Over the years aquaculture has grown into a successful industry accounting for almost 50% of fish sales worldwide in 2006. This increasing demand has lead to mass husbandry resulting in the presence of pathogenic disease and therefore the overuse of antibiotics and chemotherapeutics. This overuse of antibiotics has caused the rapid evolution of resistance mechanisms and selected for resistance genes, hence leading to the presence of resistant and more virulent microorganisms. Asian aquaculture has been particularly hard hit by disease, for example shrimp industries in Bangladesh which provide the second largest exportable commodity for the country, have had devastating incidences of disease, which has been no doubt facilitated by the cramped and overcrowded rearing ponds and tanks used.
Over the years several methods of disease control have been looked into; however the addition of large amounts of antibiotics and chemotherapeutics remains the current method of choice for disease control. Recently the emergence of non-pathogenic bacteria as bio-control agents has received a lot of attention, as these probiotics help to strengthen already existing microbial communities in the environment and gut of the organisms in question. Several studies have backed up the use of probiotics claiming that even pathogens which have become unaffected by antibiotics could be controlled by the use of probionts (E.g. V.harveyi).
The aims of this study were to isolate pathogenic micro-organisms and probiotic bacteria from shrimp culture ponds in a region of Bangladesh. The authors tested these pathogens and probionts to see if the use of probiotics would have a beneficial and sustainable effect in aquaculture. The results of their study indicated that a good number of probionts challenged pathogens successfully, giving evidence of beneficial properties, although it was indicated that the effectiveness of the probionts is dependent on which pathogens were present. Further studies were also carried out to ensure the safety of the probionts in mammalian systems (an important food safety issue) with results showing that 19/37 of the probionts would be safe for mammals and therefore potentially humans if ingested.
The authors state that further research is required to develop suitable probiotics along with full scale trials and appropriate monitoring tools; however the future of this developing science seems promising. Overall I think that this paper had a good purpose, although I found throughout that it was very badly written. The English used was often incorrect and the description of the methods and results were more complicated than they needed to be. The paper was quite short and I found the structure of it a bit all over the place, however I think that the overall point of the study was a good one with encouraging results that can be expanded on in the future.
Review of: Rahman, S. Khan, S. N. Naser, M. N and Karim, M. (2009) Application of probiotic bacteria: A novel approach towards ensuring food safety in shrimp aquaculture. Journal of Bangladesh Academy of Science. 33(1) 139-144.
5 comments:
This study shows significant progress in the current trends in research investigating the implementation of an effective and sustainable alternative to antibiotic use in many marine environments. Another option that could be explored in this case, and is currently in use, is the design of multivalent vaccines such as those protecting invertebrates against a range of bacterial pathogens including Vibrio spp. This option would avoid the use of antibiotics and chemotherapeutic agents and the use of probiotics which, although easily removed through effective heat inactivation, could still pose an issue to those in high risk groups (gestating women, immuno-compromised individuals, etc.). I found this paper really insightful with regards to the immune systems and route of infection in shrimp : Rowley, A., Powell, A.; 2007; Invertebrate Immune Systems - Specific, Quasi-Specific or Non-Specific?; Journal of Immunology; 179(11); p7209-14. Maybe greater understanding of the mechanics of infection in shrimp could help to target probiotics more specifically to limit their risk to the human population.
Thanks it would be good to read another paper on the subject. Like you said I think the authors had the best intentions from the study but this paper made the project seem a bit rushed and low budget! I agree with you that its important to understand the mechanisms behind infections as changing from antibiotics to probiotics is better but I can see the same thing happening with reference to the ability of the pathogens to overpower and acquire more resistance genes!
hi girls,interesting paper and comments as well..
I strongly agree with you about the use of probiotics instead antibiotics,especially in farmed animals, as it could affect human beings too.
Since I recently posted a review on PSP and NSP intoxication in shrimp aquaculture I was wondering if the probiotics can be involved in challenged also toxic microalgae or in modulating the effects of toxins released by microalgae...I know it was not the aim of this study and the project was low budjet so perhaps they did not go in depth but did they mention anything about this application of probiotics???
Hey Valentina, I'm not sure they would have much effect on toxic microalgae as probiotics are not therapeutic agents they just help to promote the good bacteria living in a organisms gut or in aquaculture ponds/tanks. Theoretically I suppose it could be a good idea however I don't think they're at that stage yet and a lot more work would have to be carried out. The authors did not mention anything about the application of probiotics other than that they are biocontrol agents but that they do have the ability to change microbial composition in aquaculture,So if there are bacteria present which have the ability to resist microalgae toxin then I suppose they could be boosted!
yes I meant that maybe probiotics can promote bacteria able to resist to toxic microalgae...could be nice to know..thank you anyway for your help!
Post a Comment