The egg shape index was found to be 75.44 in Table 2, which was slightly lower than the results of similar studies conducted in chukar eggs
(Song et al., 2000; Hashemipour et al., 2011; Çağlayan et al., 2014; Alkan et al., 2015; Aygün and Olgun, 2019). This difference could be attributed to the age of hens which was reported by
Han et al. (1991).
Addition of garlic and onion powder to chukar rations had no significant effect on egg shape traits (P>0.05). The results were in accordance with the studies of laying hens supplemented with 0.5% to 1%
(Yalçın et al., 2006) and between 3% and 5%
(Olobatoke and Mulugeta, 2011) garlic powder. Similarly,
Omer et al. (2019) reported adding onion or garlic powder to poultry ration wouldn’t change shape index of laying hens.
The effect of dietary garlic and onion powder supplementation on egg component ratios in Chukar partridge is shown in Table 3.
The proportion of egg components was determined as 57.01% albumen, 33.56% yolk and 9.43% shell, showing that it had been in the normal range
(Stadelman, 1995). There was no significant effect (P>0.05) among feeding groups in terms of the proportion of egg components (Table 3). The weight of egg components among treatment groups showed similar trend except the yolk weight (Table 4). Adding 1% onion powder to the ration increased yolk weights of chukar eggs (P<0.05) in agreement with the reports of
Damaziak et al. (2017) who found a positive increase in eggs of hens supplemented with onion powder. However,
Dosoky et al. (2021) reported insignificant effect of onion supplementation on egg yolk weight. Garlic supplementation of rations didn’t have any significant changes (P>0.05) in egg yolk weight which was in accordance with the reports of similar studies
(Chowdhury et al., 2002; Yalçın et al., 2006; Canoğulları et al., 2010; Olobatoke and Mulugeta, 2011). Numerous studies had varied results in egg weight change when the hens were supplemented with different amounts of garlic or onion powders
(Lim et al., 2006; Olobatoke and Mulugeta, 2011; Omer et al., 2019). In the study, we carefully collected the chukar eggs with the weights of 19-21 g which were in the range of chukar eggs
(Kırıkçı et al., 2018). Since possible inconsistent results might have occurred, there was no need to discuss the comparison of egg quality in this section.
The eggshell was thicker than those of the studies about chukars
(Song et al., 2000; Hashemipour et al., 2011; Alkan and Türker, 2021). Adding 1% rate of garlic and onion powder to the chukar rations did not affect eggshell traits significantly (P>0.05) (Table 5). There are numerous studies that reported laying hen or quail eggs supplemented with different amounts of garlic powder showed no significant differences in terms of egg shell quality
(Lim et al., 2006; Yalçın et al., 2006; Yalçın et al., 2007; Ao et al., 2010).
Damaziak et al. (2017) observed an increase of eggshell quality in the groups supplemented with onion extract. Dosoky
et al. (2021) reported no significant change of quail eggshell thickness when the ration was supplemented with onion powder.
The internal quality traits were found to be higher than those of other chukar partridges
(Song et al., 2000; Çağlayan et al., 2014; Alkan et al., 2015; Alkan and Türker, 2021; Çam et al., 2022). The main reason of this difference might be due to the time of egg quality assessment which was conducted in the first hours after collection of fresh eggs. There was no significant effect of 1% addition of garlic powder on the internal traits of chukar eggs (P>0.05) (Table 6). Similarly, various studies also showed that inclusion of different amount of garlic powder in the diets of different poultry species had no significant changes in egg internal quality
(Yalçın et al., 2006; Yalçın et al., 2007; Al Aqil, 2016). Even though no significant effect of internal quality were occurred among dietary groups, an increasing trend was seen in the groups supplemented with onion powder in this study (P<0.1). Likewise,
Damaziak et al. (2017) reported that adding onion extract in layer hens’ diet would improve the quality of eggs. However, quercetin, which is abundant in onion, had no significant effect on egg quality
(Liu et al., 2014).
Dosoky et al. (2021) reported the quality parameters of quail eggs weren’t significantly affected by dietary inclusion of onion powder (0.8%).
Omer et al. (2019) reported that there was no significant effect of adding dietary onion and garlic powder on Haugh unit of laying hens. But, in the same study, they also found a statistical effect in yolk index. The amount of feed additives in poultry ration might affect the success of the study. For instance, 1% addition of garlic and onion powder were implemented in this study.
Canoğulları et al. (2010) reported that internal qualities of quail eggs might be affected by more than 1% dietary garlic powder. This increment also agrees with the findings of
Olobatoke and Mulugeta (2011) who reported a significant increase in Haugh units of the eggs with the addition of 3% garlic powder. As we analysed the quality of eggs in the first month of the study, the duration of the study might change the results of egg traits. For instance,
Ao et al. (2010) couldn’t find any significant differences on dietary groups supplemented with different doses of garlic powder. But in the 5th week of the study period, they reported a significant change in the internal egg qualities of dietary groups supplemented with garlic powder.
Chemical compositions of the eggs are shown in Table 7. The chemical content of the chukar eggs was observed to be slightly lower for moisture content and higher for crude ash and protein content than those of chukars determined by
Song et al. (2000). Chemical composition of chukar eggs showed no significant difference among treatment groups (P>0.05).
As presented in Table 8, adding neither 1% garlic powder nor 1% onion powder to the diets significantly affected fatty acid composition of chukar eggs (P>0.05) in accordance with the results of
Ao et al. (2010). However,
Ao et al. (2010) reported decreasing of SFA and increasing of PUFA occurred when the amount of garlic additives was increased to the rate of 2% or 3%, which was beneficial to human health. The differences in implementing methods and duration of adding garlic and onion powder to the feeding groups might be responsible for the variations among the studies.