Reduced Infestation Levels of Lepeophtheirus salmonis in Atlantic Salmon (Salmo salar) following Immersion Exposure to Probiotic Aliivibrio spp.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper presents the findings from three trials to study the infestation levels of Lepeophtheirus salmonis in Atlantic salmon (Salmo salar) following immersion and spray exposure to probiotic Aliivibrio spp. The authors reported a significant reduction in lice infestation trials 91 and 155 days after Aliivibrio spp. exposure by immersion or spray with a reduction in salmon lice attachment of 58 to 65 %, although in a lice infestation trial 55 days after Aliivibrio spp. exposure, no initial reduction was seen, although a second count revealed a reduction associated with the probiotic application. The authors demonstrated interesting results associated to probiotic exposure, and I believe there is much merit to the data presented in this paper, as well as the findings are important for sustainable fish production. However, problems were observed in the manuscript, fact that compromises its publication thereby. I would encourage the authors to adjust the manuscript to publish it in this important journal. In this context, the following comments should be addressed:

- In several instances, the bibliographic references supporting the paper's scientific foundation are outdated. Example: lines 47 and 48 (Pickering and Pottinger, 1989) about cortisol and stress, many other authors presented new discussions about immunosuppression. Other example lines 55 and 56 “…salmon that attract copepodids and induce attachment, are largely unknown (Mordue and Birkett, 2009).” almost 15 years, nobody discussed this question in this period? Again in lines 80 and 81 “In fish, probiotic interventions have traditionally been delivered by inclusion in feed and shown to influence innate immunity (Gómez and Balcázar, 2008), this point has been exhaustively studied, and many improvements were observed during this period. Therefore, I recommend that authors re-read the text carefully and adjust these points to strengthen the article scientific foundation.

- In the introduction section should describe better Allivibrio spp. bacteria (taxonomically).

- Item 2.1 should be better presented, it is confused for readers. I understood only after reading the paper more than once.

- Lines 133 to 139, authors do not need to provide the precise address of the laboratory, since this information is present in the authors' affiliation in the title page.

- Lines 148 and 149, It is not necessary to repeat the laboratory and location, just enter the laboratory acronym presented previously.

- Line 164, The term “freshwater” is right? Isn't it salt water?

- Line 217 - Isn't it 55 days (Table 1) or 58 days?

- Line 219 - Isn't it 93 days (Table 1) or 123 days?   

- Although the trial designs are interesting, the difference between times, doses (composition of probiotics) and types of administration make discussions of their findings complex. The authors cited the importance of stress in fish immunosuppression. Therefore, when I studied population density (storage density in each trial) in the paper, they were very different: 1 trial (3 kg/tank, representing 16.7 kg/m3), 2 trial (2.1 kg/tank, representing 11.7 kg/ m3) and 3 trial (1.5kg/tank, 8.3 kg/m3). In this context, the proximity of fish due to population density, their size and possible immunosuppression should be the subject of discussion in this study.

 

- In the discussion section, the authors need to demand more attention to better discuss their findings and the differences among proposed trials, since the paper discussion is superficial and did not take into account these significant differences in their findings. On the other hand, although it is not conventional, it may be a strategy for the authors to divide the discussion into sub-items, in my opinion a discussion in plain text is better, if the authors choose to keep the discussion in sub-items I recommend that they be addressed like 4.1, 4.2, 4.3 and 4.4 (not as presented in items 5, 6, 7 and 8).

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

There are false sentences in the manuscript, for example "Farmed Atlantic salmon are infested with the salmon louse (Lepeophtheirus salmonis) in commercial farms". It should be clear to the Authors that not all salmon are infected. Moreover, the manuscript is difficult to read. In particular, the abstract is difficult to read and poorly illustrates the content of the manuscript. Unfortunately, the manuscript lacks basic information, such as the size and weight of the fish and the physicochemical parameters of the water. This information must be added (if measured). Otherwise, the manuscript should be rejected.

Author Response

Please see the attachment

Author Response File: Author Response.docx