*3.1. Biochemical Measurements*

At the beginning of the trial, the mortality rate was 2.5% (starter phase), while at the end of the experiment no mortality was recorded (0%). Table 2 revealed the biochemical measurements performed on serum samples. Serum glucose was significantly lower (by 19.72%) in E2 group compared to E1 and insignificant (*p* > 0.05) compared to the other groups (C, E3). Diets did not affect (*p* > 0.05) the other parameters such as cholesterol, triglyceride, phosphorus, calcium, iron, AST, ALT, gamma GT.


**Table 2.** Biochemical parameters determined in blood serum samples.

a,b Means within a column with no common superscript differ (*p* < 0.05). C: control diet; E1: experimental diet supplemented with 200 μg/kg diet CrPic + 0.25 g vitamin C (VC)/kg diet; E2: experimental diet supplemented with 200 μg/kg diet CrPic + 0.025 g Zn/kg diet; E3: experimental diet supplemented with 200 μg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet; ALT—Alanine aminotransferase; AST—Aspartate aminotransferase.

#### *3.2. Proximate Composition and Physicochemical Properties of Chicken Meat*

Data on proximate composition of breast and thigh samples collected at the end of the experiment are presented in Table 3.


**Table 3.** Proximate composition of thigh and breast meat samples.

a,b Means within a column with no common superscript differ (*p* < 0.05). Where: C: control diet; E1: experimental diet supplemented with 200 μg/kg diet CrPic + 0.25 g vitamin C (VC)/kg diet; E2: experimental diet supplemented with 200 μg/kg diet CrPic + 0.025 g Zn/kg diet; E3: experimental diet supplemented with 200 μg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet; DM = dry matter; CP = crude protein; EE—ether extractives; Ash.

In thigh meat, the concentrations of DM, CP and Ash did not differ (*p* > 0.05) between control group and experimental groups (E1, E2 and E3). However, the concentration of EE recorded significant differences (*p* < 0.05), being higher in E2 (CrPic + Zn) compared to C group.

In the analyzed chicken breast meat, there were significant increases (*p* < 0.05) in terms of CP and Ash and decreases in the EE. Thus, the dietary supplementation with CrPic + CWS determined the increase in crude protein concentration in breast meat compared to the C group; otherwise, the other groups had a statistically similar protein with group C. Additionally interesting is that CrPic + VC and CrPic + CWS caused a significant reduction in the concentration of crude fat in chicken breast compared to group C. The breast from E2 group had a significantly higher concentration of crude fat than E1 and E3, but similar to group C. Ash concentration was higher (*p* < 0.05) in groups E1 and E3

than in C. The group E2 had a significantly lower Ash content than in E1 and E3, but at a comparable level to C.

#### *3.3. Color Parameters of Chicken Samples (Thigh and Breast Meat)*

Table 4 shows the effects of diets on the color of thigh and breast muscle (pectoralis major). Supplementation of chicken diets with CrPic + VC (E1), CrPic + Zn (E2) and CrPic + CWS (E3) did not influence the value of the L\* parameter of thigh meat. In contrast, the value of a\* was significantly lower in the thigh collected from E1 than from E3 group. Yellowness parameter (b\*) was also lower in the thigh samples from C group than in those from E1 group, while no difference was recorded in the E2 and E3 groups.


**Table 4.** Color parameters of the chicken meat.

a–c Means within a column with no common superscript differ (*p* < 0.05). C: control diet; E1: experimental diet supplemented with 200 μg/kg diet CrPic + 0.25 g vitamin C (VC)/kg diet; E2: experimental diet supplemented with 200 μg/kg diet CrPic + 0.025 g Zn/kg diet; E3: experimental diet supplemented with 200 μg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet; L\*: luminosity parameter; a\*: redness; b\*: yellowness.

Regarding the chicken breast, the L\* parameter was significantly lower in the groups that included CrPic + VC, Cr + Zn, Cr + CWS in the diet than in the C group. Moreover, the values of a\* parameter were higher in E1, E2 and E3 groups compared with the C group. The breast of chickens fed E1, E3 diets had a significant lower yellowness (b\*) (*p* < 0.05) than those fed C diet. Notably is that the lowest value of b\* parameter was recorded in the breast samples collected from E3 diet.

#### *3.4. Meat Texture Parameters Determined by Shear with a Single Cycle and Double Cycle Compression*

The chicken thigh meat recorded significant differences in the shear force parameter (*p* < 0.05) between experimental groups (E1, E2, and E3) and C group (Table 5). The thigh meat collected from E1 was firmer compared to those collected from E2 and E3. The combined effect of chromium and vitamin C led to an increase in the firmness of the meat, the cutting force registering the lowest value (30.88 N). The thigh meat of chicken from group E3 was firmer compared to meat from group E2, but the differences were not statistically significant.

The analysis of the texture profile (TPA) of thigh samples resulting from the application of the double compression test shows that the parameters of hardness, elasticity, cohesiveness, and gumminess did not register significant (*p* > 0.05) differences between groups. Cohesiveness shows how well the sample retains its structure after compression and includes adhesive and cohesive forces as well as viscosity and elasticity. Gumminess, a secondary parameter in the analysis of the texture profile, is determined as a product between firmness and cohesiveness. The resilience of chicken thigh was significantly lower in the group that included CrPic + Zn (E2), CrPic + CWS (E3) in the diet compared to group C and E1. The lowest resilience value was obtained in group E2 (diet supplemented with CrPic + Zn). The pH values were lower (*p* < 0.05) in E2 and E3 compared to C group. The dietary inclusion of CrPic+ VC did not have a significant effect on the pH of the thigh meat.


**Table 5.** Texture parameters of thigh meat.

a–c Means within a column with no common superscript differ (*p* < 0.05). C: control diet; E1: experimental diet supplemented with 200 μg/kg diet CrPic + 0.25 g vitamin C (VC)/kg diet; E2: experimental diet supplemented with 200 μg/kg diet CrPic + 0.025 g Zn/kg diet; E3: experimental diet supplemented with 200 μg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet.

> The shear force showed inconsistent patterns concerning the supplemented diets (Table 6). It is observed that the breast meat obtained from groups E2 and E3 was characterized by a lower hardness (*p* < 0.05) compared to that from groups C and E1. The springiness of chicken breast collected from E2 and E3 groups did not differ significantly (*p* > 0.05) from that obtained for group C. Statistically significant differences were obtained between C and E1, the breast meat in group E1 showing a significantly lower elasticity (99.42%) compared to that of group C (99.74%). The resilience of chicken breast meat in groups E2 and E3 differs significantly (*p* < 0.05) from the values obtained in group E1. There were no differences between group C and the other groups. However, the lowest resilience value of breast meat (2.16 adm) was recorded in E2 group, which included CrPic + Zn in the diet. The cohesiveness and gumminess attributes of the chicken breast did not differ between groups. The inclusion of CrPic + VC in the chicken diet led to an increase in the pH of breast meat compared to C group. There were no significant differences in pH between C and E2 and E3. Diet supplementation with CrPic + Zn, and CrPic+ CWS respectively led to a significant decrease in pH value, compared to that of samples from E1.


**Table 6.** Texture parameters of breast meat.

a,b Means within a column with no common superscript differ (*p* < 0.05). C: control diet; E1: experimental diet supplemented with 200 μg/kg diet CrPic + 0.25 g vitamin C (VC)/kg diet; E2: experimental diet supplemented with 200 μg/kg diet CrPic + 0.025 g Zn/kg diet; E3: experimental diet supplemented with 200 μg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet.

> *3.5. Relationship between Meat Characteristics*

Figure 1 shows the PCA plot for chemical characteristics, L\*, a\*, b\* color parameters, textural parameters, and some sensorial characteristics.

**Figure 1.** Principal component loading based on the chemical composition, L\*, a\*, b\* color parameters, textural parameters, and sensory characteristics. L\*: luminosity parameter; a\*: redness; b\*: yellowness; DM: dry matter; CP: crude protein; EE: ether extractives.

The first two PCs explain 50.81% of the total variance (PC1 = 32.30%, PC2 = 18.51%) for the evaluated characteristics. Some sensory characteristics such as muscle fiber appearance, appearance and fat characteristics, and smell were eliminated from the PCA because they have a low adequacy for PCs. The first principal component, PC1 was associated with chemical composition (CP, EE, and Ash) and L\*, a\*, b\* color parameters. The second component, PC 2 was characterized by dry matter (DM), textural parameters (hardness and gumminess), and sensory characteristics (consistency, juiciness, and tenderness). Meat tenderness shows a weak negative correlation with EE (r = −0.342), which may be related to the intramuscular fat content that affects tenderness. Significant (*p* < 0.01) positive correlation was found between hardness and gumminess (r = 0.891), gumminess and cohesiveness (r = 0.771), between cohesiveness and resilience (r = 0.861), and EE (r = 0.585). A positive correlation was also found between Ash and L\* (r = 0.426), and a negative one between Ash and a\* (r = 0.446).

As Figures 2 and 3 show, the panelists indicated similar sensory attributes for chicken breast and thigh among groups. Thus, the dietary supplementation had not changed the consumer acceptance criteria.

**Figure 2.** Sensory characteristics of chicken's breast (mean of points). Main effects of diets are presented in each graph (Prism Graph 9.02). Data are presented as mean ±SEM (n = 6 samples/group).No superscript denotes any statistical significance (*p* > 0.1234). C: control diet; E1: experimental diet supplemented with 200 μg/kg diet CrPic + 0.25 g vitamin C (VC)/kg diet; E2: experimental diet supplemented with 200 μg/kg diet CrPic + 0.025 g Zn/kg diet; E3: experimental diet supplemented with 200 μg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet.

**Figure 3.** Sensory characteristics of chicken's thigh (mean of points) Main effects of diets are presented in each graph (Prism Graph 9.02). Data are presented as mean ± SEM of points (n = 6 samples/group). No superscript denotes any statistical significance (*p* > 0.1234). C: control diet; E1: experimental diet supplemented with 200 μg/kg diet CrPic + 0.25 g vitamin C (VC)/kg diet; E2: experimental diet supplemented with 200 μg/kg diet CrPic + 0.025 g Zn/kg diet; E3: experimental diet supplemented with 200 μg/kg diet CrPic + 10 g creeping wood sorrel powder (CWS)/kg diet.
