Effects of Natural Carotenoid Source Enriched Feed on the Growth, Flesh Carotenoid, Composition, and Palatability of a Silver Barb (Barbonymus gonionotus)

Abstract

Aim: The study compared the effects of different natural carotenoid-enriched feeds with a commercial carp feed on the growth, flesh carotenoid, composition, and palatability of Barbonymus gonionotus. Study Design: The study was conducted with four feeds treated as four treatments where, a commercial carp grower feed was used as control feed (CF) and three test feed were made by adding the powder of three carotenoid sources, viz., tomato (TMP), carrot (CRP), and beetroot (BRP) in the control feed at a rate of 2g/kg. Fifteen juveniles of B. gonionotus were stocked in each cage. The fish were fed with test feed twice a day at the rate of 5% (2.5% + 2.5%) of body weight and weighed fortnightly to adjust the ration size. Place and Duration of Study: The trial was conducted in twelve cages set in a pond at the Department of Fisheries, University of Rajshahi, Bangladesh, for 90 days. Methodology: At the end of the trial, the growth and feed utilization parameters, viz., weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio (PER), flesh carotenoid and composition, and palatability indicators of the fish were evaluated according to standard formulae, spectrophotometry, AOAC, and organoleptic sensory technique, respectively. Results: The higher WG (193.89±12.31 g) and SGR (1.41±0.08 %), better FCR (1.59±0.16) and PER (3.07±0.31), and higher carotenoids content (4.31±0.29 mg/g) were found in the fish fed with carrot-enriched feed, followed by the fish fed with tomato-enriched feed (WG: 174.86±11.50 g, SGR: 1.33±0.01 %, FCR: 1.74±0.04, PER: 2.78±0.06 and Carotenoids: 1.59±0.09 mg/g) and the beetroot-enriched feed (WG: 168.56±12.87 g, SGR: 1.30±0.08 %, FCR: 1.84±0.19, PER: 2.66±0.28 and carotenoids: 1.44±0.40 mg/g) when compared to the control fish. No significant difference in the flesh composition was found among the treatments. A significantly higher organoleptic sensory score (25.54±0.57) was recorded in the fish fed with carrot-enriched feed and lower in the control feed (19.52±0.77). Conclusion: The study concludes that 2g/kg carrot powder supplementation in feed is better for enhancing the growth, carotenoid deposition, and palatability of B. gonionotus.