The Effect of Low Salinity Water with Different Ionic Composition on the Growth and Survival of Litopenaeus vannamei (Boone, 1931) in Intensive Culture

The effects of four different ionic composition low salinity water (T₁, T₂, T₃, and T₄), on growth and survival of Litopenaeus vannamei marine shrimp juveniles were investigated. Shrimp culture in seawater (T_m) was used as control treatment. The results indicated that there were no significant difference (P < 0.05) in growth, survival, production, and feed conversion ratio (FCR) of L. vannamei juveniles reared in the different treatments, but significant differences (P < 0.05) were observed between each of them when compared with seawater (T_m). After 84 days, culture shrimp grew from 0.02 to 7.58 g in T₁. The lowest growth rate was attained in T₃ (0.57 g/week), in which potassium and calcium ions concentrations were the lowest (0.58 and 28.00 mg/L, respectively). The recorded survival rate (76.35% to 79.55%) is considered well for the 84 days growout period, although it was 7.6% lower than that recorded in the control treatment. Although there were no significant differences (P < 0.05) in growth with respect to the ionic composition of the four treatments, there was a trend of increasing growth in relation with the ionic ratio found in the seawater (T_m). This aspect should be evaluated more closely in future research.     

Allergenic Content of New Alimentary Pasta Made of Lentils Compared with Lentil Seeds and Analysis of the Impact of Boiling Processing

Plant Foods for Human Nutrition - There is growing interest in legumes such as lentil as healthy ingredients in gluten-free products. In that respect, foods based on lentils, like alimentary pasta,...     

Post-pollen-germination barriers to seed set in sweet-potato

Three sweet-potato crossing combinations selected for good pollen germination were characterized by a moderate to high amount of failure of tubes to pass from stigma to style. The number of tubes penetrating the style was about 6 times the number of seeds produced. Ovules of compatibly pollinated flowers were divided into two classes, by size. Larger (probably fertilized) ovules matured into seeds, whereas smaller (probably unfertilized ovules) dried into scales. Besides the incompatibility barrier in sweet potato, which inhibits pollen-germination, a physiological or mechanical barrier between stigma and style is hypothesized. Pollen tube growth is not appreciably inhibited within the style. A third barrier between stylar penetration and mature seed development is postulated but not identified. However, the mechanism does not appear to be due to embryo abortion. Seed abortion leads to small, weak and inviable seeds, and thus represents a further reproductive loss.     

Effect of L‐tryptophan supplemented diets on serotonergic system and plasma cortisol in Totoaba macdonaldi (Gilbert, 1890) juvenile exposed to acute stress by handling and hypoxia

Brain serotonin and cortisol play a central role in integrating the neuroendocrine response to stress. Previous studies in aquatic species show that dietary supplementation with the 5‐HT precursor L‐tryptophan amino acid is able to modulate this response. The aim of this study was to evaluate the effect of dietary tryptophan (Trp) on the serotonergic system and acute stress response in Totoaba macdonaldi. Four groups of fish were fed with one of four isonitrogenous and isocaloric diets formulated with different Trp content: 0.5% (1X TRP, control diet), 1.1% (2X TRP), 1.7% (3X TRP) and 2.3% (4X TRP). After a feeding period of 21 days, groups were exposed to acute stress by handling with a net or hypoxia. Feeding with Trp‐enriched diets resulted in increased 5‐HT content in telencephalon of undisturbed fish. Handling increased the 5‐hydroxyindole acetic acid (5‐HIAA) and serotonin turnover (5‐HIAA/5‐HT) in telencephalon of fish fed with 1X TRP and 2X TRP but was not significant for the fish fed 3X TRP and 4X TRP, and no significant increase was observed by hypoxia in both telencephalon and hypothalamus in any of the diets. An inverted U‐shaped response was observed in plasma cortisol increasing with 2X TRP after both handling and hypoxia and decreasing with diets rich in Trp, 3X TRP and 4X TRP. A higher increase was observed in haematocrit, plasma glucose and lactate in hypoxia than the handling groups. Our results indicate that Trp supplementation modulated cortisol response and mediated negative feedback of 5‐HT system in telencephalon after acute stress.     

Detection of minimal residual cells carrying the t(14;18) by DNA sequence amplification

By means of the polymerase chain reaction (PCR) technique, DNA sequences were amplified that flank the crossover sites of a characteristic chromosomal translocation for follicular lymphomas, t(14;18)(q32;q21). This technique permitted the detection of cells carrying the t(14;18) hybrid DNA sequences at a dilution of 1:100,000. The remission marrow and blood samples of a patient with follicular lymphoma and the t(14;18) failed to show any abnormality by morphological examination and conventional Southern blot analysis. However, the t(14;18) hybrid DNA sequences were detected by the PCR technique. Thus, this technique is a highly sensitive tool to detect minimal residual cells carrying the t(14;18) and has the potential to identify a subpopulation of patients with subclinical disease.