The Effect of Humic Substances on the Meat Quality in the Fattening of Farm Pheasants (Phasianus colchicus)

Round 1

Reviewer 1 Report

The reviewed manuscript evaluated the effect of different levels of humic acid (HA) on carcass parameters, chemical composition and fatty acids profile of meat in pheasants fatted up to 90 days of age.

The manuscript has serious flaws:

Keywords: ......, amino acids, .... The manuscript did not provide information about the amino acids profile of pheasants meat!

Introduction

The introduction did not provide a quite comprehensive state-of-the-art supported by relevant references, only a short paragraph about the use of HA in poultry ”HA is widely used as an alternative growth promoter for antibiotics in improving bird performance and health [15-19]. Some studies investigated the effect of using HA as growth promoter in poultry and obtained positive results [20-22].”

The authors write that „The research hypothesis was that addition of the humic substances increase the performance of the pheasants as well as the meat quality.”, but the article did not provide the performance results of the pheasants as an effect of the addition of HA.

Materials and Methods

Feeding

„Totally 200 one-day-old pheasants were used, housed in groups of 50 per pen, and assigned to four treatments: 1 = basal diet without humic acids, 2 = basal diet with 0.50% humic acids in feed mixture, 3 = basal diet with 0.75% humic acids in feed mixture and 4 = basal diet with 1.00% humic acids in feed mixture, respectively.”

The size group of 50 pheasants per pen, with no information about the number of replicate pens per group and the sex proportion of pheasants per group, is not sufficient to draw conclusions about the carcass and meat  quality traits.

Tables 1 and 2: the diets were not isonitrogenous, especially the grower diets.

Sampling and laboratory analysis

The methods of laboratory analysis are not well described, the fatty acids analyses of meat are missing as well as the energy value calculations.

Results

Tables 3 to 7: The significance letters/superscripts are not correctly given.

Author Response

• from keywords have been deleted "amino acids",
• the authors completed the introduction and modified the research hypothesis in the context of the manuscript,
• The experiment was realized to find out the effect of adding an additive to the feed mixtures and the subsequent effect on fattening pheasants. The experiment was not realized with the aim of partial or complete nutrient replacement in feed ingredients.
• totally 200 one-day-old pheasants were used, housed in 4 groups of 50 per pen (one group consisted of 10 pieces, with 5 replications), and assigned to four treatments: 1 = basal diet without humic acids, 2 = basal diet with 0.50% humic acids in feed mixture, 3 = basal diet with 0.75% humic acids in feed mixture and 4 = basal diet with 1.00% humic acids in feed mixture, respectively,
• the authors completed the methods of laboratory analysis,
• the significance letters/superscripts are correctly given.

Author Response File: Author Response.docx

Reviewer 2 Report

Introduction

L34 Please, explain better and include adequate references showing results of consumers.

L34-39 In my opinion this whole paragraph needs to be reviewed. I see sentences disconnected.

Suggestion: 1) show numbers of production (and some relevant  comments, such as where it is produced, if it is growing the production…) 2) how is it produced 3) the main destination of the production and the value for them-

L40-54 I think that the second paragraph needs a connection with the first.

Say something regarding the problem that can be solved by humic substances and then explain why it can help and what other studies have found.

Material and methods

Please, include information about where came from the humic acids.

L72 what was the initial weight per treatment?

L91 Could you explain further how did you select those 10 animals?

Results

L119 in all carcass traits?

L145 p or P? Please, standardize

Discussion

Are results from the animal performance published? Maybe they can mentioned in the introduction or in the discussion section

L179-184 but what is the characteristic of the HS used?

L179-205 In my opinion, this section is difficult to read. The second paragraph is just what other papers found and the first and the third are explanation but disconnected. I think it has to be integrated to be more interesting to read. Why some papers agree or disagree with the findings in this manuscript.

L211 what does it mean “improve meat quality”

L213-215 I don´t understand well this sentence. HS increased protein and fat? So, the control has more water?

L218 and L219-220 What do you mean by improving meat quality? Meat quality could mean many things, so you need to specify.

L227-230 Was that also found in the present study?

L237-238 I do not see that in the results

Author Response

• In Slovakia, pheasant fattening is not realised. Our manuscript is preliminary study. In our opinion, there are no relevant pheasant meat consumption values in Slovakia. Pheasants that have been killed on hunts are offered on the market.
• the authors completed the introduction and modified the research hypothesis in the context of the manuscript,
• totally 200 one-day-old pheasants were used, housed in 4 groups of 50 per pen (one group consisted of 10 pieces, with 5 replications), and assigned to four treatments: 1 = basal diet without humic acids, 2 = basal diet with 0.50% humic acids in feed mixture, 3 = basal diet with 0.75% humic acids in feed mixture and 4 = basal diet with 1.00% humic acids in feed mixture, respectively,
• the authors completed the methods of laboratory analysis,
• birds for meat quality analysis were selected as representative sample,
• the significance letters/superscripts are correctly given,
• the authors removed the parts from the discussion that were not related to the objective of the work.

Author Response File: Author Response.docx

Reviewer 3 Report

Manuscript ID: agriculture-2135178

Title: The Effect of Humic Substances on the Meat Quality in the Farm Pheasants (Phasianus colchicus) Fattening

The manuscript needs some modifications so that it could be better than before. It would be helpful if the authors would consider the following points:

- Improve the introduction section, providing the problem

- References used should be updated, where it is noted (no reference in 2022, one reference in 2021 and one reference in 2020)

- Why is the percentage of crude protein in the starter and grower diets uneven between groups?

- A table must be added containing the proportions of Ingredients used in the formation of diets

- In Tables 1 and 2: Please show " Nutrients composition" is analyzed or calculated

- In Tables 3-7: Add column contains P-value

- The discussion section needs strengthening. The authors should discuss the results clearly and should provide relevant information

- Line 20: Change "birds were fed with diets" to " birds were fed diets"

-Linse23-24: Rewrite this sentence

- Line 25: Change " The same effect of ………………… were found" to " The same effect of ………………… was found"

- Line 56: Change " the 90 day " to " 90 days "

- Lines 57, 219, 245: Add "the" before " addition"

- Line 57: Change " increase" to " increases"

- Line 80: Change " Table 1 and 2" to " Tables 1 and 2"

- Lines 83-84: Explain what is meant by this abbreviation " min."

- Line 94: Add "the" before " weight "

- Line 101: Add "the" before " slaughter "

- Line 101: Change " in 90th days " to " at 90 days "

- Line 104: Add "the" before " Content "

- Line 104: Change " drying of " to " drying "

- Line 106: Add "to" after " according "

- Line 119: Add "an" before " effect "

- Line 121: Add "of" before " body"

- Line 124: Add "the" before " proportion"

- Line 121: Add "of" before " internal organs"

- Line 130: Change " significantly affect " to " a significant effect "

- Lines 162, 187, 216, 218: Add "the" before " control "

- Line 163: Add "an" before " insignificant effect"

- Line 186: Add "a" before " significant increase"

- Lines 186-187: Add "a" before " significant decrease"

- Line 194: Delete "of"

- Line 195: Change " a diets" to " diets" or " a diet"

- Lines 201-202: Rewrite this sentence

- Line 210: Add "and" before " crude"

- Line 215: Change " Feeding diet with" to " Feeding a diet containing"

- Line 216: Add "the" before " basal diet"

- Line 217: Delete "of"

- Line 218: Rewrite this sentence

- Line 225: Change "related with" to " related to"

- Lines 226, 237: Add "the" before " inclusion "

- Lines 227-230: Rewrite this sentence

- Line 238: Add "the" before " maintenance "

- Line 242: Add "a" before "dose "

- Line 243: Add "the" before "lower dose "

- Line 317: Delete this line

- Insert the correct format style for journal in the references in the text and references list.

Author Response

• the literature was supplemented by new authors,
• the authors completed the introduction and modified the research hypothesis in the context of the manuscript,
• proportions of ingredients used in the formation of diets  were not provided by the producer,
• " Nutrients composition" is analyzed,
• the authors completed the methods of laboratory analysis,
• the significance letters/superscripts are correctly given,
• the authors accepted specific comments on the level of the English language.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Even though the Introduction and Materials and Methods sections were updated, the obtained results are not sufficient to draw conclusions about the carcass traits and meat quality (chemical composition and fatty acids profile).

The manuscript still has serious flaws: 

Results

Line 150-151: „Male, as well as female pheasants, fed the 1.0 HS diets were typical with the lowest weight of abdominal fat in comparison with other groups.”

I disagree; according to the results given in Table 3, the lowest abdominal fat weight was achieved by the 0.5% HS group.

Line 162-163: „The application of HS in pheasant broiler diets significantly decreased the fat content (P< 0.05) in breast muscle.”

I disagree; the Table 4 results show a significant decrease only in groups 0.50 and 0.75 HS, like in thigh muscle (Table 5).

Table 6: Fatty acids in breast muscle samples: The significance superscripts are missing in Stearic acid in female breast muscle.

Line 183-184: “A tendency (P > 0.05) of higher PUFA content was found in group 0.50 HS in breast muscles.” Why did authors note the tendency as significant differences in Table 6?

Discussion

Line 229-231: “The supplementation of pheasant’s diet with dietary natural and acidified HS resulted in statistical differences in the following measured parameters of breast meat samples: dry matter, water, crude fat, and crude proteins (p < 0.05).” This are not true! Table 4 shows differences only in crude protein and fat content.

Line 237-239: „However, chicks fed the basal diet supplemented with 0.1 % of humic acid had significantly lower fat than other supplements and control group.” The affirmation is not supported by the results from Tables 4 and 5.

Conclusions

Line 261-267: „We may conclude that HS supplementation at dose of 0.50 and 0.75% provided through feed improved weights of carcass body parts of broiler pheasants. HS supplementation at a dose of 1.00% reduced carcass body parts weights and increased abdominal fat weight compared with the lower dose of HS in diets. Following the our scientific hypothesis about the effect of HS on meat quality, we found, that HS supplementation at 0.50 and 0.75 affected nutrient characteristics in breast and thigh muscles. However, fatty acids content in muscles had not affected by addition of HS in diets.”

The conclusion did not reflect the study results.

Author Response

We accepted the reviewer's comments.

Reviewer 2 Report

Improvements have been made, but I found responses very generic and some questions/comments were not replied or not replied with detail/care.

Introduction

The introduction has improved with the additions, but the first sentence was not revised:

L35 “The meat of pheasant (Phasianus colchicus) is one of the most valued by consumers [1].”

I am not sure if the sentence is correct, the reference does not show results from consumers. So, delete or include adequate references. 

Material and methods

Information about the origin of HS has been added, but other questions were not properly replied.

What was the initial weight per treatment?

Could you explain further how did you select those 10 animals?  Saying that are representative is not informative.

It would be interesting to include the final live weight of the animals.

Discussion

Please, respond point by point made in the first round.

I only see an improvement in the discussion by deleting some sentences (I agree in the removal of some), but the discussion is not yet satisfactory.

Author Response

We accepted the reviewer's comments.