Effects of Temperature on Growth and Protein Assimilation in Juvenile Leader Prawns Penaeus monodon

Abstract.— The effects of temperature on growth and protein assimilation in leader prawns Penaeus monodon were evaluated. Growth of leader prawns was significantly ( P < 0.05) affected by temperature. The highest growth rate was 0.124 g/d at 32.0 C and optimum growth occurred between 27.5–32.0 C. Growth was described by an equation of the form: W _t = W_oe^kt ( R² = 0.99). The relationship between temperature and growth was described by a curvilinear equation of the form: Y = a + bX + cX² ( R² = 0.70). Apparent protein assimilation efficiency was not significantly ( P > 0.05) affected by temperature.     

Equilibrative nucleoside transporter 3 deficiency perturbs lysosome function and macrophage homeostasis

Lysosomal storage diseases (LSDs) are a group of heterogeneous disorders caused by defects in lysosomal enzymes or transporters, resulting in accumulation of undegraded macromolecules or metabolites. Macrophage numbers are expanded in several LSDs, leading to histiocytosis of unknown pathophysiology. Here, we found that mice lacking the equilibrative nucleoside transporter 3 (ENT3) developed a spontaneous and progressive macrophage-dominated histiocytosis. In the absence of ENT3, defective apoptotic cell clearance led to lysosomal nucleoside buildup, elevated intralysosomal pH, and altered macrophage function. The macrophage accumulation was partly due to increased macrophage colony-stimulating factor and receptor expression and signaling secondary to the lysosomal defects. These studies suggest a cellular and molecular basis for the development of histiocytosis in several human syndromes associated with ENT3 mutations and potentially other LSDs.     

Pulmonary pharmacokinetics of tulathromycin in swine. Part I: Lung homogenate in healthy pigs and pigs challenged intratracheally with lipopolysaccharide of Escherichia coli

The objective of the study was to assess the pharmacokinetics of tulathromycin in lung tissue homogenate (LT) and plasma from healthy and lipopolysaccharide (LPS)‐challenged pigs. Clinically healthy pigs were allocated to two dosing groups of 36 animals each (group 1 and 2). All animals were treated with tulathromycin (2.5 mg/kg). Animals in group 2 were also challenged intratracheally with LPS from Escherichia coli (LPS‐Ec) 3 h prior to tulathromycin administration. Blood and LT samples were collected from all animals during 17‐day post‐tulathromycin administration. For LT, one sample from the middle (ML) and caudal lobes (CL) was taken. The concentration of tulathromycin was significantly lower in the ML after the intratracheal administration of LPS‐E. coli (P < 0.02). In healthy pigs and LPS‐challenged animals, the distribution of the drug into the lungs was rapid and persisted at high levels for 17‐day postadministration. The distribution of the drug within the lung seems to be homogenous, at least between the middle and caudal lobes within dosing groups. The concentration versus time profile of the drug and pharmacokinetic parameters in two different lung areas (middle and caudal lobe) were consistent within the groups. The clinical significance of these findings is unknown.     

Weaning requirements of larval mulloway,Argyrosomus japonicus

Mulloway (Argyrosomus japonicus) is an emerging aquaculture species in Australia, but there is a need to improve the production technology and lower costs, including those associated with larval rearing and live feeds. Three experiments were conducted to determine appropriate weaning strategies from live feeds, rotifers (Brachionus plicatilis) and Artemia, to cheaper formulated pellet diets. Experiment 1 examined the effects of feeding Artemia at different levels [0%, 50% or 100% ration of Artemia fed from 18 days after hatching (dah); based on current hatchery protocols] and a pellet diet from two larval ages (14 or 23 dah). In addition, rotifers were supplied to larvae in all treatments for the duration of the experiment (14–29 dah), at which time all larvae were successfully weaned onto the pellet diet. No significant (P>0.05) differences existed between the growth of fish fed a 50% and 100% ration of Artemia; however, fish fed a 0% ration of Artemia had significantly (P<0.05) reduced growth. The time of pellet introduction had no significant (P>0.05) effects on the growth of larvae. Experiments 2 and 3 were designed to determine the size [total length (TL), mm] at which mulloway larvae selected Artemia equally or in preference to rotifers, and pellet (400 μm) equally or in preference to Artemia respectively. Each day, larvae were transferred from a holding tank to experimental vessels and provided with rotifers (2 mL^?1), Artemia (2 mL^?1) or a combination of rotifers (1 mL^?1) and Artemia (1 mL^?1) (Experiment 2), and Artemia (2 mL^?1), a pellet diet or a combination of Artemia (1 mL^?1) and a pellet diet that was broadcast every 15 min (Experiment 3). After 1 h, a sub‐sample of larvae was randomly selected from each replicate vessel (n=5) and the gut contents were examined under a light microscope. Mulloway larvae began selecting Artemia equally to rotifers at 5.2 ± 0.5 mm TL and selected pellets equally to Artemia at 10.6 ± 1.8 mm TL. Our results have led to the establishment of weaning protocols for larval mulloway, which optimize larval growth while reducing feed cost by minimizing the amount of Artemia used during production.     

Spawning site fidelity and apparent annual survival of walleye (Sander vitreus) differ between a Lake Huron and Lake Erie tributary

Fidelity to spawning habitats can maximise reproductive success of fish by synchronising movements to sites of previous recruitment. To determine the role of reproductive fidelity in structuring walleye Sander vitreus populations in the Laurentian Great Lakes, we used acoustic telemetry combined with Cormack–Jolly–Seber capture–recapture models to estimate spawning site fidelity and apparent annual survival for the Tittabawassee River in Lake Huron and Maumee River in Lake Erie. Walleye in spawning condition were tagged from the Tittabawassee River in Lake Huron and Maumee River in Lake Erie in 2011–2012. Site fidelity and apparent annual survival were estimated from return of individuals to the stream where tagged. Site fidelity estimates were higher in the Tittabawassee River (95%) than the Maumee River (70%) and were not related to sex or fish length at tagging. Apparent annual survival of walleye tagged in the Tittabawassee did not differ among spawning seasons but was higher for female than male walleye and decreased linearly as fish length increased. Apparent annual survival of walleye tagged in the Maumee River did not differ among spawning seasons but was higher for female walleye than male walleye and increased linearly as fish length increased. Greater fidelity of walleye tagged in the Tittabawassee River than walleye tagged in the Maumee River may be related to the close proximity to the Maumee River of other spawning aggregations and multiple spawning sites in Lake Erie. As spawning site fidelity increases, management actions to conserve population structure require an increasing focus on individual stocks.     

Swimbladder inflation associated with body density change and larval survival in southern bluefin tuna Thunnus maccoyii

High mortality of southern bluefin tuna (SBT) Thunnus maccoyii larvae in captivity is a major problem hindering culture of this species. The relationships between body density of SBT larvae, swimbladder inflation and survival were investigated in this study. Swimbladder inflation and changes in volume have a direct effect on body density in larval SBT. Swimbladder inflation was first observed at 3 days post hatch, and larvae with successful swimbladder inflation were able to maintain their body density within a narrow range (?ρ = 0.0006 g cm^?3). Although swimbladder volume increased with larval growth, it could not compensate for the increase in body density and did not prevent nocturnal sinking. The increase in body density was greater for larvae that did not inflate their swimbladder. Low percentages of swimbladder inflation (27.5 ± 3.5 %) coupled with negative body buoyancy of SBT might contribute to mortality as larvae sank in the dark phase and made contact with the tank bottom. Management strategies that maintain larvae within the water column and enhance swimbladder inflation are required to improve survival of SBT larvae reared in hatcheries.     

Biochemical characterisation of some non fermenting, non arginine hydrolysing mycoplasmas of ruminants

The pattern and kinetics of substrate oxidation by type and recent field strains of Mycoplasma agalactiae, Mycoplasma bovis, Mycoplasma bovigenitalium and Mycoplasma ovine/caprine serogroup 11 were investigated by measurement of oxygen uptake. Metabolism of a range of organic acids, sugars and alcohols was detected. All the test strains were unable to oxidise sugars, glycerol and the organic acids, fumarate, malate and alpha-ketoglutarate (1 mM). All strains oxidised organic acid l-lactate, 2-oxobutyrate and pyruvate and demonstrated the ability to oxidise alcohols, particularly isopropanol, which was oxidised at a high rate and high affinity (0.5 mol/mol isopropanol). Its oxidation was consistent with acetone formation, which may be of important in relation to pathogenicity. All strains oxidised similar substrates, however differences were observed between strains in terms of the relative rates and kinetic values for some substrates.     

A novel medium devoid of ruminant peptone for high yield growth of Mycoplasma ovipneumoniae

Mycoplasma ovipneumoniae is considered an emerging veterinary pathogen causing pneumonia in sheep and goats worldwide. Currently it has not been possible to define a growth medium that yields the maximum growth of M. ovipneumoniae within a short incubation period. Growth yields of M. ovipneumoniae in Eaton's medium are variable and not as consistently high as those seen with other Mycoplasma spp. This study investigated the ability of different M. ovipneumoniae field strains to grow in various media formulations, where PPLO broth was replaced by a vegetable protein source, and comparisons were made in terms of strain viability in Eaton's medium. Studies were also conducted to determine the optimal carbohydrate source for use in the M. ovipneumoniae medium. Generally, it was found that different strains showed good growth in all media tested, with growth yields at 24h in TSB-1 medium higher than those observed with Eaton's medium. Growth yields reached 10(8) to 10(9)cfu ml(-1) within 24h for particular field strains, with all strains achieving this growth level within 48-72h.     

Synthesis of deuterated gamma-lactones for use in stable isotope dilution assays

Two syntheses of deuterated gamma-lactones for use as internal standards in stable isotope dilution assays (SIDA) were developed. [2,2,3,3-2H4]-gamma-Octa-, -gamma-deca-, and -gamma-dodecalactones with >89% deuterium incorporation were prepared in 27, 17, and 19% overall yields, respectively, by the reduction of a doubly protected hydroxypropiolic acid with deuterium gas. [3,3,4-2H3]-gamma-Octa- and -gamma-dodecalactones were prepared in 6 and 23% yields with >92% deuterium incorporation by the free radical addition of 2-iodoacetamide to [1,1,2-2H3]-1-hexene and [1,1,2-2H3]-1-decene, respectively. Reaction yields were highly dependent upon the purity of the 1-alkene starting material. The deuterated gamma-lactones were evaluated as internal standards for SIDA.