Kabir et al. 2012 UJZRU

ISSN 1023-6104 © Rajshahi University Zoological Society Univ. j. zool. Rajshahi Univ. Vol. 31, 2012 pp. 85-87 http://journals.sfu.ca/bd/index.php/UJZRU Scientific Note Egg morphometric analyses in chickens and some selected birds Md. Ashraful Kabir1, M. Saiful Islam* and Ripon Kumar Dutta Department of Zoology, University of Rajshahi, Rajshahi 6205, Bangladesh; 1Present address: Department of Biology, Holy Land College, Dinajpur 5200, Bangladesh; *Corresponding author (email: saifulzoo@yahoo.co.uk). Morphometrics in general refers to measurements of the body parts. The knowledge and information on morphometric parameters is therefore essential for understanding an animal and its reproductive biology in particular (Danilov, 2000). Egg morphometric parameters such as egg weight, egg width, albumen and yolk weights are very important in poultry because these factors influence egg quality and grading (Farooq et al., 2001), reproductive fitness of the chickens and embryonic development (Onagbesan et al., 2007). Effects of feed (Shapira, 2010) and housing system (Wang et al., 2009) on egg composition and its quality have been reported. Internal egg quality parameters such as albumen weight and yolk weight are very important from nutritional and cholesterol content for human consumption (Sparks, 2006). Egg characteristics of Fayoumi (Islam, 2005), broiler chickens (Mamun, 2005) and indigenous fowl (Sarker, 2006) have previously been reported. In recent years egg quality traits of various chicken breeds (Islam & Dutta, 2010; Jones et al., 2010; Momoh et al., 2010) revealed results that are important to poultry breeders. Here we report a detailed account of egg morphometrics from six available chicken breeds and five other bird species. Experimental: Eggs from breeder hens of an indigenous (non-descriptive, Deshi), five purebred exotics viz., Cobb-500, RIR, ISA Brown, ISA White and Fayoumi, and a crossbred called Sonali (derived from RIR♂ × Fayoumi♀) were collected for this study. Moreover, eggs from five selected pet birds namely goose, duck, pigeon, dove and quail were also collected. A total of 120 fresh eggs (12 birds × 10 replicates each) were collected for estimating egg quality traits viz. egg length (EL in cm), egg width (EW in cm), egg volume (EV in cm3), gross egg weight (GW in g) and shell weight (SW in g). In addition, four internal egg quality traits viz. shell index (SI=EW÷EL×100), shell ratio (SR=SW÷EW×100), yolk weight (YW in g) and albumin weight (AW in g) were taken into account. The eggs were numbered first and then weighed on an electronic balance to determine their weights. Subsequently, EV was determined using the formula, EV= π × EL × EW2/6 (cm3). Each egg was broken on a table and its contents poured into a plate or small pot. Then the yolk was separated from the albumen with the help of a spoon and weighed. Moreover, the phenotypic associations between the relevant external and internal egg quality traits were determined by Karl Pearson’s product moment co-efficient of correlation (r). Mean, standard deviation (SD), analysis of variance (ANOVA), least significant differences (LSD) and r values were computed using the SPSS (version 11.0 for Windows). Data on various egg morphometrics and external and internal egg quality traits were subject to these statistical procedures to detect the significant differences between the genetic groups of chicken under study. Egg morphometric parameters in chickens: It is apparent from the results presented in Table 1 that the parameters like EL, EW, EV, GW, SW and AW were found to be the highest in ISA Brown and the lowest in the indigenous chickens. This trend was altered for YW, SI and SR traits where the highest values were recorded respectively in Cobb 500, Cobb 500 and RIR, whereas the indigenous, ISA White and ISA White showed the lowest values. A descending order of ISA Brown > ISA White > Cobb 500 > Fayoumi >RIR > Sonali > indigenous was obvious for EV. Depending on GW, the chicken breeds could be arranged in a descending order of ISA Brown > Cobb 500 > ISA White > Fayoumi >RIR > Sonali > indigenous. The AY of the chickens was recorded as follows: ISA Brown > Cobb 500 > ISA White> Fayoumi > RIR > Sonali > indigenous while the YW was recorded as Cobb 500 > ISA White> ISA Brown > Fayoumi > Sonali > RIR > indigenous. One-way ANOVA demonstrated that all the egg morphometric parameters varied significantly among the chicken breeds (P<0.001) except for EL (F6, 63= 1.24; P>0.05). Egg morphometric parameters in other birds: In birds other than chickens, goose had the highest values for EL, EW, EV, GW, SW, AW and YW, whereas quail and pigeon attained the highest values for SI and SR, respectively. On the other hand, quail (EL and AW), dove (EW, EV, GW and SW), pigeon (YW) and goose (SI and SR) showed the lowest values for the parameters in parentheses (Table 1). On the basis of EV and GW, a descending order of goose > duck > pigeon Kabir et al. 86 > quail > dove was recorded for each parameter. On the other hand, the sequences of AW and YW were goose > duck > pigeon > dove > quail, and goose > duck > quail > dove > pigeon, respectively. Unlike chicken breeds, one-way ANOVA revealed highly significant variations among the five bird species under study (P<0.001). Table 1. Egg morphometric parameters in chickens and some other birds Breeds Indigenou s Cobb 500 ISA Brown ISA White RIR Fayoumi Sonali Goose Duck Pigeon Dove Quail EL EW EV GW SW AW YW SI SR 4.59 a ±0.47 5.86 ±0.15a 5.93 ±0.54a 5.90 a ±0.14 5.11 ±0.15a 5.06 ±0.23a 4.96 ±0.14a 8.80 ±0.19a 5.87 ±0.17b 3.82 ±0.19c 3.26 ±0.08d 3.15 ±0.09de 3.56 ±0.19a 4.09 ±0.17bh 4.56 ±0.14c 4.25 bd ±0.10 3.83 ±0.07ef 3.92 ±0.13fgh 3.77 ±0.09fg 5.96 ±0.19a 4.07 ±0.09b 2.73 ±0.12c 2.30 ±0.08d 2.41 ±0.09de 30.72 ±5.81a 51.45 ±5.18b 62.01 ±4.80c 55.78 bdh ±2.58 39.26 ±2.20ef 40.73 ±3.31f 36.94 ±2.55efg 63.91 ±3.57a 51.42 ±2.85b 14.97 ±1.97c 9.05 ±0.84cd 9.59 ±0.81ce 20.20 ±4.76a 56.20 ±1.62b 57.50 ±2.72bc 53.90 bd ±2.64 28.80 ±0.80e 38.00 ±3.30f 26.60 ±4.81eg 66.30 ±3.34a 53.50 ±5.76b 11.70 ±0.82c 9.40 ±0.52cd 10.90 ±1.73ce 4.20 ±1.69a 9.20 ±0.92b 10.20 ±1.14bc 8.50 bd ±1.51 6.70 ±0.68e 8.60 ±0.84bf 5.10 ±2.18ae 20.00 ±1.25a 9.00 ±2.16b 2.40 ±0.52c 1.60 ±0.52cd 2.20 ±0.63ce 8.10 ±2.08a 32.00 ±2.40b 35.50 ±2.17c 31.70 bd ±1.4 13.30 ±1.25e 19.40 ±2.01f 12.50 ±3.21eg 81.60 ±1.35a 28.70 ±3.02b 6.30 ±0.68c 4.30 ±0.48cd 3.70 ±0.68def 7.90 ±2.03a 15.00 ±2.87b 11.90 ±1.10ce 13.70 bde ±2.67 8.80 ±1.40a 10.00 ±1.63ac 9.00 ±1.33a 64.70 ±1.83a 15.80 ±2.53b 3.00 ±0.82c 3.30 ±0.48cd 5.00 ±1.56ce 78.10 ±7.11a 69.79 ±1.95c 79.90 ±2.83a 72.08 c ±2.70 74.99 ±1.93b 77.64 ±4.80a 76.04 ±2.15b 67.57 ±1.16c 69.36 ±1.51c 71.50 ±1.64b 70.55 ±1.49b 76.54 ±3.04a 20.17 ±4.65b 16.35 ±1.35c 17.78 ±1.53c 15.75 c ±2.59 23.25 ±2.09a 22.71 ±2.24a 18.94 ±6.00b 12.02 ±0.62c 16.74 ±3.34b 20.69 ±5.18a 15.78 ±4.96b 19.11 ±6.14a EL= egg length; EW= egg width; EV= egg volume; GW= gross egg weight; SW= shell weight; AW= albumen weight; YW= yolk weight; SI= shell index; SR= shell ratio. Figures (mean ± SD values) followed by different superscripts for each parameter in the same column (chickens and other birds considered separately) differ significantly by LSD (P<0.05). Associations between egg morphometric parameters: The GW was significantly correlated with EV in indigenous (r= 0.88; P<0.001) and ISA Brown (r= 0.72; P<0.001), with SW in indigenous (r= 0.88; P<0.001) and Cobb 500 (r= 0.72; P<0.05), with AW in indigenous (r= 0.84; P<0.01), ISA Brown (r= 0.77; P<0.01), Fayoumi (r= 0.90; P<0.001)and Sonali (r= 0.81; P<0.01), with YW in indigenous (r= 0.75; P<0.05), Cobb 500 (r= 0.69; P<0.05), ISA White (r= 0.74; P<0.05), Fayoumi (r= 0.64; P<0.05) and Sonali (r= 0.71; P<0.05), with SI in ISA White (r= -0.78; P<0.01) and Fayoumi (r= 0.65; P<0.05); and with SR in indigenous chickens (r= 0.63; P<0.05) only. In birds other than chickens, significant correlations were found to exist between GW and EV for goose (r= 0.91; P<0.001), duck (r= 0.83; P<0.01) and pigeon (r= 0.66; P<0.05); between GW and SW and GW and AW for goose (r= 0.64, 0.67 and 0.89, respectively), duck (r= 0.66, 0.69 and 0.89, respectively) and dove (r= 0.67, and 0.80, respectively); between GW and YW for goose (r= 0.89; P<0.001), duck (r= 0.89; P<0.001), pigeon (r= 0.66; P<0.05) and quail (r= 0.82; P<0.01); and between GW and SR for dove only (r= 0.73; P<0.05). All other correlations between the egg parameters in chickens and other bird species were statistically insignificants. Economically important egg morphometric parameters such as weight, size, albumen and yolk contents are quantitative traits that show continuous variability (Chatterjee et al., 2007; Islam & Dutta, 2010). It is also an established fact that the weight of an egg is a direct proportion of shell, albumen and yolk that it contains and this varies significantly between breeds or strains of the bird species (Jones et al., 2010; Momoh et al., 2010). The present results lend support to the findings of Yeasmin & Howlider (1998) and Islam Egg morphometric analyses in chickens and some selected birds (2006) for indigenous, Nahar et al. (2007) for broiler, Islam & Nahar (2008) for White Leghorn, RIR and indigenous, and Miazi (2008) for Fayoumi and Sonali chickens. Internal egg parameters such as AW and YW are very important from nutritional and health viewpoints (Sparks, 2006). In this regard, ISA Brown eggs showing the highest albumen contents (35.50±2.17g) and indigenous eggs showing the lowest yolk content (7.96±2.03g) could be considered preferable. Significant correlations between GW and various external and internal egg parameters of the present study agree with Pohle & Cheng (2009) and Momoh et al. (2010). But unfortunately, owing to scarcity of experimental data on egg morphometrics of such birds as goose, duck, dove, pigeon and quail, the present results could not be compared. Conclusions: Chicken eggs contribute substantially to the human nutrition and so their dietary profile including lipid, cholesterol and antioxidant contents are particularly important. In addition, because yolk weight is related to the amount of cholesterol, choice for the nutritionally potential and healthier eggs is a matter of considerable concern, especially to patients suffering from cardiovascular diseases, oxidative stress, endothelial dysfunction and inflammatory syndromes. 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