The Effect of Hot Water Extract of Tilapia on Exercise Capacity in Mice

Round 1

Reviewer 1 Report

The authors studied the effect of hot water extract of tilapia (HWET) (Oreochromis mossambicus) in mice in a swimming endurance test. The administration of HWET unambigously enhanced the exercise capacity of the mice in a dose-dependent manner, increasing the swimming time. After the test, the blood samples were collected and serum biochemical parameters were measured.

The mansucript is suitable for publication after minor revision.

Line 97.: A reference on the protocol (NPUST-105-024) of animal experiments is missing.

Lines 238-240, Figure 2: The HWET treatment decreased the serum levels of lactate and creatine kinase in a dose-dependent manner, but not in case of alanine aminotransferase (ALT). This observation needs explanation or further study.

The conclusions are not detailed enough, they can be improved, e.g. the most important observations on the swimming endurance test are missing.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

The article is interesting and novel, but without a proper description of the fish concentrate HWET is impossible to figure what are the biochemical effects that lead to the physiological benefits claimed.

It is critical to propose a hypothesis or postulate a model for the compounds that let to the benefits, not just describe them. for that is crucial to know the composition of the HWET.

Main concerns:

There is no detailed description of the preparation of the hot water tilapia extract (HWET). Is it a lyophilized fish broth? 

A proximal composition is a minimal requirement to describe the HWET, besides the amino acid profile included in table 1.

Also, the diet (oral gavage?) of the mice is not described, is it isocaloric and isoproteic after inclusion of the HWET? Was it fed ad libitum? There were records of the food consumed? Did the HWET change the average consumption of feed?

Is HWET is a sub-product of the tilapia industry? What would be the benefit of HWET vs. eating the tilapia muscle? Why would anyone would use HWET instead?

For the Western blot, show in supplementary materials an image of the whole membrane to see that there are no background signals in other bands and the proper controls.

References to check:

An adjustable-current swimming pool for the evaluation of endurance capacity of mice    Matsumoto, K., Ishihara, K., Tanaka, K., Inoue, K., Fushiki, T.    1996    Journal of Applied Physiology
81(4), pp. 1843-1849

Chen, Y.-J.; Kuo, C.-Y.; Kong, Z.-L.; Lai, C.-Y.; Chen, G.-W.; Yang, A.-J.; Lin, L.-H.; Wang, M.-F. Anti-Fatigue Effect of a Dietary Supplement from the Fermented By-Products of Taiwan Tilapia Aquatic Waste and Monostroma nitidum Oligosaccharide Complex. Nutrients 2021, 13, 1688. https://doi.org/10.3390/nu13051688

Structural characterization, erythrocyte protection, and antifatigue effect of antioxidant collagen peptides from tilapia (: Oreochromis nilotica L.) skin    Ren, Y., Wu, H., Chi, Y., Deng, R., He, Q.    2020    Food and Function
11(11), pp. 10149-10160
3

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Thanks for the corrections made and the questions addressed.