Growth of Black Soldier Fly Larvae Reared on Organic Side-Streams

Round 1

Reviewer 1 Report

This paper described the capacity of BSF larvae to process 12 organic side-streams (mono-streams) and 2 standard substrates (chicken start mash and 12 Gainesville diet) for the biowaste recycle treatment. The experiment work is a lot, which I do respect. The data analysis, especially the statistical analysis is limited, which results the novel findings are little. I have a few comments, which are a little bit serious, but they could be helpful to improve the quality of this work.

 

1. The introduction part is not good. The line 31-69 generally described the common sense to people who work in the black soldier fly larvae (BSFL) field. As I understood, introduction should describe why you do your work, and what could be newly discovered in your work. The references 31-53 were only showed in the discussion part, but none of them were described in the introduction part. However, these references are the reasons why you do your work, aren’t they? You need to describe what have been done in these works and what haven’t been done, what could be different between your work and these references. If you say nothing about these references, doesn’t it mean everything has been done, and what you did is just another prove that they are right or generally right. Thus, the introduction part may need to be seriously rewrote.

 

2. Line 121-122 this part is not clear and somehow conflict. The There are 12 feed substrates, and 2 complex substrates, the author should describe the conversion factor from Kjeldahl N to crude protein one by one, and combine the substrates using the same conversion factor together, saying the rest materials used the factor of 6.25. And in line 121, the N to P factor should be changed to N to crude protein factor, since P was used as the short term of phosphate in other part of the work, like in the Table 2.

 

3. Line 143, what is RADIUS group?

 

4. Line 181-190 is the statistical analysis, which should be list as a separate paragraph, part 2.5. Although there is description of statistical analysis, the data didn’t seem to be analyzed, since there were no p value or differences data for any of the tables

   In the line 349-356, the statistical results of these part are inconvincible. First of all, there should be statistical evidence explaining why only two parameters were reserved in the regression analysis, secondly, what is the formula of the regression analysis in Fig4.b; thirdly, the analysis is quite limited, the PCA/RDA/NMDS analysis or the correlation analysis could be used for data analysis to support the final result of Fig4.b.

   Fig4. b, the blue line is not necessary.

 

5. Table5 and Fig.1 are the same information, similar to the Table6 and Fig.3. Figures are not necessary.

 

6. Fig2, the X axis was from Day7-Day15. It is better to change the time line to the Day 0-9. Since the feeding experiment lasted for 9 days (line 157), using Day 0-9 is easier for readers to follow the results.

 

7. The discussion part using the substrate type as the main clue to compare the difference between the current results and previous references. Actually, other than the substrate type, the chemical parameters could be another clue to explain the findings of these data. To be honest, what is discussed through the substrate clue is actually obvious to the people who work in this field. Without the discussion, I can judge from your table about the background reasons. What I don’t know, or what I am interested to understand is the background chemical reasons for these results. The current results seem to me that either the protein to non-fiber carbohydrate ratio plus the gross energy content, or the minimum amount of protein and NFC were the crucial factor for the BSFL growth and waste bioconversion process. The author could use the statistical analysis as the main tool to explore this understanding. And then, rewrite the discussion part through the chemical clue. Therefore, these results could be useful to people who need to design a waste system with combined different type of waste. Again, to deeply discuss the results through chemical parameters, dig the data with statistical tools is very much necessary. The statistical analysis as it is now seems to me that the author didn’t really do or understand what is analyzed and what should be further done. The whole work costed lost of time, manual effort and money, and the results are good and useful to the field, which I do respect. The author just needs to dig the background chemical reasons a little bit further, which will make the work more valuable and novel. 

Author Response

Dear reviewer,

Thanks a lot for your review. We really appreciate all of your efforts of going through this paper. Even though there was a lot addressed, we're indeed certain this was fair feedback. We've spent a lot of hours and even addressed an extra person with a better statistical background to help us make this paper better. We really hope this revised paper will be more valuable for the sector. Still, we worked with side-streams and some factors were just not controllable. Therefore we are currently exploring the possibility of using artificial substrates to enhance the potential of modelling larval growth based on macronutrient composition. Hopefully this will result in more clear main/interaction effects.

Wish you all the best,
Kind regards,
Laurens

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear Authors, I read your manuscript "Growth of Black Soldier Fly Larvae Reared on Organic Side-2 Streams ". In the attach file you can find my comments and suggestions.

Best regards

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

Thanks a lot for your review. We really appreciate all of your efforts of going through this paper. We're indeed certain this was fair feedback. We've spent a lot of hours and even addressed an extra person with a better statistical background to help us make this paper better. We really hope this revised paper will be more valuable for the sector. 

Wish you all the best,
Kind regards,
Laurens

Author Response File: Author Response.pdf

Reviewer 3 Report

Materials and Methods

Past tense rather than present tense should be used throughout the methods section

More detail on the source and constituents of the side streams is required. For example, where was household food waste collected, how long had waste streams been stored prior to arrival, what fruits were in the fruit puree, what vegetables were in the vegetable overproduction etc.

The authors state that some of the substrates were oven-dried prior to use. The authors should consider the potential effect of this on the nutrients and microbial populations in these substrates.

The time over which the 1 f of eggs was collected should be stated.

The dry matter content of the initial chick feed diet used (first 7 days) should be provided.

Results

In all tables it should be ststed what the figures represent i.e. mean +/- sd or se

A great proportion of the results is given to the analysis of the substrates. A comparison with other readily available data on many of these substrate types should be provided. It would have been useful if amino acid and fatty acid analysis had been included.

The dry matter content of the larvae reared on the different substrates should be provided. The mass and dry matter of the larvae at the start of the feeding experiment should be included.

The authors should consider whether Figures 1 and 3 are needed as the data is presented in tables.

Figure 2 - as larvae were not weighed on days 4 and 5 of the feeding experiment this should be indicated in the figure

Discussion

Is it known whether any insecticides were used on the tomato plants from which the tomato leaves were collected?

The discussion repeats much of the data in the results section. The authors should consider whether the discussion can be made more succinct.

Author Response

Dear reviewer,

Thanks a lot for your review. We really appreciate all of your efforts of going through this paper. We're indeed certain this was fair feedback. We've spent a lot of hours and even addressed an extra person with a better statistical background to help us make this paper better. We really hope this revised paper will be more valuable for the sector. 

Wish you all the best,
Kind regards,
Laurens

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The revised version is good. I have no more comments.

Reviewer 2 Report

Dear Authors, I have read again your manuscript and the quality has been implemented, following the comments suggested by the reviewers.

Best regards