Red tank aquaculture improves reddish body color, flesh quality and taste of pacific white shrimp (Litopenaeus vannamei)

The reddish body coloration of Pacific white shrimp (<i>Litopenaeus vannamei</i>) is a critical quality attribute that significantly influences consumer preference and market value. Intensive aquaculture practices frequently result in impaired pigmentation, and dietary astaxanthin supplementation, while effective, increases production costs. Considering the intrinsic ability of decapod crustaceans to alter their body color in response to environmental backgrounds, we hypothesized that rearing L. <i>vannamei</i> in red tanks would enhance redness, stimulate astaxanthin distribution, improve muscle texture, and enhance flavor without compromising growth performance. Following a 75-day culture period, shrimp reared in red tanks exhibited a significantly higher redness (a* value) in both raw and cooked forms (<i>P <</i> 0.05), alongside enhanced textural parameters including hardness, gumminess, and chewiness (<i>P <</i> 0.05). Furthermore, increased levels of umami-related amino acids were detected in the muscle of shrimp reared in red tanks (increased by 15.3 %, <i>P <</i> 0.05). Astaxanthin content was elevated in the shell (increased by 25.8 %, <i>P <</i> 0.05) but reduced in the hepatopancreas (decreased by 18.5 %, <i>P <</i> 0.05), indicating a facilitated redistribution of the pigment. This redistribution was corroborated by the upregulation of the red pigment-concentrating hormone (<i>rpch</i>) gene in the hepatopancreas (<i>P <</i> 0.05). Although survival rate was marginally lower (decreased by 7.0 %, <i>P <</i> 0.05), growth remained unaffected. These findings collectively indicate that red tank culture offers an economically viable and feed-free strategy to enhance the visual appeal and sensory quality of L. <i>vannamei</i>, presenting a promising alternative to dietary pigment supplementation.