Effects of Hibiscus rosasiensis as a natural carotenoid on growth performance, body composition, pigmentation and carotenoid in blood plasma of blue gourami, Trichogaster trichopterus at different stocking densities

This study examined the effects of the supplementation of China rose powder of Hibiscus rosasiensis towards blue gourami with different stocking densities.China rose (1.5%) was used on two different stocking densities (20 and 30 fishes per aquarium). The group that contain a total of 20 (individual/aquarium) and 30 (individual/aquarium) densities of fishes, are referred as CH1 and CH2 respectivelyand control group of 20 and 30 (individual/aquarium) are referred as CR1 and CR2.Colour parameters (L*Lightness a*Redness b*Yellowness) were measured at the behind of operculum zone weekly. Results indicated that in the most of weeks, there is no significant difference for (L* a* b*) over the 70 days. For carotenoids at density of 20 and 30(individual/aquarium) with the addition of China rose powder, the amount of total carotenoids, canthaxanthin and β-carotene in the skin were significantly different between CH1 to its control CR1, and CH2 to its control CR2. There were also significant differences in canthaxanthin contents in between CH1 and its control CR1; and CH2 and its control CR2 for caudal fin of fishes. In the comparison between group CH1 and CR1, significant differences was observed in the content of canthaxanthin and β-carotene in the blood plasma of fishes while for CH2 and CR2 significance was observed on astaxanthin,canthaxanthin and β-carotene in the blood plasma.The study shows that the China rose powder  are a powerful natural carotenoid source for blue gourami to enrich its colour and also speed up growth  in low density.