A comparison of the palatability of racemic praziquantel and its two enantioseparated isomers in yellowtail kingfish Seriola lalandi (Valenciennes, 1833)

The bitterness of racemic praziquantel (Rac-PZQ) constrains its use as an in-feed treatment against monogenean flukes in finfish aquaculture. Evidence exists in mammals that the R-(-) enantiomer of PZQ is less bitter than the S-(+) enantiomer. If fish exhibit this same response, then the recently described techniques for the large-scale resolution of R-(-)-PZQ from Rac-PZQ could facilitate the wide-spread application of this effective anthelmintic compound via feed. The hypothesis that yellowtail kingfish Seriola lalandi would find R-(-)-PZQ more palatable than Rac-PZQ and S-(+)-PZQ was tested in four trials. During the first three trials, the palatability of diets top-coated with 10 g kg-1 of Rac-PZQ or its two enantioseparated isomers were compared in small (85-160 g) and large (1.2 kg) yellowtail kingfish. A fourth trial compared the palatability of R-(-)-PZQ and Rac-PZQ at dietary inclusion levels of 2.5, 5.0 and 10.0 g kg-1 in small yellowtail kingfish (170 g). Ingestion data showed that R-(-)-PZQ to be no more palatable than either Rac-PZQ or S-(+)-PZQ to yellowtail kingfish, regardless of size. Indeed, evidence suggested that the S-(+)-PZQ to be slightly more palatable than both R-(-)-PZQ and Rac-PZQ. From these data, we hypothesize that the strong smell of R-(-)-PZQ (which was not present in S-(+)-PZQ) is an equally important determinant to palatability as taste in yellowtail kingfish. Results demonstrate that dietary inclusion level is a more important determinant to palatability than PZQ chirality; however, administration of R-(-)-PZQ may still be advantageous if it is demonstrated to be the only enantiomer efficacious against monogeneans

Enzymatic fish protein hydrolysates in finfish aquaculture: A review

In intensive farming systems, fish are held at high densities, which may increase stress, leading to susceptibility to diseases that result in economic losses. Therefore, effective feeding practices incorporating health‐promoting compounds such as proteins, hydrolysates and bioactive peptides that can stimulate the defence mechanisms of fish and achieve better growth are some of the priorities for sustainable aquaculture development. Globally, the fish processing industries generate and discard a large volume of waste every year, estimated at up to 60% of the harvested biomass. This waste can be converted to value‐added products such as fish protein hydrolysate (FPH) with the addition of various proteolytic enzymes. FPH from fish processing waste including skin, heads, muscle, viscera, liver and bones is a good source of protein, amino acids, peptides and antioxidants and has been found to possess desirable functional and bioactive peptides. A moderate inclusion of FPH in aquafeeds has the potential to improve growth, feed utilization, immune functions and disease resistance of fish. Production of FPH, targeted to more precise molecular weight ranges, has superior functionalities that are in high demand. With interest in FPH as an aquafeed supplement, this review aimed to summarize the source, production processes and functional properties of FPH and the reported impact of FPH in aquafeed supplement on fish growth, survival, feed utilization, immune response and disease resistance. Possible limitations of using FPH and future research potential as an opportunity for the use of processing fish waste are also discussed

Factors required for the successful aquaculture of black bream (Acanthopagrus butcheri) in inland water bodies

The results of this project will contribute to the on-going development and success of inland black bream recreational fisheries and the inland saline aquaculture industry in general. Several commercial black bream fish-out ventures are now operational in inland Western Australia, one of which utilises saline groundwater. It has been proposed that a pilot project to stock the saline pools of the upper Avon River, which is located in the heart of the W.A. Wheatbelt, should be undertaken to provide recreational fishing opportunities for the inhabitants of a number of rural towns. The continued development of the W.A. inland saline aquaculture industry will result in social and economic benefits to rural areas through increased tourism and opportunities for farm diversification

Larval development of the western school prawn Metapenaeus dalli Racek, 1957 (Crustacea: Decapoda: Penaeidae) reared in the laboratory

The six Naupliar, three Protozoea, three Mysis and first post-larval forms of the western school prawn Metapenaeus dalli Racek, 1957 were cultured in the laboratory. These stages were described in detail and compared to those of other metapenaeids. The ontogenetic development occurred in 12 days at 26°C, with both the growth rate and morphological patterns of development in M. dalli broadly following those recorded for other metapenaeids. Differences were found between M. dalli and other metapenaeids at corresponding stages of larval development, with these being the number, location and composition of individual setae and other minor spinal development

Quantitative determination of ovarian development in penaeid prawns (Decapoda: Penaeidae)

We developed histological methods to increase precision in measuring oocyte size and, for the first time, quantify changes in oocyte composition during ovarian development in penaeids. Wild-caught female Metapenaeus dalli Racek, 1957 from the Swan-Canning Estuary, Perth, Western Australia were used as a model species to compare the novel method to traditional techniques. Morphological analysis showed that ovarian development in M. dalli occurs in five stages: immature, early maturing, late maturing, mature, and post spawning, which is consistent with other penaeids. Analysis of key morphometric parameters of length and Gonad Somatic Index (GSI) showed that GSI provided the strongest discriminators of ovarian development. Oogenesis was similar to qualitative descriptions of other penaeid prawns and most-closely related to previous descriptions of Metapenaeus affinis Milne Edwards, 1837. Comparisons between the novel perimeter tracing and traditional single linear methods for measuring oocyte dimensions showed that greater precision was achieved by tracing. This resulted in a 17-40% reduction in the confidence limits of the means for all cell types measured. A novel histological technique of examining oocyte composition was also developed. This technique allowed for the relationship between stages of ovarian development and proportion by volume of oocyte types to be determined. The difference in the proportions of cell types between each stage of ovarian development was found to be statistically significant, except between immature and post spawning females. The novel methods developed in this study provide new opportunities in the study of ovarian development in penaeids and possibly in other species

Automated phenotyping of mosquito larvae enables high-throughput screening for novel larvicides and offers potential for smartphone-based detection of larval insecticide resistance

Pyrethroid-impregnated nets have contributed significantly to halving the burden of malaria but resistance threatens their future efficacy and the pipeline of new insecticides is short. Here we report that an invertebrate automated phenotyping platform (INVAPP), combined with the algorithm Paragon, provides a robust system for measuring larval motility in Anopheles gambiae (and An. coluzzi) as well as Aedes aegypti with the capacity for high-throughput screening for new larvicides. By this means, we reliably quantified both time- and concentration-dependent actions of chemical insecticides faster than using the WHO standard larval assay. We illustrate the effectiveness of the system using an established larvicide (temephos) and demonstrate its capacity for library-scale chemical screening using the Medicines for Malaria Venture (MMV) Pathogen Box library. As a proof-of-principle, this library screen identified a compound, subsequently confirmed to be tolfenpyrad, as an effective larvicide. We have also used the INVAPP / Paragon system to compare responses in larvae derived from WHO classified deltamethrin resistant and sensitive mosquitoes. We show how this approach to monitoring larval response to insecticides can be adapted for use with a smartphone camera application and therefore has potential for further development as a simple portable field-assay with associated real-time, geo-located information to identify hotspots

The effect of a 24-hour photoperiod on the survival, growth and swim bladder inflation of pre-flexion yellowfin tuna (Thunnus albacares) larvae

The effects of two different continuous photoperiod regimes on survival, growth and swim bladder inflation of pre-flexion yellowfin tuna (Thunnus albacares) larvae were investigated. Each photoperiod regime was tested twice with a different larval cohort to confirm the observed results. Trials 1 and 2 tested the effect of a reduced night-time light intensity (10-molesm-2s-1=30% of the daytime intensity) and found that those larvae reared for 8days under the 24h lighting (24-L) photoperiod exhibited a slight improvement in survival compared to those reared under the control photoperiod of 12h light (12-L), however these improvements were not significant. In addition, those larvae reared under this photoperiod regime were equal in length to those in the control. Trials 3 and 4 compared the same variables in larvae reared under a continuous photoperiod (24-L) with a constant light intensity of 30-molesm-2s-1, against those reared under the aforementioned 12-L photoperiod. Survival of larvae under the continuous photoperiods were 9±1% (n=2) and 10±2% (n=3) for Trials 3 and 4, respectively, compared to less than 1% in both control treatments; differences that in both cases were highly significant. In addition, in both trials larvae cultured under the 24-L photoperiod were significantly larger and exhibited more advanced development than those reared under the 12-L photoperiod, however swim bladder inflation was significantly lower. We suggest that the improved survival and growth achieved under a continuous photoperiod is due to the extended foraging time combined with the prevention of mortality caused by night-time sinking

Search for Higgs bosons decaying to tautau pairs in ppbar collisions at sqrt(s) = 1.96 TeV

We present a search for the production of neutral Higgs bosons decaying into tautau pairs in ppbar collisions at a center-of-mass energy of 1.96 TeV. The data, corresponding to an integrated luminosity of 5.4 fb-1, were collected by the D0 experiment at the Fermilab Tevatron Collider. We set upper limits at the 95% C.L. on the product of production cross section and branching ratio for a scalar resonance decaying into tautau pairs, and we then interpret these limits as limits on the production of Higgs bosons in the minimal supersymmetric standard model (MSSM) and as constraints in the MSSM parameter space.Comment: 7 pages, 5 figures, submitted to PL

Measurement of three-jet differential cross sections d sigma-3jet / d M-3jet in p anti-p collisions at sqrt(s)=1.96 TeV

We present the first measurement of the inclusive three-jet differential cross section as a function of the invariant mass of the three jets with the largest transverse momenta in an event in p anti-p collisions at sqrt(s) = 1.96 TeV. The measurement is made in different rapidity regions and for different jet transverse momentum requirements and is based on a data set corresponding to an integrated luminosity of 0.7 fb^{-1} collected with the D0 detector at the Fermilab Tevatron Collider. The results are used to test the three-jet matrix elements in perturbative QCD calculations at next-to-leading order in the strong coupling constant. The data allow discrimination between parametrizations of the parton distribution functions of the proton.Comment: 10 pages, 4 figures, 2 tables, submitted to Phys. Lett. B, corrected chi2 values for NNPD

Search for pair production of the scalar top quark in muon+tau final states

We present a search for the pair production of scalar top quarks ($\tilde{t}_{1}$), the lightest supersymmetric partners of the top quarks, in $p\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV, using data corresponding to an integrated luminosity of {7.3 $fb^{-1}$} collected with the \dzero experiment at the Fermilab Tevatron Collider. Each scalar top quark is assumed to decay into a $b$ quark, a charged lepton, and a scalar neutrino ($\tilde{\nu}$). We investigate final states arising from $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\mu\tau \tilde{\nu} \tilde{\nu}$ and $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\tau\tau \tilde{\nu} \tilde{\nu}$. With no significant excess of events observed above the background expected from the standard model, we set exclusion limits on this production process in the ($m_{\tilde{t}_{1}}$,$m_{\tilde{\nu}}$) plane.Comment: Submitted to Phys. Lett.