Mdivi-1, mitochondrial fission inhibitor,impairs developmental competence and mitochondrial function of embryos and cells in pigs

Mitochondria are highly dynamic organelles that undergo constant fusion/fission as well as activities orchestrated by large dynamin-related GTPases. These dynamic mitochondrial processes influence mitochondrial morphology, size and function. Therefore, this study was conducted to evaluate the effects of mitochondrial fission inhibitor, mdivi-1, on developmental competence and mitochondrial function of porcine embryos and primary cells. Presumptive porcine embryos were cultured in PZM-3 medium supplemented with mdivi-1 (0, 10 and 50 μM) for 6 days. Porcine fibroblast cells were cultured in growth medium with mdivi-1 (0 and 50 μM) for 2 days. Our results showed that the rate of blastocyst production and cell growth in the mdivi-1 (50 μM) treated group was lower than that of the control group (P < 0.05). Moreover, loss of mitochondrial membrane potential in the mdivi-1 (50 μM) treated group was increased relative to the control group (P < 0.05). Subsequent evaluation revealed that the intracellular levels of reactive oxygen species (ROS) and the apoptotic index were increased by mdivi-1 (50 μM) treatment (P < 0.05). Finally, the expression of mitochondrial fission-related protein (Drp 1) was lower in the embryos and cells in the mdivi-1-treated group than the control group. Taken together, these results indicate that mdivi-1 treatment may inhibit developmental competence and mitochondrial function in porcine embryos and primary cells.     

Contrast enhanced ultrasonography of kidney in conscious and anesthetized beagle dogs

Contrast enhanced ultrasound (CEUS) is useful to evaluate tissue perfusion in the kidney. In veterinary medicine, sedation or anesthesia may be required in uncooperative or panting patients. The aim of this study was to evaluate and compare the normal kidney perfusion patterns in conscious and anesthetized dogs using CEUS. Eight healthy beagles were used in this study. Scanning was performed in conscious dogs using manual restraint (conscious group), or under general anesthesia using tiletamine-zolazepam and medetomidine (TZM group) or medetomidine (M group). The contrast agent (Sonovue^®) was administered as an IV bolus. The peak intensity (PI), time to peak enhancement from injection (TTP₀) and the time to peak enhancement from the initial rise (TTP_up), upslope, downslope and area under the curve (AUC) were analyzed. Compared to the cortical values in the conscious group, TTP₀ was significantly delayed in the TZM group, and upslope, TTP₀ and TTP_up were significantly different in the M group. The AUCs in the TZM and M groups were not different from those in the conscious group. The upslope of renal medullary perfusion was significantly decreased in the TZM and M groups. TTP₀ and TTP_up were also significantly delayed in these groups. The AUC of the medulla was significantly decreased in the M group. Therefore, TZM is useful as an anesthetic protocol when performing CEUS, and the obtained data may serve as reference values in the evaluation of renal perfusion using CEUS in dogs under anesthesia.     

抗生素FR-008基因簇上游区域的DNA序列分析

链霉菌FR-008产生一种七烯大环内酯类抗生素FR-008，对真菌具有很高的抗菌活性，并对蚊子幼虫有高毒性（袁德军和周启，1990）。负责合成FR-008的基因簇被定位（Hu et al．，1994），有21个基因（共138kb，GenBank accession number AY310323）被确认参与了抗生素FR-008的生物合成以及调节和外运（Chen et al．，2003）。然而，在FR-008基因簇最左端fscO基因上游的基因是否与FR-008抗生素生物合成相关？为此，本研究对FR-008基因簇上游区域进行了序列测定和分析。     

Efficacy of probiotics from anaerobic microflora with prebiotics on growth performance and noxious gas emission in growing pigs

We investigated the effect of probiotics from anaerobic microflora with prebiotics (synbiotics) on growth performance, noxious gas emission and fecal pathogenic bacteria populations in growing pigs. The basal diet, which contained approximately 25% corn, 24% whey, 12% wheat and 12% soybean meal, was supplemented alternatively with 0.15% antibiotics (US diet), prebiotics and 0.2% probiotics from anaerobic bacteria (BS diet), yeast (YS diet), mold (MS diet) or compounds (CS diet). One hundred and fifty pigs were fed an experimental diet for 15 days. Although the growth performance was not affected by supplemental synbiotics, the BS group showed higher dry matter and crude protein digestibility. The BS group decreased fecal ammonia and amine gas emissions, and increased fecal acetate gas emission compared with the US group. All synbiotics groups decreased in fecal propionate gas emission. Fecal Escherichia coli population was lower in the synbiotics groups than in the US group. Therefore, the results of the present study suggest that synbiotics exert similar effects with antibiotics on the nutrient digestibility and fecal microflora composition in growing pigs. Moreover, synbiotics can also decrease the fecal noxious gas emission in growing pigs.     

Soil texture affects the conversion factor of electrical conductivity from 1:5 soil-water to saturated paste extracts

Electrical conductivity (EC) of soil-water extracts is commonly used to assess soil salinity. However, its conversion to the EC of saturated soil paste extracts (EC_e), the standard measure of soil salinity, is currently required for practical applications. Although many regression models can be used to obtain EC_e from the EC of soil-water extracts, the application of a site-specific model to different sites is not straightforward due to confounding soil factors such as soil texture. This study was conducted to develop a universal regression model to estimate a conversion factor (CF) for predicting EC_e from EC of soil-water extracts at a 1:5 ratio (EC_1:5), by employing a site-specific soil texture (i.e., sand content). A regression model, CF=8.910 5e^{0.010 6sand}/1.298 4 (r²=0.97, P < 0.001), was developed based on the results of coastal saline soil surveys (n=173) and laboratory experiments using artificial saline soils with different textures (n=6, sand content=10%-65%) and salinity levels (n=7, salinity=1-24 dS m^-1). Model performance was validated using an independent dataset and demonstrated that EC_e prediction using the developed model is more suitable for highly saline soils than for low saline soils. The feasibility of the regression model should be tested at other sites. Other soil factors affecting EC conversion factor also need to be explored to revise and improve the model through further studies.     

Evaluation of left ventricular function with cardiac magnetic resonance imaging and echocardiography after administration of dobutamine and esmolol in healthy beagle dogs

Unlike echocardiography, cardiac magnetic resonance imaging (cardiac MRI) results in a near-exact assessment of cardiac structures and function. However, most veterinary studies have focused on dogs with normal cardiac function. We hypothesized that there would be significant differences in cardiac measurements between cardiac MRI and echocardiography when left ventricular (LV) function was abnormal. This study was undertaken to compare measurements of LV function produced by cardiac MRI and echocardiography in dogs whose LV function was altered by pharmacological agents. This study was conducted with six healthy beagle dogs. We increased left ventricular contractility by administration of dobutamine; we decreased cardiac contractility with esmolol. Stroke volume measurements were made by using both cardiac MRI and echocardiography under seven different conditions with general anesthesia: control, three doses of esmolol (100, 200, and 500 µg/kg/min), and three doses of dobutamine (10, 20, and 50 µg/kg/min). Experiments involving each condition were conducted at least 1 week apart. When LV contractility was normal, ejection fraction (EF) and stroke volume (SV), as measured by echocardiography and cardiac MRI, were not significantly different. However, when contractility was changed by pharmacological agents, EF and SV were overestimated by echocardiography, compared to MRI. Evaluation of cardiac function in patients treated with pharmacological agents should be conducted carefully because EF and SV measured by echocardiography can be overestimated, compared with EF and SV obtained by cardiac MRI.     

Influence of feeding regime on fatty acid composition in young red-spotted grouper Epinephelus akaara

ABSTRACT:   Young red-spotted grouper Epinephelus akaara with an average total length of 3.4 cm were divided into five groups in floating net-cages, and reared under satiated conditions with different feeding frequencies (0.5, 1, 2, 4 and 8 times per day) for 40 days. Total food intake increased with feeding frequency. Feeding four times per day resulted in the highest growth and food conversion efficiency. Total lipid accumulation in the muscle, liver and intraperitoneal fat body (IPF) increased with feeding frequency. Red-spotted grouper were found to contain a high proportion of docosahexaenoic acid (DHA) in the muscle. Fish fed 0.5 times per day were characterized as having a high proportion of DHA in triglycerides (TG) in muscle (80%), liver (69%) and IPF (18%). Increasing saturated fatty acids and a relative reduction of DHA were observed in the muscle TG as the feeding frequency increased. Frequent feeding accelerated the accumulation of eicosapentaenoic acid and saturated acids in the liver and IPF. Low saturated acids and a subsidiary proportional increase in DHA were the result of the low lipid reserves. A possible role for DHA and saturated acids are discussed with regard to lipid reserves.