# Effects of Different Sources and Dietary Inclusion Levels of Astaxanthin on Growth Performance, Skin Pigmentation, and Physiological Parameters of Red Sea Bream (Pagrus major) Juveniles

## TL;DR

This study shows that algal-extracted astaxanthin improves skin color in red sea bream more effectively than synthetic or yeast sources, even at lower doses.

## Contribution

The study identifies algal-extracted astaxanthin as a more efficient and cost-effective source for improving skin pigmentation in red sea bream.

## Key findings

- Algal-extracted astaxanthin at 60 mg/kg improved skin color as effectively as higher doses of synthetic astaxanthin.
- Lower cortisol levels were observed in fish fed algal astaxanthin, indicating reduced stress.
- Growth performance and blood parameters were unaffected by astaxanthin supplementation.

## Abstract

The external coloration of red seabream plays an important role in consumers’ acceptance and market appeal. Three different sources of astaxanthin, i.e., artificially synthesized, algal-extracted, and yeast-extracted astaxanthin, were included in red seabream feeds. Astaxanthin from Haematococcus pluvialis algae led to optimum skin color compared to the artificially synthesized and yeast-extracted astaxanthin. Within 60 days of feeding, the use of 60 mg kg−1 of algal astaxanthin had similar results in coloration as higher levels of artificial astaxanthin, up to 100 mg kg−1. This result was also accompanied by lower cortisol levels in blood.

Red seabream (Pagrus major) reared under intensive rearing conditions faces hypermelanosis and dyspigmentation, resulting in darker and less pink/red skin color, losing the natural appearance of the species. This has a great negative impact on consumers’ acceptance and market appeal. Two experiments were performed to test the effect of the source, level, and feeding duration of astaxanthin supplementation in the feed on red seabream skin color reversing the depigmentation problem. Firstly, three different sources of astaxanthin (artificially synthesized, algal-extracted, and yeast-extracted astaxanthin) at the same inclusion level (100 mg kg−1 feed) were tested. Then, the best performing source was tested using five inclusion levels (0, 20, 60, 80, and 100 mg kg−1) in the feed for 60 days. At the same time, growth performance, blood biochemical parameters, antioxidant capacity and cortisol levels were also assessed. The results showed that red seabream appearance can be significantly improved with the inclusion of astaxanthin from the algae Haematococcus pluvialis in the feed even at lower levels compared to the artificially synthesized astaxanthin for a 60-day period. Fish growth performance and blood parameters were not affected by any of the experimental treatments.