Disease
within aquaculture can impact fish health and decimate stock numbers, the study
of Widanarni and Tanbiyaskur (2015) addresses the use of probiotics, prebiotics
and synbiotics (a combination of probiotics and prebiotics) through Tilapia (Oroechromis niloticus) feed to regulate the
bacteria Streptococcosis. Infection of Streptococcosis
agalactiae in O.niloticus can cause
lesions and lethargy, and in extreme cases presumed water loss from the digestive
tract leads to death. Considering the reduction in health and possible lethal
effects of S.agalactiae, its impact
on aquaculture and economy could be great.
Three
treatments were added to the Tilapia feed and tested to assess their effects on
the management of S.agalactiae. Additionally
two controls were used; one consisting of a feed with no treatment and exposure
of the fish to S.agalactiae (positive
control) and a second with no feed treatment and no exposure to S.agalactiae (negative control). Bacillus
sp. NP5 was used as the probiotic and oligosaccharides (from sweet potato) were
used as the prebiotic, the treatments were sprayed onto artificial feed. Artificial
feed was given to the fish three times a day, with the treated being
administered once a day for 14 days. On the 15th day the fish were
injected with a dose of S.agalactiae
equivalent to LD50. The parameters measured were daily growth rate (DGR), feed
conversion ratio (FCR) and survival rate.
After
injection of S.agalactiae, those
Tilapia which were treated with the probiotic, prebiotic or synbiotic possessed
an extremely low count of S.agalactiae,
the controls however possessed a substantially high count of S.agalactiae. Target organs of the liver,
kidney, brain and eyes were examined on the 3rd and 4th week
after infection by S.agalactiae, during
the 3rd week there were S.agalactiae
counts for all the treatments. By the 4th week the synbiotic treated
fish possessed no traces of the S.agalactiae.
The probiotic and prebiotic treated fish displayed presence of S.agalactiae in the brain, the positive
control displayed S.agalactiae in all
the target organs.
Of all the
treatments the most successful was the synbiotic, this provided the probiotic bacteria
with enough resource to increase their number well and increase enzyme activity.
The synbiotic increased the growth of the Tilapia due to a healthy digestive bacterial
community and activity. Due to the number of probiotic bacteria in the fish
which received the three treatments the Tilapia could efficiently digest the
food it received. This study by Widanarni and Tanbiyaskur (2015) provides clear
definitive results, although the in depth detail of the positive control biological
results described in the discussion appear to be unnecessary and detract from
the hypothesis of the study.
Widanarni
and Tanbiyaskur. (2015) Application of probiotic, prebiotic and synbiotic for
the control of streptococcosis in Tilapia Oreochromis niloticus. Pakistan Journal of Biological Sciences.
18 pp.59-66
Hi Emma - a great post!
ReplyDeleteI wondered, in the long term do you think that the bacteria of the pro- and syn-biotics actually colonise the GI tract of the fish and alter the microflora, or are these benefits observed because of the frequency of feeding?
Some of the literature I've read suggested that the microfloral composition of the parents can influence that of the offspring. In respect to the pro- and syn-biotics do you think they will have some trans-generational impact?
Thanks again!
Jack
Hi Emma,
ReplyDeletethis is an interesting post. Initially i thought it would be the probiotic treatment that would result in the lowest infection rate. But its interesting that its the synbiotic shown the best result.
To Jack's question, i was just thinking, if the microfloral composition were to be passed to the offspring, would the genome sequence changed as well? because the group of commensal bacterial in each individuals would be different?
Thank you.
Li
Hi Li,
DeleteI'm not too sure if your question was directed at me. But anyway, I'm not sure if the microflora are passed to the offspring, or merely influenced by the parents. I cannot seem to find any means by which the microbes would be transferred in the literature. With the genome sequences, were you referring to that of the parents, offspring or microbes themselves?
If your question wasn't directed at me - apologies!
Jack
DeleteHi Jack and Li,
I thought I would answer your questions together as they are very closely linked.
Concerning the pro and syn-biotics in the GI tract of the fish, I believe they would colonise during the treatment feeding and would remain after the treatment, although possibly at a lower level. It would be interesting to see if the intestinal bacterial community naturally adjusts in diversity when the pro, pre and syn-biotics are no longer added to the feed though.
The synbiotic treatment had a greater effect as it provides probiotics which improve the Tilapia digestive system increasing the efficiency of food absorption, it also provides prebiotics which improve the number and metabolic activity of the intestinal bacteria. With the combined effect of the symbiotic treatment the GI tract can provide the fish with a greater immune system and nutrition from its feed.
I am not sure if the presence of the microflora composition from the pro, pre and syn-biotics would be passed from the parents to the next generation, they are introduced through feed rather than being a natural occurrence in the digestive system. I do remember that we had a seminar from the personal research module which covered similar trans-generation impact though; unfortunately I do not possess the notes from the seminar. Additionally, as this study is so recent there does not appear to be any further work concerning these particular “biotics” and Tilapia. Jack, you mentioned you had found studies which addressed this theory, by any chance could you add the link to these conversations so I could also read them as I haven’t had much luck.
Thanks
Emma