Polyculture of mullets in brackishwater using compounded feed: proximate and mineral profiles in comparision with wild mullets

Abstract

Two stage rearing (nursery and grow-out) of two mullet species, Mugil cephalus and Liza parsia was demonstrated in afarmer’s pond. In the nursery phase, wild collected grey mullet (1.65±0.2 g) and gold spot mullet (1.03±0.1 g) fry numbering450 and 4000, respectively were stocked in pen enclosures. After 30 days of nursery rearing, they were released intothe same pond and reared for 7 months using dry pelleted feed produced in the feed mill of ICAR-Central Institute ofBrackishwater Aquaculture (ICAR-CIBA), Chennai. Feed was formulated using locally available ingredients to contain33.4% crude protein and 5.7% ether extract. The fishes were fed with crumbles (0.8 mm) and pellets (2 and 3 mm) in thenursery and grow-out phases, respectively. The production of both the mullet species together at harvest was 1262 kg ha-1(L. parsia 851 and M. cephalus, 411 kg ha-1). The nutrient composition of the two farmed sympatric mullet species whencompared with their respective wild samples showed a significant variation. Higher lipid content in the farmed fishes wasobserved compared to their respective wild originates. The effect of size was highly significant in lipid content, its valueincreasing proportionately with size (p<0.05) in both wild and cultured fishes. Cultured M. cephalus contained significantly(p<0.05) higher levels of Ca, K, Mn, Cu and Zn, while wild M. cephalus had significantly (p<0.05) higher concentrations ofNa and Fe. The wild collected L. parsia had significantly (p<0.05) higher mineral content compared to the cultured fishes.The dietary value (DV%) of mullets indicates that consumption of 100 g fish could meet the daily requirements of Ca and Pfor adult human being. Mullet could provide 60-75% of dietary value for Se, which is an important micronutrient that playsa major role in scavenging the free radicals due to its anti-oxidative properties. The results of this study demonstrated thetechno-economic viability of mullet culture in farmer’s pond. Mullets are an ideal choice for diversification of brackishwateraquaculture and could serve as an alternative livelihood source and nutritional security for the coastal population.