Improving culture techniques for village-based farming of giant clams (Tridacnidae)

Eight experiments aimed at improving methods for the village-based farming of giant clams were conducted in the Solomon Islands. The experiments focused on either improving the fitness of seed clams delivered to village farmers, assessing whether differential growth rates of seed clams in nursery tanks persisted during grow-out at farms, or testing the effects of alterations to the design of grow-out cages on the growth and survival of clams. We found that Tridacna squamosa (Lamarck) ‘seed’ transferred from land-based nursery tanks to a floating ocean nursery (FON) for ≈ 3 months at the end of the nursery phase were significantly larger than seed reared only in land-based nursery tanks. Similarly, T. maxima (Röding) placed in a FON for 2–5 months generally grew at a significantly greater rate than tank-reared ‘seed’. However, the use of FONs did not improve survival. There were no consistent differences in the growth and survival of fast- and slow-growing seed of T. derasa (Röding) at village sites when slow-growing seed were retained in the nursery until reaching a larger size. The survival of T. maxima was enhanced significantly by placing an insert of smaller mesh (a ‘settlement ring’) in grow-out cages for the first 2 months after delivery of seed to farmers. The settlement ring retained clams in cages until they found a suitable place to attach their byssal threads. Attempts to remove the sediment which impedes the attachment of T. maxima to the base of grow-out cages by perforating the substrate did not improve survival: the perforated substrate resulted in poor attachment of clams and harboured predators (Cymatium spp.). The survival of T. crocea (Lamarck) was not improved by ‘softening’ the concrete base of grow-out cages to simulate dead coral rock and to encourage the clams to burrow in the substrate. The survival of T. crocea in grow-out cages was enhanced significantly by enclosing the cages in fine mesh after the delivery of the seed clams to prevent predation and disturbance by juvenile wrasse, Thalassoma spp. The experiments indicate that the critical stage for village farming of giant clams is during the initial weeks following distribution of seed. Further research is needed to improve the survival of T. crocea and T. maxima during this phase.     

At-line near-infrared spectroscopy for prediction of the solid fat content of milk fat from New Zealand butter

Near-infrared (NIR) spectroscopy calibrations that will allow prediction of the solid fat content (SFC) of milk fat extracted from butter by one measurement during manufacture were developed. SFC is a measure of the amount of the solid fraction of fat crystallized at a temperature expressed as a percentage (w/w). At-line SFC determinations are currently performed by nuclear magnetic resonance (NMR) spectroscopy, which involves a 16 h delay period for tempering of the milk fat at 0 degrees C prior to the SFC measurements, from 0 to 35 degrees C in a series of 5 degrees C increments. The NIR spectra (400-2500 nm) were obtained using a sample holder maintained at 60 degrees C. Accurate predictions for the SFC (%) were developed by principal component analysis (PCA) and partial least-squares (PLS) regression models to relate the NIR spectra to the corresponding NMR values. The independent validation samples (N = 22) had a standard error of prediction (SEP) of 0.385-0.762% for SFC between 0 and 25 degrees C, with SFC reference values ranging between 70.42 and 8.96% with a standard deviation range of 3.36-1.47. The low bias (from -0.351 to -0.025), the slopes (0.935-1.077), and the excellent predictive ability (R2; 0.923-0.978) supported the validity of these calibrations.     

Mass spectrometric determination of the predominant adrenergic protoalkaloids in bitter orange (Citrus aurantium)

The predominant adrenergic protoalkaloid found in the peel and fruit of bitter orange, Citrus aurantium, is synephrine. Synephrine is reputed to have thermogenic properties and is used as a dietary supplement to enhance energy and promote weight loss. However, there exists some concern that the consumption of dietary supplements containing synephrine or similar protoalkaloids may contribute to adverse cardiovascular events. This study developed and validated a positive-ion mode liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the quantitative determination of the major (synephrine) and minor (tyramine, N-methyltyramine, octopamine, and hordenine) adrenergic protoalkaloids in a suite of National Institute of Standards and Technology (NIST) bitter orange Standard Reference Materials (SRMs): SRM 3258 Bitter Orange Fruit, SRM 3259 Bitter Orange Extract, and SRM 3260 Bitter Orange Solid Oral Dosage Form. The limit of quantitation (LOQ) for all protoalkaloids is approximately 1 pg on-column, except for octopamine (20 pg on-column). Additionally, the method has a linear dynamic range of > or =3 orders of magnitude for all of the protoalkaloids. Individual, as well as "total", protoalkaloid levels (milligrams per kilogram) in the NIST SRMs were determined and compared to the levels measured by an independent liquid chromatography/fluorescence detection (LC/FD) method. Satisfactory concordance between the LC/MS/MS and LC/FD protoalkaloid measurements was demonstrated. LC/MS/MS analysis of the protoalkaloids in the SRMs resulted in mean measurement imprecision levels of < or =10% coefficient of variation (% CV).     

Cricothyroid muscle function and vocal fold stability in exercising horses

OBJECTIVES: To determine (1) if the cricothyroid muscle had respiratory-related electromyographic (EMG) activity that increased with respiratory effort and (2) if bilateral cricothyroid myotomy resulted in vocal fold instability and collapse in exercising horses. STUDY DESIGN: Experimental. ANIMALS: Seven (3 EMG; 4 cricothyroid myotomy) Standardbred horses. METHODS: Three horses exercised on a treadmill at speeds corresponding to the speed that produced maximum heart rate (HR(max)), 75% of maximum heart rate (HR(75%max)), and 50% of maximum heart rate (HR(50%max)) for 60 seconds at each speed while EMG activity of the cricothyroid muscle and nasopharyngeal pressures were measured. Another 4 normal horses were exercised on the treadmill at HR(max) and HR(75%max) for 60 seconds at each speed before and after bilateral cricothyroid myotomy. Upper airway pressures were measured and videoendoscopic examinations were performed and videotaped at each speed. RESULTS: Peak phasic EMBG activity of the cricothyroid muscle was coincident with inspiration and increased with treadmill speed. Bilateral cricothyroid myotomy resulted in vocal fold collapse in all horses. Mean peak inspiratory pressures were significantly more negative compared with control values at both HR(max) and HR(75%max). CONCLUSIONS: Cricothyroid muscle dysfunction may be implicated in vocal fold collapse and likely causes inspiratory airway obstruction in exercising horses. CLINICAL RELEVANCE: Conditions compromising cricothyroid muscle function or motor innervation could result in vocal fold collapse.     

Carbon loads, forms and sequestration potential within ash deposits produced by wildfire: new insights from the 2009 ‘Black Saturday’ fires, Australia

Forest fires release substantial amounts of carbon (C). Much of it is emitted to the atmosphere, but some is deposited within ash on the ground. Little is known about amount and types of C deposited in ash. Here, we quantify total C, and total inorganic, water-soluble and particulate organic fractions deposited in ash during the catastrophic 2009 ‘Black Saturday’ wildfires in Australia. These fires coincided with the highest air temperatures and lowest humidity ever recorded in the local area, which, combined with high fuel loads of mostly long unburnt eucalypt forests, generated extreme burning conditions. In three mixed-species eucalypt forest sites sampled, the canopy, understorey and litter fuels were almost completely consumed, resulting in substantial ash deposition (mean, 81.9 t ha^?1), with 5.9 t ha^?1 of C being transferred from vegetation to the forest floor. In five temperate rainforest sites sampled, the canopy was not burnt and ash deposition was lower (mean, 48.3 t ha^?1) than in the mixed-species eucalypt forest, but overall their higher C content resulted in higher C deposition (8.1 t ha^?1). In all cases, most C contained in ash was organic and its pyrogenic nature infers increased resistance to degradation. Pyrogenic C is viewed by many as an important C sink, which could contribute to long-term C sequestration when incorporated into soils or sediments. Our results highlight the potential importance of the pyrogenic C pool in freshly deposited ash and, therefore, the necessity of a systematic and detailed analysis of ash deposition and C forms in ash to improve our understanding of C fluxes by forest fires.     

Hypoosmotic Swelling Test in Alpaca (Vicugna pacos) Epididymal Spermatozoa

The present study intended to develop the hypoosmotic swelling (HOS) test in alpaca for its use in epididymal spermatozoa, to evaluate the membrane functional integrity and determine an appropriate hypoosmotic solution and whether the incubation time of 15 or 60 min is sufficient for the execution of the test. Hypoosmotic solutions (HS) with the following concentrations were used: 50, 100, 150, 200 and 275 mOsm/kg of sodium citrate tribasic dihydrate and d ‐fructose. Ten microlitres of epididymal sperm sample was mixed in 150 μL of the respective HS and incubated for 15 or 60 min at 38°C. From the proportion of reacted (swollen) spermatozoa, the 150 mOsm/kg HS was the most sensitive (p < 0.05). The exposure times (15 and 60 min) did not have significant differences (p > 0.05) in the proportion of both strong‐ and total‐coiled sperm tails. In conclusion, 150 mOsm/kg HS and 15 min exposure time are optimal to evaluate the plasma membrane functional integrity through the HOS test in alpaca epididymal spermatozoa.     

The Effect of Glycerol Concentrations on the Post‐thaw In Vitro Characteristics of Cryopreserved Sex‐sorted Boar Spermatozoa

The objective of this study was to optimize protocols for the cryopreservation of sex‐sorted boar spermatozoa. In the experiment 1, we evaluated the effects of a standard boar sperm cryopreservation procedure (3% final glycerol concentration) on the in vitro characteristics of sex‐sorted sperm frozen at low sperm concentrations (20 × 10⁶ sperm/ml; S20 group). Non‐sorted spermatozoa frozen at 1000 × 10⁶ (C1000 group) and 20 × 10⁶ (C20 group) sperm/ml were used as the freezing control groups. In experiment 2, the effects of different final glycerol concentrations (0.16%, 0.5%, 1.0%, 2.0% and 3.0%) on post‐thaw quality of the S20 and C20 groups were evaluated. In both experiments, the samples were evaluated prior to freezing (5°C) and at 30, 90 and 150 min after thawing. Experiment 1 indicated that freezing sperm at low concentrations decreased (p < 0.05) the total motility (TM) and progressive motility (PM) at 90 and 150 min after thawing regardless of whether the sperm were sorted or not. However, the sperm membrane integrity was not affected at any evaluation step. Inexperiment 2, significant effects on the TM and PM because of increased glycerol concentrations in the S20 and C20 groups were observed only at 90 and 150 min after thawing. The samples frozen in 3% glycerol showed lower (p < 0.05) TM and PM values when compared to those frozen in the presence of 0.5% and 1% glycerol. In both experiments, non‐sorted control samples displayed higher percentages of spermatozoa with damaged DNA than sorted spermatozoa. In conclusion, the optimization of cryopreservation conditions by decreasing the glycerol concentrations can improve post‐thaw motility of sex‐sorted spermatozoa frozen at low concentrations.     

Post operative infection, pyrexia and perioperative antimicrobial drug use in surgical colic patients

Reasons for performing study: Infections are common complications in post operative colic patients. It is the impression of some surgeons that pyrexia in the early post operative period is a sign of infection and appropriate timing of perioperative antimicrobials will decrease the incidence of post operative infection. Objective: To determine the association between 1) post operative pyrexia and development of infection and 2) perioperative antimicrobial drug use and infection rate in post operative colic patients. Methods: Medical records of patients undergoing surgical treatment for colic were reviewed. Horses recovering from surgery and surviving >48 h were included. Data relating to case details, duration of surgery, post operative infection, peri‐ and post operative antimicrobial administration, presence, intensity and duration of pyrexia, were recorded. Data were analysed using standard statistical methods for simple comparisons between groups and by logistic regression for more complex comparisons. Results: One‐hundred‐and‐thirteen horses were included in the final analyses, 48 (43%) of which were diagnosed with a post operative infection. Duration of surgery and anaesthesia were associated with post operative infection. Eighty‐five percent of horses (n = 96) exhibited pyrexia (rectal temperature >38.3°C) post operatively. Peak temperature >39.2°C, time post surgery to peak temperature >48 h and duration of pyrexia >48 h were significantly associated with infection. In a combined model, time to first pyrexic >48 h post surgery, peak temperature and time to peak >48 h were equally weighted and the model's positive predictive value for post operative infection was 72%. Timing and dose rate of preoperative antimicrobials were not associated with infection but duration of post operative antimicrobial drug use was. Conclusion and clinical relevance: Slight to mild pyrexia (38–39.4°C) in the early post operative period is not necessarily associated with impending bacterial infection in colic patients and the use of antimicrobials in these patients may be costly and unnecessary.