Supplementation of 5,6-Dimethylbenzimidazole and Cobalt in High-Concentrate Diet Improves the Ruminal Vitamin B₁₂ Synthesis and Fermentation of Sheep

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study examined the dose-response effects of supplementing 5,6-dimethylbenzimidazole and cobalt in the rumen of rams by measuring VB12, pH, ammonia-N, microbial protein, and SCFA concentrations. The results could have used to guide the practice of supplementation. However, the issues in writing and data interpretation compromised the quality of this manuscript.

 

1. "High concentration" was repeatedly mentioned in the title and across the paragraphs, but the definition of "high concentration" has not been well defined, such as what are the recommended concentrations or the concentrations in practice, as well as what are the needs for higher concentrations, in both Introduction and Discussion.

 

2. Inaccurate descriptions in Materials and Methods:

---Line 85: "80 mg/d 5,6-DMB+0.25 mg/kg Co" why in different units? and kg of what (body weight or feed mass)?

---Line 87: what is the adaptation period? what is the sample period?

---Line 103, what is "25 g of concentrate"?

---Line 113, "Ruminal fluid was collected at 0 h before feeding, and 1, 3, 5 and 7 h after feeding during the trial period". Which day in the total 12 days of feeding was the ruminal fluid sample collected?

 

3. Unclear descriptions in Results:

---The statistical differences in multiple comparisons are labeled by * in Figure 1, and then by letters in Tables. Please be consistent.

---The description "Different capital letters on the shoulders of the peer data indicate significant differences (p<0.01), different lowercase letters on the shoulders indicate significant differences (p<0.05), and the same letters or no letters on the shoulders indicate insignificant differences (p>0.05)" is confusing. What means "peer data"? "shoulder"?

---All these tables could be converted to figures for better presentation.

 

3. I consider the lack of data on lactic acid in rumen fluid is a clear defect in this study as the observed the positive correlation between SCFA and pH in Figure 2 can't explain why the B12 treatments had more SCFA than the control (Table 5), but higher pH and less acidic (Table 3). Lactic acid is defined as another important contributor to pH, but its data is lacking. Therefore, the explanation on observed change in pH is incomplete.

Comments on the Quality of English Language

The writing is smooth, but wording could be improved for better accuracy in expression.

Author Response

Dear Editor.
Thank you and the reviewers for your professional review. I am the author of manuscript number: fermentation-2646675. We have carefully revised the paper with reference to the experts' comments and have added and explained the contents added to the paper. The revisions are marked in red in the article. Once again, we thank you and the experts for the expert review.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

It is a well-done research, although there are many previous works on this topic, mainly with dairy cattle. It emphasizes the use of 5,6-dimethylbenzimidazole and cobalt in concentrate diets for sheep. However, a diet with 70 roughage: 30 concentrate is not a high-concentrate diet (Stanton, T.L. & Levalley, S,B. Lamb feedlot nutrition. Fact sheet No. 1613. Colorado State University. Retrieved 12/10/2023. https://extension.colostate.edu/topic-areas/agriculture/lamb-feedlot-nutrition-1-613/). Research has shown that diets higher in forage lead to a higher synthesis of vitamin B12, as reported by Santschi et al. in their study on dairy cows (J. Dairy Sci 2005. 88:2043-2054). In their research, a diet with a 60:40 forage-to-concentrate ratio resulted in more synthesis of vitamin B12 compared to a diet with a 40:60 forage-to-concentrate ratio. Therefore, the forage-to-concentrate ratio in the present study may explain the results obtained.

Comments for author File: Comments.pdf

Author Response

Dear editor.
Thank you and the reviewers for your professional review. I am the author of manuscript number: Fermentation-2646675. We carefully revised the document with reference to expert opinions, and supplemented and explained the content of the document. Revisions are marked in red in the article. We thank you again and the experts for your expert review.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors Comments: Careful proofreading on grammar and wordings is needed. ---Please use the same unit for L-Lactate (mmol/L) and D-Lactate (μg/mL) in Table 6 ---No need to use uppercase for the first letter in a compound name ---"Propionic" alone is not a correct expression. Please use "propionic acid" or "propionate". This also applies to "butyric".   ---Please use "respectively" if enlisting multiple values within the same sentence, such as the last sentence in Abstract and Conclusion.

 

Comments on the Quality of English Language

Careful proofreading on grammar and wordings is needed.

Author Response

Dear Editors,

First of all, we are very sorry for the trouble caused by the mistake of our work. We are very grateful to you and the experts for their professional advice on this manuscript. Based on the comments offered, we have made changes on a case-by-case basis and added more relevant content. Language and phrasing have been carefully revised. We thank you and the experts for your attention to the manuscript.

Sincerely,

Zhiqiang Cheng

 

Author Response File: Author Response.pdf