Can the polyculture with South American catfish improve the feeding efficiency of rainbow trout culture?

The objective of this study was to determine if the South American catfish (Rhamdia quelen) is suitable to be farmed in polyculture with rainbow trout (Oncorhynchus mykiss) in intensive systems during the juvenile phase to maximize feed efficiency. Juveniles of rainbow trout (3.94?±?0.11 g) and South American catfish (2.07?±?0.04 g) were distributed in 16 tanks (100 L) with continuous water renewal at the density of 50 fish/tank. The experimental design was completely randomized with four treatments (proportions between species) and four replicates. The treatments were 100% trout (100T), 70% trout and 30% catfish (70T30C), 50% trout and 50% catfish (50T50C), and 100% catfish (100C). Fish were fed twice daily with pelleted commercial feed (45% crude protein) during an experimental period of 56 days. No feed was provided for the catfish in polyculture. The weight gained by the trout was higher in polyculture. Fish survival did not differ among the treatments. The average survival of the trout in all tanks was 99.6?±?1.0%, while the survival of the South American catfish was 97.9?±?2.7%. The total feed conversion ratio was lower in the 70T30J treatment, followed by the 100T treatment. Rainbow trout and South American catfish are compatible species for farming together in the first phase of their juvenile development. The different spaces occupied by these species inside tanks probably prevent competition or agonistic behavior. Catfish eat the non-ingested leftover diet from the trout, which improves feed conversion and increases sustainability.     

Development of a Core Collection Based on EST-SSR Markers and Phenotypic Traits in Foxtail Millet [Setaria italica (L.) P. Beauv.]

Journal of Crop Science and Biotechnology - The germplasm resources of foxtail millet reserve diverse genes for crop improvement which needs to be explored. To comprehend the maximum genetic...     

黄土高原高糖黑麦草的产量和品质预测

为探明黄土高原高糖黑麦草(Lolium perenne)粗蛋白、粗脂肪、中性洗涤纤维、酸性洗涤纤维、粗灰分、可溶性碳水化合物等指标及产草量与其生长时间、株高、分蘖之间的关系,本研究采用田间试验结合预测模型的方法,利用生长时间、株高、分蘖对高糖黑麦草在模拟轮牧和收获干草两种利用方式下的牧草产量及品质进行预测。结果表明,收获干草的Aberavon、Aberstar、Premium和Abermagic黑麦草生长时间、株高和分蘖均与各营养指标显著相关(P0.05);模拟轮牧的Aberavon、Aberstar、Premium和Abermagic黑麦草株高与各营养指标均不相关(P0.05),生长时间、分蘖与粗蛋白、粗灰分之外的其它品质指标均显著相关(P0.05)。利用生长时间、株高、分蘖对4个黑麦草品种的产草量和饲用成分建立一元回归预测和多元回归预测模型,经预测值与实测值对比,预测结果准确度均较高,可为高糖黑麦草在黄土高原栽培和利用提供科学依据。     

Effect of elevated nitrogen levels on endogenous gibberellin and jasmonic acid contents of three rice (Oryza sativa L.) cultivars

Three rice (Oryza sativa L.) cultivars ( cv. Daesanbyeo, cv. Dongjinbyeo, cv. Junambyeo) were analyzed for endogenous gibberellin (GA) and jasmonic acid (JA) contents and their changes in response to elevated nitrogen (N) levels. The N fertilizer was applied in the form of urea [(NH₂)₂CO] at three rates (0, 36.8, 73.6 kg N ha^–1). Plant growth (height and dry weight) was enhanced by the first N rate but not further enhanced by the highest rate. The endogenous GA contents were analyzed through high‐performance liquid chromatography (HPLC) and gas chromatography–mass spectrometry–selected ion monitoring (GC‐MS‐SIM) while that of JA with GC‐MS‐SIM. They were analyzed one week after N application and were significantly increased with elevated N levels in all rice cultivars. The bioactive GA₁ markedly increased, but its concentration differed in different rice cultivars. Similar fluctuations were observed for endogenous GA₈, GA₁₂, GA₁₉, GA₂₀, and GA₅₃ in response to elevated N levels, showing that the rates of biosynthesis of GAs were differently affected by elevated N levels within different rice cultivars. The level of GA₂₀, a precursor of GA₁ biosynthesis, was not significantly increased, though GA₁₉, a precursor of GA₂₀, was found to be the most abundant GA type in all rice cultivars. Jasmonic acid content in the plants increased with the basic urea application (36.8 kg N ha^–1), but significantly decreased with the double urea level (73.6 kg N ha^–1). The results demonstrate that GA and JA are differentially affected in response to elevated N application in rice.     

3-Methylthiopropionic acid ethyl ester, isolated from Katsura-uri (Japanese pickling melon, Cucumis melo var. conomon), enhanced differentiation in human colon cancer cells

The fully ripened fruit of Katsura-uri Japanese pickling melon ( Cucumis melo var. conomon) has rarely been used for food because the midripened fruit is utilized for making pickles, but the fully ripened fruit is no longer valuable for pickles due to the fruit body being too soft. We have considered the utilization of the fully ripened Katsura-uri fruit that may be used for nonpickling products, particularly if the fully ripened fruit demonstrated health benefits such as anticarcinogenic properties. The phytochemical extract from the fully ripened fruit of Katsura-uri Japanese pickling melon was purified via a bioassay-guided fractionation scheme, which was based on the induction of differentiation in a RCM-1 human colon cancer cell line. On the criteria of two differentiation markers (duct formation and alkaline phosphatase activity), the most potent fraction contained a compound identified as 3-methylthiopropionic acid ethyl ester, based on GC retention time, EI-MS, (1)H NMR, and (13)C NMR spectra. Previously, the role of 3-methylthiopropionic acid ethyl ester was considered as an odor producing compound in many fruits, but this study indicates potential medical benefits of this compound.     

Sorption of Pb in chemical and particle-size fractions of soils with different physico-chemical properties

Journal of Soils and Sediments - Lead (Pb) sorption capacity (PbSmax) and distribution in chemical and particle-size fractions of six soils with different physico-chemical properties were...     

In silico-selection of Brassica rapa organelle genome-derived BACs using their end sequences and sequence level comparative analysis of the 124 kb mitochondrial genome sequences in the family Brassicaceae

We identified BAC clones which harbor DNAs derived from the B. rapa organelle genomes by in silico mapping of 80,292 B. rapa BAC end sequences on the Arabidopsis organelle genomes and subsequent insert size estimation and fingerprinting. A total of 1,048 putative chloroplast genome-derived BAC clones (2.6%) were identified. Fingerprinting and sequencing revealed that many of them represented the entire chloroplast genome (about 150 kb). Meanwhile, only 59 putative mitochondrial genome-derived BACs (0.15%) were identified and most of them showed rare agreement between the in silico map and fingerprinting. We sequenced BAC clone KBrB042G11 (42G11) and compared it to the mitochondrial genome of B. napus and A. thaliana which showed dynamic rearrangement events. The order of 33 orthologous genes was collinear between the 42G11 BAC and its counterpart in B. napus. Five distinctive rearrangements and two InDels were identified between these two closely related species and the rearrangements were related to the occurrence of small tandem repeat sequences. Sequences of the 33 orthologous genes in the homoeologous regions of B. napus and B. rapa were almost 100% identical. Gene orders showed no colinearity between Arabidopsis and Brassica even though 31 orthologous genes shared high sequence similarity with p-values over 1E-32. FISH analysis using the identified BAC revealed a large chloroplast genome insertion in the pericentromeric region of chromosome (chr.) 4 of B. rapa.