Automated Feeding and Restricted Diet Can Lead to Longer Lifespans in Male African Killifish

Yukta Kulkarni ’22

Figure 1: Male African Killifish have longer lifespans with restricted diets.

When performing biological research regarding health and disease, it is often not possible to have humans as primary test subjects. Thus, other animals are used for research purposes as they model human developments, have a smaller lifespan, and allow for more efficient research. For example, the African turquoise killifish is a type of fish used for research since it has a lifespan of 4-6 months. Furthermore, it is used as an indicator of aging, fertility decline, wound healing, heart function, and cancer risks all to model diseases in humans. Since it has a multitude of applications, researchers wanted to determine the proper diet for African turquoise killifish to maintain pristine health, growth, and fertility. The fish have to be fed the same amount of food consistently, or they are likely to not eat, which can cause slight differences in the results of any experiment performed. To combat this, the researchers built an automated feeding system to help determine the optimal amount of feedings and when during the day they should be fed for fish health and longevity.

Researchers at Stanford University, led by Andrew McKay, designed an experiment where they would feed two groups of African turquoise killifish different diets using their automated feeding system. One group would receive an ad libitum diet which consisted of 7 feedings of a total of 5mg per day over 12 hours. The other group would receive diet and time-restricted feeding conditions, consisting of 3 feedings of a total of 5 mg per day over 2 hours. This was done over the fishes’ entire lifespan. The different diets did not have a significant effect on female fish. However, it was noticed that only the male fish who were fed the restricted diet would have a longer lifespan than the male fish fed ad libitum. In fact, the male fish fed the restricted diet lived longer than the female fish in the same group. 

This finding is essential for the researchers to understand as they do not want to unnecessarily shorten the fishes’ lifespan. The automated feeding system will ensure that the fish are being fed at the correct intervals, the appropriate amount of food, and during the set hours to sustain their health. This can tremendously help researchers as they can focus their time on analyzing results rather than the upkeep of the fish. However, only two types of diets were tested in this experiment, leading to inconclusive results as another diet not tested can be optimal for both the male and female African turquoise killifish. 

References:

[1] A. McKay, et al., An automated feeding system for the African killifish reveals effects of dietary restriction on lifespan and allows scalable assessment of associative learning. bioRxiv (In review). doi: https://doi.org/10.1101/2021.03.30.437790 

[2] Image retrieved from: https://commons.wikimedia.org/wiki/File:Fundulopanchax_sjostedti_%27Red_dwarf%27.jpg 

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