Dietary monosodium glutamate supplementation during the feed training of pacamã (Lophiosilurus alexandri): Growth performance and intestinal histomorphometry

Feed training of carnivorous fish is a delicate and stressful process. Thus, feed additives that reduce stress and encourage fish consumption could improve training efficiency. Therefore, the aim of this study was to evaluate monosodium glutamate (MSG) dietary supplementation during pacamã (Lophiosilurus alexandri) feed training through growth performance and intestinal histomorphometry. Fish were trained by the method of gradual diet transition, using five diets with increasing proportions of commercial diet and decreasing proportions of gelatin. A quadruplicate experimental design was performed with seven treatments, consisted in diets supplemented with different levels of MSG (0.0; 2.0; 8.0; 16.0; 29.0; 34.0 and 42.0 g/kg). Pacamã (0.17 ± 0.01 g) were distributed in 28 tanks (30 fish per tank) and trained for 41 days with the experimental diets. There were no effects (p > .05) of MSG on growth performance and feed training indices. However, fish trained with diets supplemented with 42.0 g/kg of MSG presented higher number of goblet cells in the anterior portion of intestine (p < .05). These results demonstrate that MSG did not act on growth performance and feed training efficiency of pacamã, and high levels of MSG can cause dietary stress on fish intestinal mucosa.     

草本水杨梅的研究进展

草本水杨梅为多年生草本植物,资源丰富。草本水杨梅中含有黄酮、苯丙素、鞣质、挥发油、氨基酸和无机元素等多种化学成分,并具有抗病毒、抗炎、抗凝血及抗自由基等药理作用。本文对其化学成分和药理作用的研究进展进行综述。     

Analysis of the genetic control of β-carotene and <Emphasis Type="SmallCaps">l</Emphasis>-ascorbic acid accumulation in an orange-brownish wild cherry tomato accession

An additive-dominance, additive × additive (ADAA) and genotype × environment interaction mix model was used to study the genetic control of β-carotene and l-ascorbic acid in six basic generations (P₁, P₂, F₁, F₂, BC₁P₁ and BC₁P₂) of tomato derived from the cross CDP8779 accession (Solanum lycopersicum L.) × CDP4777 accession (S. lycopersicum var. cerasiforme). The study was performed in two environments: (1) open field; (2) protected environment, consisting of hydroponic cultivation in a glasshouse. The results indicate that β-carotene accumulation was mainly additive (32.2% of the genetic component), with a small dominant component (4.2%) and an important additive × environment interaction contribution (63.6%). In target environments with moderate to high temperatures and no limiting radiation, this the expression additive × environment interaction could substantially enhance the β-carotene content. This trait showed also a high narrow-sense heritability (h ² = 0.62). Ascorbic acid accumulation was also mainly additive (61.7% of the genetic component), with a minor additive epistatic component (21.5%). This epistatic effect caused a negative heterosis that reduced the positive main additive effect. Nevertheless, in the described target environments, the additive × environment interaction contribution (16.8%) may enhance the ascorbic acid content and compensate for the negative heterosis effect. The total narrow-sense heritability of this trait can be considered useful (h ² = 0.52). In conclusion, the CDP4777 accession is a very interesting donor parent for the joint improvement of β-carotene (without diminishing lycopene content) and ascorbic acid content in commercial nutraceutical tomato breeding programmes; the F₁ hybrids derived from this accession showed nearly 450% of the commonly reported average β-carotene content and close to 130% of the ascorbic acid content of the female parent.     

Confirmation and characterization of interspecific hybrids of <Emphasis Type="Italic">Passiflora</Emphasis> L. (Passifloraceae) for ornamental use

Three new varieties of Passiflora hybrids were developed from crosses between P. sublanceolata J. M. MacDougal (ex P. palmeri var. sublanceolata Killip) versus P. foetida var. foetida L. Twenty putative hybrids were analyzed. Hybridizations were confirmed by RAPD and SSR markers. The RAPD primer UBC11 (5′-CCGGCCTTAC-3′) generated informative bands. The SSR primer A08FP1 amplified species-specific fragments and heterozygote status was observed with the two parent bands 240 and 280 bp. The molecular markers generated by primers were analyzed in terms of the presence or absence of specific informative bands. The morphological characterization of the hybrids enabled their differentiation into three groups, identified as: (1) Passiflora ‘Alva’, composed of five hybrid plants with white flowers, large corona, light purple filaments at base, white and purple/white banding to apex; (2) P. ‘Aninha’, composed of six hybrid plants with pale pink flowers, corona filaments reddish/purple at base, white, purple/white banding to apex; (3) P. ‘Priscilla’, composed of nine hybrid plants with white flowers, small corona, filaments dark purple at base, white and purple to apex. The genomic homology of parent plants was verified by cytogenetic analysis. Both parents were 2n = 22. Meiosis was regular in genitors and hybrids. Aneuploidy was observed at hybrid groups P. ‘Alva’ and P. ‘Priscilla’ (2n = 20). Other authors had already observed the same number of chromosomes for some P. foetida genotypes. Obtaining valuable interspecific hybrids opens up new perspectives to offer opportunities in agribusiness for producers and to arouse the interest of consumers into using passion flowers in the Brazilian ornamental plant market.     

Comparative effect of low temperature on virulence and twitching motility of Ralstonia solanacearum strains present in Florida

Ralstonia solanacearum causes bacterial wilt on a wide range of plant hosts. Most strains of R. solanacearum are nonpathogenic below 20°C; however, Race 3 Biovar 2 (R3B2) strains are classified as quarantine pathogens because of their ability to infect crops, cause disease, and survive in temperate climates. We have identified race 1 biovar 1 Phylotype IIB Sequevar 4 strains present in Florida which were able to infect and produce wilt symptoms on potato and tomato at 18°C. Moreover they infected tomato plants at rates similar to strains belonging to R3B2. We determined that strains naturally nonpathogenic at 18°C were able to multiply, move in planta, and cause partial wilt when inoculated directly into the stem, suggesting that low temperature affects virulence of strains differently at early stages of infection. Bacterial growth in vitro was delayed at low temperatures, however it was not attenuated. Twitching motility observed on growing colonies was attenuated in nonpathogenic strains at 18°C, while not affected in the cool virulent ones. Using pilQ as a marker to evaluate the relative expression of the twitching activity of R. solanacearum strains, we confirmed that cool virulent strains maintained a similar level of pilQ expression at both temperatures, while in nonpathogenic strains pilQ was downregulated at 18°C.     

The potential for respiratory droplet-transmissible A/H5N1 influenza virus to evolve in a mammalian host

Avian A/H5N1 influenza viruses pose a pandemic threat. As few as five amino acid substitutions, or four with reassortment, might be sufficient for mammal-to-mammal transmission through respiratory droplets. From surveillance data, we found that two of these substitutions are common in A/H5N1 viruses, and thus, some viruses might require only three additional substitutions to become transmissible via respiratory droplets between mammals. We used a mathematical model of within-host virus evolution to study factors that could increase and decrease the probability of the remaining substitutions evolving after the virus has infected a mammalian host. These factors, combined with the presence of some of these substitutions in circulating strains, make a virus evolving in nature a potentially serious threat. These results highlight critical areas in which more data are needed for assessing, and potentially averting, this threat.     

Influence of industrial and alternative farming systems on contents of sugars, organic acids, total phenolic content, and the antioxidant activity of red beet (Beta vulgaris L. ssp. vulgaris Rote Kugel)

The contents of sugars, organic acids, total phenolic content, and the antioxidant activity were quantified in the flesh of red beet from conventional (CON), integrated (INT), organic (ORG), biodynamic (BD), and control farming systems using established methods. Significant differences were measured for malic acid, total phenolic content (TPC), and total antioxidant activity, where malic acid content ranged from 2.39 g kg(-1) FW (control) to 1.63 g kg(-1) FW (CON, ORG, and INT). The highest TPC was measured in BD and control samples (0.677 and 0.672 mg GAE g(-1), respectively), and the lowest in CON samples (0.511 mg GAE g(-1)). Antioxidant activity was positively correlated with TPC (r2=0.6187) and ranged from 0.823 μM TE g(-1) FW to 1.270 μM TE g(-1) FW in CON and BD samples, respectively, whereas total sugar content ranged from 21.03 g kg(-1) FW (CON) to 31.58 g kg(-1) FW (BD). The importance of sugars, organic acids, phenols, and antioxidants for human health, as well as for plant resilience and health, gained from this explorative study, is discussed and put into perspective.     

Conjugates of bovine serum albumin with chitin oligosaccharides prepared through the Maillard reaction

Chitin neoglycoconjugates (BSA-CO) were obtained by the conjugation of bovine serum albumin (BSA) with chitin oligosaccharides (CO) through the Maillard reaction (nonenzymatic glycation). CO produced by acid hydrolysis of chitin were fractionated using an ultrafiltration membrane system (1-3 kDa cutoff). The Maillard reaction was carried out by heating a freeze-dried mixture containing BSA and CO at 60 °C (under 43% relative humidity for 6 and 12 h). BSA-CO were characterized by available amino groups content, intrinsic tryptophan emission spectra, gel electrophoresis, and mass spectrometry. Biological assays included interaction with wheat germ agglutinin (WGA) and with bacterial adhesins of Escherichia coli K88+ and Salmonella choleraesuis. Glycation of BSA was revealed by reduction of available amino groups and fluorescence intensity and also retarded migration through SDS-PAGE. Conjugation of BSA with chitin oligomers appeared to be time dependent and was confirmed by mass spectrometry, by which molecular mass increase for monomers and dimers was observed. Monomers were estimated to contain either one or two glycation sites (at 6 and 12 h of treatment, respectively), with one or two tetrasaccharide units attached. Consequently, dimers showed two or four glycation sites. BSA-CO presented biological recognition by WGA and E. coli K88+ and S. cholerasuis adhesins. The strategy used in this work represents a simple method to obtain glycoconjugates to study applications involving protein-carbohydrate recognition.     

Comparison of Artificial and Natural, New and Reused, Brackish Water for the Larviculture of the Freshwater Prawn Macrobrachiurn rosenbergii in a Recirculating System

Abstract— Differences in culture duration, metamorphosis rate and the productivity in hatchery culture of M. rosenbergii using a closed system with natural and artificial brackish water were evaluated. Reuse of brackish water in more than one hatchery cycle was also evaluated. Natural and artificial brackish water constituted the two tested treatments, which were distributed in four independent recirculating systems (tank and respective biofilter). Four batches of cultures were conducted and the 2nd and 4th reused the water from the 1st and 3rd. respectively. Mean duration of the hatchery period was 28 d in natural brackish water and 31 d in artificial brackish water. The metamorphosis rate and the average productivity for the natural brackish water treatment were 74% and 60 postlarvael l, respectively, and values obtained with artificial brackish water were 55% and 44 postlarvae/L. The successful hatchery culture of M. rosenbergii in this specific artificial brackish water suggests its potential use in enterprises located far from the coast. Brackish water can be used in two consecutive cultures without a negative effect on productivity.     

Effect of the protein/energy ratio on the growth of Mediterranean yellowtail (Seriola dumerili)

Yellowtails weighing 490 g were fed five experimental diets with different protein/energy ratios, 24.6, 26.9, 28.9, 31.8 and 35.8 g MJ⁻¹, for 152 days. The energy content was similar in all the diets and the protein and lipid levels were 40/26, 45/26, 50/18, 50/26 and 55/18 %CP/%CL respectively. The final weight and SGR were lower in fish fed diets with a lower PD/ED ratio (24.6 and 26.9 g MJ⁻¹), and the mortality of fish fed diet 24.6 g MJ⁻¹ was higher. In fact, only fish that consumed diet 35.8 g MJ⁻¹ had a haematocrit and a normal erythrocyte number similar to that in healthy yellowtail. No differences appeared in feed intake and feed conversion ratio. Digestible energy ingestion was similar for all the diets and digestible protein intake was also low for 24.6 compared with 35.8 g MJ⁻¹. The meat composition was similar for fish fed all the diets, but the profiles of muscle fatty acids indicated an increasing content of saturates and n-3 HUFA, while the levels of monounsaturates decreased, corresponding to an increase in the PD/ED relation. The economic conversion ratio and economic profit index were not different for fish fed the experimental diets.