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81.
Microplate assay technique for estimation of esterase activity in a single insect was used in combination with dose mortality bioassays to detect pyrethroid resistance in three strains of Helicoverpa armigera and to study the frequency of pyrethroid resistant individuals within the population of the same strain at two larval stages, third and fifth instar. The third and fifth instar larvae of the field strains i.e., Nagpur strain and Delhi strain that displayed high degree of resistance towards deltamethrin, had higher esterase activity compared to a susceptible laboratory strain. The frequency distribution of individuals with elevated esterase activity above 1.00 absorbance unit was correlated with the resistance level of the strains. The frequency of resistant individuals in the third instar larvae of Nagpur strain and Delhi strain were 29% and 23%, respectively compared to 4% in the susceptible strain. The resistant individuals in the resistant strains have markedly increased in the fifth instar larvae with a frequency distribution of 63% and 90% in Delhi strain and Nagpur strain, respectively, while only 14% of individuals was found to have elevated esterase activity in the susceptible strain. The results demonstrated the role of esterase in pyrethroid resistance in H. armigera. Microplate assay proved to be a rapid and reliable biochemical technique for monitoring of pyrethroid resistance in H. armigera.  相似文献   
82.
Three hundred Oreochromis niloticus were divided into five groups; the control fish (CNT) were fed a basal diet, beta glucan (βG) group was fed 0.5 g/kg?1 βG, atrazine (ATZ) group was exposed to 1/5 96‐hr LC50 (1.39 mg/L) ATZ, the (βG/ATZ) group was fed βG while being exposed to ATZ, and the (βG then ATZ) group was supplemented with βG for fifteen days before exposed to ATZ. ATZ exposure caused a decline in growth that was ameliorated by βG. ATZ reduced the levels of total and different types of leucocytes. Additionally, ATZ exposure caused reductions in total proteins, globulins, α 1‐globulin, α 2‐globulin, ?‐globulin, immunoglobulin M, lysozymes, superoxide dismutase, nitric oxide and catalase but increases in hepatic transaminases and malondialdehyde without any variations in albumin and β‐globulin. Exposure to ATZ also resulted in a rise in the mRNA level of IL‐8. In contrast, expression of IgM, SOD and CAT were decreased in the tilapias exposed to ATZ. Exposure to ATZ increases the susceptibility response to Aeromonas sobria challenge, as indicated by an increase in cumulative mortality post‐challenge. Supplementation with βG fifteen days before (βG then ATZ group), counteracted the adverse effects of ATZ on the immune, biochemical and antioxidants values, though only slight alleviation was observed with simultaneous treatment (βG/ATZ group). Our results established that ATZ has adverse impacts on immune responses, antioxidant equilibrium and its related genes. While, supplementation with βG before exposure to ATZ may be valuable for counteracting the possible damage caused by ATZ water pollution than its simultaneous treatment with ATZ.  相似文献   
83.
The present study was designed to investigate cotton response to different salinity levels at different K/Na ratios of irrigation water.
The salinity levels in irrigation water were 3200 and 6400 mg/1 and the control treatment had a 320 mg/L. Potassium/Sodium ratios in irrigation water were 1: 9 and 1: 4.
Some agronomic traits were studied as well as leaf water Potential (LWP), and leaf samples were taken for elemental analysis.
Statistical analysis showed that increasing total salinity of irrigation water reduced seed yield and total dry weight of cotton but not number of total or open bolls. Lower K/Na ratio (1:9) was of benificial effects on most agronomic traits.
Increasing salinity of irrigation water caused an increase in Na, but not K or Ca content of the cotton leaves; while decreasing K/Na ratio in the saline irrigation water decreased the K/Na ratio in the leaves. Lower leaf water potential was found to be associated with higher levels of both water salinity and K/Na ratio.
A strong relationships were found between cotton seed yield, LWP and K/total bases content in leaves. Ionic content relations (K/Na and K/total bases content) were found to be of a strong association with LWP.
In brief, it could be concluded that increasing K to certain extent; K/Na (1: 9) could be useful in irrigating cotton plant with high water salinity.
The benificial effects of potassium additions to diminish the salinity effects in cotton may be the consequence of improved plant water relations, as well as the status of ion relationships.  相似文献   
84.
Exposing growing and adult New Zealand White (NZW) female rabbits to severe heat stress (temperature–humidity index = 28.9) during summer adversely affected their growth and reproductive traits. The traits that declined significantly (p<0.01) were the live body weight, daily weight gain and feed intake of growing rabbits, and the litter size and litter weight at weaning (p<0.05) and the pre-weaning weight gain of pups (p<0.01) for adult females. The conception rate declined considerably with heat stress. The declines in the values of the digestibility coefficients due to heat stress were 7.9% (p<0.05) for dry matter (DM), 8.1% (p<0.05) for crude protein (CP) and 1.0% for crude fibre (CF). The traits that increased significantly (p<0.01) due to heat stress were water intake, water/feed ratio and rectal temperature in growing rabbits and pre-weaning mortality for adult females.Alleviation of heat stress in the growing and adult female NZW rabbits was more efficient with drinking cool water (10–15°C; between 10:00 and 17:00) than with supplementation with palm oil (as a source of energy) or natural clay (as a natural enhancer to growth and milk production). Supplying the animals with cool drinking water gave the highest body weight and weight gain, conception rate, litter size and weight and digestibility coefficients for DM and CP and the lowest rectal temperature, respiration rate and pre-weaning mortality.The loss in rabbit production pertaining to heat stress estimated from the percentages of decline in conception rate×pre-weaning mortality×litter weight at weaning was 73.0%. The provision of cool water restored 11/12 of heat loss.  相似文献   
85.
Florfenicol, a monofluorinated analogue of thiamphenicol, has antibacterial activity against a broad spectrum of bacterial strains, including enteric bacteria that are resistant to chloramphenicol and thiamphenicol. The pharmacokinetics of florfenicol was studied following a single intravenous bolus or intramuscular injections at a dose of 20 mg/kg body weight, in five healthy goats. Serum florfenicol concentrations were determined using two analytical methods: microbiological assay and high-performance liquid chromatography (HPLC). Pharmacokinetic analysis was performed using redundant routine equations and the results derived from each method were compared. While florfenicol was detected for up to 4 and 8 h after administration by the bioassay, the drug was recovered in serum after 12 and 24 h by HPLC following intravenous and intramuscular injections, respectively. Comparison of the concentration profiles obtained by the two methods revealed substantial differences in the resultant kinetic data. Values for the initial serum concentration, elimination half-life, the area under the serum concentration-time curve, the mean residence time, and the systemic bioavailability were significantly (P < 0.01) higher when florfenicol concentrations were determined using HPLC. In conclusion, differences between analytical methodologies should be considered when interpreting the kinetic data for clinical use. However, both the hepatic biotransformations and the interchangeability of enantiomers need further investigation.  相似文献   
86.
A pot experiment was conducted in lath house to study the response of six month-old seedlings of sour orange (Citrus aurantium L.) irrigated with salinity water (1, 2 or 4 ds/m) for four month. The seedling was sprayed with putrescine at 0, 150 or 300 mg/L concentrations for three times with month interval, for investigation the effects of putrrescine spraying on hormonal changes in sour orange seedlings under salt stress. One month after the last putrescine application, the leaves of the vegetative shoots were picked for endogenous plant hormone determination. The results indicate that increasing level of irrigation water salinity to 4 ds/m significantly increased ABA, Put and SA; whereas, decreasing IAA and GA in leave. Spraying vegetative canopy with putreseine at 300 mg/L increased 1AA, SA, ABA and Put, while decreased GA. It can be concluded that the adverse effects of high salinity irrigated water on endogenous plant hormone can be ameliorated, to some extent, by exogenous application of Put at 150 mg/L or 300 mg/L concentration.  相似文献   
87.
Two experiments were carried out at Giza Agric. Res. St., Agric. Res. Centre, Ministry of Agric, Egypt, during 1981 and 1982 seasons on cotton cultivar Giza 75 ( Gossypium barbadense L.) to investigate the influence of nitrogen fertilization rates (72, 144 or 216 kg N/ha), phosphorus levels (36 or 72 kg P2O5/ha) and three growth regulators (IAA, IBA or NAA), each was applied to cotton plants at 10 ppm and sprayed three times (70, 85 and 100 days after sowing), on cotton seed, protein and oil yields and oil properties. A randomized complete block design, with four replications treatment combinations was used.
The combined analysis of the results of the two seasons revealed that, cottonseed, oil and protein yields/ha increased by raising N- and P-levels and under the application of growth regulators. Seed index increased by raising the added-N and the applied growth regulants. No detectable effect of P-levels was observed. The seed oil percentage decreased, while the protein percentage increased by raising N-rate. Application of growth regulators and high P-level increased the seed oil percentage, while the seed protein percentage was not affected. The seed oil properties, i.e. acidity, saponification and iodine values, tended to decrease slightly by increasing N-rate and the application of growth substances, while a reverse trend was noticed by raising P-level. The mean values of oil specific gravity and refractive index did not show any definite response.  相似文献   
88.
Subterranean vetch [Vicia sativa ssp. amphicarpa (Dorth.) Aschers & Graebn.] is native to disturbed grasslands of the Mediterranean basin where heavy grazing, seasonal drought and erosion act as strong selection forces. It produces two pod types, above‐ground and 5 cm below the soil surface. Unlike subterranean clover (Trifolium subterranean L.), which buries its seeds after flowering above‐ground, subterranean vetch flowers and forms pods beneath the soil surface on underground stems. The aerial pods are produced after vegetative development ceases, while the underground pods are produced in ontogeny. The ability of this unusual vetch to survive in marginal areas with low rainfall (about 250 mm year?1) and to produce nutritious herbage and pods is an important characteristic which helps address rehabilitation of degraded rangelands and increase feed production for small ruminants. Research at the International Center for Agricultural Research in the Dry Areas (ICARDA) during the 1988–93 growing seasons has assessed the herbage and seed productivity of underground vetch, its ability to grow in rotation with barley in marginal low‐rainfall areas, and its capacity to regenerate after heavy grazing. Drier conditions in 1989 favoured earlier underground flowering; the number of underground pods was higher than that of aerial pods. Grain yield of barley (var. Atlas) was around 2.0 t ha?1 after underground vetch and only 1.2 t ha?1 after barley. Grazing underground vetch had no effect on the productivity of the succeeding barley crop. The aerial and underground pods serve two distinct functions; aerial pods increase dissemination within suitable habitats, while underground pods increase the probability of plant survival under adverse conditions such as drought and heavy grazing. Underground vetch has two potential uses, namely the rehabilitation of marginal areas and production in rotation with barley.  相似文献   
89.
Tropical Animal Health and Production - This study aimed at investigating the relationship between concentrations of macro and trace elements in blood serum, and fluids from small and large...  相似文献   
90.
The present study was carried out to explore the impacts of dietary supplementation of enzyme mixture with sodium butyrate on the growth performance, carcass traits, blood profile and economic benefit in two breeds of weanling rabbits adapted to survive in Egypt (New Zealand White and Rex). One-hundred and twenty weaned male rabbits (New Zealand White and Rex) of 6 weeks of age and 770.5 ± 20 g body weight were allotted randomly into four groups in a factorial arrangement. The obtained results indicated that there were non-significant differences in all growth performance traits, blood profile and economic parameters due to the breed effect. However, there were significant differences in most of carcass traits due to the breed effect except total giblets and New Zealand White breed showed the highest value of these parameters including dressing % (p < .01), forequarter and loin % (p < .001) and hindquarter % (p < .003) compared with Rex breed counterparts. The effect of the treatment and its interaction with the breed significantly (p < .05) improved body weight gain, feed consumption and carcass traits (percentage of dressing, forequarter, hind quarter and lion). However, final body weight and feed conversion ratio were not significantly influenced. Supplementing a diet with treatment significantly decreased blood triglycerides, cholesterol and the ratio between albumin and globulin (A/G ratio), while increased blood total protein and globulin. Although higher feed cost and total costs in treated groups than control ones in each breed, they showed higher total return and net return. Rex non-treated rabbit breed showed the lowest profitability measures compared with other groups. In conclusion, dietary supplementation of multi-enzyme with sodium butyrate is highly recommended in growing rabbits due to their beneficial effects on the growth performance and profitability.  相似文献   
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