Effects of Diets with Varying Astaxanthin from Yarrowia lipolytica Levels on the Growth, Feed Utilization, Metabolic Enzymes Activities, Antioxidative Status and Serum Biochemical Parameters of Litopenaeus vannamei
Round 1
Reviewer 1 Report (Previous Reviewer 1)
Change blood for hemolymph in the MS.
The article needs to be revised again in the English language as I detect some grammatical errors.
Did you check the normality and homoscedasticity postulates of the data before performing the paramedical analysis? Include this information in the Statistical Analysis section.
Lines 154-155 “β-Actin was used as the reference gene, and the fold change was 154 calculated with the 2−ΔΔCT method. “ Why is this included?
They indicated in the MOH that they dissected the stomach, but it was not analyzed. What was the purpose of sampling this organ?
Line 279 “Procambarus clarkia[20], “ must say “Procambarus clarkii[20],”
Author Response
Point 1: Change blood for hemolymph in the MS.
Response 1: The question has been modified.
Point 2: The article needs to be revised again in the English language as I detect some grammatical errors.
Response 2: The English language has been checked and modified.
Point 3: Did you check the normality and homoscedasticity postulates of the data before performing the paramedical analysis? Include this information in the Statistical Analysis section.
Response 3: Relevant methods have been supplemented.
Point 4: Lines 154-155 “β-Actin was used as the reference gene, and the fold change was 154 calculated with the 2−ΔΔCT method. “ Why is this included?
Response 4: Sorry, there was an error while writing, it has been deleted.
Point 5: They indicated in the MOH that they dissected the stomach, but it was not analyzed. What was the purpose of sampling this organ?
Response 5: In actual operation, the stomach and intestines were difficult to separate, and the "Stomach" has been deleted.
Point 6: Line 279 “Procambarus clarkia[20], “ must say “Procambarus clarkii[20],”
Response 6: The problem has been modified.
Author Response File: 
Author Response.docx
Reviewer 2 Report (Previous Reviewer 2)
In my opinion, the authors have significantly improved the article. As a last recommendation, the author should be careful when editing the text, for example in line 44 a comma is placed after a space, please correct and check everywhere in the text. References should be formatted according to MDPI.
Author Response
Point : In my opinion, the authors have significantly improved the article. As a last recommendation, the author should be careful when editing the text, for example in line 44 a comma is placed after a space, please correct and check everywhere in the text. References should be formatted according to MDPI.
Response : The full text has been checked and modified.
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
Comments for the author “Effects of diets with varying astaxanthin from Yarrowia lipolytica levels on the growth, feed utilization, metabolic enzymes activities, antioxidative status and serum biochemical parameters of Litopenaeus vannamei”
Abstract
Scientific names in italics, verify the MS. Include mode detail in the treatments that you tested in this section.
Include full names before abbreviations, lines 21 and 23 (TP, ALB, GSH-Px, MDA, T-AOC and I-NOS).
Introduction
This section needs English-language review.
Material and methods
This section must be carefully reviewed.
Lines 97-98 “Each diet was fed to 6 tanks of shrimp for 8 weeks.” If you are testing 7 diets by triplicate and each tank has 50 shrimps, why are you indicating that you are feeding 6 tanks? Please clarify this aspect.
Color is a qualitative variable and cannot be tested using parametric test, you must use nonparametric test. I recommend that authors analyze shrimp color using a numeric color scale with an appropriate statistical test.
How was measured the final concentration of astaxanthin concentration. Please provide the information.
The article shows an incomplete experimental design where seven diets were evaluated, six of which have increased concentrations of T. lipolitica, with control without the yeast, and the seventh diet with 3% H. pluviatilis (2% astaxanthin) is presented. Additionally, external astaxanthin was included (0-120 mg/Kg), which could have a masked effect with Y. lipolítica. What is the basis for using a single dose of H. pluviatilis? In a complete bifactorial experimental design, the same concentrations of H. pluviatilis used with Y. lipolitica would have to be used. Please explain this aspect in detail.
Statistical analysis
Please indicate, which test did you use to verified Normality and homoscedasticity?
Results
Hepatosomatic index, body length, weight gain, feed conversion rate, condition factor and survival are not mentioned in M and M section.
Quadratic regression is not mentioned in statistical analysis at M and M section.
Measured of shell shrimp color is not mentioned with detail in M and M section.
Caspase activity isn’t mentioned in M and M section.
Digestive enzymes are not mentioned in M and M section.
Use “shrimp” and not “prawn” in the MS. Prawn is mainly used for freshwater Palemonids not for marine Penaeids.
Figure 2 showed the astaxanthin content in shrimps. Lines 180-182 “The content of astaxanthin in the mg kg-1 group was the highest. The content of astaxanthin in whole shrimp was positively correlated with that in the diet.” How was corroborated the final astaxanthin concentration in the diets and shrimps?
Shrimp color must be analyzed using color scale and non-parametric statistic.
Table 4 indicate TCH, but in the footnote you use TC, I assume that TCH is Total cholesterol. Please clarify.
Discussion
This section needs a deep English-language review.
This section is straightforward since, in general, comparisons are made with other studies where astaxanthin or yeast supplements are used; however, this study has masked results
Reviewer 2 Report
This study highlighted the fact that the inclusion of Yarrowia lipolytica (astaxanthin content: 1.5%) in the diet of Litopaeneus vannamei has the effect of stimulating growth and improving color quality.
The paper is very well written, the investigation methods are clearly described, the results and discussions are concise.
My specific recommendations are on the one hand the presentation of the work, L42 and L4 the citations [3] [4] and [5] [6] should be [3,4] and [4,5].
L129 where you cite Xu et al, you must also put the year like this ''Xu et al. (2021) [12]''
Attention to the wording of the text, for example L117-120 is a little unclear, please rephrase. The use of the past tense is preferred.
Please check the above mentioned throughout the text.
L 144 should this text be here? ''Effect on Astaxanthin Content of Shrimp''
L175 what represents the Xpot on figure 1, please specify in the text. Also for the method, please specify how you did this calculation, in which program.
L212 in the title of the table you have n=6, this is also found under the table. Please delete the tape and do the same for all the tables.
