No abstract

Five iso-energetic (15.05 MJ kg )1 ) semi-purified diets with graded levels of crude protein, i.e. 200 (D-1), 250 (D-2), 300 (D-3), 350 (D-4) and 400 (D-5) g kg )1 diet were fed to Puntius gonionotus fingerlings (average weight 0.88 ± 0.03 g) in triplicate groups (15 healthy fish per replicate) for a period of 90 days to determine the optimum protein requirement of the fish. Fifteen flowthrough cement tanks of 100-L capacity with a flow rate of 0.5 L min )1 were used for rearing the fish. Specific growth rate (SGR), food conversion (food gain) ratio (FCR), nutrient digestibility and retention, digestive enzyme activity, RNA : DNA ratio and tissue composition were used as response parameters with respect to dietary protein levels and feed intake. The mean weight gains of fish after 90 days were 10.84 ± 0.27, 11.07 ± 0.12, 14.09 ± 0.20, 11.27 ± 0.12 and 10.91 ± 0.25 g for D

A 30-day study was undertaken to examine the proteinsparing effect of carbohydrate in diets for silver barb, Puntius gonionotus fry. Six semi-purified experimental diets were formulated with two levels of protein (200 and 250 g kg )1 diet) and three levels of carbohydrate (300, 340 and 380 g kg )1 diet). In addition to the six experimental diets, a diet containing the protein and carbohydrate requirement levels of 300 and 260 g kg )1 diet, respectively, as reported earlier for this species, was used as a reference diet. For each dietary treatment, 30 healthy fry of 20 days age (0.12 ± 0.01 g) were stocked in triplicate tanks using a flowthrough system. The fish were fed ad libitum four times a day to a level close to apparent satiation. Batch weighing of fish was done after 15 days of stocking to measure growth and general health status of the fish. The fish fed 250 g protein and 340 g carbohydrate kg )1 diet with a protein to energy ratio of 17.86 g protein MJ )1 performed equally well in terms of growth and nutrient utilization as the reference diet group. The study indicates that dietary protein can be reduced from 300 to 250 g kg )1 diet by increasing carbohydrate from 260 to 340 g kg )1 diet without sacrificing the growth of silver barb fry. KEY WORDS

A comprehensive acute toxicity trial was conducted using a static water system to study the toxic effect of ammonia on haematology and enzyme profiles of Cirrhinus mrigala H. The LC50 of total ammonia‐nitrogen (TAN) was 11.8 mg L−1 TAN (1.029 mg L−1 NH3‐N). The sub‐lethal test revealed that with increasing concentration of TAN, the total erythrocyte counts were reduced in lower concentrations (1–4 mg L−1 TAN) followed by higher levels in fish exposed to higher concentrations (8–16 mg L−1 TAN). In contrast, the total leucocyte counts were opposite. With increasing concentration of TAN, haemoglobin and serum protein content were reduced, whereas the blood glucose level increased. As the concentration of ammonia increased, there was a reduction in acetylecholinesterase activity in the brain and liver; alkaline phosphatase activity in the serum, brain and gill; and acid phosphatase (ACP) activity in the gill. The activity of lactate dehydrogenase in the gill, liver, kidney and brain increased with increased concentration of ammonia. In addition, activities of ACP in the serum and brain, alanine aminotransferase in the serum, brain and gill, and aspartate aminotransferase in the serum, brain and gill were increased.

DNA barcoding was successfully used for the accurate identification of chondrichthyans in the Indian commercial marine fishery. About 528 specimens of 111 chondrichthyan species and 34 families, collected from the Indian EEZ, were barcoded for a 655 bp region of the mitochondrial gene cytochrome c oxidase subunit 1 (COI). Generally, five specimens per species were barcoded, but numbers ranged from 2 to 13. The average Kimura 2 parameter (K2P) distance separating individuals within species was 0.32%, and the average distance separating species within genera was 6.73%. Ten species were suggested as putative new species requiring formal descriptions. Based on the morphology and molecular support, 11 elasmobranch species were confirmed first records for Indian waters. The present study confirms the ability of DNA barcoding for the accurate identification of sharks, rays, and their products from Indian waters.