The impacts of season and livestock management strategy on the quality of diets selected by goats and sheep in the semi-arid rangelands of Namaqualand,South Africa     

Francuois L Müller  Clement F Cupido  Melvin BV Swarts  Nefza M Amary  Dawood Hattas 《African Journal of Range and Forage Science》2019,36(2):105-114

Access to good-quality forages is one of the major limitations to livestock production in semi-arid pastoral systems. This study aimed to determine whether there are differences in the nutritional quality of diets selected by herded and free-ranging goat and sheep flocks utilising Namaqualand Granite Renosterveld vegetation during the wet and dry seasons. Plant samples collected along the grazing routes of livestock were dried and analysed for their fibre, condensed tannin, total phenolic and mineral nutrient contents. The study showed that a large variety of forages were on offer and livestock groups selected different diets of which some were different to the total diet on offer. In general, significant deficiencies in phosphate, protein and energy in the diets selected by herded and free-ranging goats and sheep were observed in both wet and dry season. The quality of the diets selected by herded and free-ranging livestock was also found to be different from each other, with herded livestock generally selecting more nutrient-dense diets. Herding, therefore, allows livestock to access better-quality forage in the Namaqualand Granite Renosterveld rangeland, where it is generally poor.  相似文献   

Time-patterns of antibiotic exposure in poultry production--a Markov chains exploratory study of nature and consequences     

Chauvin C  Clement C  Bruneau M  Pommeret D 《Preventive veterinary medicine》2007,80(2-3):230-240

This article describes the use of Markov chains to explore the time-patterns of antimicrobial exposure in broiler poultry. The transition in antimicrobial exposure status (exposed/not exposed to an antimicrobial, with a distinction between exposures to the different antimicrobial classes) in extensive data collected in broiler chicken flocks from November 2003 onwards, was investigated. All Markov chains were first-order chains. Mortality rate, geographical location and slaughter semester were sources of heterogeneity between transition matrices. Transitions towards a 'no antimicrobial' exposure state were highly predominant, whatever the initial state. From a 'no antimicrobial' exposure state, the transition to beta-lactams was predominant among transitions to an antimicrobial exposure state. Transitions between antimicrobial classes were rare and variable. Switches between antimicrobial classes and repeats of a particular class were both observed. Application of Markov chains analysis to the database of the nation-wide antimicrobial resistance monitoring programme pointed out that transition probabilities between antimicrobial exposure states increased with the number of resistances in Escherichia coli strains.  相似文献   

Cytotoxicity on human cancer cells of ophidiacerebrosides isolated from the African starfish Narcissia canariensis     

Farokhi F  Wielgosz-Collin G  Clement M  Kornprobst JM  Barnathan G 《Marine drugs》2010,8(12):2988-2998

The starfish Narcissia canariensis harvested from the coasts off Dakar, Senegal, was investigated for glycolipids (GL). This report deals with the isolation, characterization and biological activity of a fraction F13-3 separated from the GL mixture and selected according to its ability to inhibit KB cell proliferation after 72 hours of treatment. Firstly, a GL mixture F13 was obtained that accounted for 1.36% of starfish biomass (dry weight) and 0.36% of total lipids. The fraction F13-3 obtained from F13 contained three homologous GL identified as peracetylated derivatives on the basis of chemical and spectroscopic evidence. These contained a β-glucopyranoside as sugar head, a 9-methyl-branched 4,8,10-triunsaturated long-chain aminoalcohol as sphingoid base and amide-linked 2-hydroxy fatty acid chains. The majority (63%) had an amide-linked 2-hydroxydocosanoic acid chain and was identified as the ophidiacerebroside-C, firstly isolated from the starfish Ophidiaster ophidiamus. The minor components of F13-3 differed by one more or one less methylene group, and corresponded to ophidiacerebroside-B and -D. We found that F13-3 displayed an interesting cytotoxic activity over 24 hours on various adherent human cancerous cell lines (multiple myeloma, colorectal adenocarcinoma and glioblastoma multiforme) with an IC(50) of around 20 μM.  相似文献   

Pea weevil, Bruchus pisorum L. (Coleoptera: Bruchidae), resistance in Pisum sativum×Pisum fulvum interspecific crosses     

S. L. Clement    K. E. McPhee  L. R. Elberson    M. A. Evans 《Plant Breeding》2009,128(5):478-485

The pea weevil, Bruchus pisorum (L.), is one of the most intractable pest problems of cultivated pea, Pisum sativum L., in the world. This study investigated the transfer of pea weevil resistance from two accessions (PI 595946, PI 343955) of wild pea, Pisum fulvum Sibth. & Sm., to interspecific populations derived from crossing these accessions with a weevil-susceptible pea cultivar ('Alaska 81'). Partial life tables characterized weevil stage-specific mortality and survivorship on parents and interspecific progeny in two glasshouse trials. Larval mortality rates on pods (F₃ plants) of several F_2:3 families were between 36.0% and 52.9%. These means were statistically similar to mean mortality rates on pods of resistant parents (45.4% and 46.2%), but significantly greater than mean rates on the susceptible parent (1.2% and 10.6%). Pod surface characteristics contributed to high neonate larval mortality on pods of resistant parents and interspecific progeny. Seed resistance was not broadly transferred to interspecific progeny [revealed by high weevil survivorship in seeds (means mostly >80%) and high seed damage ratings of 3–5 where ratings of 1–2 denote resistance (production of resistant seed averaged 4.2% to 22.8%)]. Estimates of total weevil mortality on pods and seeds of eight F_2:3 families were 50–70%. Thus, weevil resistance in the Pisum secondary gene pool can be transferred to interspecific progeny, thereby providing a potential avenue to develop weevil-resistant pea cultivars.  相似文献   

国内外36个苜蓿品种的发芽特性综合评价     

马婷燕  罗飞  Clement Nzabanita  李彦忠 《种子》2019,(1):44-53

苜蓿品种的优劣影响苜蓿草地建植与生产性能,其中发芽特性是首要指标。为筛选出优良的品种用于试验研究和生产,收集了我国育成苜蓿品种14个和国外22个品种的种子(其中包衣种子8个),测定了发芽率、硬实率、苗长等12个指标,采用隶属函数平均值法综合评价了品种优劣。结果表明,供试品种的千粒重为1.56～4.87g,发芽势为49.33%～97.33%(平均为83.52%),发芽率为49.33%～97.33%(平均为86.85%),发芽指数为5.83～17.04(平均为10.90),活力指数为0.18～0.60(平均为0.390),25个品种有硬实种子,其中,新疆大叶硬实率为49.33%显著高于其他品种,将硬实种子划破种皮继续培养,发芽率均有提升。综合指标评价最高的5个品种为甘农6号、中苜3号、甘农9号、耐盐之星、前景,综合指标评价最低的5个品种为公农5号、WL 168HQ、WL 354HQ、太阳神、新疆大叶。我国品种综合指标较高,平均为0.51,国外品种平均为0.44,国内品种表现优于国外品种。  相似文献   

Response of a gorgonian (Paramuricea clavata) population to mortality events: recovery or loss?     

R. Cupido  S. Cocito  S. Sgorbini  A. Bordone  G. Santangelo 《水产资源保护:海洋与淡水生态系统》2008,18(6):984-992

• 1. During late summer 1999 and 2003 two mass mortality events affected the population of the slow growing, long‐lived Mediterranean gorgonian Paramuricea clavata living in the Gulf of La Spezia (Italy).
• 2. The population was monitored for three years after the mortality events. Availability of pre‐event data (1998) allowed comparison of population density and population size structure of the healthy population with those recorded in the three years following the mortality events.
• 3. In 1998, before the two mass mortality events, mean colony density was 33.3 ± 3.7 colonies m^?2 and had fallen to 6.7 ± 1.9 colonies m^?2 in 2004.
• 4. In the post‐event period the population size structure changed and the modal class of colonies shifted from 16–21 cm to 6–15 cm height.
• 5. In 2004 mortality affected 75 ± 6.4% of colonies. A significant, positive correlation between the extent of damage and colony size was found throughout the monitoring period.
• 6. In the three years following the two mortality events, a small increase in density of recruits and of older undamaged colonies was recorded suggesting that the population was slowly recovering.
• 7. The bathymetric distribution of P. clavata straddles the summer thermocline making this population particularly sensitive to temperature increases. The lack of deeper colonies (less exposed to warming) and the geographical isolation of this population is likely to prevent any substantial external larval supply.
• 8. An increased frequency of mass mortality events associated with ever increasingly high temperature events represent a considerable threat to the persistence of a P. clavata population in the Gulf of La Spezia.

Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Nutritional value of dry‐extruded blends of seafood processing waste and plant‐protein feedstuffs in diets for juvenile red drum (Sciaenops ocellatus,L.)     

Fernando Yugo Yamamoto  Clement R. de Cruz  Waldemar Rossi  Delbert M. Gatlin 《Aquaculture Nutrition》2020,26(1):88-97

Six thermally processed blends were manufactured by dry‐extruding mixtures of seafood processing waste with either soybean meal (SBM) or distiller's dried grains with solubles (DDGS) at three different ratios (50:50, 60:40 and 70:30; wet basis). To assess the energy and nutrient digestibility of each blend, a digestibility trial was conducted using advanced red drum juveniles (~70 g). After computing the apparent digestibility coefficients for the mixtures, a comparative feeding trial evaluated replacement of menhaden fishmeal (FM) on digestible protein (DP) and digestible energy (DE) bases with the manufactured blends. A diet formulated to derive 70% of DP from FM and 30% from SBM served as a Control. Groups of 14 fish were stocked in 21, 110‐L aquaria operating as a recirculating aquaculture system, and treatments were randomly distributed in triplicate. Weight gain and feed efficiency of fish fed SBM 50:50, DDGS 50:50 and DDGS 60:40 were significantly lower compared to that of fish fed the Control diet. However, the inclusion of SBM 60:40, SBM 70:30 and DDGS 70:30 blends succeeded in partially replacing FM and reducing fish oil inclusion in the diet of red drum without compromising production performance.  相似文献   

Induction of systemic resistance to Agrobacterium tumefaciens by endophytic bacteria in grapevine     

Susan Asghari  Behrouz Harighi  Morahem Ashengroph  Christophe Clement  Aziz Aziz  Qassim Esmaeel  Essaid Ait Barka 《Plant pathology》2020,69(5):827-837

Crown gall disease of grapevine, caused by Agrobacterium tumefaciens, often results in severe economic loss to grape production worldwide. This study demonstrated the ability of the endophytic bacteria Pseudomonas sp. Sn48 and Pantoea sp. Sa14 isolated from domesticated and wild grapevines to induce resistance in both above- and belowground tissues of grapevines infected with A. tumefaciens. Our results provide evidence that both strains can colonize roots and/or shoots. We showed that the strains Pseudomonas sp. Sn48 and Pantoea sp. Sa14 are capable of inducing stilbenic phytoalexin production in grapevine tissues and to further prime plantlets for enhanced phytoalexin production after A. tumefaciens inoculation. We also showed that in the majority of treatments, polyamine accumulation remained unchanged or slightly increased in plantlets treated with Pseudomonas sp. Sn48 and Pantoea sp. Sa14 compared with the control. Our findings indicated that the levels of polyamines remain unchanged or significantly decrease in plantlets treated with endophytic bacteria after A. tumefaciens challenge compared to the control and plantlets treated with individual endophytic bacterial strains. PR1, PR2, and PR4 gene expression levels of plantlets treated with Pseudomonas sp. Sn48 and Pantoea sp. Sa14 significantly increased after A. tumefaciens inoculation. The findings revealed the efficacy of the selected endophytic bacteria in triggering grapevine resistance against A. tumefaciens and the possible use of these strains as an alternative to chemical control methods in grapevine crown gall disease management.  相似文献   

The impact of prolonged hyperinsulinaemia on glucose transport in equine skeletal muscle and digital lamellae          下载免费PDF全文

M. A. de Laat  C. K. Clement  M. N. Sillence  C. M. McGowan  C. C. Pollitt  V. A. Lacombe 《Equine veterinary journal》2015,47(4):494-501

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A wood densitometer using direct scanning with X-rays     

D. J. Cown  B. C. Clement 《Wood Science and Technology》1983,17(2):91-99

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