The Effects of Olive Cake Supplementation on Feedlot Performance and Longissimus Muscle Fatty Acid Composition of American Wagyu Steers and In Vitro Rumen Fermentation Characteristics

Round 1

Reviewer 1 Report (Previous Reviewer 1)

Authors addressed all comments arisen by the reviewers, I believe the manuscript could be accepted in the current form 

Reviewer 2 Report (Previous Reviewer 2)

thank you for your edits and comments.

Reviewer 3 Report (Previous Reviewer 3)

No extra comments

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

The idea of using olive meal as alternative feed is interesting and applicable at the commercial level. There are minor issues that should be addressed before accepting this manuscript. 

Line 9: please define olive meal? is it olive cake?

Line 11 and 66: the number of animals is different between what is mentioned in the abstract and in the materials and methods, please clarify 

Line 12: please define BW first time it appears

Line 23: please define or use full name because it used only one time in the abstract

Line 67: in the manuscript, authors discussed the effect of live meal on longissimus muscle and nothing is mentioned about the carcass characteristics, please change or clarify 

Lines 85-90: in the footnote of Table 1, please provide a reference for all use equations

line 120: why the diet in experiment 2 is differed from the ones used in experiment 1?

Lines 178-179: according to results in Table 2, feed efficiency did not differed, please fix this issue 

 

 

Author Response

Thank you for your time, please see the attachment

Author Response File: Author Response.docx

Reviewer 2 Report

Review of Manuscript: Tangredi et al . “ Effects of Olive Meal … Fermentation Characteristics”

 

General:

The manuscript is of potential interest and is well written.  The experimental design and methods seem to be appropriate.

I am curious about how much olive meal is available in the US, other countries?  Is it enough to be worthy of feeding?  Is there a guaranteed supply?

 

 

Specific Comments:

Line 9                    I feel the abstract needs an opening statement as to the purpose? What is the problem you are trying to solve?  What is the hypothesis?

 Table 1                 the NE values were calculated from TDN – what is the source of the TDN values?  Source of the equations?  -  assume these are just modified NASEM (2016) equations (i.e. the 0.361 is essentially 4.4 x 0.82).   These were not really typical “finishing” diets, more like growing diets.  Why?

82                           why 5%?

125                        describe the “fermentation “ tubes.  Were they just 50 mL centrifuge tubes or something else?

Table 2                  performance was very poor – is this typical for Wagyu cattle?   Show feed efficiency (actually gain efficiency ) to 3 decimals.

202                        what about the composition of fat from other muscles, locations?

228-230               just a thought (possibly a crazy one) – did olive meal have any effect on the odor from the manure? Or on enteric methane production?  Some phenolics can affect methanogenesis, and production of some odorous volatile organic compounds (if I remember correctly).

255                        complete sentence --- “… Wagyu beef cattle is needed.”  

Author Response

Thank you for your time, please see the attachment

Author Response File: Author Response.docx

Reviewer 3 Report

The manuscript "The Effects of Olive Meal Supplementation on Feedlot Performance and Longissimus Muscle Fatty Acid Composition of American Wagyu Steers and In Vitro Rumen Fermentation Characteristics" sounds interesting and relevant, but there are some limitations on the design of the experiment that make the data reported not valuable.

The manuscript evaluates a by-product that seems to be reach in oleic acid, however the author present that the product has less than 2% of EE. Here is the first limitation, how much or that EE are fatty acids? The authors replace hay for olive meal. and seems that the diets are iso-N and energy, however how is that possible if the olive meal diet has more EE, and the same amount of CP and fiber?  The animals were fed ad-libitum that is not the best way to feed finishing cattle, if the animals have the diet composition as described in the manuscript the fiber length of hay and olive meal probably is the greatest difference, shorter fiber length can cause gut health under this conditions. 

The animals were fed from 700 to 800 (only) 100 kg on already mature animals, the final BW reported in results is different than the one in the materials and methods. Is that a realistic finishing target weight? The statistics mention QG and YG, and no results are on them. The experimental unit is not being defined in the statistical model.

Lines 33-35 are biased based on the QG of each animal. Maximal potential of marbling in Bos taurus is more than 5%

Line 38. Another bias, later research shows that the increase of marbling affects 18:1 concentration not the breed (Jaborek et al 2023).

Line 39 is not the FA what gives the flavor to Wagyu cattle.

Line 48-49, this seems to be a key concept of the experiment, but there is no reference of this statemen.

Line 57. There is nothing in the introduction that will state why olive meal will improve growth.

Not sure if I agree that an in-vitro study is enough to show decrease in BH in olive meal. Biohydrogenation depends on rumen pH and amount of FA entering to the rumen. For the wagyu cattle intake is lesser that other Boss-taurus breeds, so if the intake is low, would it not give time to the rumen bacteria to BH the C18:1?

Olive meal contains 1.3% of ether extract, how much of that is FA? Present the nutrient composition as a % of FA in the diet not as EE

Line 77-78 how it is possible to separate the 8 heaviest animals in 3 and 4?

Line 91. Please describe what was target body weight gain for the diet.

Olive meal replaced hay, however the feeding regimen was not ideal to decrease gut health (Galyean M. L., Malcolm-Callis K. J., Garcia D. R., and Pulsipher D. G.. 1992. Effects of varying the pattern of feed consumption on the performance by program-fed beef steers. Clayton, NM: Clayton Livestock Res. Center, New Mexico State Univ. Progress Rep. No. 78

Line 130 why only DM disappearance and not all nutrients?

The statistical analysis is not clear. Was the data entered as an average of the pen (BW and ADG)? If individual data was entered a random effect of block and pen within block has to be stated to set the pen as the experimental unit, if not pen was the experimental unit. The authors consider covariates and had to be there as part of the design, cannot be removed if not significant or if the AIC is smaller, the AIC is used on the case of covariate structures of the repeated model, not to see what is the best model. Why did the authors used PDIFF, if the authors have 2 treatments the P value of the type 3 effect is the one that corresponds to the treatment difference.

Author Response

Thank you for your time, please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

The authors should not be reporting EE in the diet, that is biased. The authors need to report fatty acid (total and the profile of the entire diet and all the fatty acids). 

Lipids decrease fiber digestibility not total diet digestibility, the authors need to include the NDF and ADF digestibility on the analysis not just total DM

Author Response

• The authors should not be reporting EE in the diet, that is biased. The authors need to report fatty acid (total and the profile of the entire diet and all the fatty acids). 

  • Suggested change was made.
• Lipids decrease fiber digestibility not total diet digestibility, the authors need to include the NDF and ADF digestibility on the analysis not just total DM
  • We did not measure NDF or ADF in the residue of the in vitro experiment