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排序方式: 共有106条查询结果,搜索用时 15 毫秒
81.
Essén-Gustavsson B Jensen-Waern M Jonasson R Andersson L 《American journal of veterinary research》2005,66(7):1197-1201
OBJECTIVE: To investigate influence of the Rendement Napole (RN-) mutation on proglycogen (PG) and macroglycogen (MG) content in skeletal muscles before and after exercise and evaluate glycogen concentrations within various muscle fiber types. ANIMALS: 5 pigs with the RN- mutation and 3 noncarrier pigs. PROCEDURE: Pigs performed 2 exercise tests on a treadmill. In the first, pigs (mean body weight, 27 kg) ran a distance of approximately 800 m. In the second, pigs (mean body weight, 63 kg) ran until fatigued. Biopsy specimens (biceps femoris muscle) for determination of PG and MG contents were obtained before and after exercise, 24 hours after the first test, and 3 hours after the second test. Histochemical analysis was performed on specimens obtained before and after the second test. RESULTS: Before exercise, PG stores did not differ markedly between groups, but MG stores were twice as high in pigs with the RN- mutation, compared with noncarrier pigs. The MG content decreased to a similar extent in both groups after exercise. Resynthesis of MG was greater in pigs with the RN- mutation than in noncarrier pigs by 3 hours after exercise. A low glycogen content after exercise was observed in many type I and type IIA fibers and in some type lIB fibers. CONCLUSIONS AND CLINICAL RELEVANCE: The RN- mutation was associated with high MG stores in skeletal muscle that did not influence exercise performance. The RN- mutation did not impair glycogenolysis during exercise but may induce faster resynthesis of MG after exercise. 相似文献
82.
Birgitta Malm?Ren?f?ltEmail author Roland?Jansson Christer?Nilsson 《Landscape Ecology》2005,20(2):165-176
Analysis of landscape-scale patterns of plant invasiveness can assist in interpreting spatial patterns of plant species richness. We investigated downstream variation in plant invasiveness in the riparian corridor of the free-flowing Vindel River in northern Sweden by introducing seeds of an alien species, Helianthus annuus, in 0.25 m2 plots of natural vegetation from mountain headwaters to the coast and found a significant downstream pattern with middle reaches having the highest invasiveness. We related invasiveness to species richness, both on a reach scale (200-m long stretches of riverbank encompassing the experimental plots) and on the scale of experimental plots. We found no significant correlation between plant invasiveness and species richness, neither at the reach nor at the plot scale. The number of available soil substrates shows a significant positive quadratic relationship with location along the river and substrate fineness shows a near significant negative quadratic relationship with location along the river, with middle reaches having coarser substrates. Several studies have shown that plant species richness in riparian corridors often exhibits a quadratic pattern with highest species richness in the middle reaches of a river, similar to the pattern we found for invasiveness. Although species richness per se might not be a primary factor for invasibility, the same habitat conditions as those supporting plant species richness, can help in explaining large-scale patterns of plant invasion in riparian zones. 相似文献
83.
A total of 103 Danish Haemophilus parasuis field isolates was collected from diseased pigs in connection with routine diagnostics. The isolates were serotyped using indirect haemagglutination (IHA) and for 57 of the isolates the serotyping was also performed by immunodiffusion. Serovar 5 was the most prevalent (36%), followed by serovar 4 (13%) and serovar 13 (22%), whereas 15% of the strains were nontypeable by IHA. Serovars 1, 2, 6, 7, 9, 12, 14, and 15 were only represented by a small number of isolates. Most of the Danish isolates belong to serovars, which earlier have been shown to be virulent. The strains could be divided into two groups depending on whether they were isolated from cases with systemic disease (polyserositis, arthritis or meningitis) or if they only were found in the lower respiratory tract. The most marked differences were observed for serovar 4, which had a higher prevalence in respiratory disease compared to systemic infection, and for the nontypeable isolates, which were mainly found in cases of systemic infection. 相似文献
84.
The aim of the study was to test the performance of a silver wire modified version of the coded telemetric heart rate monitor Polar Vantage NV (PVNV) and to measure heart rate (HR) in a group of captive reindeer calves during different behaviour. The technical performance of PVNV HR monitors was tested in cold conditions (-30 degrees C) using a pulse generator and the correlation between generated pulse and PVNV values was high (r=0.9957). The accuracy was tested by comparing the HR obtained with the PVNV monitor with the standard ECG, and the correlation was significant (r=0.9965). Both circadian HR and HR related to behavioural pattern were recorded. A circadian rhythm was observed in the HR in reindeer with a minimum during night and early morning hours and maximum at noon and during the afternoon, the average HR of the reindeer calves studied being 42.5 beats/min in February. The behaviour was recorded by focal individual observations and the data was synchronized with the output of the HR monitors. Running differed from all other behavioural categories in HR. Inter-individual differences were seen expressing individual responses to external and internal stimuli. The silver wire modified Polar Vantage NV provides a suitable and reliable tool for measuring heart rate in reindeer, also in natural conditions. 相似文献
85.
The objective of this study was to analyze the development of inbreeding and estimate inbreeding depression in the Danish populations of 3 major meat type sheep breeds. The pedigrees contained 29,336 Texel, 22,838 Shropshire, and 11,487 Oxford Down. The rate of inbreeding was approximately 1% per generation for all breeds, but the rate of increase in co-ancestry was somewhat lower (0.45 to 0.71), indicating that more inbreeding has been accumulating than would be expected if mating was at random. Inbreeding depression for birth weight, ADG from birth until 2 mo, and litter size was estimated for all 3 breeds using a minimum of 15,000 records per trait and breed. All traits showed depression due to inbreeding of the animal itself. For most combinations of trait and breed, there was also a significant reduction of the phenotype due to inbreeding in the dam. The size of inbreeding depression was 1.2 to 2.6% of the mean, resulting in an increase in the inbreeding coefficient of the individual of 0.10, and estimates were similar for similar increases in maternal inbreeding. The rate of inbreeding in these breeds needs to be reduced in the future to avoid a further decline in birth weight, ADG, and litter size. 相似文献
86.
J. Norberg 《Aquaculture Research》1999,30(6):427-430
In aquaculture, the benefit of autotrophic production within land-based ponds for fish production has long been recognized. In cage culture, organisms growing on the cage net have so far only been considered as a problem. This study investigated the potential production of periphyton on cage nets used in a tropical mixed tilapia culture of Oreochromis mortimeri (Trewavas), Tilapia rendalli (Boulenger) and Oreochromis niloticus (Linnaeus) in Lake Kariba, Zimbabwe. The production of periphyton was assessed experimentally and compared with the energy demand of the caged fish. The tilapias were found to graze intensively on the net, and the primary production of periphyton on the cage net was ≈ 1% relative to the energy demands of the fish. 相似文献
87.
Albert K Imsland Henriette Hanssen Atle Foss Erik Vikingstad Bjørn Roth Marit Bjørnevik Mark Powell Christel Solberg Birgitta Norberg 《Aquaculture Research》2013,44(11):1665-1676
Atlantic cod Gadus morhua L. (initial weight 130 g, final weight 2800 g) was exposed to continuous light at different stages during the production cycle, and the effect on growth performance, age at first maturation, plasma sex steroid levels and flesh quality were investigated. The entire photoperiod experiment was divided into five phases where the fish in each phase were exposed to either natural photoperiod (N, 65°28′) or continuous light (C). Thus, the following five photoperiod combinations were tested: (a) control group (NNNNN), (b) group 2A (NCNNN), (c) group 2B (NNCNN), (d) group 2C (NNNCN) and (e) continuous light group (CCCCC). Short‐term exposure to continuous light in the first (group 2A) and second (group 2B) growth phases stimulated growth, as the final mean weights of groups 2A and 2B were 11% and 19% higher than those of the control group (NNNNN). Growth in the control group and group 2C was arrested from January to May in the second year. Continuous light (CCCCC) stimulated growth at the beginning of the trial, but the effect diminished at the end. Reduced male plasma 11‐ketotestosterone (11‐KT) and female estradiol 17β (E2) levels were found in groups 2A and 2B and continuous light group, as compared with the control group and group 2C at 26 months post hatch, indicating a higher age at first maturation in these groups. The 11‐KT and E2 levels increased in May–June in group 2A indicating that first maturation was postponed by 6 months in this group, whereas first maturation was postponed by 1 year in group 2B and in the continuous light group. Photoperiod regime only had minor effects on flesh quality traits of the fish. 相似文献
88.
89.
Lena Andersson-Eklund Birgitta Danell Jan Rendel 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(2):87-95
Abstract The relationships between 12 polymorphic systems and bull fertility were studied in the Swedish Red and White dairy cattle population. The material consisted of 1447 young bulls with non-return rates based on at least 500 inseminations each. A reduced animal model including a full additive relationship matrix was used. Multiple regressions were fitted for the estimation of the average gene substitution effects as well as the gene-frequency-independent effects of additive gene action and dominance. To evaluate the results a multivariate analysis of variance, classical segregation analyses and marker frequency studies were performed. Significant associations were found between the F, B, Tf, S and C systems, and nonreturn rates, but the contribution of the markers to the total variation of non-return rates was small. 相似文献
90.
Abstract Genetic parameters for protein yield, clinical mastitis, SCS, number of inseminations (NI), and days from first to last insemination (FLI) were estimated for first-parity Danish Holstein cows. The objective was to estimate genetic correlations between the five traits mentioned above and to study whether NI and FLI are measures of the same trait. Records containing information on approximately 200 000 cows were analysed using tri-variate animal models. The genetic correlations between the udder health traits and the fertility traits were favourable and in the range from 0.17 to 0.42, whereas the genetic correlations between protein yield and the fertility traits were unfavourable and ranged from 0.43 to 0.52. These results highlight the importance of continuing to emphasize functional traits in future breeding programmes. The genetic correlation between the fertility traits was 0.82. Based on this result, it cannot be concluded that NI and FLI are measures of the same trait. 相似文献