Investigation of biosecurity risks associated with the feed delivery: A pilot study

This study explored potential biosecurity issues related to the delivery of feed to commercial farms. A pilot study was conducted to collect information about the day-to-day feed delivery, including biosecurity concerns at the level of the feed truck, the driver, and the farm. In addition, a reusable rubber boot was tested in an effort to increase the proportion of farms at which truck drivers wore clean footwear, and to explore an alternative to the standard plastic disposable boots that may be unsafe in winter conditions. Most farms did well in terms of proper dead-stock management and keeping the farm lane and feed bin areas clean. The provision of reusable rubber boots significantly increased the proportion of deliveries in which the driver wore clean footwear.     

Genetic diversity of Mycobacterium avium subspecies paratuberculosis and the influence of strain type on infection and pathogenesis: a review

Mycobacterium avium subspecies paratuberculosis (Map) is an important pathogen that causes a chronic, progressive granulomatous enteritis known as Johne’s disease or paratuberculosis. The disease is endemic in many parts of the world and responsible for considerable losses to the livestock and associated industries. Diagnosis and control are problematic, due mostly to the long incubation period of the disease when infected animals show no clinical signs and are difficult to detect, and the ability of the organism to survive and persist in the environment. The existence of phenotypically distinct strains of Map has been known since the 1930s but the genetic differentiation of Map strain types has been challenging and only recent technologies have proven sufficiently discriminative for strain comparisons, tracing the sources of infection and epidemiological studies. It is important to understand the differences that exist between Map strains and how they influence both development and transmission of disease. This information is required to develop improved diagnostics and effective vaccines for controlling Johne’s disease. Here I review the current classification of Map strain types, the sources of the genetic variability within strains, growth characteristics and epidemiological traits associated with strain type and the influence of strain type on infection and pathogenicity.     

The impact of a community-based food skills intervention on cooking confidence, food preparation methods and dietary choices - an exploratory trial

OBJECTIVE: To evaluate the feasibility of undertaking a food skills intervention study in areas of social deprivation aimed at altering cooking confidence, food preparation methods and dietary choices. DESIGN: A standardised skills programme was implemented in community-based settings. Pre- (T1) and post-intervention (T2) and 6-month follow-up (T3) measures (7-day diaries and self-administered questionnaires) were undertaken in intervention and comparison groups. SETTING: Eight urban communities in Scotland. SUBJECTS: One hundred and thirteen adults living in areas of social deprivation. RESULTS: It was clear that many subjects led fragmented lives and found commitment to intervention classes problematic. Sixty-three subjects completed the final (T3) assessments. The response to each component varied due to inability to attend sessions, illness, study requirements, employment, moving out of the area, change in circumstances, loss of interest and loss of postal questionnaires. At baseline, reported consumption of fruit and vegetables was low (mean frequency 8.1 +/- 4.78 times per week). Fruit intake increased significantly (P < 0.05) between T1 and T2 in the intervention group (1.7 +/- 2.36 to 2.7 +/- 3.28 times per week) only. Between T1 and T3, there was a significant increase (P < 0.05) in intervention subjects who reported confidence in following a recipe (67-90%,). CONCLUSIONS: This exploratory trial shows that a food skills intervention is likely to have a small but positive effect on food choice and confidence in food preparation. A full-scale randomised controlled trial in this hard-to-reach group would require a range of flexible approaches rather than a fully defined intervention, and presents challenges for trial design.     

Electrical stunning followed by decapitation or chilling of African catfish (Clarias gariepinus): assessment of behavioural and neural parameters and product quality

The objective of this study was to assess neural and behavioural responses in farmed African catfish (Clarias gariepinus) upon electrical stunning in combination with decapitation or chilling. To assess the possibility of scaling up one or both experimental methods, two trials were performed in an experimental setting. The product quality of the collected samples was compared with the currently applied industrial method: live chilling. After electrical stunning in combination with decapitation, the fish showed spikes alternated with theta and delta waves on the EEG, followed by minimal brain activity after 20±10 s. The same traces on the EEGs were observed after electrical stunning in combination with chilling. Here, minimal brain activity occurred after 22±11 s. Within a confidence level of 95%, the percentage of African catfish that was effectively stunned after administration of an electrical current of 1.5 A dm⁻², 300 V (50 Hz a.c.), followed by decapitation or chilling was above 91%. The analysis yield and evolution of liquid loss showed significant (P<0.05) differences among the batches, which could be explained by the stunning method used. The course values of the pH in the different batches were significantly (P<0.05) dependent on the stunning method, sex and location (visceral or skin side). It is concluded that African catfish can be stunned effectively using electrical stunning in a water tank, followed by decapitation or chilling in ice. Dutch commercial processors prefer to combine electrical stunning with chilling in flake ice in a rotating tumbler, as the outer slime layer is then removed, which facilitates further processing.     

The effect of substrate particle size on the production of mucus in Haliotis tuberculata L. and the importance of this in a culture system

Haliotis tuberculata, the ormer, produces mucus from secretory cells in its foot. A relationship between substrate particle size and production of mucus is demonstrated. The results are also related to the energy budget of the ormer and considered in the light of the possible culture of the organism.     

Global-scale genetic structure of a cosmopolitan cold-water coral species

• 1. When considering widely distributed marine organisms with low dispersal capabilities, there is often an implication that the distribution of cosmopolitan species is an artefact of taxonomy, constrained by the absence of characters for delimiting either sibling or cryptic species. Few studies have assessed the relationship among populations across the global range of the species' distribution, and the presence of oceanographic barriers that might influence gene flow among populations are underestimated.
• 2. In this study, evolutionary and ecological drivers of connectivity patterns have been inferred among populations of the cold-water coral Desmophyllum dianthus, a common and widespread solitary scleractinian species, whose reproduction strategy and larval dispersal are still poorly unknown.
• 3. The genetic structure of D. dianthus was explored using 30 microsatellites in 347 specimens from 13 localities distributed in the Mediterranean Sea and Atlantic and Pacific Oceans.
• 4. Results clearly reveal genetically differentiated populations in the Northern and Southern Hemispheres (F_ST = 0.16, F_SC = 0.01, F_CT = 0.15, P-values highly significant), and Chilean and New Zealand populations with independent genetic profiles.
• 5. Marine connectivity patterns at different spatial scales are discussed to characterize larval dispersal and gene flow through the Northern and Southern Hemispheres.

     

New invasive predator reduces the abundance of native prey in a cold-temperate marine fouling community

1. Invasive species threaten the conservation of marine environments, and urgent management strategies are needed to prevent their introduction, establishment and spread. Specifically, marine invasive predators destabilize ecological interactions and alter community structure and function. However, most of the evidence showing the effect of these predators is restricted to a few species and regions, while for others the information remains scarce.
2. This study experimentally evaluated the ecological effects of the sea slug Pleurobranchaea maculata, a recently introduced invasive predator, on the fouling communities of a cold-temperate port in the South-western Atlantic.
3. The results show that increasing predation pressure reduces significantly the abundance of sea anemones, which are among the preferred prey items.
4. This study reveals new evidence to help better understand the effects of P. maculata on the biological communities of a recently invaded region. Furthermore, it provides the first experimental evidence supporting the hypothesis that marine invasive predators can induce a significant decrease in the abundance of native species in benthic communities of cold-temperate marine environments in the South-western Atlantic.

     

Use of endoscopy for gender and ovarian stage determinations in Russian sturgeon (Acipenser gueldenstaedtii) grown in aquaculture

The Russian sturgeon (Acipenser gueldenstaedtii) is native to the Caspian Sea, the Black Sea and the Azov Sea. It used to breed in the main incoming rivers, until dam construction in the mid 20th century blocked upriver spawning migration. Aquaculture of Russian sturgeon has only recently begun, prompted by their declining populations in natural habitats and the rise in meat and caviar prices. However, information on their gonadal development and puberty under culture conditions is incomplete.

Because sturgeons have no external sexual dimorphism and there are no external markers for sexing, internal examination of the gonads must be employed for gender identification as well as to monitor their development. The present study describes endoscopic and histological observations of the gonads of young Russian sturgeons aimed at identifying gender and monitoring ovarian developmental stage in females up to the age of 6 years, when they enter their first puberty cycle, as well as at 7 years of age, when they have completed vitellogenesis, under culture conditions. This information, as related to fish age and size, is of vital importance to commercial farming of Russian sturgeon for caviar production and reproduction.

For gonadal observations in both sexes, we used an endoscopic system consisting of a 4 mm, 14 cm long cystoscope sheath incorporated with fiber-optic light transmission, connected to a halogen cold light source and a miniature videocamera with a control unit attached to a color monitor. This system allowed us viewing of the fish's abdominal organs, and to save pictures of selected areas of the gonads on a computer as the fish's personal record. Ovarian biopsies were taken in parallel for histology at typical stages of gonadal development.

Gender could be identified with this system as early as at 3 years of age and the sex ratio under culture conditions of females, males and unidentified gender were 55, 40 and 5%, respectively.

Not only did large differences occur in the developmental stages of female of the same age group, but also ovarian development was highly asynchronous at the early vitellogenic stages. In late vitellogenesis, at the “gray egg” stage (1600–2600 μm diameter), the oocytes were quite regular in size and color, and remained so until the final stages of maturity.

Our study suggests that endoscopy is an efficient method for both gender identification at an early age, and for determination of gonadal development stage in sturgeon aquaculture. The ability to see the whole intact gonads of anesthetized fish can reveal important management and research information, with minimal damage or stress to the fish.