Metamorphosis Induction of the Dog Conch Strombus canarium (Gastropoda: Strombidae) Using Cues Associated with Conch Nursery Habitat

Strombus canarium is a commercially important gastropod that has great potential for advancement into aquaculture. In this study, the metamorphosis response of Strombus canarium larvae to various metamorphosis cues associated with conch nursery habitat and to KCl and GABA, were tested. Bioassays were run as static, no choice experiment and adopting a continuous exposure approach. Strombus canarium larvae showed strong metamorphosis responses when sediment (i.e., conch nursery habitat sediment/SD-NU) and detrital substrata (i.e., Thalassia detritus leachate/T-LC) from their nursery habitat were used (p<0.05). There was no metamorphosis in treatments using sterilized conch nursery habitat sediment (SD-ST) and sediment taken from outside conch nursery habitat (SD-OT). Experiments using fresh macrophyte blades of Enhalus acoroides (EA), Thalassia hemprichii (TH), Halophila ovalis (HA) and Ulva (UL) and adult conditioned seawater (SD-SW) also showed negative respond. Conch larvae demonstrate active habitat selection during metamorphosis and no spontaneous metamorphosis was observed. Settlement in S. canarium is associative in nature where epibionts associated with conch nursery habitat could be the cue for the metamorphosis. However, the specific epibionts/inducers and mechanisms underlining the process were not studied and therefore are subjected to more detailed investigation. The use of KCl was comparable with treatments using natural inducers (SD-NU and T-LC), thus was suggested for application in hatchery spat production of the species

Effects of temperature on food consumption of juveniles dog conch, Laevistrombus canarium (Linnaeus, 1758) in laboratory condition

The dog conch, Laevistrombus canarium (Linnaeus, 1758) is one of the economically important marine molluscs that have high market value, particularly in the Southeast Asian region. This study investigates food consumption and assimilation by the juvenile conch at different temperature regimes (22, 26, 30 and 34°C). Live samples of the juvenile conch were collected on several occasions between December 2013 to May 2105 at Merambong shoal, Johor Straits, Malaysia. They were acclimatized for one week in stocking aquaria with well-aerated seawater at 30 PSU, 26°C and fed with commercial marine sinking pellets. Prior to experimentation, the gastric emptying levels of the samples were standardized by allowing them to feed until satiation, followed by 24 hrs starvation. All treatments were carried out in ten replicates of similar sized aquarium (20 x 15 x 15 cm) containing 4L of aerated seawater. The conch food consumption rate was significantly different (p<0.05) between different temperature regimes. The food absorption efficiency was also affected by different temperature regimes (P<0.05), and ranged between 50.14% to 73.76%. The food energy absorbed were then calculated, which showed significant variations between temperatures (P<0.05). Based on these calculations, higher food consumption and assimilation were recorded at 26°C followed by 30, 34 and 22°C. Results from this study allow us to predict the optimal temperature regimes (26°C) for the culture of these marine sea snail L. canarium. Further studies are indeed, needed to provide a better insight on the effect of climate change parameters on these species

Influence of environmental parameters on shrimp post-larvae in the Sungai Pulai seagrass beds of Johor Strait, Peninsular Malaysia

Monthly sampling for shrimp post-larvae was conducted between April 2007 and March 2008 from the seagrass beds of Sungai Pulai Estuary, Johor, Peninsular Malaysia. Samples were collected from sub-surface using a bongo net equipped with a flow meter. In situ environmental parameters such as water temperature, dissolved oxygen, pH, salinity, total dissolved solid and conductivity were recorded during each sampling time. Total catch was comprised of four major taxa namely:Lucifer (94.9%), Acetes (1.52%), Penaeus (0.13%) and Mysis (0.06%). Mean density of shrimp post larvae (PL) was calculated as 22,614.74 individuals/100 m3. Peak abundance of Penaeus was found in June to July, while Acetes was found throughout the year with peak abundance in September. Higher abundance ofLucifer compared to the other genus was observed throughout the year with peaks in the monsoon months (May to July and October to December). The occurrence and abundance of Mysis was also restricted only in the monsoon months (November to January and May to July). There were significant correlation between the abundance of shrimp PL and in situ environmental parameters in the study area

Evapotranspiration and crop coefficients of rice (Oryza sativa L.) under sprinkler irrigation in a semiarid climate determined by the surface renewal method

The evapotranspiration (ETc) of sprinkler-irrigated rice was determined for the semiarid conditions of NE Spain during 2001, 2002 and 2003. The surface renewal method, after calibration against the eddy covariance method, was used to obtain values of sensible heat flux (H) from high-frequency temperature readings. Latent heat flux values were obtained by solving the energy balance equation. Finally, lysimeter measurements were used to validate the evapotranspiration values obtained with the surface renewal method. Seasonal rice evapotranspiration was about 750–800 mm. Average daily ETc for mid-season (from 90 to 130 days after sowing) was 5.1, 4.5 and 6.1 mm day−1 for 2001, 2002 and 2003, respectively. The experimental weekly crop coefficients fluctuated in the range of 0.83–1.20 for 2001, 0.81–1.03 for 2002 and 0.84–1.15 for 2003. The total growing season was about 150–160 days. In average, the crop coefficients for the initial (Kcini), mid-season (Kcmid) and late-season stages (Kcend) were 0.92, 1.06 and 1.03, respectively, the length of these stages being about 55, 45 and 25 days, respectively

Temperature induced variation in oxygen consumption of juvenile and adult stage of the dog conch Laevistrombus canarium (Linnaeus 1758)

Laevistrombus canarium Linnaeus, 1758 is one of the important edible sea snail within the western Johor Straits, Malaysia. In this study, the impact of temperature on oxygen consumption (MO2) of L. canarium based on their ontogenetic changes (juvenile and adult) was measured in the laboratory condition at 22.0, 26.0, 30.0 and 34.0°C. Measurement of MO2 were taken every 1 s for 60 min on 4.20 – 34.00 g dog conch using respirometry chamber. All experiments were carried out in static conditions in five replicates with one snail per chambers. The results of oxygen consumption showed that juvenile dog conch respired at the rate of 0.163 ml h−1 and adult respired at the rate of 0.119 ml h−1. Consequently, the oxygen consumption in juvenile and adult dog conch was expressed as a total energy spends. The results indicates that total energy spend for oxygen consumed (ml h−1) of L. canarium at different temperature regimes (22.0 to 34.0°C) slightly increased over time period (0.63 ± 0.12 to 3.24 ± 0.05 J h−1) respectively. This finding of the present study suggested L. canarium is well adapted for life in high temperature environment

The role of cover crops in irrigated systems: Soil salinity and salt leaching

Soil salinity and salt leaching are a risk for sustainable agricultural production in many irrigated areas. This study was conducted over 3.5 years to determine how replacing the usual winter fallow with a cover crop (CC) affects soil salt accumulation and salt leaching in irrigated systems. Treatments studied during the period between summer crops were: barley (Hordeum vulgare L.), vetch (Vicia villosa L.) and fallow. Soil water content was monitored daily to a depth of 1.3 m and used with the numerical model WAVE to calculate drainage. Electrical conductivity (EC) was measured in soil solutions periodically, and in the soil saturated paste extracts before sowing CC and maize. Salt leaching was calculated multiplying drainage by total dissolved salts in the soil solution, and use to obtain a salt balance. Total salt leaching over the four winter fallow periods was 26 Mg ha−1, whereas less than 18 Mg ha−1 in the presence of a CC. Periods of salt gain occurred more often in the CC than in the fallow. By the end of the experiment, net salt losses occurred in all treatments, owing to occasional periods of heavy rainfall. The CC were more prone than the fallow to reduce soil salt accumulation during the early growth stages of the subsequent cash crop

Effect of mineral-enriched diet and medicinal herbs on Fe, Mn, Zn, and Cu uptake in chicken

<p>Abstract</p> <p>Background</p> <p>The goal of our study was to evaluate the effects of different medicinal herbs rich in polyphenol (Lemon balm, Sage, St. John's wort and Small-flowered Willowherb) used as dietary supplements on bioaccumulation of some essential metals (Fe, Mn, Zn and Cu) in different chicken meats (liver, legs and breast).</p> <p>Results</p> <p>In different type of chicken meats (liver, legs and breast) from chickens fed with diets enriched in minerals and medicinal herbs, beneficial metals (Fe, Mn, Zn and Cu) were analysed by flame atomic absorption spectrometry. Fe is the predominant metal in liver and Zn is the predominant metal in legs and breast chicken meats. The addition of metal salts in the feed influences the accumulations of all metals in the liver, legs and breast chicken meat with specific difference to the type of metal and meat. The greatest influences were observed in legs meat for Fe and Mn. Under the influence of polyphenol-rich medicinal herbs, accumulation of metals in the liver, legs and breast chicken meat presents specific differences for each medicinal herb, to the control group that received a diet supplemented with metal salts only. Great influence on all metal accumulation factors was observed in diet enriched with sage, which had significantly positive effect for all type of chicken meats.</p> <p>Conclusions</p> <p>Under the influence of medicinal herbs rich in different type of polyphenol, accumulation of metals in the liver, legs and breast chicken meat presents significant differences from the group that received a diet supplemented only with metal salts. Each medicinal herb from diet had a specific influence on the accumulation of metals and generally moderate or poor correlations were observed between total phenols and accumulation of metals. This may be due to antagonism between metal ions and presence of other chelating agents (amino acids and protein) from feeding diets which can act as competitor for complexation of metals and influence accumulation of metals in chicken meat.</p> <p><b>Graphical abstract</b></p

Growth of the purple dye murex, Bolinus brandaris (Gastropoda: Muricidae), marked and released in a semi-intensive fish culture earthen pond

The present study reports the growth rate of the purple dye murex, Bolinus brandaris (Gastropoda: Muricidae), estimated from mark-recapture experiments. A total of 1067 specimens (shell length = 43.4±8.1 mm, range = 14.6−78.4 mm) were marked with Dymo® tape tags and released in a semi-intensive fish culture earthen pond. After a period at liberty ranging from almost two months to around two years, 288 individuals were recaptured (shell length = 67.4±6.2 mm, range = 45.3−88.6 mm), which corresponded to a recapture rate of 27.0%. At recapture, only one specimen had lost the tag (tag loss rate <0.1%) and all remaining tags were intact and legible. Mean monthly growth rates were 0.9±1.0 mm in shell length, 0.4±0.5 mm in shell width and 0.7±0.7 g in total weight. Growth rates showed high inter-individual variability and an evident decreasing trend with specimen size. Comparison of growth rates with similar information available for other muricids confirmed that B. brandaris is a relatively slow-growing species. This provides valuable information for both fisheries management and for assessing the potential of B. brandaris as a candidate species for molluscan aquaculture.Crecimiento de la cañailla, Bolinus Brandaris (Gastropoda: Muricidae), mediante técnicas de marcado-recaptura realizadas en estanques de cultivo semiintensivo de peces. – Se ha estudiado el crecimiento de la cañailla Bolinus brandaris (Gastropoda: Muricidae) mediante técnicas de marcado-recaptura. Se marcaron un total de 1067 individuos (longitud concha = 43.4±8.1 mm, rango = 14.6−78.4 mm) con etiquetas plásticas Dymo, que fueron puestos en libertad en un estanque en tierra dedicado al cultivo semiintensivo de peces. En el plazo de tiempo comprendido entre dos meses y dos años, se recuperaron 288 ejemplares (longitud concha = 67.4±6.2 mm, rango = 45.3−88.6 mm), lo que corresponde a una tasa de recaptura del 27.0%. Las etiquetas permanecieron intactas y legibles en todos los ejemplares recuperados, a excepción de un único individuo (tasa de pérdida de marca <0.1%). La tasa de crecimiento media mensual estimada fue de 0.9±1.0 mm de longitud, 0.4±0.5 mm de anchura y 0.7±0.7 g de peso total. Esta tasa muestra una elevada variabilidad intraespecífica y una tendencia clara a la disminución con el aumento de la talla. Comparando las tasas de crecimiento obtenidas en este estudio con la información disponible sobre diversas especies de murícidos, se confirma que B. brandaris es un gasterópodo de crecimiento relativamente lento. Este estudio resulta de interés tanto para gestionar la pesca de este recurso como para evaluar el potencial de la especie como candidata a ser cultivada.publishe

Management of acromegaly in Latin America: expert panel recommendations

Although there are international guidelines orienting physicians on how to manage patients with acromegaly, such guidelines should be adapted for use in distinct regions of the world. A panel of neuroendocrinologists convened in Mexico City in August of 2007 to discuss specific considerations in Latin America. Of major discussion was the laboratory evaluation of acromegaly, which requires the use of appropriate tests and the adoption of local institutional standards. As a general rule to ensure diagnosis, the patient’s GH level during an oral glucose tolerance test and IGF-1 level should be evaluated. Furthermore, to guide treatment decisions, both GH and IGF-1 assessments are required. The treatment of patients with acromegaly in Latin America is influenced by local issues of cost, availability and expertise of pituitary neurosurgeons, which should dictate therapeutic choices. Such treatment has undergone profound changes because of the introduction of effective medical interventions that may be used after surgical debulking or as first-line medical therapy in selected cases. Surgical resection remains the mainstay of therapy for small pituitary adenomas (microadenomas), potentially resectable macroadenomas and invasive adenomas causing visual defects. Radiotherapy may be indicated in selected cases when no disease control is achieved despite optimal surgical debulking and medical therapy, when there is no access to somatostatin analogues, or when local issues of cost preclude other therapies. Since not all the diagnostic tools and treatment options are available in all Latin American countries, physicians need to adapt their clinical management decisions to the available local resources and therapeutic options