Growth Performance, Digestive Efficiency, and Meat Quality of Two Commercial Crossbred Rabbits Fed Diets Differing in Energy and Protein Levels

Round 1

Reviewer 1 Report

L125: The post weaning diets were administered from 33 to 64 d of age. The increase of DE … - The dot before The is missing

L296-297: „The rabbits fed LE diets also showed a worse FCR compared to those fed LE diets from 37 to 64 days of age (+0.51 units; p < 0.001), …” You compared LE with LE. Correctly: The rabbits fed LE diets also showed a worse FCR compared to those fed HE diets from 37 to 64 days of age (+0.51 units; p < 0.001), …

L399-402: This effect (farm) was not considered in the evaluation. It would have been more fortunate to start the experiment with the same weaning weight or raise the kits under the same conditions. Thus, the weaning weights were not only influenced by the maternal effect …

L428: „ … the relative growth of body tissues [50].” - The parenthesis before 50 is missing

Author Response

REVIEWER 1

L125: The post weaning diets were administered from 33 to 64 d of age. The increase of DE … - The dot before The is missing.

Authors

The dot has been inserted (now L127).

 Reviewer 1

L296-297: „The rabbits fed LE diets also showed a worse FCR compared to those fed LE diets from 37 to 64 days of age (+0.51 units; p < 0.001), …” You compared LE with LE. Correctly: The rabbits fed LE diets also showed a worse FCR compared to those fed HE diets from 37 to 64 days of age (+0.51 units; p < 0.001), …

Authors

The sentence has been corrected (now L297-298).

Reviewer 1

L399-402: This effect (farm) was not considered in the evaluation. It would have been more fortunate to start the experiment with the same weaning weight or raise the kits under the same conditions. Thus, the weaning weights were not only influenced by the maternal effect …

Authors

Thank you, we agree with your comment, but unfortunately it is not possible to find commercial farms that raise both genetic strains in the same environmental and management condition. We were able to synchronize reproductive activity in the two farms and obtain weaned rabbits of the same age to be simultaneously transferred to the experimental station. For this, we have covaried the data on the initial weight of the two strains. The sentence has been slightly modified this way “However, Grimaud and Hyla rabbits came from two different commercial farms and many factors, including management, diets provided to lactating does, environmental and hygienic conditions of the farms could have affected the weaning weight of the animals” to underline that the weaning weight was not only influenced by the maternal effect (now L400-403).

Reviewer 1

L428: „ … the relative growth of body tissues [50].” - The parenthesis before 50 is missing

Authors

The parenthesis has been added (now L429).

Reviewer 2 Report

This manuscript highlights a interesting question on the possibility of reducing energy and protein content on commercial rabbit feed. The methods seem well applied. I am only concerned on some of the conclusions the authors draw since the statistics do not point in that direction. Apart from that it is an interesting work and I think it is suitable for publication after it is revised and these details are corrected. 

L. 35 - "LP – 144 g/kg". Is this value correct? Shouldn't it be 142 or 146? Or are the authors presenting the mean of these two values?

L. 116 - Although the animals were randomly allocated was the number of females to males in each group constant or did it vary? Was sex taken into consideration in the results?

L. 474 - "raw"

L. 522 - I don't think the authors can conclude either breed  showed better or worse results since the statiscs do not point this out.

L. 396 - Although the authors state there were differences between genotypes on live weight at weaning, according to the results no significant differences were found. I understand that there is a numerical difference but don't think this should be so discussed since it could cause confusion on the readers. Please clarify on the text that there are no significant differences. I wouldn't keep this part of the discussion.

Author Response

REVIEWER 2

Reviewer #2: This manuscript highlights an interesting question on the possibility of reducing energy and protein content on commercial rabbit feed. The methods seem well applied. I am only concerned on some of the conclusions the authors draw since the statistics do not point in that direction. Apart from that it is an interesting work and I think it is suitable for publication after it is revised and these details are corrected.

Authors

Thank you for your comments.

Reviewer 2

L35 - "LP – 144 g/kg". Is this value correct? Shouldn't it be 142 or 146? Or are the authors presenting the mean of these two values?

Authors

The value is correct; we are presenting the mean of the two low protein diets. The sentence has been modified as “two DE levels (high, HE – 10.9 MJ/kg vs. low, LE – 9.2 MJ/kg, on average) and two CP levels (high, HP – 159 g/kg vs. low, LP – 144 g/kg, on average)” (now L34-35).

Reviewer 2

L116 - Although the animals were randomly allocated was the number of females to males in each group constant or did it vary? Was sex taken into consideration in the results?

Authors

Each experimental group was composed by half females and half males, so the sex was not considered in the results. The sentence has been modified to clarify the point “…randomly allocated to eight experimental groups (48 animals per group; half females and half males), …” (now L118).

Reviewer 2

L474 - "raw"

Authors

The word has been corrected (now L475).

Reviewer 2

L522 - I don't think the authors can conclude either breed showed better or worse results since the statics do not point this out.

Authors

Thank you for the comment. The sentence has been modified as “In the condition of the present trial, Grimaud and Hyla rabbits achieved similar growth performance and final live weight, but the formers showed higher carcass yield and feed to carcass conversion ratio.” (now L523-525). The significant difference between genotypes on carcass yield is reported in Table 6 and described in the result section (now L358-360), while the significant effect of the genotype on the feed to carcass conversion ratio is described at now L364-365).

Reviewer 2

L396 - Although the authors state there were differences between genotypes on live weight at weaning, according to the results no significant differences were found. I understand that there is a numerical difference but don't think this should be so discussed since it could cause confusion on the readers. Please clarify on the text that there are no significant differences. I wouldn't keep this part of the discussion.

Authors

Thank you for the comment. However, the difference between genotypes on live weight at weaning was significant (P<0.01) (please, see Table 2 and now L284-287), thus it was used as covariate for the analysis of growth performance and carcass traits. In our opinion this point deserves a comment in the discussion section.