Search

A field study evaluated the safe loading density for live transportation of rainbow trout, Oncorhynchus mykiss (Walbaum, 1792), yearlings in plastic bags of super-oxygenated water. The experimental fish (197.5 ± 40 g) were starved for 72 h and mildly sedated with clove oil (40 µL.L-1 for 2–3 min) before packing. Three loading densities of live rainbow trout (120, 170, 230 g.L-1) were packed in plastic bags containing 6 L of stream water and 10–12 L of medical-grade oxygen gas. Six replicate bags per loading density were then subjected to 10 h of transportation by road at ~10 °C. On arrival at the destination, important water quality indicators and fish survival were recorded from each plastic bag. With increasing fish loading density, there was a corresponding increase in the concentrations of carbon dioxide (CO2), total ammonia nitrogen (TAN), free ammonia (NH3), total dissolved solids (TDS) concentrations and specific conductivity in the transport water, and a decrease in dissolved oxygen (DO, R² = 0.91-0.99). These differences in vital water quality indicators were significantly more in the 230 g.L-1 group. However, there was no mortality even at the highest loading density, as the critical water quality parameters did not cross the acute lethal thresholds for rainbow trout. Based on the findings, it is recommended that a loading density of 230 g.L-1 is safe for live transportation of rainbow trout yearlings in plastic bags over a transport duration of 10 h at ~10 °C, following adequate starvation and mild sedation. [ABSTRACT FROM AUTHOR]

The enhancement of immunity of fish through application of natural immunostimulants would help in minimizing the risk of occurrence of diseases in aquaculture. The present study was designed to evaluate the growth promoting and immunostimulatory effect of Guduchi, Tinospora cordifolia (Thunb.) Miers ex Hook F. leaf powder in fingerlings of Amur carp (Cyprinus carpio haeYnatopterus Martens). The fingerlings were divided into four treatment groups, Ti, T2, T₃ and T₄. Experimental diets were prepared by mixing rice bran, deoiled mustard cake, soybean meal and vitamin mineral mixture. The leaf powder of T. cordifolia was incorporated into diets D₂, D₃, and D₄ @ 0.25%, 0.5% and 0.75%, respectively. In control diet D₁, leaf powder of T. cordifolia was not incorporated. T₁ group fishes were fed with D, diet, T2 with D₂, T₃ with D₃ and T₄ with D₄ @ 5% body weight per day for 90 days. Fingerlings fed with diet D₄ achieved significantly improved Specific Growth Rate (1), Feed Conversion Ratio (2.76), and Gross Conversion Efficiency (0.361) as compared .to the control and all other treatments (P <0.05). Hematological and biochemical parameters, total leuckocyte count (53.849x103/[L), total erythrocyte count (3.50x106/iL), hemoglobin concentration (17.17%), total serum protein, albumin and globulin (12.35, 1.56 and 10.78 g/dL) in D₄ diet fed fishes showed increase as compared to the control and all other treatments (P <0.05). The above research revealed that Tinospora cordifolia leaf powder has significant growth promoting and immunostimulatory potential in Amur carp raising.