# Effects of Tagetes erecta on the Pigmentation of Large Yellow Croaker(Larimichthys crocea)

## TL;DR

This study shows that adding Tagetes erecta to the diet of large yellow croaker improves their body color more effectively than other supplements, boosting their commercial value.

## Contribution

The study demonstrates that Tagetes erecta extract enhances body color in L. crocea more effectively than astaxanthin or amaranth extract.

## Key findings

- T. erecta increased the a∗ value (red–green) 1.25-fold compared to the control group.
- The ventral b∗ value (yellow–blue) was significantly elevated (p = 0.028) in the T. erecta group.
- T. erecta improves color by regulating carotenoid uptake and melanogenesis.

## Abstract

Larimichthys crocea (L. crocea), an important species in mariculture, is highly valued for its nutritional benefits, delicate flavor, and distinctive golden body, making it a popular choice among consumers. However, suboptimal breeding conditions and high stocking densities, often lead to reduced flesh texture and a deterioration in body color. Given the significant role body color plays in determining the commercial value of this species, this study evaluated the impact of various dietary supplements on color enhancement. One basal diet and three separate experimental diets were formulated: one supplemented with 200 mg/kg Tagetes erecta extract (2% lutein), one with 200 mg/kg astaxanthin (2%), and one with 200 mg/kg amaranth (Amaranthus spp.) leaf extract (85%). The results indicated that T. erecta was more effective in enhancing the body color of L. crocea than the other two supplements after 28 days of feeding, with the a∗ value (red–green) 1.25-fold higher than the control group and ventral b∗ value (yellow–blue) was significantly elevated (p = 0.028) compared to the control group. Initial mechanistic studies revealed that T. erecta enhanced body color through regulating carotenoid uptake and melanogenesis. These findings provide valuable insights for optimizing feeding strategies to improve the market appeal and commercial value of L. crocea in mariculture.