Granulated Cane Sugar as a Partial Replacement for Steam-Flaked Corn in Diets for Feedlot Cattle: Ruminal Fermentation and Microbial Protein Synthesis

Round 1

Reviewer 1 Report

Dear authors,

It was my great pleasure to read and review this manuscript which is excellent in every sense. The article is written concisely, with perfect English language. Please find my suggestions in Word document that I think would improve this manuscript.

Comments for author File: Comments.pdf

Author Response

Responses to Reviewer 1

We are grateful to reviewers for the time and effort in helping improve the quality of the manuscript. The observations were wise and timely which permit the improvement substantially the manuscript. We have addressed the concerns in our revised manuscript accordingly.

All changes and correction made are highlighted in yellow in the corrected version of the manuscript.

Dear authors,

RW: It was my great pleasure to read and review this manuscript which is excellent in every sense. The article is written concisely, with perfect English language.

AU: Thanks. We really appreciate your kind opinion.

 

RW: Here are my suggestions that I think would improve this manuscript:

RW: ABSTRACT:

RW: I suggest that you add one or two sentences at the beginning like an introduction for your study. Currently you start with material and methods.

AU: A introductory sentence was inserted as is suggested

DISCUSSION:

RW: I suggest that you finish discussion with some general conclusions that are based on everything stated above. Here you can add what is the maximum inclusion level of GCS according to your results and also some short explanation why not more. Also, add ideas for future research and explanation why is that so.

AU: Followed your suggestion we included the points mentioned.

RW: CONCLUSION: “Accordingly, a greater benefit to supplementation is expected in light-weight calves during the early growing phase when metabolizable protein is most likely to be deficient.” In Conclusion you should comment only results obtained in present study. Therefore, this sentence should be moved to Discussion.

AU: The sentence was moves as suggested. Thanks!

RW: Please find below my comments relating to specific lines:

RW: Line 50: “increasing level dried shredded” – add OF between level and dried;

AU: Because some parts of Introduction was rewritten this observation no longer applies.

RW: Line 51: SFC – please add full description of abbreviation (it is added in abstract but not in main text)

AU: Done

RW: Line 52: “growing finishing” – add AND between

AU: Because some parts of Introduction was rewritten this observation no longer has to be modified

RW: Line 57: “steam-flaked corn” – use abbreviation instead

AU: Abbreviation was used as suggested

RW: Line 65: GCS is already used in text so no need to write full description

AU: Correction was made

RW: Line 71: use abbreviation SFC

AU: Correction was made

RW: Line 72: “replacement SFC” – add FOR between

AU: Correction was made

RW: Table 1: first row – add GRANULATED before Cane

AU: Correction was made

RW: Line 76: use the same unit for Chromic oxide as in table

AU: Correction was made

RW: Line 80: what is Control diet? Diet with 0% GCS? Please add this to avoid confusion

AU: Clarification made to avoid confusion

RW: Line 102: replace word “analysis” with plural form

AU: Correction was made

RW: Line 105: add space between 1 and mL

AU: AU: Correction was made

RW: Line 135: “Analysis performed” – add WAS between

AU: AU: Correction was made

Reviewer 2 Report

Rumen fermentation, microbial protein synthesis, and N efficiency as affected but steam-flaked corn replaced by granulated cane sugar was investigated in 4x4 LS design by using rumen and duodenum cannulated steers.

The big point is that CP content in diet was huge different, T1 was 14.93% while T4 was only 11.13%, nearly 5% different.This might impact NH3 availability in the rumen as well as microbial activity, resulted in yield or concentration of fermentation end-products as well as microbial protein synthesis which is main objective of present work.Therefore, the author have to declare effect of GCS replacement for SFC out from effect of CP levels in diet, by using statistical analysis. Accordingly, result and discussion on effect of CP levels in diet must include in the manuscript.

Introduction:

- Could review and mention about effect of rapidly rumen degradable CHO like sugar on ruminal pH which is highly impact on feed digestion by rumen microbe and also microbial growth

M&M:

- Practicing with rumen and duodenum cannulated steer need to put more detail, how to use anesthetic, surgery, remedy, etc. to declare the animal ethics and welfare

- Methods used to separate feed particle and microbial cell, separate feed N and microbial N, also purine from microbial cell or feed must be well detail, referring to previous work may be not clear (Bergen et al., 1968; Zinn et al., 1986)

Result:

- Ruminal pH lower than 6.00 may be face acidosis, did the author found this incident and how?

Comments for author File: Comments.pdf

Author Response

Response to Reviewer 2

We are grateful to reviewers for the time and effort in helping improve the quality of the manuscript. The observations were wise and timely which permit the improvement substantially the manuscript. We have addressed the concerns in our revised manuscript accordingly.

All changes and correction made are highlighted in yellow in the corrected version of the manuscript.

RW: Rumen fermentation, microbial protein synthesis, and N efficiency as affected but steam-flaked corn replaced by granulated cane sugar was investigated in 4x4 LS design by using rumen and duodenum cannulated steers.

RW: The big point is that CP content in diet was huge different, T1 was 14.93% while T4 was only 11.13%, nearly 5% different. This might impact NH3 availability in the rumen as well as microbial activity, resulted in yield or concentration of fermentation end-products as well as microbial protein synthesis which is main objective of present work.

AU: The main objective was determined the effect of directly replacing steam flaked corn with sugar. Because of compositional differences between GS and corn we expected corresponding difference in diet composition (mainly CP and NDF) and in digestion and VFA patterns, this clarification was included in the corrected manuscript as suggested.  Even so, all dietary treatments exceeded CP requirement for ruminal microbial growth.

RW: Therefore, the authors have to declare effect of GCS replacement for SFC out from effect of CP levels in diet, by using statistical analysis. Accordingly, result and discussion on effect of CP levels in diet must include in the manuscript.

AU: Clarification included as suggested

Introduction:

RW: Could review and mention about effect of rapidly rumen degradable CHO like sugar on ruminal pH which is highly impact on feed digestion by rumen microbe and also microbial growth

AU: Done as suggested

M&M:

RW: Practicing with rumen and duodenum cannulated steer need to put more detail, how to use anesthetic, surgery, remedy, etc. to declare the animal ethics and welfare

AU: Description was made as suggested

RW: Methods used to separate feed particle and microbial cell, separate feed N and microbial N, also purine from microbial cell or feed must be well detail, referring to previous work may be not clear (Bergen et al., 1968; Zinn et al., 1986)

AU: Procedure were described as suggested

Result:

RW: Ruminal pH lower than 6.00 may be face acidosis, did the author found this incident and how?

AU: The ruminal pH was determined, as indicated in document, 4-h post-feeding. We didn’t measure ruminal pH at different intervals (i.e. hourly) thus we don’t have information about of how many hours during the day ruminal pH was maintained below 5.5, but clearly, 40% sugar appears to put cattle at risk. Nevertheless, we didn’t observe symptoms of acidosis (off feed, diarrhea) in any steers during the experimental period.

 

Reviewer 3 Report

This manuscript has scientific value and is very well done and analyzed.

Beyond considering it worthy of publication, I allow myself to leave a suggestion:

Although work was done respecting the same energy load, the same was not done with the intake of crude protein, which could have been done by adjusting the differential intake of urea, which, however, was the same for each diet.

Considering the above, I believe that the difference in crude protein is an aspect that differentiates the diets, which could have an effect on the parameters evaluated, for which I suggest adding your opinions to the discussion.

Author Response

Response to Editor

We are grateful to reviewers for the time and effort in helping improve the quality of the manuscript. The observations were wise and timely which permit the improvement substantially the manuscript. We have addressed the concerns in our revised manuscript accordingly.

All changes and correction made are highlighted in yellow in the corrected version of the manuscript.

ED: Title is too long, please shorter.

AU: Title was shortened as suggested

ED: Please define when first refer! Also, check for all abbreviation.

AU: All abbreviations were defined, checked and corrected here and through the whole manuscript.

ED: The conclusion should be related to the title and objective. It seems to be lack of rumen fermentation...etc.

AU: Conclusion was rewritten as suggested

ED: Introduction is too weak and insufficient literature review. Here, only 10 citations were referred. Suggest the authors review more and add relevance citation as well as define clear what are the research gap when compare to the previous study.

AU: There is no published data that we are aware of evaluating the use of sugar as a substitute for corn in diets for feedlot cattle. Even so, the introduction was rewritten to amplify and strengthen as suggested.

ED: Please review more why the authors focus on feedlot cattle.

AU: No information available regarding effects of sugar supplementation in finishing diets for feedlot cattle.

ED: Please add location of study in this section since the affiliation of corresponding authors differ to the Animal Ethic Committee.

AU: Done

ED: It should be "Granulated cane sugar level"...check all tables

AU: Correction was made as suggested.

ED: Please define NDF!

AU: The abbreviation was defined as suggested.

ED: change to control

AU: Done

ED: check the “Discussion” position

AU” Correction was made.

ED: The conclusion should be related to the title and objective. It seems to be lack of rumen fermentation...etc.

AU: Conclusion was rewritten according to the suggested recommendation.

ED: Not clear! Are the authors evaluated economy?

AU: No, the term was changed as “N efficiency”