Influences of end-point heating temperature on the quality attributes of chicken meat

1. This study aimed to evaluate the changes in physicochemical, textural and sensory characteristics of broiler (BR) and Taiwan native chicken (TNC) pectoralis muscle heated at temperatures of 50–95°C.

2. With increasing temperature, cooking loss, collagen solubility, shear force value and hardness, of samples increased in both chicken breeds. Rapid decreases in protein solubility were observed when the meat was heated to 50°C and gradually decreased thereafter.

3. Meat from BRs and native chickens performed differently upon heating in certain characteristics. TNC meat had longer cooking time and lower myofibrillar fragmentation index than BR meat did. TNC meat had higher collagen content, shear force values and springiness but lower collagen solubility than BR meat did.

4. BR meat had significantly higher onset and end transition temperatures than TNC meat did. In BR meat, a sensory analysis revealed that moisture release decreased and chicken flavour increased with increasing temperature.

5. Protein solubility, cooking loss and the texture of heated meat were highly correlated.

6. This study scientifically assessed the performances of the two breeds of chickens with different thermal treatments; producers could utilise the information to produce poultry products with more desirable qualities.

     

Growth performance,carcass traits and meat quality of yellow‐feathered broilers fed graded levels of alfalfa meal with or without wheat

The effects of 0, 40 and 80 g/kg alfalfa meal on growth performance, carcass traits and meat quality of Chinese yellow‐feathered broilers fed diets containing or lacking wheat (0 or 200 g/kg) as part of the energy source, were examined using random design with a 2 × 3 factorial arrangement of treatments. Dressing percentage and semi‐eviscerated proportion were lower, and meat color a* (redness) value was higher in birds fed diets containing wheat than diets lacking wheat (P < 0.05). Drip loss was reduced by the addition of alfalfa meal to diets containing or lacking wheat (P < 0.05). Average sensory score of breast meat was higher in chickens fed corn‐based diets than in those fed wheat (P < 0.05). Meat from those supplemented with 40 g/kg alfalfa meal had better taste than the other two levels (P < 0.05). The inclusion of wheat significantly reduced the activities of creatine kinase and calpain of breast muscle (P < 0.05). In conclusion, Chinese yellow‐feathered broilers fed diets containing wheat had better meat color and lower drip loss than those fed the diets without wheat, and adding 40 g/kg alfalfa meal generally improved meat quality and taste.     

Influence of stewing time on the texture,ultrastructure and in vitro digestibility of meat from the yellow‐feathered chicken breed

This study assessed the influence of stewing (1, 2 or 3 h) on the texture, ultrastructure and in vitro digestibility of meat from the yellow‐feathered chicken, which is a popular broiler chicken in Asia. Results indicated that longer stewing considerably increased cooking loss of the chicken carcass and tenderness of thigh meat. After 3 h of stewing, protein digestibility decreased from 90.5% to 80.3% and fiber diameter decreased by 8.63 μm. The shear force value of breast meat decreased from 32.34 N at 1 h to 10.29 N at 2 h, and then increased to 39.98 N at 3 h. The texture profile of breast meat remarkably decreased during stewing. Moreover, increased stewing time induced longitudinal and transversal shrinkage of muscle fibers and the degradation of the myosin heavy chain. These findings suggested that prolonged stewing (3 h) resulted in decreased meat qualities, based on the changes in cooking loss, digestibility and texture profile, but that stewing for 2 h increased thigh and breast tenderness. Producers could utilize this information to stew yellow‐feathered chicken meat with desirable qualities.     

Effect of dietary astaxanthin rich yeast,Phaffia rhodozyma,on meat quality of broiler chickens

We evaluated effects of dietary supplementation with astaxanthin (Ax)‐rich yeast, Phaffia rhodozyma (Xanthophyllomyces dendrorhous), on broiler chicken meat quality. Fourteen‐day‐old female Ross broilers were divided into three groups: control group, Ax‐free diet; Ax 10 group, 10 mg/kg Ax diet; and Ax 20 group, 20 mg/kg Ax diet for 28 days. At 42 days old, chickens were slaughtered, and then growth performance, meat quality and sensory attributes were analyzed. Compared with the control, a* values increased significantly after slaughter and 48 h postmortem for Ax 20 samples (P < 0.05) and for b* values in Ax 20 and Ax 10 groups (P < 0.05). Cooking loss decreased in the Ax 20 group (P < 0.05). After 120 h aging, contents of several free amino acids and total free amino acid content of Ax 20 group were significantly higher than the control (P < 0.05). In sensory evaluation, meat texture attributes improved significantly in the Ax 20 group (P < 0.01). No significant changes occurred in flavor attribute scores of meat soup from the Ax 20 group compared with the control even though most assessors preferred meat soup from the Ax 20 group. Overall, Ax‐rich yeast in the diet improves broiler chicken meat quality.     

The effect of sex on the quality of meat from farmed pheasants (Phasianus colchicus)

The present study aimed to investigate the influence of sex on the quality of meat from farmed pheasants. Male (roosters, n = 18) and female (hens, n = 18) pheasants were slaughtered at 25 weeks of age. The breast muscles (Pectoralis major) were cut out from chilled carcasses and analyzed to determine the proximate chemical composition, fatty acid profile, and physicochemical and sensory properties of meat. Chemical analyses revealed that the meat of male had higher (p ≤ .05) content of collagen, Na, Cu, and Zn, whereas meat from females had higher (p ≤ .05) concentrations of total nitrogen of water‐soluble compounds, nitrogen of water‐soluble non‐protein compounds, K, and Mn. The meat of male was characterized by greater (p ≤ .05) cooking loss. A sensory evaluation revealed that meat from females had lower (p ≤ .05) taste intensity and aroma desirability. Meat from male and female pheasants revealed differences in the content of minerals as well as low‐molecular‐weight water‐soluble nitrogen compounds, which may affect the flavor of cooked meat. Irrespective of these differences, the analyzed pheasant meat was characterized by high quality, which indicates that it could offer an attractive alternative to other types of meat.     

Increased collagen III in culled chicken meat after feeding dietary wood charcoal and vinegar contributes to palatability and tenderness

We comprehensively evaluated meat quality in chickens fed a diet consisting of wood charcoal and vinegar (WCV) using food scientific and histological approaches. In culled hens, lipid and fatty acid in Musculus semimembranosus, cooking loss and sensory tests of whole thigh meat, and meat texture of breast meat were observed. In male broilers, cross section of M. semimembranosus was used for observations on muscle area, perimysium, non‐collagen total protein and total collagen content, and anti‐collagen I and III reactions. In frozen male broilers, conventional morphology of M. semimembranosus as well as chicken anti‐collagen III reaction to selected muscles of thigh meat and breast meat were compared between the control and WCV‐fed birds. Increased lipid and fatty acids, decreased cooking loss, high score in total evaluation for sensory test of thigh meat, and decreased meat texture values were observed for culled hens fed WCV. The higher values of muscle area, total collagen and collagen III were observed for broilers fed WCV. No perimysium collapse for M. semitendinosus or increased collagen III reactions of M. tensor fasciae latae, the flexor muscle group and M. pectoralis superficialis were observed for frozen muscles in the WCV group. These total results suggest that WCV produces palatable and tender meat by increasing collagen III.     

Effects of different rearing systems on meat production traits and meat fiber microstructure of Beijing‐you chicken

Beijing‐you is a Chinese local chicken which is raised for both meat and eggs. In the present study, we detected the effects of different rearing systems on growth, slaughtering performances and meat quality of Beijing‐you chickens at 26–40 weeks of age. Six hundred Beijing‐you hens were randomly allocated into two groups at 16 weeks of age and raised in free range or battery cage systems. The body weight, slaughtering performance and meat quality were measured for each group at the ages of 26, 30, 35 and 40 weeks. Some of the traits were dramatically influenced by the two systems, although most of them did not show significant changes. For the meat fiber microstructure, we found that the diameter of thigh and breast muscle fiber in the free range group were significantly increased than in the cage group (P < 0.05) at 26 weeks of age. The ratio of fast muscle fiber in thigh muscle samples of the free range group was significantly reduced compared to that of cage group at both 35 (P < 0.01) and 40 (P < 0.01) weeks of age, indicating that the free range system could promote the transforming of fast muscle fiber to slow muscle fiber.     

Resveratrol beneficially affects meat quality of heat‐stressed broilers which is associated with changes in muscle antioxidant status

This study was conducted to evaluate the effect of dietary resveratrol (Res) supplementation on serum parameters, meat quality and muscle antioxidant status of broilers under heat stress (HS). A total of 270 21‐day‐old male Cobb broilers were randomly assigned to three treatment groups with six replicates of 15 birds each. The three treatment groups were as follows: the control group, in which birds were reared at 22 ± 1°C, and the HS and HS + Res (400 mg/kg) groups, in which birds were reared at 33 ± 1°C for 10 h (08.00–18.00 h) and 22 ± 1°C for the rest of the time. Compared with birds in the control group, birds in the HS group exhibited increased serum corticosterone (CORT) and triacylglycerol contents, L*, drip loss and muscle malondialdehyde content, and decreased serum glucose content, pH_24 h, muscle total antioxidant capacity (T‐AOC), catalase (CAT) and glutathione peroxidase (GSH‐PX) activities (P < 0.05). Compared with birds in the HS group, birds in HS + Res group exhibited increased serum glucose content, a*, pH_24 h, muscle T‐AOC and CAT activities, and decreased serum CORT and triacylglycerol contents, L*_24 h, drip loss and muscle malondialdehyde content (P < 0.05). In conclusion, Res beneficially protects against HS‐impaired meat quality of broilers through regulating muscle antioxidant status.     

Effect of muscle type and vacuum chiller ageing period on the chemical compositions,meat quality,sensory attributes and volatile compounds of Korean native cattle beef

The present study demonstrates the effects of different muscle types and chiller ageing periods on the chemical composition, meat quality parameters, sensory characteristics and volatile compounds of Karean native cattle beed. Longissimus dorsi (LD) and Semitendinosus (ST) muscles aged for 7 days and 28 days were used. Moisture, cooking loss, total collagen and Warner‐Bratzler shear force (WBSF) values for the ST were higher than the LD muscle regardless of ageing period (P < 0.05). The LD muscle had higher intramuscular fat (IMF) (P < 0.05). Ageing for 28 days decreased WBSF values whereas it increased thiobarbituric acid of both muscles. Moreover, tenderness, juiciness and flavor scores were significantly higher for the LD muscle at both ageing periods. Increased ageing time improved tenderness of both muscles, and increased juiciness of the LD muscle, whereas there was decreased flavor score of ST muscle (P < 0.05). The majority of the volatile compounds formed from the oxidation of lipids showed differences between the two muscles. Ageing for 28 days increased in the amounts of many volatile compounds; however, the amounts of some important volatile compounds were decreased. These results clearly demonstrate that muscle type and ageing have a potential effect on meat quality, sensory characteristics and volatile profile.     

Comparative studies on egg,meat, and semen qualities of native and improved chicken varieties developed for backyard poultry production

The objective of the present study was to evaluate/compare the sensory attributes of eggs and meat, egg qualities, proximate composition of eggs, and semen qualities of slow growing native (Miri and Mizo-local) and fast growing improved chicken varieties (Gramapriya and Vanaraja) under hill ecosystem of northeastern India. Significantly higher egg weight, egg volume, and albumen volume were observed in Gramapriya followed by Vanaraja, Mizo-local, and Miri chickens. However, yolk volume was significantly higher in Vanaraja and Gramapriya varieties as compared to native chickens. Yolk to albumen ratio was significantly lower in Gramapriya as compared to Vanaraja and Miri chicken. Consumer liking of eggs for aroma, flavor, and overall acceptability of Miri, Mizo-local, and Vanaraja were significantly higher than that of Gramapriya. Genetic groups did not differ significantly in appearance and proximate composition of eggs. No significant differences were observed between various genetic groups for sensory attributes of meat samples. Semen volume was significantly (p ≤ 0.01) lower while sperm concentration was significantly (p ≤ 0.01) higher in native chicken as compared to the improved chicken varieties. However, pH, mass activity, sperm motility, and livability did not differ significantly among genetic groups although Mizo-local had significantly higher abnormal sperm count. The study concluded that the genetic groups with different growth rate differed significantly for various egg quality parameters and semen characteristics but not for sensory attributes of meat and proximate composition of eggs.     

Dietary synbiotic supplementation improves the growth performance,body antioxidant pool,serum biochemistry,meat quality,and lipid oxidative stability in broiler chickens

The present study investigated the effects of Lactobacillus acidophilus (LBA) and mannan-oligosaccharides (MOS) supplementation on the production performance, serum biochemistry, antioxidant profile, health indices, meat quality, and lipid oxidative stability of broiler chicken. A total of 252 commercial broiler chickens at 1 d old of uniform body weight were randomly allocated to 6 maize-soybean-based dietary treatments: T₁ (control diet), T₂ ( antibiotic bacitracin methylene di-salicylate [BMD] at 20 mg/kg diet), T₃ (MOS at 0.1% + LBA at 10⁶ CFU/g feed), T₄ (MOS at 0.1% + LBA at 10⁷ CFU/g feed), T₅ (MOS at 0.2% + LBA at 10⁶ CFU/g feed), and T₆ (MOS at 0.2% + LBA at 10⁷ CFU/g feed). Each treatment was assigned to 6 replicates of 7 birds. The samples for meat quality and serum biochemistry analysis were taken from 12 birds per treatment (2 birds/replicate). The results revealed better (P < 0.01) growth performance and production efficiency of birds fed either T₅ or T₆ diet compared to control or BMD supplemented diet and BMD-supplemented birds superseded the control birds. Higher (P < 0.01) serum and liver antioxidant enzyme activities, meat antioxidant capacity (2, 2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid [ABTS] and 1, 1-diphenyl-2-picrylhydrazyl [DPPH] assays], serum total protein, high-density lipoproteins (HDL) cholesterol (P < 0.05), and globulin levels (P < 0.01) were observed in birds fed either T₅ or T₆ diet compared to control or BMD supplemented birds, whereas, lower lipid oxidation (P < 0.01), cardiac risk ratio, atherogenic coefficient, atherogenic index of plasma, serum glucose, triglyceride, total cholesterol levels (P < 0.01), and serum albumin-to-globulin ratio (P < 0.05) were observed in the chickens. The pH of meat from birds fed T₄, T₅ or T₆ diet was lower (P < 0.01) compared to control and other treatments. The extract release volume (ERV), water holding capacity (WHC), and protein content of meat were higher (P < 0.05) in birds fed either T₅ or T₆ diet compared to control or BMD supplemented birds. Thus, it was concluded that the supplementation of 0.2% MOS along with LBA at 10⁶ CFU/g is optimum for better growth performance, serum biochemistry, antioxidant profile, health indices, meat quality, and lipid oxidative stability of broiler chickens.     

Effect of a dietary supplementation with linseed oil and selenium to growing rabbits on their productive performances,carcass traits and fresh and cooked meat quality

The present experiment tested a dietary supplementation with linseed oil and selenium to growing rabbits. The basal diet (B) contained 3% sunflower oil, while it was substituted with 3% linseed oil in the experimental feed (S). The selenium (Se) content of the two diets was 0.10 vs. 0.46 mg/kg. Rabbits were fed with B diet from the age of 18 days. One group was fed with the B diet until 11 weeks of age (group B), whereas the experimental groups were fed with S diet for 1, 2, 3 or 4 weeks (groups S1, S2, S3 and S4, respectively), before slaughtering (11 weeks of age). Live performance and carcass traits of rabbits, fatty acid (FA) profile and selenium content of their hind leg (HL) and Longissimus thoracis et lumborum (LTL) meat were considered in this study. In addition, the effect of two different cooking methods on the nutritional value of the enriched HL meat was also assessed. The tested dietary supplementation only minimally affected the live performance and carcass traits of rabbits. The S supplementation significantly reduced the Σ n‐6 FA and increased the Σ n‐3 FA of the HL meat and LTL meat, compared to the B diet (p < 0.001); thus, n‐6/n‐3 ratio was improved (p < 0.001). In addition, HL meat and LTL meat of S fed rabbits were significantly enriched in Se reaching a twofold increase in both meat cuts (p < 0.01). Therefore, the S supplementation improved the functional value of the rabbit meat. The heat treatment affected cooking loss, Se and vitamin E contents as well as the oxidative status of the HL meat (p < 0.001), with the different cooking methods providing different results. In addition, even if the beneficial C20:5 n‐3 and C22:6 n‐3 decreased with cooking, the n‐6/n‐3 ratio remained unaffected.     

Live weights at slaughter significantly affect the meat quality and flavor components of pork meat

One‐hundred‐twenty crossbred pigs finished at 175–185 days of age were used to investigate the effects of live weights at slaughter on the meat quality, volatile flavor compounds, and sensory attributes of pork meat. Based on the live weights at slaughter, three weight groups (n = 36 per group) were classified as follows: light weight (LW: 100 kg), medium weight (MW: 110 kg), and heavy weight (HW: 120 kg). After slaughter, longissimus dorsi muscle samples were taken and used for the analyses of aforementioned parameters. The HW group had higher fat content and water holding capacity compared to the LW or MW group (p < 0.05). The HW group also showed higher levels for majority of unsaturated fatty acids and total polyunsaturated fatty acids than the LW group (p < 0.05). The slaughter weight significantly affected the amounts of 11 among the 47 flavor compounds identified. Significantly higher amounts of fatty acids oxidation‐derived flavor compounds (aldehydes) were found in the HW group than in the other groups. Noticeably, increasing slaughter weight was associated with higher sensorial scores for flavor, juiciness, and acceptance scores (p < 0.05). Based on the obtained results, 120 kg body weight is recommended as the market weight for this commercial breed without compromising the meat quality.     

Effect of a low‐voltage electrical stimulation on yak meat tenderness during postmortem aging

This study evaluates the effect of a low‐voltage electrical stimulation (ES) on the tenderness of yak longissimus muscle (LM). Samples from 16 yak bulls were divided into four treatment groups: normal chilling (NC), ES and chilling (ES & C) for 72 s (ES &C 72 s), ES & C for 90 s (ES & C 90 s), and ES & C for 108 s (ES & C 108 s). The temperature, the pH, the glycogen content, the Warner‐Bratzler shear force (WBSF), the myofibril fragmentation index (MFI), and the muscle ultrastructure were determined during the course of postmortem aging. ES caused a rapid decrease in the pH to form a high‐temperature and low‐pH environment. The glycogen content gradually decreased with aging. The WBSF value of the ES & C groups was significantly lower than for the NC group (p < .05). The MFI values of ES & C groups after 24 hr postmortem aging were significantly higher than for the NC group. We concluded that ES improved yak meat tenderness during postmortem aging and that the different duration time by ES indicated different effects, and its affect was remarkable in the ES & C 90 s.     

Effect of dietary nutmeg oil on heat‐stress tolerance‐related parameters in Korean native chicken reared under hot temperature

This study investigated the effect of dietary nutmeg oil (NO) on growth performance, blood parameters, lipid peroxidation and heat shock protein (HSP) 70 expression in Korean native chicken (KNC) reared under hot temperature. We allocated 273 meat‐type KNCs (Hanhyup‐3, 4‐week‐old, body weight [BW] = 539.93 ± 1.75 g) to the following three treatments with seven replicate pens (13 birds/pen) per treatment. Three treatment diets were as follows: (a) Control, basal diet without NO supplementation; (b) NO 250; and (c) NO 500, basal diet supplemented with 250 and 500 ppm NO respectively. Diets and water were provided ad libitum throughout the 6‐week feeding trial. During overall period (0–6 weeks), no differences (p > 0.05) were observed in BW gain (BWG), feed intake (FI) and feed conversion rate (FCR) among treatments. However, the FI at 0–3 weeks decreased (p < 0.05) quadratically with increasing NO levels. Most blood parameters did not differ (p > 0.05) among treatments, although the monocyte level of the NO 500 group was considerably lower (p > 0.05) than that of the other groups. Furthermore, dietary NO did not affect serum triglyceride, cholesterol, total protein, albumin, calcium, phosphorus and alanine aminotransferase (ALT) levels (p > 0.05); however, it linearly decreased serum aspartate aminotransferase (AST) level (p < 0.05). Additionally, serum malondialdehyde (MDA) concentration decreased (p < 0.05) and heart MDA concentration was lower (p = 0.08) with increasing dietary NO supplementation. After a 3‐hr heat (35°C) challenge, the rectal temperature (RT) reduced (p < 0.05) linearly with increasing NO levels. Dietary NO did not affect liver HSP70 (p > 0.05) gene expression. In conclusion, NO potentially enhanced the ability of chickens to alleviate heat stress. Furthermore, our findings suggest that lipid oxidation inhibition by dietary NO likely mediated the enhanced heat‐stress tolerance of the chickens.     

Phenotypic characteristics of upright and pendulous comb among chicken breeds and association with growth rate and egg production

Upright and pendulous combs commonly exist in most single‐comb chicken breeds. Here, the phenotypic characteristics of upright and pendulous combs in chickens and association with growth rate and egg production were analyzed. Phenotypic frequencies of upright and pendulous comb were investigated in five chicken breeds; the phenotypic frequencies of complete pendulous comb (CPC) and partial pendulous comb (PPC) ranged from 10.1% to 29.0% and 21.8% to 65.3%, respectively. CPC hens produced more eggs than PPC hens (P < 0.05) in Nongda‐3, Huainan and Wenchang breeds. In Huainan breed, CPC males were heavier than PPC males at 12 and 16 weeks of age, while CPC females were heavier at 24 weeks of age. PPC and CPC chickens have greater (P < 0.05) comb length, comb height and comb index than upright comb (UC) chickens. There was no significant difference in comb phenotypic frequency distribution between the offspring from UC(♂) × CPC(♀) and CPC(♂) × UC(♀); however, it differed (χ² = 45.12, P < 0.01) between offspring from UC(♂) × UC(♀) and CPC(♂) × CPC(♀). These results suggested that the comb phenotype does not appear to be Z‐linked; the effective loci influencing the trait could be estimated in a further study.     

Effect of dietary supplementation of hemp seed (Cannabis sativa L.) on meat quality and egg fatty acid composition of Japanese quail (Coturnix coturnix japonica)

This study was conducted in two separate experiments. Experiment I was conducted to investigate the effects of hemp seed (HS) on meat quality traits, and experiment II was designed to determine egg fatty acid (FA) composition in Japanese quail (Coturnix coturnix japonica). In experiment I and experiment II treatments, groups were as follows: (i) control (not included HS0), (ii) 5% HS inclusion to diets, (iii) 10% HS inclusion to diets and (iv) 20% HS inclusion to diets. In experiment I, a total of 192 7‐day‐old‐quail were fed with HS diets for 5 weeks, and end of the experiment I, a total of 64 quail (16 each) slaughtered and meat samples were analysed for meat colour, pH, cooking and thawing loss and FA composition. In experiment II, a total of 120 8‐week‐old laying quail were fed with experimental diets for 6 weeks and egg FA composition were determined. Breast meat cooking loss was significantly lower in 20% supplemented group (p < 0.01). Hemp seed inclusion to diets caused a linear and cubic increase in redness (a*) of hip meat (p < 0.01). Palmitoleic and oleic FAs were decreased with HS addition in breast meat (p < 0.05); however, linoleic and linolenic acid contents of meat were linearly increased (p < 0.01). In experiment II, the linoleic and linolenic FA contents of egg samples were linearly increased with increasing the dietary HS ratio (p < 0.01). Hemp seed addition was provided lower palmitoleic and oleic FAs in quail eggs (p < 0.05). In conclusion, HS supplementation to quail diets may increase quail meat redness and meat and egg yolk omega‐3 FA content and decrease cooking loss of quail meats.     

Effect of L‐theanine on meat quality,muscle amino acid profiles,and antioxidant status of broilers

This study investigated the effect of L ‐theanine on carcass traits, meat quality, muscle antioxidant capacity, and amino acid (AA) profiles of broilers. Three hundred 1‐day‐old Ross 308 male broilers were randomly allotted to five groups with six replicates. Birds were fed the basal diet or basal diet with 300, 600, 900, or 1,500 mg/kg L ‐theanine for 42 consecutive days. The results showed that L ‐theanine quadratically increased dressing percentage, eviscerated percentage, and leg muscle yield (p < .05). Meanwhile, drip loss, cooking loss, shear force, L*_24h, and muscle lactate content decreased quadratically in response to dietary L ‐theanine supplementation (p < .05), while pH_24h and muscle glycogen content were quadratically improved by L ‐theanine (p < .05). Notably, the contents of muscle malondialdehyde and protein carbonyl, and the activities of muscle total antioxidant capacity, catalase, and glutathione peroxidase decreased quadratically in response to dietary L ‐theanine supplementation (p < .05), suggesting that the oxidative stress level of muscle was decreased quadratically. Moreover, L ‐theanine quadratically increased the concentrations of most of muscle essential AA, nonessential AA, and flavor AA (p < .05). In conclusion, L ‐theanine can be used as a valuable feed additive to modulate carcass traits, meat quality, muscle antioxidant status, and AA profiles of boilers, and its optimum addition level is 600 mg/kg based on the present study.