The effect of transport stress on blood metabolism, glycolytic potential, and meat quality in broilers was investigated. Arbor Acres chicks (n = 360, 1 d old, males) were randomly allotted to 1 of 5 treatments: unstressed control, 45-min (short-term) transport with 45-min (short-term) recovery, 45-min transport with 3-h (long-term) recovery; 3 h (long-term) transport with 45-min recovery, and 3-h transport with 3-h recovery. Each treatment consisted of 6 replicates with 12 birds each. On d 46, all birds (except the control group) were transported according to a designed protocol. Transport time affected plasma glucose level (P<0.05) and glycogen level (P=0.06) in breast muscle as well as the area (P<0.01) and density (P<0.01) of IIa fibers. Glucose concentration increased slightly during the first 45 min of transport and then decreased dramatically in the long-term transported broilers (P<0.05). Long-term transport decreased the concentration of breast glycogen (P=0.06) and affected the size of IIa fibers in tibialis anterior by decreasing the area (P<0.01) with an increase in density (P<0.01). However, a long-term recovery after transport contributed to the homeostasis of blood corticosterone (CORT, P=0.05) and low levels of glycogen (P<0.05), lactate (P<0.01), and glycolytic potential (P<0.01) in thigh muscles. Interactions existed between transport and recovery time on area (P<0.05) and density (P<0.01) of IIa fibers. Furthermore, plasma nonesterified fatty acids increased significantly in the 3-h transport with 3-h recovery group (P<0.05) in comparison with the control. These results suggested that transport induced the release of plasma CORT and glycopenia, which affected the contractive status of muscle fibers by changing their area and density, and enhanced glycolysis and even lipolysis. A long-term recovery after transport was beneficial in lowering plasma CORT levels and reducing muscle glycolysis, which might improve broiler meat quality.
Microglia are the main effectors in the inflammatory process of the central nervous system. As the first line of defense, microglia play an important role in the inflammatory reaction. When there is pathogen invasion or cell debris, microglia will be activated rapidly and remove it, while releasing the inflammatory cytokines to mediate inflammatory reaction. Activated microglia were found surrounding lesions of various neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, muscular amyotrophic lateral sclerosis, and multiple sclerosis. Microglia, the effectors of neuronal degeneration and necrosis, are involved in the removal of necrotic neurons. But over activated microglia may accelerate the process of some neurodegenerative diseases. Activated microglia can release cytotoxic factor and cytokines. Some of them may cause further damage to neuron, and some of them can regulate inflammatory cells to gather to the lesion. Microglia-mediated inflammation was considered to be the possible mechanism for the occurrence or deterioration of neurodegenerative diseases. Therefore, inhibiting the activity of microglia appropriately may be an effective way for the treatment of neurodegenerative diseases.
RNAi-based genetically engineered (GE) crops for the management of insect pests are likely to be commercialized by the end of this decade. Without a workable framework for conducting the ecological risk assessment (ERA) and a standardized ERA protocol, however, the utility of RNAi transgenic crops in pest management remains uncertain. The overall goal of this study is to assess the risks of RNAi-based GE crops on a non-target soil micro-arthropod, Sinella curviseta, which could be exposed to plant-protected dsRNAs deposited in crop residues. Based on the preliminary research, we hypothesized that insecticidal dsRNAs targeting at the western corn rootworm, Diabrotica virgifera virgifera, a billion-dollar insect pest, has no adverse impacts on S. curviseta, a soil decomposer. Following a tiered approach, we tested this risk hypothesis using a well-designed dietary RNAi toxicity assay. To create the worst-case scenario, the full-length cDNA of v-ATPase subunit A from S. curviseta were cloned and a 400 bp fragment representing the highest sequence similarity between target pest and non-target arthropods was selected as the template to synthesize insecticidal dsRNAs. Specifically, 10-days-old S. curviseta larvae were subjected to artificial diets containing v-ATPase A dsRNAs from both D. v. virgifera (dsDVV) and S. curviseta (dsSC), respectively, a dsRNA control, β-glucuronidase, from plant (dsGUS), and a vehicle control, H2O. The endpoint measurements included gene expression profiles, survival, and life history traits, such as developmental time, fecundity, hatching rate, and body length. Although, S. curviseta larvae developed significantly faster under the treatments of dsDVV and dsSC than the vehicle control, the combined results from both temporal RNAi effect study and dietary RNAi toxicity assay support the risk hypothesis, suggesting that the impacts of ingested arthropod-active dsRNAs on this representative soil decomposer are negligible.
This study was designed to determine the effect of electrical stunning variables (low currents and high frequencies) on meat quality, glycolytic potential, and blood parameters in broilers. A total of 54 broilers were stunned with 9 electrical stunning methods for 18 s using sinusoidal alternating currents combining 3 current levels (35 V, 47 mA; 50 V, 67 mA; and 65 V, 86 mA) with 3 frequencies (160, 400, and 1,000 Hz). Samples for meat quality were obtained from the pectoralis major (PM) and musculus iliofibularis (MI), and samples for glycogen metabolism were taken from the PM and tibialis anterior muscle at 45 min postmortem. The use of high frequency reduced the shear value in PM (400 and 1,000 Hz vs. 160 Hz; P < 0.01) and cooking loss in MI (1,000 Hz vs. 160 and 400 Hz; P < 0.01). The shear value of PM decreased at high frequency (400 and 1,000 Hz) when current was high (50 V, 67 mA and 65 V, 86 mA; P < 0.01) but increased at high frequency (1,000 Hz) when current was low (35 V, 47 mA). Stunning with 1,000 Hz (vs. 160 Hz) caused low glycogen and glycolytic potential in PM (P < 0.05). Plasma corticosterone decreased (P < 0.05) at high currents (≥50 V, 67 mA) but was not affected by changes in frequency. Electrical current interacted with frequency in plasma glucose, redness 24 h postmortem, shear value (PM), pH 24 h postmortem (MI), and glycolytic potential (tibialis anterior; P < 0.05). This study indicated that high stunning frequencies (400 and 1,000 Hz) may improve meat quality without aggregating stress when the current was not too low (>50 V, 67 mA).
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