High yield and nutritional quality of rice for animal feed achieved by continuous irrigation with treated municipal wastewater

Paddy and Water Environment - Two consecutive pilot-scale experiments were conducted to investigate the potential reuse of treated municipal wastewater (TWW) as an irrigation source for cultivating...     

Influence of single-nucleotide polymorphisms in the gene encoding granule-bound starch synthase I on amylose content in Vietnamese rice cultivars

Amylose content is one of the most important factors influencing the physical and chemical properties of starch in rice. Analysis of 352 Vietnamese rice cultivars revealed a wide range of variation in apparent amylose content and the expression level of granule-bound starch synthase. On the basis of single-nucleotide polymorphisms (SNP) at the splicing donor site of the first intron and in the coding region of the granule-bound starch synthase I gene, Waxy gene, alleles can be classified into seven groups that reflect differences in apparent amylose content. The very low and low apparent amylose content levels were tightly associated with a G to T in the first intron whereas intermediate and high amylose was associated with a T genotype at SNP in exon 10. The correlation between the combination of T genotype at SNP in the first intron, C in exon 6, or C in exon 10 was predominant among low amylose rice varieties. Our analysis confirmed the existence of Wx^op allele in Vietnamese rice germplasm. The results of this study suggest that the low amylose properties of Vietnamese local rice germplasm are attributable to spontaneous mutations at exons, and not at the splicing donor site.     

Presence of chlorogenic acid during in vitro maturation protects porcine oocytes from the negative effects of heat stress

Chlorogenic acid (CGA) is known to protect oocytes from oxidative stress. Here we investigated the effects of CGA on porcine oocyte maturation under heat stress and subsequent embryonic development after parthenogenetic activation. For in vitro maturation (IVM) at 41.0°C (hyperthermic condition), supplementation of the maturation medium with 50 μM CGA significantly improved the percentage of matured oocytes and reduced the rate of apoptosis relative to oocytes matured without CGA (p < .05). CGA treatment of oocytes during IVM under hyperthermia tended to increase (p < .1) percentage of blastocyst formation after parthenogenesis and significantly increased (p < .05) the total cell number per blastocyst relative to oocytes matured without CGA. For IVM at 38.5°C (isothermic condition), CGA significantly improved the rate of blastocyst development compared with oocytes matured without CGA (p < .05), but did not affect oocyte maturation, apoptosis rate or the number of cells per embryo. Omission of all antioxidants from the IVM medium significantly reduced the rate of oocyte maturation, but the rate was restored upon addition of CGA. These results demonstrate that CGA is a potent antioxidant that protects porcine oocytes from the negative effects of heat stress, thus reducing the frequency of apoptosis and improving the quality of embryos.     

Diversity in Phenotypic Profiles in Landrace Populations of Vietnamese Rice: A Case Study of Agronomic Characters for Conserving Crop Genetic Diversity on Farm

Phenotypic variation of agronomic characters in aromatic rice (Oryza sativa L.) was analyzed in order to elucidate the genetic diversity of the populations of rice landraces. Thirteen populations in Namdinh province, in the Red River Delta of Vietnam, were studied in both of farmers fields and an experimental field. Only small differences were found in agronomic characters among the populations, including populations containing different varieties. Variations among the populations in the frequency distributions of several characters suggested different degrees of diversity among the populations even among populations with the same variety name. The phenotypic profiles of farmers fields were different from those in an experimental field suggesting the environmental differences between them. One variety cultivated in the Myloc district had different phenotypic characters from the other varieties in the Haihau district more clearly in the experimental field. Since the small phenotypic variation in each of farm might be due to the genetic drift and selection by the farmers, on farm conservation of the landraces of rice is considered to be under a force to decrease phenotypic diversity. The present study suggests that the targeting several farms with different phenotypic profiles contribute to the conservation of regional genetic diversity of the landraces of rice.     

摇臂式喷头内流道流场数值模拟

用Pro/E软件建立喷头内流道的三维实体模型,选择RNGk-ε模型在CFD软件Fluent中模拟了雨鸟30PSH型摇臂式喷头在10种入口压力和4种主喷嘴直径组合下的内流道流场,分析了喷头主副喷嘴的流量、人口压力与出口平均速度等参数的关系.研究结果表明:主喷嘴直径增大时,副喷嘴流量几乎不变;主、副喷嘴的流量分配比例由主喷嘴直径决定,与入口压力无关.入口压力增大,主喷嘴出口平均速度增大,但副喷嘴出口平均速度不变.喷头主、副喷嘴的平均湍动能随人口压力增大而增大,不受主喷嘴直径变化的影响.主喷嘴出口静压力、湍动能和速度的标准差、副喷嘴出口静压力标准差与入口压力近似成正比;而副喷嘴出口湍动能和速度的标准差随主喷嘴直径或入口压力增大产生较大的无规律变化.喷头内流道流场的可视化结果显示喷头副喷嘴与弯管连接处静压力较大,接近喷头入口静压力.     

Wet sieving versus dry crushing: Soil microaggregates reveal different physical structure,bacterial diversity and organic matter composition in a clay gradient

Soil microaggregates contain particles of different sizes, which may affect their potential to store organic carbon (OC). A variety of methods can be used to isolate microaggregates from the larger soil structures, among which wet sieving approaches are widely employed. We developed a novel dry crushing method that isolates microaggregates along failure planes due to mechanical stresses rather than hydraulic pressures and compared the mechanical stability, OC contents and microbial community composition between dry-crushed and wet-sieved samples with contrasting clay contents. Dry-crushed samples exhibited a higher stability and bacterial diversity compared to wet-sieved samples. As a result, the dry-crushed microaggregates had different size distributions when analysed dry and after wetting. In the dry state, dry-crushed microaggregates were larger and contained more sand-sized primary particles within the aggregate structures. The wetting of dry-crushed aggregates caused a disintegration of larger microaggregates and sand-sized primary particles into smaller microaggregates that contained finer particles. In the soils with lower clay contents, the diameter of dry-crushed microaggregates was 40 μm larger due to more sand-sized primary particles remaining within the aggregates. Depending on how much volume in microaggregates is occupied by large primary particles, the OC concentration increased in the soil with higher clay content. Wet-sieved size fractions also showed a similar pattern of OC distribution, whereas more primary particles were observed outside of aggregates. Wet sieving approaches disperse the soil into OC-rich aggregates and might be preferable if OC dynamics are investigated. Differences in bacterial community composition in dependence on clay content were more pronounced in dry-crushed microaggregates. If intact aggregate architectures are of interest for the isolation of soil structural units, the presented dry crushing method might provide an advantageous alternative that also better preserves bacterial diversity.     

Improved techniques for rearing mud crab Scylla paramamosain (Estampador 1949) larvae

A series of rearing trials in small 1 L cones and large tanks of 30–100 L were carried out to develop optimal rearing techniques for mud crab (Scylla paramamosain) larvae. Using water exchange (discontinuous partial water renewal or continuous treatment through biofiltration) and micro‐algae (Chlorella or Chaetoceros) supplementation (daily supplementation at 0.1–0.2 million cells mL⁻¹ or maintenance at 1–2 millions cells mL⁻¹), six different types of rearing systems were tried. The combination of a green‐water batch system for early stages and a recirculating system with micro‐algae supplementation for later stages resulted in the best overall performance of the crab larvae. No clear effects of crab stocking density (50–200 larvae L⁻¹) and rotifer (30–60 rotifers mL⁻¹) and Artemia density (10–20 L⁻¹) were observed. A stocking density of 100–150 zoea 1 (Z1) L⁻¹, combined with rotifer of 30–45 mL⁻¹ for early stages and Artemia feeding at 10–15 nauplii mL⁻¹ for Z3–Z5 seemed to produce the best performance of S. paramamosain larvae. Optimal rations for crab larvae should, however, be adjusted depending on the species, larval stage, larval status, prey size, rearing system and techniques. A practical feeding schedule could be to increase live food density from 30 to 45 rotifers mL⁻¹ from Z1 to Z2 and increase the number of Artemia nauplii mL⁻¹ from 10 to 15 from Z3 to Z5. Bacterial disease remains one of the key factors underlying the high mortality in the zoea stages. Further research to develop safe prophylactic treatments is therefore warranted. Combined with proper live food enrichment techniques, application of these findings has sustained a survival rate from Z1 to crab 1–2 stages in large rearing tanks of 10–15% (maximum 30%).     

Epigenetic modulation on cat‐cow interspecies somatic cell nuclear transfer embryos by treatment with trichostatin A

This study aimed to determine the acetylation at lysine 9/18/23 of histone H3 (H3K9ac/H3K18ac/H3K23ac; H3K9/18/23 ac) and the di‐methylation at lysine 9 of histone H3 (H3K9me2) during early embryogenesis among trichostatin A (TSA)‐treated interspecies somatic cell nuclear transfer (iSCNT) cat‐cow (TSA‐iSCNT) embryos, TSA‐untreated iSCNT cat‐cow control (control) embryos and bovine in vitro fertilization (IVF) embryos, because TSA‐iSCNT embryos can develop to blastocysts. Compared to the control embryos, higher expressions of H3K9/18/23 ac were observed in TSA‐iSCNT embryos and IVF embryos at most following stages (2 h post‐fusion / post‐insemination (PF/PI) to eight‐cell stage). At 6 h PF/PI the expression of H3K9/23 ac in TSA‐iSCNT embryos and IVF embryos were lower than those in control embryos, and the expression of H3K18ac was no difference among the three groups. The expression of H3K9/23 ac increased in TSA‐iSCNT embryos and IVF embryos at pronuclear (PN) stages. The expression of H3K9me2 in TSA‐iSCNT embryos resembled that of IVF embryos at 2 h PF/PI to PN stages, and these expression levels were greater than those of control embryos. These results suggest that treatment of iSCNT embryos with TSA modifies the patterns of histone modification at certain lysine residues in a manner that is comparable with that seen in IVF during early embryogenesis.     

Effects of chlorogenic acid (CGA) supplementation during in vitro maturation culture on the development and quality of porcine embryos with electroporation treatment after in vitro fertilization

Electroporation is the technique of choice to introduce an exogenous gene into embryos for transgenic animal production. Although this technique is practical and effective, embryonic damage caused by electroporation treatment remains a major problem. This study was conducted to evaluate the optimal culture system for electroporation‐treated porcine embryos by supplementation of chlorogenic acid (CGA), a potent antioxidant, during in vitro oocyte maturation. The oocytes were treated with various concentrations of CGA (0, 10, 50, and 100 μmol/L) through the duration of maturation for 44 hr. The treated oocytes were then fertilized, electroporated at 30 V/mm with five 1 msec unipolar pulses, and subsequently cultured in vitro until development into the blastocyst stage. Without electroporation, the treatment with 50 μmol/L CGA had useful effects on the maturation rate of oocytes, the total cell number, and the apoptotic nucleus indices of blastocysts. When the oocytes were electroporated after in vitro fertilization, the treatment with 50 μmol/L CGA supplementation significantly improved the rate of oocytes that developed into blastocysts and reduced the apoptotic nucleus indices (4.7% and 7.6, respectively) compared with those of the untreated group (1.4% and 13.0, respectively). These results suggested that supplementation with 50 μmol/L CGA during maturation improves porcine embryonic development and quality of electroporation‐treated embryos.     

In vitro development of OPU‐derived bovine embryos cultured either individually or in groups with the silk protein sericin and the viability of frozen‐thawed embryos after transfer

The optimization of single‐embryo culture conditions is very important, particularly in the in vitro production of bovine embryos using the ovum pick‐up (OPU) procedure. The purpose of this study was to examine the development of embryos derived from oocytes obtained by OPU that were cultured either individually or in groups in medium supplemented with or without sericin and to investigate the viability of the frozen‐thawed embryos after a direct transfer. When two‐cell‐stage embryos were cultured either individually or in groups for 7 days in CR1aa medium supplemented with or without 0.5% sericin, the rates of development to blastocysts and freezable blastocysts were significantly lower for the embryos cultured individually without sericin than for the embryos cultured in groups with or without sericin. Moreover, the rate of development to freezable blastocysts of the embryos cultured individually with sericin was significantly higher than that of the embryos cultured without sericin. When the frozen‐thawed embryos were transferred directly to recipients, the rates of pregnancy, abortion, stillbirth and normal calving in the recipients were similar among the groups, irrespective of the culture conditions and sericin supplementation. Our findings indicate that supplementation with sericin during embryo culture improves the quality of the embryos cultured individually but not the viability of the frozen‐thawed embryos after transfer to recipients.