Veterinary World, EISSN: 2231-0916 Available at www.veterinaryworld.org/Vol.6/Sept-2013/2.pdf RESEARCH ARTICLE Open Access Effect of egg weight on hatchability and hatchling weight in Fayoumi,

Aim: An experiment was conducted to determine the effect of egg weight on hatchability, embryonic deaths and hatchling weight of three rural breeds (Fayoumi, Desi and crossbred (Rhode Island Red X Fayoumi) chickens. Materials and Methods: Three different egg weight groups classified into small: ( 45g) were used in the experiment. A complete randomized design was used for the experiment. Simultaneously quadratic type equation was used to determine the egg weight for optimum hatchability and hatchling weight. Results: Percentage hatchability of medium-sized eggs was higher (P < 0.05) than those in large sized eggs. Similarly, large–sized eggs had higher (P < 0.05) percentage hatchability than small sized eggs in all breeds. Hatchability percentage changed by ratio 0.4077 with one unit change in mean egg weight of Fayoumi. The hatchability changed by ratio 0.5488 with one unit change in egg weight of Desi. The hatchability changed by ratio 0.3767 with one unit change in egg weight of crossbred chickens. Mean hatchling weight in Fayoumi eggs changed by ratio of 0.6760; Desi eggs by ratio of 0.5955 and crossbred chicken eggs by ratio of 1.3613 with one unit change in mean egg weight. The overall mean hatchling weight as percentage of mean egg weight in case of Fayoumi was 67.10, in Desi 62.42 and 68.36 in case of cross birds. There was no evidence that hatchabilitypercentage increased with increase in egg weight in all the three strains of birds. Small-sized eggs had higher (P<0.05) embryonic deaths than those of medium and large-sized eggs in three breeds. Hatchling weight from large eggs were (P < 0.05) higher than those of small eggs in three breeds. Mean hatchling weight of Fayoumi changed by ratio 0.676 with one unit change in mean egg weight. In case of Desi chickens, mean hatchling weight changed by ratio 0.5955 with one unit change in egg weight. In case of crossbred chicken, mean hatchling weight changed by ratio 1.3613 with one unit change in egg. Conclusion: This study revealed that medium sized eggs were more appropriate for better hatchability percentage and lower embryonic deaths in three rural breeds. However, large sized eggs were suitable for better hatchling weight.


Introduction
is on an average 72% of egg weight [7]; 63.5% in Turkeys; 57.8% in Ducks; 58.9% in Goose; 61.9% in The avian egg is a biological system projected to Pheasant [8]. Hatchling weight is reported to account warrant the safety of the embryo and its successful for 87% of egg weight at the normal time for removal hatching into a fully developed chick [1]. Effect of egg from the hatcher [9]. Hatchling weight from dwarf weight on hatchability is an important economic trait in broiler breeders is reported to be 67.3% of egg weight domestic poultry. There are positive correlations compared to the significantly larger chicks (68.4% of among pre-incubation egg weight, hatchling weight egg weight) from a standard strain [10]. The time of and subsequent performance of different kinds of oviposition and age of parent have no significant effect poultry [2]. The size of day old chick is directly related on the egg weight: chick weight ratio when early and to the size of the hatching egg [3] and there is a late hatched chicks are weighed at the same time [11]. progressive increase in egg production related to The correlation of egg weight to hatchling weight is hatching egg weight [4].
generally very high ranging from 0.50 to 0.95 [12] and The heritability of 55% in egg weight serves as then decreases progressively until the chick is 8 to 12 determining factor for the strain of chickens to be weeks of age [13]. reared for hatching egg production [5]. The hatchling In broiler chickens, some studies showed a higher weight is usually in the range of 62 to 78% of egg hatchability for intermediate sized eggs compared to weight [6]. In case of Bob white quail, hatchling weight too small or too large eggs [6,14]. Another study with broiler chickens [15] showed that egg size typically affects hatching size in birds because the main effects of egg size lies in the mass of the residual yolk sac that the chick retains at hatching. However, there is a paucity of information on the effect of egg size on using Duncan's multiple range tests at the 0.05 level of hatchability and hatchling weight in indigenous significance [19]. The analyses were conducted using chickens. The egg production level of indigenous hens SPSS 15.0 software [20]. All comparisons were made within breeds, and the breeds were not compared with is normally low with only 40-60 small sized eggs each other. produced per bird per year under small holder The statistical model used was: management conditions [16]. Therefore, improving the Yij= ì + Ti + Óij hatchability of these eggs will help to improve the Where, productivity of these chickens.
Yij= the overall observation (hatchability, embryonic This study was conducted to determine any deaths, hatchling weight) deviation in hatchling weight as percentage age of egg ì= Population means weight and also any effects on hatchability of eggs of Ti= Effect of different egg weights (small, medium, rural breeds such as Fayoumi, Desi and crossbred large) (Rhode Island Red X Fayoumi) chickens.
2 Óij= Residual error with zero mean and variance ó

Materials and Methods
The responses in optimum hatchability and Ethical approval: Birds were maintained according to hatchling weight to egg weight were modeled using guidelines of Institutional Ethics Committee.
following quadratic equation: 2 In order to study effect of egg weight on hatchability Y = a+b x+b x 1 2 and hatchling weight trials were conducted using eggs Where, Y is optimum hatchability and hatchling of rural breeds such as Fayoumi, Desi and crossbred weight, 'a' is intersect, b and b is coefficients of 1 2 (Rhode Island Red X Fayoumi) chicken. Three quadratic equation, 'x' is egg weight. Fayoumi flocks were maintained at Breeding and

Incubation Division, Poultry Research Institute, Rawalpindi, Pakistan and included in the experiments
The effect of egg weight on hatchability were 37 weeks, 46 weeks and 55 weeks old. The trials percentage, embryonic deaths and hatchling weight are on Fayoumi breeding flock were conducted during summarized in Table-1.

October-December and March-April. The Desi birds
Though larger eggs from three breeds tended to included in trials were about 30 week old and crossbred record higher hatchability, these differences were not chickens (RIR X Fayoumi) were about 29 week old. statistically significant. Larger sample sizes are needed The trials on Desi and crossbred chickens were carried to test if these tendencies are significant. Percentage out during August-November. The birds included in all hatchability of medium-sized eggs was higher than trials were maintained on deep litter system in open those in large sized eggs. Similarly, large-sized eggs window houses. They were provided feed and water ad had higher percentage hatchability than small sized libitum. The birds were fed commercial breeder diet eggs in all breeds. The current findings are supported (16.50% CP, 2,800 kcal MEn/kg, 3.10% calcium and by some workers [21][22][23], who reported that inter-0.35% available phosphorus), formulated to meet or mediate sized eggs of ostrich and chickens had higher exceed NRC [17] requirements. The eggs collected hatchability. These results are divergent to the from each breeding stocks were grouped into 3 size observations made by some workers [24,25], who categories as follows: small (<41g), medium (41-45g) found that hatchability of eggs of ostrich, New and large (>45g), replicated three times (90 eggs/ Hampshire and Rhode Island Red breeds decreased replicate). The eggs collected from all the three with increasing egg weight. Similarly, another study breeding stocks were cleaned and fumigated and set in showed that large sized eggs of indigenous Venda th the incubator. On 7 day of incubation, eggs were chickens had higher hatchability than medium and candled and infertile or clear eggs were removed. On small sized eggs [26]. Researchers also found negative th the 18 day of incubation, the eggs were candled and correlations between egg weight and hatchability in those with evidence of living embryos were recorded crossbred chickens [3]. As indicated, in their studies for the different egg treatments and transferred to the heavier eggs resulted in lower hatchability as in the hatcher. The remaining eggs were candled and then current study. The reason for such differences in broken for microscopic analysis to distinguish the eggs hatchability might be due to breed differences. containing dead embryos from the infertile ones. At the The analysis of data for ascertaining the effect of st end of 21 day the hatch was taken out and observations egg weight on hatchability showed that hatchability with regard to number of normal chicks hatched, percentage changed by ratio 0.4077 with one unit hatchling weight and hatchability were calculated change in mean egg weight of Fayoumi in given set of using the formula described by Sahin and coworkers data (  (Table-2). There was, however, no evidence that deaths and hatchling weight were determined hatchability would increase with increase in egg following completely randomized design. When weight. The hatchability changed by ratio 0.3767 with differences were significant, means were separated Available at www.veterinaryworld.org/Vol.6/Sept-2013/2.pdf Veterinary World, EISSN: 2231-0916 one unit change in egg weight of crossbred chickens, in egg weight. The statistical analysis of data collected but there was no any significant relation of chick in case of Desi breeding stock was found to be similar weight with egg weight; as was also observed in to that of Fayoumi stock so far regression of mean Fayoumi and Desi eggs, which implied that hatchling weight on mean egg weight is concerned. In hatchability was mainly also affected by other factors case of Desi chickens, mean hatchling weight changed than egg weight. by ratio 0.5955 with one unit change in egg weight but Small-sized eggs had higher (P<0.05) embryonic there was no any significant relation of hatchling deaths than those of medium and large-sized eggs in weight with egg weight, which is contrary to that three breeds (Table-1). These results are in agreement Fayoumi chicken. In case of crossbred chicken, mean with the findings of some workers, who found that hatchling weight changed by ratio 1.3613 with one unit embryonic mortality rate in rock partridge and turkey change in egg weight but there was no any significant was decreased as the egg weight increases [27,28].
relation of chick weight with egg weight as was also This might be due to heavy eggs having more sufficient observed in Desi chickens. The positive correlation nutrients to support embryos compared to lighter eggs.
between egg weight and the weight of chick hatched In three breeds, hatchling weight from large eggs from it was reported by Garip and Dere [29] for were (P < 0.05) higher than those of small eggs. The Japenese quail, Çaðlayan and coworkers [27] for rock overall mean weight in Fayoumi eggs was 40.0 g which partridges, Raju and coworkers [30] for chicken and produced chicks whose average weight was found to be Saatc and coworkers [31] for geese. The positive 26.55 g which was 66.37% of egg weight. In case of correlation found between egg weight and the hatching Desi chickens mean egg weight was 45.0 g which weight indicated the advantage of initial bigger size produced chicks weighing 27.38 g on an average which egg at the time of setting. The hatchling weight as was 61.00% of egg weight and in case of crossbred function of egg weight was found to be consistent eggs weighed on mean 46.00 gm with chicks weighing regardless of strain difference. The results suggest 32.51 gm on an average which was 70.67% of egg selection of hatching eggs of proper size to produce weight. The hatchling weight in all the three rural quality chicks of better livability. breeds was found between 61 to 70% of egg weight Conclusions which is in agreement with commercial stocks as reported by some workers [6,8,10,12].
This study showed that medium-sized eggs were The data obtained of Fayoumi breeding stock was more suitable for good hatchability and lower embryonic subjected to statistical analysis and it was found that mortality in three rural breeds. However, large sized mean hatchling weight had linear relationship with egg eggs were suitable for better hatchling weight. weight ( Table 2). The regression analysis indicated that Authors' contributions mean hatchling weight changed by ratio 0.676 with one unit change in mean egg weight in given set of data.
AR, GA and MYA-Substantial contribution to conception The analysis further showed that there was strong and design of study. SHK-Acquisition of data and evidence that hatchling weight increased with increase drafted the manuscript, MJK and NI-analyzed and Available at www.veterinaryworld.org/Vol.6/Sept-2013/2.pdf