Development of a Multi-Resolution Emission Inventory and Its Impact on Sulfur Distribution for Northeast Asia

Emissions in East Asia for 1993 by administrative units and source types are estimated to support regional emission assessments and transport modeling studies. Total emission of SO_x, NO_x, soil NO_x, N₂O, and NH₃ are 24 150, 12 610, 1963, 908, and 8263 kton yr^-1, respectively.China's emission contribution is the highest for every species.The area sources are the most significant source type for SO_x and NO_x, but the fraction due to mobile source is highest for NO_x. Major LPSs are located from the middle to the east part of China, south and middle-west part of South Korea, and the east part of Japan. The area sources of SO_x show a pattern similar to population density, whereas NH₃ shows a strong landuse dependency. Detail emissions analysis reveals higher SO_x emission `cores' within each province. The estimated emissions are used to estimate sulfur deposition in the regions. The seasonal average sulfur distribution amounts are estimated from the ATMOS2 chemical transport model. The results showed anti-correlation with temperature for sulfur (SO₂ + SO₄ ^-2) concentrations and a positive correlation with rainfall for deposition.     

Skeletal unit construction of rat mandible based on the masticatory muscle anatomy and double microcomputed tomography

This study aimed to divide the mandible into skeletal units based on three‐dimensional (3D) muscular anatomy with microcomputed tomography (micro‐CT) of Sprague–Dawley rat. Five normal rats were micro‐CT scanned at 12 weeks of age before and after contrast enhancements for the masticatory muscles. Three‐dimensional reconstruction of the mandible was performed from the initial micro‐CT images, followed by segmentation of the masticatory muscles using the second enhanced micro‐CT data. Bone and muscle models were superimposed based on the teeth and bony structures to evaluate muscular orientation and attachment. The mandible was divided into skeletal units using the bony structures and muscle attachments. The mandibular foramen and mental foramen were adopted as the reference points based on their anatomical and developmental significance. The skeletal units consisted of the condylar, coronoid, angular, body and symphyseal units. Further evaluation of these units in relation to development, growth, and other biology and medicine will be helpful in elucidating their biological identities.     

Parameter estimates for genetic effects on carcass traits of Korean native cattle

Data (n = 1,746) collected from 1985 through 1995 on Korean Native Cattle by the National Livestock Research Institute of Korea were used to estimate genetic parameters for marbling score, dressing percentage, and longissimus muscle area, with backfat thickness, slaughter age, or slaughter weight as covariates. Estimates were obtained with REML. Model 1 included animal genetic and residual random effects. Model 2 was extended to include an uncorrelated random effect of the dam. Model 3 was based on Model 1 but also included sire x region x year-season interaction effects. Model 4 combined Models 2 and 3. All models included fixed effects for region x year-season and age of dam x sex combinations. From single-trait analyses, estimates of heritability with covariates to adjust for backfat thickness, slaughter age, and slaughter weight from Model 4 were, respectively, .10, .08, and .01 for marbling score; .09, .12, and .16 for dressing percentage; and .18, .17, and .24 for longissimus muscle area. From three-trait analyses, estimates of genetic correlations between marbling score and dressing percentage, marbling score and longissimus muscle area, and dressing percentage and longissimus muscle area were, respectively, -.99, .20, and -.11 with backfat thickness as covariate; -.88, .47, and .01 with slaughter age as covariate; and -.03, .39, and .91 with slaughter weight as covariate. Results of this study suggest that choice of covariate (backfat thickness, slaughter age, or slaughter weight) for the model seems to be important for carcass traits for Korean Native Cattle. Including sire x region x year-season interaction effects in the model for marbling score and dressing percentage may be important because whether sire x region x year-season interaction effects were in the model affected estimates of other variance components for the three carcass traits. Whether the maternal effect was in the model had little effect on estimates of other parameters. With backfat thickness and slaughter age end points, selection for increasing marbling score would be expected to result in decreasing dressing percentage for Korean Native Cattle. With slaughter weight as a covariate for end point, increased longissimus muscle area would be associated with increased dressing percentage, and increased marbling score would be related to increased longissimus muscle area. The differences in estimates associated with choice of end point, however, need further study.     

Colonization strategy of Campylobacter jejuni results in persistent infection of the chicken gut

Although poultry meat is now recognized as the main source of Campylobacter jejuni gastroenteritis, little is known about the strategy used by the bacterium to colonize the chicken intestinal tract. In this study, the mechanism of C. jejuni colonization in chickens was studied using four human and four poultry isolates of C. jejuni. The C. jejuni strains were able to invade chicken primary cecal epithelial crypt cells in a predominantly microtubule-dependent way (five out of eight strains). Invasion of cecal epithelial cells was not accompanied by necrosis or apoptosis in the cell cultures, nor by intestinal inflammation in a cecal loop model. C. jejuni from human origin displayed a similar invasive profile compared to the poultry isolates. Invasiveness of the strains in vitro correlated with the magnitude of spleen colonization in C. jejuni inoculated chicks. The C. jejuni bacteria that invaded the epithelial cells were not able to proliferate intracellularly, but quickly evaded from the cells. In contrast, the C. jejuni strains were capable of replication in chicken intestinal mucus. These findings suggest a novel colonization mechanism by escaping rapid mucosal clearance through short-term epithelial invasion and evasion, combined with fast replication in the mucus.     

Evaluation of sulphur amino acid requirement of male Korean native ducklings from hatch to 21 day of age

1. A dose-response experiment was conducted with male Korean native ducklings (KND) to evaluate the total sulphur amino acid (TSAA) requirement from hatch to 21 d of age.

2. A completely randomised design with 7 dietary TSAA concentrations (0.62%, 0.65%, 0.68%, 0.71%, 0.74%, 0.77% and 0.80%) were used with 6 replications per treatment.

3. Body weight (BW) and feed intake were measured weekly to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed conversion ratio (FCR). One duckling per pen (n = 6) was killed by cervical dislocation to weigh empty body and drumsticks at the conclusion of experiment.

4. BW was improved significantly with increasing TSAA content, in a non-linear manner. A significant decrease of FCR was shown with increasing TSAA contents. TSAA requirement was determined by taking a mean value after fitting the data to both a linear-plateau and a quadratic-plateau model. Estimated TSAA requirements were 0.70%, 0.70%, 0.66% and 0.70% for the maximum BW, ADG and ADFI and for the minimum FCR, respectively. Increasing TSAA content improved quantity of full body weight (FBW), empty body weight (EBW) and drumstick weight (DSW), but there was no effect on proportion of DSW in relation to EBW and proportion of EBW to FBW.

5. In conclusion, the growth of male KND during 1 to 21 d of age was improved with increasing TSAA content, suggesting optimal TSAA requirements estimated by two analysis models.     

Presence of chlorogenic acid during in vitro maturation protects porcine oocytes from the negative effects of heat stress

Chlorogenic acid (CGA) is known to protect oocytes from oxidative stress. Here we investigated the effects of CGA on porcine oocyte maturation under heat stress and subsequent embryonic development after parthenogenetic activation. For in vitro maturation (IVM) at 41.0°C (hyperthermic condition), supplementation of the maturation medium with 50 μM CGA significantly improved the percentage of matured oocytes and reduced the rate of apoptosis relative to oocytes matured without CGA (p < .05). CGA treatment of oocytes during IVM under hyperthermia tended to increase (p < .1) percentage of blastocyst formation after parthenogenesis and significantly increased (p < .05) the total cell number per blastocyst relative to oocytes matured without CGA. For IVM at 38.5°C (isothermic condition), CGA significantly improved the rate of blastocyst development compared with oocytes matured without CGA (p < .05), but did not affect oocyte maturation, apoptosis rate or the number of cells per embryo. Omission of all antioxidants from the IVM medium significantly reduced the rate of oocyte maturation, but the rate was restored upon addition of CGA. These results demonstrate that CGA is a potent antioxidant that protects porcine oocytes from the negative effects of heat stress, thus reducing the frequency of apoptosis and improving the quality of embryos.     

Long‐term dietary supplementation of organic selenium modulates gene expression profiles in leukocytes of adult pigs

Seventy‐two pigs at 34.4 kg body weight (BW) were allotted to two treatments with six replicates/treatment and six pigs/pen: the CON (negative control, no added selenium (Se)) and the OS (0.36 mg/kg added selenium from selenium‐enriched yeast). Pigs were fed until 130 kg BW. The CON diet contained 0.18 mg/kg indigenous Se whereas the OS diet contained 0.54 mg/kg Se. Blood samples were collected at 130 kg BW and further processed for microarray analysis, prepared with 885 genes related to immune function of pigs. Among those, 28 genes related to improved immune status and innate immunity were up‐regulated (P < 0.05) in leukocytes from Se‐fed pigs and those include major histocompatibility class I (> 1.66), arginase I (> 1.27), integrin beta‐1‐subunit (> 1.20), toll like receptor 2 (> 1.12) and double‐stranded RNA‐dependent protein kinase. However, 24 genes including tissue factor (< 4.70), serum amyloid A‐2 protein (< 3.11) and p27Kip1 (< 1.42) were down‐regulated (P < 0.05) in leukocytes from Se‐fed pigs. Expression of four selected genes was validated using quantitative PCR (qPCR) showing significant correlation between mircroarray analysis and qPCR analysis. This study indicates that a long‐ term dietary supplementation (0.3%) of organic Se improves the expression of genes that are related to enhanced immunity of pigs.     

An improved method for a rapid determination of phytase activity in animal feed

The current direct colorimetric assay for phytase activity in feeds has interference from high P background and other factors. Our objective was to develop a rapid and reliable spin column method to accurately determine phytase activity in feed ingredients or complete diets. After the feed sample was extracted by stirring in 0.2 M citrate buffer, pH 5.5, for 30 min at room temperature, the oily layer of the supernatant fraction was removed by passing through an acrodisc syringe filter (0.45-microm HT Tuffryn membrane, Gelman Laboratory, Ann Arbor, MI). The filtrate was then loaded onto a spin column (MW cutoff 30,000, Millipore, Bedford, MA) to remove free phosphate before the phytase activity assay. Compared with the direct assay, this new procedure improved both accuracy and reproducibility. When diets contained phytase at 0 to 1,500 U/kg (as fed), the CV for multiple assays of the same samples (n = 6) by the new method ranged from 1 to 6% compared with 28 to 39% by the direct method. A linear relationship was found between the added phytase activity in practical diets and the analyzed activity by the new method (r2 = 0.99; P < 0.01). In conclusion, the spin column method is an improved assay for phytase activity in animal feed, and may be used for quality control of phytase supplementation.