Protein requirement of juvenile Penaeus indicus 1. Food consumption and growth

Juveniles of Penaeus indicus were fed with different concentrations of protein diet (0--60% of dry weight of diet) with purified lipid free casein as protein source. During the experimental period of 30 days, survival was only 27% in the group fed with protein free diet. Survival (75%) and protein efficiency ratio (3'7) were maximum at 40 and 30% proteirilevel, respectively; specific food consumption (4-3-6'7%) and food conversion ratio (1-3-1'4) were lowest at 30 and 40% protein level, respectively. Another experiment conducted to precisely quantify the near optimum protein requirement for maximum growth of Penaeus indicus revealed significantly higher growth and protein efficiency ratio in the groups receiving 35-37'5% protein than the other groups

Optimising the Active Sonar System Design

Designing an optimum sonar system for a given platform is based on analysing various parameters in their totality, establishing the constraints and assumptions relevant to the platform and the environment as well as on manipulating the design parameters to arrive at the sonar configuration that will maximise performance. In this paper, the design tradeoffs involved in the system design for an active sonar are discussed. A computer aided analysis for the 'first order' estimation of the sonar performance is presented. Typical results of the analysis in connection with the design for certain hypothetical systems are also included

Determination of digestibility coefficient

Nutrients present in the feedstuffs are not completely available to the animal body. Large portions of the nutrients are excreted In the faeces because of being not digested In the alimentary tract. Therefore, the digestibility of the feedstuff is defined as the portion of a feed or nutrient of feed which is not recovered In faeces, i.e., the portion which has been absorbed by the animal. When the digestibility is expressed in percentage it is known as digestibility coefficient. Digestibility coefficients are calculated for dry matter, crude protein, crude fibre, ether extract and nitrogen-free extract. Digestibility of gross energy present in the food can also be determined. The digestibility coefficients normally determined are the apparent digestibility coefficients since the nutrients found in the faeces contain small proportion of nutrients from the previously utilized food In the form of mucosal debris, unspent enzymes ate

Importance of anabolic agents, binders, antioxidants and mould inhibitors in fish and prawn feeds

Binders, antioxidants, mould inhibitors and growth promoters are non-nutritional additives added in the feeds. The chemical compound choosen of the purpose should be neither toxic, nor antimetabolic, nor mutagenic, nor carcinogenic, nor teratogenic and nor bioaccumulative. Secondly must be effective at minimal concentration. Thirdly should neither retard growth, nor reduce palatability, appetite and assimilation of dietary nutrients. Fourthly should not react with the feed ingredients chemically in a way that would alter the nutritional quality of the feed adversely. Should be economical, And lastly should not reduce the quality of the meat produced by way of affecting taste, appearance, flavour and texture

Growth, Structural and Micro hardness studies of KSbF4 and K2SbF5 crystals

Interest in Potassium Fluoro Antimonate crystals has been increased for the last four decades due its superionic conduction and its unusual electro-optic properties. Potassium tetra fluoro antimonate (KSbF4) and Potassium penta fluoro antimonite (K2SbF5) crystals have been grown by slow evaporation method. KSbF4 crystallizes into orthorhombic structure with a space group Pmmn. K2SbF5 belongs to orthorhombic crystal system with a space group Cmcm.nbsp Micro indentation analysis on these crystals indicates that they are moderately softer substances. Both crystals revealed reverse indentation size effect (RISE). Variation of stiffness constant with load has been discussed. Yield strength for KSbF4 and K2SbF5 crystals have been found out as 16.72 and 16.941 MPa respectively.nbs

Selection of specific cell wall antigen for rapid detection of fish pathogenic Vibrio parahaemolyticus by enzyme immunoassay

An enzyme linked immunosorbant assay (ELISA) was developed, using polyclonal antibodies against a specific cell surface protein of Vibrio parahaemolyticus, for rapid detection of the organism. Nine virulent strains and one type strain of V. parahaemolyticus, one strain each of Vibrio vulnificus and Vibrio alginolyticus were used for the study. Cell surface proteins were extracted from all the strains and were analysed by SDS PAGE. One distinct band with molecular weight of 34 kDa, abundant in all the V. parahaemolyticus strains and lacks in other Vibrio species, was selected as cell wall antigen for immunisation. Polyclonal antibodies were raised against the selected 34 kDa protein of V. parahaemolyticus after preparative electrophoresis. An indirect plate ELISA was developed using this antiserum for detection of crude cell surface protein as well as whole cells of V. parahaemolyticus. All the 9 virulent strains and one type strain of V. parahaemolyticus tested, produced positive results, using the ELISA technique. To assess the specificity of the polyclonal serum, cross reaction studies with other Vibrio species such as V. vulnificus and V. alginolyticus were conducted by indirect plate ELISA. The results have clearly shown that antibodies directed against 34 kDa cell surface protein can be used for specific detection of fish pathogenic V. parahaemolyticus

Superconductivity in Ru substituted BaFe2-xRuxAs2

The occurrence of bulk superconductivity at ~22 K is reported in polycrystalline samples of BaFe2-xRuxAs2 for nominal Ru content in the range of x=0.75 to 1.125. A systematic suppression of the spin density wave transition temperature (TSDW) precedes the appearance of superconductivity in the system. A phase diagram is proposed based on the measured TSDW and superconducting transition temperature (TC) variations as a function of Ru composition. Band structure calculations, indicate introduction of electron carriers in the system upon Ru substitutiom. The calculated magnetic moment on Fe shows a minimum at x=1.0, suggesting that the suppression of the magnetic moment is associated with the emergence of superconductivity. Results of low temperature and high field Mossbauer measurements are presented. These indicate weakening of magnetic interaction with Ru substitutionComment: 20 pages 10 figure

Development of a Cell Culture System From Gill Explants of the Grouper, Epinephelus malabaricus (Bloch and Shneider)

A cell culture system was developed successfully from gill explants of the Malabar grouper, Epinephelus malabaricus. Gill tissue samples aseptically excised from healthy juveniles of E. malabaricus were explanted in Leibovitz’ L-15 medium supplemented with 0.07 M NaCl and 20% fetal bovine serum (FBS). A mixture of different types of cells emerged from the explants, and these cells were observed to spread and attach to the culture flasks from the second day onwards. Confluent monolayers comprising epithelioid as well as fibroblast-like cells were formed within ten days. The cells were found to grow well at 28 + 2°C. The cell monolayers were subcultured by trypsinization and seeded into new flasks, which produced confluent monolayers comprising predominantly epithelioid-like cells in subsequent passages