Pectoralis Major Muscle Weight Research Articles

Effects of a myostatin mutation in Japanese quail (Coturnix japonica) on the physicochemical and histochemical characteristics of the pectoralis major muscle.

The aim of this study was to compare the carcass, meat quality, and histochemical characteristics of pectoralis major (PM) muscle between wild type (WT) and myostatin (Mstn) homozygous mutant (HO) quail lines. The HO quail line exhibited significantly heavier body weight (HO vs. WT, 115.7g vs. 106.2g, approximately 110%) and PM muscle weight (HO vs. WT, 18.0g vs. 15.2g, approximately 120%) compared to the WT (p < 0.001). However, the two groups had similar traits (pH, redness, yellowness, and drip loss) for meat quality, although slightly higher lightness and cooking loss were observed in the mutant quail (103% and 141%, respectively, p < 0.05). For histochemical traits of PM muscle, Mstn mutant quail exhibited lower type IIA and higher type IIB percentage in the deep region than WT quail (p < 0.05), indicating a fiber conversion from the type IIA to IIB. However, the two quail lines had comparable histochemical traits in the superficial region (p > 0.05). These data suggest that Mstn mutation greatly increases muscle mass without significantly affecting meat quality.

Administration of Branched-Chain Amino Acids in the Pre- or Post-Hatch Period Improves the Fiber Characteristics of Pectoralis major Muscle in Turkey Poults Subjected to Early or Delayed Feeding

Poultry meat quality is controlled by muscle fiber properties associated with body weight gain in the immediate pre- or post-hatch period. This study aimed to determine the effect of administration of branched-chain amino acids blend (BCAAb, 3 L-leucine:1 L-isoleucine:2 L-valine) in the pre- or post-hatch period on the growth performance and fiber characteristics of the Pectoralis major (PM) muscle in turkey poults subjected to early or delayed feeding. Newly hatched poults from eggs injected in ovo with BCAAb or received no injection were used in a 21-d study. Poults (n=192) produced without injection of BCAAb received a starter diet supplemented (BCAA) or not (C) with the BCAAb (2 g/kg) immediately or with a delay of 48 h (48BCAA and 48C) after hatching. Poults (n=36) produced with (IOBCAA) in ovo injection of BCAAb (2 mg /ml) received the diet and water immediately. The BCAA and IOBCAA poults had higher body weight than those of the C, 48C, and 48BCAA birds. The body weight of the C poults was higher than those of the 48C and 48BCAA birds. The BCAA poults had higher PM muscle weight than those of the C and 48C poults, while that of the IOBCAA poults was higher than that of the 48C poults. The IOBCAA treatment increased the protein content of the PM muscle meat, compared with the C and 48C treatments. The 48C treatment increased the type IIB fiber area and the type I and type IIA fiber percentages but decreased the type IIB fiber, compared with other treatments. The numbers of type IIB and total fibers in the IOBCAA poults were higher than those of the 48C birds. In conclusion, administering BCAAb in ovo or in a starter diet enhanced early growth performance and improved the fiber characteristics of the PM muscle in turkey poults.

529 Late-Breaking: Effects of in Ovo Injection of High Yield Broilers with Nicotinamide Riboside on Pectoralis Major Morphometrics, Muscle Fiber Density, and mRNA Expression

Abstract The objective of this study was to determine the effects of in ovo injection of high yield broilers with nicotinamide riboside (NR) on broiler pectoralis major muscle (PMM) development, growth, and mRNA expression. Fertilized Cobb 700 broiler eggs were randomly assigned to 1 of 4 treatments within a 2×2 factorial design with NR dose (DOS; 0 or 2.5 mM) and injection location (LOC; albumen or yolk) as main effects. Eggs were injected with their assigned treatment at d 10 of incubation. Day-15 and -18 embryos and hatched chicks were euthanized, right PMM and muscle fiber morphometric measurements were collected, and left PMM were utilized for mRNA expression analysis of sirtuin-1 and cyclin D1, 2 and 3. There were no LOC×DOS interactions or main effects for d-15 and -18 PMM measurements (P &amp;gt; 0.23). There were LOC×DOS interactions for hatched chick PMM weight and length, and muscle fiber density (P &amp;lt; 0.04). When NR was injected into the albumen, PMM weight decreased (P = 0.02) and length and fiber density were unaffected (P &amp;gt; 0.33), while PMM weight and fiber density increased when NR was injected into the yolk (P &amp;lt; 0.05). There were no LOC×DOS interactions for all genes analyzed for d-15 and 18-embryos (P &amp;gt; 0.23), but NR embryos had greater expression of all genes (P &amp;lt; 0.03) except d-18 cyclin-D2 (P = 0.08). There were LOC×DOS interactions for hatched chick expression of all genes (P &amp;lt; 0.04). There was no difference in sirturin-1 expression when chicks were injected with 0 mM NR, but 2.5-mM yolk chicks had greater expression than 2.5-mM albumen chicks. When NR was injected into the albumen, expression of all cyclins was unaffected (P &amp;gt; 0.08), while expression increased when NR was injected into the yolk (P &amp;lt; 0.01). Increased expression of sirturin-1 and the cyclins may be responsible for NR catalyzed increase in PMM weight and fiber density.

Research Note: Expression level of heat shock protein 27 in PSE-like and fast-glycolyzing conditions of chicken pectoralis major muscle

This study compared the meat quality traits, histochemical characteristics, and heat shock protein (HSP) 27 expression levels of the broiler Pectoralis major (PM) muscles in groups classified by pale, soft, and exudative (PSE)-like and fast-glycolyzing conditions using the lightness and muscle pH change values. Chicken PM muscles showing higher pH change value and paler meat surface (as HP group) could be associated with the PSE-like condition, and exhibited a lower pH24 h value and higher cooking loss compared to PM muscles showing lower pH change value and normal color (as LN group) (P < 0.05). Greater PM muscle weight and fiber area were observed in the HP group compared to the other groups (P < 0.05); meanwhile, the PM muscles showing higher pH change value with normal color (as HN group) and the PM muscles showing lower pH change value with paler color (as LP group) did not differ in the water holding capacity, Warner-Bratzler shear force, and muscle fiber characteristics (P > 0.05). Muscle samples showing a higher pH change value exhibited a greater level of HSP27 compared to muscle samples showing a lower pH change value (P < 0.05). Therefore, the current findings suggested that the expression level of HSP27 can be a useful indicator for explaining variations in the glycolytic rate of chicken breast muscle.

Research Note: Comparison of histochemical characteristics, chicken meat quality, and heat shock protein expressions between PSE-like condition and white-stripping features of pectoralis major muscle

The present study compared the histochemical and meat quality characteristics of broiler pectoralis major (PM) muscle among the groups categorized according to muscle abnormalities, including pale, soft, and exudative (PSE)-like condition and white-striping (WS) feature. Additionally, this study investigated the associations between muscular abnormalities and expression levels of heat shock proteins (HSPs), including αβ-crystallin, HSP70, and HSP90, at the early postmortem period. The WS breasts with normal quality condition showed greater PM muscle weight and were more associated with fiber hypertrophy, compared to the no WS breasts with PSE-like condition (P < 0.05). The PSE-like group exhibited paler surface color and tougher meat, causing more fluid loss after cooking, compared to the normal quality group (P < 0.05). However, there were no significant differences in the quality traits between the WS groups (P > 0.05), except for lightness and cooking loss. Higher αβ-crystallin and HSP90 expression levels were observed in PSE-like breast compared to normal quality breast (P < 0.05), whereas WS pattern was not related with HSPs levels (P > 0.05). Therefore, HSP levels at the early postmortem period, especially those of αβ-crystallin and HSP90, were associated with the breast quality characteristics of PSE-like condition broilers.

Effect of dressing percentage on chemical composition, microstructure and quality traits of Pectoralis major muscle in female Japanese quail

Summary The experiment involved 40 female Japanese quail ( Coturnix japonica) slaughtered at 8 weeks of age. The study was arranged to determine slaughter traits, physicochemical properties and microstructure characteristics of Pectoralis major muscle as related to the different dressing percentages, and to examine the correlation between tested parameters. The results show that dressing percentage significantly affected carcass and Pectoralis major muscle weight, acidity and the content of crude fat, dry matter and soluble collagen. Dressing percentage did not influence the number of fast-twitch oxidative-glycolytic muscle fibres, cross-section area for slow-twitch oxidative fibres and aerobic index. Dressing percentage was positively and significantly correlated with the number of fibres and capillaries per bundle, the quantity of fast-twitch glycolytic fibres, cross-section area for fast-twitch oxidative-glycolytic fibres, anaerobic index and fat content in the muscle. Only in the case of the number of slow-twitch oxidative fibres the correlation coefficient was negative and the relationship with dressing percentage significant. It is concluded that it is possible to obtain high-quality meat with increased dressing percentage from 8-week-old female Japanese quail.

Comparative growth performance in different Japanese quail lines: The effect of muscle DNA content and fiber morphology

The aim of this study was to investigate the DNA content and morphological characteristics of muscle fibers, and their relation to the growth performance in random bred control (RBC) and heavy weight (HW) Japanese quail lines. The 2 lines were of similar embryo size at 6 and 8 d of incubation; however, HW quail were significantly larger than their counterparts after 10 d of incubation (P < 0.05). The hatch weight of the HW quail line was approximately 1.3-fold higher than the RBC quail line (P < 0.001). After 15 d posthatch, the BW and pectoralis major muscle weight (PMW) exhibited remarkable differences between the 2 quail lines. The RBC line showed a faster rate of increase in PMW (2.7- vs. 2.1-fold) and total DNA mass (2.2- vs. 1.6-fold) between 0 and 4 d posthatch. The HW line exhibited a greater rate of the PMW (33.0- vs. 12.9-fold) and total DNA mass (10.3- vs. 4.0-fold) between 4 and 15 d posthatch than the RBC line. Moreover, the greatest increase in total DNA mass occurred between 0 and 8 d posthatch for the RBC line and 4 to 15 d posthatch for the HW line. These differences in the DNA content indicate a difference in the hypertrophic potential of muscle fibers between the 2 quail lines. The cross-sectional area of muscle fibers was 1.3-fold greater in the HW line compared with the RBC line at 8 d posthatch (158.5 vs. 97.11 μm(2), P < 0.001), and this difference increased with age (over 2.1-fold greater in the HW line). Thus, the most important time windows affecting ultimate body and muscle weights in the RBC and HW quail lines are between 0 to 8 d and 4 to 15 d posthatch, respectively. Rapid muscle growth rate and a greater muscle mass in the HW quail line may be partially due to the hypertrophic potential of muscle fibers, which is characterized by larger fiber size.

Maternal low-protein diet programmes offspring growth in association with alterations in yolk leptin deposition and gene expression in yolk-sac membrane, hypothalamus and muscle of developing Langshan chicken embryos

The present study was aimed to investigate the mechanism underlying the influence of maternal low-protein (LP) diet on offspring growth in the chicken. One hundred and twenty Chinese inbred Langshan breeder hens were allocated randomly into two groups fed diets containing low (10%, LP) or normal (15%) crude protein levels. Low dietary protein did not affect the body weight of hens, but significantly decreased the laying rate and egg weight. The yolk leptin content was significantly lower in eggs laid by LP hens, while no differences were detected for yolk contents of corticosterone, tri-iodothyronine (T3) or thyroxine. Despite significantly lower hatch weight, the LP offspring demonstrated obviously higher serum T3 concentration, which is in accordance with the faster post-hatch growth rate achieving significantly heavier body weight and pectoralis major muscle weight 4 weeks post-hatching. Expression of 20-hydroxysteroid dehydrogenase (20-HSD) mRNA in the yolk-sac membrane was significantly down-regulated at embryonic day 14, whereas that of transthyretin and leptin receptor (LepR) was not altered. Moreover, hypothalamic expression of 20-HSD, glucocorticoid receptors, thyrotropin-releasing hormone and LepR mRNA was significantly up-regulated in the LP group compared with their control counterparts. In the pectoralis major muscle, significantly higher expression of insulin-like growth factor (IGF)-I and IGF-I receptor mRNA was observed in LP embryos. The present study provides evidence that maternal LP diet programmes post-hatch growth of the offspring. The associated alterations in yolk leptin deposition as well as in yolk-sac membrane, fetal hypothalamus and muscle gene expression may be involved in mediating such programming effect in the chicken.

The Influence of Selection for Increased Body Weight and Sex on Pectoralis Major Muscle Weight During the Embryonic and Posthatch Periods

Skeletal muscle development and growth results from a complex series of highly organized processes. To address how myogenesis was influenced by selection for increased BW and by sex, both sexes from a turkey line (F) selected only for increased 16-wk BW and its genetic control line (RBC2) were used. Pectoralis major muscle was isolated and weighed from 15 individuals of each sex of the F and RBC2 lines at 14, 16, 18, 20, and 24 d of embryonic development and at 1, 8, 12, and 16 wk of age posthatch. The F line had significantly heavier p. major muscle weights than the RBC2 line beginning at 16 d of embryonic development, and the magnitude of the line differences generally increased with age through 16 wk posthatch The p. major muscle was consistently heavier in males than in females, but the differences between sexes were significant only at 16, 18, and 24 d of embryonic development and at 8 wk posthatch. There was no significant interaction between line and sex for weight of the p. major muscle at any age. The results indicated that selection for increased 16-wk BW in the F line altered growth of the p. major muscle by 16 d of embryonic development and changes were similar for both sexes.

Muscle protein turnover during early development in chickens divergently selected for growth rate

To explore the mechanisms involved in the genetic control of muscle growth and protein gain, protein metabolism was assessed in the pectoralis major muscle of two chicken lines selected for either fast or slow growth. Protein synthesis was measured in vivo at various ages from 1 to 4 wk, using a flooding dose of L-[4-3H] phenylalanine. Protein degradation was estimated as the difference between synthesis and deposition. Over the experimental period, BW were about 2-fold greater (P < 0.001), and pectoralis major muscle weights were 2.4- to 3.6-fold higher (P < 0.001), in chicks from the fast-growing line (FGL) than those from the slow-growing line (SGL). Independent of age, absolute rates of protein deposition, synthesis, and breakdown were higher in FGL than in SGL chickens. Fractional rates of muscle protein synthesis clearly decreased with age. When comparing birds of the same age, fractional rates of muscle protein synthesis tended to be lower in the FGL. Fractional degradation rates (KD) were significantly lower in FGL chickens during the first 2 wk of post-natal growth, whereas KD were similar between lines in older chickens. In this experimental model of chicken lines divergently selected for BW, the greatest line-related difference in muscle protein metabolism was in KD, and was observed in the early growth phases.