Dietary Supplementation with Different ω-6 to ω-3 Fatty Acid Ratios Affects the Sustainability of Performance, Egg Quality, Fatty Acid Profile, Immunity and Egg Health Indices of Laying Hens

Round 1

Reviewer 1 Report

The current research evaluated the effects of dietary supplementation with different ω-6 to ω-3 fatty acid ratios on productive performance, egg quality, fatty acid profile, immunity, and egg health indices of laying hens. Considering the bird and ultimately the human health aspects of the issue assessed, this is a significant research topic although it is not novel but still worth to probe. However, they are some questions need the author to resolve and supplement. The following recommendations are for reference only.

First of all, though the information has some novelty and quite interest for an international journal, however, my main concern is related to this study novelty - it must be clearly indicated where is a progress in comparison to other reports. Decades of scientific research has improved our understanding of the application of supplemental fats with different ω-6 to ω-3 fatty acid ratios in the feeding of layer hens and their relevance on health, productivity and egg fatty acid profile and oxidative status in serum, liver, muscle, spermatozoa and eggs as well.  These were documented in many comprehensive reviews and experimental studies even taking into account the genotype and age of the hen and diet energy level. The statement by the authors that  “ keeping in mind the importance of the ratio ω-6 to ω-3 and its role in immunity and disease prevention , the present study aimed to test the dietary impact of different ω-6/ω-3 PUFAs on performance, egg quality, egg fatty acid profile” is far below expectation and not satisfying. Instead the authors should fore front their efforts on egg health indices with altered dietary ω-6 to ω-3 ratios.

By means of shortcomings with material-methods, first and foremost, the productive performance of the hybrid layer hen genotype (Lohmann LSL) used is substantially lower than the objectives published in their management guide and the field experiences-observations with this strain!!  This is very intriguing that this hybrid maintains outstanding and consistent performance at any management procedure. The LSL management guide indicates that, between 50 to 58 wk of age, hens perform 92 % egg production rate, 65 g egg weight, 60 g egg mass when offered the diet having specifications as presented in this study (HR diet). It is interesting that only 10-20 g   increases in body weight gain during 8 wk accompanies to such performance output providing that to consume 115 g feed intake per day. However, in the present experiment, hens gain 153-173 g body weight during 8 wk experimental period, which is impossible for any commercial layer hen strain while consuming 115 g regular laying hen diet per day. Another inadequacy that the authors tries to explain 15 g difference in BWG between HR and MR birds with “obesity” which is an inaccurate description. This clearly show that there are serious problems with the management and even general health status of the birds even recommended amount of feed ingested by them !!.   This necessitates rigorous and plausible explanations.

The paper also suffers some major fails in the understanding of the statistical significance. Although P value for survival rate is far from the significance (P= 0.321), the authors interpreted the results in favour of MR and HR treatments. This is a scientifically incorrect approach. Hence, please omit all the comments made between Lines 455 and 462 from the text.

Additional interpretations are needed in regard to increased yolk colour score with MR and HR treatments. The positive effects of dietary fatty acids on carotenoid absorption in the intestines could be further added to the text by using the appropriate references in the scientific literature. 

In general, the study with satisfying   data, proper design and precise analytical measurements and performance observations. The interpretations and conclusions are quite sound, proofed by the data and consistent with the   objectives. Briefly, the interpretations have been done with sufficient rigour to justify the conclusions. However, as outlined below, there few items that need to be revised to improve it further. 

 

 

Author Response

The current research evaluated the effects of dietary supplementation with different ω-6 to ω-3 fatty acid ratios on productive performance, egg quality, fatty acid profile, immunity, and egg health indices of laying hens. Considering the bird and ultimately the human health aspects of the issue assessed, this is a significant research topic although it is not novel but still worth to probe. However, they are some questions need the author to resolve and supplement. The following recommendations are for reference only.

RE: Thank you very much, I appreciate your encouragements, suggestions  and comments.

First of all, though the information has some novelty and quite interest for an international journal, however, my main concern is related to this study novelty - it must be clearly indicated where a progress is in comparison to other reports. Decades of scientific research has improved our understanding of the application of supplemental fats with different ω-6 to ω-3 fatty acid ratios in the feeding of layer hens and their relevance on health, productivity and egg fatty acid profile and oxidative status in serum, liver, muscle, spermatozoa, and eggs as well. These were documented in many comprehensive reviews and experimental studies even considering the genotype and age of the hen and diet energy level. The statement by the authors that “keeping in mind the importance of the ratio ω-6 to ω-3 and its role in immunity and disease prevention, the present study aimed to test the dietary impact of different ω-6/ω-3 PUFAs on performance, egg quality, egg fatty acid profile” is far below expectation and not satisfying. Instead, the authors should fore front their efforts on egg health indices with altered dietary ω-6 to ω-3 ratios.

RE: The objective was revised according to the review comments.

By means of shortcomings with material-methods, first and foremost, the productive performance of the hybrid layer hen genotype (Lohmann LSL) used is substantially lower than the objectives published in their management guide and the field experiences-observations with this strain!!  This is very intriguing that this hybrid maintains outstanding and consistent performance at any management procedure. The LSL management guide indicates that, between 50 to 58 wk of age, hens perform 92 % egg production rate, 65 g egg weight, 60 g egg mass when offered the diet having specifications as presented in this study (HR diet). It is interesting that only 10-20 g   increases in body weight gain during 8 wk accompanies to such performance output providing that to consume 115 g feed intake per day. However, in the present experiment, hens gain 153-173 g body weight during 8 wk experimental period, which is impossible for any commercial layer hen strain while consuming 115 g regular laying hen diet per day. Another inadequacy that the authors tries to explain 15 g difference in BWG between HR and MR birds with “obesity” which is an inaccurate description. This clearly show that there are serious problems with the management and even general health status of the birds even recommended amount of feed ingested by them!!.   This necessitates rigorous and plausible explanations.

RE: This was addressed in the M&M section and in the discussion section.

The paper also suffers some major fails in the understanding of the statistical significance. Although P value for survival rate is far from the significance (P= 0.321), the authors interpreted the results in favour of MR and HR treatments. This is a scientifically incorrect approach. Hence, please omit all the comments made between Lines 455 and 462 from the text.

RE: Deleted

Additional interpretations are needed regarding increased yolk colour score with MR and HR treatments. The positive effects of dietary fatty acids on carotenoid absorption in the intestines could be further added to the text by using the appropriate references in the scientific literature. 

RE: Done

In general, the study with satisfying   data, proper design and precise analytical measurements and performance observations. The interpretations and conclusions are quite sound, proofed by the data and consistent with the objectives. Briefly, the interpretations have been done with sufficient rigour to justify the conclusions. However, as outlined below, there few items that need to be revised to improve it further.

RE: Thank you very much for your positive opinion on our paper.

Reviewer 2 Report

The manuscript entitled "Dietary supplementation with different ω-6 to ω-3 fatty acid ratios affects sustainability of performance, egg quality, fatty acid  profile, immunity, and egg health indices of laying hens " does have some novelty and can be published once the specific comment made below and on the attached manuscript is revised. 

English correction to be made throughout the manuscript. Please revise throughout. I recommend English editing. eg. Lines 18, 

Line 20 and throughout the manuscript: The actual ratios should be given. Eg. 16.7:1, 9.3:1, 5.5:1 respectively.

Line 22 and throughout the manuscript: When the term 'significant' is used throughout the manuscript the  actual p value can be provided in brackets. 

Line 55: The number of carbons and double bonds will further highlight the length of the carbon chain being described

Line 82: What determined the various ratios of w-6/w-3 PUFA in the experiment. Please provide some justification. As stated in the introduction the ideal ratio is between 1:1 to 5:1. 

Line 95: Please revise this reference into the journal format.

Table 1: This should be revised. The superscript of numeric values on the kg seems to express an inaccurate unit of measure. Please revise throughout the table. (TABLE 1)

Line 182: The blood tubes used to collect the blood should be stated and the panel that will be used on the blood. eg. Complete blood count, Serum biochemistry etc?

Line 209-210: Is this a correct statement based on what is presented in table 2?

Lines 457-458; These results were not stated in the results section. Then how can it be discussed in this section. Please revise and place survival rate data based on the three diets. 

Line 460: Attia et al. is only ref. no. 37 and 38. Please rephrase appropriately.

Comments for author File: Comments.pdf

Author Response

The manuscript entitled "Dietary supplementation with different ω-6 to ω-3 fatty acid ratios affects sustainability of performance, egg quality, fatty acid profile, immunity, and egg health indices of laying hens " does have some novelty and can be published once the specific comment made below and on the attached manuscript is revised. 

RE: Thank you very much for your positive opinion on our paper.

English correction to be made throughout the manuscript. Please revise throughout. I recommend English editing. eg. Lines 18, 

RE: The English language has been checked by an expert. 

Line 20 and throughout the manuscript: The actual ratios should be given. Eg. 16.7:1, 9.3:1, 5.5:1 respectively, Revised

Line 22 and throughout the manuscript: When the term 'significant' is used throughout the manuscript the actual p value can be provided in brackets. 

RE: Thanks for your suggestion; however, we believe that the significant level reported in tables may be adequate. 

Line 55: The number of carbons and double bonds will further highlight the length of the carbon chain being described

RE: Added

Line 82: What determined the various ratios of w-6/w-3 PUFA in the experiment. Please provide some justification. As stated in the introduction the ideal ratio is between 1:1 to 5:1.

RE: It was provided.

Line 95: Please revise this reference into the journal format.

RE: Done

Table 1: This should be revised. The superscript of numeric values on the kg seems to express an inaccurate unit of measure. Please revise throughout the table. (TABLE 1)

RE: Thanks so much for your precious comments; we have revised the Table accordingly.

Line 182: The blood tubes used to collect the blood should be stated and the panel that will be used on the blood. eg. Complete blood count, Serum biochemistry etc?

RE: Done

Line 209-210: Is this a correct statement based on what is presented in table 2?

RE: It was revised

Lines 457-458; These results were not stated in the results section. Then how can it be discussed in this section. Please revise and place survival rate data based on the three diets.

RE: Done

Line 460: Attia et al. is only ref. no. 37 and 38. Please rephrase appropriately

RE: Corrected

Reviewer 3 Report

Dear authors, I am sending you some notes:

Introduction

Line 50  - The sentence about Covid-19 is not related to the topic of the article

Line 53 – 60 - It would be more appropriate to add a few sentences focused directly on the effect of acids on poultry instead of the general effect on the human body

the conclusion could include more recommendations in this direction.

Author Response

Introduction

Line 50  - The sentence about Covid-19 is not related to the topic of the article

Au: the sentence has been deleted

Line 53 – 60 - It would be more appropriate to add a few sentences focused directly on the effect of acids on poultry instead of the general effect on the human body

Au: Two sentences have been added focused on the effect of omega-3 and omega-6 PUFA on poultry.

the conclusion could include more recommendations in this direction.

Au: conclusions have been modified

Round 2

Reviewer 2 Report

All revisions were made and where revisions were not made proper justifications were provided. 

Author Response

Thank you very much for your valuable review.