The study was conducted to observe the impact of commercial probiotics application on growth and production performance of fresh water prawn (Macrobrachium rosenbergii) from August 2011 to March 2012. There were four experimental groups viz (a) control or without probiotics treated prawn (T1), (b) feed probiotics- Zymetin (T2) treated prawn, (c) soil probiotics- Super PS (T3) treated prawn and (d) Both Zymetin and Super PS (T4) treated prawn. Twelve ponds (each 120m2) were used where stocking density was 2/m2 for all treatments and control and each was triplicated. After pond preparation, prawn PL was reared in the nursery pond for 45days to become juvenile. At the time of stocking in growout ponds, average body weight of juvenile prawn was 1.04g. After eight months (240days) of culture, the mean final weight became 39.5±12.03, 43.4±14.91, 48.0±16.73 and 51.6±15.58g in T1, T2, T3 and T4 respectively. Significance difference was found among all treatments and T4 showed highest growth. The SGR was found to be 1.50±0.13, 1.53±0.13, 1.58±0.13 and 1.61±0.11 (%BW/day) in T1, T2, T3 and T4 respectively and the difference was significant. The survival rate did not differ significantly but highest survival rate was found in T4 (90%). The average FCR was significantly lowest in T4 (1.39) and highest in T1 (1.9). The net average production was found to be significantly higher in T4 (914kg/ha) which was 35% and 21 % higher than the control group (T1) and feed probiotics (T2) respectively. Water and soil quality parameters were measured and were within the culturable range. The production of probiotics treated ponds was always higher than without probiotics treated ponds but highest growth and production were found in T4 where Zymetin and Super PS were used combinedly. The results of this study can be applied in the farmer’s pond to increase the total production of prawn in the country

This study evaluates the effect of probiotics, Zymetin, on the immune efficiency of Macrobrachium rosenbergii juvenile against pathogenic Vibriospp. and Aeromonasspp. The experiment was conducted in glass aquaria with same level of feeding under different treatments, that is, negative control (Cn), positive control with Vibrio spp. (Cv) and Aeromonasspp. (Ca), prawn juveniles fed with probiotics (Zymetin) at 5 g/kg of feed but without pathogen (T1), probiotic fed prawn challenged with Vibrio spp. (T2) and Aeromonasspp. (T3). The results demonstrated that T1 showed higher survival rate, total haemocyte count, non‐granular haemocyte count, phagocytic activity, and clearance efficiency compared to other treatment groups. In contrast, decreased number of small and large granular haemocyte was observed in T1. Despite that, THC was found to be significantly different (p < 0.05) among all the controls and lowest was in Cv, followed by Ca. Besides, phagocytic activity and clearance efficiency against Vibrio spp. and Aeromonasspp. decreased significantly in Cn, Ca, and Cv fed M. rosenbergiijuvenile, while the values were found to be higher in T1 followed by T2 and T3, in that order. In addition, the challenge test showed an increasing trend of total and beneficial bacterial density as well as declining trend of some harmful bacteria in the water and gut of prawn in all the groups tested (p < 0.05).

This study was carried out to estimate the sex ratio, maturity size, gonadosomatic index (GSI), and peak breeding season of mud crabs. Samples were collected randomly from the estuary and river of the study area. Sampling was carried out monthly from April to September at every full moon during one high tide. A total number of 240 specimens were sampled, where 53 individuals were hermaphrodite. The crabs were shifted alive to the biology and histology lab for detailed biological study. Sex was determined. Male and female sex ratio and breeding season were also investigated. The male:female ratio was 1:0.96 and the ovarian development was categorized into five stages based on internal observations, viz. immature (stage I), underdeveloped (stage II), early developed (stage III), late developed (stage IV), and mature (stage V). The maturity percentages were 37%, 19%, 13%, 11%, and 20%, respectively. 50% maturation was estimated at 82.36 mm internal carapace width (ICW). The highest mean GSI value was 7.97 ± 3.03. The mature stage was found in all the working periods. This shows that females have activated ovaries in all the working months, and the species are continuous breeders. A higher frequency of vitellogenic ovary and higher GSI value were found in September. The maximum GSI value was found in the size group 70–79 mm. The study shows that the capture from the wild sources of mud crabs without any regulation can threaten the population structure. The capture of female mud crabs should be more than 82.36 mm ICW, which will help conserve and protect young crabs.