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

Performance of juvenile turbot (Scophthalmus maximus) fed varying dietary L-carnitine levels at different stocking densities

Commercial farming of turbot (Scophthalmus maximus) at high stocking densities may lead to growth depression and increasing production costs. Moreover, the high levels of accumulated waste in an intensive system may cause rapid deterioration of water quality, which may undermine the production. L-carnitine is known as a growth-enhancer which shows promise as mitigator of crowding effects. The effects of stocking densities (4, 8, 11 and 14 kg m²) on growth performance, feed utilization and body composition were evaluated during 75 days on turbot (75.6 ± 2.8 g) fed two dietary L-carnitine levels (40 or 240 mg kg¹). At the end of the feeding trial, total ammonia excretion (TAN) was measured postprandially for 24h. Specific growth rate and weight gain decreased with increasing stocking density. Fish held at 4 kg m² had higher final body weight (94-96 g) than fish held at higher densities (80-87 g). Protein efficiency ratio was higher in fish held at 4 kg m² (1.33-1.36), in comparison to fish stocked at 8 kg m² (0.98) or 14 kg m² (0.45). Voluntary feed intake decreased from 0.70 to 0.56% BW with increasing stocking density. Dietary L-carnitine supplementation did not affect growth performance and body composition, except for body L-carnitine content which increased from 75 to 128 mg kg¹ BW with supplementation. Fish fed 240 mg L-carnitine supplements had lower TAN that the ones fed 40 mg L-carnitine (p A aquicultura de pregado (Scophthalmus maximus) utilizando elevadas densidades pode reduzir o crescimento e aumentar os custos de produção. Elevados níveis de metabolitos gerados nestes sistemas intensivos provocam rápida deterioração da qualidade da água, podendo também comprometer a performance da produção. A L-carnitina atua como potenciadora do crescimento parecendo ser promissora por atenuar alguns desses efeitos. Os efeitos de densidades (4, 8, 11 e 14 kg m²) no desempenho do crescimento, composição corporal foram avaliados em pregados (75,6 ± 2,8 g) alimentados durante 75 dias a dois níveis dietéticos de L-carnitina (40 ou 240 mg kg¹). Após esse período, determinou-se a excreção de amônia pós-prandial durante 24 horas. Os peixes cultivados na menor densidade, 4 kg m², apresentaram melhores taxas de crescimento e ganho de peso (94-96 g) em comparação aos mantidos em altas densidades (80-87 g). A taxa de eficiência proteica foi mais elevada a 4 kg m² (1,33-1,36), do que a densidades de 8 kg m² (0,98) ou 14 kg m² (0,45). A ingestão voluntária de alimento decresceu de 0,70 para 0,56% do peso corporal com o incremento da densidade. A suplementação de carnitina não afetou o crescimento e a composição corporal, com exceção do conteúdo de carnitine da carcaça que passou de 75 a 128 mg kg¹. Peixes alimentados com suplementos de 240 mg L-carnitina apresentam excreção de amônia mais baixa comparativamente aos alimentados com 40 mg L-carnitina (p < 0,05)

Research on periphyton-based aquaculture in India.

AbstractThis review presents the results of periphyton-based aquaculture studies in India, and is divided into 8 sections. Following a brief introduction, the second section summarizes the results of the studies on plankton and periphyton productivity in terms of density and biomass. The third section discusses the results of fish production obtained in grow-out studies which aimed to evaluate the substrates, to compare fed and non-fed systems, and to standardize fish stocking density and the use of substrates in nursery rearing. The results of the studies on the utility of bacterial biofilm in fish health are summarized in the fourth section, and the effect of substrates on water quality parameters are presented in the fifth section. The information available on the digestibility of periphyton and the economics of periphyton-based fish culture using sugarcane bagasse as a substrate are presented on the sixth and seventh sections. The conclusion forms the last part of the review.</p

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

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

Growth response of Catlacatla (Hamilton,1822) raised in manured tanks on low fishmeal diets,with a note on carcass composition and digestive enzyme activity

Low fishmeal diets (10%) with varied levels of maize (40-31%) and sardine oil (0-9%) were fed for 120 days to triplicate groups of catla (Catla catla Hamilton,1822) fingerlings (average weight 1.84-1.90 g) stocked @ 1 fish per m2 in cement tanks with soil base fertilised with poultry manure. Fish fed on diet containing 6% oil and 34% maize (T2) showed the highest (p&lt;0.05) growth, followed by those received 9/31 (T3), 3/37 (T1) and 0/40% (T0) oil/maize supplemented diets. Food conversion ratio improved due to oil supplementation, while protein efficiency ratio was not affected significantly. Dietary lipid had a positive impact on carcass protein and lipid levels (p&lt;0.05). Fish survival ranged from 90.73% in all the treatment groups to 92.58% in the control, without any significant (p&gt;0.05) difference among them. Net fish production on termination of the experiment was lowest (820 g) in the control and the highest (1017.85 g) inT2 treatment. Viscerosomatic index (VSI) varied from 3.59 (T2) to 4.65% (T0) and hepatosomatic index (HSI) from 1.13 (T0) to 1.91% (T3). RNA/DNA ratio was highest (3.05) in T2 and lowest (1.84) in T0. An increase in intestinal amylase activity was observed in the treated fish, while intestinal protease and lipase activity showed increase only with higher levels of oil supplementation (6 and 9%). No difference (p&gt;0.05) in enzyme activity was observed in the hepatopancreas of the control and treated fish. The results indicated beneficial effects of incorporating maize and fish oil in low fishmeal diet for catla.</jats:p