Growth performance responses to increased tryptophan supplementation in growing barrows fed three different very low crude protein corn and soybean meal-based diets fortified with essential amino acids

Seventy-five individually fed barrows averaging 35 kg were used in a series of three experiments for 6-week growth assays (25 barrows each) to determine the effects of l -tryptophan (Trp) supplementation on growth performance and to establish the lower limits of dietary crude protein (CP) levels. Corn and soybean meal (SBM)-based diets containing 9% (Experiment 1), 10% (Experiment 2), and 11% CP (Experiment 3) fortified with deficient essential amino acids (AAs) except Trp were used as basal diets for each experiment. The experimental diets were supplemented with 0.00%, 0.02%, 0.04%, or 0.06% Trp. A 16% CP corn–SBM-based diet was set as a positive control in each experiment, and feed and water were provided ad libitum. Average daily gain and gain-to-feed ratio improved quadratically (P < 0.05) as supplemented Trp increased in the 9% and 10% CP group, although these positive effects were not observed in the 11% CP group. Because the maximum performance parameters in 9%, 10%, and 11% CP groups were not different from that of the 16% CP positive control group, the marginally reduced level of dietary CP without growth performance being affected appears to be around 9% at most. A potential reduction of nitrogen intake was clearly indicated.     

4-(Methylthio)-3-butenyl isothiocyanate, a principal antimutagen in daikon (Raphanus sativus; Japanese white radish).

The antimutagenic activity of n-hexane extracts from eight strains of daikon (Raphanus sativus; Japanese white radish) have been examined using the UV-induced mutation assay of Escherichia coli B/r WP2. A correlation was found between the potency of antimutagenicity and the amount of 4-(methylthio)-3-butenyl isothiocyanate (MTBITC) in their n-hexane extracts. Because the pure MTBITC also showed antimutagenicity, MTBITC is presumably the active antimutagen principle in n-hexane extracts of daikon. Among the eight strains of daikon studied, Aokubi, the improved common strain in Japan, contained 71.0 micromol of MTBITC in 100 g of fresh daikon. In contrast, Karami and Momoyama, which are original wild strains, contained much more MTBITC (363.5 and 168.0 micromol/100 g, respectively). In addition, phenethyl isothiocyanate was found in a lesser amount (5-33 nmol/100 g) in eight strains of daikon, and allyl isothiocyanate and benzyl isothiocyanate were not detectable in any strains (<3 nmol/100 g). The amount of total isothiocyanate in grated daikon was 7.0 times higher than that in cut daikon measured after 30 min of cooking. Through eating habits, humans might be able to consume substantial amounts of the antimutagen MTBITC from dishes using the grated form of wild strains of daikon. Therefore, it is possible to substantially increase the intake of the antimutagenic ingredient of daikon (i.e., MTBITC) by changing food preferences and preparation procedures (i.e., using the grated form of the wild strains).     

石河子垦区饲草收贮及其设备的现状与发展对策

草地及饲料是发展畜牧业的物质基础,石河子垦区是新疆生产建设兵团的主要农牧业生产基地，全垦区饲草资源丰富，具有发展畜牧业的优势条件。本文对垦区饲草资源及储量，饲草收贮设备现状进行了分析。针对存在的问题，结合垦区特点和优势，对如何合理利用饲草资源进行了探讨，并指出了饲草收获机械和加工处理设备的发展对策。     

Inhibitory effects of (-)-epigallocatechin gallate on the mutation,DNA strand cleavage,and DNA adduct formation by heterocyclic amines

Green tea is known to be a potential chemopreventive agent against cancer. In this study, we investigated the inhibitory activities of tea extracts, and in particular the polyphenolic component (-)-epigallocatechin gallate (EGCG), against heterocyclic amine-induced genotoxicity. The tea extracts displayed inhibition of 2-hydroxyamino-6-methyldipyrido[1,2-a,3',2'-d]imidazole (Glu-P-1(NHOH))-induced mutagenicity. This inhibition can be accounted for by the presence of EGCG in the extracts. The mutagenic effect of Glu-P-1(NHOH), which induces single-strand cleavage in supercoiled circular DNA under neutral conditions, was inhibited by EGCG. Using the Drosophila repair test, a test for gross DNA damage, and DNA adduct detection by (32)P-postlabeling, we showed that EGCG prevented 2-amino-3,8-dimethylimidazo[4,5-f]quinoline-induced DNA damage and adduct formation in insect DNA. EGCG was found to accelerate the degradation of Glu-P-1(NHOH) in vitro. This observation suggested that the inhibition by EGCG is associated with an accelerated degradation of metabolically activated heterocyclic amines.     

湿地公园宣教与展示设计：系统构架与技术措施

提出湿地公园宣教与展示设计系统、13种湿地公园电子媒介宣教展示、11种室内外展示框设计、12种其他宣教展示设计方法,为湿地公园宣教与展示设计提供参考。     

豌豆蛋白粉饲喂雏鸡的试验研究

用豌豆蛋白粉替代进口、国产鱼粉和饼类蛋白质饲料进行为期6周的育雏饲喂试验。经两个鸡场9360只鸡试验显示,豌豆蛋白粉是良好的蛋白质饲料。在规模生产条件下,可完全替代进口鱼粉和饼类蛋白质饲料,生产成绩与进口鱼粉接近,而且优于国产鱼粉,但差异均不显著(P>0.05),且饲料成本每百kg可降低6～13元。育雏期每只可降低饲料费0.08～0.17元(其中完全替代鱼粉组平均降低成本0.13元,育雏期平均每只鸡可降低饲料0.17元)。     

Epigenetic dynamics of imprinted X inactivation during early mouse development

The initiation of X-chromosome inactivation is thought to be tightly correlated with early differentiation events during mouse development. Here, we show that although initially active, the paternal X chromosome undergoes imprinted inactivation from the cleavage stages, well before cellular differentiation. A reversal of the inactive state, with a loss of epigenetic marks such as histone modifications and polycomb proteins, subsequently occurs in cells of the inner cell mass (ICM), which give rise to the embryo-proper in which random X inactivation is known to occur. This reveals the remarkable plasticity of the X-inactivation process during preimplantation development and underlines the importance of the ICM in global reprogramming of epigenetic marks in the early embryo.     

木薯田间机械化作业研究现状分析

针对木薯田间机械化作业的发展前景,阐述了木薯的生物学特性,木薯在种植、中耕、收获及木薯茎秆粉碎还田方面的机械化利用现状,着重介绍了几种典型的木薯种植机、中耕机、收获机和木薯茎秆粉碎还田机,对各种机械的工作方式、工作效率和适应性进行了探讨.针对我国在木薯田间机械化作业中存在的问题,提出相应的对策建议,为木薯田间机械化作业技术的发展提供参考.     

Dyeing behavior of low temperature plasma treated wool

In this paper, the effects of low temperature plasma (LTP) treatment on the dyeing properties of the wool fiber were studied. The wool fibers were treated with oxygen plasma and three types of dye that commonly used for wool dyeing, namely: (i) acid dye, (ii) chrome dye and (iii) reactive dye, were used in the dyeing process. For acid dyeing, the dyeing rate of the LTP-treated wool fiber was greatly increased but the final dyeing exhaustion equilibrium did not show any significant change. For chrome dyeing, the dyeing rate of the LTP-treated wool fiber was also increased but the final dyeing exhaustion equilibrium was only increased to a small extent. In addition, the rate of afterchroming process was similar to the chrome dyeing process. For the reactive dyeing, the dyeing rate of the LTP-treated wool fiber was greatly increased and also the final dyeing exhaustion equilibrium was increased significantly. As a result, it could conclude that the LTP treatment could improve the dyeing behavior of wool fiber in different dyeing systems.