The Effect of Solid-State Fermentation on the Nutritive Value of Rapeseed Cakes and Performance of Broiler Chickens

Round 1

Reviewer 1 Report

This study aimed to assess the applicability of eleven different products of solid-state fermentation of rapeseed cakes with commercial enzyme additives on fermentation parameters and parameters of growth of a broiler experiment. The study is interesting and within the scope of the journal. I recommend acceptance of this manuscript after addressing the appended comments.

Line 28-29: the conclusion should be edited to represent the outcome of this study. Please address this point.

Line 58: our previous studies instead of Our studies

Line 59: please add a brief on different exogenous enzyme preparations.

Line 69: please refer to the parameters of “performance”.

Line 70: a diagrammatic figure should be used to better explain the methodology. I recommend this, please.

Line 177: Please describe the statistical model well (mention the factors, levels, and tools).

Line 175-181: the authors should explain the measured parameters among the studied groups, the type of sampling, when the samples were extracted, and others.

Line 234: these results should be highlighted in the methodology?

Line 248: discussion section does not have subtitles. Please follow the guidelines of the journal for this issue.

Line 351-358: the authors should explain the findings of this study, rather than demonstrating similarities of finding with previous records or studies. Please explain why you got these findings!

Line 359-373: please try to focus on the main findings (reduce the conclusion section as possible).

Line 373: please highlight the limitations of this study if you have any.

In all tables, why the data were not presented as mean± sem in each group?

Author Response

We would like to thank the Reviewers for the very detailed comments to our manuscript, which greatly helped to improve our review. The resubmitted version of the paper was adjusted according to those suggestions.

The detailed reply to each of the comments is presented below, including the number of lines where it leads to a change in the paper. Also, each change was marked in red font in the revised manuscript.

This study aimed to assess the applicability of eleven different products of solid-state fermentation of rapeseed cakes with commercial enzyme additives on fermentation parameters and parameters of growth of a broiler experiment. The study is interesting and within the scope of the journal. I recommend acceptance of this manuscript after addressing the appended comments.

Line 28-29: the conclusion should be edited to represent the outcome of this study. Please address this point.

It was changed. Line: 27-31

Line 58: our previous studies instead of Our studies

It was improved.

Line 59: please add a brief on different exogenous enzyme preparations.

It was added: L: 56-59 “To best of our knowledge our studies provide the first reports on the effects of different exogenous enzyme preparations containing carbohydrases as α-amylase, β-xylanase or β-glucanase and/or phytase, on the chemical composition of the product obtained by natural solid-state fermentation of rapeseed cakes”.

Line 69: please refer to the parameters of “performance”.

It was added: (3) investigate the effect of different doses of raw or fermented rapeseed cake in diets on growth, feed intake and feed efficiency of broiler chickens. L:71

Line 70: a diagrammatic figure should be used to better explain the methodology. I recommend this, please.

It was added as Scheme 1.

Line 177: Please describe the statistical model well (mention the factors, levels, and tools).

It was added- L: 184-199.

Line 175-181: the authors should explain the measured parameters among the studied groups, the type of sampling, when the samples were extracted, and others.

It was explained in the methodology.

Line 234: these results should be highlighted in the methodology?

It was added in the methodology: During the experiment health of the birds was observed and mortalities and diseases noted. L:155-156.

Line 248: discussion section does not have subtitles. Please follow the guidelines of the journal for this issue.

It was improved.

Line 351-358: the authors should explain the findings of this study, rather than demonstrating similarities of finding with previous records or studies. Please explain why you got these findings! Line 359-373: please try to focus on the main findings (reduce the conclusion section as possible).Line 373: please highlight the limitations of this study if you have any.

Section discussion was rebuilt.

In all tables, why the data were not presented as mean± sem in each group?

The tables are elaborate. Presenting such detailed data in such extensive tables would make them illegible.

Sincerely,

Małgorzata Kasprowicz-Potocka

Reviewer 2 Report

This is an interesting topic for the poultry industry and address a way to improve the nutritional value of rapeseed for chickens. Below are my comments and suggestions to improve the content of the paper.

Introduction:

Line 54-55: how can you be so certain of it? Did you look hard enough? I suggest adding ‘to best of our knowledge.”

The knowledge gaps the study is not clear in the introduction. I suggest rewriting the introduction to provide the gap the study is trying to fill.

Material & Methods:

Line 75: it is unclear what a cake weight basis is. This description should allow anyone to repeat the study.

Lines 77-85: there are 11 treatment groups. I suggest putting then in bullet or in table to make it easy to read.

Line 97: Remove extra letter before protein. In addition, the methods by Hu (22), Haung (23), and Raney (25) could be briefly described in the manuscript.  

Statistical analysis:

Were the data analyzed as a factorial treatment arrangement? Please, clarify. It is mentioned that the significance was set at P < 0.05, but in the tables the authors differentiate p < 0.01 and 0.05. Please, revise.  

Results:

Overall, the results are poorly described. I suggest the authors revise the results section. Below are some of my comments. In addition, there are no description of the results comparing the different variants.

Line 187: I suggest replacing preparation by fermentation product to be precise.

Line 188-189: the authors stated that product 7 was characterized by the highest TP. I don’t think this is true based on the mean separation in table 5 because 7 shares same letter with 1,3,6,9,10, and 11.

Line 190-191: same as in line 188-189.

Line 200-203: I suggest presenting the differences instead of repeating the same values as in the table. Please, be consistent on how to present the results throughout the paper. 
Line 198-200: the level of maltose and maltotriose was … variant (1). What about variant 11?

Table 7: I suggest adding the FRC in another row to cover 1,2…11. So that the readers know that they are the fermentation variants.

Line 236: replace including by inclusion.

Table 8: this table is clustered and difficult to read. I suggest exploring another way to present it.

Line 247: is it a,b,c values in the same row or column?
I don’t see much about the results related to production performance presented in table 8.

I suggest describing these results by period 1-9, 10-19, 20-35, 1-9d, or if the authors choose to use starter, grower, finisher (see lines 236-238), this has to be defined in the footnote of the table to help the reader.

Line 240-241: There is type by dose interaction for FCR. The authors need to describe this interaction for the reader.

Line 140-142: the authors chose the variant 8 for broiler experiment: Was the selection based on the results of the analyses of the fermentation products? What is the rationale for selecting the variant 8 instead of other variants with similar results (see your tables 5, 6, 7, and 8)? Please, clarify.  

Discussion:

Lines 263-68: this is the first time the authors mentioned results comparing the different variants and this should have been described in the results section.

Line 262-334: this is a single and long paragraph on the fermentation products. I suggest revising into 2, 3, or 4 paragraphs with better flow (for example, separate the discussion points on the basic composition including phytate, crude protein, glucosinolates, carbohydrate etc.). In the current state, the discussion just mixed all the above points jumping from one point to another.

Line 329: there is nothing in the previous paragraphs that leads to this summary about variant 8. Please, revise the discussion accordingly.

Line 367: the most …exogenous-6-phytase. I think this conclusion is not based on the any described results in the paper. Unless you clearly show why this variant was yield the most desirable results.

Line 371: there was no digestibility experiment done in the current study. therefore, I suggest limiting the conclusion on growth parameters instead and remove feed utilization.

Author Response

We would like to thank the Reviewers for the very detailed comments to our manuscript, which greatly helped to improve our review. The resubmitted version of the paper was adjusted according to those suggestions.

The detailed reply to each of the comments is presented below, including the number of lines where it leads to a change in the paper. Also, each change was marked in red font in the revised manuscript.

This is an interesting topic for the poultry industry and address a way to improve the nutritional value of rapeseed for chickens. Below are my comments and suggestions to improve the content of the paper.

Introduction:

Line 54-55: how can you be so certain of it? Did you look hard enough? I suggest adding ‘to best of our knowledge.”

It was changed. L: 56

The knowledge gaps the study is not clear in the introduction. I suggest rewriting the introduction to provide the gap the study is trying to fill.

Introduction was rewritten.

 Material & Methods:

Line 75: it is unclear what a cake weight basis is. This description should allow anyone to repeat the study.

It was added in Scheme 1.

Lines 77-85: there are 11 treatment groups. I suggest putting then in bullet or in table to make it easy to read.

It was done as table 1.

Line 97: Remove extra letter before protein.

It was done.

In addition, the methods by Hu (22), Haung (23), and Raney (25) could be briefly described in the manuscript

Authors briefly described three advisable methodology (L: 91-98 and 118-122).

Statistical analysis:

Were the data analyzed as a factorial treatment arrangement? Please, clarify. It is mentioned that the significance was set at P < 0.05, but in the tables the authors differentiate p < 0.01 and 0.05. Please, revise. 

Thank you for your comments. It was revised. L: 187-188.

Results:

Overall, the results are poorly described. I suggest the authors revise the results section. Below are some of my comments. In addition, there are no description of the results comparing the different variants.

It was changed according to Reviewer comments.

Line 187: I suggest replacing preparation by fermentation product to be precise.

It was changed.

Line 188-189: the authors stated that product 7 was characterized by the highest TP. I don’t think this is true based on the mean separation in table 5 because 7 shares same letter with 1,3,6,9,10, and 11. Line 190-191: same as in line 188-189. Line 200-203: I suggest presenting the differences instead of repeating the same values as in the table. Please, be consistent on how to present the results throughout the paper.

All these suggestions were realized. L: 204-234

Line 198-200: the level of maltose and maltotriose was … variant (1). What about variant 11?

It was added.

Table 7: I suggest adding the FRC in another row to cover 1,2…11. So that the readers know that they are the fermentation variants.

It was added.

Line 236: replace including by inclusion.

It was changed.

Table 8: this table is clustered and difficult to read. I suggest exploring another way to present it. Line 247: is it a,b,c values in the same row or column?

The table has been converted to make it easier to read the data.

I don’t see much about the results related to production performance presented in table 8. I suggest describing these results by period 1-9, 10-19, 20-35, 1-9d, or if the authors choose to use starter, grower, finisher (see lines 236-238), this has to be defined in the footnote of the table to help the reader. Line 240-241: There is type by dose interaction for FCR. The authors need to describe this interaction for the reader.

It was change and added. L: 257-258 and table 9.

Line 140-142: the authors chose the variant 8 for broiler experiment: Was the selection based on the results of the analyses of the fermentation products? What is the rationale for selecting the variant 8 instead of other variants with similar results (see your tables 5, 6, 7, and 8)? Please, clarify. 

It was added: The fermented rapeseed cakes (variant 8) obtained using liquid exogenous-6-phytase (5000 OUT/g, Huvepharma N.V., Belgium) expressed in Pichia pastoris was selected for the experiment on broilers based on the results of the chemical analyses of the fermentation products, ease of application and price of additive. L146-149 (Furter explanations were added in the other manuscript sections).

Discussion:

Lines 263-68: this is the first time the authors mentioned results comparing the different variants and this should have been described in the results section.

It was done.

Line 262-334: this is a single and long paragraph on the fermentation products. I suggest revising into 2, 3, or 4 paragraphs with better flow (for example, separate the discussion points on the basic composition including phytate, crude protein, glucosinolates, carbohydrate etc.). In the current state, the discussion just mixed all the above points jumping from one point to another. Line 329: there is nothing in the previous paragraphs that leads to this summary about variant 8. Please, revise the discussion accordingly.

Discussion was rebuilt.

Line 367: the most …exogenous-6-phytase. I think this conclusion is not based on the any described results in the paper. Unless you clearly show why this variant was yield the most desirable results.

It was improved. L: 371-385

Line 371: there was no digestibility experiment done in the current study. therefore, I suggest limiting the conclusion on growth parameters instead and remove feed utilization.

It was changed. L: 408-416.

Sincerely,

Małgorzata Kasprowicz-Potocka

Round 2

Reviewer 1 Report

In all tables, why the data were not presented as mean± sem in each group?

Author Response

Tables 1-4 do not require prior disclosure of data with deviations. Due to the large number of preparations in Tables 5-8 and the complex statistics in Table 9, introducing deviations would significantly reduce the readability of the data.

Reviewer 2 Report

Line 59: replace solid-state fermentation by SSF.

Line 149: replace calculated by formulated.

Line 209: than product 4 and 5.

Line 219: Define DGG.

Table 9: Correct 155c by removing the superscript.

Line 410: replace “from 12 to 22%” by 12 and 12%, because the study only tested these inclusion levels.

Author Response

All changes were made in accordance with the reviewer's recommendations.