Lactobacilli counts in crop,ileum and caecum of growing broiler chickens fed on practical diets containing whole or dehulled sweet lupin (Lupinus angustifolius) seed meal

1. Four experiments with growing broiler chickens were carried out to study the effects of the inclusion in their diets of lupin (Lupinus angustifolius ) seed meal on E. coli and lactobacilli counts in crop, ileum and caeca at 3 or 4 weeks of age. 2. Diets were formulated to contain the same amounts of metabolisable energy (12.55 MJ/kg) and protein (210 g/kg). Raw whole (heat-untreated) or dehulled sweet (low in alkaloids) lupin seed meal (400 and 320 g/kg respectively) were used to prepare the lupin-based diets, whose protein content was completed with either defatted soyabean meal or casein. 3. Final body weight and food intake of chickens fed on whole lupin seed meal diets were lower than controls, but gain: food ratios were not different. However, birds given the diet with dehulled lupin seed meal had similar body weight, food intake and gain: food values as those of controls. 4. While E. coli counts were not affected, lactobacilli numbers were consistently increased compared to controls in all intestinal sections of chickens fed on the whole or dehulled lupin-based diets, irrespective of the age of the birds or the presence of soyabean meal or casein in the diet. The lactobacilli species isolated were: Lactobacillus fermentum, L. acidophilus, L. salivarius and L. brevis 5. The results suggest that the use of whole or dehulled sweet lupin seed meal in diets for growing broilers might enhance the growth of lactic acid-fermenting bacteria in the gut.     

Utilisation de souches non pathogènes de Fusarium pour lutter contre les fusarioses: situation actuelle dans la pratique1

Des travaux antérieurs ayant permis de démontrer que des souches non pathogènes de Fusarium sont impliquèes dans les mécanismes de résistance des sols aux fusarioses, nous avons tenté d'utiliser des souches de Fusarium sélectionnées pour lutter contre ces maladies. Les bons résultats obtenus en conditions expérimentales nous ont conduits à mettre en place un réseau d'expérimentation en conditions normales de culture dans des serres de production de tomates et de melons. Le premier problème à résoudre est celui de la production massive d'inoculum, de sa conservation et de son introduction dans les sols et substrats de cultures. La production de l'inoculum est réalisée en fermenteur, les propagules produites soni récupérées par filtration et mélangées avec du talc, support inerte qui après avoir été séché assure la conservation et la distribution de cet inoculum dans des conditions satisfaisantes. Les quantités d'inoculum produites en 1985–86 ont permis de réaliser plusieurs essais de lutte dans des conditions normales de production. L'inoculum protecteur est apporté, soit dans les substrats de culture hors sol au moment de leur ensachage, soit dans les sols en place, immédiatement après leur désinfection au bromure de méthyle. L'installation de la souche protectrice est suivie régulièrement grace à des analyses microbiologiques et la gravité de la maladie est notée régulièrement en cours de culture. Les résultats enregistrés en 1986, variables d'une situation à l'autre, ne permettent pas de porter un jugement définif sur l'intéret de ce procédé de lutte. Ils sont cependant intéressants et permettent d'organiser sur des bases plus solides notre campagne d'expérimentation 1986–87.     

奶牛温氏支原体16SrRNA基因的PCR扩增、克隆及分析

目的对奶牛温氏支原体16SrRNA基因进行PCR扩增及克隆分析。方法从自然感染体的广西奶牛无菌采集血液,分离温氏支原体并提取病原基因组,用血营养菌的16SrRNA基因的通用引物进行PCR扩增,将扩增产物克隆到PGEM-Teasy载体后进行溺,I序和分析,并与Genebank上搜索的温氏支原体相应序列进行比较,建立系统发育树。结果PCR扩增得到长约1．5kb的扩增片段,测序结果显示该片段全长为1453bp,同源性分析表明该序列与Neimark公布的温氏支原体（前称温氏附红细胞体）（AF016546）的16SrRNA基因序列同源性达到97．4％,与系统发育进化树表明本株温氏支原体同本地株的关系较近,而与国外株的新缘关系较远。国内公布的广西株同源性为99．8％。结论结果表明证实该病原为温氏支原体,从分子生物学水平证实了温氏支原体在广西的存在。由于本试验分离得到的牛温氏支原体与国外发表的牛温氏支原体核苷酸序列相差2．6％,因此两者的基因型存在一定的差异,这对该病的分子流行病学分析具有一定的意义。     

四种基质对大根报春苣苔叶插繁殖的影响

为探明不同基质对大根报春苣苔(Primulina macrorhiza)叶插繁殖的影响,以大根报春苣苔的全叶片为试验材料,采用正交试验设计,研究泥炭、珍珠岩、蛭石、稻壳炭4种基质对叶片扦插成活率、子株数、新叶总数的影响,并筛选出最优组合。结果表明,在试验的9个处理中,扦插基质以泥炭∶珍珠岩∶蛭石∶稻壳炭为4∶2∶2∶1(体积比)为佳。泥炭对成活率、子株数、新叶总数均有显著影响(P0.05);珍珠岩对成活率、子株数、新叶总数均无显著影响(P0.05);蛭石仅对新叶总数有显著影响(P0.05);稻壳炭仅对子株数有显著影响(P0.05)。正交分析并推理出,以4种成分为扦插基质时,泥炭、珍珠岩、蛭石和稻壳炭的最佳配比为2∶1∶1∶1(体积比)。     

Distribution of infectious pancreatic necrosis virus (IPNV) in wild marine fish from Scottish waters with respect to clinically infected aquaculture sites producing Atlantic salmon, Salmo salar L

This study represents the first large-scale investigation of IPNV in Scottish wild marine fish. Kidney samples were taken from 30 627 fish comprising 37 species and 45 isolations were made from nine different species, illustrating these as reservoirs of IPNV in Scottish waters. The estimated prevalence of IPNV in the Scottish marine environment was low at 0.15% (90% confidence intervals, (CI) of 0.11-0.19%). This was significantly greater in fish caught less than 5.0 km from IPN-positive fish farms in Shetland, at 0.58% (90% CI of 0.45-0.77%). This prevalence persisted and did not significantly decrease over the 16-month period of study. The estimated prevalence of IPNV for each positive species was less than 1% with the statistically non-significant exceptions of flounder, Platichthys flesus (L.), at 12.5% (90% CI of 0.64-47.06%) and saithe, Pollachius virens (L.), at 1.11% (90% CI of 0.49-2.19%). The 45 isolates were titrated and all but two were below the detection limit of the test (<55 PFU g(-1)). Titres of 3.8 x 10(2) PFU g(-1) and 2.8 x 10(1) PFU g(-1) were calculated from common dab, Limanda limanda (L.), and saithe, respectively. This study provides evidence that clinical outbreaks of IPN in farmed Atlantic salmon may cause a localized small increase in the prevalence of IPNV in wild marine fish.     

临夏州不同种植区马铃薯播种适期研究

临夏州马铃薯种植区域主要分布在无灌溉条件,年降雨量不足200 mm的干旱山地和年降雨量约600 mm的山二阴地,以及灌溉便利,年降雨量在500 mm左右的川塬区。通过种植区域、播种时间和栽培措施3因素对比试验,以产量、病害损失和经济效益做综合分析对比,得出临夏州春旱较频繁的干旱山地和山二阴地区应适当推迟播期至5月上旬左...     

A comparison between non-destructive and destructive testing of Atlantic salmon, Salmo salar L., broodfish for IPNV--destructive testing is still the best at time of maturation.

Two populations of Atlantic salmon broodstock, previously identified as infectious pancreatic necrosis virus (IPNV) carriers, were screened for IPNV at the time of stripping. Four hundred and ten broodfish were individually sampled of which 91 were detected as IPNV positive by virus culture of sonicated kidney homogenates combined with gonadal fluid, but none tested positive by the blood leucocyte assay. Thirty fish identified as IPNV carriers prior to maturation by the blood leucocyte assay were used in a separate study to compare non-destructive vs. destructive testing methods at stripping. IPNV was not detected using the blood leucocyte method at the time of stripping. RT-PCR and real-time PCR assays failed to detect IPNV from 13 blood samples, the virus was not isolated from milt (0/14) or sonicated ovarian fluid cell pellets (0/16) and only three fish tested positive by the standard culture of kidney homogenates. A third study of Atlantic salmon broodfish compared the IPNV isolation rates prior to maturation with the isolation rates at spawning during 1999-2001. In each year the percentage of IPNV-positive broodfish was significantly lower than in the pre-broodstock sample. While in pre-broodfish samples IPNV was detected by the blood leucocyte assay, no culture isolations or PCR positives were detected from non-destructive samples of the same individual broodfish at stripping. A consistent finding was that even for the kidney assay, the percentage of IPNV-positive fish in carrier populations was higher in pre-broodstock than in broodfish at stripping. These results indicate that destructive kidney sampling is still the most sensitive method for detecting IPNV carrier Atlantic salmon broodfish and that a change in IPNV carrier-status occurs during the maturation period.     

In infectious pancreatic necrosis virus carrier Atlantic salmon, Salmo salar L., post-smolts, almost all kidney macrophages ex vivo contain a low level of non-replicating virus

The level of infection by infectious pancreatic necrosis virus (IPNV) of kidney macrophages from 12 asymptomatic carrier Atlantic salmon post-smolts was studied. Kidney leucocytes were fractionated on 34/51% Percoll gradients, allowed to adhere to plastic wells overnight, washed to remove non-adherent cells and cultured for up to 7 days with or without renewal of medium on day 3. On day 1, supernatants were harvested, macrophages were counted, lysed and IPNV in the supernatants and lysates was titred in chinook salmon embryo (CHSE-214) cells. The multiplicity of infection ranged between 1:2.2 and 1:7.4 (virus:macrophages). On day 3, the titres of IPNV in macrophage lysates decreased and in wells where the medium was renewed on day 3, IPNV was no longer detectable on day 7. In the supernatants, one fish was positive for IPNV on day 1, four fish on day 3 but none were detectably positive on day 7. In parallel wells in which the medium was not renewed, on day 7 IPNV was detected in macrophage lysates of three fish and the supernatants were also IPNV positive in two of these fish. This suggests that virus might be shed from infected macrophages and then reinfect other macrophages. When macrophages were serially diluted in wells and cultured for 24 h, IPNV could be cultured from macrophage lysates of wells containing between two and 70 macrophages. These results indicate that a very high proportion of the adherent kidney macrophages must be infected with very few non-replicating virions.