Effect of Maternal Age on the Ratio of Cleavage and Mitochondrial DNA Copy Number in Early Developmental Stage Bovine Embryos

Age-associated deterioration in both the quality and quantity of mitochondria occurs in older women. The main aim of this study was to examine the effect of age on mitochondrial DNA copy number (mtDNA number) in early developmental stage bovine embryos as well as the dynamics of mtDNA number during early embryo development. Real-time PCR was used to determine mtDNA number. In vitro-produced embryos 48 h after insemination derived from Japanese black cows, ranging in age from 25 to 209 months were categorized based on their cleavage status. There was an overall negative relationship between the age of the cow and cleavage status, to the extent that the ratio of embryos cleaved over the 4-cell stage was greater in younger cows. The mtDNA number did not differ among the cleaved status of embryos. In the next experiment, oocytes collected from each donor cow were divided into 2 groups containing 10 oocytes each, in order to compare the mtDNA number of mature oocytes and early developmental stage embryos within individuals. Upon comparing the mtDNA number between oocytes at the M2 stage and early developmental stage 48 h post insemination, mtDNA number was found to decrease in most cows, but was found to increase in some cows. In conclusion, age affects the cleaving ability of oocytes, and very old cows (> 180 months) tend to have lower mtDNA numbers in their oocytes. The change in mtDNA number during early development varied among individual cows, although overall, it showed a tendency to decrease.     

Gastrointestinal motility modulation by stress is associated with reduced smooth muscle contraction through specific transient receptor potential channel

Excessive stress response causes disability in social life. There are many diseases caused by stress, such as gastrointestinal motility disorders, depression, eating disorders, and cardiovascular diseases. Transient receptor potential (TRP) channels underlie non-selective cation currents and are downstream effectors of G protein-coupled receptors. Ca²⁺ influx is important for smooth muscle contraction, which is responsible for gastrointestinal motility. Little is known about the possible involvement of TRP channels in the gastrointestinal motility disorders due to stress. The purpose of this study was to measure the changes in gastrointestinal motility caused by stress and to elucidate the mechanism of these changes. The stress model used the water immersion restraint stress. Gastrointestinal motility, especially the ileum, was recorded responses to electric field stimulation (EFS) by isometric transducer. EFS-induced contraction was significantly reduced in the ileum of stressed mouse. Even under the conditions treated with atropine, EFS-induced contraction was significantly reduced in the ileum of stressed mouse. In addition, carbachol-induced, neurokinin A-induced, and substance P-induced contractions were all significantly reduced in the ileum of stressed mouse. Furthermore, the expression of TRPC3 was decreased in the ileum of stressed mouse. These results suggest that the gastrointestinal motility disorders due to stress is associated with specific non-selective cation channel.     

Energy expenditure for chewing in sheep fed timothy or sudangrass hay at the same intake level

In order to investigate the energy expended in chewing during eating and rumination in sheep fed timothy or sudangrass hay at the same intake level, the energy expenditure of the head was measured using the arterial-venous difference technique and that of the whole body was measured using an open-circuit, indirect respiration calorimeter. There was no difference in the per-chew energy expenditure between timothy hay and sudangrass hay during eating and rumination, but for both types of hay there was a difference in energy expenditure between eating (0.25 J per chew per kilogram body weight) and rumination (0.18 J per chew per kilogram body weight). There was no effect of time period after feeding on the energy expended in one chew during eating and rumination. On average, for a given type of hay, the energy expended in chewing during eating + rumination accounted for 4.9% of the daily energy expenditure of the whole body.     

Extensive study on forest runoff water chemistry over east Asia

The chemistry of runoff waters from 13 forested watersheds in six regions (four regions from Japan, one from southern China and one from northern Thailand) was evaluated. The Cl⁻ concentrations in runoff waters were higher in those watersheds which had closed canopies and were nearer to the ocean. The NO₃ ⁻ concentrations were higher in those watersheds having the developed soils and high moisture conditions, but were lower in tropical and subtropical regions for those watersheds which had high rates of nitrogen uptake and for watersheds with large areas of saturated soils. The SO₄ ²⁻ concentrations were affected by SO₄ ²⁻ adsorption properties of the soils: at Shibecha, Jiulianshan, and Chiang Mai with high adsorption capacities SO₄ ²⁻ concentrations in streams were low. High SO₄ ²⁻ concentrations were found at Mt. Hiei and Kagawa due to the weathering of sulfur minerals and high levels of atmospheric sulfur deposition. Within regions SO₄ ²⁻ concentrations were inversely related to NO₃ ⁻ concentrations. A comparison among the watersheds suggested H⁺ consumption in deeper soil that increased pH and HCO₃ ⁻ concentrations of the runoff waters of some watersheds. Anion concentrations increased with low H.I. (Humidity Index) values suggesting that dry conditions increased concentrations due to high rates of evapotranspiration.     

Reduced sensitivity to fenarimol in Japanese field strains of Venturia nashicola

Monoconidial strains of Venturia nashicola Tanaka et Yamamoto were isolated from Japanese or Chinese white pear trees which had never been treated with sterol demethylation inhibitors (DMIs) and their baseline sensitivities to fenarimol were determined by mycelial growth tests on fungicide-amended culture media. Strains were also obtained from Japanese pear orchards, which had been intensively treated with DMIs for several years and monitored for the shifts of fenarimol sensitivity in comparison with the baseline sensitivity. Results suggested slight shifts to lower fenarimol sensitivity in strains isolated from DMI-treated Japanese pear orchards. However, in inoculation tests on pear seedlings, fenarimol still provided adequate control of V. nashicola strains with reduced sensitivity to fenarimol in vitro, suggesting that the performance of this fungicide will still be maintained in the field. © 1998 Society of Chemical Industry     

Effects of GH gene polymorphism and sex on carcass traits and fatty acid compositions in Japanese Black cattle

To investigate the effects of bovine growth hormone (bGH) gene polymorphism on carcass traits and fatty acid compositions in Japanese Black cattle caused by nucleotide substitution of CTG (allele A)/GTG (allele B) at codon 127 and of ACG (allele A and B)/ATG (allele C) at codon 172 of bGH, GH genotypes of 135 cattle were determined using allele specific-multiplex polymerase chain reaction (PCR). Allele A gave greater rib thickness and lower melting point of fat (MP) while allele B gave higher C18:1% ( P  < 0.05). Allele C gave higher C18:1, monounsaturated fatty acid (MUFA), unsaturated fatty acid (USFA) percentages ( P  < 0.05). It also gave lower saturated fatty acid (SFA) percentages, higher MUFA/SFA and USFA/SFA ratios, and lower MP ( P  < 0.05). Interactions of sex and GH alleles were analyzed. In heifers, allele A gave higher carcass weight, daily carcass gain, rib eye area, rib thickness, subcutaneous fat thickness, and BMS while allele B gave greater rib eye area and rib thickness ( P  < 0.05). Allele C gave higher C18:1 ( P  < 0.01), MUFA ( P  < 0.01), USFA percentages ( P  < 0.05) and MUFA/SFA and USFA/SFA ratios ( P  < 0.01), and lower C16:0 and SFA percentages ( P  < 0.05) and MP ( P  < 0.01). GH gene polymorphism affected carcass traits and fatty acid compositions although the effects were more pronounced in heifers.     

Milking performance evaluation and factors affecting milking claw vacuum levels with flow simulator

Milking performance of milking machines that matches the production capability of dairy cows is important in reducing the risk of mastitis, particularly in high‐producing cows. This study used a simulated milking device to examine the milking performance of the milking system of 73 dairy farms and to analyze the factors affecting claw vacuum. Mean claw vacuum and range of fluctuation of claw vacuum (claw vacuum range) were measured at three different flow rates: 5.7, 7.6 and 8.7 kg/min. At the highest flow rate, only 16 farms (21.9%) met both standards of mean claw vacuum ≥35 kPa and claw vacuum range ≤ 7 kPa, showing that milking systems currently have poor milking performance. The factors affecting mean claw vacuum were claw type, milk‐meter and vacuum shut‐off device; the factor affecting claw vacuum range was claw type. Examination of the milking performance of the milking system using a simulated milking device allows an examination of the performance that can cope with high producing cows, indicating the possibility of reducing the risk of mastitis caused by inappropriate claw vacuum.