Comparisons of Ramie and Corn Stover Silages: Effects on Chewing Activity, Rumen Fermentation, Microbiota and Methane Emissions in Goats

Round 1

Reviewer 1 Report

In my opinion, the article provides new data and information about the ramie of which there is little information. However, a major revision is necessary to provide more concise information and to justify issues that are not clear.

I am sending two documents for the authors:

1-PDF of the manuscript with comments and yellow underlining.

2-Comments for authors.

Authors will find the comments identified with the line and in the PDF they will see in yellow which part of the text the comment refers to.

In general, the introduction should include more concise and specific information on the characteristics of this forage in ruminant feed.

There is a lack of relevant information in the material and methods. Such information would be necessary to know the reason for certain results.

How was the in vitro fermentation carried out? How were the silos made? pH, days of silage, organoleptic characteristics?

The results can be improved, and more relevant information can be included.

Add graphs of degradation kinetics as suggested, add analysis of secondary compounds, add ratio calculations to assess methane emission.

The discussion is very brief, it deals with general and already known things. There is a lack of depth in discussing why the results are like this. There are results that are overlooked and not discussed. On the other hand, results are justified on the basis of assumptions (e.g. the reduction of methane due to condensed tannins, but these tannins have not been analysed).

The conclusion should be adjusted to the objective.

Comments and suggestions to the authors are available (underlined with yellow) in the attached pdf file

Line 17: Indicate the scientific name of ramie

L 20: I am confused. It seems that 60% of the total silage is replaced. Actually about 45% of ramie is included (see table 2).

So I would say: The ramie silage diet was formulated by replacing of 60% CS with ramie silage, including a 45% of ramie silage in the final ramie silage diet.

At many points in the manuscript, it appears that 60 % of ramie silage is included.

L 29: what is “idling activity”: Explain, plis.

L55: On dry matter?

L55: How many tonnes/hectares per year?

L56: 67% of alfalfa is replaced with ramie? Why do you write "with < ramie silage? what does that mean <?

L62. the analysis of secondary compounds (condensed tannins, polyphenols) should be carried out. You indicate in the introduction that methane reduction may be due to these secondary compounds, but you do not analyse them in the present study.

L77: What were the final conditions of both silos? ph, odour, colour ....

L78: What does this mean?

L85: How many days did the silage of each forage last?

Were the two forages silaged for the same number of days?

L85-86: The silos were open for 3 weeks, why?

How did the chemical composition evolve in those 3 weeks?

L92: 1 or 10 g? In which article have you seen that 1 g of substrate is added to 60 ml of liquid?

L95: In this article. I can't find the fermentation conditions, rumen liquid/artificial saliva ratio, etc. .... Please describe how the in vitro fermentation was carried out.

L96: Was degradation completed within 48 h?

Could you present a graph with the degradation kinetics. Similar to figures 1 and 2 of Rufino et al., 2019. "Effect of the method of preservation on the chemical composition and in vitro fermentation characteristics in two legumes rich in condensed tannins"

L104: How many runs?

L105: Do you use a different rumen fluid donor every day? Characteristics of the donor animals: weight, age, feed, sex…

L 112: Was the diet formulated according to maintenance needs?

Table 2: Diet by DITE

L 151: How was the rumen liquid obtained?

Cannulated animals?

Orally with a tube?

L 189: Correct to Van Soest

L 189: Include ash in Tables 1 and 2

Table 4: What methodology and how did you calculate the degradation of the substrates? Not described in Material and Methods

Table 4: It does not fall under the heading substrate degradation. Place on top of Molar percentage of individual VFA. Correct

Table 4: It would be interesting to know the ratio of methane to total gas produced or Total VFA.

CH4/gas (mL/L)

CH4/VFAtotal (mL/mmol)

L202: Because at 0, 2.5 and 6 H. What is the criterion? Bibliography?

L231: Correct. CS had more hydrogen than ramie (721 vs 522 uL/g OM degraded).

L238: GE intake is not in table 5

L 281: What is the reason for the increased production of VFA in CS?

Was ramie degration complete?

L282-284: how do you relate the percentage of propionic acid to methane production?

L283: It contains less H2 volume than CS (522 vs. 721, respectively) according to table 4.

L 284: Can you prove it with your study? In Table 7, there is no effect of diet on Methanogens.

L286: Enter the ash content in tables 1 and 2.

As ramie has secondary compounds, could this have an influence?

Analyse condensed tannins

L289. Discuss why if there is lower digestibility there is higher production of total VFA in ramie.

L293: Can ramie contain any anti-nutritional factors?

L285-293. Discuss methane emission results

L297-300: this information is interesting, it could be developed in the introduction and explain some of the results of in vitro and in vivo fermentation.

L335: These analyses are necessary

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

ID: Fermentation 1801240

Title: Comparisons of ramie and corn stover silages: effects on chewing activity, rumen fermentation and methane emissions in goats.

The authors give a comprehensive overview of the experiment and keep to previous theories. However, I encountered several errors such as in the results section. It is important to thoroughly review the authors. For instance, only one factor (diet) is frequently shown in Table 7. The time-related issue should not be ignored by the author. Further explanation is required if the author has any future plans to provide a solution to the ramie limitation because the experiment's conclusions are ambiguous and should be suggested to individuals interested in further testing. I am hopeful that the authors will be able to answer the questions I have posed in this manuscript.

Title:

Use capital letters in the title as “Comparisons of Ramie and Corn Stover Silages: Effects on Chewing Activity, Rumen Fermentation and Methane Emissions in Goats.”

Abstract

General

The authors report a few experimental findings erroneously. Please update the text in the abstract if the author has made changes based on my advice.

Introduction

Specific

Line 53-62: I advise using "less than" or any other term that brings the sentence to a close instead of the “<”.

Materials and method

General

Can Ramie fully take the role of CS? Why did the author decide to replace some parts? Please respond to the inquiries and provide clarification in the manuscript.

Specific

Section 2.3: Will this experiment be biased by the difference in crude protein content between the ramie (15.2%) and corn (14.5%) formulas? Does this variation have an impact on how bacteria develop in the rumen of sheep? Describe in detail, please.

Results

General

The interactions shown in Table 7 occurred. If there was an interaction between the two factors, the authors were unable to provide only one factor.

Specific

Line 231: It is untrue that the author claims that Ramie produces more H2 than CS does. Please review and make the necessary corrections.

Line 238: The author does not show the GE intake values ​​in the table, but there are in this line. Please add more to match the in-line description.

Line 242: Also added CH4 as g/kg DM digested emission data.

Line 251: There is no statistically significant difference when eating activity is reported as number/d, hence the author's description on this line is incorrect.

Line 252: Does the non-nutritive oral activity expressed as min/d have a p-value less than 0.05? If not, then no statistical difference please remove it.

Line 259: What is the displayed p-value of 0.006? Why does it not match in the table? And the interaction between the factors led the authors to look at the factor between diet and time, unable to address diet specific.

Line 260-263: Enhance how the experimental results are presented. The authors should also discuss the effects of time.

Line 263-264: I disagree with the statement “The time of sampling had a significant effect (p > 0.05) on most parameters” because 9 out of 11 parameters presented by the authors were statistically significant, p<0.05.

Line 267: dH2 did not show any differences in interaction.

Line 308: Please discuss more why high forage content in diets could maintain pH?

Line 310-311: It is more appealing to give more information and include citations that are relevant, such as “The rumen microbiota primarily creates volatile fatty acids during the fermentation of carbohydrates (Kang et al., 2012). In fact, the synthesis of volatile fatty acids (VFA) by rumen microbes can meet up to 70% of a ruminant's energy requirements (Wachirapakorn et al., 2016).” See citation at doi:10.1016/j.anifeedsci.2012.03.007 and doi:10.1016/j.aninu.2016.08.007

Line 352: “Such reduction in CH4 production might be caused by the decreased activities of methanogens” Whether decreased activities of methanogens or decreased population of methanogens? Clarify.

Conclusion

General

Ramie reduces the amount of CH4 that animals produce but at the sacrifice of lower TVFA yields and digestibility. How does this compensation meet the level of corporate output? The authors should provide a weightier justification to certify the results of the experiment and should show that ramie should really be a substitute for CS? or is there a need for further improvements or techniques in the future? Please advise those interested in continuing the trial from you.

Specific

Line 356 and 359: Use words that begin with “Although” in successive sentences. I think inappropriate should improve the new sentence

Table

-The P-value is shown in the table I think shows significantly, that P<0.01 should be sufficient.

-Table 1: superscript numerals in order for different chemical compositions It is recommended to utilize different numbers, such as DM¹, OM², CP³, etc.

-Table 2: Why doesn't the author explain the chemical composition using a superscript like Table 1? I advised using the same writing style when completing this manuscript.

-Table 4: Why Total VFA is reported in the substrate degradation section, the author should move to the VFA reporting section.

Author Response

Please see the attachmen.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Manuscript ID: fermentation-1801240

Comparisons of Ramie and Corn Stover Silages: Effects on Chewing Activity, Rumen Fermentation, Microbiota and Methane Emissions in Goats

Even manuscript has been improved, there are required a minor revision remain.

L36-39: Too hard to understand and long sentence, please re-write.

L82-82: Change to “Ramie silage (B. Nivea "Zhongzhu No.1") and CS silage were obtained from Hunan Deren Animal Husbandry Technology Co. Ltd.”

Table 1: change the title to “Table 1. Ingredients and chemical composition of corn stover (CS) silage or ramie silage”

Table 2: The authors should discuss more regarding the difference between some ingredients such as urea (11 vs 0 g/kg) which may influence rumen fermentation and ammonia-N etc.

L335-336: Provide biological mechanisms to support.

L392: Provide a mechanism for how tannin influences CH4.

Author Response

Please see the attachment

Author Response File: Author Response.docx