Impacts of storage period and egg weight on hatching and growth performance of growing Japanese quails

Abstract

This investigation aimed to assess how Japanese quail hatchability, growth, and carcass traits were affected by quail egg weight, storage length, and their interactions. One thousand two hundred sixty eggs of the commercial Japanese quail were purchased, and the average age of the birds was 13 wk. Quail egg weights were divided into 3 groups using a 3 × 4 factorial design: small (< 11 g), medium (11–12 g), and large (> 12 g). Each group had four storage times (1, 4, 7, and 10 d) and held 105 eggs. The study used a storage room with 70% humidity and 18°C. There were 12 treatment groups. For the final 3 d of incubation, the eggs were positioned in a hatching machine after being incubated for 14 d at 37.6°C and 65% humidity. For the study, 540 one-day-old Japanese unsexed quail chicks were randomly chosen and placed in groups of 5 that resembled the distribution of eggs. Three duplicates (15 chicks each) made up each of the 4 storage periods that comprised the 180 birds. The findings showed that the percentage of hatchable eggs is significantly influenced by their weight and the length of storage; medium and heavy-weight eggs exhibited higher percentages of hatchability while holding for 7 to 10 d. However, no significant interaction was observed—additionally, heavy egg weight results in higher weight at different ages. Egg weight also significantly impacts chick weight at hatch, 3 wk, and 6 wk. Egg weight and storage time affect dressing and carcass measurement percentages. We can conclude that the best results in terms of hatch and post-hatch efficiency, as well as carcass characteristics, were obtained with medium or heavy quail eggs and storage times of either 1 d or 4 d.

INTRODUCTION

In the 12th century, Japanese quails (Coturnix coturnix japonica) were domesticated in Japan. Between the 1930s and the 1950s, quails with lines reared to produce eggs and meat migrated from Japan to Europe, America, and the Middle East (Ashok and Prabakaran, 2012). Quails are small birds that get reared for meat and egg production (Ahmad et al., 2018; Arunrao et al., 2023) and are characterized by a short production cycle, a higher egg-laying rate, and a healthier source of meat and egg products (Taha et al., 2019). The quality and storage factors of hatching eggs are crucial to the success of poultry production because they determine chicks' quality at 1-day-old and thereafter (Tainika et al., 2023). In most poultry company operations, such as laying hen breeders and broiler breeders, incubation performance and the factors influencing it are extensively investigated and studied (Iqbal et al., 2017; England et al., 2023).

Research studies on the variables affecting the success of other poultry species' egg incubation, such as partridges, ostriches, and quails, have, however, gotten less and very infrequent attention (Schmidt et al., 2009; Okur et al., 2018). Since the primary factor influencing egg size is the weight of the yolk sac that the chick keeps after hatching, the hatch weight and hatchability of chickens may be directly correlated with the eggs' weight (Rashid et al., 2005; King'ori et al., 2007). These effects are explained by the correlation between heritable parameters influencing various performance characteristics of broiler chickens and fertility, hatchability, and chick weight (King'ori, 2011). According to Havenstein et al. (1988), Japanese quail eggs ranged in weight between 8.31 and 13.00 g. Additionally, Alkan et al. (2008) demonstrated that hatchability values reduced when the egg's weight rose above 12 g, and the weight of Japanese quail eggs had an important effect on hatchability traits.

Regarding the amount of time hatching eggs ought to be kept before incubation, reports vary depending on the type of poultry and the production system. It is advised not to keep broiler and laying hen breeders' eggs for more than 7 d (Archer and Cartwright, 2012; Özlü, 2021). Research indicates that eggs lose a substantial amount of viability after 2 wk of storage (González-Redondo et al., 2023). Conversely, some bird species' eggs may withstand longer storage periods before incubation without deleterious impacts on their hatchability. In temperate parts of the world, there is a lot of research on the effects of storing eggs before incubation on hatchability and other properties of Japanese quail and other poultry eggs; however, in tropical and subtropical Africa, there is a dearth of such studies (Mani et al., 2008). The growth performance of quail chicks and hatchability performance was significantly impacted by the storage period and weight of the hatching egg (Petek et al., 2003). It has not been thoroughly studied how egg weight and storage duration affect quail hatchability effectiveness and afterward growth characteristics (Petek et al., 2003).

Thus, this study aimed to assess the impacts of egg weight and storage period of quail eggs and their interactions on hatchability traits, growth performance, and carcass traits of Japanese quails.

MATERIALS AND METHODS

The current study was conducted at the Poultry Research Farm, Faculty of Agriculture, Poultry Department, Zagazig University, Zagazig, Egypt. The study was validated and approved ethically with the code ZU-IACUC/2/F/95/2018 by the Faculty of Agriculture, Local Experimental Animal Care Committee, Zagazig University, Zagazig, Egypt.

Egg Source and Experimental Design

A total of 1260 hatching Japanese quail eggs were brought from a commercial breeding quail farm with an average age of 13 wk. In addition to being housed in cages, the quail breeders were given access to laying diets that included 2.50% calcium, 3,000 kcal/kg of metabolizable energy (ME), and 20% crude protein (CP).

A 3 × 4 factorial design was conducted, incorporating three groups of incubated quail egg weight categories (each comprising 420 eggs). The 1st group was categorized as small egg weights (S), < 11 g; the 2nd group was categorized as medium egg weights (M), < 11 g; and the third group was categorized as large egg weights (L), > 12 g, using (x̅ ±0.25) as the distribution of normality. Each category of egg weights was divided into 4 storage periods (1, 4, 7, and 10 d), each containing 105 eggs. Therefore, the study consisted of two main factors and their interactions (12 treatment groups). Table 1 presents the experimental design, containing the primary variables and the quantity of eggs used. The category groups were kept in a storage room at 18°C and 70% relative humidity and turned around twice daily until incubated. The hatching eggs were incubated at 37.6°C and 65% RH and turned automatically once every 2 h. For the first 14 d of incubation, eggs were transferred to the hatching machine under 37.5°C and 70% RH at the last 3 d of the incubation period.

Table 1.

Experimental design.

Main factors			No. of eggs incubation	No. of chicks
Egg weight category	Egg storage period
	Groups	Periods(days)
Light (< 11.0 g)	1	1	105	45
	2	4	105	45
	3	7	105	45
	4	10	105	45
Medium (11-12 g)	5	1	105	45
	6	4	105	45
	7	7	105	45
	8	10	105	45
Heavy (> 12.0 g)	9	1	105	45
	10	4	105	45
	11	7	105	45
	12	10	105	45

A total of 540 unsexed, 1-day-old Japanese quail chicks were randomly selected according to each group for the mentioned study and distributed in the same way as egg distribution, where each egg weight category chicks of 180 birds were divided into 4 storage periods (45 in each). Each storage period was composed of 3 replicates (15 chicks each). Chicks raised in appropriate pens throughout the experimental periods were housed in identical environmental, hygienic, and managerial conditions. Each replicate (15 birds) was housed in a wire cage (30 × 50 × 60 cm) with one deck during the experimental periods. Birds were exposed to 20 h of light per day. The birds were fed ad libitum and had access to fresh water during the trial.

Experimental Diet

The iso-caloric and iso-nitrogenous diet for growing Japanese quail was performed and used for all treatment groups. The experimental diet was formulated according to the nutrient requirements of growing Japanese quail as recommended by NRC (1994), whereas the birds were fed the diet from 1 d to 6 wk of age. The composition and analysis of the experimental basal diet are presented in Table 2.

Table 2.

Ingredient composition and nutrient levels of experimental diets (as-fed basis, %).

Ingredients	Percentages
Yellow corn	52.50
Soybean meal	38.20
Corn-gluten 60%	4.30
Cotton seed oil	1.60
Di-calcium phosphate	1.60
Limestone	1.10
NaCl	0.30
Premix 1	0.30
L-lysine	0.03
D-L methionine	0.07
Total	100.00
Nutrient levels2
CP %	24.15
ME kcal/kg	2,904.11
Ca %	0.87
P% (Avail, P.)	0.46
Lysine %	1.31
Methionine %	0.50
Met+ Cys. %	0.82

CP, crude protein; ME, metabolizable energy; P%, Av. Phosphorus.

¹Growth vitamin and mineral premix each kilogram contains of: vitamin A, 10,000 IU; vitamin D3, 2,750 IU; vitamin E, 30 IU; vitamin K3, 2 mg; vitamin B1, 1.5 mg; vitamin B2, 6 mg; vitamin B6, 3 mg; vitamin B12, 12 μg; nicotinic acid, 40 mg; pantothenic acid, 12 mg; folic acid, 0.8 mg; biotin, 0.2 mg; Zn, 100 mg; Mn, 150 mg; Fe, 95 mg; Cu, 10 mg; I, 1.25 mg; Se, 0.3 mg.

²Calculated according to NRC (1994).

Data Collection

Hatching Parameters

Following the end of the hatching process, the total number of non-fertilized eggs, eggs containing dead embryos, and hatched chicks were counted to calculate the following parameters:

$$\text{Scientific}\text{hatchability}\left(\text{hatchability}\text{of}\text{fertile}\text{eggs}\right)\%=\frac{Numberofhatchedchicks}{Totalnumberoffertileegg}\times 100$$

$$\text{Commercial}\text{hatchability}\%=\frac{Numberofhatchedchicks}{Totalnumberofeggset}\times 100$$

Chick Yield

After hatching, chicks were wing-banded and weighed individually to the nearest 0.1 g. Chick yield was calculated for each group according to the following equation:

$$\text{Chick}\text{yield}\%=\frac{\text{Average}\text{chick}\text{weight}}{\text{Average}\text{egg}\text{weight}\text{at}\text{setting}}\mathrm{\times }100$$

Performance Parameters

Hatching quail chicks were weighed at hatch, 3 and 6 wk of age, by an electronic balance to assess body weight (BW) to the nearest 0.1 g. Chicks' weight gain (WG) was calculated as the difference between 2 successive weights (0–3 and 4–6 wk). Also, WG was calculated for the entire rearing period (0–6 wk). The mortality percentage of growing quails was calculated for all experimental periods. Feed intake (FI) was calculated on a replicate basis and totalized for each group daily as the differences between feed offered and the remaining feed on the next day at the same time, then divided by the number of quails per each replicate/group at (0–3, 4–6 and 0–6 wk). Feed conversion ratio (FCR) was calculated as the number of grams of feed required to produce one gram of gain during a certain period (0–3, 4–6, and 0–6 wk).

Carcass Traits

Three birds from each replicate (36 birds per group) were randomly selected at the end of the trial period (6 wk of age), and the birds were fasted for 12 h before being slaughtered. After each quail was weighed, it was slaughtered with a sharp knife until it bled completely. After that, carcasses were plucked and then weighed. The carcass traits studied were carcass weight %, giblet weight % (liver, gizzard, and heart), and dressing weight percentages were calculated relative to the live weight of birds.

Statistical Analysis

Using SPSS (2014), data was analyzed statistically using a 3 × 4 factorial design based on Snedecor and Cochran (1982) model:

$${\mathrm{Y}}_{\text{ijk}}=\mu +{\mathrm{A}}_{\mathrm{i}}+{\mathrm{S}}_{\mathrm{J}}+\mathrm{A}*{\mathrm{S}}_{\text{ij}}+{\mathrm{e}}_{\text{ijk}}$$

Where: Y_ijk = an observation, µ = The overall mean,

A_i = Effect of egg weight categories (i = < 11 g, 11-12 g and >12 g),

S_J = Effect of egg storage periods (j = (1, 4, 7, and 10 d),

A*S_ij = The interaction between egg weight categories and egg storage period (ij = 1 to 12), and e_ijk = Random error.

Utilizing Duncan's New Multiple Range Test, disparities in means within the same factor (Duncan, 1955). An analysis of variance was carried out on hatchability percentages and mortality rates to determine if there were any differences between the groups in each study.

RESULTS

Effect of Egg Storage Periods

Table 3 illustrates data regarding egg weight during various storage times and their interactions. It was clear that the three categories of egg weight used in the experiment are significant, but egg weight is not different due to the storage period or interaction between weight and storage period.

Table 3.

Means of egg weight categories, egg storage periods used in this study and their interactions.

Items	Means of egg weight	Egg number
Egg weight category (g)
Light(L)	10.54 ± 0.06c	420
Medium(M)	11.53 ± 0.11b	420
Heavy(H)	12.43 ± 0.05a	420
P value	0.031	-
Egg storage periods (days)
1	11.50 ± 0.28	315
4	11.50 ± 0.29	315
7	11.51 ± 0.28	315
10	11.51 ± 0.29	315
P value	0.231	-
Interaction effects
Light
1 d	10.53 ± 0.29	105
4 d	10.54 ± 0.24	105
7 d	10.55 ± 0.14	105
10 d	10.54 ± 0.29	105
Medium
1 d	11.57 ± 0.37	105
4 d	11.55 ± 0.18	105
7 d	11.54 ± 0.30	105
10 d	11.51 ± 0.15	105
Heavy
1 d	12.39 ± 0.21	105
4 d	12.41 ± 0.25	105
7 d	12.45 ± 0.22	105
10 d	12.47 ± 0.19	105
P value	0.315	-

^abcMeans in the same column within each classification bearing different letters are significantly (P < 0.05) different.

Hatchability Percentages

The Table 4 findings demonstrated that the weight of the eggs had a significant (p < 0.01) effect on percentages of hatchability of total eggs set and hatchability of fertile eggs, where medium and heavy weight eggs had higher significant hatchability percentages compared to light egg weight. Concerning the egg storage period, percentages of hatchability of total eggs set and hatchability of fertile eggs were significantly impacted by the storage period, where eggs stored for 7 and 10 d had significantly decreased percentages of hatchability of total eggs set and hatchability of fertile eggs compared to eggs stored for 1 and 4 d. Regarding the effect of interaction between egg weight and the storage period, there was no significant impact of such interaction on percentages of hatchability of total eggs set, and hatchability of fertile eggs was recorded.

Table 4.

The hatchability percentage of the total eggs set as affected by quail egg weight categories, egg storage periods, and their interactions.

Items	H% of total eggs set	H% of fertile eggs set
Egg weight (g)
Light	63.54 ± 1.75b	74.27 ± 1.35b
Medium	70.00 ± 1.60a	77.55 ± 0.74a
Large	70.42 ± 1.71a	77.99 ± 0.89a
P value	0.024	0.031
Egg storage (days)
1	73.06 ± 1.30a	78.29 ± 0.97a
4	72.22 ± 1.47a	78.52 ± 0.89a
7	66.67 ± 0.83b	76.68 ± 0.73b
10	60.00 ± 1.56c	72.93 ± 1.55c
P value	0.001	0.002
Interaction effects
Light
1 d	68.33 ± 1.44	77.45 ± 4.24
4 d	67.50 ± 2.50	77.16 ± 2.57
7 d	64.17 ± 1.43	74.76 ± 1.53
10 d	54.16 ± 1.44	67.72 ± 1.04
Medium
1 d	75.00 ± 2.51	78.29 ± 3.65
4 d	74.17 ± 3.82	78.73 ± 2.96
7 d	67.50 ± 2.50	77.13 ± 0.65
10 d	63.33 ± 1.40	76.03 ± 2.64
Heavy
1 d	75.83 ± 1.44	79.13 ± 0.31
4 d	75.00 ± 2.50	79.66 ± 2.90
7 d	68.33 ± 1.44	78.14 ± 2.73
10 d	62.50 ± 2.51	75.05 ± 4.15
P value	0.451	0.412

^abcMeans in the same column within each classification bearing different letters differ significantly (P < 0.05).

Chick Yield and Body Weight

Table 5 displays the average chick yield at hatch and the weight of the quail at various ages. The average chick yields relative to the average egg weight set revealed that the medium egg weight produced a higher significant chick weight compared to light and heavy egg weight. The chick weight at hatch, 3 wk, and 6 wk of age were significantly impacted by egg weight; heavy egg weight produced higher significant chick weight at different ages compared to medium and light egg weight. In addition, medium egg weight produced significantly higher chick weight than light. Regarding the storage period and the interaction between egg weight and the storage period, there was no significant impact on chick yield or body weight of chicks at different ages.

Table 5.

Hatched chick yield and body weight of growing quail as affected by egg weight categories, egg storage periods, and their interactions.

Items	Hatched chick yield	Body weight
		At hatch	3w	6w
Egg weight category (g)
Light	68.52 ± 0.20b	7.21 ± 0.05c	83.70 ± 1.28b	171.61 ± 1.87c
Medium	70.80 ± 0.32a	8.17 ± 0.06b	87.90 ± 1.20a	179.45 ± 2.12b
Heavy	69.35 ± 0.35b	8.62 ± 0.04a	90.07 ± 2.15a	187.10 ± 1.35a
P value	0.001	0.001	0.003	0.002
Egg storage periods (days)
1 d	69.55 ± 0.37	7.98 ± 0.22	88.78 ± 3.48	181.61 ± 1.56
4 d	69.74 ± 0.52	8.02 ± 0.21	87.23 ± 2.26	180.40 ± 2.03
7 d	69.79 ± 0.43	8.04 ± 0.23	86.91±2.37	180.86 ± 3.14
10 d	69.15 ± 0.47	7.95 ± 0.20	85.98±2.59	175.67 ± 2.37
P value	0.146	0.214	0.542	0.651
Interaction effects
Small
1 d	68.56 ± 0.89	7.16 ± 0.19	85.04 ± 2.17	173.90 ± 2.13
4 ds	68.37 ± 0.84	7.20 ± 0.15	84.55 ± 2.06	172.47 ± 1.77
7 d	68.35 ± 0.42	7.21 ± 0.14	82.92 ± 2.28	171.29 ±1.16
10 d	68.80 ± 0.90	7.25 ± 0.27	82.30 ± 1.65	168.79 ± 1.51
Medium
1 d	70.86 ± 0.12	8.19 ± 0.28	89.45 ± 3.36	181.53 ± 4.15
4 d	71.51 ± 0.45	8.26 ± 0.14	87.60 ± 3.41	180.31 ± 2.54
7 d	70.79 ± 1.18	8.17 ± 0.26	87.83 ± 2.33	179.17 ± 2.98
10 d	70.05 ± 1.89	8.06 ± 0.13	86.73 ± 1.55	176.79 ± 3.72
Heavy
1 d	69.24 ± 0.11	8.58 ± 0.15	91.83 ± 3.49	186.40 ± 2.38
4 d	69.36 ± 1.06	8.61 ± 0.17	89.56 ± 2.83	188.43 ± 3.47
7 d	70.23 ± 0.31	8.74 ± 0.19	89.98 ± 2.57	192.12 ± 2.35
10 d	68.59 ± 1.32	8.55 ± 0.11	88.90 ± 2.85	181.45 ± 4.21
P value	0.845	0.315	0.451	0.645

^abcMeans in the same column within each classification bear different letters and differ significantly (P < 0.05).

Growth Performance

Table 6 yielded substantial effects on the daily BWG of Japanese quails at 1 to 3, 4 to 6, and 1 to 6 wk of age based on the egg weight category. At 4 to 6 and 1 to 6 wk of age, heavy egg weight resulted in higher significant body weight at 4 to 6 and 1 to 6 wk of age compared to medium and light egg weight chicks.

Table 6.

Body weight gain (g) of growing quail as affected by egg weight categories, egg storage periods, and their interactions.

Items	Body weight gain
	0-3w	4-6w	0-6w
Egg weight category (g.)
Light	76.50 ± 1.29b	87.91±1.47b	164.40 ± 1.70c
Medium	79.73 ± 1.30a	91.55 ± 1.73b	171.28 ± 1.48b
Heavy	81.45 ± 1.20a	97.88 ± 1.08a	179.33 ± 1.33a
P value	0.021	0.001	0.003
Egg storage periods (days)
1	80.80 ± 1.49	92.94 ± 1.71	173.74 ± 1.53a
4	79.21 ± 1.60	93.17 ± 2.01	172.38 ± 2.05a
7	78.87 ± 1.32	93.97 ± 1.67	172.84 ± 1.24a
10	78.02 ± 1.97	89.70 ± 1.53	167.72 ± 1.67b
P value	0.415	0.612	0.451
Interaction effects
Light
1 d	77.88 ± 3.77	88.85 ± 1.25	166.74 ± 3.82
4 d	77.34 ± 3.42	87.92 ± 3.06	165.26 ± 2.68
7 d	75.71±3.88	88.37 ± 3.17	164.08±1.92
10 d	75.05 ± 3.11	86.48 ± 2.84	161.54 ± 1.49
Medium
1 d	81.26 ± 3.09	92.08 ± 2.03	173.33 ± 4.69
4 d	79.34 ± 2.97	92.72 ± 3.83	172.06 ± 2.66
7 d	79.66 ± 2.27	91.34 ± 2.76	171.00 ± 4.92
10 d	78.67 ± 2.58	90.06 ± 3.82	168.73 ± 3.16
Heavy
1 d	83.25 ± 2.20	97.90 ± 3.74	181.11 ± 2.93
4 d	80.95 ± 2.83	98.87 ± 2.27	179.82 ± 5.64
7 d	81.23 ± 3.34	102.21 ± 2.82	183.44 ± 2.49
10 d	80.35 ± 2.05	92.55 ± 1.82	172.90 ± 3.32
P value	0.332	0.551	0.441

^abMeans in the same column within each classification bear different letters and differ significantly (P < 0.05).

Table 7 findings demonstrated egg weight categories affected the amount of feed that quail chicks consumed at 4 to 6 and 1 to 6 wk of age. Specifically, chicks from heavy eggs ate significantly more feed than those from medium and light egg weights. In the meantime, feed intake is unaffected (P > 0.05) by the storage duration of quail eggs or the interaction between storage duration and egg weight. Regarding feed conversion ratio (FCR) at 4 to 6 and 1 to 6 wk of age, chicks produced from medium egg weights exhibited the best FCR compared to chicks of heavy and light egg weights (Table 8). Quail egg storage duration and the interaction between egg weight and storage duration do not affect the FCR (P > 0.05).

Table 7.

Feed intake (g) of growing quail as affected by egg weight category, egg storage period, and their interactions.

Items	Feed intake g/bird
	1-d-3 w	4-6 w	1-d-6 w
Egg weight category (g.)
Light	219.38 ± 3.85	390.68 ± 4.95b	610.06 ± 7.85b
Medium	219.74 ± 5.90	380.37 ± 6.49b	600.11 ± 8.03b
Heavy	231.10 ± 4.21	432.84 ± 3.75a	663.95 ± 6.34a
P value	0.231	0.001	0.004
Egg storage period (day)
1 d	224.14 ± 6.81	400.26 ± 7.50	624.41 ± 9.22
4 d	220.82 ± 5.32	401.96 ± 5.62	622.78 ± 6.38
7 d	225.04 ± 4.73	408.88 ± 6.37	633.92 ± 7.20
10 d	223.62 ± 5.64	394.10 ± 4.36	617.72 ± 7.63
P value	0.512	0.612	0.418
Interaction effects
Light
1 d	222.50 ± 3.76	396.39 ± 6.11	618.89 ± 7.19
4 d	219.28 ± 3.87	389.13 ± 7.21	608.41 ± 5.32
7 d	218.97 ± 7.32	392.70 ± 4.37	611.67 ± 4.02
10 d	216.77 ± 6.13	384.51 ± 2.23	601.27 ± 6.11
Medium
1 day	220.16 ± 5.79	376.99 ± 4.31	597.15 ± 5.93
4 d	217.44 ± 5.17	383.48 ± 2.63	600.92 ± 7.38
7 d	220.88 ± 6.31	381.26 ± 6.29	602.14 ± 6.95
10 d	220.50 ± 4.08	379.75 ± 2.08	600.25 ± 5.67
Heavy
1 d	229.78 ± 3.68	427.41 ± 9.42	657.19 ± 7.61
4 d	225.75 ± 5.18	433.26 ± 5.45	659.01 ± 5.35
7 d	235.28 ± 6.43	452.67 ± 7.10	687.95 ± 6.21
10 d	233.61 ± 3.51	418.03 ± 4.38	651.64 ± 7.95
P value	0.236	0.614	0.124

^abMeans in the same column within each classification bear different letters and differ significantly (P<0.05).

Table 8.

The feed conversion ratio of growing quail as affected by egg weight categories, egg storage periods, and their interactions.

Items	Feed conversion ratio g feed/ g gain
	0-3 w	4-6 w	0-6 w
Egg weight category (g)
Light	2.87 ± 0.05	4.45 ± 0.15b	3.71 ± 0.07b
Medium	2.75 ± 0.09	4.16 ± 0.20a	3.50 ± 0.12a
Heavy	2.84 ± 0.11	4.43 ± 0.23b	3.70 ± 0.19b
P value	0.321	0.002	0.021
Egg storage periods (days)
1	2.78 ± 0.06	4.31 ± 0.07	3.60 ± 0.08
4	2.79 ± 0.05	4.32 ± 0.11	3.61 ± 0.09
7	2.85 ± 0.13	4.35 ± 0.10	3.67 ± 0.15
10	2.87 ± 0.09	4.40 ± 0.19	3.68 ± 0.20
P value	0.523	0.236	0.231
Interaction effects
Light
1 d	2.86 ± 0.11	4.46 ± 0.12	3.71 ± 0.10
4 d	2.84 ± 0.04	4.42 ± 0.17	3.68 ± 0.14
7 d	2.88 ± 0.09	4.45 ± 0.15	3.72 ± 0.05
10 d	2.88 ± 0.07	4.45 ± 0.09	3.72 ± 0.09
Medium
1 d	2.71 ± 0.13	4.09 ± 0.13	3.45 ± 0.07
4 d	2.73 ± 0.09	4.14 ± 0.11	3.49 ± 0.11
7 d	2.77 ± 0.05	4.17 ± 0.05	3.52 ± 0.06
10 d	2.81 ± 0.07	4.22 ± 0.08	3.56 ± 0.10
Heavy
1 d	2.76 ± 0.03	4.36 ± 0.09	3.63 ± 0.05
4 d	2.78 ± 0.05	4.39 ± 0.08	3.67 ± 0.08
7 d	2.89 ± 0.12	4.44 ± 0.11	3.75 ± 0.14
10 d	2.92 ± 0.08	4.52 ± 0.21	3.77 ± 0.20
P value	0.123	0.236	0.365

^abMeans in the same column within each classification bear different letters and differ significantly (P < 0.05).

Carcass Characteristics

Table 9 displays that the weight of the quail egg had a substantial (P < 0.05) effect on storage periods on dressing and carcass weight percentage due to quail egg weight categories and storage periods with no impact on their interaction. Medium and heavy egg weight produced birds with higher significant (P < 0.01) carcass percentages, while heavy egg weight produced quails with higher significant (P < 0.05) dressing percentages compared to the light egg weight category. Quails produced from eggs stored more than 7 d before incubation showed a significant decrease (P < 0.05) in carcass and dressing percentages compared to quails obtained from eggs stored up to 4 d.

Table 9.

Carcass traits of growing quail as affected by egg weight categories, egg storage periods, and their interactions at 6 wk of age.

Items	Carcass %	Giblets %	Dressing %
Egg weight category (g.)
Light	77.85 ± 0.41b	5.14 ± 0.14	82.99 ± 0.45b
Medium	78.93 ± 0.43a	4.84 ± 0.15	83.78 ± 0.41ab
Heavy	79.41 ± 0.35a	4.93 ± 0.13	84.35 ± 0.31a
P value	0.003	0.123	0.031
Egg storage periods (d)
1	78.60 ± 0.33a	5.06 ± 0.12	83.67 ± 0.37a
4	78.71 ± 0.44a	5.13 ± 0.15	83.43 ± 0.15a
7	77.39 ± 0.46b	4.71 ± 0.13	82.52 ± 0.39b
10	77.12 ± 0.38b	4.63 ± 0.19	82.09 ± 0.27b
P value	0.021	0.652	0.014
Interaction effects
Light
1 d	77.20 ± 0.37	5.16 ± 0.10	82.36 ± 0.27
4 d	78.11±0.21	5.02 ±0.17	83.13 ±0.25
7 d	77.39 ± 0.35	4.91±0.18	82.30±0.33
10 d	77.12 ± 0.19	4.83±0.21	81.95±0.22
Medium
1 d	79.60 ± 0.35	4.86±0.19	84.46±0.40
4 d	78.21 ± 0.51	5.17±0.11	83.38±0.21
7 d	78.39 ± 0.41	4.79±0.13	83.18±0.19
10 d	78.12 ± 0.42	4.72±0.20	82.84±0.23
Heavy
1 d	78.52 ± 0.37	4.86±0.21	83.38±0.27
4 d	78.41 ± 0.32	5.03±0.19	83.44±0.22
7 d	77.89 ± 0.25	4.31±0.14	82.20±0.31
10 d	77.34 ±0.41	4.93±0.18	82.27±0.28
P value	0.21 3	0.125	0.321

^abMeans in the same column within each classification bear different letters and differ significantly (P < 0.05).

DISCUSSION

The study indicated that hatchability percentages in both total and fertile eggs are highly influenced by egg weight, with higher percentages observed in medium- and heavy-weight eggs. Storage duration strongly impacts hatchability, with longer storage times leading to lower hatchability for both fertile and non-fertile eggs. Hatchability was not, however, considerably impacted by the combination of egg weight and storage duration. Our results concur with those of Taha et al. (2019), who found that a significant decrease in hatchability percentages due to the increasing storage period may be attributed to the reduction of internal egg quality parameters such as yolk and albumen parameters, which is responsible for optimum growth and development of the embryos till hatching.

Furthermore, as the storage period increased, the eggs lost moisture and CO₂ through eggshell pores, the yolk and albumen pH rose, and the vitelline and albumen height decreased. The timing of the carbon dioxide loss is crucial, as excessive carbon dioxide loss during egg storage raises the pH of the albumen, which could be detrimental to the viability of the developing embryo (Terčič and Pestotnik, 2016). The best hatchability percentages were recorded at 1 and 4 d storage, which agreed with those of Raji et al. (2014) who found that quail egg storage days had significantly (P < 0.001) affected hatchability (%) of fertile eggs and gave an estimate of 77.26, 73.53, 72.00, 79.07, 86.36, 56.16, 57.63, 34.29, 20.0 and 21.67% for the storage periods of 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10 d, respectively. Similarly, according to Mani et al. (2008), hatchability dramatically decreased after 9 d of storage. Furthermore, Nowaczewski et al. (2022) studied the impacts of egg size and storage period on the hatching performance of broiler breeder eggs. They found medium and larger eggs (62–71 g) with storage periods of up to 7 d had the best hatchability results.

Uddin et al. (1994) found that the hatchability of quail eggs was significantly (P < 0.01) higher with medium eggs. This could be attributed to the correspondingly lower death rates in germs and death in shells. Also, hatchability increased until a certain point and then decreased because the pre-incubation intervals were stored for longer periods (up to 7 d), according to Uddin et al. (1994). Furthermore, González-Redondo et al. (2023) found that quail eggs' longer storage times led to a noticeably lower hatchability percentage. Long-term egg storage decreased the hatchability of viable and set eggs and increased the percentage of embryonic deaths. Farooq et al. (2001) found that egg weight category had a significant (P < 0.01) effect on the hatched chick weight in Japanese quail, where 11.0 to 11.9, 12.0 to 12.9 and 13.0 to 13.9 g egg weight categories gave chick weights of 6.98, 7.56, and 8.39 g, respectively, which may be due to that the heavy eggs had a high amount of nutrients used in growing and developing quail embryos.

According to our findings, medium egg weights resulted in heavier chicks than light or heavy weights, with heavy weights producing heavier chicks at various ages. Goliomytis et al. (2015), hatchling weight decreased as egg storage length increased. This could immediately impact the embryo's growth and development (Christensen et al., 2002) or be connected to the increased water loss during storage (Goliomytis et al., 2015). According to Schmidt et al. (2009), various factors, including the incubator environment, genetics, length of storage, egg weight, and decreased weight in the incubator, can affect the hatching yield. Additionally, Salah Eldein et al. (2024) indicated the importance of medium egg weight for better hatchability, lower embryonic mortality, and optimal progeny growth performance in Japanese quail eggs.

Our findings partially corroborated those of Iqbal et al. (2016), who found that the increasing egg weight significantly increased the chick weight (P ≤ 0.05) with a positive correlation between chick weight and egg size at the setting but did not influence the chick yield. Later, Iqbal et al. (2017) reported that the egg weight of broiler breeders positively affected chick yield, chick weight, and chick length, but this positive effect was lost at altered stages of broiler growth. Dassidi et al. (2022) confirmed the positive effect of egg weight on the chick weight of ducklings when comparing medium and larger egg-weight ducklings with those of small egg-weight ducklings. Furthermore, Dudusola et al. (2021) indicated that the body weight of Japanese quail chicks from the day of birth to 6 wk of age had a favorable relationship with the mass of the egg placed in the incubator; medium (10–12 g) and heavy eggs (>12 g) produced quail chicks with significantly higher body weights up to 6 wk of age in comparison to light egg weight (<10 g).

Additionally, the findings were in line with those of Petek et al. (2005), who discovered that the egg weight categories had a substantial (P < 0.05) impact on the BW of developing Japanese quails at 42 d of age. The weight of the eggs in the light, <10.51, medium, 10.51–11.50, heavy, 11.51–12.50, and heaviest egg groups was 183.8, 187.4, 196.3, and 198.8 g, respectively. Petek et al. (2003) stored quail eggs before incubation for 1, 3, 5, and 7 d and reported no significant impacts of quail egg storage period on body weight up to 6 wk of age. In the meantime, Taha et al. (2019) discovered that extending the time that 2 quail strains' eggs were stored had an adverse effect (P < 0.05) on the BW and RGR% of the chicks. The findings could be attributed to the long storage period negatively affecting internal egg quality and yielding weak chicks with lower growth performance in advance.

According to our findings, the egg weight of Japanese quails had significant effects on both their daily BWG and FI. Compared to medium and light egg-weight chicks, heavy egg-weight chicks consumed more feed and had higher body weights. The length of egg storage or the relationship between egg weight and storage time did not affect FI. The best feed-to-weight ratio was found in medium-weight chicks. This result partially agreed with Copur et al. (2010), who found that while there was no statistically significant effect between the weights of the egg classification groups of <13.0, 13.0 to 14.0, and >14.0 g on average BWG for growing quail throughout the first 2 wk of life (P < 0.01), there was a substantial variance between the groups after 3 wk of age. Farooq et al. (2001) found that the egg weight category had a significant (P < 0.01) effect on the hatched chick weight in Japanese quail, which may be due to having heavy eggs with a high amount of nutrients used in growing and developing quail embryos. Regarding storage duration, quail chicks produced from eggs kept for up to 10 d had significantly less body gain than those raised from eggs kept for longer periods.

Taha et al. (2019) verified the findings by storing the eggs of two lines of Japanese quails for 0, 4, 7, and 10 d. They discovered that lengthening the storage period significantly reduced the BWG of the hatched chicks. This significant decrease in body weight gain due to the increasing storage period may be attributed to lowered egg quality and subsequent weak chicks with lower growth and livability performance. Additionally, Tona et al. (2001) found that a decrease in post-hatch performance, including relative growth, resulted from increasing storage duration and breeder age. However, Güvenc and Aygün (2022) discovered that the storage of quail eggs had no negative impact on the chicks' ability to grow. The results showed no interaction effect for egg weight categories and storage period of quail eggs on chicks' weight gain up to 6 wk of age.

According to Nasri et al. (2020a), the duration of storage of broiler breeder eggs had an impact on the FI and FCR of the chicks. According to Petek and Dikmen (2006) research, higher FCR was linked to longer egg storage times. However, several studies (Goliomytis et al., 2015; Okur et al., 2018) found that the length of time eggs were stored had no impact on the performance of the chicks.

Our findings revealed that dressing and carcass weight percentage are highly influenced by quail egg weight and storage times. The percentages of carcasses and dressing are higher in medium- and heavy-weight egg-weight birds, whereas they decrease in birds kept longer than 7 d. According to Abiola et al. (2008), medium-sized eggs of Anak broilers averaged 50 g. might be suitable for the setting to obtain the best result of some productive traits. Nonetheless, they suggested that the big eggs may have been chosen for a situation where special attention is paid to the traits of the carcass. Tufft and Jensen (1991) studied the effect of egg weight on chick performance and reported that as egg weight increased, fat retention was not affected. According to Mutibvu (2016), Venda chickens 8 to 13 wk old had no change in carcass weight or carcass parts for egg weights of less than 49 g, between 50 and 59 g, between 60 and 69 g, or ˃ 70 g. According to Nasri et al. (2020b), storage duration significantly impacts the heart's and the intestine's weights but not the percentages of the liver and gizzard. Also, Gao et al. (2024) found that Ovo probiotic application positively impacts hatchability, hatchling quality, and post-hatch growth, with a positive correlation with hatchling weight.

CONCLUSIONS

Based on the results obtained in this study, the percentage of hatchable eggs is significantly influenced by their weight and the length of storage. It can be concluded that medium or heavy quail eggs used and storage periods of 1 d or 4 d were preferable, as they gave the best results of hatch and post-hatch performance and carcass traits.