Nematode infection in fish from Cartagena Bay, North of Colombia

Parasitic nematode infection indices were recorded in different fish species collected at Cartagena Bay, North of Colombia. Among 19 studied species, the Mugil genus presented the highest prevalence (83.9-100%), although Sciades herzbergii, Caranx hippos and Centropomus undecimalis were also found infected with nematodes. Parasites were found in the liver, intestinal mesenteries and encysted near the intervertebral joints, with an average parasite abundance of 4.0 ± 0.3 nematodes per fish. Morphological analysis allowed the identification of these nematodes as Contracaecum sp. A small, but positive correlation was found between parasite abundance and length (R=0.294, P<0.001) and weight (R=0.244, P<0.001). In contrast, the correlation between parasite abundance and condition factor was negative (R=-0.191, P<0.001). These results are the first describing the presence of nematodes in several fish species of this ecosystem, and it highlights the need for monitoring parasitism in Mugil species in order to avoid parasite ingestion during fish consumption.     

Effect of simulated gastrointestinal digestion on sialic acid and gangliosides present in human milk and infant formulas

The effects of simulated gastrointestinal digestion upon sialic acid and gangliosides in infant and follow-on formulas and human milk, as well as their bioaccessibility, have been evaluated. The gastric stage is the step that causes a greater decrease in sialic acid and ganglioside contents. The intestinal stage only decreases the total and individual contents of gangliosides. After gastrointestinal digestion, neither sialic acid nor gangliosides were found in the nonbioaccessible fraction. The highest bioaccessibility (100 × content in soluble fraction after gastrointestinal digestion/total content) of sialic acid is found in human milk (87%), followed by infant formula (77%) and follow-on formula (16%). In the case of gangliosides, the highest bioaccessibility is present in the follow-on formula (51%), followed by human milk (29%) and infant formula (5%).     

Repellent activity of essential oils and some of their individual constituents against Tribolium castaneum herbst

A tool for integrated pest management is the use of essential oils (EOs) and plant extracts. In this study, EOs from Tagetes lucida , Lepechinia betonicifolia , Lippia alba , Cananga odorata , and Rosmarinus officinalis , species grown in Colombia, were analyzed by gas chromatography-mass spectrometry. These oils as well as several of their constituents were tested for repellent activity against Tribolium castaneum , using the area preference method. The main components (>10%) found in EOs were methylchavicol, limonene/α-pinene, carvone/limonene, benzyl acetate/linalool/benzyl benzoate, and α-pinene, for T. lucida, L. betonicifolia, L. alba, C. odorata, and R. officinalis, respectively. All EOs were repellent, followed a dose-response relationship, and had bioactivity similar to or better than that of commercial compound IR3535. EOs from C. odorata and L. alba were the most active. Compounds from EOs, such benzyl benzoate, β-myrcene, and carvone, showed good repellent properties. In short, EOs from plants cultivated in Colombia are sources of repellents against T. castaneum.     

Stability of plant sterols in ingredients used in functional foods

The content of plant sterol (PS) and their oxidation products (POPs) in eight ingredients used to enrich functional foods was studied. A gas chromatographic (GC) technique with mass-spectrometric detection was used for identification, while GC with a flame ionization detector (GC-FID) was used for quantification. β-Sitosterol was the most abundant phytosterol, and the main POPs found were derived from this compound (7α/β-hydroxysitosterol, 7-ketositosterol, and sitostanetriol). The total amount of POPs found in the ingredients ranged from 29.03 to 110.02 μg/100 g PS. The β-sitosterol oxidation rates ranged from 10 to 50 μg β-sitosterol oxides/100 g of β-sitosterol. In view of this low rate of oxidation in the ingredients tested, it can be concluded that the PS remain stable in these ingredients. Significant correlations (p < 0.01) were found between total oxysitosterols versus β-sitosterol contents (R(2) = 86.5%) and between total POPs and total PS (R(2) = 81.6%).     

Hyperoxygenation and bottle storage of Chardonnay white wines: effects on color-related phenolics, volatile composition, and sensory characteristics

The effects of hyperoxygenation on Chardonnay white musts and the influence of subsequent storage on the corresponding wines have been evaluated. Attention was focused on the color characteristics, phenolic and volatile composition, and sensorial analysis, not previously reported in conjunction. On the one hand, the hyperoxygenation treatment provoked a significant decrease in the concentration of virtually all phenolic compounds in musts, young wines, and one-year-stored wines. In addition, a higher resistance to browning was observed in stored wines derived from hyperoxygenated musts. Different storage conditions (light and dark) produced significant differences in the 2-S-glutathionylcaftaric acid derivatives amounts. On the other hand, significant differences were observed in the volatile composition of wines due to the hyperoxygenation treatment, such as a decrease in the isoamylic alcohols concentration, acetaldehyde, and β-damascenone, even after storage under different conditions. Finally, Chardonnay white wines derived from hyperoxygenated musts had higher banana odor and lower herbaceous and flowery notes.     

Sequential Elution Technique in Moss Pseudoscleropodium purum: Comparison between the Commonly Used Extracellular Extractant NiCl2 and Other New Extractants

The sequential elution technique (SET) is used to determine the distribution of elements in the different cell fractions of mosses. The extracellular extractants most commonly used in this technique are NiCl₂ and EDTA, although there are certain disadvantages associated with their use. In order to avoid such problems, we searched for new extractants that displace extracellularly bound metals, either because they are present at high concentrations (Ca) or because they have a high affinity for cation exchange sites (Hg and Au). The compounds HCl, NaCl, and CaCl₂ were tested as extractants of the former type, as possible alternatives for the determination of extracellular metals in the moss Pseudoscleropodium purum. Calcium chloride was finally chosen as is it potentially the most successful in terms of binding to the cation exchange sites without altering the membrane permeability. The concentration chosen was 160 mM, as this yielded maximum displacement of Zn without membrane alterations. An experiment was then carried out to test the efficiency of Ca in extracting extracellular Zn, under laboratory and field conditions. In addition, Hg and Au were tested, at different concentrations, as extractants with high affinity for cation exchange sites, as neither of these elements has previously been used in the SET, and both display electronic characteristics that suggest their potential usefulness in displacing other cations from cation exchange sites. The results obtained show that extraction of extracellularly bound metal by high concentrations of Ca should be ruled out, as total extraction of Zn was not achieved. Both Hg and Au produced membrane alterations at low concentrations and moreover, neither was more efficient at extracting Zn than the reference extractant (20 mM NiCl₂).     

Combined effects of prefermentative skin maceration and oxygen addition of must on color-related phenolics, volatile composition, and sensory characteristics of Airén white wine

The effects of the joint prefermentative maceration and hyperoxygenation of Airén white must and wine on the phenolic content, chromatic characteristics, volatile composition, and sensory characteristics, not previously described in combination, have been evaluated. A total of 20 phenolic and 149 volatile compounds have been identified and quantified for that purpose. As a consequence of the oxygen addition, the concentrations of hydroxycinnamic acid derivatives and flavan-3-ols decreased (above all t-GRP and (+)-catechin), leading to color stabilization, but also the concentrations of several volatile compounds with a great importance for quality aroma decreased. Prefermentative skin maceration, previously applied to the hyperoxygenation of Airén musts, provided the aforementioned color stabilization in the respective wine but also increased the content of short-chain fatty acid esters and terpenes and decreased the concentration of C(6) alcohols. That combination of prefermentative treatments (skin maceration followed by must hyperoxygenation) produced an improvement of the global impression of the final wine based on significantly better scores of tropical fruit, body, and herbaceous notes.     

Effect of triploidy on muscle cellularity and flesh quality of turbot (Scophthalmus maximus)

Production of triploid turbot is a relevant goal for the aquaculture industry due to the benefits associated with their sterility and growth. In order for a better understanding of the final quality of the species, muscle cellularity and quality parameters of the flesh were studied in seven diploid and seven triploid turbot after sexual maturation. White muscle cellularity was evaluated throughout white muscle cross‐sectional area from the epaxial left muscle section of each fish. To ascertain the flesh quality, several physico‐chemical parameters (moisture, ash, protein, total fat, fatty acids and minerals) were analysed, and textural mechanical properties (springiness, hardness, chewiness, cohesiveness, gumminess and adhesiveness) were determined objectively with a texturometer. Muscle cellularity was different between both groups, such that muscle fibre density was higher for diploid specimens (P < 0.001) and muscle fibres diameters were higher for triploids (P < 0.001). Both ploidy groups showed no significant differences in moisture, ash, protein and total fat content (P > 0.05). All textural properties analysed showed no significant differences between both ploidy groups (P > 0.05). In both ploidy groups, fibre density and fibre diameter showed no significant correlations (P > 0.05) with textural parameters such as springiness, cohesiveness, chewiness and adhesiveness. Ploidy did not affect fatty acid composition, with the exception of eicosapentaenoic acid (C_20:5ω3) which was higher in the triploid group. No significant differences (P > 0.05) existed between diploid and triploid turbot in content of all minerals analysed. According to our results, the ploidy status determines significant variations on muscle cellularity but does not influence the flesh quality of the turbot.     

Effect of light limitation on the water quality,bacterial counts and performance of Litopenaeus vannamei postlarvae reared with biofloc at low salinity

The aim of this study was to evaluate the effect of light limitation on the water quality, bacterial counts and performance of Litopenaeus vannamei postlarvae reared with biofloc at low salinity (≈9 g L^?1). Two treatments were designed: T₁ = culture with natural sunlight and T₂ = culture in darkness. After 28 days, in both treatments, the final weight of shrimp was over 0.6 g with a specific growth rate over 7.4% d^?1, and a survival rate over 70%. In both treatments, Vibrio sp. concentration presented low values (culture with natural sunlight = 0.1 to 9.9 × 10² CFU mL^?1, culture in darkness = 0.4 to 11.7 × 10² CFU mL^?1) and Bacillus sp. had high values (culture with natural sunlight = 0.7 to 66.0 × 10⁴ CFU mL^?1, culture in darkness = 0.7 to 65.8 × 10⁴ CFU mL^?1). All water quality parameters remained within the ranges suitable for shrimp culture, except for alkalinity during the first stage of the study. Although in some sampling periods some significant differences were found in bacterial counts and water quality parameters, shrimp productive performance under culture with biofloc at low salinity was not affected significantly by light limitation.