•Wooden breast has a high mechanical strength even 5 days after slaughter.•Myofibrils weakening after slaughter hastens myofibrillar fragmentation in wooden breast.•Connective tissues in such breast ...were unchanged during postmortem aging till day 5.•The stiffness in wooden breast can be contributed to unchanged connective tissues.
Wooden breast is a common problem in the poultry industry, occurring when broiler breast meat becomes rubber-like and extremely hard. Unclear points remain regarding the mechanical strength changes caused by post-mortem biochemical changes in wooden breasts. This study aimed to investigate this knowledge gap. We found endogenous protease activity to be high in wooden breasts and observed a 30 kDa fragment of troponin T (an indicator of postmortem tenderness) from day 1 postmortem. The amount of intramuscular connective tissue in wooden breasts was greater than that of normal breast meat, particularly in the perimysium. The intramuscular connective tissue structure and quantity significantly affect the mechanical strength of meat. It became clear that the wooden breasts are much more mechanically stronger than normal breasts at postmortem day 5 because the large amount of intramuscular connective tissue in the wooden breasts has hardly changed even 5 days postmortem.
The muscular dystrophies comprise more than 30 clinical disorders that are characterized by progressive skeletal muscle wasting and degeneration. Although the genetic basis for many of these ...disorders has been identified, the exact mechanism for pathogenesis generally remains unknown. It is considered that disturbed levels of reactive oxygen species (ROS) contribute to the pathology of many muscular dystrophies. Reactive oxygen species and oxidative stress may cause cellular damage by directly and irreversibly damaging macromolecules such as proteins, membrane lipids and DNA; another major cellular consequence of reactive oxygen species is the reversible modification of protein thiol side chains that may affect many aspects of molecular function. Irreversible oxidative damage of protein and lipids has been widely studied in Duchenne muscular dystrophy, and we have recently identified increased protein thiol oxidation in dystrophic muscles of the mdx mouse model for Duchenne muscular dystrophy. This review evaluates the role of elevated oxidative stress in Duchenne muscular dystrophy and other forms of muscular dystrophies, and presents new data that show significantly increased protein thiol oxidation and high levels of lipofuscin (a measure of cumulative oxidative damage) in dysferlin‐deficient muscles of A/J mice at various ages. The significance of this elevated oxidative stress and high levels of reversible thiol oxidation, but minimal myofibre necrosis, is discussed in the context of the disease mechanism for dysferlinopathies, and compared with the situation for dystrophin‐deficient mdx mice.
Disturbed levels of reactive oxygen species are believed to contribute to the pathology of many muscular dystrophies. New data are presented that show significantly increased protein thiol oxidation and high levels of lipofuscin (a measure of cumulative oxidative damage) in dysferlin‐deficient muscles of A/J mice at various ages. The significance of this is critically compared with dystrophin‐deficient mdx mice.
The high incidence of meat of impaired quality poses a serious problem in the poultry industry. In recent years, the incidence of the pectoralis major muscle that appeared pale colored, remarkably ...hardened, and exudative, called "wooden breast" or "woody breast" has increased in slaughter houses. In the present study, 19-day-old Ross 308 broiler chickens affected (n = 10) and unaffected (n = 10) with remarkably hardened breast were selected from a commercial broiler farm, and reared to 55 days of age under a controlled environment. Among the affected birds, 5 of 10 birds appeared exhausted with markedly suppressed weight gain and 4 of 10 birds died during the rearing period. In contrast, all unaffected birds survived and most gained weight. Four of 10 unaffected birds lost the ability of back-to-back wing contact by the late stage of rearing. The biochemical analysis of blood plasma samples of 20-day-old birds revealed that creatine kinase and L-aspartate aminotransferase values in most affected birds were higher than those in unaffected birds; however, these values in unaffected birds increased rapidly with lost wing contactability and increasing age. Postmortem examinations revealed that the mean diameter of myofibers in affected birds was smaller than that in unaffected birds. Moreover, symptoms of degenerative and regenerative muscles were observed in most birds in both groups. Among them, a decrease in, or defect of, the characteristic polygonal shape of myofibers was the most common change within the pectoralis major muscles in both groups. The present study demonstrated that broilers affected with remarkably hardened breast during the middle stage of rearing would have suppressed physical status and weight gain, or would die. It was suggested that rapid growth in broilers might be a cause of remarkably hardened breast.
The growth rate of broiler chickens has increased by 400% over the past 50 years, and breast yields continue to increase. This has led to an increase in thoracic muscle abnormalities in broilers, ...with wooden breast becoming a major issue worldwide. The etiology and the mechanism underlying the etiology of wooden breasts have not yet been elucidated; however, it occurs due to oxidative stress. Reactive oxygen species, which cause oxidative stress, are mainly produced in mitochondria. Thus, in this study, we investigated the relationship between the severity of wooden breast in broilers and the characteristics of mitochondria as the source of reactive oxygen species. Sampling of the pectoralis major muscle at the ventral cranial position was conducted in 50-day-old broilers. The severity of wooden breast was classified into three groups based on the muscle fiber roundness and wing–wing contact test, with highest severity in severe wooden breast and lowest severity in normal breast. Nicotinamide adenine dinucleotide tetrazolium reductase staining revealed an increase in darkly stained muscle fibers, indicating high severity of wooden breast. The mitochondria were swollen in severe wooden breast cases, with highest swelling in severe wooden breast and lowest swelling in normal breast. The expression levels of the mitochondrial antioxidant enzyme genes superoxide dismutase 1 and superoxide dismutase 2 were significantly lower in wooden breast-severe tissue than in normal tissue. These results suggest that when the levels of reactive oxygen species in muscle fibers, which should be constant, are increased, mitochondrial homeostasis is not maintained and the damage levels increase in various membranes of the cell, leading to the disruption of normal physiological functions.
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•Wooden breast affected muscle fibers were rounded as severity higher.•More myofibers were stained with dark and intermediate colors in wooden breast by NADH-TR staining.•Anti-ATPB immune staining were larger mitochondrial particles in severe cases compared with those in normal and mild cases.•The gene expression levels of SOD1 and SOD2 in wooden breast were significantly low.
The purpose of this study is to compare the assessment of pre- and postpartum oxidative stress-related causal indicators and other metabolites in cows with postpartum subclinical ketosis (SCK). The ...prepartum serum malondialdehyde concentration and body condition score (BCS) were elevated in the SCK cows (n=17) compared to healthy controls (n=12), while the insulin sensitivity check index was lower in the SCK cows than in the controls. Oxidative stress is enhanced in cows with prepartum higher BCS, causing decreased insulin sensitivity, and may be associated with onset of postpartum SCK. However, paraoxonase alone might be insufficient to assess the antioxidant state because of no difference in pre- and postpartum activities between the two groups.
This study investigated whether freezing or warming water-in-oil (W/O) vaccines affected the immune responses of chickens. One of the conditions affecting the efficacy of commercially available ...animal vaccines is the storage temperature range. Previous studies have shown that the properties of some inactivated vaccines change owing to freezing, leading to reduced immune responsiveness after inoculation. In this study, we first determined the freezing temperatures of a commercial W/O vaccine using freezers maintained at −10, −13, −15, and −20°C. The results showed that the W/O vaccine froze from −10 to −12°C. Next, we evaluated the effect on antibody level transitions (sample-to-positive ratio) in 46-day-old broiler chickens vaccinated with the W/O vaccine that was maintained at −20°C, 5°C, and −10°C, in that order. In addition, the effect on antibody value transitions was evaluated in 45-day-old broiler chickens vaccinated with the W/O vaccines that were frozen and thawed between −20°C and 5°C repeatedly or warmed to 42°C. In these experiments, no remarkable effect of the freeze-thawing or warming treatments on antibody value transitions was observed. These results suggested that the efficacy of the W/O vaccine was not significantly affected when placed in a frozen environment or left in a room temperature environment of 42°C or lower for approximately 5 d. These data indicate the possibility of expanding the temperature range for handling W/O vaccines.
Because of corneal transplantation limitations, there is a need for cornea-specific regenerative medicine. The development of such regenerative medicine has been delayed because of the complex and ...unique structure of the corneal stroma. Few studies have explored the corneal stroma cell distribution and cell types in vivo. This study investigated regional differences in morphological characteristics and distributions of corneal keratocytes and immunocompetent cells in the corneal stroma to clarify their functions and structural characteristics. The porcine eyeballs were subjected to light microscopy, transmission electron microscopy, scanning electron microscopy, and immunofluorescence staining analyses. Corneal cells were primarily located in the limbus, rather than the center of the cornea; the long keratocyte diameter was largest on the epithelial side of the corneal limbus, while the short diameter was largest on the endothelial side of the central cornea. Moreover, there were significantly more corneal cells on the epithelial side than on the endothelial side in both the central and limbus areas. Gap junctions between cells in the corneal stroma were present on the surfaces of cytoplasmic processes. Many cytoplasmic processes were scattered throughout the corneal stroma; they were connected both vertically and horizontally, forming an intercellular network. Additionally, immunocompetent cells on the epithelial side suggested to participate in this network via gap junctions. The morphology of keratocytes and immunocompetent cells on the epithelial side suggests that they play important roles in corneal homeostasis.
Cattle mange causes extreme itchiness, and the associated stress is an animal welfare concern that leads to economic losses due to decreased cattle productivity and deworming costs. This study ...investigated the reason why Chorioptic mites, C. bovis and C. texanus, preferentially infest the tail root region (rTR) and performed histological and biochemical analysis focusing on the volatile components of host odors that serve as the starting point for infestation of parasitic arthropods. Skin samples were taken from the rTR, lateral abdominal, and central masseteric, with the latter two designated as comparison sites. The two and three-dimensional histological analysis measured each sebaceous and sweat gland percentage per unit volume. The q-PCR analyzed the expression levels of ALDH1A1 and LOC785756, which are genes associated with volatile odoriferous compounds that serve as repellency and attractive messengers for ticks. Immunohistochemistry stained three sites with anti-androgen binding protein beta-like (ABPβ-like), encoded by LOC785756, antibody. The three-dimensional analysis showed that sebaceous glands in the rTR tend to be more continuous and existed in larger masses than in other regions. The expression level of LOC785756 was significantly higher in the rTR, and immunohistochemistry revealed the presence of ABPβ-like in the sebaceous gland with strong positive signals in the rTR. These results suggest that C. bovis/texanus selectively infests the rTR because that skin has well-developed sebaceous glands, including a large amount of ABPβ-like, which acts as a mite attractant.
Staphylococcus virus ΦSA012 has a wide host range and efficient lytic activity. Here, we assessed the biological stability of ΦSA012 against temperature, freeze-thawing, and pH to clinically apply ...the phage. In addition, inoculation of ΦSA012 through i.p. and i.v. injections into mice revealed that phages were reached the limit of detection in serum and accumulated notably spleens without inflammation at 48 h post-inoculation. Furthermore, inoculation of ΦSA012 through s.c. injections in mice significantly induced IgG, which possesses neutralizing activity against ΦSA012 and other Staphylococcus viruses, ΦSA039 and ΦMR003, but not Pseudomonas viruses ΦS12-3 and ΦR18 or Escherichia viruses T1, T4, and T7 in vitro. Immunoelectron microscopic analysis showed that purified anti-phage IgG recognizes the long-tail fiber of staphylococcus viruses. Although S. aureus inoculation resulted in a 25% survival rate in a mouse i.p. model, ΦSA012 inoculation (i.p.) improved the survival rate to 75%; however, the survival rate of ΦSA012-immunized mice decreased to less than non-immunized mice with phage i.v. injection at a MOI of 100. These results indicated that ΦSA012 possesses promise for use against staphylococcal infections but we should carefully address the appropriate dose and periods of phage administration. Our findings facilitate understandings of staphylococcus viruses for phage therapy.
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