Effects of Administration of Prebiotics Alone or in Combination with Probiotics on In Vitro Fermentation Kinetics, Malodor Compound Emission and Microbial Community Structure in Swine

Round 1

Reviewer 1 Report

This paper used an in-vitro fermentation model of the swine gut to investigate the effect of Lactobacillus amylovorus, L. plantarum, galacto-oligosaccharide (GOS) and their synbiotic formulations on pH, volatile fatty acids (VFA), malodor, and microbial ecological profiles through a 24 hour-incubation, but the author still has many problems with the description of the results, the logical level of the article, summarized as follows :

Point 1: Check writing criterion of articles. For example: L59, Figure 1, Table 1.

Point 2: This article contains less recent references. The research is unlikely to be novel to such an extent.

Introduction

Point 3: The main concern in the first paragraph is to explain the importance of fermentation in the digestive system of monogastric animals or to describe why the method of in vitro fermentation is used? 

Point 4: L66-68: What is the relationship with the previous content of this paragraph? What problems do you want to explain?

Point 5: Why it is important to study these two types of lactobacilli is not adequately described in the introduction.

Point 6: This experiment focuses on malodorous gases, but the introduction does not describe the significance of studying them.

Point 7: L69-70: The authors describe 'Understanding the fermentation profiles of feed in the large intestine is essential for feed evaluation and gaining insights into the microbial influence on fermentation.' But why focus on the effects of synbiotics on fermentation and microbial dynamics in the large intestine exists?

Materials and Methods

Point 8: In 2.1: What is the nutrient level of the fermentation substrate?

Point 9: provided information list as the experimental design,  sampling, testing and other steps. 

Point 10: L102: How did authors conclude that the animals were healthy? Additional information is required to determine the validity of the experimental design. for example the nutrients content of diet  provided.

Point 11: In 2.3: How many replicates per treatment?

Point 12: Before collecting the sample after the cultivation, is the fermentation terminated? How to terminate the fermentation?

Point 13: Is sample testing performed immediately after the experiment or are the samples saved for later testing? If saved, under what conditions are the samples stored?

Results

Point 14: In 3.1: The composition of additives, should it be placed at the materials and methods section.

Point 15: According to the pH results in Table 1, there was a highly significant difference between the treatment groups at 0h, why in the description the authors concluded that "The pH concentration of the in vitro fermenter was consistent in all the treatments at 0 hours of incubation".

Point 16: L239-240: The data displayed could not intuitively reflect that a proportional increase in the total gas production with time, and the T5 treatment decreased instead.

Point 17: L241: According to the  results, the highest total gas production was observed in the 24 h of T3 treatment group, which is not consistent with the authors' description.

Point 18: Figure 1,2 and Table 1,2  have the problem of repeated data display.

Point 19: All the detection indicators should be clearly expressed in the materials and methods. For example, Ammonia was detected in Table S1, but not described.

Point 20: Lack of alpha analysis between different treatment groups.

Point 21: In Figure 4,  modify the principal components to be shown with PC1, PC2.

Point 22: What is the meaning of the Figure 6 and S1? There is no description in the results.

Discussion

Point 23: L382 and L386-388: The same meaning was repeatedly expressed.

Point 24:  the conclusions should be concise.

 

can be improved.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Reviewer 2 Report

Review fermentation-2476503

Manuscript-2476503-submitted by Jaeyoung Heo et al. evaluates the potential of Lactobacillus amylovorus, L. plantarum, galacto-oligosaccharide (GOS) and their synbiotic formulations on pH, volatile fatty acids (VFA), malodor, and microbial ecological profiles after 24-hour of incubation.

The authors concluded that administeration of prebiotics alone or combination with probiotic positively shifted microbial structure and composition and increased volatile fatty acids yield while reduced the excretion of all odorous compounds except ammonia. Generally, a well written manuscript, relevant and for me it is interesting and important for the field. However, the English needs to be revised to improve the quality of the manuscript. I think that this manuscript could be accepted after some modifications. I will only highlight some general comments:

Title:

- I suggest rewrite the title for being for example: Effects of administeration of prebiotics alone or combination with probiotic on in vitro fermentation kinetics, malodor compounds emission and microbial community structure in swine.

Abstract

- I would recommend to delete: Here we use an in-vitro fermentation model of the swine gut to.. and start with: The objective of this study was to investigate…….

- The abstract conclusion requires to be clear; I suggest to rewritten.

Introduction:

I have some general comments:

- The introduction of manuscript is diluted and semi adequate in respect to reviewing the latest literature relative to the study described and should be improved somewhat.

- Please emphasis on the added value/novelty of this review article as there are plenty of article utilizing prebiotics and probiotic in the literature. Please provide more recent literature reviews and citations that can be related to the forms and way of application. I would add a few sentences explaining what additional information your study will bring. Can you confirm this with more recent references?

- The hypothesis is not clear; I suggest to double check it again. I would add a few sentences explaining what additional information your study will bring. As it is, it seems that your experiment is demonstrating something that has already been shown.

Materials and methods

Seems well written.

Results:

- The results section needs to be shortened with emphasis on important findings.

- I suggest omitting all sentences with is no significant effect observed.

Discussion:

- I would suggest making every effort to explain more the results and not compare them with other studies. In general, the production data are interesting but did not discussed well.

- The discussion should include further arguments between studies or results found in the literature.

Conclusion: - Conclusion section is too short. Therfore, the general idea need to be revised and make it clear in addition avoid the repetition of what you have already written previously.

References

- I suggest reducing the total number using the most recent references following the journal style.

English needs to be revised to improve the quality of the manuscript

Author Response

Please see attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

English need to be revised

English need to be revised