Effects of Barley- and Oat-Based Diets on Some Gut Parameters and Microbiota Composition of the Small Intestine and Ceca of Broiler Chicken

Round 1

Reviewer 1 Report

This article is generally interesting and well written. My comments aim to increase the scientific soundness and clarity of it. Some minor language ambiguities must be also corrected.

Line 3 – In title only jejunum as a part of the small intestine was mentioned. But the authors also studied the ileum which is another part of the small intestine (line 80, 127, 134). Thus, the title does not reflect fully the content of the research.

Line 28 – please explain what SCFA stands for.

Line 40 – The authors did not mention the role of rye in the nutrition of broiler chickens. It is well known that rye is more resistant to fungal diseases. But unfortunately, it is also rich in NSP, which is why its supplementation with xylanase is necessary. However, it has been recently shown that inclusion of modern varieties of hybrid rye to chickens’ diet substantially improves absorptive surface of the small intestine and may be used as an alternative source of energy (see. Donaldson et al. Modern Hybrid Rye, as an Alternative Energy Source for Broiler Chickens, Improves the Absorption Surface of the Small Intestine Depending on the Intestinal Part and Xylanase Supplementation. Animals 2021, 11, 1349. https://doi.org/10.3390/ani11051349). This issue is definitely in line with the topic of the current article and in Reviewer's opinion the authors should briefly address this issue in the Introduction as well as acknowledge this work.

Line 129 – JC is used as abbreviation of “jejunum content” (line 24) or “jejunal chyme” (line 129). Please unify. As once introduced these abbreviations should be consequently used (lines 131-132, line 223, 249, 254, 282, 301, 307, 379, 394, 440, 456).

Line 130 – The correct anatomical name for is Meckel’s diverticulum is vitelline diverticulum. Please replace it.

Line 130 – was CC collected unilaterally or bilaterally?

Line 144 – please provide country of origin for some hardware (Brookfield DV II – line 143; fused silica column- line 153).

Table 4 – “(mPa.s)” should be moved to column 2 (“viscosity”).

Table 6, 7 and Figure 2, 3 – names of phyla should be written in italics.

Line 340 - In discussion the authors should mention that increased digesta viscosity is not the only one factor influencing the gut permeability. The gut permeability may be also affected by many other non-dietary factors, including hormones, stress or just diseases.

Line 411, 422, 469  – JC, JM and CC were already abbreviated.

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Dear Authors,

The article is very current and is processed at a high scientific level. All chapters are carefully described, and the results with discussion are correctly presented. In further research, I recommend focusing on the content of β-glucans in various wheat hybrids. I have only one question: Why wasn't the granulated form used for the starter mixture but mash?

Best regards,

Reviewer. 

Author Response

Please see the attachment.

Author Response File: Author Response.docx