Rate of decline in hatchability with preincubation storage of chicken eggs depends on genetic strain

1. The effect of preincubation storage of chicken eggs on hatchability was studied in an Australorp subline (ASS) that had shown a steady decrease of hatchability compared with the original selection line (AS) since its derivation 10 generations ago. The AS line was also included in the study.

2. Eggs were collected over 21 d and the collected eggs were stored at 10° to 12°C and relative humidity of 70 to 80% until they were set together on d 21. Fertility and hatchability of fertile eggs were calculated for each d of collection to study their relationships with age of eggs (length of storage).

3. The hatchability of fertile eggs was considerably different between the two lines in the average over 21 d and, more importantly, in the pattern of decline with length of storage.

4. In the first 3 to 4 d of storage, hatchability was very similar between the lines. However, it decreased linearly at a rate of 1.9% per day of storage over the 21‐d period in the ASS line (average 65.9%), whereas in the AS line (average 78.6%), it stayed at around 84% up to 12 d of storage, when it started to decline at a similar rate as in the ASS line.

5. Fertility was 2.6% higher in the AS line than in the ASS line, but in each line showed no significant trend with age of eggs.     

Isothermal crystallization behavior of PAR/PBT composite prepared by island-in-a-sea fiber method

The PAR fiber reinforced PBT composite was manufactured using the PAR/PBT island-in-a-sea fiber. The isothermal crystallization kinetics of the PAR/PBT composite and the neat PBT resin were investigated in the temperature range of 187–199 °C. To calculate the Avrami parameters for analyzing the crystallization behavior, crystallization peaks were measured and analyzed in terms of the crystallization temperature and the inclusion of the PAR fiber. The crystallization rate of the PBT is faster than that of the PAR/PBT composite from the analysis of their relative crystallinity. Consequently, it is considered that the PAR fiber interrupted the crystal nucleation and growth of the PBT matrix. It can be confirmed with the crystallization half time and the crystalline morphologies at the chosen isothermal temperatures.     

Preliminary Study of the Dietary α‐Tocopherol Requirement in Sea Cucumber,Apostichopus japonicus

This study was conducted to evaluate the dietary α‐tocopherol (vitamin E) requirement in juvenile sea cucumber, Apostichopus japonicus. Sea cucumbers averaging 1.48 ± 0.07 g (mean ± SD) were randomly distributed into 18 rectangular plastic tanks of 20 L capacity in a recirculating system (20 animals per tank). Six semi‐purified experimental diets with average protein and crude lipid levels (dry matter) of 29.7 ± 0.36% and 4.39 ± 0.23% (mean ± SD), respectively were formulated to contain 0 (E4), 15 (E12), 30 (E23), 60 (E44), 120 (E77) and 600 (E378) mg α‐tocopherol/kg diet, supplied as dl‐α‐tocopheryl acetate. Diets were analyzed for α‐tocopherol content by HPLC and the α‐tocopherol levels were 4.01, 12.4, 23.1, 44.3, 77.4 and 378 mg α‐tocopherol/kg diet for E4, E12, E23, E44, E77 and E378 diets, respectively. Casein and defatted fish meal were used as the protein sources in the diets while wheat flour was the carbohydrate source. Sea cucumbers were fed each of the six experimental diets in triplicate groups. At the end of the 14‐week feeding trial, weight gain (WG), specific growth rate (SGR) and feed efficiency (FE) of sea cucumbers fed on E23, E44, E77 and E378 diets were significantly (P < 0.05) higher than those of animals fed on E4 and E12 diets. However, there were no significant differences in WG, SGR and FE among sea cucumbers fed on E23, E44, E77 and E378 diets or among those fed on E4 and E12 diets. Survival of sea cucumbers fed on E44, E77 and E378 diets were significantly higher than those of animals fed on E4, E12 and E23 diets. However, there were no significant differences among sea cucumbers fed on E4, E12 and E23 diets or among those fed on E44 and E77 diets. Whole‐body vitamin E concentration increased with α‐tocopherol content of the diets. Broken line analysis of WG showed an optimum dietary α‐tocopherol requirement of 41 mg α‐tocopherol/kg diet in sea cucumber. These results indicated that the optimum dietary α‐tocopherol requirement in sea cucumber in the form of dl‐α‐tocopheryl acetate could be higher than 23.1 mg α‐tocopherol/kg diet but lower than 44 mg α‐tocopherol/kg diet.     

Development of a microtiter plate ELISA and a dipstick ELISA for the determination of the organophosphorus insecticide fenthion

In previous studies, polyclonal antibodies against the organophosphorus insecticide fenthion were obtained and an indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed for this pesticide. In this study, using these antibodies and an enzyme tracer, direct competitive ELISAs for fenthion in microtiter plate and dipstick formats were developed. The microtiter plate ELISA showed an IC(50) value of 1.2 microg/L with a detection limit of 0.1 microg/L. The antibodies showed negligible cross-reactivity with other organophosphorus pesticides. The use of the dipstick format using Immunodyne as a support membrane allowed the quick visual detection of fenthion in concentrations >10 microg/L. The IC(50) value of the dipstick format using reflectance detection was 15 microg/L with a detection limit of 0.5 microg/L. The recoveries of fenthion from spiked vegetable samples using the two formats without any prior enrichment or cleanup steps were 87-116%.     

Effect of δ-aminolevulinic acid on growth performance, nutrient digestibility, blood parameters and the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide

This study investigated the effects of dietary δ-aminolevulinic acid (ALA) on growth performance, nutrient digestibility, blood parameters and whether ALA improved the immune response of weanling pigs challenged with Escherichia coli lipopolysaccharide (LPS). Eighty pigs (body weight = 7.21 ± 0.51 kg) were allotted to four dietary treatments, with four pens per treatment and five pigs per pen. Basal diets were supplemented with 0, 5, 10, and 15 mg/kg ALA (as-fed basis) and fed for 35 days. At the end of the feeding period, 10 pigs were selected from both the 0- and 10-mg/kg ALA treatment groups; five were injected i.p. with LPS (50 μg/kg BW) and the other five pigs with an equivalent amount of sterile saline, resulting a 2 × 2 factorial arrangement. Blood sample and rectal temperature data were collected at 0, 2, 4 and 12 h after challenge. Growth performance was not affected by dietary treatments over the total experimental period. However, dry matter (DM) and nitrogen (N) digestibility was improved in the 15-mg/kg ALA treatment group at day 35 (P < 0.05). Serum hemoglobin (Hb) and iron levels were also increased, with the 10-mg/kg ALA treatment showing the highest concentration (P < 0.05). On day 35, red (RBC) and white blood cell (WBC) counts were elevated, with the 5- and 10-mg/kg ALA treatments having the highest counts (P < 0.05). During challenge, LPS injection elevated rectal temperature at 2 and 4 h postchallenge (P < 0.05). Plasma cortisol concentration was also increased by LPS injection at 2 and 4 h postchallenge and an ALA-alleviating effect was evident at 2 h postchallenge (P < 0.01). Concentration of plasma insulin-like growth factor-I (IGF-I) was increased in the ALA-supplemented treatments at 2 h postchallenge (P < 0.05). LPS injection increased plasma tumor necrosis factor-α (TNF-α) concentrations at 2, 4 and 12 h (P < 0.01), while an ALA-alleviating effect was observed at 2 and 4 h postchallenge (P < 0.05 and P < 0.10, respectively). Challenge with LPS decreased WBC counts at 2 and 4 h postchallenge (P < 0.01). At 12 h postchallenge, RBC, WBC and lymphocyte counts were affected by LPS challenge, while an ALA effect was only observed on WBC count (P < 0.05). In conclusion, dietary supplementation of ALA in weanling pigs can improve DM and N digestibilities, and iron status and have a beneficial effect on the immune response during inflammatory challenge.     

Biological characteristics of Chinese hamster ovary cells transfected with bovine Prnp

A normal prion protein (PrP^c) is converted to a protease-resistant isoform by an apparent self-propagating activity in transmissible spongiform encephalopathy, a neurodegenerative disease. The cDNA encoding open reading frame (ORF) of the bovine prion protein gene (Prnp) was cloned from Korean cattle by PCR, and was transfected into Chinese hamster ovary (CHO-K1) cells using lipofectamine. The gene expression of the cloned cDNA was confirmed by RT-PCR and Western blotting with the monoclonal antibody, 6H4. Cellular changes in the transfected CHO-K1 cells were investigated using parameters such as MTT, lactate dehydrogenase (LDH), and superoxide dismutase (SOD) activities, as well as nitric oxide (NO) production, and an apoptosis assay. In the MTT and LDH assays, the bovine PrnP-transfectant showed a lower proliferation rate than the wild-type (p < 0.05). Production of NO, after LPS or ConA stimulation, was not detected in either transfectants or CHO-K1 cells. In SOD assay under ConA stimulation, the SOD activity of transfectants was 10 times higher than that of CHO-K1 cells at 6 h after treatment (p < 0.05). The genomic DNA of both the transfectants and control cells began to be fragmented at 6 h after treatment with cyclohexamide. Caspase-3 activity was reduced by transfection with the bovine Prnp (p < 0.05). Conclusively, the viability of transfectants expressing exogenous bovine Prnp was decreased while the capacities for cellular protection against antioxidative stress and apoptosis were increased.     

Endocarditis associated with Escherichia coli in a sea lion (Zalophus californianus).

Endocarditis associated with Escherichia coli was diagnosed in a 2-year-old male California sea lion (Zalophus californianus). The diagnosis was based on light microscopic examination and bacterial isolation from the valvular lesion. This is the first case of bacterial endocarditis reported in a sea lion.     

Comparison of regional climate scenario data by a spatial resolution for the impact assessment of the uncertainty associated with meteorological inputs data on crop yield simulations in Korea

Uncertainty of crop yield simulation would be affected by weather input data prepared from different sources of climate datasets. Although regional climate data at a high spatial resolution would be useful for the impact assessment of climate change on crop production, little effort has been made to characterize the uncertainty associated with such climate data in terms of crop yield simulations. The objectives of this study were to compare climate scenario data products obtained from a series of downscaling processes and to identify an overall pattern of uncertainty in these climate data in terms of crop yield simulation. Regional climate scenario data from 2011 to 2014 had a spatiotemporal pattern of uncertainty, which differed by meteorological variables and spatial resolution. Overall, the uncertainty of daily minimum temperature was greater than that of maximum temperature. Daily minimum temperature also had relatively greater uncertainty in an early season of crop production, which could result in the cumulative impact on the uncertainty of crop yield simulations. For the uncertainty of climate data at different spatial resolution, climate data at higher spatial resolution, e.g. 1 km, tended to have lower uncertainty than data at resolution of 12.5 km did. Still, the uncertainty of regional climate data was relatively similar between data at resolution of 12.5 km and 1 km in major rice production areas in Korea except in areas near Seosan. This merits further studies to examine actual differences in projected crop yields using regional climate scenario data in the future and to assess the impact of uncertainty associated with regional climate data on crop yield simulation.