Abstract
This study investigates the effects of supplemental carotenoid pigments on growth and color performance in bighead catfish (Clarias macrocephalus). Two experiments were undertaken to determine the appropriate types, feed duration, and dose of astaxanthin (As), canthaxanthin (Ca), and xanthophyll (Xa) pigments individually and in combination. In the first experiment, fish were fed with one control diet (basic diet), six experimental diets comprised of three diets of As, Ca, and Xa at a 100 mg/kg rate of supplementation, respectively, and three diets combinations of As + Ca, As + Xa, and Ca + Xa at a supplement rate of 50 mg + 50 mg/kg. The results showed no significant difference in weight gain (WG), specific growth rate (SGR), survival rate (SR), and feed conversion ratio of fish among treatments (p > 0.05) after 6 weeks. The L* (Lightness) and a* (redness) values in the Xa diet were significantly lower than other treatments, while b* (yellowness) was significantly higher than in the control and others treatments (p < 0.05). These values peaked after 4 weeks and remained stable until the end of the experiment. Consistently, the highest muscle carotenoid content (16.89 ± 0.60 mg/100 g) was found in the fish fed with the Xa diet. The Xa diet was selected for the second experiment. This experiment consisted of four Xa supplemented diets at rates of 25, 50, 75, and 100 mg/kg and a basal diet without any Xa supplementation. The results showed that there was no difference in the SGR or SR of fish fed various Xa levels (p > 0.05). Fish fed the Xa diet of 75 mg/kg were the most preferred by consumers for the natural “yellowness” of muscle. Thus, the results suggested that additional carotenoid pigments did not affect the growth performance of fish. Farmers and feed producers could utilize Xa at an optimal dose of 75 mg/kg to enhance color performance in the market size of bighead catfish for at least 4 weeks prior to harvest.
Highlights
Introduction published maps and institutional affilBighead catfish Clarias macrocephalus is one of the most popular and economically important indigenous fish in Southeast Asia [1,2,3,4,5]
The results show that the highest final weight (Wf ) was found in those fish fed the xanthophyll diet
Statistical analysis by one-way ANOVA showed no significant difference in specific growth rate (SGR)
Summary
Bighead catfish Clarias macrocephalus is one of the most popular and economically important indigenous fish in Southeast Asia [1,2,3,4,5]. The fish has become one of the most important freshwater species for the aquaculture industry in Vietnam [3,4,5]. The market values of this fish depend on meat quality and taste and rely on skin and muscle pigmentation performance. Buyers and consumers alike prefer good quality bighead catfish to have yellowish skin and muscle tone. This is the most important characteristic of fish quality at the market. Other studies reported that the color of the fish is the first characteristic perceived and is a determinant selection criterion, directly related to subsequent acceptance or rejection [6,7]
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