Larval development in European hake (Merluccius merluccius L.) reared in a semi-intensive culture system

Eggs of European hake (Merluccius merluccius L.) were stripped from fish caught at sea. Larvae were kept under semi‐intensive conditions at around 12°C. In addition, eggs were incubated in single wells at 9.2, 12.7 and 14.5°C, where hatching, development and survival were closely examined. During the larval stage, a total of 299 larvae were sampled to follow development and growth. In addition a small number of juveniles were sampled. Larvae hatched approximately 4 days after fertilization, and were 2.9 mm in total length (TL). At 6‐day post hatching (dph), the larvae were 4.1 mm (TL), the jaw apparatus was developed, and the larvae had started to feed. Most of the growth during the early larval period is restricted to the head, and there is almost no increase in length for the first 3–4 weeks post hatching. Teeth and pelvic fins appear at 25 dph. Development of unpaired fins at approximately 30 dph marks the start of the larval–juvenile transition. Weaning to formulated feed was accomplished 50 dph, when external morphology was similar to that of adult hake.     

Evaluation of the effect of commercially available plant and animal protein sources in diets for Atlantic salmon (Salmo salar L.): digestive and metabolic investigations

The present study investigated the effect of various alternative diet ingredients partially replacing fishmeal (FM) on digestive and metabolic parameters in Atlantic salmon (Salmo salar L.) post-smolts (initial body mass 305 ± 69 g) following 12 weeks of feeding. Experimental diets containing 20 % extracted sunflower (ESF), pea protein concentrate (PPC), soy protein concentrate (SPC), feather meal (FeM) and poultry by-product (PBY) were compared to a reference diet containing FM as the main protein source. For the different intestinal compartments trypsin, lipase, bile salts, dry matter and chyme-associated leucine aminopeptidase (LAP) were measured from the content and LAP was measured in the tissue. Selected metabolites were measured in plasma samples. In general, use of plant proteins resulted in low C-LAP activity, low plasma cholesterol and high plasma magnesium. The plasma levels of cholesterol and Mg reflecting were most likely reflections of the composition of the diet, while the LAP activity in chyme may indicate lower epithelial cell turnover. Other responses varied depending on the plant protein source. Results from the animal protein substitution also varied both between diets and compartments; however, both materials increased lipase activity in DI. FeM resulted in a significant increase in both total and specific LAP activities suggesting an attempt to increase the digestive capacity in response to low digestibility of the diet while PBY showed very little difference from the FM-fed control fish. The present trial indicates that 20 % PPC, SPC and PBY can partially replace FM in diets for Atlantic salmon. The qualities of ESF and FeM used in this trial show little promise as FM replacement at 20 % inclusion level.     

Direct measurement of the reaction front in chemically amplified photoresists

The continuing drive by the semiconductor industry to fabricate smaller structures using photolithography will soon require dimensional control at length scales comparable to the size of the polymeric molecules in the materials used to pattern them. The current technology, chemically amplified photoresists, uses a complex reaction-diffusion process to delineate patterned areas with high spatial resolution. However, nanometer-level control of this critical process is limited by the lack of direct measurements of the reaction front. We demonstrate the use of x-ray and neutron reflectometry as a general method to measure the spatial evolution of the reaction-diffusion process with nanometer resolution. Measuring compositional profiles, provided by deuterium-labeled reactant groups for neutron scattering contrast, we show that the reaction front within the material is broad rather than sharply defined and the compositional profile is altered during development. Measuring the density profile, we directly correlate the developed film structure with that of the reaction front.     

Antimicrobial potential of egg yolk ovoinhibitor, a multidomain Kazal-like inhibitor of chicken egg

Chicken egg ovoinhibitor is a multidomain Kazal-type serine protease inhibitor with unknown function. Comparison of expression between different tissues indicated that ovoinhibitor is highly expressed in the magnum and liver followed by the uterus, which secrete egg white, egg yolk, and eggshell precursors, respectively. The results also revealed that ovoinhibitor expression is increased in the liver during sexual maturation followed by a subsequent decrease in mature hens. Ovoinhibitor was purified from the egg yolk plasma from nonfertilized eggs using two consecutive affinity chromatographies and gel filtration. Purified egg yolk ovoinhibitor was shown to inhibit trypsin and subtilisin. It was shown that purified egg yolk ovoinhibitor exhibited antimicrobial activities against Bacillus thuringiensis . The results suggest that this anti-protease plays a significant role in antibacterial egg defense against Bacillus spp., preventing contamination of table eggs (nonfertilized eggs) and protecting the chick embryo (fertilized eggs).     

The apparent prevalence of skin lesions suspected to be human-inflicted in Danish finishing pigs at slaughter

Skin lesions on pigs inflicted by humans compromise animal welfare and are the subject of increased public and political attention in Denmark. Systematic surveillance of such skin lesions was enforced in April 2010 at all Danish pig abattoirs, through the recording of meat inspection Code 904 for the presence of skin lesions suspected to be human inflicted. The objectives of the present study were to (a) estimate the apparent prevalence of Code 904s at the pig and herd owner level; (b) characterise the distribution of deliveries with pigs demonstrating a Code 904; (c) characterise the distribution of herd owners with repeated Code 904 recordings; and (d) determine the developments in Code 904 prevalence over time in Danish finishing pigs in the period from May 1, 2010 to September 30, 2013.     

A class of potent antimalarials and their specific accumulation in infected erythrocytes

During asexual development within erythrocytes, malaria parasites synthesize considerable amounts of membrane. This activity provides an attractive target for chemotherapy because it is absent from mature erythrocytes. We found that compounds that inhibit phosphatidylcholine biosynthesis de novo from choline were potent antimalarial drugs. The lead compound, G25, potently inhibited in vitro growth of the human malaria parasites Plasmodium falciparum and P. vivax and was 1000-fold less toxic to mammalian cell lines. A radioactive derivative specifically accumulated in infected erythrocytes to levels several hundredfold higher than in the surrounding medium, and very low dose G25 therapy completely cured monkeys infected with P. falciparum and P. cynomolgi.     

Herd diagnosis of low pathogen diarrhoea in growing pigs – a pilot study

Background

The major indication for antibiotic use in Danish pigs is treatment of intestinal diseases post weaning. Clinical decisions on antibiotic batch medication are often based on inspection of diarrhoeic pools on the pen floor. In some of these treated diarrhoea outbreaks, intestinal pathogens can only be demonstrated in a small number of pigs within the treated group (low pathogen diarrhoea). Termination of antibiotic batch medication in herds suffering from such diarrhoea could potentially reduce the consumption of antibiotics in the pig industry. The objective of the present pilot study was to suggest criteria for herd diagnosis of low pathogen diarrhoea in growing pigs.Data previously collected from 20 Danish herds were used to create a case series of clinical diarrhoea outbreaks normally subjected to antibiotic treatment. In the present study, these diarrhoea outbreaks were classified as low pathogen (<15% of the pigs having bacterial intestinal disease) (n =5 outbreaks) or high pathogen (≥15% of the pigs having bacterial intestinal disease) (n =15 outbreaks). Based on the case series, different diagnostic procedures were explored, and criteria for herd diagnosis of low pathogen diarrhoea were suggested. The effect of sampling variation was explored by simulation.

Results

The diagnostic procedure with the highest combined herd-level sensitivity and specificity was qPCR testing of a pooled sample containing 20 randomly selected faecal samples. The criteria for a positive test result (high pathogen diarrhoea outbreak) were an average of 1.5 diarrhoeic faecal pools on the floor of each pen in the room under investigation and a pathogenic bacterial load ≥35,000 per gram in the faecal pool tested by qPCR. The bacterial load was the sum of Lawsonia intracellularis, Brachyspira pilosicoli and Escherichia coli F4 and F18 bacteria per gram faeces. The herd-diagnostic performance was (herd-level) diagnostic sensitivity =0.99, diagnostic specificity =0.80, positive predictive value =0.94 and negative predictive value =0.96.

Conclusions

The pilot study suggests criteria for herd diagnosis of low pathogen diarrhoea in growing pigs. The suggested criteria should now be evaluated, and the effect of terminating antibiotic batch medication in herds identified as suffering from low pathogen diarrhoea should be explored.

Electronic supplementary material

The online version of this article (doi:10.1186/2046-0481-67-24) contains supplementary material, which is available to authorized users.     

Low prevalence of zoonotic multidrug‐resistant bacteria in veterinarians in a country with prudent use of antimicrobials in animals

The occurrence of multidrug‐resistant zoonotic bacteria in animals has been increasing worldwide. Working in close contact with livestock increases the risk of carriage of these bacteria. We investigated the occurrence of extended‐spectrum beta‐lactamase (ESBL) and plasmidic AmpC beta‐lactamase producing Enterobacteriaceae (ESBL/pAmpC‐PE) and livestock‐associated methicillin‐resistant Staphylococcus aureus (LA‐MRSA) in Finnish veterinarians (n = 320). In addition to microbiological samples, background information was collected. Bacterial whole genome sequencing was performed to deduce sequence types (STs), spa types and resistance genes of the isolates. In total, 3.0% (9/297) of the veterinarians carried ESBL producing Escherichia coli, with one ESBL producing E. coli isolate producing also AmpC. Seven different STs, sequences of several different plasmid groups as well as several different bla_ESBL/pAmpC genes existed in different combinations. No carbapenemase or colistin resistance genes were detected. MRSA was detected in 0.3% (1/320) of the samples. The strain belonged to LA‐MRSA clonal complex (CC) 398 (ST398, spa type 011, lacking Panton‐Valentine leukocidin genes). In conclusion, this study shows low carriage of multidrug‐resistant zoonotic bacteria in Finnish veterinarians. However, finding LA‐MRSA for the first time in a sample from a veterinarian in a country with prudent use of animal antimicrobials and regarding the recent rise of LA‐MRSA on Finnish pig farms, a strong recommendation to protect people working in close contact with animals carrying LA‐MRSA CC398 is given. Further studies are needed to explain why the prevalence of LA‐MRSA in veterinarians is lower in Finland than in other European countries.     

Sexual and somatic hybridization in the genus Lactuca

Summary Various genes for disease resistance identified in wild Lactuca are difficult, even impossible to exploit in lettuce breeding, due to sexual incompatibility between L. sativa and wild Lactuca sp. We adapted two cellular biology techniques to overcome these interspecific barriers: in vitro embryo rescue and protoplast fusion. In vitro rescue of immature embryos was used successfully for sexual hybridization between L. sativa and L. virosa. Vigorous hybrid plants were produced between L. sativa and seven accessions of L. virosa. Protoplast fusion permitted the regeneration of somatic hybrids between L. sativa and either L. tatarica or L. perennis. Hybrids between L. sativa and L. tatarica were backcrossed to L. sativa.