3.89

c 60.7 89.3 1.091

ab

Gimmizah 10.5 b 9.1

b 0.337

c 4.54

b 58.5 92.8 1.087

b

Mandara 11.5 a 9.7

a 0.351

b 5.90

a 59.3 91.9 1.090

ab

Matrouh 11.5 a 9.5

a 0.360

a 4.88

b 59.3 97.1 1.093

a

Pooled SEM

±0.19 ±0.15 ±0.005 ±0.35 ±0.97 ±1.8 ±0.0008

Probability <0.0001 <0.05 <0.02 <0.002 NS NS <0.0001

a,b,c The means within columns with no common superscript differ significantly.

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Table 4. Internal egg quality among breeds at 48 weeks of age. Breed Egg wt

(g) Shape Index

Yolk Index

Albumen%

Yolk %

Haugh Units

Bandara 51.6 b 0.78

a 0.49

a 56.9 32.0 83.4

Gimmizah 56.9 a 0.74

b 0.50

a 56.9 32.2 82.8

Mandara 52.4 b 0.76

ab 0.47

b 55.4 33.2 81.4

Matrouh 53.2 b 0.75

b 0.46

b 56.7 32.4 80.5

Pooled SEM ±0.69 ±0.0057 ±0.0071 ±0.56 ±0.51 ±1.35 Probability <0.0001 <0.0001 <0.01 NS NS NS

a,b The means within columns with no common superscript differ significantly. Table 5. Eggshell quality among breeds at 48 weeks of age.

Breed Wet Shell %

Dry Shell %

Shell Thickness (mm)

Shell Breakin

g Strength (kg/cm2)

Shell Area (cm2)

Shell weight/un

it area (mg/ cm2)

S G

Bandara 11.2 b 9.7 0.341

ab 4.42 57.5 100.9

a 1.093

Gimmizah 10.7 a 9.9 0.329

b 4.60 63.2 96.3

b 1.092

Mandara 11.5 a 10.3 0.351

a 5.21 59.8 100.9

a 1.094

Matrouh 10.8 a 9.6 0.349

a 4.38 61.0 95.2

b 1.090

Pooled SEM

±0.17 ±0.21 ±0.0051 ±0.45 ±1.28 ±1.9 ±0.0009

Probability <0.01 NS <0.04 NS NS <0.04 NS

a,b The means within columns with no common superscript differ significantly.

Table (6): Means SE of major mammillary layer measurements of eggshell for Matrouh, Bandara, Mandara and Gimmiza breeds.

Breed

Trait Matrouh Bandara Mandara Gimmiza Prob.

Confluence 2.6ab0.40 4.6a

0.97 1.0b0.00 3.4ab

0.97 0.03

Alignment 3.4ab0.74 4.6a

0.40 2.5b0.50 2.2b

0.49 0.03

Type Bs 3.01.09 3.80.80 2.50.50 1.80.48 NS

Erosion 3.8a0.80 3.0ab

0.00 1.0c0.00 2.2bc 0.49 0.01

Caps 4.2a0.48 4.6a

0.40 1.5b0.50 1.8b

0.49 0.0004

Type As 1.40.40 1.80.48 2.00.57 2.60.40 NS

Depression 3.2a0.80 2.2bc

0.48 1.3c0.25 2.8ab

0.48 0.05

Total Score 33.4a1.8 37.6a

1.47 23.3b1.25 27.4b

1.47 0.0001 a,b,c means with no common superscript in each row differ significantly.

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Fig. 1. Late fusion of mammillary columns and poor confluence in Bandara breed. Fig. 2. Type A mammillary body has no basal cap in Matrouh breed.

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Fig. 3. Confluent area leading to unable to define individual mammillary caps in

Mandara breed. Fig. 4. A bulk of secondary crystallization takes place among mammillary knobs

(cuffing) in Gimmiza breed.

USING SCANNING ELECTRON MICROSCOPY TO DETECT THE GENETIC DIVERSITY OF EGGSHELL QUALITY AMONG SOME...

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