Dietary oils and other lipid sources are commonly incorporated into poultry diets because lipids provide approximately twice as much metabolizable energy (ME) as carbohydrates, making them an efficient source of dietary energy (Alhayaly et al., 2024). Numerous researchers observed no issues with the production efficacy of chickens when they were fed various dietary sources of n-3 polyunsaturated fatty acids (PUFAs) (Ebeid et al., 2008; Aziza et al., 2013; Saleh, 2013). In the poultry production sector, phytogenic feed supplements, which include their extracts and essential oils, are frequently used as alternatives to antibiotic growth enhancers (Saleh et al., 2019; Reda et al., 2024). Vegetable oils, including sunflower oil (SUNO), linseed oil (LINO), and canola oil (CANO), are valuable energy sources in laying-hen diets, providing highly essential fatty acids and digestible energy (Grobas et al., 2001). Their inclusion can improve feed utilization, egg yield, and egg weight while enhancing nutrient absorption and maintaining the composition of yolk fatty acids. Thus, appropriate vegetable oil supplementation may support productive performance, egg quality criteria, and sustainable production of laying hens (Gao et al., 2021).

The supplement of LINO in the feed considerably reduced the concentrations of cholesterol and triglycerides, as reported by Saleh et al. (2013) and Ibrahim and Abdul-Rahman (2024). Additionally, Promila et al. (2017) demonstrated that hens fed diets having 2.5 % linseed oil had significantly greater hen day egg production (P < 0.05) than those fed a maize-based diet (control) and those of the other treatment method. In the same context, Celebi and Utlu (2006) reported that the egg production of chickens that were fed a diet with 4 % flaxseed oil was elevated (P ≤ 0.05). The supplementation of linseed and linseed oil in the feed of poultry led to a 4 % rise in egg production (Augustyn et al., 2006). Conversely, Skřivan et al. (2008) additionally noted a reduction in egg production in chickens that were fed 3 % flaxseed oil. According to different studies, the link between the concentration of cholesterol and unsaturated lipid concentration in the feed must be taken into consideration when estimating the cholesterolgenic impacts of meals rather than only their cholesterol concentration (Hopkins, 1992; Alagawany et al., 2021). The liver is the most important site of cholesterol production in laying hens, where it is integrated into very low-density lipoprotein (VLDL) and vitellogenin (VTG) particles. These are subsequently discharged into the blood stream and absorbed by the developing oocytes through endocytosis. Subsequently, VLDL and VTG are included in the yolk, which accounts for a significant portion of the yolk cholesterol (Elkin, 2006). Linseed oil contains the highest amount of n-3 PUFAs, specifically alpha-linolenic acid (ALA) at roughly 45 % to 60 % of total fatty acids, followed by canola oil at around 8 % to 10 %, while sunflower oil contains negligible to very low amounts (Ghobadi et al., 2019; Alagawany et al., 2021; Marino et al., 2024). Therefore, poultry diets could be enriched by linseed oil (LO) and canola oil (CO), and the yolk will be enriched with ALA and docosahexaenoic acid-DHA (Alagawany et al., 2019; Abo Egila et al., 2023).

Vitamin E serves as the principal antioxidant agent in egg yolk lipids, efficiently halting the lipid peroxidation process by stabilizing the process of lipid peroxides via interaction (Domínguez et al., 2019). Nemati et al. (2020) have expressed that the nutritional value of poultry meat is improved, and growth performance is improved with additional dietary vitamin E in chickens' diets. This is especially relevant regarding the constituents and lifespan of fatty acids. Łukaszewicz et al. (2007) evaluated the impression of vitamin E and organic selenium meal administration on the sensory characteristics and chemical composition of Japanese quail breeder (Coturnix japonica) eggs, and they stated that the lipid content in eggs and the cholesterol concentration in yolks are reduced as a result of the addition of vitamin E and selenium into the feed of Japanese quails, while the levels of selenium, protein, and antioxidant properties are increased. Additionally, the administration of 60 IU kg⁻¹ of vitamin E improves feed consumption rate; egg production percentage; and egg qualities, such as vitelline membrane strength, egg weight, and Haugh unit (Kirunda et al., 2001). A remarkable correlation exists between Se and vitamin E (VE) in terms of their protective effects on cells against free radical damage (Surai, 2002a). Additionally, the absorption of vitamin E in birds is impeded by selenium deprivation, which indicates the intricate relationship between their metabolisms (Skřivan et al., 2008). Vitamin E percentages in the plasma, egg yolk, and poultry meat are also increased by dietary selenium (Surai, 2002b). We hypothesized that different dietary sources of vegetable oils would differentially influence the productivity and egg yolk lipid profile of quail breeders and that supplementation of vitamin E would modify or improve these responses depending on the kind of oil used. This experiment was performed to determine the probable impact of sunflower oil (SUNO), linseed oil (LINO), and canola oil (CANO) with or without vitamin E treatments on the productivity parameters and egg yolk lipid metabolism of quail eggs.

The nearly identical egg production in Japanese quail breeders with various dietary supplementations may be attributed to the fact that all feed was maintained to have the same percentage of energy and protein, as well as being similar with regard to other essential nutrients (Ebeid et al., 2011). Vegetable oils including SUNO, LINO, and CANO can affect the productivity of laying hens, primarily through their fatty acid profiles; SUNO, rich in linoleic acid, supports yolk n-6 PUFA deposition and energy supply; LINO, rich in α-linolenic acid, improves yolk n-3 PUFA and enhances the ratio of n-6 : n-3; and CANO provides moderate PUFA and oleic acid. These oils may also modulate antioxidant defenses and lipid metabolism (Mazalli et al., 2004; Saleh et al., 2013).

These outcomes align with the outputs of Silke et al. (2008), who asserted that the egg production of hens that were fed either 10 % or 20 % flaxseed in their diets was not substantially different (P > 0.05). Additionally, according to the findings of Jalil and Yurtseven (2023), no considerable variation in egg production was observed across the different concentrations (P > 0.05). The highest average total number of eggs laid over 14 d occurred with the application of moringa leaf, whereas the lowest was observed with canola seed powder. In contrast, Celebi and Utlu (2006) evidenced a significant enhancement (P < 0.05) in egg production among chickens supplemented with linseed oil. However, another study showed a decreasing in egg production in chickens that were fed diets supplemented with linseed meal or linseed oil (Švedová et al., 2008).

These discoveries align with those of Golzar Adabi et al. (2016), who determined that the egg weight and laying rate were not substantially impacted by canola and linseed oils (P > 0.05). Zeweil et al. (2013) discovered that the addition of linseed meal into the feed did not produce a statistically substantial variation in the egg-laying rate, egg weight, and egg mass of laying Japanese quails when contrasted with laying hens that were fed a diet devoid of flaxseed meal. Throughout the egg-laying phase of the Japanese quail, natural supplements, including linseed oil, canola oil, and vitamin E, had a beneficial impact on the antioxidative qualities of blood and egg yolks, as well as efficacy and lipid metabolism, as detailed by Abo Egila et al. (2023). Vitamin E may be capable of inhibiting oxidative damage and initiating the release of the yolk precursor protein, which is crucial for the development of eggs, by maintaining the integrity of the liver cells and other organs activity (Abd-El-Maksoud, 2006). In addition, Omar (2014) discovered that the total lipids, triglycerides, and cholesterol concentrations of egg yolks in laying Japanese quails at 24 weeks of age were substantially reduced by the addition of linseed and vitamins A and E into the feed. Behesti Moghadam et al. (2019) observed that the total lipid content of eggs was not influenced by the heating of flaxseed or enzyme supplementation. The discovery that linseed oil augmented egg production in stressed chickens was intriguing. In hens, the hypothalamic–pituitary–gonadal gland regulates the egg-laying process, which is stimulated by the gonadotropin-releasing hormone (Mishra et al., 2019). With the oral addition of essential oil extracted from ginger rhizomes to Japanese quails, Tchoffo et al. (2019) discovered that yolk cholesterol was reduced. The egg yolk accumulates fatty acids from vegetable oils, which leads to lipid oxidation, hydrolysis, and polymerization (Wang et al., 2017). Consequently, sensory properties such as taste, flavor, color, and texture are impacted (Brelaz et al., 2019). Conversely, stress exacerbated lipid oxidation (Eid et al., 2008), which could potentially modify sensory characteristics. Vitamin E and selenium may exert a protective effect on lipid peroxidation due to their antioxidant properties in glutathione peroxidase activity. In the cytosol and mitochondrial matrix, the reduced form of GSH-Px contributes to the detoxification of pro-oxidants by reducing hydrogen peroxide and lipid hydroperoxide (Bansal and Kaur, 2005). Mohiti-Asli et al. (2008), in accordance with our data, observed that the elevated MDA content in eggs maintained in an incubator and at ambient temperature can be alleviated by maternal dietary administration of selenium and vitamin E.

To our knowledge, no data exist demonstrating the contrary impacts of stocking density stress on the sensory characteristics of eggs. Behesti Moghadam et al. (2019) stated that the levels of thiobarbituric acid reactive compounds in eggs produced from layers fed heated linseed combined with vitamin E (60 °C for 8 h) were substantially lower than those in eggs produced from layers fed raw flaxseed with vitamin E (P < 0.05). Upon 10 d of storage at room temperature, Faitarone et al. (2016) noted a significant rise in yolk lipid oxidation. The eggs from layers fed on a diet without oil administration or supplied with 2.5 % soybean oil had a reduced level of yolk lipid oxidation compared to those from layers fed on diets treated with 5 % linseed oil and 2.5 % canola oil plus 2.5 % soybean oil. Nonetheless, these eggs exhibited no substantial differences. Giampietro et al. (2008) confirmed that the oxidation of lipids in egg yolks escalates with the age of the egg. The authors recorded thiobarbituric acid reactive (TBA) substance levels of 0.1343 in raw eggs, which rose to 0.1698 after 7 d of storage and to 0.2138 after 14 d of storage. Our findings are at odds with those of Gómez (2003), who observed that the lipid oxidation levels of the eggs of hens supplemented with diets with 5 % flaxseed oil were considerably higher than those of chicken fed diets with no oil administration. The researcher posits that the increased levels of oxidation of yolk lipids are due to the increased levels of unsaturated linolenic acid. Roux et al. (2011) demonstrated that omega-3 enhancement elevates MDA levels in the absence of vitamin E supplementation. Nevertheless, the MDA values remained consistent with those of the control group, which contained no omega-3 or vitamin E supplementation. This was because of the addition of vitamin E, and MDA levels increased during refrigerated storage. Moreover, the characteristics under investigation exhibited a substantial interaction effect, and the groups that were fed linseed or canola and treated with vitamin E recorded the highest levels of MDA at 15 and 20 weeks of age, as well as after 15 and 30 d of storage in the refrigerator.

The lipid oxidation constancy of fresh quail eggs is generally affected by various supplements that are included in the diet during the egg's storage in the refrigerator under the circumstances of the current trial. The existing conclusions agreed with those of Narciso-Gaytán et al. (2010) to a lesser or greater extent. They reported that the high supplemented level showed lower (P ≤ 0.05) malonaldehyde values than the control treatment. In conclusion, the lipid oxidation stability of chicken meat is influenced by the lipid source and vitamin E level included in the diet upon storage time and processing of the meat.

Tchoffo et al. (2019) recently discovered that the concentration of yolk MDA decreased substantially (P < 0.05) as the dose of ginger essential oil increased. Unlike MDA, the GPx activity status increased linearly and substantially (P < 0.05) as the essential oil levels increased. The MDA is a significant endogenous lipid peroxidation product; consequently, the degree of fat peroxidation by reactive oxygen species (ROSs) may be observed in MDA concentrations (Jiang et al., 2007). Nevertheless, the concentration of antioxidants in developing embryonic tissues is increased by a diet that contains antioxidant properties, which, in turn, decreases their liability with regard to lipid peroxidation (Surai, 1999). Consequently, the rate of embryonic mortality is reduced. In the present study, ginger was found to increase the antioxidant capability of birds against ROSs and to decrease plasma MDA levels in comparison to the control group, as noted by Akbarian et al. (2011). Previously, Tchoffo et al. (2019) discovered that the GPx action was amplified linearly and substantially (P < 0.05) as the essential oil levels increased. Relative to the control, the CAT action was enhanced by ginger essential oil at all chosen dosages. Nevertheless, this rise was statistically significant (P < 0.05) only at 100 µL kg⁻¹ body weight. Additionally, the MDA concentrations in the egg yolk were slightly lowered by the inclusion of 800 mg vitamin E in the diets of laying hens by Tadesse et al. (2023).

The information gained from this research demonstrated that the combined use of flaxseed oil, canola oil, and vitamin E had positive effects on the productivity, lipid metabolism, and antioxidative properties of egg yolks in Japanese quail breeders (Coturnix japonica) within the laying period.