Effects of Dietary Sweet Potato Tuber Meal on Production Performance, Meat Quality and Intestine of Wenchang Chickens

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript provides potentially useful data on the use of sweet potato tuber meal as a partial energy ingredient in diets for finishing Wenchang chickens. The experimental scale is adequate at the pen level, and the topic is relevant for local poultry production and alternative feed utilization.

However, the manuscript currently suffers from overinterpretation, serious inconsistencies between the fatty acid tables and the text, insufficient statistical rigor, incomplete methodological detail for meat quality and histology measurements, and a conclusion that is not fully aligned with the actual results. Therefore, this manuscript requires several improvements before it can be considered for publication. Below are detailed comments and suggestions for improvement.

Simple Summary
The Simple Summary is clear, but it overstates the findings by saying that 9–12% SPTM improved meat quality and nutrient composition. The 12% group showed lower breast muscle total amino acids, essential amino acids, umami amino acids, Asp, Glu, Thr, and Ser. Please revise the summary to distinguish the apparent benefit of 9% SPTM from the less consistent response at 12%.

Lines 25–28: The phrase “enhanced flavor-related compounds” is too broad. IMP increased at 9%, but several umami amino acids decreased at 12%. Please specify which compounds improved and at which inclusion level.

Abstract
Lines 43–55: The Abstract lists several significant results but does not adequately separate beneficial from potentially unfavorable outcomes. For example, jejunal villus height was lower in the 9% group, and breast muscle total amino acids and umami amino acids were lower in the 12% group. These findings should not be presented as uniformly positive.

Lines 48–49: The reduction in jejunal villus height in the 9% group should not be framed neutrally without interpretation. Lower villus height may indicate reduced absorptive surface area unless supported by additional functional data. Please discuss this carefully.

Lines 54–58: “Improved meat quality and nutrient composition” is too strong. The data suggest selective effects on IMP, IMF, some fatty acids, and muscle fiber traits, but not broad improvement in nutrient composition. Please revise to “altered selected meat quality and nutrient composition indicators.”

Introduction
Lines 64–70: The background on alternative feed resources is appropriate. However, the Introduction should more clearly state whether SPTM replaces corn, starch source, or energy source. This matters because soybean oil was also increased across SPTM diets to maintain metabolizable energy.

Lines 75–79: The nutritional limitations of sweet potato are briefly noted, including low protein, amino acid imbalance, and anti-nutritional factors. Please add more details on how the processing of SPTM was performed, because trypsin inhibitors and starch gelatinization/digestibility can depend strongly on processing.

Lines 92–99: The discussion of IMF and flavor precursor deposition in Wenchang chickens is relevant. However, the claim that lauric acid and myristic acid are key accumulated fatty acids in this breed needs stronger support or clarification.

Lines 104–109: The objective is clear. However, the manuscript later concludes “intestinal health” despite measuring only jejunal morphology and not gut barrier genes, digestive enzymes, mucosal immunity, short-chain fatty acids, or microbiota. Please moderate the wording to “jejunal morphology” unless additional intestinal health data are included.

Materials and Methods
Lines 112–116: The nutrient composition of SPTM is provided, but important information is missing: processing method, drying temperature, particle size, starch content, amylose/amylopectin ratio, anti-nutritional factors, and mycotoxin status. These are important for interpreting SPTM as a feed ingredient.

Lines 118–132: The design is acceptable, with 400 birds, four treatments, five replicates, and 20 birds per replicate. However, the experimental unit should be explicitly stated. For growth performance, the pen/replicate - not the individual bird - is the experimental unit. For slaughter, serum, histology, and meat data, the selected birds are subsamples nested within replicates.

Lines 122–124: The diets were formulated according to Chinese requirements, but Table 1 shows soybean oil increasing from 3.00% to 4.60% as SPTM inclusion increases. This may confound interpretation because observed changes could be related to soybean oil adjustment, not only SPTM. Please discuss this limitation and consider analyzing whether dietary lipid changes explain the meat fatty acid results.

Lines 133–139: Table 1 contains formatting and wording issues. “nutritent levels” should be “nutrient levels.” “Dried sweet potato powder (%)” should be standardized with the term SPTM. The premix description begins with “Table 10. IU,” which appears to be a formatting error and probably should refer to vitamin A.

Lines 146–154: The slaughter sampling method selects two chickens per replicate with body weights close to the replicate average. This is reasonable, but please state the total sample size used for slaughter traits (n=10 per treatment) and clarify whether replication was accounted for statistically.

Lines 161–170: Serum assays are underdescribed. Please provide kit catalog numbers, detection ranges, intra- and inter-assay CVs, and whether samples were assayed in duplicate.

Lines 172–180: Intestinal morphology methods need more detail. Please specify the number of villi and crypts measured per bird, whether measurements were blinded, and the image analysis software used. The method currently mentions a fluorescence microscope, but H&E sections are usually assessed by light microscopy; please clarify.

Lines 181–185: Meat quality methodology is insufficient. The manuscript does not describe the instruments, timing, calibration, temperature, measurement sites, or protocols for pH, color, drip loss, cooking loss, shear force, IMF, IMP, amino acids, or fatty acids. These details are essential for reproducibility.

Lines 186–191: Muscle fiber morphology methods are too brief. Please specify how many fields/images were analyzed per sample, magnification, software, thresholding method, and whether the analyst was blinded to treatment.

Lines 192–197: The statistical analysis should be improved. One-way ANOVA with Duncan’s multiple range test is minimal and does not address dose-response. Please add orthogonal polynomial contrasts for linear and quadratic effects of SPTM inclusion. Also consider false discovery rate control due to the large number of endpoints.

Results
Lines 199–205: Growth performance results are clearly stated. However, Table 2 should indicate the experimental unit and n. Mortality is shown, but the statistical analysis for mortality is not described. Mortality is a proportion and should not be analyzed in the same way as continuous variables unless transformed or modeled appropriately.

Lines 207–213: Slaughter traits were not significantly affected. This is important because later conclusions about improved meat quality should not imply improved production yield.

Lines 220–227: Serum biochemical parameters showed no significant differences. The manuscript should avoid claiming broad physiological improvement.

Lines 228–240: ALT and AST results are statistically significant in selected comparisons, but their biological meaning is not discussed carefully. Since all values may still be within physiological range, please avoid implying improved hepatic function unless reference ranges or clinical interpretation are provided.

Lines 241–253: The Results section contains a contradiction. It states that jejunal villus height in the 9% group was significantly lower than the control and 12% groups, but then says “No significant differences were observed among groups in villus height.” Please correct this inconsistency.

Lines 255–263: Breast muscle physicochemical properties did not differ among groups. This directly weakens the conclusion that SPTM improved tenderness or broad meat quality. Please ensure the Discussion reflects this negative result.

Lines 273–285: Breast muscle moisture was lower and IMF higher in the 12% group; IMP was higher in the 9% group. These are important findings. However, it is inaccurate to state that 9–12% uniformly improved meat quality; the response appears trait-specific.

Lines 296–312: The amino acid data in breast muscle show that the 12% group had lower TAA, EAA, UAA, Asp, Glu, Thr, and Ser. This conflicts with the Abstract and Conclusion claiming improved nutrient composition. Please revise the interpretation substantially.

Lines 313–329: The leg muscle amino acid table appears suspiciously similar to the breast muscle amino acid table for many individual amino acids. Please verify whether Table 13 is correctly presented and not accidentally duplicated or partially copied from Table 12.

Lines 333–347: There is a serious discrepancy between the Results text and Table 14. The text states that the 12% group had higher TFA, SFA, MUFA, PUFA and multiple individual fatty acids, but Table 14 shows the 9% group has the highest values for many of these traits and the 12% group appears identical to the 0% group for several rows. Please recheck the raw data, table values, statistical superscripts, and written interpretation. This must be corrected before review can proceed reliably.

Lines 350–357: A similar issue appears in Table 15. The text says lauric acid and myristic acid contents in the 9% and 12% groups were higher than the 0% and 3% groups, but Table 15 shows the 12% group appears identical to the 0% group for lauric and myristic acid. Please verify and correct.

Lines 359–369: In Table 16, average fiber area is reported as 0.00 ± 0.00, which is not meaningful. Please report values with appropriate decimal precision or use µm² instead of mm². The current units and rounding obscure the data.

Lines 371–384: The same issue occurs in Table 17: average fiber area is reported as 0.00 ± 0.00. Please revise units and decimal precision.

Figure 1, Page 13: The histological images are useful but need improvement. The images should include clearer labels, higher resolution, consistent magnification, and quantified measurement regions. The scale bar is stated as 20 µm, but the figure legend does not specify staining method or magnification.

Discussion
Lines 385–408: The Discussion begins with a general meat quality rationale, but the interpretation is too strong. The statement that ~9% SPTM “maintains water-holding capacity and promotes lipid deposition” is not fully supported because pH, drip loss, color, and other physicochemical traits were not significantly affected, and IMF increase was strongest at 12%, not clearly at 9%.

Lines 412–420: The IMP interpretation is plausible, but the proposed mechanism involving carbohydrate-driven ATP degradation is speculative. No muscle energy metabolism markers were measured. Please rephrase as a hypothesis.

Lines 421–434: The Discussion claims that 12% supplementation increased amino acid content in leg muscle, but breast muscle amino acid composition was negatively affected at 12%. This contrast should be discussed explicitly rather than presenting 12% SPTM as generally beneficial.

Lines 435–446: The fatty acid interpretation cannot be accepted until the inconsistency between Tables 14–15 and the text is resolved. Also, the claim that higher SPTM modifies lipid deposition by regulating lipid-metabolism enzymes is unsupported because no enzyme activity, gene expression, or metabolomic data were collected.

Lines 447–455: The muscle fiber interpretation needs correction. The text states that 12% SPTM reduced breast muscle fiber diameter, but Table 16 shows the 12% group has the lowest value with a different superscript. However, the biological interpretation should be approached with caution because no shear force or sensory data support improved tenderness.

Lines 385–455: The discussion lacks a limitations paragraph. The authors should add limitations including absence of digestibility measurements, no gut microbiota data, no intestinal barrier or inflammatory gene expression, no sensory analysis, no metabolomics, possible confounding by soybean oil adjustment, and a large number of endpoints without multiple testing correction.

Conclusion
The conclusion is overstated. “Significantly optimized the fatty acid composition and muscle fiber structure” is not appropriate, given the data inconsistencies and the absence of sensory, shear force, or molecular validation. The statement that SPTM enhances tenderness is not supported, as no shear-force data are presented. Please revise to a narrower conclusion: SPTM up to 12% did not impair growth or slaughter traits, 9% increased breast IMP, 12% increased breast IMF but reduced several breast amino acid indices, and further validation is needed.

Ethics, conflicts, and references

Lines 477–478: Institutional Review Board Statement says “Not applicable,” but Methods provide IACUC approval number HNSYY20230721. This is inconsistent. Please correct to match the Methods.

Lines 479–484: Conflict of interest statement identifies one author affiliated with a company/key laboratory. This is acceptable, but the manuscript should clarify whether the company supplied animals, feed, facilities, or had any role in study design or data interpretation.

Lines 485–600: Several references appear weakly matched to the claims. For example, references on sepsis, gestational diabetes, cheese bacteria, shrimp thawing, and beef processing appear unrelated or only loosely related to chicken meat quality and SPTM nutrition. Please replace weakly relevant references with more directly relevant poultry nutrition and meat quality studies.

Author Response

Response to reviewer

Summary

Thank you for your comments concerning our manuscript. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:

 

Reviewer:

Questions for General Evaluation	Reviewer's Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Can be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Is the research design appropriate?	Can be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Are the methods adequately described?	Must be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Are the results clearly presented?	Must be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Are the conclusions supported by the results?	Must be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Are all figures and tables clear and well-presented?	Must be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.

 

Comments and Suggestions for Authors

This manuscript provides potentially useful data on the use of sweet potato tuber meal as a partial energy ingredient in diets for finishing Wenchang chickens. The experimental scale is adequate at the pen level, and the topic is relevant for local poultry production and alternative feed utilization.

However, the manuscript currently suffers from overinterpretation, serious inconsistencies between the fatty acid tables and the text, insufficient statistical rigor, incomplete methodological detail for meat quality and histology measurements, and a conclusion that is not fully aligned with the actual results. Therefore, this manuscript requires several improvements before it can be considered for publication. Below are detailed comments and suggestions for improvement.

 

Simple Summary
(1) Comment1
The Simple Summary is clear, but it overstates the findings by saying that 9–12% SPTM improved meat quality and nutrient composition. The 12% group showed lower breast muscle total amino acids, essential amino acids, umami amino acids, Asp, Glu, Thr, and Ser. Please revise the summary to distinguish the apparent benefit of 9% SPTM from the less consistent response at 12%.
Response: We thank the reviewer for this careful observation. We agree that the original wording overgeneralized the effects of SPTM. In the revised manuscript, we will modify the Simple Summary to clearly distinguish the effects at 9% versus 12% inclusion, with all modifications highlighted in yellow for your convenience, please see line 26-28 of revised manuscript.

 

• Comment2
  Lines 25–28: The phrase “enhanced flavor-related compounds” is too broad. IMP increased at 9%, but several umami amino acids decreased at 12%. Please specify which compounds improved and at which inclusion level.
  Response:We agree and will specify in the Simple Summary that at 9% SPTM, IMP was significantly increased, while at 12% SPTM, several umami amino acids (e.g., glutamic acid, aspartic acid) and essential amino acids decreased. We will remove the vague phrase “flavor-related compounds”, with all modifications highlighted in yellow for your convenience, please see line 26-28 of revised manuscript.

Abstract

• Comment3
  Lines 43–55: The Abstract lists several significant results but does not adequately separate beneficial from potentially unfavorable outcomes. For example, jejunal villus height was lower in the 9% group, and breast muscle total amino acids and umami amino acids were lower in the 12% group. These findings should not be presented as uniformly positive.
  Response:Thank you for your comment. We will revise the Abstract to present both positive and negative findings in a balanced manner. We have revised the Abstract by removing several statements based on results that were not statistically significant, thereby avoiding overinterpretation of the findings.
• Comment4
  Lines 48–49: The reduction in jejunal villus height in the 9% group should not be framed neutrally without interpretation. Lower villus height may indicate reduced absorptive surface area unless supported by additional functional data. Please discuss this carefully.
  Response:We agree. In the revised Results section, we will not interpret the reduced villus height as a positive or neutral outcome. Instead, we will state the observation descriptively and, in the Discussion, acknowledge that lower villus height may suggest reduced absorptive capacity, although no negative effects on growth performance were observed.
• Comment5
  Lines 54–58: “Improved meat quality and nutrient composition” is too strong. The data suggest selective effects on IMP, IMF, some fatty acids, and muscle fiber traits, but not broad improvement in nutrient composition. Please revise to “altered selected meat quality and nutrient composition indicators.”
  Response:Thank you for your comment. We fully agree and will revise the Abstract conclusion accordingly. with all modifications highlighted in yellow for your convenience, please see line 54-55 of revised manuscript.
• Comment6
  Introduction
  Lines 64–70: The background on alternative feed resources is appropriate. However, the Introduction should more clearly state whether SPTM replaces corn, starch source, or energy source. This matters because soybean oil was also increased across SPTM diets to maintain metabolizable energy.
  Response:As elucidated in the introduction section, SPTM serves as an alternative to corn, please see line 79-81 of revised manuscript.
• Comment7
  Lines 75–79: The nutritional limitations of sweet potato are briefly noted, including low protein, amino acid imbalance, and anti-nutritional factors. Please add more details on how the processing of SPTM was performed, because trypsin inhibitors and starch gelatinization/digestibility can depend strongly on processing.
  Response:We will add a description of SPTM processing in the Materials and Methods section (2.1). The sweet potato tubers were washed, sliced, sun-dried for 48 hours, and then ground to pass through a 0.5-mm sieve. No heat treatment was applied, which may preserve some trypsin inhibitor activity. This information will help interpret the results.
• Comment8
  Lines 92–99: The discussion of IMF and flavor precursor deposition in Wenchang chickens is relevant. However, the claim that lauric acid and myristic acid are key accumulated fatty acids in this breed needs stronger support or clarification.
  Response:We will revise this sentence to indicate that lauric and myristic acids are examples of fatty acids that may be influenced by diet in this breed, rather than claiming they are inherently key accumulated fatty acids. We will cite relevant references [13-15] on indigenous chicken fatty acid profiles.
• Comment9
  Lines 104–109: The objective is clear. However, the manuscript later concludes “intestinal health” despite measuring only jejunal morphology and not gut barrier genes, digestive enzymes, mucosal immunity, short-chain fatty acids, or microbiota. Please moderate the wording to “jejunal morphology” unless additional intestinal health data are included.
  Response:We agree and will change all instances of “intestinal health” to “jejunal morphology” throughout the manuscript. We will not overclaim intestinal health effects based solely on morphology.

Materials and Methods

• Comment10
  Lines 112–116: The nutrient composition of SPTM is provided, but important information is missing: processing method, drying temperature, particle size, starch content, amylose/amylopectin ratio, anti-nutritional factors, and mycotoxin status. These are important for interpreting SPTM as a feed ingredient.
  Response:We will add a description of SPTM processing in the Materials and Methods section (2.1).
• Comment11
  Lines 118–132: The design is acceptable, with 400 birds, four treatments, five replicates, and 20 birds per replicate. However, the experimental unit should be explicitly stated. For growth performance, the pen/replicate - not the individual bird - is the experimental unit. For slaughter, serum, histology, and meat data, the selected birds are subsamples nested within replicates.
  Response:We will explicitly state the experimental unit in the statistical analysis section. Pen (n=5 per treatment) will be the unit for growth performance, and individual bird (n=10 per treatment, 2 per pen) will be the unit for other measurements, with pen included as a random effect in the ANOVA model where appropriate.
• Comment12
  Lines 122–124: The diets were formulated according to Chinese requirements, but Table 1 shows soybean oil increasing from 3.00% to 4.60% as SPTM inclusion increases. This may confound interpretation because observed changes could be related to soybean oil adjustment, not only SPTM. Please discuss this limitation and consider analyzing whether dietary lipid changes explain the meat fatty acid results.
  Response:Thank you for this insightful comment. We agree that the gradual increase in soybean oil inclusion (from 3.00% to 4.60%) across the dietary treatments represents a potential confounding factor that should be acknowledged. In the present study, SPTM was used primarily as a partial substitute for corn. Because SPTM contains lower metabolizable energy than corn, soybean oil was increased to maintain isoenergetic diets according to the nutrient requirements of Chinese indigenous yellow-feathered chickens.
• Comment13
  Lines 133–139: Table 1 contains formatting and wording issues. “nutritent levels” should be “nutrient levels.” “Dried sweet potato powder (%)” should be standardized with the term SPTM. The premix description begins with “Table 10. IU,” which appears to be a formatting error and probably should refer to vitamin A.
  Response:Thank you for your comment. We will correct all formatting and wording issues in Table 1.
• Comment14
  Lines 146–154: The slaughter sampling method selects two chickens per replicate with body weights close to the replicate average. This is reasonable, but please state the total sample size used for slaughter traits (n=10 per treatment) and clarify whether replication was accounted for statistically.
  Response:We will clearly state: “For slaughter performance, two chickens per replicate (n=10 per treatment) were selected, a total of 40 chickens were slaughtered across the four groups.” In the statistical model, we will include pen as a random effect nested within treatment.
• Comment15
  Lines 161–170: Serum assays are underdescribed. Please provide kit catalog numbers, detection ranges, intra- and inter-assay CVs, and whether samples were assayed in duplicate.
  Response:Thank you for your comment. The relevant testing methods have been fully supplemented. Intra-assay CV < 5%, inter-assay CV < 8%. Samples were assayed in duplicate.
• Comment16
  Lines 172–180: Intestinal morphology methods need more detail. Please specify the number of villi and crypts measured per bird, whether measurements were blinded, and the image analysis software used. The method currently mentions a fluorescence microscope, but H&E sections are usually assessed by light microscopy; please clarify.
  Response:We will specify: 10 well-oriented villi and crypts per bird were measured. The analyst was blinded to treatment. ImageJ software (NIH) was used for measurements. Light microscopy (not fluorescence) was used for H&E-stained sections.
• Comment17
  Lines 181–185: Meat quality methodology is insufficient. The manuscript does not describe the instruments, timing, calibration, temperature, measurement sites, or protocols for pH, color, drip loss, cooking loss, shear force, IMF, IMP, amino acids, or fatty acids. These details are essential for reproducibility.
  Response:We will provide a detailed subsection (2.3.6) with all requested information.
• Comment18
  Lines 186–191: Muscle fiber morphology methods are too brief. Please specify how many fields/images were analyzed per sample, magnification, software, thresholding method, and whether the analyst was blinded to treatment.
  Response:We will specify: Five random fields per section at 200× magnification (Olympus BX53). ImageJ software with manual thresholding. Fiber number, area, and diameter were measured. Analyst was blinded to treatment. Units will be changed from mm² to µm².
• Comment19
  Lines 192–197: The statistical analysis should be improved. One-way ANOVA with Duncan’s multiple range test is minimal and does not address dose-response. Please add orthogonal polynomial contrasts for linear and quadratic effects of SPTM inclusion. Also consider false discovery rate control due to the large number of endpoints.

Response: Thank you for this constructive suggestion, with all modifications highlighted in yellow for your convenience, please see line 227-237 of revised manuscript.
Results

• Comment20
  Lines 199–205: Growth performance results are clearly stated. However, Table 2 should indicate the experimental unit and n. Mortality is shown, but the statistical analysis for mortality is not described. Mortality is a proportion and should not be analyzed in the same way as continuous variables unless transformed or modeled appropriately.
  Response:Thank you for your comment. The experimental unit has been indicated in the header of Table 2. The sample size (n) was already specified in the Materials and Methods section. In addition, the mortality data have been removed from Table 2 to avoid potential ambiguity and misinterpretation.
• Comment21
  Lines 207–213: Slaughter traits were not significantly affected. This is important because later conclusions about improved meat quality should not imply improved production yield.
  Response:We agree. In the revised conclusion and discussion, we will explicitly state that SPTM did not affect slaughter yield, and that the observed meat quality changes occurred without compromising production performance.
• Comment22
  Lines 220–227: Serum biochemical parameters showed no significant differences. The manuscript should avoid claiming broad physiological improvement.
  Response:We agree. In the revised conclusion and discussion, we will explicitly state that SPTM did not affect slaughter yield, and that the observed meat quality changes occurred without compromising production performance.
• Comment23
  Lines 228–240: ALT and AST results are statistically significant in selected comparisons, but their biological meaning is not discussed carefully. Since all values may still be within physiological range, please avoid implying improved hepatic function unless reference ranges or clinical interpretation are provided.
  Response:Thank you for your comment. The statistical differences are not indicative of clinically meaningful hepatic changes.
• Comment24
  Lines 241–253: The Results section contains a contradiction. It states that jejunal villus height in the 9% group was significantly lower than the control and 12% groups, but then says “No significant differences were observed among groups in villus height.” Please correct this inconsistency.
  Response:Thank you for your comment. This is an error in the original manuscript. The contradictory sentence will be removed.
• Comment25
  Lines 255–263: Breast muscle physicochemical properties did not differ among groups. This directly weakens the conclusion that SPTM improved tenderness or broad meat quality. Please ensure the Discussion reflects this negative result.
  Response:Thank you for your comment. We will make the necessary adjustments during the discussion.
• Comment26
  Lines 273–285: Breast muscle moisture was lower and IMF higher in the 12% group; IMP was higher in the 9% group. These are important findings. However, it is inaccurate to state that 9–12% uniformly improved meat quality; the response appears trait-specific.
  Response:Thank you for your comment. We will make the necessary adjustments during the revised manuscript.
• Comment27
  Lines 296–312: The amino acid data in breast muscle show that the 12% group had lower TAA, EAA, UAA, Asp, Glu, Thr, and Ser. This conflicts with the Abstract and Conclusion claiming improved nutrient composition. Please revise the interpretation substantially.
  Response:Thank you for your comment. The relevant statements in the Abstract, Results, Discussion, and Conclusion sections have been revised to more accurately reflect the experimental findings, with all modifications highlighted in yellow for your convenience
• Comment28
  Lines 313–329: The leg muscle amino acid table appears suspiciously similar to the breast muscle amino acid table for many individual amino acids. Please verify whether Table 13 is correctly presented and not accidentally duplicated or partially copied from Table 12.
  Response:Thank you for your comment. We have carefully rechecked our raw data and confirm that Table 13 (leg muscle amino acids) is correct and distinct from Table 12 (breast muscle). However, some values for individual amino acids in the control group were inadvertently copied incorrectly. We will correct Table 13 with the accurate leg muscle data. We apologize for this error.
• Comment29
  Lines 333–347: There is a serious discrepancy between the Results text and Table 14. The text states that the 12% group had higher TFA, SFA, MUFA, PUFA and multiple individual fatty acids, but Table 14 shows the 9% group has the highest values for many of these traits and the 12% group appears identical to the 0% group for several rows. Please recheck the raw data, table values, statistical superscripts, and written interpretation. This must be corrected before review can proceed reliably.
  Response:We thank the reviewer for catching this critical error. We have carefully reviewed the original data and confirmed that Table 14 contained a copy error, which we have now fully corrected. We apologize for this mistake.
• Comment30
  Lines 350–357: A similar issue appears in Table 15. The text says lauric acid and myristic acid contents in the 9% and 12% groups were higher than the 0% and 3% groups, but Table 15 shows the 12% group appears identical to the 0% group for lauric and myristic acid. Please verify and correct.
  Response:We thank the reviewer for catching this critical error. We have carefully reviewed the original data and confirmed that Table 15 contained a copy error, which we have now fully corrected. We apologize for this mistake.
• Comment31
  Lines 359–369: In Table 16, average fiber area is reported as 0.00 ± 0.00, which is not meaningful. Please report values with appropriate decimal precision or use µm² instead of mm². The current units and rounding obscure the data.
  Response:We have carefully reviewed the original data and confirmed that Table 16 contained a copy error, which we have now fully corrected. We will change the unit from mm² to µm² for average fiber area in Table 16. Values will be reported with appropriate significant digits. The same correction will be applied to fiber diameter (µm).
• Comment32
  Lines 371–384: The same issue occurs in Table 17: average fiber area is reported as 0.00 ± 0.00. Please revise units and decimal precision.
  Response:We have carefully reviewed the original data and confirmed that Table 17 contained a copy error, which we have now fully corrected. We will change the unit from mm² to µm² for average fiber area in Table 17. Values will be reported with appropriate significant digits. The same correction will be applied to fiber diameter (µm).
• Comment33
  Figure 1, Page 13: The histological images are useful but need improvement. The images should include clearer labels, higher resolution, consistent magnification, and quantified measurement regions. The scale bar is stated as 20 µm, but the figure legend does not specify staining method or magnification.
  Response:Thank you for this constructive suggestion, with all modifications highlighted in yellow for your convenience, please see line 424 of revised manuscript.

Discussion

• Comment34
  Lines 385–408: The Discussion begins with a general meat quality rationale, but the interpretation is too strong. The statement that ~9% SPTM “maintains water-holding capacity and promotes lipid deposition” is not fully supported because pH, drip loss, color, and other physicochemical traits were not significantly affected, and IMF increase was strongest at 12%, not clearly at 9%.
  Response:We appreciate the reviewer's comment and agree that the available data do not provide sufficient evidence to support this conclusion. Accordingly, the statement has been removed from the revised manuscript to ensure that the interpretation remains fully consistent with the experimental findings.
• Comment35
  Lines 412–420: The IMP interpretation is plausible, but the proposed mechanism involving carbohydrate-driven ATP degradation is speculative. No muscle energy metabolism markers were measured. Please rephrase as a hypothesis.
  Response:Thank you for this insightful comment. We agree that the original statement implied a mechanistic interpretation that was not directly supported by the data. Since ATP degradation products and muscle energy metabolism-related parameters were not measured in the present study, the proposed explanation has been revised and presented as a hypothesis rather than a confirmed mechanism. The revised discussion now states that the increased IMP content may be associated with changes in postmortem energy metabolism, while acknowledging that further studies are required to verify this possibility.
• Comment36
  Lines 421–434: The Discussion claims that 12% supplementation increased amino acid content in leg muscle, but breast muscle amino acid composition was negatively affected at 12%. This contrast should be discussed explicitly rather than presenting 12% SPTM as generally beneficial.
  Response:Thank you for this insightful comment. We agree that the original discussion overemphasized the positive response observed in leg muscle while overlooking the reduction in amino acid concentrations detected in breast muscle. Therefore, the Discussion has been revised to explicitly acknowledge the contrasting responses between breast and leg muscles. The revised text now emphasizes that the effects of 12% SPTM on amino acid deposition appear to be muscle-specific rather than uniformly beneficial and that the underlying mechanisms require further investigation.
• Comment37
  Lines 435–446: The fatty acid interpretation cannot be accepted until the inconsistency between Tables 14–15 and the text is resolved. Also, the claim that higher SPTM modifies lipid deposition by regulating lipid-metabolism enzymes is unsupported because no enzyme activity, gene expression, or metabolomic data were collected.
  Response:We thank the reviewer for catching this critical error. We have carefully reviewed the original data and confirmed that Tables 14 and 15 contained a copy error, which we have now fully corrected. We apologize for this mistake.
• Comment38
  Lines 447–455: The muscle fiber interpretation needs correction. The text states that 12% SPTM reduced breast muscle fiber diameter, but Table 16 shows the 12% group has the lowest value with a different superscript. However, the biological interpretation should be approached with caution because no shear force or sensory data support improved tenderness.
  Response:We have carefully reviewed the original data and confirmed that Table 16 contained a copy error, which we have now fully corrected.
• Comment39
  Lines 385–455: The discussion lacks a limitations paragraph. The authors should add limitations including absence of digestibility measurements, no gut microbiota data, no intestinal barrier or inflammatory gene expression, no sensory analysis, no metabolomics, possible confounding by soybean oil adjustment, and a large number of endpoints without multiple testing correction.
  Response:Thank you for this constructive suggestion, with all modifications highlighted in yellow of revised manuscript.

Conclusion

• Comment40
  The conclusion is overstated. “Significantly optimized the fatty acid composition and muscle fiber structure” is not appropriate, given the data inconsistencies and the absence of sensory, shear force, or molecular validation. The statement that SPTM enhances tenderness is not supported, as no shear-force data are presented. Please revise to a narrower conclusion: SPTM up to 12% did not impair growth or slaughter traits, 9% increased breast IMP, 12% increased breast IMF but reduced several breast amino acid indices, and further validation is needed.
  Response:We fully agree and will rewrite the conclusion as follows: “In conclusion, dietary SPTM up to 12% did not negatively affect growth or slaughter performance of Wenchang chickens. Supplementation with 9% SPTM increased breast IMP content, while 12% SPTM increased breast IMF but reduced several amino acid indices. These selective effects on meat quality traits suggest that SPTM has potential as a partial corn replacer, but further studies are needed to optimize inclusion levels and validate sensory outcomes.”

 

Ethics, conflicts, and references

• Comment42
  Lines 477–478: Institutional Review Board Statement says “Not applicable,” but Methods provide IACUC approval number HNSYY20230721. This is inconsistent. Please correct to match the Methods.
  Response:We will correct the statement to: “The experimental design and procedures were approved by the Institutional Animal Care and Use Committee of the Institute of Animal Science and Veterinary Medicine, Hainan Academy of Agricultural Sciences (Approval No.: HNSYY20230721).”
• Comment43
  Lines 479–484: Conflict of interest statement identifies one author affiliated with a company/key laboratory. This is acceptable, but the manuscript should clarify whether the company supplied animals, feed, facilities, or had any role in study design or data interpretation.
  Response:We will revise the conflict of interest statement to include: “Xiuping Wang is employed by Hainan (Tan Niu) Wenchang Chicken Co., Ltd., which provided the experimental animals but had no role in study design, data collection, analysis, interpretation, or manuscript writing. All other authors declare no competing interests.”
• Comment44
  Lines 485–600: Several references appear weakly matched to the claims. For example, references on sepsis, gestational diabetes, cheese bacteria, shrimp thawing, and beef processing appear unrelated or only loosely related to chicken meat quality and SPTM nutrition. Please replace weakly relevant references with more directly relevant poultry nutrition and meat quality studies.

Response: We will carefully review the reference list and replace weakly relevant references.

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

the present manuscript " Effects of dietary sweet potato tuber meal on production performance, meat quality and intestinal health of Wenchang chickens" (biology-4362872) by Jingli Yuan , Quanwei Liu, Jie Liu , Limin Wei , Qiqi Guo , Yan Zhang , Xiuping Wang , Guiping Zhao (the authors) is important and actual work. It is in a frame of the major scopes of the MDPI-journals, but better "Animals" than " Biology ". The aim of the manuscript is "to investigate the effects of dietary supplementation” with sweet potato tuber meal (SPTM) on growth and slaughter performance, physiological and biochemical parameters “of 81-day-old female Wenchang chickens”.  It is positive that the authors  used for this study a total of 400 Wenchang chickens with the same genetic background and similar body weight.  It is important that these chickens were fed diets supplemented with 0%, 3%, 9%, and 12% SPTM, respectively (during the experimental period of 40 days). The authors have written: “The results showed that dietary SPTM supplementation had no significant effects on growth performance, slaughter performance, organ indices, or serum biochemical parameters …”, that is not completely adequate, in my opinion, and is described in my comments below.  It is difficult to accept the authors conclusions that “dietary supplementation with 9%-12% SPTM improved meat quality and nutrient composition of Wenchang chickens aged 81 to 120 days”.

 In particular,  the authors found only some effects on the limited parameters (some serum enzyme activities, immune parameters, jejunal morphology, nutrient composition).  In my opinion, just one effect on the serum alanine aminotransferase (ALT) activity in the 9% SPTM group (0.4 U/L) can be experimental error, because all other groups have almost the same activity levels (1.1-1.3 U/L) in the table 6, whereas in some published research concerning the ALT values in broiler-chicken blood have been around 5-11 U/L. In the case of aspartate aminotransferase (AST) activity in the 3% SPTM group (249.5 U/L) was significantly lower than that in the 12% SPTM group (408.5 U/L), whereas in some published research concerning the AST values in broiler-chicken blood have been around 60-110 U/L. Thus, the additional systematic investigations of the normal values of the physiological and biochemical parameters chicken blood at various age groups, not only the effects of SPTM addition, must be provided in this manuscript.

In general, I do not doubt the technical quality of the work and feel that there is a sufficient impact on a broader readership to justify publication in the research journal, but better "Animals" than " Biology ". All parts of the manuscript are clearly written, relevant for the field and presented in a well-structured manner. It is important that the subject matter has been treated in depth. All the cited references are relevant. There are 51 references have been cited and discussed in this manuscript in total, but only 13 from all the references have been discussed in the “Introduction”. In general, the part “Introduction” is rather short. This manuscript is scientifically sound and it experimental design is appropriate to test the author’s hypothesis. The majority of the tables and all figures are appropriate and properly show the data. The data is interpreted appropriately and consistently throughout the manuscript. The statistical analysis of the data acquired are correct. The ethics statements and data availability statements are adequate. Thus, the present manuscript is actual and important in the field of the poultry biology and husbandry. Only some conclusions consistent not with all the data presented.  

 There are some essential comments on the scientific part of this manuscript, as well as there are some technical remarks. It will be very useful, if the authors can provide the following corrections in the text: 

1. Materials and methods. “2.2. Experimental Design” (page 3, lines 121-122). The authors wrote: “The chickens were fed a basal diet supplemented with 0%, 3%, 9%, and 12% SPTM, respectively”. The question is the following:  why birds were not fed diets supplemented with 6% SPTM ? 
2. There is no explanation: a) why is ADG decreasing at 2.86% (Table 2. from 14.32 g in the control group till 13.91 g in the group fed with 12% SPTM addition) , b) why, at the same time ADFI is increasing from 86.56 g till 87.54 g.( see Table 2). It looks like chicken are eating more, but have less relative growth dynamics, that is negative result.
3. It is also strange that the difference between final and initial body weight (divided by 40 days) is giving another ADG value in my calculation as compared to the Table 2 (presented in the appropriate column in the table 2, page 6).
4. There is no explanation, why is “leg or breast muscle weight” decreasing by addition of 3% and 6% SPTM at about 7.66% or 11.16%, as well as becoming almost the same as for control group by 12% SPTM addition. see Table 3 .
5. There is no explanation, why heart , spleen, by 33.04%, gizzard and liver, 9.03%, indexes are little bit increasing, whereas stomach and proventriculus are slightly decreasing. see Table 4.
6. There is no explanation, why are the key biochemical parameters of chicken blood serum (see Tables 5 and 6) different from those, published by many other researchers, as well as  the nutrient composition of breast and leg muscle. see Tables 10 and 11.
7. There is no explanation why total amount of amino acids is decreasing by increasing SPTM addition, from 3% to 12%, in the breast and leg muscle at 12.31% and 10.43%, respectively. It looks like by adding of the SPTM, the quality of chicken meat is getting worse and worse. see Table 12 and 13.
8. It's important to withdraw the column average fiber area from the table 17, because there are only zero values.
9. There almost no discussion about all these points (in the row from 1 to 7) in the part 3. “Discussion”.
10. The part “Conclusions” is too short. The particular application of 9% or 12% SPTM addition (mentioned by the authors as one data interval : “9% -12% SPTM” at line 457) must be proved and mentioned separately , not as the one data interval.

All the points mentioned above (in the row from 1 to 10) must be clarified before the further procedure of this manuscript. 

Author Response

Response to reviewer

Summary

Thank you for your comments concerning our manuscript. Those comments are all valuable and very helpful for revising and improving our paper, as well as the important guiding significance to our researches. We have studied comments carefully and have made correction which we hope meet with approval. Revised portions are marked in red in the paper. The main corrections in the paper and the responds to the reviewer’s comments are as flowing:

 

Reviewer:

Questions for General Evaluation	Reviewer's Evaluation	Response and Revisions
Does the introduction provide sufficient background and include all relevant references?	Can be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Is the research design appropriate?	Can be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Are the methods adequately described?	Can be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Are the results clearly presented?	Can be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Are the conclusions supported by the results?	Can be improved	We have incorporated in the manuscript, with all modifications highlighted in yellow.
Are all figures and tables clear and well-presented?	Yes

 

The present manuscript " Effects of dietary sweet potato tuber meal on production performance, meat quality and intestinal health of Wenchang chickens" (biology-4362872) by Jingli Yuan , Quanwei Liu, Jie Liu , Limin Wei , Qiqi Guo , Yan Zhang , Xiuping Wang , Guiping Zhao (the authors) is important and actual work. It is in a frame of the major scopes of the MDPI-journals, but better "Animals" than " Biology ".

Response: Thank you very much for your thorough and constructive review of our manuscript. We greatly appreciate your recognition of the importance and relevance of our work. Regarding your suggestion about the journal fit, we acknowledge that "Animals" may be a good fit for this study. However, we believe our manuscript also aligns well with the scope of "Biology", particularly in the areas of poultry physiology, nutritional biochemistry, and intestinal health. Nevertheless, we will consider your suggestion for future submissions. We have carefully addressed all your comments and provided point-by-point responses below.

 

There are some essential comments on the scientific part of this manuscript, as well as there are some technical remarks. It will be very useful, if the authors can provide the following corrections in the text: 

• Comment 1

Materials and methods. “2.2. Experimental Design” (page 3, lines 121-122). The authors wrote: “The chickens were fed a basal diet supplemented with 0%, 3%, 9%, and 12% SPTM, respectively”. The question is the following:  why birds were not fed diets supplemented with 6% SPTM ?

Response: We confirm that the 6% SPTM treatment group was indeed included in the original experimental design. A total of five treatment groups (0%, 3%, 6%, 9%, and 12% SPTM) were initially planned and implemented. However, after a thorough review of the data, we observed that the 6% SPTM group consistently showed intermediate values between the 3% and 9% groups for nearly all measured parameters, including growth performance, serum biochemistry, meat quality, and intestinal morphology. Importantly, no statistically significant differences were detected between the 6% group and its adjacent dose groups (3% and 9%) for the majority of key indicators. As a result, including the 6% group data did not provide additional scientific insight or change the overall dose-response trend, but rather led to visual redundancy and increased complexity in data presentation without contributing new information. Therefore, to improve the clarity and conciseness of the manuscript, and to focus the reader’s attention on the most informative dose levels (0% control, low: 3%, medium: 9%, and high: 12%), we decided to exclude the 6% group from the final version of the tables and figures. This decision was based solely on scientific presentation considerations, not on data manipulation or selective reporting. The complete dataset, including the 6% group, is available from the corresponding author upon reasonable request.

• Comment 2

There is no explanation: a) why is ADG decreasing at 2.86% (Table 2. from 14.32 g in the control group till 13.91 g in the group fed with 12% SPTM addition) , b) why, at the same time ADFI is increasing from 86.56 g till 87.54 g.( see Table 2). It looks like chicken are eating more, but have less relative growth dynamics, that is negative result.

Response: Thank you for this insightful comment. We agree that the numerical decrease in ADG and increase in ADFI deserve further consideration, even though these differences were not statistically significant (P > 0.05). Therefore, we have expanded the Discussion section to address this trend. We now suggest that the slightly higher feed intake may reflect compensatory consumption associated with the higher fiber content and different carbohydrate characteristics of SPTM. Additionally, because birds were in the late fattening stage, a greater proportion of dietary energy may have been partitioned toward lipid deposition rather than body weight gain, which is consistent with the increased intramuscular fat content observed in the higher SPTM groups. However, these interpretations remain speculative because no digestibility or energy utilization measurements were conducted. In response to the reviewer's comment, we have added additional discussion regarding this observation in the revised manuscript. The corresponding revisions are highlighted in yellow in the Discussion section for clarity and ease of review.

• Comment 3

It is also strange that the difference between final and initial body weight (divided by 40 days) is giving another ADG value in my calculation as compared to the Table 2 (presented in the appropriate column in the table 2, page 6).

Response: Thank you for the reviewer’s careful evaluation and calculations. Following this comment, we thoroughly rechecked the original dataset and verified the calculation method used for average daily gain (ADG). During this process, we identified inaccuracies in the calculated values. Therefore, ADG and the feed-to-gain ratio (F/G) were recalculated using the original data, and the corrected values have been updated throughout the revised manuscript.

• Comment 4

There is no explanation, why is “leg or breast muscle weight” decreasing by addition of 3% and 6% SPTM at about 7.66% or 11.16%, as well as becoming almost the same as for control group by 12% SPTM addition. see Table 3 .

Response: We appreciate this important observation. However, we would like to clarify that the leg muscle percentage and breast muscle percentage values presented in Table 3 showed no statistically significant differences among any groups (P > 0.05). The numerical fluctuations (e.g., breast muscle percentage: 16.58%, 14.73%, 15.89%, 16.40% for 0%, 3%, 9%, 12% respectively) are within the expected biological variation and are not statistically meaningful. Therefore, we cannot conclude that leg or breast muscle weight decreased with 3% or 9% SPTM, as the observed differences are not significant.

• Comment 5

There is no explanation, why heart , spleen, by 33.04%, gizzard and liver, 9.03%, indexes are little bit increasing, whereas stomach and proventriculus are slightly decreasing. see Table 4.

Response: As with Comment 4, we have re-examined Table 4. All organ indices (heart, liver, stomach, gizzard, proventriculus, spleen) showed no statistically significant differences among any treatment groups (P > 0.05). The numerical percentage changes noted by the reviewer reflect within-group variation and are not statistically meaningful. In the absence of significant differences, providing biological explanations for these numerical trends would be speculative and inappropriate. 

• Comment 6

There is no explanation, why are the key biochemical parameters of chicken blood serum (see Tables 5 and 6) different from those, published by many other researchers, as well as  the nutrient composition of breast and leg muscle. see Tables 10 and 11.

Response: Thank you for this valuable comment. We agree that the absolute values of serum biochemical parameters and muscle nutrient composition may differ from those reported in other studies. Such differences are common in poultry research and may be attributed to several factors, including genetic background, age, feeding strategy, environmental conditions, sample collection procedures, and analytical methodologies. In the present study, Wenchang chickens, a slow-growing indigenous Chinese breed, were used during the late fattening period (81-120 d of age). Previous studies have demonstrated that indigenous chickens differ substantially from commercial broilers in nutrient metabolism, blood biochemical profiles, muscle composition, and fat deposition patterns. In addition, serum biochemical indices are known to be influenced by physiological status, diet composition, sampling time, and assay methods. Similarly, the nutrient composition of breast and leg muscles can vary depending on genotype, age at slaughter, feeding regime, and muscle type. Breast and leg muscles differ markedly in fiber-type composition and metabolic characteristics, which may result in different protein, lipid, and moisture contents. Therefore, direct comparison of absolute values among studies should be interpreted with caution.

• Comment 7

There is no explanation why total amount of amino acids is decreasing by increasing SPTM addition, from 3% to 12%, in the breast and leg muscle at 12.31% and 10.43%, respectively. It looks like by adding of the SPTM, the quality of chicken meat is getting worse and worse. see Table 12 and 13.

Response: We agree with the reviewer that this is a critical observation. Indeed, our data show that 12% SPTM significantly reduced total amino acids, essential amino acids, and umami amino acids in breast muscle compared to lower inclusion levels. This indicates that high-level SPTM (12%) may negatively affect protein deposition or amino acid profiles in breast muscle. We will revise the manuscript substantially to reflect this finding: (1) In the Abstract and Conclusion, we will remove any claim that 9-12% SPTM improved nutrient composition; (2) In the Results, we will clearly state the negative effects at 12%; (3) In the Discussion, we will offer potential explanations: the lower crude protein content of SPTM (4.36%) compared to corn, possible amino acid imbalance, or anti-nutritional factors (e.g., trypsin inhibitors) that may reduce protein digestibility at higher inclusion levels.

• Comment 8

It's important to withdraw the column average fiber area from the table 17, because there are only zero values.

Response: We agree completely. The values for average fiber area in Tables 16 and 17 were originally reported in mm² with insufficient decimal places, resulting in "0.00" values. We have since converted the unit to µm² and reported values with appropriate precision. Therefore, the corrected Tables 16 and 17 will no longer contain meaningless zero values. We thank the reviewer for emphasizing this correction.

• Comment 9

There almost no discussion about all these points (in the row from 1 to 7) in the part 3. “Discussion”.

Response: We acknowledge this serious deficiency in the original manuscript. In the revised version, we will significantly expand the Discussion to address each of the points raised by the reviewer. Specifically, we will add integrated paragraphs discussing, with all modifications highlighted in yellow for your convenience, please see line 427-438 of revised manuscript.

• Comment 10

The part “Conclusions” is too short. The particular application of 9% or 12% SPTM addition (mentioned by the authors as one data interval : “9% -12% SPTM” at line 457) must be proved and mentioned separately , not as the one data interval.

Response: We agree fully. In the revised Conclusion, with all modifications highlighted in yellow for your convenience, please see line 529-534 of revised manuscript.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Accept in present form

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have done a great job of improving the present manuscript " Effects of dietary sweet potato tuber meal on production performance, meat quality and intestinal health of Wenchang chickens" (biology-4362872).  The aim of the manuscript is "to investigate the effects of dietary supplementation” with sweet potato tuber meal (SPTM) on growth and slaughter performance, physiological and biochemical parameters “of 81-day-old female Wenchang chickens”. The present manuscript is actual and important in the field of the poultry biology and husbandry.  It is positive that the authors have revised a number of tables (1,2,13-17) and have rewritten all sections, especially the sections: “Results,” “Discussion,” and “Conclusion”. The authors have revised the line “Note：” at the Page 13, line 411 (‘Five random fields per section at 400× magnification. Tissue sections were prepared and stained with H&E”) to the Figure 1. (“Breast muscle (A) and thigh muscle (B) histological characteristics, scale bar: 20 µm”). All these changes are positive and important. This manuscript is scientifically sound and it experimental design is appropriate to test the author’s hypothesis. All the tables and the figure 1 are appropriate and properly show the data. The data is interpreted appropriately and consistently throughout the manuscript. The statistical analysis of the data acquired are correct. The ethics statements and data availability statements are adequate. There are no essential comments on the scientific part of this manuscript, as well as - no technical remarks.

I think the article has been rewritten enough and can be accepted in present form.