• Asian-Australasian Journal of Animal Sciences
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• v.24 no.7
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• pp.1026-1030
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• 2011

An experiment was conducted to determine the effects of caponization on the muscle composition, ATP-related compounds, the shear values, the taste panel scores and the muscle fiber areas of Taiwan country chicken cockerels. At 10 wks of age, cockerels were divided into two groups: caponized and untreated. Birds were fed grower and finisher diets ad libitum in an eighteen-week experimental period. Results showed that capons contained significantly greater muscle fat content, less breast and thigh muscle moisture content, shear value and muscle fiber area (p<0.05) than those of intact birds. However, neither treatment groups differed significantly (p>0.05) in breast and thigh muscle protein content. Compared with the intact birds, the capons contained significantly (p<0.05) less muscle ash content in the breasts, but did not differ significantly (p>0.05) in thigh muscle ash content. The breast muscle IMP and ATP+ADP+AMP+IMP contents in the intact birds were significantly (p<0.05) higher than those in the capons. The intact birds had significantly (p<0.05) higher ATP and AMP contents than did the capons as well as significantly (p<0.05) less ADP and inosine (HxR) contents in the thigh and breast muscles. The Hypoxanthine (Hx) content of the thighs in the intact birds was significantly (p<0.05) higher than that in the capons; however, there was an adverse effect on the breast muscle Hx content. The breast muscle K value in the intact birds was significantly (p<0.05) lower than that in the capons. The capons produced significantly (p<0.05) higher taste panel scores than did the intact birds for both flavor and juiciness of thigh muscle as well as for flavor and tenderness of breast muscle.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.3
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• pp.401-405
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• 2002

An experiment was conducted to determine the effects of caponization on the growth performance, breast and thigh muscles physical properties and fiber diameter of the Pectoralis major and Gastrocnemius pars externa in Taiwan country chicken cockerels. Caponized birds were surgically altered at 10 weeks of age. Birds were fed grower and finisher diets ad libitum during an eighteen-week experimental period. The results indicated that the live weight and feed intake in the capons were significantly (p<0.05) higher and the shank length was significantly (p<0.05) longer than in intact birds. There were no significant (p>0.05) differences in feed conversion and mortality between two treatments at 28 weeks of age. Compared with intact birds, the capons had greater (p<0.05) tenderness in the breast and thigh muscles. Cohesion of the breast muscle in the capons was significantly (p<0.05) better than in the intact birds, but the thigh muscles were not significantly (p>0.05) affected. No treatment differences (p>0.05) were associated with cooking loss, muscle chewiness, and elasticity. The capons had a significantly (p<0.05) smaller fiber diameter in the Pectoralis major, but were not significantly (p>0.05) different in the fiber diameter of the Gastrocnemius pars externa. It is concluded that castration did not depress growth compared with the intact birds, but did improve muscle tenderness. This difference was most pronounced in the thigh muscles.

• Animal Bioscience
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• v.34 no.7
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• pp.1193-1201
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• 2021

Objective: According to market demand, meat duck breeding mainly includes 2 breeding directions: lean Pekin duck (LPD) and fat Pekin duck (FPD). The aim of the present study was to compare carcass and meat quality traits between 2 strains, and to provide basic data for guidelines of processing and meat quality improvement. Methods: A total of 62 female Pekin ducks (32 LPDs and 30 FPDs) were slaughtered at the age of 42 days. The live body weight and carcass traits were measured and calculated. Physical properties of breast muscle were determined by texture analyzer and muscle fibers were measured by paraffin sections. The content of inosine monophosphate (IMP), intramuscular fat (IMF) and fatty acids composition were measured by high-performance liquid chromatography, Soxhlet extraction method and automated gas chromatography respectively. Results: The results showed that the bodyweight of LPDs was higher than that of FPDs. FPDs were significantly higher than LPDs in subcutaneous fat thickness, subcutaneous fat weight, subcutaneous fat percentage, abdominal fat percentage and abdominal fat shear force (p<0.01). LPDs were significantly higher than FPDs in breast muscle thickness, breast muscle weight, breast muscle rate and breast muscle shear force (p<0.01). The muscle fiber average area and fiber diameter of LPDs were significantly higher than those of FPDs (p<0.01). The muscle fiber density of LPDs was significantly lower than that of FPDs (p<0.01). The IMF of LPDs in the breast muscle was significantly higher than that in the FPDs (p<0.01). There was no significant difference between the 2 strains in IMP content (p>0.05). The polyunsaturated fatty acid content of LPDs was significantly higher than that of FPDs (p<0.01), and FPDs had higher saturated fatty acid and monounsaturated fatty acid levels (p<0.05). Conclusion: Long-term breeding work resulted in vast differences between the two strains Pekin ducks. This study provides a reference for differences between LPD and FPD that manifest as a result of long-term selection.

• Animal Bioscience
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• v.34 no.11
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• pp.1829-1838
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• 2021

Objective: The effects of maternal dietary energy levels on breast muscle fibre development in offspring of broiler breeders were investigated. Methods: A total of 480 20-week-old Arbor Acres (AA) healthy female broiler breeders, with an average body weight of 2.33±0.01 kg, were randomly divided into 4 treatment groups with 6 replicates and 20 broiler breeders for each replicate and fed a corn and soybean meal diet with 100%, 80%, 70%, and 50% energy levels, respectively. Approximately 300 eggs per treatment were collected for incubation for 6 days. Then, 120 0-day-old female broilers at each energy level were randomly selected and divided into 6 replicates with 20 broilers for each replicate, with this experimental phase with the offspring lasting for 49 days. Results: Compared with the 100% energy group, the breast muscle fibre diameter at embryonic day 21 in the 80% energy group was significantly reduced (p<0.05). In the 80% energy group, the muscle fibre density of the breast increased significantly (p<0.05) at embryonic days 15 and 21. The breast muscle fibre diameter of the offspring in each group was significantly decreased (p<0.05) on the 1st day. The breast muscle sarcomere length of the embryos in the 80% energy group was significantly higher (p<0.05) than those in the 70% and 50% energy groups. Compared with the 100% energy group, the expression of the myostatin gene in the offspring was significantly decreased (p<0.05). Conclusion: In conclusion, the effects of a maternal dietary energy level of 80% in this study were found to be optimal for breast muscle fibre development in offspring, which indicated that the metabolic energy level of AA broilers of 9.36 MJ/kg for the mid-term diet for laying eggs has a more practical significance.

• Food Science of Animal Resources
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• v.41 no.5
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• pp.788-801
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• 2021

This study examined biochemical components, fatty acids, antioxidant dipeptides, and muscle fiber density of breast and thigh muscles from Korean new native chicken strains (A and B) at two slaughter ages, compared with white semi-broiler (W) or broilers. The pH values were different by chicken breed. The new native strains had the lowest fat content in the breast at 12 wk (p<0.05). Regardless of the muscles, A and B at 12 wk had higher levels of arachidonic acid (ARA; C20:4), docosahexaenoic acid (DHA; C22:6), and nervonic acid (C24:1) than broilers (p<0.05). A similar result was observed for the polyunsaturated fatty acids (PUFAs) and polyunsaturated and saturated fatty acids ratio (P/S) content in the breast. Irrespective of the muscles, A and B enriched with omega-3 fatty acids had a lower ω-6/ω-3 PUFA ratio than broilers (p<0.05) at 12 wk. Of the antioxidant di-peptides, the anserine contents were highest in A and B than in the W or broilers (p<0.05), regardless of the muscles and slaughter ages. Furthermore, the breast meat from A and B contained a higher muscle fiber density for both slaughter ages than the W and broilers (p<0.05). Based on these findings, even if the commercial birds (broilers or W) are raised under the similar environmental conditions as A and B, the new native chicken strains have distinct meat quality attributes, particularly higher ARA and DHA levels, lower ω-6/ω-3 PUFA ratio, and higher anserine contents.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.6
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• pp.884-888
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• 2003

Proteolytic enzymes are used for meat tenderization, an important process with regard to consumer preference. The proteolytic enzyme, IVRIN was isolated from the plant Cucumis pubescens W and its effect on physico-chemical properties and lipid profile of thigh and breast muscle of culled, desi and broiler birds was studied. Fifty-gram meat was treated with IVRIN containing 32.5 mg enzyme protein at $60^{\circ}C$ for 20 min. The pH of IVRIN treated meat was decreased significantly (p<0.01) and the effect was more pronounced in breast than thigh muscle. The water holding capacity (WHC) was increased significantly (p<0.01) in broiler as compared to desi and culled bird, and in breast compared to thigh muscle. IVRIN failed to produce any impact on muscle fiber diameter (MFD). The MFD of desi was significantly higher (p<0.01) than broiler and culled birds. The total lipid concentration in thigh and breast muscle of desi was lower (p<0.01) than broiler and culled birds, latter being similar in this respect. The cholesterol content was lower (p<0.01) in breast than thigh muscle, in broiler than desi and culled and in IVRIN treated than untreated meat samples. The phospholipid concentration was unaffected by IVRIN. Broiler and culled birds exhibited more phospholipid content than desi birds.

• Animal Bioscience
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• v.34 no.4
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• pp.652-661
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• 2021

Objective: Wooden breast (WB) is a novel myopathy affecting modern broiler chickens, which causes substantial economic losses in the poultry industry. The objective of this study was to evaluate the effect of WB abnormality on meat quality, redox status, as well as the expression of genes of the nuclear factor-erythroid 2-related factor 2 (Nrf2) pathway. Methods: A total of 80 broilers (Ross 308, 42 days of age, about 2.6 kg body weight) raised at Jiujin farm (Suqian, Jiangsu, China) were used. Twelve unaffected (no detectable hardness of the breast area) and twelve WB-affected (diffuse remarkable hardness in the breast muscle) birds were selected from the commercial broiler farm according to the criteria proposed by previous studies. Results: The results indicated that WB showed histological lesions characterized by fiber degeneration and fibrosis, along with an increase of muscle fiber diameter (p<0.05). Moreover, higher pH value, lightness, yellowness, drip loss and cooking loss were observed in the WB group (p<0.05). Compared with the normal breast (NOR) group, the WB group showed higher formation of reactive oxygen species (p<0.05), increased level of oxidation products and antioxidant activities (p<0.05), accompanied with mitochondrial damages and lower mitochondrial membrane potential (p<0.05). Meanwhile, the relative mRNA expressions of Nrf2 and its downstream antioxidant genes including heme oxygenase-1, NAD(P)H qui none dehydrogenase 1, glutathione peroxidase, superoxide dismutase, and glutamate-cysteine ligase were higher than those of the NOR group (p<0.05). Conclusion: In conclusion, WB myopathy impairs meat quality by causing oxidative damages and mitochondrial dysfunction in broilers, even though the activated Nrf2/antioxidant response element pathway provides protection for the birds.

• Food Science of Animal Resources
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• v.35 no.1
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• pp.101-107
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• 2015

The aim of this study was to investigate the effects of various marination processes on the quality characteristics of chicken breast prepared with chicken feet gelatin and wheat fiber. The chicken feet gelatin was swollen with hydrochloric solution (0.1 N HCl, pH $1.31{\pm}0.02$) and dehydrated by freeze-drying. The composition (w/w) of the marinade was water (10%), soy sauce (12%), phosphate (0.3%), wheat fiber (1.5%), and chicken feet gelatin (1.5%). Three samples of chicken breast were manufactured with Tumbler (only tumbler), Tenderizer (tenderizer and tumbler), and Injector (injector and tumbler). The water content of the Injector sample was significantly higher than those of the Tumbler and Tenderizer samples (p<0.05). During heating, the lightness of all chicken breasts increased and the redness decreased. The tumbling and cooking yield of the Injector sample were significantly higher than those of the Tumbler and Tenderizer samples (p<0.05). The shear force of the Tenderizer sample was significantly lower than that of the Tumbler and Injector samples (p<0.05). No significant differences, except for color, were observed in the sensory analysis of the samples. Thus, the proper selection of mechanical processing is important to improve the quality characteristics of marinated chicken breast, considering the types of final products.

• Korean Journal of Poultry Science
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• v.49 no.1
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• pp.33-43
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• 2022

The present study was conducted to determine the effect of reduced dietary crude protein (CP) with a synthetic indispensable amino acids (AA) supplement on the growth performance, economics, and breast meat quality. A total of 450 male broilers (Ross 308) were used from the age of 7 to 28 days. On d 7, the birds were individually weighed and randomly assigned to three treatment diets with six replicate pens for each treatment in a randomized complete block design. The experimental diets were: (1) a control diet, (2) a diet with a reduction of 1% of the dietary CP with synthetic AA supplements to meet the indispensable AA requirement (OAA) of broiler chickens, and (3) a diet with a reduction of 1% of the dietary CP with synthetic Lys, Met, and Thr supplementation to exceed 5% of the indispensable AA requirement (HAA). There were no differences among the treatments on the final body weight, weight gain, and feed intake. However, the HAA diet impaired the feed conversion ratio at d 21 and during the overall feeding periods (P<0.05). The predicted total feed intake and feed price required to reached 1.5 kg BW was higher than for the birds fed the HAA diet (P<0.05). The breast meat muscle fiber cross sectional area and fiber density varied between the treatments (P<0.05). However, there were no differences in breast meat weight. In conclusion, reducing 1% of dietary CP had no adverse effects on the growth performance or breast meat yields.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.5
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• pp.701-710
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• 2019

Objective: This study investigated the effect of different acute heat stress (HS) levels on chicken meat quality and ultra-structure. Methods: Chickens were randomly divided into 7 groups to receive different HS treatments: i) $36^{\circ}C$ for 1 h, ii) $36^{\circ}C$ for 2 h, iii) $38^{\circ}C$ for 1 h, iv) $38^{\circ}C$ for 2 h, v) $40^{\circ}C$ for 1 h, vi) $40^{\circ}C$ for 2 h, and vii) un-stressed control group ($25^{\circ}C$). Blood cortisol level, breasts initial temperature, color, pH, water holding capacity (WHC), protein solubility and ultra-structure were analyzed. Results: HS temperatures had significant effects on breast meat temperature, lightness ($L^*$), redness ($a^*$), cooking loss and protein solubility (p<0.05). The HS at $36^{\circ}C$ increased $L^*{_{24h}}$ value (p<0.01) and increased the cooking loss (p<0.05), but decreased $a^*{_{24h}}$ value (p<0.05). However, as the temperature increased to $38^{\circ}C$ and $40^{\circ}C$, all the values of $L^*{_{24h}}$, cooking loss and protein denaturation level decreased, and the differences disappeared compared to control group (p>0.05). Only the ultimate $pH_{24h}$ at $40^{\circ}C$ decreased compared to the control group (p<0.01). The pH in $36^{\circ}C$ group declined greater than other heat-stressed group in the first hour postmortem, which contributed breast muscle protein degeneration combining with high body temperature, and these variations reflected on poor meat quality parameters. The muscle fiber integrity level in group $40^{\circ}C$ was much better than those in $36^{\circ}C$ with the denatured position mainly focused on the interval of muscle fibers which probably contributes WHC and light reflection. Conclusion: HS at higher temperature (above $38^{\circ}C$) before slaughter did not always lead to more pale and lower WHC breast meat. Breast meat quality parameters had a regression trend as HS temperature raised from $36^{\circ}C$. The interval of muscle fibers at 24 h postmortem and greater pH decline rate with high body temperature in early postmortem period could be a reasonable explanation for the variation of meat quality parameters.