Debaryomyces hansenii L2‐enriched diet enhances the immunity status,gene expression and intestine functionality in gilthead seabream (Sparus aurata L.)

This study evaluates the effects of the dietary administration of the live yeast Debaryomyces hansenii strain L2 on the immune responses of gilthead seabream for 4 weeks. Cellular immune parameters were measured from serum and head‐kidney leucocytes respectively. The expression levels of immune‐associated genes were quantified by real‐time polymerase chain reaction. In addition, the profile of intestinal microbiota was studied by denaturing gradient gel electrophoresis. The results showed that seabream fed a diet containing D. hansenii had significantly increased cellular immune parameters. The yeast‐supplemented diet up‐regulated the expression of most seabream genes at week 2 and down‐regulated all of them at week 4, except in the head‐kidney. Finally, a reduction in the diversity of the intestinal microbiota was detected in those specimens receiving the yeast‐supplemented diet. These results support the idea that the live yeast D. hansenii strain L2 stimulates the immune system of gilthead seabream.     

Live-weight gains of Holstein × Zebu heifers grazing a <Emphasis Type="Italic">Cratylia argentea</Emphasis>/Toledo-grass (<Emphasis Type="Italic">Brachiaria brizantha</Emphasis>) association in the Mexican humid tropics

The legume Cratylia argentea associated to Brachiaria brizantha—Toledo-grass (Bb + Ca) and Toledo-grass alone (Bb) were evaluated under grazing conditions by Holstein × Zebu heifers. Three evaluation periods during three consecutive years, were performed. We measured, daily live-weight gains of heifers (DWG, g/day); biomass dry matter (BDM, kg/ha) at beginning and end of each grazing period. On plant samples, were measured percentages of crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, in situ DM degradability (ISDMD), and voluntary biomass DM intake (VBI, g/LW^0.75) using the Cr₂O₃/in situ indigestibility technique. A completely randomized design was applied, using heifers as experimental units for DWG gains and VBI. At the beginning of the grazing, the BDM for Bb + Ca and Bb–considering the three periods-averaged, 3065 and 936 kg/ha, respectively. Crude protein content of C. argentea was around 20 %; and for Bb + Ca or Bb, ranged from 8.7 to 4.6 %. In either treatment, in situ DM degradability averaged 72.6 % (P ≥ 0.05), regardless of the botanical component type. Biomass DM intake was 83.02 (Bb + Ca) and 89.22 (Bb) g/LW^0.75. The DWG gains (g/heifer) for Bb + Ca and Bb were (per period): 829 and 574 (first); 469 and 118 (second); and 534 and 508 (third). This study showed that the Bb + Ca association was better to improve the daily gain of F1 Holstein × Zebu heifers, as compared to Bb alone. Also, C. argentea associated to a low to medium-quality grass improved the nutritional value of the diet without affecting the biomass DM intake.     

Ability of plant-based surface technology to improve urban water cycle and mesoclimate

The presented study proposes a technology that could be used in developing a stormwater management strategy. The research was conducted under the hypothesis that a plant-based surface system (PBSS) can increase the capacity of sealed urban surfaces, for example, along railway tracks, to reduce runoff volume, to increase evaporation and consequently to improve the mesoclimate. To test this statement, water retention capacity, runoff–precipitation ratio, runoff delay and evapotranspiration performance were determined for different time periods (rainwater events, daily, monthly, seasonally, yearly, and throughout the entire measuring period of 18 months) by means of a measurement strategy implemented in selected urban traffic areas of Berlin, Germany, that contained railway tracks. Additionally, a computation of the air humidity improvement of an urban test location based in measurements is presented. The main elements of the tested PBSS were a 2 cm thick vegetation mat and a 20 cm thick drainage layer. The measurement strategy for the hydrological characterization included the installation and use of weighable lysimeters, rain gauges and runoff volume counters. The runoff volume determined in some summer months for the PBSS technology amounted to 9% of precipitation. The evaporation performance in these months amounted to 100% of precipitation. These results were compared with the corresponding calculated values for an asphalt surface: runoff 70–80% of precipitation and evaporation performance of 20–30% of precipitation. The study provides evidence of the positive effect of this technology on the local water balance of the treated sealed areas.     

Live Weight Estimation of Donkeys in Central México from Measurement of Thoracic Circumference

Body measurements (length from nape of neck to the withers; height to withers; length from withers to tail root; length from shoulder to tuber ischii; thoracic circumference; umbilical circumference) were taken and correlated with live weight from 160 donkeys (mean ± standard deviation = 6 ± 2.6 years old) in Central México. The age was assessed from dentition. Sex of the donkeys was also recorded. Sex was an important factor of variation (p = 0.011). Live weight was estimated using two allometric models. Model 1: Live weight = β _o × (thoracic circumference)^β1. Model 2: Live weight = β _o × (height to the withers) ^βl × (thoracic circumference) ^β2. Separate prediction equations were produced for males and females, plus one for the total sampled. The ‘best fit’ models, were those using thoracic circumference to predict the live weight. Males: live weight = 0.018576 × (thoracic circumference)^1.84107 (R ² = 0.9839). Females: live weight = 0.031255 × (thoracic circumference)^1.72888 (R ² = 0.9839). The equations derived to estimate the live weight of donkeys in Britain, Morocco and Zimbabwe were less satisfactory for use with donkeys from Central México because they overestimated the live weight.     

Root dynamics of peach trees submitted to partial rootzone drying and continuous deficit irrigation

The root dynamics of young early-season peach trees (Prunus persica L. Batsch, cv. Flordastar) were studied during one growing season. The trees were submitted to three drip irrigation treatments: T1 (control) irrigated at 100% of the estimated crop evapotranspiration (ETc) requirements, T2 (continuous deficit) irrigated at 50% ETc and T3 (partial rootzone drying, PRD, treatment), alternating irrigation from one half to the other every 2–3 weeks. Root length was measured frequently using minirhizotrons and a circular-vision scanner. Overall, root length density was reduced by ≈73% in the continuous deficit irrigated treatment and by ≈42% in the T3 treatment with respect to the well irrigated treatment. A roughly similar amount of water was applied in both deficit irrigated treatments (44 and 56% of T1, for T2 and T3, respectively), but the continuous deficit irrigation applied to both sides of the root system in T2 resulted in a greater reduction in root growth than in T3. The dynamics of the root growth were similar in the three treatments. In general, root growth declined during the fruit growth period and increased after harvest, reaching its peak in mid July. By late July, root growth had declined again, and an alternating pattern of growth between the aerial and root parts of the tree was observed. Roots were mostly located in the upper 0.55 m of soil and were particularly concentrated at 0.40–0.55 m. More than 88% of these roots were very thin, with diameters of <0.5 mm. The study looks at the impact of deficit irrigation on the phenological processes related with root growth, and will help in making decisions concerning fertigation in areas with scarce water resources where deficit irrigation strategies are considered desirable.     

Phytotoxic effect of culture filtrate from Fusarium subglutinans the causal agent of fusariose of pineapple (Ananas comosus (L.) Merr

Two pineapple varieties differing in resistance to fusariose were examined for the phytotoxic effect of Fusarium subglutinans culture filtrate. The cultivars were Perolera (more resistant to pathovars of Fusarium subglutinans) and Smooth Cayenne (more susceptible). The phytotoxic effect of culture filtrate was assessed in tissue culture pineapple plantlets (by electrolyte leakage and placing the culture filtrate on wound leaf segments) and callus (inhibition of growth). Smooth Cayenne proved to be the most sensitive cultivar in each test, whereas Perolera showed resistance to the culture filtrate and its callus grew in the presence of high concentrations of culture filtrate that were completely toxic to Smooth Cayenne. These results show that plants can display cellular resistance to the culture filtrate. This revised version was published online in August 2006 with corrections to the Cover Date.     

Essential oil of Lippia alba in the diet of Macrobrachium rosenbergii: Effects on antioxidant enzymes and growth parameters

The juveniles of Macrobrachium rosenbergii (0.060 ± 0.004 g and 2.018 ± 0.071 cm) were fed during 60 days with diets containing different doses of Lippia alba essential oil (EOLA) (0.0—control, 1.0, or 2.0 ml EOLA/kg diet; in triplicate, with 20 prawns/replicate). After the experimental period, were verified the survival, growth parameters and the antioxidant enzymes, lipid peroxidation and Na/K‐ATPase activities in hepatopancreas and gills, respectively, of the animals. There were no significant differences on survival, growth parameters and gill Na/K‐ATPase activity. However, glutathione peroxidase and glutathione‐S‐transferase activities were lower in hepatopancreas of prawns fed with 1.0 ml EOLA/kg diet compared to the control. Moreover, the activity of the enzyme superoxide dismutase was higher in hepatopancreas of prawns that received 2.0 ml EOLA/kg diet compared to those fed with 1.0 ml EOLA/kg diet. Although the addition of both EOLA doses has not improved the survival and growth parameters of M. rosenbergii, these doses contributed to decrease lipid peroxidation. Additionally, the dose of 2.0 ml EOLA/kg diet contributed for increasing the antioxidant enzymes activities in the hepatopancreas, improving antioxidant status, and therefore, it can be recommended as diet supplementation for M. rosenbergii.     

Evaluation of the growth and survival rate of the Caribbean Sea cucumber,Isostichopus badionotus (Selenka, 1867), early juveniles produced in captivity

Isostichopus badionotus is a new commercially important sea cucumber in the Caribbean that has rapidly shown signs of overexploitation. There is no information on the growth and survival rates for wild or hatchery‐produced early juveniles. Hatchery production and determination of juvenile growth rates are essential for future aquaculture efforts for this species. In this study, daily growth rate (GR), specific growth rate (SGR), weight gain (WG), survival rate (SR), and weight–length relation (WLR) were evaluated using small (0.01 g) and large (0.25 g) hatchery‐produced early juveniles under laboratory conditions. Growth was rapid compared to other cultured sea cucumber species; maximal values of SGR and WG were obtained for small juveniles (4.58%/day and 2,191%, respectively), while maximal GR and SR were obtained for large juveniles (0.29 mm/day and 99.17%, respectively). A wide range of sizes was evident at the end of each trial. The WLR of small and large juveniles fit with a negative allometric growth trend. This study highlights the potential production of I. badionotus as early juvenile stages withstand hatchery handling well and exhibit a high SR, reaching commonly released mean sizes (>0.7 g and 25 mm) after almost 3 months (120 days postfertilization).