Poultry production is presumably the most rapidly growing, adaptable, and profitable of all livestock sectors expanding in both developed and developing countries (1, 2). Poultry meat is widely accepted and consumed by people from all walks of life due to its high nutritional quality, delicious taste, low cost, and importance as an animal protein source in human growth and development (3–5). Continuous genetic selection has produced fast-growing broilers with a short production cycle that reach market weight at 6 weeks of age and have a high meat yield, accounting for 74.81% (1, 5–7). The selection has had a negative impact on meat quality by increasing fiber diameters and the ratio of glycolytic fibers (8). Meat quality is a multifaceted character that is influenced by breed, strain, age, genetic, environmental, sex, and nutritional factors (2, 9, 10). Several studies have been conducted to assess the impact of nutrient supplementation on meat quality in chickens (11–14).

Antimicrobial growth promoters (AGPs) have been used in the poultry production industry for decades, resulting in a high risk of antibiotic-resistant bacteria being transferred to humans. It is difficult to raise broiler chickens in an antibiotic-free production system, and finding an effective nutritional alternative to support growth performance, gut health, and functionality without using AGPs is critical (15). Several non-antibiotic growth promoters are commercially available to improve bird growth, control pathogens, and reduce the risks of antibiotic resistance and misuse (16, 17). Examples include herbal essential oils, extracts, nano-emulsions and secondary metabolites (18, 19). Additionally, exogenous enzymes (20), organic acids (21), probiotics (15, 22), prebiotics (23), amino acids (24, 25), and green nanoparticles (26).

Essential oils (EOs), a type of phytogenic, are viable substitutes for increasing meat broiler production efficiency (27). EOs can be used therapeutically in a variety of broiler production situations due to their antibacterial, antiviral, antifungal, and antiparasitic properties (18). A combination of canola oil nano-emulsion and 2% Satureja bachtiarica essential oil is an effective natural preservative for chilled chicken breast (28). Rabbits, monogastric, fed a diet containing nano-emulsified essential oil had a higher final live weight, a higher carcass weight, a higher meat protein content, a lower fat content, and higher monounsaturated and polyunsaturated acids (29). Probiotics in animal feed is projected to attain massive global growth, reaching USD 6.24 billion by 2026 (15). High dietary energy content increases carcass weight (CW), carcass yield, and abdominal fat (30). The quality of chicken meat is becoming a significant issue when viewed from the perspectives of consumers and industries (31). The criteria for meat quality include pH, color, water holding capacity, cook loss, myofibril fragmentation index, and shear force (2). Texture profile analysis is a constructive technique that uses a popular double compression test to mimic the bite action of the mouth to determine the textural properties of poultry meat (32).

There are very few studies in the literature that look at the effects of sex and water supplementation of nano-emulsified plant-oil on meat attributes viz processing characteristics, physicochemical properties, and meat quality traits of broiler chicken. On the other hand, the addition of nanoparticles such as zinc nanoparticles and curcumin nanoparticles to broiler feed and Bacillus licheniformis improved the weight, carcass characteristics, and meat quality of chickens (18). Thus, the objective of this study was to determine the effects of water supplements of Magic oil plus probiotics and sex on processing characteristics, physicochemical properties, and meat quality traits of broiler chickens.

This study was approved by the Ethics Committee of Scientific Research, King Saud University (KSU), Saudi Arabia (Approval No: KSU-SE-21-02).

The results of the physicochemical properties are shown in Tables 2–4. The results of the main effects: treatments and sex of broilers, and their interactions on the initial and ultimate color components (lightness, redness, and yellowness) and their derivatives of breast meat at 35 days of age are summarized in Tables 2, 3, respectively. While the results of the main effects; treatments and sex and their interactions on the initial and final values of pH and temperature of breast meat at 35 days of age are shown in Table 4. The results of meat quality characteristics of both male and female broiler chickens supplemented with Magic oil and probiotic are shown in Table 5. The data in Table 6 show the main effects of treatments and sex on carcass measurements at 35 days of age, as well as the effects of interaction between treatments and sex of broilers. The effects of treatments, sex, and their interaction on processing performance (weight of chilled carcass, yield of cooked carcass, breast, legs, wings, back, and neck in percent) at 35 days of age are shown in Table 7.

The efficacy of Magic oil, a natural nano-emulsified plant-oil, was compared to probiotic on carcass traits and breast quality in broiler chickens in this study. Nano emulsions are used in the food industry to encapsulate, protect, deliver, and transport hydrophobic (low water solubility) bioactive components such as nutrients, nutraceuticals, antimicrobials, and antioxidants (40, 41). They are composed of tiny oil droplets suspended in water and act as a vehicle for essential oils to be bioavailable (18). Recent studies on the quality of meat or carcass traits of birds supplemented with powder, essential oils, or extracts of phytogenic in diets have been conducted (42–46). Unfortunately, little or no research has been conducted to examine the effect of water supplementation of Magic oil as nano-emulsified plant-oil and probiotic on the meat attributes of birds. At a probability level of α ≤ 0.05, the null hypothesis states that the effects of Magic oil and probiotic, sex, and their interactions on processing characteristics, physicochemical properties, and meat quality traits of broiler chickens are equal to the effects of the control group. Treatments, sex, and their interactions, according to the alternative hypothesis, improved some or all of the selected parameters.

Meat color is influenced by many factors, such as pre-slaughter factors, heme pigments, stunning methods, moisture content, cooling regimes, sex, strain, stress, and protein physical status (47). In agreement with Yetişir et al. (48), who noted that a higher L^* value would be preferable in terms of consumer acceptance. In our study, male birds had significantly higher initial L^* and whiteness index values (47.11 and 46.72, respectively) than females (44.91 and 44.49, respectively). Identifying color is an easy way to determine the pH of meat. If the meat is very dark, the pH is high, and if it is very light, the pH is low. Female birds in the control group, for example, were very light (Li^* = 48.29) and had a low pH (initial pH = 6.06). Birds given Magic oil between the ages of 0 and 30 days had a numerically higher initial Li^* = 46.18, resulting in a numerically higher initial WI = 45.82. Treatments, sex, or their interactions had no effect on the other color components and derivatives in breast meat. According to Abudabos et al. (49), no treatment effect of nano-emulsified plant oil or betaine was observed in L^*, a^*, b^*, color saturation, hue angle (H°), and a^* to b^* ratio.

The pH is defined as the negative log of the concentration of hydrogen ions and the pH parameter was a good predictor of meat characters (9). After slaughter, oxygen deprivation raises hydrogen ion concentrations due to lactic acid dissociation via the anaerobic glycolysis pathway, resulting in a pH drop. The pH declines directly affect the protein solubility, protein denaturation, protein's capacity bind water, and shelf life (50–52). Thus, broiler breast meat with a high pH has a higher water-binding capacity than meat with a lower pH. Lower pH in bird meat groups with essential oil or phytogenic nano-emulsions essential oil may be responsible for inhibiting the integration of the deterioration of microorganism growth (53, 54). High pH (over 6.2) and low pH values (below 5.8) can negatively influence meat quality of broiler breast meat [dark, firm, and dry (DFD) vs. pale, soft, exudative (PSE), respectively] (46, 50, 55). As a result, our data fell within the normal meat quality pH values (5.9–6.2), with initial pH ranging from 6.03 to 6.21 and final pH ranging from 5.87 to 5.99. Protein denaturation, a protein's ability to bind water, tenderness, and springiness were not impacted by treatment because the concentration of hydrogen ions in the muscle of broiler breasts was unaffected by treatment. This contradicts Abudabos et al. (49), who stated that diet only affected breast filets pH at 24 h post-mortem; the control had lower breast pH than betaine, while nano-emulsified plant oil had an intermediate temperature.

The term “water holding capacity” describes a muscle's capacity to bind water under specific circumstances. Usually, a sharp pH drop in meat can denaturize proteins, leaving behind pale meat with low WHC. According to Hughes et al. (56), decreasing water retention is linked to a decrease in the nutritional value of the meat due to the loss of some nutrients, which makes the breast meat less tender. It also tends to result in less reflective surface light, which lowers L^* values. Cooking loss is the proportion of water lost during cooking due to shrinkage, which is related to the loss of juiciness to the palate. Usually, an increase in WHC accompanied by a decrease in the percentage CL (57, 58). Although cooking loss was significantly lower when broilers were supplemented with Magic oil from 0 to 30 days of age in both males and females, WHC in this study did not show any significant differences in treated groups compared with control.

Myofibrillar fragmentation is the extent of myofibrillar destruction caused by homogenization. The treatments had no effect on the MFI of the breast muscle. Myofibrillar fragmentation index values, according to Olson and Stromer (59), are strongly correlated with other muscle measurements such as tenderness. Magic oil supplementation, on the other hand, did not differ from the control in terms of myofibril fragmentation. The SF of the birds' breast muscle, on the other hand, ranged from 5.5 to 5.8 kgf/g (60) and from 2.71 to 3.31 kgf/g (61). As the SF values in this trial ranged between 5.15 and 5.77 N, the Magic oil or probiotic supplementation groups had no effect on meat tenderness. These findings are consistent with those of Pokoo-Aikins et al. (46), who found that different levels of dietary DL-Methionine supplementation had no effect on the meat toughness value of broilers. The dietary methionine level, the sex of the bird, and their interactions had no effect on the textural properties of cooked meat (46). According to Hussein et al. (10), females had more tender pectoral muscles and more myofibrillar fragmentation than males.

The texture profiles (cohesiveness and chewiness) of the treatments differed significantly, with the Magic oil groups having lower levels of cohesiveness and chewiness than the probiotic group. In general, the effect of treatment and sex interaction on meat tenderness resulted in variation between sexes rather than between treatment groups; thus, female meat was tenderer than male meat in each treatment group except in the group supplemented with Magic oil from 0 to 30 days of age, where male meat was tenderer than female. Furthermore, male meat in the control group was the highest SF value compared to other groups. Thus, meat quality could be enhanced by adding natural antioxidant compounds, and Magic oil has the highest antioxidant capacity due to its high phenolic content. Foods fortified with micro/nano encapsulated vegetable-essential oils can improve their functional properties such as antioxidant and antimicrobial activity, as well as having more healthy unsaturated fatty acids (62).

The current study found that Magic oil additives improve meat quality, especially when supplemented from 0 to 30 days of age, with favorable chewiness in female broiler chickens (2.38) that resulted in lower cohesiveness (0.39) and hardness (7.38) and higher springiness (86). Female cage-reared broilers had higher meat quality in the breast muscle (63). Due to chewiness equal cohesiveness^*hardness^*springiness, which indicated chewiness was influenced by one or more of these parameters and has a direct relationship. In addition, the group that supplemented with Magic oil from 0 to 30 days of age were the most convenient cooking loss value and holding water.

Female broiler chickens in the supplemented probiotic group from 0 to 4 and 16 to 18 days of age had a rapid drop in meat pH (0.24) within 24 h postmortem compared to the other group, resulting in low WHC (29.62). Furthermore, the probiotic group had the highest cohesiveness (0.45), greater hardness (10.72), and the lowest springiness (0.77), which resulted in higher chewiness (3.95) and lower tenderness (5.54). These findings support the findings of Loddi et al. (64) who noticed that probiotics added to water and feed had no effect on the sensory characteristics of meat. On the other hand, Jensen and Jensen (65) found a positive impact of probiotics including Bacillus licheniformis and Bacillus subtilis spores on the flavor of broiler meat after cooling for 5 days. Several studies have suggested that nanoemulsion-based products can positively influence the physicochemical and sensory properties of breast muscles (66). Conversely, some authors have observed that natural antioxidants have little or no effect on the sensory characteristics of meat. For example, dietary supplementation with nano-emulsified vegetable-essential oils (49) or probiotic (16) had no effect on the quality of chicken meat in terms of myofibril fragmentation index, cooking loss, shear force, and texture profile analysis.

In the current study, male birds had 18.06% more live weight, 18.61% more hot carcass weight, and 17.04% more chilled carcass weight, resulting in 0.55% more carcass yield than female birds at marketing age. Female birds, on the other hand, weighed 6.67% more relative gizzards, 14.29% more relative neck weight, and 3.08% more relative wings than males. These results agree with those reported by others (10, 30, 67). The percentages of carcass yield, abdominal fat, liver, and heart were not significantly different between males and females. These findings partially contradict Majid et al. (68), who found a significant difference between males and females in most carcass cut weights.

In this experiment, the same level of Magic oil was used at different stages of bird development: from day one to slaughter, from 1 to 4 days, then 17 to 21 days and 25 days, and from 1 to 4 days, then 7 days to slaughter. However, the obtained results in this study varied depending on the treatment period. As a result, more researches are prompted to investigate different levels of Magic oil at different growth periods of birds in order to determine the best level of supplementation. These findings are in contrast with Abudabos et al. (49) who stated that dietary supplements of nano-emulsified plant oil/betaine had no effect on dressing, leg, fat, gizzard, spleen, or thymus, but had a significant effect on breast meat, liver, and bursa and in contrast to Nisar et al. (16), who claimed that treatments had no effect on carcass characteristics.

In conclusion, both water supplements of Magic oil and probiotic had no negative effects on the color, pH, temperature, or processing performance of breast meat. Male broiler chickens supplemented with Magic oil from 0 to 30 days of age had the best options in terms of chewiness as they had lower cohesiveness and hardness besides higher springiness, as well as the most convenient cooking loss value and water holding capacity. The results showed that male birds had higher initial lightness, water holding capacity, shear force, live weight, hot and chilled carcass weights, as well as a lower gizzard and neck percentage than female. These findings could also be used as a foundation for future studies of water supplementation of nanoemulsified plant oil and probiotics and their effects on performance, carcass quality and meat traits of broiler chickens.

The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation.

The animal study was reviewed and approved by the Ethics Committee of Scientific Research, King Saud University (KSU), Saudi Arabia (Approval No. KSU-SE-21-02).

GS and EH: conceptualization. AA, GS, and EH: methodology and investigation. HA-B: software. RA, GS, and EH: validation. RA: formal analysis. AA-O: resources and funding acquisition. HB-A: data curation. MQ, GS, and EH: writing—original draft preparation. AS: writing—review and editing and supervision. GS: visualization. GS and AA-O: project administration. All authors have read and agreed to the published version of the manuscript. All authors contributed to the article and approved the submitted version.