Evaluation of the Addition of Humicola Grisea Cellulase to Broiler Chicken Rations for a 21-Day Period
, Cirano José Ulhoa 2, Weslane Justina da Silva 2, Denise Russi Rodrigues 3, Nadielli Pereira Bonifácio 1, Fabiana Ramos dos Santos 1, Fabiano Guimarães Silva 1 and Cibele Silva Minafra 1,*
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsRegarding the manuscript entitled Evaluation of the addition of Humicola grisea cellulase to broiler chicken rations for a 21-day period
Why the authors used these doses, on which basis? Since they did not find any significant findings.
L78. Add hypothesis.
Add subheadings to the materials and methods section.
L137. Why did the authors not analyze crude fiber digestibility since they added enzymes?
For tables add actual p values
Discussion, combine short paragraphs. As well as add the possible mechanism of action and conceptualization.
Comments on the Quality of English Languagemoderate revision
Author Response
I would like to thank the reviewer for his care and attention in evaluating the manuscript and for dedicating his time. I believe that all criticism is constructive to make the article more valued and meet the demands of the renowned magazine. I have tried to address all concerns appropriately and I believe the article has improved considerably.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsIn the introduction, better explore the tested product. Is it an established commercial enzyme? What characteristics of the enzyme led to its choice for use in a corn and soybean meal diet? Is there a variation from the enzyme produced and tested in the experiment to others on the market? What is the mode of action of this enzyme?
How were cellulase levels defined? 1,000/ton, if we consider the average feed intake at this level (55g/bird/day) each animal would be intake around 211 U of cellulase. Is this amount enough? What value of cellulose and PNAS of the diets?
The digestibility test has not been described sufficiently. Was it by the total collection method? How did they do 4-7 day digestibility without taking into account the yolk sac that is still being absorbed? It was described that fat analysis would be done in the digestibility test, but no results were presented. How to work with cellulase and not evaluate the metabolizable energy of the diets, since the digestibility test was carried out? What is the function of cellulase then? Another confusing analysis was nitrogen retention in the stool, what's the point? How was it calculated? What is the difference between nitrogen excreted and nitrogen retained in feces? Why the numbers don't add up... Nitrogen retention in the body is usually calculated and not in the feces. Nitrogen digestibility values do not match the presented data, for example from 14 to 17d: ND= (66.42-18.64)/ 66.42*100)=71.93% and not 90.18%.
The description in table 2 mentions the results in two phases, but three were presented in isolation. As an analysis of covariance was not performed, the ideal is to present data from 1-7d, 1-14d and 1-21d.
The topic of discussion should be to discuss the results of the experiment and not repeat that other works have not found an effect.
The discussion was unsatisfactory on several points. In table 3, in which the N digestibility data worsened with the addition of the enzyme, the discussion was “softened”, with the information that the N digestibility did not improve, attributing this fact to the age of the birds. If that were true, no statistics would have been shown and the relative weight of the large intestine would not have increased with the inclusion of the enzyme as well.
Nor was the increase in the relative weight of the large intestine discussed, which would be precisely the main focus of the work. Obviously, the enzyme had an effect in some way, providing greater release of indigestible oligosaccharides for fermentation in the large intestine, probably not acting in the total breakdown of cellulose. But anyway, the authors preferred to create other theories, instead of discussing probable mechanisms of action of the enzyme and how it exerted the effects observed in the work.
On lines 282 to 289, the text is quite confusing. Because initially it says that amylase is not specific to birds, and which enzyme would be specific? Line 288 describes a result that is not true, as it had no statistical effect on pancreas weight and amylase activity and the proportional weight of the pancreas was not shown in the table, but the absolute weight, therefore there is no way to make such a statement.
Other parts of the discussion are looking for metabolic problems that could cause some change in the evaluated parameters, but there was no challenge in the experiment to proportionate such changes, the values of cellulose or polysaccharides in the diets were not even included. In this way, the authors are discussing other works (lines 297 to 328).
The description of some basic parameters is also poorly translated, such as ration consumption, which should be the most common feed intake.
Author Response
I would like to thank the reviewer for his care and attention in evaluating the manuscript and for dedicating his time. I believe that all criticism is constructive to make the article more valued and meet the demands of the renowned magazine. I have tried to address all concerns appropriately and I believe the article has improved considerably.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsDear authors
I hope all of you are always fine. Regarding the revision of the manuscript No. poultry-2568550, titled “Evaluation of the addition of Humicola grisea cellulase to broiler chicken rations for a 21-day period”. Really it is an interesting research, however, some comments should be replied.
Comments
1- Comparison of Humicola grisea cellulase with other cellulase (e.g. bacterial source) was very essential?
2- Superscripts indicating the significant difference should be added on the values of all tables.
3- How could you mix the amount of cellulase as 500 ml/t and 1,000 ml/t?
4- In the results, it would be better to change some tables into figures.
5- Humicola grisea should be written in italic form (Humicola grisea).
6- Line 88 and 145: replace pen by cage.
7- Table 5 and 6: please correct G to g.
Author Response
I would like to thank the reviewer for his care and attention in evaluating the manuscript and for dedicating his time. I believe that all criticism is constructive to make the article more valued and meet the demands of the renowned magazine. I have tried to address all concerns appropriately and I believe the article has improved considerably.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsDear authors
Thank you for your revisions
Comments on the Quality of English LanguageMinor editing
Author Response
Dear reviewer, we are grateful for your response and your contribution to the study.
Reviewer 2 Report
Comments and Suggestions for Authors
Some justifications presented were understood and others still need to be improved.
Please adjust the title of table 3
Insert in the title, variable included in the body of the table (DDMC%) and the evaluated ages of the animals (14 to 17d also)
Another justification that was not scientifically based was in relation to nitrogen retention, as the method of determination can be based on nitrogen in the carcass and not on weight gain as justified by the authors. In other words, to calculate retention, the composition of the carcass should have been analyzed, and the g of nitrogen retained in relation to N consumption should have been measured. Another method of calculation, and the most used, is by the nitrogen balance in relation to the nitrogen intake, which would be similar to the digestibility value. But as it is a chemical element, digestibility is generally used when it is protein (% Protein digestibility), and retention when it is nitrogen (Nitrogen Retention). Therefore, the nitrogen retention data presented does not match the retention for most scientific works. See an example of work describing the calculation of retained nitrogen (doi.org/10.1071/AN16687). Review the name or remove the data from the table.
The nitrogen digestibility values still do not match the data presented, for example from 14 to 17d BD diet: ND%= (66.42-18.64)/ 66.42*100)=71.93% and not 90 .18%. Reevaluate the calculations.
Author Response
Dear reviewer, we are grateful for your response and your contribution to the study.
Author Response File: Author Response.pdf
