An evaluation of the suitability of selected waste products in feeds for three fish species

Five types of aquatic food industry waste products (carp offal, carp roe, fish frames, trout offal and surimi processing waste) together with fish meal were evaluated for their suitability as potential fish meal replacements, partially or wholly, in diets for three species (rainbow trout, Murray cod and shortfin eel) cultured in Australia, using a number of criteria.The proximate composition of the ingredients on a dry matter basis including protein content, lipid and ash, varied considerably. The essential amino acid (EAA) contents of the waste products and fish meal decreased in the order: carp roe &gt; fish meal &gt; carp offal &gt; \u27surimi\u27 processing waste &gt; fish frames &gt; trout offal. The results of cluster analysis of A/E ratios of waste products and fish whole body fell within three clusters. The EAAI of whole body tissue of Murray cod, rainbow trout and Australian shortfin eel however, were closest to fish meal, followed by fish frame waste and/or \u27surimi\u27 waste. The results on A/E ratios and EAAI did not conform to the raw data on TAA and EAA. Therefore, the study emphasizes the need to have a multi-prong approach to determine the suitability of ingredients for incorporation into fish feeds.<br /

A Theory for the High-T_c Cuprates: Anomalous Normal-State and Spectroscopic Properties, Phase Diagram, and Pairing

A theory of highly correlated layered superconducting materials isapplied for the cuprates. Differently from an independent-electron approximation, their low-energy excitations are approached in terms of auxiliary particles representing combinations of atomic-like electron configurations, where the introduction of a Lagrange Bose field enables treating them as bosons or fermions. The energy spectrum of this field accounts for the tendency of hole-doped cuprates to form stripe-like inhomogeneities. Consequently, it induces a different analytical behavior for auxiliary particles corresponding to "antinodal" and "nodal" electrons, enabling the existence of different pairing temperatures at T^* and T_c. This theory correctly describes the observed phase diagram of the cuprates, including the non-Fermi-liquid to FL crossover in the normal state, the existence of Fermi arcs below T^* and of a "marginal-FL" critical behavior above it. The qualitative anomalous behavior of numerous physical quantities is accounted for, including kink- and waterfall-like spectral features, the drop in the scattering rates below T^* and more radically below T_c, and an effective increase in the density of carriers with T and \omega, reflected in transport, optical and other properties. Also is explained the correspondence between T_c, the resonance-mode energy, and the "nodal gap".Comment: 28 pages, 7 figure

Suplementação de taurina em dietas com duas concentrações proteicas para pós-larvas de camarão-branco-do-pacífico

Este estudo foi realizado com o objetivo de avaliar a possibilidade de reduzir a concentração proteica da dieta para pós-larvas de camarão-branco-do-pacífico (Litopenaeus vannamei) por meio da suplementação do aminoácido taurina. Seis dietas práticas, isoenergéticas (15,48 kJ EM/g), foram formuladas para conter duas concentrações de proteína (35% e 45% proteína bruta, PB), com três níveis de suplementação de taurina (0, 5 e 10 g/kg), em arranjo fatorial 2 × 3, com quatro repetições. Cem pós-larvas (peso inicial de 0,14 ± 0,01 g) foram estocadas em cada um dos 24 tanques de 45 litros conectados a um sistema de recirculação de água marinha. As dietas experimentais foram distribuídas aos camarões (10% da biomassa) três vezes ao dia, durante 30 dias. A concentração proteica da dieta não influenciou o crescimento nem a utilização alimentar das pós-larvas, mas o efeito benéfico da suplementação das dietas com taurina foi evidente em ambos os níveis proteicos testados. As póslarvas alimentadas com as dietas com maior concentração de taurina (10 g/kg) alcançaram maior peso final, ganho em peso e taxa de crescimento específico e melhor conversão alimentar em comparação àquelas alimentadas com as demais dietas. A taxa de sobrevivência média foi superior a 92% e não foi afetada pelas dietas experimentais. O nível de 35% de PB na dieta (22,58 mg PB/kJ EM) é suficiente para promover o crescimento adequado de pós-larvas de L. vannamei, e o desempenho dos camarões pode ser melhorado com a suplementação de 10 g taurina/kg de ração.The present study aimed to evaluate the possibility of reducing the dietary protein content for post-larvae of Pacific white shrimp (Litopenaeus vannamei) through diet supplementation with taurine amino acid. Six practical isoenergetic (15.48 kJ ME/g) diets were formulated to contain two protein concentrations (35% and 45% crude protein, CP) and 3 levels of taurine supplementation (0, 5 and 10 g/kg) in a 2 × 3 factorial scheme, with four replicates. One hundred postlarvae (initial weight 0.14 ± 0.01 g) were stocked in each of twenty-four 45–L tanks, connected with recirculating marine water system. Shrimps were fed the experimental diets (10% biomass) 3 times a day for 30 days. Dietary protein concentration did not influence growth neither feed utilization of the post-larvae, but a benefic effect of the diet supplementation with taurine on both protein levels tested was evident. Post-larvae fed diets with the highest taurine supplementation (10 g/kg) achieved significant higher final weight, weight gain, specific growth rate and better feed conversion than those fed the other diets. Average survival rate was greater than 92% and it was not affected by experimental diets. Crude protein level of 35% in the diet (22.58 mg CP/kJ ME) is enough to promote adequate growth of L. vannamei post-larvae and shrimp performance can be improved with supplementation of 10 g taurine/kg of ration