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1.
河南农业大学烟草育种课程组全体教师对《烟草育种学》的教学内容、教学方式和考核形式进行了系列改革。近年来的教学实践表明,这些改革措施充分调动了学生学习的主动性,达到了改善教学质量的效果,为高等农业院校该课程的教学提供一定的参考。 相似文献
2.
The present experiment was conducted to investigate the effects of dietary protein to carbohydrate ratios on growth and body composition of juvenile yellow catfish, Pelteobagrus fulvidraco . Nine diets were formulated to contain three protein levels (30%, 36% and 42%), each with three carbohydrate levels (24%, 30% and 36%). Each diet was randomly assigned to triplicate groups of 20 fish (initial mean body weight: 8.24±0.20 g) in indoor flow – through fibreglass tanks. The experiment continued for 8 weeks. Weight gain and specific growth rate were similar for the fish fed the 36% and 42% protein diets but higher than that fed the 30% protein diet. At the 36% protein level, carbohydrate contents varying from 24% to 36% ( P / E ratio of 24.0–28.2 mg protein kJ−1 ) had no significant effects on growth performance and feed utilization ( P >0.05). Protein efficiency ratio tended to increase with dietary carbohydrate level at the same protein level. Dietary treatments significantly influenced body composition ( P <0.05), but not the condition factor, viscerosomatic index, hepatosomatic index and intraperitoneal fat ratio ( P >0.05). Based on these observations, 36% protein and 24–36% carbohydrate with the P / E ratio of 24.0–28.2 mg protein kJ−1 seemed suitable for optimal growth and feed utilization, and carbohydrate could cause protein-sparing effect in diets for juvenile yellow catfish. 相似文献
3.
The effect of prebiotic xylooligosaccharides (XOS) on the growth performance and digestive enzyme activities of the allogynogenetic
crucian carp, Carassius auratus gibelio, was investigated. XOS was added to fish basal semi-purified diets at three concentrations by dry feed weight: diet 1, 50 mg kg−1; diet 2, 100 mg kg−1; diet 3, 200 mg kg−1, respectively. Twelve aquaria (n = 20) with three replicates for each treatment group (diets 1–3) and control treated without XOS were used. Weights of all
collected carp from each aquarium were determined at the initial phase and at the end of the experiment, and the carp survival
was also determined by counting the individuals in each aquarium. After 45 days, there were significant differences (P < 0.05) in the relative gain rate (RGR), and daily weight gain (DWG) of diets 1–3 were compared with the control. However,
the survival rate was not affected (P > 0.05) by the dietary treatments. For enzymatic analysis, dissection produced a crude mixture of intestine and hepatopancreas
of each segment to measure. The protease activity in the intestine and hepatopancreas content of fish in diet 2 (487.37 ± 20.58 U g−1 and 20.52 ± 1.93 U g−1) were significantly different (P < 0.05) from that in the control (428.13 ± 23.26 U g−1 and 12.81 ± 1.52 U g−1) and diet 3 (428.00 ± 23.78 U g−1 and 14.04 ± 1.59 U g−1). Amylase activity in the intestine was significantly higher for diet 2 compared to diet 1 and the control. As for amylase
in the hepatopancreas, assays showed higher activity in diet 2 (P < 0.05) compared to the rest. 相似文献
4.
以农业高校教师为研究对象,通过问卷调查,对教师的工作满意度现状、影响因素进行了分析。研究显示,当前农业高校教师的工作满意度整体不高;上级管理、发展机会、生活条件正向影响工作满意度,工作压力负向影响工作满意度,而人际关系则可以显著调节上述关系。据此,提出了提高教师工作满意度的对策。 相似文献
5.
6.
Youji Wang Menghong Hu Weimin Wang Ling Cao Yi Yang Biping Lü Rongrong Yao 《Aquaculture International》2008,16(6):539-549
The diel feeding rhythm and ontogenesis during early life stage of loach Misgurnus anguillicaudatus were investigated under experimental conditions (light: L 06:00–18:00, D 18:00–06:00 h). Morphological and behavioral developments
of loach from newly hatched to 40 days after hatching were observed. Larvae were able to prey on daphnia 3–4 days after hatching
at 23 ± 0.5°C. As the larvae grew, they showed an increasing feeding capacity and a distinct feeding rhythm. Feeding intensity
and incidence for day-4 larvae were highest at 10:00 and 16:00 h. The highest levels of feeding intensity for day-12 larvae
occurred at 08:00, 12:00, and 18:00 h as did feeding incidence. By day 20, when the larvae metamorphosed, the highest levels
of feeding intensity occurred at 06:00, 18:00, and 24:00 h and were concurrent with the highest feeding incidence. After metamorphosis,
feeding capacity had again increased considerably and, in contrast to the earlier stages before day 20, feeding intensity
for day-30 juveniles peaked at 05:00 and 20:00 h, about 1–2 h after the maximum feeding incidence. The feeding rhythm of loach
juveniles at day 40 was almost the same as the day-30 juveniles. The estimated maximum daily feeding rates were 43.1%, 33.4%,
19.0%, 12.8%, and 5.8% of body weight on days 4, 12, 20, 30, and 40, respectively. Thus, loach was found to have different
feeding rhythms in the pre- and post-metamorphosis stages, with the highest feeding activity in daytime during the larval
planktonic stage before metamorphosis, and intensely nocturnal feeding behavior during the juvenile benthic stage after metamorphosis. 相似文献
7.
Gao Zexia Wang Weimin Yang Yi Khalid Abbas Li Dapeng Zou Guiwei James S. Diana 《Fish physiology and biochemistry》2007,33(3):213-222
The peripheral blood cells of one-year-old Chinese sturgeon (Acipenser sinensis) have been studied by light microscopy and transmission electron microscopy. The erythrocyte count was 84.86 × 104 cell mm−3 in the peripheral blood of the fish and that of leukocytes was 2.24 × 104 cell mm−3. The erythrocytes and four main types of leucocyte—thrombocytes, lymphocytes, granulocytes (including neutrophils and eosinophils),
and monocytes, were identified in the peripheral blood. In addition to normal erythrocytes, reticulocytes and division of
erythrocytes were observed. Thrombocytes were the most numerous among the leukocytes, and the number of neutrophils with lobated
nuclei was larger than for other fish. The structures of the erythrocytes, lymphocytes, monocytes, granulocytes, and thrombocytes
of the fish were studied. The erythrocytes were almost completely devoid of organelles, except for some mitochondria and granules.
A large number of vacuoles and a few organelles were observed in cytoplasm of the monocytes. There were many microvilli on
the membrane and pseudopodia-like cytoplasm bulge in the lymphocytes. The neutrophils were round or oval in shape with bilobed,
trilobed, or multilobed nuclei whereas the eosinophils had big special granules, dark stained. There were many vesicles in
some thrombocytes, which were related to its phagocytosis; some thrombocytes had almost no cytoplasm or organelles. 相似文献
8.
左伏3号山楂的组织培养和常温离体保存研究 总被引:1,自引:0,他引:1
以伏山楂品种"左伏3号"为试验材料,进行组织培养和常温离体保存研究。结果表明:左伏3号启动培养的最佳培养基是MS+6-BA1.0 mg.L-1+IAA0.08 mg.L-1,成活率达到93.3%;继代培养的最佳培养基是MS+6-BA0.8 mg.L-1+NAA0.01 mg.L-1,繁殖系数达到5.5;生根培养在1/2MS+NAA0.5 mg.L-1上生根率(31.7%)最高,移栽可成活。0.4~2.0 mg.L-1的PP333不适宜左伏3号的常温离体保存,而CCC 40 mg.L-1和ABA2.0 mg.L-1比较适合。 相似文献
9.
10.
[目的]本研究旨在对黄河首曲-玛曲湿地的沼生植物进行群系分类。[方法]采用样方法,同时参考植物标本,对玛曲湿地的沼生植物进行调查研究。[结果]玛曲湿地沼生植物的群落类型可分为莎草沼泽和杂类草沼泽2大类共4个群系。建群种主要包括华扁穗草(Blysmussinocompressus)、裸果扁穗苔草(Blysmocarex nudicarpa)、槽秆荸荠(Eleocharis valleculosa)和两栖蓼(Polygonum amphibium);亚建群种主要包括褐鳞苔草(Carex brunnescens)、沿沟草(Catabrosa aquatica)、甘肃嵩草(Kobresia kansuensis)、两栖蓼(Polygonum amphibium)和火绒草(Leontopodiumalpinum)。群落总盖度在5%~90%之间;主要分布在河道洼地、河漫滩、沟谷洼地、阶地陡坎洼地、沟源洼地等常年积水的地方,地下水位埋深大都在20~30cm。[结论]进行沼生植物的群系分类研究,可以为玛曲湿地草原的生态恢复治理提供科学依据。 相似文献