Natural dietary additive yellow loess as potential antibiotic replacer in Japanese eel,Anguilla japonica: Effects on growth,immune responses,serological characteristics and disease resistance against Edwardsiella tarda

The present experiment was conducted to evaluate the efficacy of an additive derived from the nature as an alternative of dietary antibiotic in Japanese eel, Anguilla japonica. Six experimental diets were formulated to contain no antibiotics or additive (yellow loess/YL) (control/CON), three graded levels of yellow loess at 5 (YL₅), 10 (YL₁₀) and 20 g/kg (YL₂₀), oxytetracycline at 5 (OTC) and amoxicillin at 10 g/kg amoxicillin (AMX) of diet. Weight gain (WG) and specific growth rate (SGR) from fish fed CON or YL₅ diets were significantly lower than those of fish fed YL₂₀ or OTC diets. Among non‐specific enzyme, lysozyme activity of fish fed YL₂₀, OTC or AMX was detected to be significantly higher than that from fish fed CON or YL₅ diets, whereas superoxide dismutase (SOD) activity of the fish fed CON was significantly lower than that for fish fed other experimental diets. Challenge test with bacteria, Edwardsiella tarda, showed improved disease resistance among the fish fed different levels of natural additive without any statistical difference from those fed antibiotics (OTC and/or AMX) supplemented diets. Therefore, these results demonstrated the potential of natural feed additive, yellow loess to replace oxytetracycline and/or amoxicillin in Japanese eel, A. japonica.     

Highlights of progress in silage conservation and future perspectives

Highlights of progress in the production of silage over the past 50 years include the introduction of improved hybrids of maize (Zea mays L.), the forage harvester, the big baler, polyethylene covering for horizontal silos, stretch‐wrap film for bales and novel additives designed to improve the fermentation and aerobic stability of silage. The key biochemical pathways in the silage fermentation have been described together with the effects of microbial and chemical additives on fermentation and aerobic stability during the feed‐out phase. The significance of oxygen and water in silage fermentation has been quantified and efficacy of covering silos has been established, with recent progress in the development of oxygen barrier film. Future perspectives include improving food safety and animal health by increasing the hygienic quality of silage, reducing the environmental impact of silage by decreasing loss of nitrogen to soil and atmosphere, reducing methanogenesis in the rumen and increasing methane yield from silage as biofuel, and the use of silages as feedstocks for multiple end uses in biorefineries.     

新型菊芋秸秆-烟煤混合固体燃料添加剂的选择与燃烧性能分析

在研制新型菊芋秸秆-烟煤混合固体燃料的基础上,筛选不同添加剂[MgCO3、CaCO_3、Al2O_3、Al_2Si_2O_5(OH)_5]优化燃料,以提高生物质混合固体燃料的燃烧性能。将四种添加剂以3%比例(质量比)与菊芋秸秆-烟煤混合固体燃料混合,比较了不同添加剂对混合固体燃料的灰分、结渣率、放热量、烟黑、灰熔点、烟气成分等的影响。结果表明:四种添加剂对酸性气体有明显的吸附作用,且能有效降低混合固体燃料的结渣率,其中CaCO_3添加剂使混合固体燃料的灰分含量、烟黑的林格曼指数下降最为明显。这表明,CaCO_3添加剂能有效缓解混合固体燃料中的灰分、烟黑、酸性气体的生成,提高其燃烧性能,是一种较为理想的新型菊芋秸秆-烟煤混合固体燃料添加剂。     

Detection of additive and additive×environment interaction effects of QTLs for yield‐component traits of rice using single‐segment substitution lines (SSSLs)

Additive effects (A) and additive‐by‐environment interactions (A×E) for five rice yield components were analysed using 20 SSSLs under mixed linear model methodology. Thirty‐one QTLs were detected. Different yield components have different QTL‐by‐environment (Q×E) interaction patterns. No A×E interaction effects were detected for the four QTLs for panicle number (PN). Four QTLs detected for spikelets per panicle (SPP) had A×E interactions. Five of seven QTLs detected for grains per panicle (GPP), two of 10 QTLs detected for 1000‐grains weight (GWT) and three of six QTLs detected for seed set ratio (SSR) showed significant A×E interaction. Most of these QTLs were distributed in clusters across the genome. The complexity of linkage and pleiotropy of these QTLs plus environmental effect may result in the diversity of the yield phenotype in the SSSLs. Only S19 exhibited a significant increase in yield with a predicted gain by 281.58 kg ha^?1. The results may be useful to design a better breeding strategy that takes advantage of QTL‐by‐environment interaction effects in each of the SSSLs.     

Feeding of yeast (Candida spp.) improves in vitro ruminal fermentation of fibrous substrates

In vitro gas production technique (IVGPT) was used with the objective of determining the inclusion effect of live cells of two strains of Candida yeast on in vitro ruminal fermentation of two fibrous substrates. In order to achieve this, two experiments were performed: A) using oat straw (Avena sativa) as substrate; B) using alfalfa hay (Medicabo sativa) as substrate, comparing the effect of two different strains of Candida genre, both isolated from the rumen, on the mentioned substrates. Levica 25 (Candida tropicalis) yeast belongs to the culture collection of the Institute of Animal Science, Cuba, and Levazoot 15 (Candida norvegensis) yeast is part of the collection of the Faculty of Zootechnology and Ecology of the Autonomous University of Chihuahua, Mexico. Both strains demonstrated their potential in activating the ruminal fermentation. They stimulated (P<0.0001) the ruminal fermentation of the substrates under study. However, the Levazoot strain stimulated the dry matter (DM) fermentation of alfalfa in 21.43%, more than Levica 25. It is concluded that there is an influence of yeast strain and diet on the rumen environment and, therefore, it is important to select the appropriate strain in every production condition.     

Habitat associations of dolphinfish larvae in the Gulf of Mexico

The aim of this study was to investigate the role of the northern Gulf of Mexico (Gulf) as essential habitat of common dolphinfish (Coryphaena hippurus) and pompano dolphinfish (C. equiselis) during early life and to characterize conditions in which they were found. Eight ichthyoplankton surveys were conducted during the summer months from 2007 to 2010 in northern Gulf waters off Texas and Louisiana (26–28°N, 87–93°W), during which 1145 dolphinfish larvae were collected. C. hippurus, the dominant dolphinfish species, were collected in 57% of sampling sites with an overall mean density of 0.73 larvae 1000 m^?3, whereas C. equiselis were only collected at 18% of sites with a mean density of 0.12 larvae 1000 m^?3. Generalized additive models (GAMs) were used to examine the relationship between several environmental parameters and C. hippurus presence/absence and density. Both presence/absence and density GAMs indicated that catches of C. hippurus larvae increased near fronts and eddies and that increased abundances were most strongly associated with higher salinities and cooler temperatures. In addition, our models showed that C. hippurus larvae were positively associated with C. equiselis larvae, suggesting that C. hippurus and C. equiselis use similar habitats. Results of this study indicate that the Gulf may represent important spawning and/or nursery habitat of dolphinfishes and that mesoscale features and physicochemical conditions influence the distribution and abundance of C. hippurus larvae in this region.     

白僵菌可湿性粉剂的研制

以白僵菌孢子粉为原药,硅藻土为主要载体,通过单因素和正交设计筛选合适的润湿剂、分散剂等助剂配方比例,研制出性能优良的白僵菌可湿性粉剂。确定配方为：白僵菌分生孢子粉20%; NNO7%; 农乳32082%; 拉开粉5%; 十二烷基硫酸钠2%; 硅藻土加齐至100%。质量检测结果表明：该配方润湿时间<1min,悬浮率可达到75%以上,其他各项指标均符合可湿性粉剂的要求。     

鸡粪施入农田土壤的氨挥发研究

在北京海淀区东北旺乡利用风洞法氨挥发测定系统,研究了不同施肥方式、施肥量和添加剂对鸡粪在农田施用过程中氨挥发的影响。结果表明,施肥方式显著影响鸡粪氨挥发,试验期间在田间裸地24000kg·hm^-2施肥量下,表施的累积氨挥发氮损失为19．8％,而表施后立即深翻5-9cm,氨挥发损失为3．3％;不同施肥量下,24000kg·hm^-2之比12000kg·hm^-2和8000kg·hm^-2的氨挥发损失分别减少2．1％和4．9％,但统计差异不显著;锯末对鸡粪氨挥发没有起到抑制作用,未添加锯末处理的氨挥发损失为19．5％,而添加锯末处理的氨挥发损失为21．1％;过磷酸钙对鸡粪氨挥发抑制效果显著,未添加过磷酸钙处理的氨挥发损失为31．8％,而添加过磷酸钙处理的氨挥发损失为21．9％,比未添加降低了31．1％。     

核苷酸对动物摄食、生长与免疫功能的影响

饲料中的核苷酸对动物生长发育和免疫功能等具有重要作用。核苷酸作为一种无毒无害无残留的新型饲料添加剂,在动物营养方面有很大的发展前途。近年来国内外学者对核苷酸的研究逐渐增多。本文从促生长、诱食和改善免疫功能等方面对核苷酸在动物营养方面的应用做一综述。     

不同催情药物对提高母豪猪繁殖性能的影响

为探讨添加不同催情药物对豪猪产仔数、平均初生重等繁殖性能的影响。选取2岁左右、胎次及产仔数相近的母豪猪100头,随机分为5组,每组20头,分别饲喂5种不同的日粮：对照组为基础日粮,试验Ⅰ组为基础日粮＋催情散;试验Ⅱ组为基础目粮＋中草药制剂;试验Ⅲ组为基础日粮＋“牲命1号”;试验Ⅳ组为基础日粮＋胎盘,进行3个月的饲养试验,并跟踪记录受配母豪猪数、产仔母豪猪数、产仔数、平均初生重等繁殖情况。结果表明：在基础日粮中添加中草药制剂对提高豪猪繁殖率优于在日粮中添加催情散、“牲命1号”、胎盘,效果最佳。