Supplementation of Microbial and Fungal Phytases to Low Protein and Energy Diets: Effects on Productive Performance, Nutrient Digestibility, and Blood Profiles of Broilers

Round 1

Reviewer 1 Report

Page. 1, row 18 - isocaloric vs. isocaliric

Page 3: If you intend to use the abbreviations in the tables, please provide the abbreviations for each parameter analyzed (in parentheses) in the material and method section. For example, in section 2.1 provide the abbreviation for conversion ratio of protein and energy. In section 2.2 provide abbreviations for abdominal fat and include the formula for the production index (PI).

Statistical analysis of data is not presented! Please provide a detailed paragraph.

Page 5, table 2: Please explain what PCR and ECR mean in the table legend.

Page 7. Row 200: The expression of parameters must be uniform, so you do not abbreviate the AST parameter.

Table 2: In the column 5 (energy intake), in the row with interaction diet x phytase revise the superscripts, because ,,b’’ is missing.

Table 2 legend: The superscripts ,,d,e’’ are missing from table legend. Please insert them.

Author Response

Reviewer 1

Page. 1, row 18 - isocaloric vs. isocaliric

Au: done

Page 3: If you intend to use the abbreviations in the tables, please provide the abbreviations for each parameter analyzed (in parentheses) in the material and method section. For example, in section 2.1 provide the abbreviation for conversion ratio of protein and energy. In section 2.2 provide abbreviations for abdominal fat and include the formula for the production index (PI).

Au: done

Statistical analysis of data is not presented! Please provide a detailed paragraph.

Au: you are right! Somewhat happened during submission and the paragraph disappeared…I added, thank you very much.

Page 5, table 2: Please explain what PCR and ECR mean in the table legend.

Au: done

Page 7. Row 200: The expression of parameters must be uniform, so you do not abbreviate the AST parameter.

Au: done

Table 2: In the column 5 (energy intake), in the row with interaction diet x phytase revise the superscripts, because ,,b’’ is missing.

Au: corrected

Table 2 legend: The superscripts ,,d,e’’ are missing from table legend. Please insert them.

Au: corrected

Reviewer 2 Report

The presented contribution is interesting because it is enlarging the knowledge about the application of phytase in poultry feeding, a topic that has been monitored for a long time.
The authors present several results on production parameters, biochemical parameters and the quality of poultry products.
Comments and recommendations:
The self-citation with serial number 20 in references is not used appropriately. The discussion refers to the digestibility of nutrients of poultry, but according to the title, the work is focused on rabbits.
I recommend expressing the metabolizable energy (ME) in MegaJoules (MJ) with the conversion factor 1 cal = 4.1868 joules in table no. 1.
The number format should be unified (2947 ... 3,023 ...) in the ME line. Create the list of the abbreviations used (SAA, Av. P., NFE, ...) in the description below the table.
According to the methodology, the mortality was monitored daily. The mortality, the number of dead animals in the groups, is mentioned in table no. 2 in the last column. The results and discussions lack a description of when the mortality was observed and its cause.
In connection with the mortality, I perceive statements with some uncertainty about lower feed consumption in the experimental groups compared to the control group. The mortality was observed only in the experimental groups (from 1 to 3 pieces), the control group was absent from the mortality. Therefore,  it is logical that in the group with a lower number of individuals there had to be lower feed consumption. The feed conversion coefficient was higher in the experimental groups compared to the control by 0.01 - 0.04. It is the reason for higher feed consumption per unit of production. It needs to be better discussed.
In connection with the above mentioned, it is necessary to explain in more details the claim about reducing feed costs which is the savings associated with lower feed consumption, or lower prices of feed with lower nutritional value.
In table no. 2 in the Feed Intake column in the FP row, it is important to correct the data and describe the abbreviations used (FCR, PCR, ECR) below the table.
It is required to modify the columns so that the names of organs are not divided in table no. 4.
The levels greater than 0.05, 0.01, or 0.001 are reported for statistical significance.
I did not encounter the expression of statistical significance at the level of 0.03. or 0,005.
In addition to the other benefits mentioned in the present article, a decrease in the nitrogen content in the faeces is also found. I consider this to be a very important finding concerning the ruduction of the environmental burden. And I recommend that it be stated and emphasized in the conclusions as well.

Author Response

Reviewer 2

The presented contribution is interesting because it is enlarging the knowledge about the application of phytase in poultry feeding, a topic that has been monitored for a long time. The authors present several results on production parameters, biochemical parameters and the quality of poultry products.

Au: thank you very much for your comment

Comments and recommendations:
The self-citation with serial number 20 in references is not used appropriately. The discussion refers to the digestibility of nutrients of poultry, but according to the title, the work is focused on rabbits.

Au: the right citation has been added and the wrong deleted

I recommend expressing the metabolizable energy (ME) in MegaJoules (MJ) with the conversion factor 1 cal = 4.1868 joules in table no. 1. The number format should be unified (2947 ... 3,023 ...) in the ME line. Create the list of the abbreviations used (SAA, Av. P., NFE, ...) in the description below the table.

Au: done

According to the methodology, the mortality was monitored daily. The mortality, the number of dead animals in the groups, is mentioned in table no. 2 in the last column. The results and discussions lack a description of when the mortality was observed and its cause.  

AU: Added

In connection with the mortality, I perceive statements with some uncertainty about lower feed consumption in the experimental groups compared to the control group. The mortality was observed only in the experimental groups (from 1 to 3 pieces), the control group was absent from the mortality. Therefore, it is logical that in the group with a lower number of individuals there had to be lower feed consumption. The feed conversion coefficient was higher in the experimental groups compared to the control by 0.01 - 0.04. It is the reason for higher feed consumption per unit of production. It needs to be better discussed.

Au: It should be mentioned that, the feed intake was corrected for differences in mortality among pens and treatments and thus the FCR was based corrected/actual feed consumption among the experimental treatments. However, there still in-avoided case which can’t be corrected such as variation in spaces allowance and thus birds activity and it is effect on energy expenditure and increasing feeding space in the pens.  Added to the text.

In connection with the above mentioned, it is necessary to explain in more details the claim about reducing feed costs which is the savings associated with lower feed consumption, or lower prices of feed with lower nutritional value.

Au: done

In table no. 2 in the Feed Intake column in the FP row, it is important to correct the data and describe the abbreviations used (FCR, PCR, ECR) below the table.

Au: done

It is required to modify the columns so that the names of organs are not divided in table no. 4.

Au: done

The levels greater than 0.05, 0.01, or 0.001 are reported for statistical significance.
I did not encounter the expression of statistical significance at the level of 0.03. or 0,005.

Au: corrected

In addition to the other benefits mentioned in the present article, a decrease in the nitrogen content in the faeces is also found. I consider this to be a very important finding concerning the ruduction of the environmental burden. And I recommend that it be stated and emphasized in the conclusions as well.

Au: thank you for your comment, a period has been added in the conclusions

Reviewer 3 Report

Present article: Supplementation of microbial and fungal phytases to low protein and energy diets: effects on productive performance, nutrient digestibility, and blood profiles of broilers, is actual and discusses current issues of broiler chicken nutrition.

I have minor comments and suggestions for authors:

row 102 - light:dark cycle (23:1) - was this ratio correct ? From my point of view the  23: 1 ratio is unsuitable for one-day-old chickens; was the light regime set for the given breed of broiler chickens? Was this ratio set according to recommendations by producer Sasso strain?

row 106-111- Would it not be appropriate to select and label a random sample of broilers for which you would observe weekly growths during the experiment?

row 114- why males only ? In your experiment males/females were in 1:1 sex ratio ? 

Table 1 - please explain SAA and NFE shortcuts under the table

Table 6 - How can you explain TL increase in Low-CP group ?

row 229 - Does the sex of the broiler may change the nitrogen content in excreta ?

How can you explain the effect of A.niger on the abdominal fat depossion ?

Overall, the article: Supplementation of microbial and fungal phytases to low protein and energy diets: effects on productive performance, nutrient digestibility, and blood profiles of broilers; as useful for practical use.

Author Response

Reviewer 3

Present article: Supplementation of microbial and fungal phytases to low protein and energy diets: effects on productive performance, nutrient digestibility, and blood profiles of broilers, is actual and discusses current issues of broiler chicken nutrition.

Au: thank you for your comment

I have minor comments and suggestions for authors:

row 102 - light:dark cycle (23:1) - was this ratio correct ? From my point of view the  23: 1 ratio is unsuitable for one-day-old chickens; was the light regime set for the given breed of broiler chickens? Was this ratio set according to recommendations by producer Sasso strain?

Au: I agree, but this used in this area to increase feed consumption during the light period.

row 106-111- Would it not be appropriate to select and label a random sample of broilers for which you would observe weekly growths during the experiment?

Au: probably yes, but we described the experimental procedure followed in our trial

row 114- why males only ? In your experiment males/females were in 1:1 sex ratio?

Au: males are usually used in digestibility traits to avoid the confound effect of sex on digestibility of nutrients.

Table 1 - please explain SAA and NFE shortcuts under the table

Au: done

Table 6 - How can you explain TL increase in Low-CP group ?

Au: the increase is not statistical significant, so we did not discussed in the manuscript. The increase is little. However, this could be due to metabolic changes in poultry fed low-CP diet

row 229 - Does the sex of the broiler may change the nitrogen content in excreta ?

Au: Thank you for your comment. This point could be assessed in further trials. We did not include the sex in our statistical model

How can you explain the effect of A.niger on the abdominal fat depossion ?

Au: there are not statistical differences in due to different kind of phytase.

Overall, the article: Supplementation of microbial and fungal phytases to low protein and energy diets: effects on productive performance, nutrient digestibility, and blood profiles of broilers; as useful for practical use.

Au: thank you for your comment.