Effects of crushed conspecifics on growth and survival of Penaeus monodon Fabricius post larvae

In the present study, the hypothesis tested was that Penaeus monodon post‐larvae (PL) experience lower growth when exposed to crushed conspecifics, which was achieved by exposing individual P. monodon PL with abundant food for 4 weeks to a gradient from 0 to 100 crushed conspecific PL L^?1. Both dry weight (48.5±7.2 mg) and body size (28.0±1.3 mm) of animals exposed to 1 macerated PL L^?1 were significantly (P≤0.011) higher than those of animals in treatments with 0, 5 and 10 crushed PL L^?1 (average over treatments: 25.6±3.2 mg; 23.4±0.5 mm). All animals died within 1 week when exposed to 70 and 100 crushed PL L^?1, and within 3–4 weeks when exposed to 50 and 30 crushed PL L^?1. Exposure time affected mortality and it appeared that LC₅₀ values decreased from 60 to 13 crushed PL L^?1 from 1 to 4 weeks' exposure. Survival of P. monodon PL was negatively correlated to pH, biological oxygen demand, ammonia and nitrate. In conclusion, low dose of crushed conspecifics has a stimulatory effect on P. monodon PL, as larvae were heavier and larger, while high doses cause high mortality.     

Evaluation of the microbiological safety and quality of Vietnamese <Emphasis Type="Italic">Pangasius hypophthalmus</Emphasis> during processing by a microbial assessment scheme in combination with a self-assessment questionnaire

Pangasius hypophthalmus (referred to as Pangasius or tra fish in Vietnam) has become highly appreciated by consumers in the European Union, USA, Japan, etc. and is of worldwide economic importance. Therefore, the microbial quality and safety of Pangasius fish processed for export was assessed by means of a microbial assessment scheme throughout the entire production process. A total of 144 samples were collected from various processing steps and analyzed. It was determined that the microbial safety and quality of the products was not guaranteed as the contamination levels remained high throughout processing. Escherichia coli, Staphylococcus aureus and Vibrio cholerae were present on the hands of food operators, particularly those in the packaging area. Moreover, the presence of Listeria monocytogenes (1 positive out of 9 samples) and V. cholerae (4/9) on the final products was likely a result of inadequate hygiene practices in the processing environment. Also discussed in this paper are the results of a self-assessment questionnaire, which provide insight into the performance of the food safety management system currently implemented at the company. These data are of major importance in order to contribute valuable information to the local and international trade point of view in general and to the intended customers in particular.     

Studies of the digestibility of pigs fed dietary sucrose, fructose or glucose.

Digestion of sucrose, fructose and glucose was studied in pigs with reentrant cannulas in the distal ileum or intact pigs fed diets formulated with sucrose, fructose and glucose as the major energy source and torula yeast. Sucrose and glucose were completely digested in the small intestine (apparent digestibility, 98.3 and 98.3%, respectively but a fraction of the dietary fructose escaped to the large intestine (adjusted value, 11.7%). There was no carbohydrate in rectal contents of the pigs. There was no carbohydrate influence on the pre-caecal or total digestibility of nitrogen.     

SURGICAL MANAGEMENT OF A TRAUMATIC ELBOW LUXATION WITH CIRCUMFERENTIAL SUTURE PROSTHESES IN A RABBIT (ORYCTOLAGUS CUNICULUS)

A 2-year-old dwarf rabbit was referred for right forelimb lameness of 1-week duration. Physical examination and radiographic findings were consistent with an elbow luxation. Manual reduction under anesthesia was unsuccessful in correcting the luxated joint. A surgical approach was recommended to repair the rabbit elbow luxation. Transcondylar, transradial, and transulnar tunnels were drilled from lateral to medial with 2 suture prostheses being placed, 1 from the radius to the humerus and 1 from the humerus to the ulna. Analgesia was provided and the patient was reevaluated on days 2, 7, and 14 after the procedure. The luxation was reduced and no recurrence was noted a year following the surgical procedure. Circumferential suture prostheses, recently described with no reported postoperative complications in cats, can be used successfully in rabbits as evidenced in this case report.     

Where art thou louse? A snapshot of attachment location preferences in salmon lice on Atlantic salmon hosts in sea cages

Problematic sea lice infestations on farmed Atlantic salmon (Salmo salar) have motivated extensive research and development into new methods to prevent, monitor and control sea lice. Most of these technologies require detailed information on the behaviour, spatial distribution and demography of lice on host fish. This study investigated how salmon lice (Lepeophtheirus salmonis) infestation density varies across the host's surface under sea cage farming conditions. Lice abundance, demography and attachment location were tracked over time, with repeated sampling of 300 individually tagged salmon across three replicate experimental sea cages. The data reveal clear differences in attachment locations according to sex and stage, but with an overall preference for the dorsal surface among mobile stages—dorsal head for adult females and dorsal-posterior section for males and pre-adults. Total lice abundance was highly variable between repeated measures of individual fish, consistent with frequent host-switching or mortality. Total lice numbers also declined between sampling dates, likely due to handling, with lost mobile lice being almost exclusively adult males. As the distribution of sea lice on hosts is likely determined by numerous factors, future image-based automated detection systems should be validated in settings that reflect the complex host–parasite interactions that occur in open farming systems.     

Assessment of biochemical and antioxidant diversities in a shallot germplasm collection from Vietnam and its surrounding countries

The shallot is considered an important genetic resource for Allium breeding programs because, compared to the bulb onion, the shallot contains higher levels of several functional chemical compounds. However, there may be differences in content, composition and beneficial activity among shallot landraces. This study was carried out to characterize the differences in phenolic, quercetin, sugar, S-alk(en)yl-l-cystein sulfoxide (ACSO), and saponin contents and antioxidant capacities of a shallot germplasm including 31 strains derived from different regions of Vietnam and six other countries. A wide variation was observed in the quantitative analyses of the chemical contents. Shallots with high contents of polyphenols, saponins, and quercetins were found in the south of Vietnam and other low-latitude countries. Meanwhile, those possessing fairly high ACSO and sugar contents were observed in the north of Vietnam. Qualitative analysis of saponins via thin layer chromatography did not show clear variation among shallot strains, but polymorphism was observed between the shallot and other Allium species, such as A. roylei. The principal component analysis could clearly discriminate shallot strains by their geographical origins. All shallot strains showed potent antioxidant activities in a DPPH assay. The highest antioxidant capacity was in the strains possessing relatively high contents of polyphenol, quercetin, and saponin. Significant correlations were found between antioxidant capacity (IC ₅₀ ^?1 ) and four groups of chemical compounds (polyphenols, quercetins, saponins, and ACSOs) (r = 0.40–0.59). A strong correlation was observed between IC ₅₀ ^?1 and quercetin contents (r = 0.59, p < 0.01). The six Fusarium-inoculated shallot strains seemed to be adequately resistant against disease, and the levels of resistance may be related to the saponin content in the bulb tissues.     

Structure of Fucoidan from Brown Seaweed Turbinaria ornata as Studied by Electrospray Ionization Mass Spectrometry (ESIMS) and Small Angle X-ray Scattering (SAXS) Techniques

The purpose of this study is to elucidate both the chemical and conformational structure of an unfractionated fucoidan extracted from brown seaweed Turbinaria ornata collected at Nha-trang bay, Vietnam. Electrospray ionization mass spectrometry (ESI-MS) was used for determining the chemical structure and small angle X-ray scattering (SAXS) provided conformational of the structure at the molecular level. The results showed that the fucoidan has a sulfate content of 25.6% and is mainly composed of fucose and galactose residues (Fuc:Gal ≈ 3:1). ESIMS analysis suggested that the fucoidan has a backbone of 3-linked α-l-Fucp residues with branches, →4)-Galp(1→ at C-4 of the fucan chain. Sulfate groups are attached mostly at C-2 and sometimes at C-4 of both fucose and galactose residues. A molecular model of the fucoidan was built based on obtained chemical structure and scattering curves estimated from molecular model and observed SAXS measurement were fitted. The results indicated that fucoidan under study has a rod-like bulky chain conformation.     

Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.     

The sensitivity and specificity of two methods for detecting Fasciola infections in cattle.

Counts of Fasciola spp. eggs in faeces and measurements of antibody concentration to the excretory/secretory antigens of Fasciola spp. by ELISA were related to the numbers of flukes in the livers of 92 cattle killed in the abattoirs of Hanoi City, Vietnam. In this population, about 22% of the cattle had no flukes, another 22% had between 1 and 10 flukes, 44% between 11 and 100 flukes and 12% had more than 100 flukes in their livers. Of the 14 animals less than 2 years of age, only three were infected. At 2 years of age the mean number of flukes per liver was 10 whereas at 3 years and older, the mean varied between 60 and 80 flukes. Prevalence of infection was 78.3%. No eggs of Fasciola spp. were detected in the faeces of one third of infected cattle and 60% of the counts were less than 100 eggs per gram. The sensitivity of the egg counting method was 66.7% and specificity 100%, overall accuracy was 73.9%. Corresponding values for the ELISA method were 86.1, 70 and 82.6%, respectively. The positive and negative predictive values for the egg counting method were 100 and 45.5% and for the ELISA method were 91.2 and 58.3%, respectively.