Effects of freezing periods and polythene packaging with or without turmeric powder paste on proximate composition of Labeo bata fish

The study was designed to investigate the effects of freezing periods and the combination of packaging with or without turmeric on the proximate composition of whole and sliced Labeo bata. The samples were subjected to 28 days of frozen (-20 °C) storage periods and analyzed for proximate composition such as moisture, protein, lipid and ash at intervals of 0, 14 and 28 days. Data obtained was subjected to analysis of variance (ANOVA) at 95% significant level. Different preservation periods and methods significantly affected the nutritional composition of fresh fish. Moisture, protein, lipid and ash content decreased with increasing storage periods when compared to the fresh fish as control. The highest percentage of protein was found in turmeric-treated whole fish preserved in polythene, C4, after the 14th (15.70±0.14) and 28th (15.27±0.21) day. On the other hand, the lowest percentage (14.01±0.10 and 13.22±0.18 for the 14th and 28th day, respectively) was found in sliced fish preserved without polythene, C5. In conclusion, the turmeric-treated whole fish preserved in polythene retained fish nutrients and ensured its good quality and composition longer than other treatments, thereby extending the shelf life during frozen storage.

Influence of Stocking Density on Growth Performance of Labeo bata in Cage at River Padma, Rajshahi, Bangladesh

As a result of climate change, aquaculturists are seeking adaptive culture techniques for sustainable aquaculture. In this case, cage culture is a suitable technique that can mitigate the challenge of climate change, but due to the lack of knowledge of proper stocking density, often productions are not satisfactory. Therefore, the experiment was conducted to evaluate the influence of stocking density on growth and production of an endangered minor carp bata (Labeo bata) in cages for a period of 120 days in Padma River, Rajshahi, Bangladesh. On an average initial weight of bata fingerling of 5 g was stoked in cages under three treatments each with containing three replications using three different stocking densities (106, 71 and 35 fingerling/m3 for T1, T2 and T3, respectively). Supplementary feed (3% per body weight) was given to the cultured species twice in a day. The mean values of water temperature, transparency, pH and dissolved oxygen were in suitable range throughout the experimental period. Significantly (p<0.05) highest mean gross weight (85.82±0.70 g), specific growth rate (2.37± 0.02%), survival rate (83± 3.00%) and food conversion ratio (2.27± 0.03) was found in T3 rather than T2 and T1. The net production in terms of biomass (18.23±2.43 kg/cage) was significantly (p<0.05) higher in T2.The study suggests that, treatment T2 (71 fingerling /m3) as the optimum stocking density to produce maximum production by cage culture of Labeo bata.