Ethiopian chickens are raised in diverse management and production systems, ranging from family-based poultry farming to medium and large-scale intensive systems (FAO, 2020). The quality of chicken meat is becoming an increasingly important concern for both consumers and the poultry industry (Zhuang and Savage, 2013). Study demonstrated that chicken meat is in highly demand due to its high protein content, low fat and cholesterol levels, and affordability implication (Mazzoni et al., 2015). Similarly, chicken meat consumption is free from cultural or religious restrictions (Smith et al., 2012). Numerous studies have shown that factors such as breed, strain, age, sex, and diet can affect meat quality (Petracci et al., 2013). Meat quality is determined by factors such as color, pH, water-holding capacity, drip loss, cooking loss, and shear force (Wilkins et al., 2000; Katemala et al., 2022).

Studies indicate that chicken meat color is a key quality indicator and strongly influences consumer buying preferences (Castellini et al., 2008; Hailemariam et al., 2022). Meat color is mainly determined by myoglobin, while hemoglobin and cytochrome C also contribute (Fanatico et al., 2007; Hailemariam et al., 2022). According to some studies, the CIE L*a*b* and Munsell C*h* systems can be used to measure the color of meat (Russel et al., 2014; Lee et al., 2022), as well as utilizing human senses (Liu et al., 2004). Studies have noted that meat pH is mainly influenced by the amount of glycogen present in the muscle at slaughter (Comert et al., 2016). Study has confirmed that meat pH levels at 45 minutes and 24 hours post-slaughter are critical indicators for assessing chicken meat quality (Baéza et al., 2022; Benjamin et al., 2024). 

According to previous findings, the normal pH values of meat are 6.01–6.70 at 45 minutes and 5.50–6.01 at 24 hours post-mortem, respectively (Jaturasitha et al., 2008). A pH below 5.70 measured 45 minutes postmortem suggests the meat is pale, soft, and exudative  (Biesek et al., 2022), while meat that has a pH value of more than 6.20 24 hours after death is considered dark, firm, and dry and affect the meat standard or grade levels (Chodova et al., 2021). Meat tenderness is considered one of the key qualities that influence consumers meat purchasing decisions (Cruz et al., 2018), and it can be measured using the Warner-Bratzler or Kramer shear force methods (Cavitt et al., 2004; CIE, 1976). The water-holding capacity of meat refers to its ability to retain its natural moisture or absorb added water when subjected to external forces (Russel et al., 2014). According to some reports, the water-holding capacity of meat plays a crucial role in both whole meat and processed meat products (Chuaynukool et al., 2007). The results indicated that a lower pH is linked to reduced water-holding capacity (WHC), leading to higher cooking and drip loss (Gálvez et al., 2020; Hailemariam et al., 2022a).

The genetically enhanced Horro chicken breed in Ethiopia (H) has demonstrated improved performance in both growth and egg production (Wondmeneh, 2015). The imported Cosmopolitan chicken (C) is regarded as a symbol of worldwide chicken genetic diversity (Hailemariam et al., 2022b). The Koekoek (KK) dual-purpose chicken was also brought in from South Africa (Dawud et al., 2019). The indigenous chicken (L) served as a reference for selection and breeding  (Halima et al., 2009). Given that the Cosmopolitan genotype is newly introduced to Ethiopia, it is clear that initial research and documentation are needed before its broader dissemination, providing valuable insights for future studies. The Cosmopolitan (C) and Improved Horro (H) breeds were crossed in both direct and reciprocal ways: Cosmopolitan♂* Improved Horro♀ (CH) and Improved Horro♂* Cosmopolitan♀ (HC), with the hypothesis that there would be variations in drumstick meat quality characteristics among the experimental chickens. These drumstick meat traits were compared with those of the indigenous (L) and Koekoek (KK) genotypes.

General Objective

The general objective of the study was to compare the drumstick meat quality traits under controlled on-station conditions.

Specific Objectives

The specific objectives are indicated below as:

1. To compare the instrumental tenderness of drumstick meat of different chicken genotypes.
2. To compare the drip loss of drumstick meat of different chicken genotypes.
3. To compare the cooking loss of drumstick meat of different chicken genotypes.
4. To compare the waterholding capacity of drumstick meat of different chicken genotypes.
5. To compare the pH ofdrumstick meat of different chicken genotypes.

Description of the Study Areas

The experiment was collaborately carried out at the Werer Agricultural Research Centre (WARC) in Ethiopia, located 280 km from the capital, Addis Ababa and Bangladesh. The center sits at an altitude of 820 meters above sea level, with coordinates of 55′ N latitude and 40° 40′ E longitude. The annual rainfall at WARC ranges from 400 mm to 600 mm, and the average minimum and maximum temperatures are 19.3 °C and 45 °C, respectively.

Ethical Clearance, Experimental Animals, Managements, and Sampling Procedures

Ethical Clearance and Experimental Animals

This experiment was conducted in accordance with the guidelines approved by the Institutional Animal Care and Use Committee (IACUC) and was carried out in collaboration with the study reported in (Hailemariam et al., 2022). A total of 144 chickens, evenly distributed among the six genotypes, were selected for slaughter. The experimental genotypes consisted of: I = Improved Horro (H), II = Cosmopolitan (C), III = Koekoek (KK), IV = Indigenous (L), V = Cosmopolitan♂*Improved Horro♀ (CH), and VI = Improved Horro♂*Cosmopolitan♀ (HC).

Managements and Sampling Procedures

Before the experiment began, the watering and feeding troughs, as well as the laying nests, were cleaned, disinfected, and treated for external parasites. The floor of each pen was covered with disinfected grass hay, replaced as necessary. All hens, both indigenous and imported, were hatched on the same day and fed the same commercial starter, grower, and layer rations appropriate for their age phases (Alema Koudjis; Feed Co., Ltd., Debrezeit, Ethiopia). The hens were vaccinated against Newcastle disease, Gumboro (Infectious Bursal Disease-IBD), and Fowl Typhoid with the appropriate vaccines following the manufacturers recommendations (NVI-Ethiopia). The experimental chickens were kept under uniform on-station conditions throughout the study, with regular health monitoring. Feed from Alema Koudjis; Feed Co., Ltd., Debrezeit, Ethiopia, was used, and supplements such as vitamin-mineral premixes and amino acids were provided following the manufacturers guidelines. The pens were also furnished with laying nests to fulfill all necessary requirements.

Quality of Drumstick Meats of Different Chickens

Meat Color and PH

The meat color parameters (CIE L*, a*, and b* values) were determined using a HunterLab MiniScan EZ (MSEZ-4500L, Serial No. MsEZ1547) with a 45/0° illumination/viewing system, D65 light source, and 10° observer angle (Honikel, 2009). The L* value indicates lightness, a* measures the red-green range, and b* measures the blue-yellow range. A digital colorimeter (Hunter Lab MiniScan EZ, Washington, DC, USA) calibrated with black and white standardized plates was used, with three readings taken at different locations on each sample and averaged. Meat pH was measured using a portable pH meter (Meat pH meter-HI99163, HANAN Instruments) equipped with an InLaB Solids Pro puncture-type sharp blade electrode, following the manufacturers instructions. The probe was cleaned with distilled water and calibrated with pH 4.01, 7.01, and 10.01 standard buffer solutions between sample measurements. Meat pH was recorded at 45 minutes and 24 hours post-mortem, with three readings taken at different locations per sample and averaged. For color measurement, the internal face of the cranial position of the filleted drumstick meat samples was exposed on a flat white background in the measurement room for about 45 minutes at ambient temperature (24°C ± 1.2°C). This study included 144 genotypes, with 24 per genotype and 6 samples per cut. The six drumstick meat samples per cut were averaged to determine meat pH and color measurements for each genotype. Hue and Chroma were computed using these formulas: Hue (h)= Arctangent(b/a), Chroma (C)=(a2+b2)1/2

Water Holding Capacity (WHC%)

The water-holding capacity of the meat was measured 24 hours postmortem using the method outlined by Whiting and Jenkins (1981). Two Whatman number-1 filter papers were weighed, and a 0.5 g meat sample was placed between them, which was then positioned between two glass sheets. Over it, a weight of 2.015 kg weight was placed while the glass sheet weighed 0.8278 kg sheet, giving a total compression weight of 2.8428 kg load for 5 min. Then the weight was removed, and the meat was separated from the filter papers and weighed. In the end, the filter paper was dried and the weight was recorded. After that, the amount of protein attached to the filter paper and the actual weight of meat after pressure treatment was determined. The water holding capacity (WHC%) was calculated as: WHC(%) = (ASWBPT-ASWAPT/ ASWBPT)*100, where; ASWBPT = Actual Sample Weight Before Pressure Treatment, ASWAPT = Actual Sample Weight After Pressure Treatment.

In this study, a total of 144 chickens, with 24 per genotype and 6 samples per cut, were analyzed. The water-holding capacity (%) of each genotype was calculated by averaging the six-sample drumstick meat cuts.

Instrumental Tenderness Determination

Instrumental tenderness was measured using the Warner-Bratzler shear force (WBSF) method. The steaks were cooked to 70°C and allowed to cool to room temperature (24–25°C) for about an hour before testing. After cooling, the steaks were cut across the long axis, ensuring the knife tip was placed on the heavy connective tissue side and the handle on the ventral side to align with the fiber direction. Six cores (1.27 cm in diameter) were removed parallel to the muscle fibers. It was essential to ensure the fibers ran parallel to the core to achieve a shear across the grain. The WBSF device was used to shear each core, with the peak values recorded in Newtons (N). The average shear force for the six cores was taken as the final value for each steak. Meat samples were categorized as very tender (WBS <31.4 N), tender (31.4 N < WBS <38.3 N), intermediate (38.3 N < WBS <45.1 N), and tough (WBS >45.1 N) based on the WBSF values (Mueller et al., 2020). A total of 144 genotypes, with equal replicates for each chicken, were measured six times, and the average was used to determine the instrumental meat tenderness for each genotype in the study.

DripLoss (%)

Drip loss of the drumstick meat samples from the reared chickens was measured using the plastic drip method (Honikel, 2009). A 30 g meat sample was taken, cut perpendicular to the fiber direction at the widest part of the muscle. The samples were placed in an inflated plastic bag and stored in the refrigerator at 4°C for 24 hours, then reweighed. The six genotypes were measured with equal replication for the drumstick meat considered in the study. A total of 144 genotypes were used, with 12 drumstick cuts per genotype. The collected data were averaged to determine the drip loss percentage for each genotype. Drip loss (DL%) was calculated as: DL (%) = [(ISWT - FSWT) / ISWT] * 100, where ISWT = Initial Sample Weight and FSWT = Final Sample Weight.

CookingLoss (%)

The cooking loss of the drumstick meat samples from the experimental chickens was assessed using the plastic drip method (Honikel, 2009). A 30 g meat sample was taken, cut perpendicular to the muscle fibers at the widest part of the sampled muscle. The samples were placed in an inflated plastic bag, stored in the refrigerator at 4°C for 24 hours, and then reweighed. The study involved 144 genotypes, with 24 per genotype and 6 samples per cut. The cooking loss measurements for each genotype were determined by averaging the six sample cuts. Cooking loss (CL%) was calculated as: CL (%) = [(WRS - WCS) / WRS] * 100, where WRS = Weight of Raw Sample and WCS = Weight of Cooked Sample.

Statistical Analysis

The drumstick meat data was recorded on a prepared sheet and regularly entered into Excel. The collected data was subsequently summarized and analyzed using the GLM model in SAS software (SAS, 2004). When the GLM analysis showed a significant difference at P<0.05, Duncans multiple range test was used to separate the means.

The model used for the analysis: Yij=µ+Gi+eij

Where,

Yij = the response variables

µ = the overall Mean

Gi = the effect of genotype (I =1,2,3,4,5,6)

eij = Randomerror

Genotype Effect on Drumstick Meat Quality of Different Chickens

Effect on Instrumental Tenderness of Drumstick Meat of Different Chickens

The result of the effect of genotypes on Instrumental tenderness of drumstick meat (WBSF) of different chickens is indicated in Fig. 1. The shear force (WBSF) of the KK drumstick was significantly the highest (41.52 N), followed by higher values in CH (38.71 N) and C (38.49 N). The WBSF values were also elevated in HC (36.38 N) and H (35.79 N), while the L genotype had the lowest WBSF (33.65 N). These findings are consistent with the idea that variations in meat shear (WBSF) values are due to breed differences that affect tenderness as measured by instruments (Fanatico et al., 2007; AMSA, 2012; Clapano et al., 2022).

Fig. 1: Instrumental tenderness (WBSF) of drumstick meat of different chickens.

Waterhoding Capacity of Drumstick Meat of Different Chickens at 24 Hours

The result of waterhoding capacity of drumstick meat of different chickens at 24 hours is indicated in Fig. 2. The drumstick meats from the L (83.69) and H (82.26) genotypes had the highest water holding capacity (WHC) values, significantly higher than HC (80.09) and C (82.63), which also had high WHC values. The CH genotype showed a lower WHC (79.74), while the KK genotype had the lowest WHC value (77.36). Variations in WHC in chicken meat are linked to breed differences in water retention, which can be attributed to variations in composition and quality (Hailemariam et al., 2022a; Hailemariam et al., 2022b).

Fig. 2: Waterholding capacity (WHC) of drumstick meat of different chickens.

pH of Drumstick Meat of Different Chickens at 45 Minutes and 24 Hours

The result of pH of drumstick meat at 45 minites (min) and 24 hours (hr) is presented in Fig. 3. The CH drumstick had the lowest pH45 value (6.57), with slightly higher values in KK (6.59) and C (6.62), and a lower value in HC (6.64).

Fig. 3: pH of drumstick meat of different chickens at 45 minutes and 24 hours.

 In contrast, the H genotype had a higher pH45 value (6.65), while the L drumstick meat exhibited the highest pH45 value (6.68), which was significantly greater. The L drumstick also showed a significantly higher pH24 value (5.95) compared to H (5.92) and HC (5.91). Conversely, the lowest pH24 values were observed in the drumstick meat from C (5.89), CH (5.88), and KK (5.88) genotypes. The variation in meat pH is related to the degree of acidification in the meat (Muth and Zarate, 2017). These findings suggest that differences in pH are due to the glycogen levels stored in the muscle at the time of slaughter (Kokoszyński et al., 2020).

Fig. 4: Cooking loss (CL) of drumstick meat of different chicken.

Cooking Loss (Cl) of Drumstick Meat of Different Chicken

The result of cooking loss (CL) of drumstick meat of different chicken is presented in Fig. 4. Cooking loss (CL) was notably greater in the KK (25.51), CH (24.82), and C (24.64) genotypes than in HC (22.50), H (22.56), and L (22.34). These differences in CL across chicken breeds are linked to variations in glycogen breakdown (Fletcher, 2002; Wideman et al., 2016).

Drip Loss of Drumstick Meat of Different Chicken Genotypes

Fig. 5 shows the drumstick meat drip loss (DL) of different chicken genotypes. Drumstick meat from the KK (2.43) and CH (2.37) genotypes showed the highest drip loss, with C (2.31) and HC (2.29) also having elevated values. The H genotype had a lower drip loss (2.21), while the L genotype recorded the lowest and significantly reduced level (2.16). These differences in drip loss among genotypes are linked to variations in connective tissue structure and arrangement (Wattanachant, 2008).

Drumstick Meat Color Traits of Different Chickens

The result of drumstick meat color traits of different  chickens is presented in Table 1. 

Fig. 5: Drip loss (DL) of drumstick meat of  different chicken genotypes.

Drumstick meat from the KK (56.42±0.44), CH (55.81±0.41), and C (55.54±0.43) genotypes displayed significantly higher lightness (L*) values compared to HC (51.35±0.40) and H (51.09±0.38), while the L genotype had the lowest lightness value (50.39±0.37). Previous studies suggest that genotype plays a role in influencing meat lightness. Regarding redness (a*), HC (5.48±0.18), CH (5.55±0.19), and KK (5.61±0.17) showed lower scores than C (6.40±0.23), H (6.29±0.25), and L (6.26±0.29), reflecting genetic differences in meat color (Debut et al., 2003; Mueller et al., 2020). 

Table 1: Effect of Genotype on Drumstick Meat Color Traits.

Mean under the same category bear different superscript letters are significantly different, ***  = P < 0.001, *** = P < 0.01  SE = Standard error

Yellowness (b*) was significantly greater in KK (15.75±1.29), CH (14.99±1.69), and C (14.78±1.26), compared to HC (11.28±1.34), H (10.90±0.85), and L (10.65±0.89), consistent with reports linking b* values to genetic variation (Russel et al., 2014). Similarly, chroma (C*) values were higher in KK (16.71±0.39), C (16.11±0.37), and CH (15.98±0.27) than in HC (12.54±0.36), H (12.58±0.15), and L (12.35±0.19), with prior studies noting elevated C* scores in Naked-Neck and Hybrid breeds (Russel et al., 2014; Wondmeneh, 2015). The hue angle (h*) was also significantly higher in KK (70.41±1.19), CH (69.68±1.16), and C (66.59±0.73) compared to HC (64.28±0.92), H (59.97±0.75), and L (59.53±0.68), in line with findings that hybrids and Koekoek chickens often have higher hue values than broilers (Wideman et al., 2016). Overall, variations in meat color are attributed to differences in muscle biochemistry, such as myoglobin concentration, cytochrome C content, heme structure, pH levels, and fiber type distribution (Sarsenbek et al., 2013; Wattanachant, 2008).

The KK genotype exhibited the highest shear force (WBSF), followed by C and CH, while the L genotype had the lowest WBSF. Drumstick meat from L and HC genotypes showed the greatest water-holding capacity (WHC), with C and HC also displaying elevated WHC values; in contrast, KK had the lowest WHC. The pH45 was lowest in KK, slightly higher in C and HC, higher in H, and significantly highest in L. For pH24, the L genotype had the highest value, while H and HC were intermediate, and C, CH, and KK recorded the lowest values. Cooking loss (CL) was more pronounced in KK, CH, and C compared to H, HC, and L. Drip loss (DL) was highest in the KK and CH genotypes, followed by C and HC, while the L genotype showed the lowest DL. Lightness (L*) values were significantly greater in KK, CH, and C than in HC and H, with L having the lowest score. Redness (a*) was reduced in KK, CH, and HC compared to H and C, whereas yellowness (b*) was higher in KK, CH, and C than in HC, H, and L. Similarly, chroma (C*) and hue angle (h*) values were elevated in KK, CH, and C relative to HC, H, and L. In conclusion, these findings underscore the substantial influence of genetic variations on drumstick meat quality attributes of different chicken genotypes. This study might also be recommendable to serve as a reference for future research into the quality characteristics of drumstick meat across diverse chicken genotypes, aiding in the selection and breeding of poultry for improved meat quality.

A.H.G.: was responsible for conceptualizing the study, designing the methodology, formal analysis, and preparing the draft of the manuscript. M.R.R.; A.H.; M.R; and C.E.M.: contributed to data collection, collaborated in reviewing, financial assistance and editing the manuscript. All authors read and approved the final version.

Data Availability

Data will be made available on request.

The authors express gratitude to the International Livestock Research Institute (ILRI-ACGG) and the Ethiopian Institute of Agricultural Research (EIAR) for providing necessary opportunities. We also thank to the University authority as well as those who directly or indirectly contributed to the accomplish-ment of this study.

The authors declare no conflicts of interest.