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Fish meal replacement with squilla (Oratosquilla nepa, Latreille) silage in a practical diet for the juvenile giant freshwater prawn, Macrobrachium rosenbergii de man, 1879

Bijoy, Valiyaparambil Mohanan, Sabu, Sarasan, Harikrishnan, Mahadevan
Aquaculture international 2018 v.26 no.5 pp. 1229-1245
Macrobrachium rosenbergii, Squilla, ash content, average daily gain, carcass composition, crude protein, experimental diets, feed conversion, fish meal, juveniles, lipids, postlarvae, shrimp, silage, specific growth rate, survival rate, water uptake, weight gain
Replacement of fish meal with squilla silage in practical diet for the juvenile giant freshwater prawn, Macrobrachium rosenbergii, was evaluated. Five iso-nitrogenous and iso-caloric diets were prepared in which protein requirements were met with 100% fish meal (control, diet 1) and squilla silage replacing fish meal at 25, 50, 75 and 100% (diets 2, 3, 4 and 5, respectively). Water stability and water absorption of five feeds revealed significant differences (P < 0.05). The weight gain varied between a maximum of 248.50 ± 34.07% in diet 4 to lowest 132.45 ± 14.34% in diet 1. The average daily gain in weight in grams varied from 0.091 ± 0.01 (diet 5) to 0.154 ± 0.04 (diet 3), whilst the specific growth rate and gross growth coefficient values were recorded highest in diet 4. Highest survival rates (86.66 ± 5.77%) were recorded in both experimental diets 4 and 5. Low feed conversion ratio of 1.19 ± 0.21 was recorded from diet 4, whilst the highest value of 2.16 ± 0.09% was estimated from the diet 5. Proximate carcass composition showed highest crude protein content in post-larvae fed with diet 5 (47.24%) in contrast to lowest diet 1 (36.12%). Lipid values fluctuated significantly between 2.45 and 7.18% (P < 0.05) between treatments. The ash content significantly increased from diet 1 (16.34%) to diet 5 (20.69%) (P < 0.05). Highest feed efficiency (gain/feed) value was recorded in diet 4 (1.52 ± 0.22), whilst the diet 5 showed lowest value (0.99 ± 0.06). The results suggested that squilla silage can be utilised up to 75% of the protein in prawn diets for fish meal replacement.