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71.
Rikke Fink Christian Friis Børsting 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2013,63(1):34-42
Glucose metabolism was measured during two consecutive years, 4 weeks postpartum, in a total of 36 yearling female mink, fitted with jugular vein catheters and raising litters of six to seven kits. The dams were fed ad libitum from parturition on diets with different ratios of metabolizable energy (ME) derived from protein:fat:carbohydrates (experiment 1: 61:37:2, 46:37:17, 31:37:32; experiment 2: 61:38:1, 47:52:1, 33:66:1). After 3 h fasting the dams were fed 210 kJ ME of the experimental diets. Two hours postprandially a single dose of 50 w Ci U- 14 C- and 2- 3 H-labelled glucose was administered to each dam and blood samples were drawn 5, 10, 20, 30, 45 and 60 min after the tracer administration. Glucose turnover rates were 4-5% min -1 in all dams, and the approximate daily glucose flux was 12-17 g day -1 ; however, these were not significantly affected by dietary treatment. In conclusion, the mink is able both to synthesize large amounts of glucose de novo and to utilize high levels of dietary digestible carbohydrates, and thereby to tolerate large variations in dietary carbohydrate supply. 相似文献
72.
Poul Hansen 《The Journal of Horticultural Science and Biotechnology》2013,88(3):211-216
One-year-old ‘Cox’s Orange Pippin’ trees planted in pots in sand culture in the spring of 1970 were (during the growing seasons of 1970–72) watered with nutrient solutions containing 0, 0.12, 0.23, 1.2, 3.5 or 7.0 mg boron per litre.With increasing boron supply, the boron concentration of the leaves increased, the growth of current year’s shoots and to some extent of other plant parts increased, and summer leaf-fall and the occurrence of necrotic leaf spots (‘Cox spots’) decreased. The percentage of healthy leaves was greatest when boron in leaf dry matter was about 30 ppm.In 1972 the trees with highest boron supply suffered from incipient boron toxicity and increased incidence of ‘Cox disease’ flowering was delayed, and the percentage of dead buds was increased. In the latter part of the summer the leaves curled upwards, turned purple and became brittle. 相似文献
73.
Rolling behaviour of sows in relation to piglet crushing on sloped versus level floor pens 总被引:1,自引:0,他引:1
Lone Danholt Vivi Aarestrup Moustsen Mai Britt Friis Nielsen Anders Ringgaard Kristensen 《Livestock Science》2011,141(1):59-68
The study focused on the rolling behaviour of sows and the crushing of piglets by sows' rolling behaviour. The experiment examined the influence of sloped floor in loose housed farrowing pens on the rolling behaviour of sows and crushing of piglets. The experimental unit was made up of 24 pens. There were two experimental pen designs with piglet creep in the corner of the pen and piglet creep across the end of the pen, respectively. Both of the experimental pen designs had a 10% sloped floor in the sow's resting area. The two control pen designs were identical to the experimental pen designs, but with a level floor. The behaviour of 85 sows and their litters was continuously video recorded. Behavioural observations were made from birth of the first piglet and until 3 days after birth of the first piglet. Rolling behaviour of sows caused significantly more trapped piglets under the sow than lying down from standing (P = 0.04). Rolling behaviour caused 64% of the trapped piglets and lying down from standing caused 36% of the trapped piglets. Rolling from udder to side without protection trapped significantly more piglets than rolling from udder to side near slanted wall or piglet protection rails and rolling from side to udder (P < 0.001). With a certain pen design sloped floor reduced rolling from udder to side without protection (P = 0.007) and reduced the number of trapped piglets (P = 0.01), but results concerning lying behaviour showed that sloped floor pushed sows to rest on the level part of the floor. The results indicate that rolling behaviour that crushes piglets can be reduced, and sows prefer to lie on a level floor. 相似文献
74.
Sara Hareardóttir Marina Pan?i? Anna Tammilehto Bernd Krock Eva Friis M?ller Torkel Gissel Nielsen Nina Lundholm 《Marine drugs》2015,13(6):3809-3835
Diatoms of the genus Pseudo-nitzschia produce domoic acid (DA), a toxin that is vectored in the marine food web, thus causing serious problems for marine organisms and humans. In spite of this, knowledge of interactions between grazing zooplankton and diatoms is restricted. In this study, we examined the interactions between Calanus copepodites and toxin producing Pseudo-nitzschia. The copepodites were fed with different concentrations of toxic P. seriata and a strain of P. obtusa that previously was tested to be non-toxic. The ingestion rates did not differ among the diets (P. seriata, P. obtusa, a mixture of both species), and they accumulated 6%–16% of ingested DA (up to 420 µg per dry weight copepodite). When P. seriata was exposed to the copepodites, either through physical contact with the grazers or separated by a membrane, the toxicity of P. seriata increased (up to 3300%) suggesting the response to be chemically mediated. The induced response was also triggered when copepodites grazed on another diatom, supporting the hypothesis that the cues originate from the copepodite. Neither pH nor nutrient concentrations explained the induced DA production. Unexpectedly, P. obtusa also produced DA when exposed to grazing copepodites, thus representing the second reported toxic polar diatom. 相似文献
75.
Narong TIPTANAVATTANA Araya RADTANAKATIKANON Poul HYTTEL Hanne HOLM Supranee BURANAPRADITKUN Piyathip SETTHAWONG Mongkol TECHAKUMPHU Theerawat THARASANIT 《The Journal of reproduction and development》2015,61(6):581-588
The development of germ cells has not been entirely documented in the cat especially the transition phase of
the gonocyte to the spermatogonial stem cell (G/SSC). The aims of study were to examine testicular development
and to identify the G/SSC transition in order to isolate and culture SSCs in vitro. Testes
were divided into 3 groups according to donor age (I, < 4 months; II, 4–6 months; and III, > 6 months).
In Exp. 1, we studied testicular development by histology, transmission electron microscopy and
immunohistochemistry. In Exp. 2, we determined the expression of GFRα-1, DDX-4 and c-kit and performed flow
cytometry. The SSCs isolated from groups II and III were characterized by RT-PCR and TEM (Exp. 3).
Chronological changes in the G/SSC transition were demonstrated. The size, morphology and ultrastructure of
SSCs were distinguishable from those of gonocytes. The results demonstrated that group II contained the
highest numbers of SSCs per seminiferous cord/tubule (17.66 ± 2.20%) and GFRα-1+ cells (14.89 ±
5.66%) compared with the other groups. The findings coincided with an increased efficiency of SSC derivation
in group II compared with group III (74.33 ± 2.64% vs. 23.33 ± 2.23%). The colonies expressed
mRNA for GFRA1, ZBTB16, RET and POU5F1.
Our study found that the G/SSC transition occurs at 4–6 months of age. This period is useful for isolation and
improves the establishment efficiency of cat SSCs in vitro. 相似文献
76.
Cells of Mycoplasma flocculare were found to vary in size and shape, especially in the later phases of growth, whereas those of Mycoplasma hyopneumoniae were fairly uniform irrespective of growth phases. Filamentous cells were present in cultures of M flocculare in the stationary and declining phases, but were never found in cultures of M hyopneumoniae. The filamentous and bizarre forms observed when mycoplasmas were suspended in phosphotungstic acid probably result from the action of the hypotonic solution. The surface of all cells was covered by a fuzzy coat consisting of fine hairs or bristles. An electron-lucent region was usually seen in cells negatively stained after centrifugation, but was only occasionally seen in cells negatively stained directly from the medium. Intracytoplasmic membranes were present in sectioned cells. No attachment organelle was found in cells of either species. 相似文献
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