Dietary astaxanthin improved the body pigmentation and antioxidant function, but not the growth of discus fish (Symphysodonspp.)

Abstract

To assess the effects of dietary astaxanthin on the growth and body colour of red discus fish (Symphysodon spp.), synthetic astaxanthin was added into the basal diet (beef heart hamburger) with the levels of 0 (control diet), 50, 100, 200, 300 and 400 mg kg À1 respectively. The six experimental diets were fed to discus fish with an initial body weight of 10.3 AE 0.8 g for 8 weeks. The results showed that the supplementation of 50-200 mg kg À1 astaxanthin had no significant effects on growth performance of discus fish, but the high supplementation of astaxanthin (300 or 400 mg kg À1 ) significantly reduced the weight gain and increased the feed coefficient ratio (P < 0.05). After 4 or 8 weeks of feeding, the L* (lightness) values in astaxanthin-supplemented groups were significantly lower, while a* (redness), b* (yellowness) and skin astaxanthin contents were significantly higher than the control group (P < 0.05). When the astaxanthin supplementation reached 200 mg kg À1 , skin redness and astaxanthin contents remained relatively stable. When b* was relatively stable, the supplemental astaxanthin was 300 (4 weeks) and 50 mg kg À1 (8 weeks) respectively. With the supplemental astaxanthin increasing, the astaxanthin retention rate significantly decreased and hepatic total antioxidant capacity was strengthened. The dietary astaxanthin also significantly increased the reduced glutathione level (P < 0.05) when the astaxanthin inclusion was higher than 50 mg kg À1 . The above results showed that dietary astaxanthin could effectively improve the skin pigmentation of red discus fish in 4 weeks and the supplementation level was suggested to be 200 mg kg À1 .

Effects of dietary vitamin C and vitamin E on the growth, antioxidant defence and digestive enzyme activities of juvenile discus fish (Symphysodon haraldi)

“…The animals were then acclimated at a temperature of 30°C in a flow system for a period of 14 days prior to the start of the feeding trial. During the acclimation, the animals were fed daily with D0 diet at a ratio of 40 g/kg of their mean wet mass (Song et al., ). After 2 weeks of acclimation period, a total of 390 animals with similar size (initial body weight: 7.96 ± 0.61 g and body length: 5.45 ± 0.65 cm) were randomly distributed in 39 circular and temperature‐controlled glass tanks (75 L).…”

“…With the blooming of S . haraldi industry in the world, there are increasing research efforts on their nutritional requirements such as feed ingredients (Wen, Chen, Qu, & Gao, ), protein requirements (Chong, Hashim, & Ali, ) and demand of pigments (Song et al., ). However, studies on the micronutrient requirements of S .…”

Dietary dl-methionyl-dl-methionine supplementation increased growth performance, antioxidant ability, the content of essential amino acids and improved the diversity of intestinal microbiota in Nile tilapia (Oreochromis niloticus)

“…Catalase (CAT) activity was determined by determining the initial amount of hydrogen peroxide decomposition at 240 nm (25) . Antioxidants could reduce Fe 3þ to Fe 2þ , the later could form solid clathrate with phenanthroline, and then the total antioxidant capacity (T-AOC) was measured according to the absorption value at 520 nm (26) . The activities of SOD and CAT, T-AOC and the content of MDA were determined by using commercial kits (Nanjing Jiancheng Bioengineering Institute) following the manufacturer's protocol.…”

Maximization of Astaxanthin Production from Green Microalga &lt;i&gt;Haematococcus pluvialis&lt;/i&gt; Using Internally-Illuminated Photobioreactor

“…It is also applied to feed supplements for salmon and rainbow trout as a food coloring agent [14,15]. The astaxanthin pigment imparted in the fish Using Internally-Illuminated Photobioreactor bodies can enhance their immunity and reproduction capacity [8,[16][17][18].…”