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81.
The results showed that the essential oil from Piper sarmentosum has strong antifeedant and toxicity effects on Brontispa longissima. The best antifeedant and contact toxicity effects were observed in the 1st-2nd instar larvae. The essential oil also displayed a notable fumigation effect on the eggs and pupae of B. longissima. It took the control-treated insects 43.34 d to complete one generation, while the insects treated with 2000 mg/L essential oil needed 73.58 d. The essential oil was analyzed by gas chromatography/mass spectrometry and 41 components were identified. Myristicin (65.22%) and trans-caryophyllene (13.89%) were the major components. Myristicin exhibited strong antifeedant and contact toxicity effects on both the 3rd instar larvae and the imagoes of B. longissima, when it showed a significant fumigation effect on the eggs and pupae of B. longissima. Another P. sarmentosum essential oil and myristicin all showed a strong inhibiting effect on the growth and development of B. longissima along with the activity of AChE, CarE, GSTs and Na+, K+-ATPase in B. longissima larvae. 相似文献
82.
为验证链烷技术测定蝗虫食性的精确性,确定蝗虫粪便中链烷的回收率。于2007年夏季在内蒙古太仆寺旗天然草地,用优势植物羊草(Leymus chinensis)、糙隐子草(Cleistegenes squarrosa)和克氏针茅(Stipa kylovii)各500g,饲喂360只成虫的亚洲小车蝗(Oedaleus asiaticus)。试验期内每天记录蝗虫实际牧草采食量、采食成分和排粪量,利用气相色谱分析牧草和粪样的链烷含量,应用链烷技术测定蝗虫的牧草采食比例,并与实际值进行比较。结果表明,3种牧草链烷模式存在种间差异;蝗虫粪便中链烷的回收率随链烷长度的增加而线性增加;蝗虫采食羊草、糙隐子草和克氏针茅比例的测定值与实际值存在显著正相关(P<0.05),相关系数分别为0.925 5、0.956 6和0.978 2。因此链烷技术可以精确测定典型草原蝗虫的食物组成。 相似文献
83.
Palm press fibre (PPF) was obtained from two sources, a small-scale oil palm processing unit and a large-scale factory processing unit, and its chemical composition was determined. In vitro digestibility techniques were used to assess the feeding value of untreated, defatted and sodium hydroxide-treated PPF. For the NaOH treatment, 0.5 g oven-dried PPF was treated for 24 h with 5% NaOH in three ways: treated and not washed (NaNW); treated and washed (NaW); and treated after milling (NAD).The results indicate that, on a dry matter basis, PPF is low in nitrogen (12–13 g/kg), moisture (37–90 g/kg) and ash (53–62 g/kg), but high in ether extract (269–355 g/kg), neutral detergent fibre (532–768 g/kg), acid detergent fibre (375–548 g/kg) and lignin (219 g/kg). The in vitro dry matter digestibility values were low for the samples from both sources, but the large-scale factory-processed PPF had higher in vitro dry matter digestibility (0.215 vs 0.166) and in vitro organic matter digestibility (0.196 vs 0.145). Defatting the PPF and treating it with 5% NaOH solution significantly (p<0.01) improved both the dry matter and organic matter digestibility. Washing the NaOH-treated PPF resulted in a higher digestibility of dry matter as against NaNW or NAD. These results suggest that defatting and treatment with 5% NaOH would improve the feeding value of PPF. 相似文献
84.
85.
86.
Gengmei?Xing Jun?Zhang Jing?Liu Xiaoyan?Zhang Genxuan?WangEmail author Yafu?Wang 《Phytoparasitica》2003,31(5):499-514
The impacts of elevated CO2 and soil water on the population dynamics, adult fecundity and nymphal period of the bird cherry-oat aphidRhopalsiphum padi (Linnaeus) were evaluated in three experiments: (i)Combined effects of CO
2
and soil water on aphid populations. Spring wheat was grown in pots at three CO2 concentrations (350, 550 and 700 ppm) and three soil water levels (40%, 60% and 80% of field water capacity, FWC) in field
open-top chambers (OTC) and infested with the bird cherry-oat aphid. Aphid population dynamics were recorded throughout the
growing season; at the same time, adult fecundity and duration of the nymphal period were recorded. Chemical composition of
spring wheat leaves was also analyzed. (ii)Indirect effects of CO
2
concentrations and soil water on aphid adult fecundity and nymphal period. The experiment was conducted with the leaf discs method in the laboratory. Aphids were reared on leaf discs excised from
the treated wheat in OTC with different CO2 and soil water levels. (iii)Direct effects of CO
2
concentrations on aphid adult fecundity and nymphal period. Aphids were reared on leaf discs excised from the wheat grown under natural conditions. The experiment was conducted with
the leaf disc method in OTC with the three CO2 concentrations. It was found that the direct effect of CO2 concentration on aphid population parameters was minor. CO2 and soil water affected aphid population indirectly through their effects on wheat characteristics. The aphid population
under 550 ppm CO2 was far larger than the one under 350 ppm CO2, whereas the population under 700 ppm CO2 was slightly higher than that under 550 ppm CO2. The largest aphid population was obtained with the 60% soil water treatment, regardless of CO2 treatment. The effects of CO2 concentration on aphid population were, however, not significantly correlated with soil water level. Adult fecundity increased
with CO2 concentration, the highest fecundity being achieved under 60% FWC treatments. The nymphal period was not affected by CO2 concentration. The shortest period occurred under 60% FWC. Atmospheric CO2 and soil water had significant effects on the chemical composition of the wheat leaves. Aphid population size was positively
correlated with leaf water content, concentrations of soluble proteins, soluble carbohydrates and starch, and negatively correlated
with DIMBOA and tannins concentrations.
http://www.phytoparasitica.org posting Oct. 20, 2003. 相似文献
87.
The performance was compared of cows sired by Holstein, Jersey or Brown Swiss bulls out of Holstein-Friesian×Gir dams of 1/2 to 3/4 Holstein-Friesian content. The animals were kept in a single herd under the same management. The data were analysed by least-squares techniques under a model that included the fixed effects of breed of sire, Bos taurus fraction of the dam, parity, year and season of calving, and a random cow effect. Based on 480 observations, the milk yields per lactation for the Holstein, Jersey and Brown Swiss sired groups were 2821±163, 2320±61 and 2418±119 kg, respectively. The corresponding means for fat yield per lactation were 96.9±6.6, 86.8±2.5 and 92.8±4.8 kg; for protein yield per lactation were 85.3±5.1, 71.3±1.9 and 76.3±3.7 kg; for lactation length, 339±18, 283±7 and 313±14 days for fat percentage, 3.37±0.10, 3.73±0.04 and 3.77±0.07%; and for protein percentage, 3.02±0.05, 3.10±0.02 and 3.16±0.04%. The respective calving intervals were 487±24, 408±11 and 461±245 days. The yields of milk and protein per day of calving interval were similar in the Jersey and Holstein sired groups, while the former had higher yields of fat, implying that production economics might favour the smaller Jersey crosses in production systems in which the males were not reared. Crossing with Brown Swiss did not improve performance over the Holstein sired crosses. 相似文献
88.
不同饲料蛋白质水平对吉富品系尼罗罗非鱼幼鱼生长和鱼体组成的影响 总被引:11,自引:0,他引:11
用3种不同蛋白含量(23.1%、37.6%和47.9%)的配合饲料投喂吉富品系尼罗罗非鱼幼鱼78d,结果显示,①随着饲料蛋白质含量从23.1%上升到47.9%,平均日增重从0.30g/d上升到0.74g/d,3组之间的日增重和体重有显著差异(P<0.05);饲料系数从1.53下降为0.98,3组之间的饲料系数有显著差异(P<0.05)。②不同的蛋白质水平对鱼体蛋白质和脂肪的含量有影响,各组之间差异显著(P<0.05),对灰分的影响差异不显著(P>0.05)。③蛋白含量为23.1%、37.6%和47.9%的配合饲料的成本分别为2.77元/kg、3.67元/kg、4.60元/kg。④初步认为蛋白含量为37.6%的配合饲料更适合吉富品系尼罗罗非鱼苗种培育的生产需要。 相似文献
89.
An experiment was conducted to evaluate the effects of a high protein – low energy diet on body composition of feedlot lambs The objective was to assess the capability of such a diet to reduce body fat while preserving lean body mass. Three dietary regimens were compared: a typical feedlot diet (CON), barley straw at libitum (STR), and barley straw supplemented with fish meal (SFM). The latter two diets caused an energy deficit in the experimental animals. Significant treatment effects on mass of metabolic organs, body composition, and carcass data were observed. Conventional analysis of sensory data and fatty acid profiles of adipose and muscle tissue identified few significant dietary effects, yet discriminant analysis clearly separated all treatment groups. It was concluded that protein supplementation of ruminants in the catabolic state does not conserve protein mass. Given the high cost of protein supplementation, the post hoc modification of body composition of feedlot lambs is not a viable option. It is suggested that the production of feedlot lambs with a desirable degree of fatness should employ a feeding strategy dynamically adapted to the changes in protein – energy balance required by the growing ruminant. 相似文献
90.
A grazing experiment, conducted for 90 days compared the effect of polyethylene glycol (PEG) supplementation on postpartum reproductive traits and productivity of suckling goats grazing Acacia cyanophylla Lindl. A total of 54 native adult goats (34.4 ± 5.49 kg) were randomly allocated, 24 h after kidding, to 2 treatment groups balanced for age and the number of reared kids. Goats in both treatment groups designed C and PEG grazed in acacia for approximately 5 h every day and received each on daily basis 0.3 and 0.4 kg of hay and concentrate respectively. In addition, goats in treatment PEG were initially supplemented with 10 g/day of PEG and this supplement was then increased to 20 g /goat/day over the last 60 days of the trial. Goats receiving PEG tended (P > 0.05) to spend more time browsing acacia than those in treatment C. There were no treatment effects on live weight change of the goats, growth of their kids until 90 days of age or composition of their milk in terms of fat, protein and urea contents. Similar proportions of 74.1 and 77.8% of goats resumed postpartum ovulation with a mean ovulation rate of 1.50 ± 0.61 and 1.67 ± 0.47 (P > 0.05) in respectively the PEG and C treatments. PEG supplementation was associated with an increase (P < 0.05) in ovulation rate at the second postpartum ovulation occurring approximately 27 days after the application of the nutritional treatments (1.76 ± 0.60 versus 1.25 ± 0.45); 9 of the 13 goats ovulating in the PEG treatment were bearing more than one corpus lutuem in comparison to only 3 out of 12 females in the C group (P < 0.05). The likely increased availability of proteins in the PEG receiving goats could explain their higher ovulation rate. 相似文献