Bopyrid isopods parasitizing on the cultured fresh water prawn, Macrobrachiummalcolmsonii in South India.

The bopyrid isopods are common in wild Macrobrachium spp. but not common in aquaculture condition. This is the first study that reports the parasitizing of bopyrid isopods on the cultured M. malcolmsonii. Bopyrid isopod (Probopyrus buitendijki) was identified in the branchial cavities of the fresh water prawn, M. malcolmsonii from grow-out culture pond at Kuriyamangalam, India. Macrobrachium malcolmsonii is a new host for P. buitendijki. A total of 1323 M. malcolmsonii were checked for this study. The overall prevalence of the parasitic infestation was reached 46.2 %. The parasitic infection was higher in female (83 %) than in male (3.4 %). Highest prevalence of infestation was found in the median size group (7-8 cm) (58.7 %). Infected females were not berried unlike uninfected prawns. The parasites cause infertility and does not found any organ deformities due to the infestation. The parasite was inversely attached in the gill chamber with no lesion on the gill but the infected branchial chamber became bulged.

Effect of legume seed extracts on the inhibition of proteolytic activity and muscle degradation of fresh water prawn (Macrobrachiumrosenbergii).

Trypsin inhibitors in the extracts from soybean (Glycine max), adzuki bean (Vigna angularis), bambara groundnut (Vigna subterranea) and red kidney bean (Phaseoulus vulgaris) varied in amount and molecular weight. The soybean extract had the highest level of trypsin inhibitor with molecular weight (MW) of 21kDa, followed by bambara groundnut extract possessing trypsin inhibitor with MW of 15kDa. Both extracts showed a more effective inhibition towards crude protease extract (CE) from the hepatopancreas of fresh water prawn (Macrobrachium rosenbergii) than the extracts from adzuki and red kidney beans. Activity staining also reconfirmed the higher inhibitory activity on CE from hepatopancreas by the extracts from both soybean and bambara groundnut. The extracts from all seeds were able to inhibit the degradation of fresh water prawn meat containing CE in a concentration dependent manner. Based on inhibitor study, the extracts from soybean and bambara groundnut can be a potential aid to suppress the muscle softening of fresh water prawn, mediated by trypsin-like proteases released from hepatopancreas, during extended iced storage.

Growth of fresh-water prawn Macrobrachium tenellum (Smith, 1871) juveniles fed isoproteic diets substituting fish meal by soya bean meal

Growth parameters (standard length, weight, specific growth rate and daily weight gain) of prawn Macrobrachium tenellum juveniles fed 40 percent crude protein isoproteic diets substituting fish meal with soya bean meal at various levels (20, 40, 60, 80 and 100 percent) were evaluated for 45 days under laboratory conditions. Experimental diets were compared with a 100 percent fish meal based diet. Total survival was recorded for all the treatments at the end of the experiment. There were no significant differences (p > 0.05) for all the growth parameters among the dietary treatments. The initial mean weight (0.36 ± 0.10 g) increased almost three times (1.00 ± 0.13 g) after 45 days. The final specific growth fluctuated from 1.82 percent BW/d for the 60 percent soya bean meal inclusion diet, to 2.62 percent for the 100 percent fish meal diet. The mean final survival was 91.66 percent. Growth performance of M. tenellum juveniles was not affected by the dietary soya bean meal levels tested.

Os parâmetros do crescimento (comprimento padrão, peso, taxa de crescimento específica e ganho diário do peso) de juveniles do Macrobrachium tenellum alimentaram a 40 por cento a proteína crua as dietas isoproteic que substituem a refeição de peixes com feijão de soya a refeição nos vários níveis (20, 40, 60, 80 e 100 por cento) foi avaliada por 45 dias sob condições do laboratório. As dietas experimentais foram comparadas com uma dieta baseada da refeição de peixes de 100 por cento. A sobrevivência total foi gravada para todos os tratamentos no fim da experiência. Não havia nenhuma diferença significativa (p > 0.05) para todos os parâmetros do crescimento entre os tratamentos dietéticos. O peso médio inicial (0.36 ± 0.10 g) aumentado quase três vezes (1.00 ± 0.13 g) após 45 dias da cultura. O crescimento específico final flutuou de 1.82 por cento BW/d para a dieta do inclusion da refeição do feijão de soya de 60 por cento, a 2.62 por cento obtidos para a dieta da refeição de peixes de 100 por cento. A sobrevivência final média foi de 91.66 por cento. O desempenho do crescimento de juveniles do M. tenellum não foi afetado pelos níveis dietéticos da refeição do feijão de soya testados.