Evaluation of organoleptic qualities of fish grown in ponds treated with different organic manures

Catla, rohu, silver carp and common carp raised employing different organic manures were subjected to organoleptic evaluation, both in raw and cooked form. The combination treatment of poultry manure and silkworm faecal matter had positive effect on colour and glossiness of skin and colour of flesh in the case of common carp. Though no significant difference was observed in the overall quality, odour of flesh and texture of meat of rohu were found to be better in sewage treated and poultry manure treated ponds respectively. From the results, it can be discerned that treated sewage has no adverse effect on the acceptable qualities of the carps studied

Effect of microbial biofilm in the nursery phase of mrigal, Cirrhinus mrigala

The experiment was conducted for 35 days in nine cement tubs (1 x 1 x 1 m) having 15 cm sandy-loam soil base with three treatments in triplicate, viz., cow dung alone at the rate of 1 kg/tub (T sub(1)), cow dung at 1 kg/tub and feed at 10% body wt/d in two meals (T sub(2)), and cow dung at 1 kg and paddy straw at 200 g/tub (T sub(3)). Both manure and substrate were added on dry weight basis. All the tubs were stocked with 10 fry each mrigal (100,000/ha) of average weight of 0.09 g, seven days after the addition of manure and substrate. The total plate count of bacteria in water did not vary much between the treatments and the mean values were 5.13, 5.49 and 5.85 (CFU x 10 super(4)/ml) in T sub(1) T sub(2) and T sub(3) respectively. The number of phytoplankters and zooplankters in water differed significantly between the treatments. The average number of attached algae (no./cm³) and fish food organisms (no./cm³) recorded on the substrate were 145.28 and 70.67, respectively. The mean final weight of mrigal differed significantly (P < 0.05) between the treatments with T sub(3) registering the highest value of 6.93 g followed by T sub(2) (5.01 g) and T sub(1) (3.37 g). The specific growth rate and growth increment of fish also followed the same trend as that of weight recorded in the different treatments. Survival was higher in T sub(2) (83.33%), followed by T sub(3) (80.00%) and T sub(1) (76.67%). The study demonstrates that by the introduction of biodegradable substrates like paddy straw into the culture systems, significantly higher growth and survival can be obtained in the nursery rearing of mrigal

Periphyton-based jaraqui (Semaprochilodus Insignis) culture with two types of substrates at different densities

Influences of two types of substrates, natural (macrophyte, Pistia stratiotes) and artificial (plastic screen) were evaluated at 3 differrent densities (10, 20, 30%) on periphyton development, water quality and growth performance of jaraqui (Semaprochilodus insignis). Fish of average initial weight 1.46-1.69 g and length 4.15-4.26 cm stocked at 1/m2 in 46 m2 masonry tanks were grown for 120 days. The tanks were fertilized with urea, triple superphosphate and wheat bran. The types and densities of substrates tested did not drastically influence water quality. Natural substrate harboured higher periphyton biomass (1.48±0.09 mg/cm2) as well as species diversity (28 genera) than the artificial substrate (0.84±0.12 mg/cm2, 20 genera,). Fish in 10% and 20% artificial substrate and 20% natural substrate treatments showed better mean values of body weight (24.64, 23.86, 29.26 g respectively) on termination of the experiment. Fish survival was the lowest in 30% natural substrate (84.1%) and highest in 10% artificial substrate (94.2%). Higher fish biomass was recorded in 20% natural and 10% artificial substrate treatments (25.05 and 21.71 g/m2), which amounts to a four-month yield of 250 and 217 kg/ha in the two treatments. © Published by Central Fisheries Research Institute (CFRI) Trabzon, Turkey

Evaluation of indigenous marine periphytic Amphora, Navicula and Cymbella grown on substrate as feed supplement in Penaeus monodon postlarval hatchery system

Three isolated marine diatoms (Amphora, Navicula and Cymbella) grown on substrate were evaluated as feed supplement for Penaeus monodon postlarvae (PL) in hatchery system for a period of 19 days without changing water. Specific growth rate (day)1) (0.27 ± 0.0) and survival (%) (56.3 ± 1.8) of PLs were significantly higher (P < 0.05) in treatment tanks when compared with the control (0.20 ± 0.0; 36.0 ± 1.5, respectively). Shrimp PLs reared in substrate-based tanks had significantly higher (P < 0.05) levels of protein, lipid (521.0 ± 7.0; 304.0 ± 2 g kg)1 dry weight, respectively), ecosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)(189.0 ± 2.0; 176.0 ± 2 g kg)1 of total fatty acid, respectively) than the control (435.0 ± 22.0; 258.0 ± 22 g kg)1 dry weight; 172.0 ± 5.0; 152 ± 2 g kg)1 total fatty acid, respectively). The periphytic diatoms contained protein and lipid (430–490; 230–260 g kg)1 dry weight, respectively), EPA (30–150 g kg)1 of total fatty acids), DHA (20–30 g kg)1 of total fatty acids) and nine essential amino acids. The results showed that isolated marine periphytic diatoms grown on substrate could be used as feed supplement in enhancing the growth and survival of P. monodon postlarvae

Growth performance of common carp, Cyprinus carpio fed varying lipid levels through low protein diet, with a note on carcass composition and digestive enzyme activity

Protein sparing by lipid has been demonstrated in certain cultivable species of fish. This study was carried out using four low protein isonitrogenous diets (24% crude protein) formulated by supplementing varied levels of fish oil (0, 3, 6, and 9%). The diets were fed for 120 days at 5% body weight to triplicate groups of common carp (av. wt. 2.13-2.21 g) stocked at 1 per m2 in mud bottomed cement tanks (18 m2), fertilized with poultry manure. The growth of fish was the highest (P 0.05) from that of the control. Survival ranged from 96.29 (T1) to 100% (T0) without any significant (P > 0.05) difference among the treatments. While there was a general increase in amylase activity in the treated fish, protease activity showed a reduction with increase in oil supplementation. No difference (P > 0.05) in lipase activity was observed between the different treatments. The results indicate the beneficial effects of incorporating fish oil in the diet of common carp

Effects of a biodegradable substrate, sugarcane bagasse and supplemental feed on growth and production of fringe-lipped peninsula carp, Labeo fimbriatus (Bloch)

Substrate-based farming practices are considered viable low-cost technologies as they help in sustainable aquaculture production. This investigation of 90-day duration was carried out in mud-bottomed cement tanks to study the effect of substrate and/or feed on growth and production of fringe-lipped peninsula carp, Labeo fimbriatus. The treatments consisted of sugarcane bagasse (T1), sugarcane bagasse plus fish-meal based diet (T2), and fish-meal based diet (T3). The substrate addition affected water quality; it decreased total ammonia. Dissolved oxygen was low following manuring and introduction of the substrate, but improved subsequently. Total plate count of bacteria in water was higher in bagasse-based tanks; its value on bagasse was higher in T2 treatment than in T1. Fish growth and survival was the best in T2, followed by T3 and T1 treatments. Carcass proximate composition improved in all the treatments on termination of the experiment. The results indicate that L. fimbriatus effectively utilizes biofilm grown on sugarcane bagasse and provision of substrate reduces the need for artificial feed