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Optimisation and standardisation of functional immune assays for striped catfish (Pangasianodon hypophthalmus) to compare their immune response to live and heat killed Aeromonas hydrophila as model...

Optimisation and standardisation of functional immune assays for striped catfish (Pangasianodon hypophthalmus) to compare their immune response to live and heat killed Aeromonas hydrophila as model... | Aquaculture Directory | Scoop.it

Aquaculture production of Pangasianodon hypophthalmus is growing rapidly in South East Asia, especially in Vietnam. As it is a relatively new aquaculture species there are few reports evaluating its immune response to pathogens. Thus, functional assays for P. hypophthalmus were optimised to evaluate both innate and adaptive immune responses, and were then used to examine immune response following stimulation with live and heat-killed Aeromonas hydrophila. These were used as models of infection and vaccination, respectively.

Four treatment groups were used, including a control group, a group injected intraperitonally (IP) with adjuvant only, a group injected with heat-killed A. hydrophila (1 × 109 cfu ml−1 mixed with adjuvant), and a group injected with a subclinical dose of live A. hydrophila. Samples were collected at 0, 1, 3, 7, 14 and 21 days post-injection (d.p.i.) to assess their immune response. The results indicated that challenge with live or dead bacteria stimulated the immune response in P. hypophthalmus significantly above the levels observed in control groups with respect to specific antibody titre, plasma lysozyme and peroxidase activity, and phagocytosis by head kidney macrophages at 7 or/and 14 d.p.i. At 21 d.p.i., total and specific antibody (IgM) levels and plasma lysozyme activity in fish injected with either live or dead A. hydrophila were significantly different to the control groups. Differential immune responses were observed between fish injected with either live or dead bacteria, with live A. hydrophila significantly stimulating an increase in WBC counts and plasma peroxidase activity at 3 d.p.i., with the greatest increase in WBC counts noted at 21 d.p.i. and in phagocytosis at 14 d.p.i. By 21 d.p.i. only the macrophages from fish injected with dead A. hydrophilashowed significantly stimulation in their respiratory burst activity. This study provides basic information on the immune response in pangasius catfish that can be useful in the health control of this species.

 (Wanna Sirimanaponga, Kim D. Thompsona, Kan Kledmaneeb, Prawporn Thaijongrakb, Bertrand Collet, Ei Lin Ooi & Alexandra Adams IN  Fish & Shellfish Immunology, 40(2) 374-383 - October 2014).


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John Bostock's curator insight, August 13, 2014 8:24 AM

Excellent article from Dr Sirimanapong and colleagues available on open access until October 2014.

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Inbreeding and disease in tropical shrimp aquaculture: a reappraisal and caution

Inbreeding and disease in tropical shrimp aquaculture: a reappraisal and caution | Aquaculture Directory | Scoop.it

NACA recommends that anyone involved in shrimp aquaculture - particularly hatcheries but also anyone procuring PL - read a paper by Roger Doyle, recently published in Aquaculture Research which discusses the link between inbreeding and disease in tropical shrimp aquaculture:

 

"The disease crisis facing shrimp aquaculture may be propelled, in part, by an interaction between management practices that cause inbreeding, and the amplification by inbreeding of susceptibility to disease and environmental stresses. The study describes and numerically simulates gene flow from Penaeus (Litopenaeus) vannamei hatcheries that employ a ‘Breeder Lock’ to discourage use of their PL as breeders, through ‘copy hatcheries’ that breed the locked PL, to inbred shrimp in farm ponds. Re-analysis of published data shows that inbreeding depression under stress is exceptionally strong in shrimp. Inbreeding is currently overlooked as a problem because: (1) procedures recommended for well-managed hatcheries do not consider their implications for the copy hatcheries that supply most farmed shrimp (estimated 70%), (2) inbreeding in hatcheries is often reported as zero even though zero is the mathematical expectation of the usual estimator (Fis, fixation index) whatever the true genealogy of the broodstock. Simulation shows, however, that inbreeding can be estimated with Wang's trioML estimator, that Fis can differentiate Breeder Locked from copy PL and that simple tests can verify the lock status of PL. The importance of inbreeding should be re-evaluated in the context of disease and environmental stress. Unrecognized inbreeding may increase the incidence, prevalence and lethality of WSSV, IHHNV, EMS (AHPND) and other diseases."

 

DOI: 10.1111/are.12472


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John Bostock's curator insight, May 24, 2014 4:39 AM

Interesting and challenging paper.

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Development of chitosan conjugated DNA vaccine against nodavirus in Macrobrachium rosenbergii (De Man, 1879) - Ramya - 2013 - Journal of Fish Diseases - Wiley Online Library

Development of chitosan conjugated DNA vaccine against nodavirus in Macrobrachium rosenbergii (De Man, 1879) - Ramya - 2013 - Journal of Fish Diseases - Wiley Online Library | Aquaculture Directory | Scoop.it

The protective efficacy of a DNA construct containing extra small virus antisense (XSVAS) gene of nodavirus encapsulated with chitosan nanoparticles (NPs) was investigated in giant freshwater prawn Macrobrachium rosenbergii (De Man, 1879). The delivery was carried out using oral and immersion methods. A plasmid concentration of 100 ng μL−1 when conjugated with chitosan NPs was found to be more effective in increasing the survivability of the infected prawn. The particle mean size, zeta potential and loading efficiency percentage were 297 nm, 27 mV and 85%, respectively. The ability of the chitosan to form a complex with the plasmid was studied by agarose gel electrophoresis. The NPs were characterized by atomic force microscopy (AFM). Persistence study showed the presence of the DNA construct up to 30th day post-treatment. The oral treatment was found to be better than the immersion treatment for delivery of the chitosan-conjugated DNA construct. This is probably the first report on the delivery of nanoconjugated DNA construct in M. rosenbergii, against nodavirus.


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Prebiotics as immunostimulants in aquaculture: A review

Prebiotics as immunostimulants in aquaculture: A review | Aquaculture Directory | Scoop.it

Fish & Shellfish Immunology 40 (1) 40-48

 

Prebiotics are indigestible fibers that increase beneficial gut commensal bacteria resulting in improvements of the host's health. The beneficial effects of prebiotics are due to the byproducts generated from their fermentation by gut commensal bacteria. In this review, the direct effects of prebiotics on the innate immune system of fish are discussed. Prebiotics, such as fructooligosaccharide, mannanoligosaccharide, inulin, or β-glucan, are called immunosaccharides. They directly enhance innate immune responses including: phagocytic activation, neutrophil activation, activation of the alternative complement system, increased lysozyme activity, and more. Immunosaccharides directly activate the innate immune system by interacting with pattern recognition receptors (PRR) expressed on innate immune cells. They can also associate with microbe associated molecular patterns (MAMPs) to activate innate immune cells. However, the underlying mechanisms involved in innate immune cell activation need to be further explored. Many studies have indicated that immunosaccharides are beneficial to both finfish and shellfish.

  


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John Bostock's curator insight, July 27, 2014 9:21 AM

This should be a helpful review for anyone wanting to know more about prebiotics for aquatic animals

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The IPN virus in Atlantic salmon (Salmo salar L) – the correlation between acquired immunity and biomarkers for infection - NVH

The IPN virus in Atlantic salmon (Salmo salar L) – the correlation between acquired immunity and biomarkers for infection - NVH | Aquaculture Directory | Scoop.it

A PhD project carried out at the Norwegian School of Veterinary Science has studied immunity to IPN in salmon by using different injected vaccines. The study focused particularly on the identification of biological markers as a measure of immunity to IPN.

 

In his doctoral research project, Hetron Mweemba Munang’andu compared the use of traditional vaccines (based on whole, inactivated viruses) against IPN with new ways of administering viral antigens, including plasmid vaccines, subunit vaccines and nanoparticle vaccines. His results show that traditional, inactivated vaccines are more effective than vaccines made by molecular biological methods.


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Novel insights into the peritoneal inflammation of rainbow trout (Oncorhynchus mykiss)

Novel insights into the peritoneal inflammation of rainbow trout (Oncorhynchus mykiss) | Aquaculture Directory | Scoop.it

The peritoneal cavity has been extensively used as a laboratory model of inflammation in many species, including the teleost fish. Although, the peritoneal cavity of rainbow trout (Oncorhynchus mykiss) was previously shown to contain a resident population of leukocytes, closer information about their exact composition and their functional response to pathogens is still missing. In the presented work, flow cytometric analysis using monoclonal antibodies was performed to characterize this cell population and evaluate its traffic during the first 72 h after antigenic stimulation and infection with Aeromonas salmonicida. Obtained results indicate that the unstimulated peritoneal cavity represents rather a lymphoid niche, dominated by the IgM+ B cells. Expectedly, the composition changed rapidly after stimulation, which resulted in two complete changes of dominant cell type within first 72 h post injection. While the first stage of inflammation was dominated by myeloid cells, lymphocytes predominated at the later time points, with IgM+B cells representing more than two thirds of all cells. Later, the infection experiment elucidated the peritoneal infection and identified the key differences to the antigenic stimulation. Additionally, the data indicate that the resolution of the inflammation depends more on the bacterial clearance by myeloid cells than on regulation by lymphocytes. Taken together, obtained results represent the first complete description of the immune reaction protecting the peritoneal cavity of the fish and shed some light on the conservation of these processes during the evolution.


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