The survey of wild birds for West Nile virus in Poland

Two thousand one hundred and forty birds belonging to 39 different species from different locations in Poland were examined. The study has taken place from the early spring till late autumn 2007-2010 when the activity of the mosquitoes was the highest. The brain samples were taken from the birds and whole cellular RNA was isolated, then the RT-PCR and NRT-PCR were performed to detect the presence of West Nile virus (WNV). The obtained results were confirmed by the commercial WNV Kit. No genetic material of WNV was found in the examined samples.     

The effect of feed quality on the kinetic disposition of orally administered triclabendazole in sheep

The effect of two qualities of feed on the kinetic disposition of triclabendazole (TCBZ) metabolites was investigated in sheep (n = 4) following oral administration of TCBZ at 10 mg/kg body weight. The same sheep were given sequentially two qualitatively different diets: a low-quality (LQ) diet based on wheat straw ad libitum, and a high-quality (HQ) diet based on barley+alfalfa. The triclabendazole sulphoxide (TCBZSO) and triclabendazole sulphone (TCBZSO₂) concentrations were determined in blood samples taken serially from the jugular vein between 5 min and 9 days after TCBZ administration. The parent drug TCBZ was not detected in any of the samples. The quality of feed affected the kinetics of both TCBZ metabolites. The rate of appearance (T_lag and T_max) in the jugular blood was slower and the formed amount (AUC) of TCBZSO was slightly higher when the sheep were on the LQ diet (T_lag = 7.74 h; T_max = 27.91 h; AUC = 1042 g.h/ml) than when they were offered the HQ diet (T_lag = 1.90 h; T_max = 16.01 h; AUC = 832.4 g.h/ml). The MRT of TCBZSO was about 40% longer with the LQ diet than with the HQ diet. Similarly, the rate of appearance of TCBZSO₂ in plasma of sheep was slower when they were on the LQ diet than when they were on the HQ diet, suggesting an impairment of the hepatic enzymatic activity involved in the oxidation of TCBZSO to TCBZSO₂.     

树木抗旱性及抗旱造林技术研究综述

文中阐述了国内外在树木抗旱性、树木抗旱性机理、抗旱树种选育以及节水抗旱造林技术等方面的研究成果与进展,同时对我国抗旱造林提出了自己的见解。     

Gonadal function, sexual behavior, feedlot performance, and carcass traits of ram lambs actively immunized against GnRH

The effect of active immunization against GnRH on production, carcass, and behavioral traits was examined in ram lambs fed to a uniform slaughter weight. Lambs (initial BW = 32.6+/-1 kg) were stratified by BW and assigned at random to one of four treatment groups (n = 12 lambs/group). Lambs were untreated, castrated, or actively immunized against GnRH using a GnRH-keyhole limpet hemocyanin conjugate (1 mg) emulsified with either Freund's complete adjuvant (FCA) or another oil-based adjuvant (ISA). Animals were housed individually and slaughtered at 58 kg BW. Immunoneutralization of GnRH reduced (P < .05) testes weight and the concentration of testosterone in serum at slaughter. Suppression of testicular size and function was most clearly evident in animals immunized using FCA. Final anti-GnRH titer was also highest in lambs immunized using FCA. Several measures of sexual behavior (frequency of mounts and ejaculations) were also reduced (P < .05) in animals immunized using FCA. The duration of the feeding period was greater (P < .05) for castrated lambs than for untreated lambs, and intermediate feeding periods were required for FCA and ISA lambs. Average daily gain was greater (P < .05) in untreated than in castrated, FCA, or ISA lambs. Similarly, feed efficiency for untreated lambs was greater (P < .05) than for castrated, FCA, or ISA lambs, but feed efficiency did not differ among castrated, FCA, or ISA lambs. Longissimus muscle area, lean and bone maturity, overall quality, muscling score, flank streaking, and color of fat did not differ among treatments. Intact, FCA, and ISA lambs had more (P < .05) desirable yield grades, less (P < .05) backfat, and less (P < .05) marbling than castrated lambs. In summary, immunization against GnRH decreased testicular weight and reduced (P < .05) feedlot performance and sexual behavior to levels comparable to those of castrated males. Partitioning of nutrients for growth and deposition of fat, however, seems to differ among immunologically castrated and physically castrated lambs. This difference in nutrient partitioning may be due to residual testicular activity in immunized lambs.     

加强家禽疫情监测保障产业健康发展

家禽产业的发展离不开生物安全措施的保障,其中对疫情的监测十分重要,不仅影响家禽的生产性能,而且关系到产业的健康发展。作者以禽流感的监测为例,为家禽疫病的监测提供了良好的指导和借鉴。     

影响麦二叉蚜传播玉米矮花叶病毒效率的因素分析

玉米矮花叶病毒（ＭＤＭＶ）在田间主要依靠介质蚜虫非持久性方式传播,通过麦二叉蚜（Ｓｃｈｉｚａｐｈｉｓｇｒａｍｉｎｕｍ）对ＭＤＭＶ传毒效率影响因素的分析,发现接毒蚜获毒前禁食与否及禁食时间的长短与传毒效率呈高度正相关,从蚜量与传毒效率的关系来看,多头蚜虫的传毒效率均比单头蚜高,随着ＭＤＭＶ浓度和传毒蚜量的增加,传毒效率也随之提高,单蚜获毒１０ｍｉｎ后不禁食其传毒效率最高,随着禁食时间的延长,其传毒效     

Muscarinic receptor subtypes in equine tracheal smooth muscle

Selective muscarinic receptor antagonists were used to identify muscarinic receptor subtypes in equine trachealis strips. The M₁ receptor antagonist pirenzepine (10^–7 mol/L to 3 × 10^–5 mol/L) and the M₃ receptor antagonist 4-diphenylacetoxy-N-methylpiperidine (4-DAMP, 10^–9 mol/L to 3 × 10^–7 mol/L³) dose dependently inhibited the contractile responses to electrical field stimulation (EFS) and exogenous acetylcholine (ACh). Schild plots yielded a pA₂ value for pirenzepine vs ACh of 6.75 ± 0.09, which is consistent with the affinity for M₂ or M₃ receptors, and a pA₂ value for 4-DAMP vs ACh of 8.47 ± 0.09, which is in agreement with the affinity for M₃ receptors. The M₂ receptor antagonist gallamine (10^–5 mol/L and 10^–4 mol/L) did not affect the response of trachealis to exogenous ACh and low-frequency EFS (0.1–2 Hz) but decreased the responses to high-frequency EFS (4–16 Hz). These results suggest that the muscarinic receptors mediating contractions induced by ACh in equine tracheal smooth muscle are of the M₃ subtype. The lack of an increase in the response to EFS following gallamine suggests that functional prejunctional inhibitory M₂ receptors are not present on the cholinergic nerves innervating equine tracheal smooth muscle.     

Cell lines from sheep and cattle blood

A simple and reproducible method of establishing cell lines from the blood of sheep and cattle is described. Buffy coat cells were allowed to adhere to plastic culture flasks in media containing 20 per cent autologous plasma overnight. The fluids were then replaced with growth medium supplemented with non-inactivated foetal calf serum, lamb serum or autologous serum. Ovine cell lines were established with any of the serum supplements but bovine cell lines were established more readily if unheated autologous serum was used.     

水稻普通矮缩病毒致病力分化的初步探索

 水稻病毒病抗性育种工作在国外已进行了十余年,取得了显著成效,但对病毒致病力的分化问题却研究得不多。