# Effects of Different Substrates on Growth, Serum Biochemical Parameters, and Behavioral Characteristics of Juvenile Asian Giant Softshell Turtles, Pelochelys cantorii

## TL;DR

This study shows that using fine sand as a substrate improves the growth and behavior of endangered Asian giant softshell turtles in captivity.

## Contribution

The study identifies fine sand as the optimal substrate for rearing juvenile Pelochelys cantorii, enhancing growth and reducing stress.

## Key findings

- Turtles in fine sand and pea gravel groups grew faster and had lower malondialdehyde levels than those with no substrate.
- Fine sand reduced escape attempts and increased resting behavior in juvenile turtles.
- No significant differences were found in most blood chemical indicators across the three groups.

## Abstract

The Asian giant softshell turtle (Pelochelys cantorii) is a highly protected aquatic animal on the brink of extinction, so artificial breeding is crucial for its survival. We aim to find out how different substrates in rearing containers—fine sand, pea gravel, or no substrate at all—affect juvenile turtles’ growth, serum biochemistry (the chemical makeup of their blood), and behavior. We raised 45 juvenile turtles for 18 days, splitting them evenly into three groups with the different bottom materials. Results showed young turtles in the fine sand and pea gravel groups grew faster than those with no substrate, and their blood had less malondialdehyde (MDA). Juveniles in the fine sand group also spent more time resting quietly in a hidden state and tried to escape much less often. No major differences were found in other blood chemical indicators across the three groups. This finding helps people choose the best substrate for raising juvenile P. cantorii, supporting their healthy growth and aiding the conservation of this endangered species.

The critically endangered Asian giant softshell turtle (Pelochelys cantorii) is a national first-class protected aquatic animal in China, and artificial breeding is vital for its conservation. Given the pivotal role of substrate in captive rearing, this study aimed to investigate the effects of different substrate types on the growth, serum biochemistry, and behavior of juvenile P. cantorii. A total of 45 8-month-old juveniles [(121.11 ± 0.65) g] were randomly allocated to three groups (fine sand [FS], pea gravel [PG], and no substrate [NS]) for an 18-day rearing trial. Results indicated that the FS and PG groups exhibited significantly higher weight gain and specific growth rates than the NS group (p < 0.01). Serum malondialdehyde (MDA) levels were lower in the FS and PG groups than in the NS group (p < 0.05), with no significant difference between FS and PG. Notably, three individuals in the NS group exhibited symptoms of skin ulceration. No significant intergroup differences were observed in glucose (GLU), triglyceride (TG), catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), or cortisol (CORT) levels (p > 0.05). Behaviorally, the FS group demonstrated the highest hidden rest frequency and duration (p < 0.01) and significantly lower active avoidance behavior compared to PG and NS (p < 0.01). In conclusion, substrate type significantly influences captive juvenile P. cantorii, with fine sand being optimal as it enhances growth, alleviates oxidative stress, and reduces maladaptive behaviors.