1. The effect of supplementing grower diets with bicarbonate or chloride on haematological variables, pulmonary hypertension syndrome and ascites in broilers exposed to cold temperature was investigated. 2. High concentrations of dietary chloride had no effect on the pH of the venous blood but a low chloride/high bicarbonate diet significantly increased blood pH. There was no consistent effect of dietary chloride or bicarbonate concentrations on growth performance, although in 1 experiment birds given a low chloride/high bicarbonate diet consumed less food and gained less weight than controls. 3. Birds fed on high-chloride diets tended to have a higher incidence of ascites and pulmonary hypertension than controls. Birds fed on low-chloride and high-bicarbonate diets had significantly lower pulmonary hypertension and lower heart weights, which may have indicated a decrease in pulmonary and systemic blood pressure. 4. We conclude that increasing dietary bicarbonate and reducing dietary chloride has potential as a low cost and effective method to reduce the pulmonary hypertension which leads to ascites in broiler chickens. 相似文献
The purpose of this study was to determine the rate of decline and geographical distribution by municipality of clinical and subclinical African swine fever (ASF) in the affected areas of Spain. A second aim was to evaluate the performance of diagnostic tests in the Spanish ASF eradication program. Clinical outbreaks were confirmed using both the direct and indirect immunofluorescence test (and if both were negative, by the hemabsorption test). The serological status of swine was determined by an enzyme-linked immunosorbent assay (ELISA) and suspect serum samples were confirmed by the immunoblot assay.
The number of clinical outbreaks (herds) of ASF for 1989, 1990 and 1991 was 170, 347 and 207, respectively. The numbers of municipalities within each affected province experiencing acute outbreaks for the same time periods were 49, 69 and 48, respectively. Serologically diagnosed animals positive for ASF were 1.1% of animals tested in 1989, 0.5% in 1990 and 0.8% in 1991. The corresponding positive predictive values of the standard ELISA test used were 99.0, 97.9 and 98.8, respectively. Similarly, the number of municipalities within each affected province experiencing serologically positive subclinically infected animals was 269, 178 and 147 for each of the years 1989, 1990 and 1991, respectively. 相似文献
A diagnosis of toxic necrotizing cholangiohepatitis was made in approximately 35% of a flock of 23,000 commercial broiler chickens. Affected chickens were small, and had discrete green foci throughout the liver. Seven to twelve days prior to shipping the flock to slaughter, premixes containing oxytetracycline, monensin, and 3-nitro-4-hydroxyphenylarsonic acid had been added to the ration because the birds had wet droppings and were growing slowly. The 3-nitro-4-hydroxyphenylarsonic acid had been inadvertently incorporated at ten times the recommended level. Liver and kidney of affected birds had elevated levels of total arsenic, and special strains demonstrated arsenic in necrotic foci in liver. Histologically there was marked dilation of intrahepatic bile ducts, and patchy necrosis and hyperplasia of the bile duct epithelium. Damage to bile ducts may have been a toxic manifestation of altered metabolism and excretion of the three drugs being fed to birds suffering from intercurrent diarrhea and/or undefined interactions among the drugs. 相似文献
Caprine β-mannosidosis, a fatal inherited deficiency of the lysosomal enzyme β-mannosidase, was diagnosed in neonatal female Nubian crossbred twin kids from a small herd near Guelph, Ontario. The kids had been tetraplegic since birth, with whole body tremors, abnormal nystagmus and an intention tremor of the head. 相似文献
Based on recent needs to accurately understand fire regimes and post-fire vegetation resilience at a supra-level for carbon cycle studies, this article focusses on the coupled history of fire and vegetation pattern for 40 years on a fire-prone area in central Corsica (France). This area has been submitted since the beginning of the 20th century to land abandonment and the remaining land management has been largely controlled by frequent fires. Our objectives were to rebuild vegetation and fire maps in order to determine the factors which have driven the spatial and temporal distribution of fires on the area, what were the feed backs on the vegetation dynamics, and the long-term consequences of this inter-relationship. The results show a stable but high frequency of small fires, coupled with forest expansion over the study period. The results particularly illustrate the spatial distribution of fires according to topography and vegetation, leading to a strong contrast between areas never burnt and areas which have been burnt up to 7 times. Fires, when occuring, affect on average 9 to 12% of the S, SE and SW facing slopes (compared to only 2 to 5% for the N facing slopes), spread recurrently over ridge tops, affect all the vegetation types but reburn preferentially shrublands and grasslands. As these fire-proning parameters have also been shown to decrease the regeneration capacity of forests, this study highlights the needs in spatial studies (both in terms of fire spread and vegetation dynamic) to accurately apprehend vegetation dynamic and functionning in fire-prone areas.This revised version was published online in May 2005 with corrections to the Cover Date. 相似文献
Flowering time is the most critical developmental stage in wheat, as it determines environmental conditions during grain filling. Thirty-five spring durum genotypes carrying all known allele variants at Ppd-1 loci were evaluated in fully irrigated field experiments for three years at latitudes of 41°N (Spain), 27°N (northern Mexico) and 19°N (southern Mexico). Relationships between weight of central grains of main spikes (W) and thermal time from flowering to maturity were described by a logistic equation. Differences in flowering time between the allele combination causing the earliest (GS100/Ppd-B1a) and the latest (Ppd-A1b/Ppd-B1a) flowering were 7, 20 and 18 days in Spain, northern Mexico and southern Mexico, respectively. Flowering delay drastically reduced the mean grain filling rate (R) and W at all sites. At autumn-sowing sites, an increase of 1°C in mean temperature during the first half of the grain filling period decreased W by 5.2 mg per grain. At these sites, W was strongly dependent on R. At the spring-sowing site (southern Mexico), W depended on both R and grain filling duration. Our results suggest that incorporating the allele combinations GS100/Ppd-B1a and GS105/Ppd-B1a (alleles conferring photoperiod insensitivity) in newly released varieties can reduce the negative effects of climate change on grain filling at the studied latitudes. 相似文献
Plant Foods for Human Nutrition - ADP-glucose pyrophosphorylase (AGPase) is a key enzyme of starch synthesis in seeds, tubers and fruits. UDP-glucose pyrophosphorylase (UGPase) is an important... 相似文献
Soybean aphid (Aphis glycines Matsumura) has become one of the major pests of soybean [Glycine max (L.) Merr.] in North America since 2000. At least four biotypes of soybean aphid have been confirmed in the United States. Genetic characterization of new sources of soybean aphid resistance will facilitate the expansion of soybean gene pool for soybean aphid resistance and thus will help to develop soybean aphid resistant cultivars. To characterize the genetic basis of soybean aphid resistance in PI 603712, a newly identified resistant germplasm line, 142 F2 plants derived from the cross ‘Roberts’ × PI 603712 and their parents were evaluated for soybean aphid resistance in the greenhouse, and were genotyped with BARCSoySNP6K Illumina Infinium II BeadChip. A genome-wide molecular linkage map was constructed with 1495 polymorphic SNP markers. QTL analysis revealed that PI 603712 possessed two major loci associated with soybean aphid resistance, located on chromosome 7 and 16, respectively. The locus on chromosome 7 was dominantly expressed and positioned about one Mega-base-pair distant from the previously identified resistance locus Rag1. The locus on chromosome 16 was positioned near the previously identified resistance locus Rag3 and expressed partially dominance or additive effect. Interestingly, two minor loci were also detected on chromosomes 13 and 17 but the alleles from PI 603712 decreased the resistance. In developing soybean aphid resistant cultivars through marker-assisted selection, an appropriate combination of resistance loci should be selected when PI 603712 is used as a donor parent of resistance. 相似文献