# Suitable Acidified Eggshell Powder Food Promotes Brachionus calyciflorus Growth and Reproduction: From Antioxidant Capacity Insight

## TL;DR

Adding acidified eggshell powder to rotifer food improves their growth, reproduction, and antioxidant activity, making them better fish larvae bait.

## Contribution

The study identifies 20 mg/L acidified eggshell powder as optimal for rotifer growth and reproduction.

## Key findings

- Population density and antioxidant enzyme activity increased in 20–160 mg/L eggshell powder treatments.
- F2 rotifers in 20–40 mg/L groups had longer generation times and lifespans compared to the control.
- Egg production in F2 rotifers was higher in 20–80 mg/L treatments than in the control group.

## Abstract

Rotifers are natural initial bait for fish larvae in freshwater. Here, the effects of various concentrations of acidified eggshell powder solutions (0, 20, 40, 80, 160, and 320 mg/L) on the growth and reproduction of the rotifer Brachionus calyciflorus were evaluated in culture experiments (11 days). The population density, catalase (CAT) and superoxide dismutase (SOD) activity, and Na and Mg contents in rotifers were significantly higher in the 20–160 mg/L groups than in the control group. A redundancy analysis showed that the Na, Mg, Cr, K, and Ca contents were positively correlated with the rotifer population density and CAT and SOD activity. Furthermore, the generation time and lifespan of F2 rotifers were significantly higher in the 20–40 mg/L treatment groups (82.0 ± 3.7 hr and 162.0 ± 2.7 hr, respectively) than in the control group (64.0 ± 4.0 hr and 128.0 ± 4.0 hr, respectively). Average egg production in F2 rotifers was significantly higher in the 20–80 mg/L treatment groups (15.2 ± 0.7 individuals) than in the control group (11.7 ± 1.2 individuals). These results indicate that 20 mg/L eggshell powder is optimal for growth and reproduction in B. calyciflorus, providing a theoretical basis for using new mineral sources in high-quality open bait for fish larvae.