In Vitro Rumen Fermentation Kinetics Determination and Nutritional Evaluation of Several Non-Conventional Plants with Potential for Ruminant Feeding
Round 1
Reviewer 1 Report
Review, paper no. fermentation-2331474 entitle „In vitro rumen fermentation kinetics, determination, and nutritional evaluation of several non-conventional plants, with potential for ruminant feeding”. This is an important area for improving cattle production. This is a well-organized study, with sufficient methodology and adequate description of the results. The manuscript idea is somehow new with great interest The authors have used the standard journal format in manuscript writing. The manuscript contains several inaccuracies in methodology. Generally, the article has some interesting findings which could be worth publication.
Specific comments:
Overall it is still quite well written although the „Conclusions” could be more clearer.
Simple Summary: Correct.
Abstract: Is sufficiently presented (methods, results, general conclusions).
Introduction: The introduction section is sufficient and analytically and adequately covers the need for the study.
Line 62. Please add research hypotheses.
Materials and Methods: The methodology is sufficiently presented. However, it has a few inaccuracies.
Line 78. Why these plants were chosen?
Line 95. What in vitro system was used for incubation. Was it a commercial system
Line 104. The method for determining gas production at time points shall be detailed.
Results:
Line 230. Table 1 should be Table 7
Table 7. write 0. …
Discussion:
Could authors define possible limitations of the study?
Conclusion:
Clearly indicate the direction of changes in the tested parameters. Consider the conclusion of your own research. Conclusions must be clear.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The work is written good. The introduction and discussion is good. What is worrying is that these are calculated values for gases. Analytical techniques were not used in in vitro fermentation.
However, the work has extensive statistics, well-described discussions, which speaks to its advantage.
The work is suitable for publication
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Review comments on “In vitro rumen fermentation kinetics, determination, and nutritional evaluation of several non-conventional plants, with potential for ruminant feeding” by Cristiana S.A.M. Maduro Dias etl.
This work presents the study to evaluate the nutritional potential of several non-conventional plants: Pennisetum setaceum, Ricinus communis, Arundo donax, Acacia melanoxylon, Opuntia ficus-indica, Agave americana., Pittosporum undulatum, and Hedychium gardnerianum.
My main general comments are as below:
- The relevance of this study undoubtedly takes place in a changing climate and an increasing population. The authors correctly selected the research methodology, as well as analyzed the data obtained. Meanwhile, there are more modern methods than the ones used by the authors of the article. I just want to draw the attention of the authors to the need to indicate the age, live weight, and breed of animals from which the scar fluid was taken at the slaughterhouse. Since these characteristics indirectly, but affect the composition of the rumen microbiome and, accordingly, the enzymatic characteristics.
- Additionally, it was possible to conduct chemical analysis of plants for the content of tannins, flavonoids, essential oils ... etc., these substances are also of scientific interest, as they affect the methane formation and enzymatic activity of the scar. We recommend that the authors conduct animal studies in vivo to evaluate the use of these plants with the establishment of scar metabolites and conduct metagenomic sequencing (NGS) to establish the microbiome of the scar.
- An important shortcoming is that the author does not highlight the contribution of their manuscript in comparison to the work that has been performed by previous researchers. This can be added in the introduction and/or conclusion section.
- Conclusions need more elaboration about: outcomes, limitations, and possible/future scenarios.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
The results might have practical application especially in the area of forage shortage over the year. The manuscript should be technically improved according to instruction to authors (page numbers etc.)
The main lack of the work is in the material and methods section.
Line 76-79 - it is not clear what was the phenological stage of plant development (how old the plants were in general), what time of the year the samples were collected? It seems only eight plants and three samples per plant were taken for analysis at the same location. Therefore, it can be concluded that the samples were not representative. Besides, the authors should refer to some previous results showing which plant parts, of these plants being investigated, the animals prefer over others (line 77 “consisting of the parts of the plant animals normally eat”).
What was the size of each sample? Whether certain subsamples were taken out and how? How the samples were collected (with scissors)? How the samples were taken, from which part of the plant?
Line 107-108- Ration chemical composition should be presented and also the share of different ration constituents fed to animals. The authors should state how long the animals were fed controlled rations before being slaughtering and rumen fluid taken for in vitro incubation. What was the level of feeding the animals and how was it determined?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
