Determination of annual reproductive cycle in male sterlet,Acipenser ruthenus using histology and ultrasound imaging

Fish Physiology and Biochemistry - The aim of this study was to evaluate seasonal testicular development in the cultured sterlet, Acipenser ruthenus. During annual sexual cycle of male sterlet,...     

收割机前部扩充配件对降低油菜收获损失的作用（摘选）

如今,伊朗油菜种植已经在其国内各地发展起来。然而,在整地、种植和收获过程中仍然存在一些问题。因此,需要采用新技术进行机械化收获。目前,谷物联合收获机生产公司除了生产常用设备,也生产一些安装在割台上的扩充配件。机械化收获系统尤其是常用的收获割台存在有相当大的损耗,同时熟练程度和需要特殊的油菜收获配套设备也是造成损失的原因之一。该试验研究一种割台和两种割台扩充配件对油菜收获损失的影响,从而确定损失量以及造成损失的原因。试验中涉及到一种常见割台,以及伊朗制造的采用机械侧刀切割器的Hamed割台扩充配件和采用液压侧刀切割器的Bizo割台扩充配件。试验采用随机完全区组设计,设6次重复。利用安置的托盘测定收获损失量。结果表明,随着割台运禾螺杆与切割器间距离的加大,割台扩充配件能降低损失量。因此,从总损失量考虑,常用割台与其他两种扩充配件相比差异显著。普通割台损失量为599 kghm2,而采用侧面垂直切割可以减少71 kghm2。此外,使用液压系统替代机械系统以及使用双层切割器替代单层刀杆都有助于降低损失量。试验结果显示,破损种子量为39.6 kghm2,占总产量的1.12%。试验结果是令人满意的,同时改善了联合收获机的性能。通过使用割台扩充配件有利于降低收获中的损耗。      

A REVIEW OF PRODUCTION FRONTIER RESEARCH IN AQUACULTURE (2001–2011)

Most research works on the production frontier in aquaculture focus on efficiency measurement using either Stochastic Production Frontier (SPF) or Data Envelopment Analysis (DEA). The studies on productivity growth in aquaculture were limited, perhaps due to lack of time-series data. Nevertheless, total factor productivity analysis (TFP) in fish farms has started gaining popularity in recent years. In addition, the majority of the efficiency studies have centered on technical efficiency analysis but substantial increases in the output levels can be fully realized through improving overall economic efficiency. Therefore, this review suggests that future research should estimate all three efficiency indices (i.e., technical, allocative and economic efficiencies).     

Fish meal replacement with rice protein concentrate in a practical diet for the Pacific white shrimp, Litopenaeus vannamei Boone, 1931

Replacement of fish meal (FM) with rice protein concentrate (RPC) as a practical diet for the Pacific white shrimp, Litopenaeus vannamei, was evaluated. Five isonitrogenous (36.6% protein) diets, formulated by replacing 0, 25, 50, 75, and 100% of FM by RPC, were fed to shrimp (initial weight of 6.99 ± 0.08 g) five times daily to satiation for 60 days. Relatively high final weight (FW 17.64–18.25 g) and weight gain (WG 10.81–11.39 g) were obtained in treatments up to 50% of the plant protein inclusion. Above this inclusion level, FW (14.93–14.35 g) and WG (7.68–7.23 g) were reduced. Survival was high (≥95%) and similar for all diets. There were no significant differences (P > 0.05) in tail-muscle composition (moisture, protein, lipid, and ash) among different dietary treatments. Dispensable and indispensable amino acids of the tail muscle of shrimp fed with 25, 50, and 75% RPC were significantly higher than the FM (0%) and 100% RPC diets. A decreasing trend in apparent digestibility coefficient (excluding dry matter) for crude protein (90.52–52.41), ether extract (94.11–80.03), organic matter (87.25–50.16), and gross energy (89.41–55.24) was observed at higher RPC inclusion rates. The results suggest that RPC meal can be a potential candidate for FM replacement up to 50% of the protein in shrimp diets.     

Sulfur uptake and translocation in maize (zea mays) grown in a high pH soil treated with elemental sulfur

A glasshouse experiment was conducted to elucidate the influence of elemental sulfur (S) application rates (0, 0.5, 1.0, and 2.0 g S kg^?1 soil) on the release and uptake of S at 0, 20, and 40 days after incubation. Results showed that there was a progressive upward trend in maize leaves, stem, and root S content with application of elemental S. However, maize production followed a nonlinear model. Plants grown in untreated soils suffer from S deficiency and addition of elemental S at a rate of 0.5 g S kg^?1 soil alleviated S deficiency. The decrease in maize performance due to the highest S application rate was not related to S toxicity. The greatest leave, stem, and root productions were obtained at S concentrations of 0.41, 0.58, and 0.2%, respectively. Overall, application of elemental S at a rate of 0.5 g S kg^?1 soil is recommended for maize performance improvement.     

商业生产条件下香辣宝6930对肉鸡生产性能的影响

在欧洲,产品香辣宝6930(含3种植物提取物的有效成分:香芹酚、肉桂醛和辣椒素)作为抗生素促生长剂替代物在饲料中添加应用研究已经超过10年。然而,有关该产品在中国商业生产条件下的应用效果还未有过正式报道。本试验在同一栋畜舍内分2个批次进鸡重复相同的对比试验,试验分对照组和试验组,试验组是将对照日粮能量浓度降低25kcal/kg后,额外添加香辣宝6930100g/t到饲料中,观察其对肉鸡生产性能和成活率的影响效果。结果表明,在最初的2—4周,香辣宝对肉鸡体重增长有促进作用但尚未达到统计学的显著水平,但2个批次试验的料重比均减少2%以上;但试验最后2周和全期统计结果的增重和料重比与对照相比均有显著提高(3.5%,P0.05);从2个批次不同健康状态试验鸡的比较来看,香辣宝6930对健康状态稍差的鸡的成活率改善状况与对照相比更加明显(6.73%,P0.05)。     

马来西亚未尽利用热带水果概况

未尽利用热带水果,即在当地消费和医用的非贸易热带水果,未普及化,生长于野外,季节性强,但富含多酚类化合物、类胡萝卜素、花青素、脂肪酸、矿物质和氨基酸,因而具有一定的开发潜力。在马来西亚,热带水果丰富多样,主要有普通水果、观赏水果、特有水果、野生水果和高地水果,但大部分水果都未能充分利用,其中,典型的有罗望子、巴杖果、砂拉越芒果、钮扣山竹、榴莲、莲雾、挂尼芒果、野红毛丹和蛇皮果。这些水果可以分为3个类型：具有贸易开发潜力的主要包括无花果（Ficus sp.）、罗望子（Garcinia atroviridis）、尖必达（Artocarpus integer）、鲜花木果（Lepisan-thes alata）、野榴莲（Durio sp.）、橄榄木（Spondias cytherea）、菠萝蜜（Artocarpus heterophullus）、槟榔（Areca catechu）、野红毛丹（Nephelium ramboutan-ake）、蛇皮果（Salacca zalacca）和面包果（Artocarpus altilis）;具有适于当地人们利用潜力的水果种类包括木胡瓜（Averrhoe bilimbi）、榔拜果（Baccaurea motteyana）、单贝果Baccaurea macrocarpa）、喃喃果属（Cynometra cauliflora）、西柚（Dialum indum）、黄肉榴莲（Durio kutejensis）、野生山竹（Garcinia hombroiniana）、野檬果（Garcinia parvifolia）、巴杖果（Mangifera feotida）、醋栗（Phyllanthus emblica）、蒲桃（Syzygium jambos）;不具有经济利用开发潜力的水果种类包括哥露比（Salacca conferta）、青枣（Zizyphus mauritiana）、木奶果属（Baccaurea polyneura）、野檬果（Garcinia parvifolia）、番龙眼（Pometia sp.）、赤才果（Leppisanthes rubiginosa）、波漆果（Bouea microphylla）、蛋黄果（Pouteria campechiana）和仙都果（Sandoricum koetjape）。目前,有关未尽利用水果研究仍处于初期阶段,有必要使这些水果更为普及并得到有效利用,因此,政府和私人组织须采取一些措施以促进这些水果的消费。今后需对这些水果的营养成分、抗氧化作用以及疗效进行深入研究。     

Protein and energy nutrition of brook trout (Salvelinus fontinalis) at optimal and elevated temperatures

The digestible protein (DP) and digestible energy (DE) requirements for maintenance and growth of brook trout (Salvelinus fontinalis) were determined using a factorial model at either optimum (15 °C) or elevated temperature (19 °C). Several key parameters of the factorial model were measured using a series of inter‐related studies. The maintenance requirements for DP and DE were 0.10 gDP kg^?0.69 day^?1 (15 °C) and 0.31 gDP kg^?0.78 day^?1 (19 °C), and 34.86 kJDE kg^?0.84 day^?1 (15 °C) and 46.14 kJDE kg^?0.86 day^?1 (19 °C). The total requirements for DP were 0.10 gDP kg^?0.69 day^?1 + 2.14PG (protein gain) (15 °C) and 0.31 gDP kg^?0.78 day^?1 + 1.98PG (19 °C). The total requirements for DE were 36.86 kJDE kg^?0.84 day^?1 + 1.58EG (energy gain) (15 °C) and 46.14 kJDE kg^?0.86 day^?1 + 1.64EG (19 °C). The partial efficiencies for growth were 0.47 (15 °C) and 0.51 (19 °C) for protein, and 0.63 (15 °C) and 0.61 (19 °C) for energy. Nutrient gain was lower at the elevated temperature; however, feed formulation for brook trout should be adjusted to match changes in nutrient requirements at different culture temperatures. The protein and energy requirements model will be useful for developing commercial feeds and feeding charts for brook trout.