Haemato-biochemical responses and induction of HSP70 to dietary phosphorus in <Emphasis Type="Italic">Catla catla</Emphasis> (Hamilton) fingerlings

A feeding trial of 120 days was conducted to study the effect of graded levels of dietary phosphorus on haematology, serum protein concentrations and HSP70 expression in fingerlings of the Indian major carp, Catla (Catla catla). Eight isonitrogenous and isoenergetic purified diets were formulated to contain graded levels of dietary phosphorus (dP), i.e., T₁, 0.1%; T₂, 0.3%; T₃, 0.5%; T₄, 0.7%; T₅, 0.9%; T₆, 1.1%; T₇, 1.3%; or T₈, 1.5%. Four hundred and eighty fish (average weight 4.23 ± 0.016 g) were equally distributed into 24 tanks forming eight treatments with three replicates each. The fish were fed daily at the rate of 3.5% body weight in two instalments. At the end of feeding trial fish were sampled to study total RBC and WBC count, haemoglobin, serum lysozyme activity, serum total protein, albumin (A), globulin (G) concentration and HSP70 expression. Total RBC count, haemoglobin concentration and serum lysozyme activity did not vary significantly in response to different dietary phosphorus concentrations. Total WBC count was found to be significantly (P < 0.05) higher in T₁ relative to all other treatments. Serum albumin and A/G ratio was found to be significantly lower in fish of T₁ and T₂ in relation to T₇ group (P < 0.05). Serum globulin and total protein levels remained unaffected by variations in dietary phosphorus. HSP70 expression was observed in T₁ group (0.1% dP) in gills and brain tissue, but not in liver and muscle tissues. No HSP70 expression was observed in fish of T₄ (0.7% dP) and T₈ (1.5% dP) treatments. These prima facie results suggest that dietary phosphorus had only minor influence on the haemato-biochemical parameters studied; however dietary phosphorus deficiency caused organ specific induction of HSP70 in catla fingerlings.     

Effects of stocking density and presence or absence of soil base on growth,weight variation,survival and body composition of pearlspot,Etroplus suratensis (Bloch) fingerlings

With the objective to develop an indoor tank seed rearing system for pearlspot (Etroplus suratensis), effects of three stocking densities in presence or absence of soil base were evaluated on growth, weight variation, survival and body composition in a 60‐day trial. The experiment had a 3 × 2 factorial design with three levels of stocking density (150, 300 and 450 fish m^?3) and two levels of soil base (with and without) in triplicates. Pearlspot fry (27.5 ± 0.5 mm/0.39 ± 0.02 g) were stocked in experimental tanks (Length×Breadth×Height: 0.65 × 0.50 × 0.48 m) and fed with a formulated diet containing 29.85% crude protein. Increasing the stocking density from 150 to 450 fish m^?3 significantly decreased the growth (average body weight and total length), daily weight gain, specific growth rate and survival (P < 0.001) and increased the feed conversion ratio (P < 0.01). Significantly lower growth and survival were observed in treatment having soil base compared with that of without soil base (P < 0.001). However, coefficients of variation at harvest weight and body composition of fingerlings were independent to stocking density and presence or absence of soil base (P > 0.05). A significant positive interaction effect of stocking density and presence or absence of soil base was observed on average body weight (P < 0.05) and survival (P < 0.001) of pearlspot fingerlings. This study suggests that stocking density of 150 fish m^?3 without soil base in tanks would be appropriate for raising pearlspot fingerlings in brackishwater indoor seed rearing system.     

Optimization of UV treatment to induce haploid androgenesis in the stinging catfish, Heteropneustes fossilis

We studied the microdistribution of the artificial radionuclide ²⁴¹Am in the components of Elodea canadensis - a submerged macrophyte of the Yenisei River. The alpha-track analysis showed that the microdistribution of ²⁴¹Am within different components of the submerged plant E. canadensis was not uniform. ²⁴¹Am distribution was found to be affected by the age of the leaf blades, state of the cells, and morphological features of the plant stem. The radionuclide ²⁴¹Am penetrated into the plant cells through the cell wall of E. canadensis, but it was accumulated in the vacuoles rather than in the cell wall or cytoplasm. In this case, the integrity of the cell membranes was not damaged.     

Immune responses and protection in rohu vaccinated against Aeromonas hydrophila infection

In this study, efficacy of three antigenic preparations from the fish pathogen Aeromonas hydrophila was evaluated as vaccine candidate in rohu Labeo rohita. The rabbit anti-rohu globulin conjugate was prepared in rabbit using sera obtained from healthy adult rohu. Three antigens, namely formalin inactivated A. hydrophila (FAH), FAH mixed with Freund’s incomplete adjuvant in a 1:1 (v/v) ratio (FAH + A), and extra cellular product were prepared. Protection of rohu against A. hydrophila infection was tested at days 10, 20, and 30 post-vaccination. At the end of the vaccination, fish were challenged with A. hydrophila (dose: 1 × 10⁷ cfu ml^?1) and relative per cent of survival was recorded up to 60th day of post-challenge. Study of cellular immunological parameters including antigen-specific leucocyte proliferation, antigen-specific nitric oxide production, and superoxide anion production exhibited significantly higher (p < 0.05) values on 10th and 20th day of post-vaccination compared with control. Among all the antigenic groups, FAH + A showed most significant responses compared with the other groups and produced maximum antibody on 30th day following vaccination. Among the humoral immune responses, lysozyme activity showed almost similar trend like cellular parameters. The result of the challenge study showed a higher level of survival in all the vaccinated groups, especially in FAH + A group. Our results suggest that vaccine FAH + A can effectively protect rohu against A. hydrophila infection and could offer an appropriate strategy to prevent this infection in rohu farms.     

Ammonia-oxidizing bacterial and archaeal communities in tropical bioaugmented zero water exchange shrimp production systems

Journal of Soils and Sediments - Ammonia oxidation is an important process in the removal of ammonia generated from feed and metabolic wastes in aquaculture systems. Considering the biogeochemical...     

Bio-mass Production in Potato in Relation to Evapotranspiration and Energy Summation Indices in Northern Hills of India

In field experiments conducted for 2 consecutive years at Shimla (31°06'N, 77°10'E at 2202 m above mean sea level with potato ( Solarium tuberosum L.), weekly means of rainfall (P), potential evapotranspiration (PET), pan evaporation (PAN) and photosynthetically active radiation (PAR) were estimated during the crop season. It was evident that from April to end of June, the evaporative demand was more than the precipitation and that the crop suffered from water deficit from emergence to tuber initiation. Four different energy summation indices accumulated over important phenological stages of growth and energy-use efficiency in terms of biomass production at these stages were estimated for two seasons. Weekly cumulative biomass production showed a significant correlation with accumulated PET, PAN and PAR in the four genotypes tested in year 2.     

Marine yeast glucans confer better protection than that of baker's yeast in Penaeus monodon against white spot syndrome virus infection

The immunostimulatory property of glucan isolates from three marine yeasts (Debaryomyces hansenii S8, Debaryomyces hansenii S169 and Candida tropicalis S186) and one Baker's yeast (Saccharomyces cerevisiae S36) as examined for potential application as immunostimulants in Penaeus monodon postlarvae against White Spot Syndrome Virus (WSSV) infection. Structural characterization of the glucan component in the isolates by proton nuclear magnetic resonance (NMR) indicated similar structures containing (1‐3)‐linked anhydroglucose repeat units (AGRUs) in the backbone with (1‐6)‐linked AGRUs in side chains that are (1‐6)‐linked to the backbone AGRUs. Glucan from C. tropicalis (S186) with the highest molecular weight and the lowest level of branching supported maximum survival (69%) followed by the other two marine yeast (S169 and S8) glucans of 27% and 23% respectively while glucan from Baker's yeast, S. cerevisiae S36 with the lowest molecular weight and the highest level of branching exhibited poor survival (4%) in P. monodon post challenge WSSV. The present study showed that the glucan isolate from marine yeast with a higher molecular weight and a lower degree of branching acts as better immunostimulants in P. monodon postlarvae than did the glucan isolate from S. cerevisiae.     

Induction of Diploid Androgenesis in the Stinging Catfish,Heteropneustes fossilis

This study reports the results on induced diploid androgenesis in the Indian catfish, Heteropneustes fossilis. Ultraviolet (UV) irradiation was used to inactivate maternal genome of H. fossilis. Complete inactivation of maternal genome was recorded at 12,500 ergs/mm². These genome‐inactivated eggs of H. fossilis were inseminated with conspecific sperm. The sperm suspension was diluted to 1 × 10⁷ sperm ml/L in Hank's Balanced Salt Solution. Egg viability was assessed for different exposure durations at fertilization, hatching, haploidy, and diploidization. Majority of the larvae derived from irradiated eggs had abnormal appearance. Complete inactivation of maternal genome was detected by haploid syndrome and confirmed by chromosome counting (n = 29). These eggs activated with sperm were subjected to heat shock at 40 and 41 C for different postactivation times and durations. Diploid androgens had a normal appearance as controls and confirmed by chromosome counting (n = 58). A maximum of 21 and 14% of diploidization was recorded at 30 min after activation, at 40 and 41 C, which corresponds to the first cleavage suppression time.     

Rheology and microscopic topology of entangled polymeric liquids

The viscoelastic properties of high molecular weight polymeric liquids are dominated by topological constraints on a molecular scale. In a manner similar to that of entangled ropes, polymer chains can slide past but not through each other. Tube models of polymer dynamics and rheology are based on the idea that entanglements confine a chain to small fluctuations around a primitive path that follows the coarse-grained chain contour. Here we provide a microscopic foundation for these highly successful phenomenological models. We analyze the topological state of polymeric liquids in terms of primitive paths and obtain parameter-free, quantitative predictions for the plateau modulus, which agree with experiment for all major classes of synthetic polymers.     

Diurnal changes in net photosynthetic rate in potato in two environments

Summary Diurnal changes in net photosynthetic rate were measured in a furrow-irrigated potato crop and in a riverbed crop where the water table was always maintained at 20–28 cm from the soil surface. In the irrigated crop, the photosynthetic rate during mid-afternoon was about half the peak rate observed at noon. This reduction was accompanied by a near tripling of stomatal resistance, a 45% reduction in transpiration, and a 5-fold increase in the difference between leaf and air temperatures. No such changes were observed in the riverbed crop where the photosynthetic rate remained nearly constant at about 0.9 mg m⁻² s⁻¹ between 9 a.m. and 4 p.m. Tuber yield in the riverbed crop was about 30% higher than in the irrigated crop.