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951.
Ahmed S. A. Abbas Eman El-Wazzan Amal R. Khafage Abdel-Fattah M. El-Sayed Fatma A. Abdel Razek 《Aquaculture International》2018,26(5):1297-1309
Studies considering broodstock conditioning of Ruditapes decussatus mostly used flagellates and diatoms for feeding, mainly Isochrysis galbana and Chaetoceros calcitrans, respectively. The present study evaluated the effect of different microalgal diets on gonadic maturation of R. decussatus including three microalgae species (C. calcitrans, Tetraselmis suecica, and Nannochloropsis oculata) which were used to prepare six diets: three monospecific and three bispecific mixed diets at a proportion of 1:1. Clams were daily fed at a ratio of 1% dry weight of algae/live weight of clam and unfed treatment was used as control. Results showed that clams fed C. calcitrans alone or mixed with T. suecica attained earlier full maturity with the highest response to spawning induction (after 34 conditioning days) and largest proportion in the partial spawning phase for both, followed by T. suecica alone after 48 days. In contrast, N. oculata alone or mixed diets demonstrated poor performance for gonadal maturation. Unfed treatment did not show any sign of maturation. The results indicated that T. suecica has high conditioning potential like C. calcitrans and their mixture gave the highest benefit. Therefore, T. suecica can be recommended for R. decussatus broodstock conditioning. 相似文献
952.
Solomon Benor Frank R. Blattner Sebsebe Demissew Karl Hammer 《Genetic Resources and Crop Evolution》2010,57(2):293-306
Little information is available regarding the biodiversity and potential use of jute (Corchorus species) in Ethiopian agriculture. The present study summarizes species’ occurrence, use, geographical distribution, ecology,
and ethnobotany of Corchorus species in Ethiopia. An ecogeographical study, conducted in the Amhara, Oromia and Gambella Regional States in 2005 and 2008
resulted in the collection of seven different species with more than 100 accessions. The study revealed low similarity in
species composition between the Regional States, indicating that each region has its own unique set of species. Species numbers
are higher in the north-eastern and south-western than the central part of the country. C. aestuans L. and C. tridens L. are restricted to humid lowlands of south-western part of Ethiopia, growing at elevations up to 490 m, whereas, C. urticifolius Wight et Arn., C. trilocularis L. and C. schimperi Cufod. were collected only in the north-eastern part of the country with elevation ranges of 1,380–2,130 m. The only species
collected at a higher elevation (>2,100 m) was C. schimperi Cufod. Farmers’ perception, indigenous knowledge and folk taxonomy of jute species are better in Gambella than the other
studied regions. Although several Corchorus species are reported from Ethiopia, these species are neither cultivated nor popularly used as leafy vegetables. This is
mainly due to lack of awareness or knowledge about the species use, and abundant distribution of the species that allows gathering
of edible leaves with little expenditure of time, labour and other resources. Our results revealed that some species are threatened,
which necessitates highest priority for jute germplasm conservation in the country. In addition, creating public awareness
about the use of jute species as a cheap source of leafy vegetable will play an important role to diversify food sources,
reduce malnutrition, and contribute to household income generation of the farming community. 相似文献
953.
Martin G. Maquivar Carlos S. Galina Jaime R. Galindo Sandra Estrada Rafael Molina German David Mendoza 《Tropical animal health and production》2010,42(4):555-560
In order to evaluate the effect of protein supplementation on the productive and reproductive performance of heifers, 45 Bos indicus × Bos taurus heifers, 673 ± 146 days of age and weighing about 340 kg, were divided into two groups. The control group (n = 23) continued without supplementation, but the supplemented group (SG; n = 22) received concentrate at a rate of 1% BW kg per day. Animals were adapted to the concentrate over a 15-day period and
then supplemented for 30 days, after which estrus was synchronized using a progesterone implant. Back fat thickness (BFT)
was assessed by ultrasound. The SG had better average daily weight gain than the nonsupplemented group (0.63 ± 0.16 vs. 0.51 ± 0.13 kg/day,
P < 0.05) and tended to show a better percentage ovulation (P < 0.10, 77% vs. 57%, respectively). However, this tendency was not reflected in the final pregnancy rates. No differences
were observed between groups in dry matter intake and body condition scores. SG with a high BFT (>0.70 cm) showed a better
ovulation percentage than those with low BFT (<0.69 cm; P < 0.01). Additionally, the pregnancy rate of supplemented heifers with high BFT tended to be better than heifers with low
BFT in this same group (67% vs. 30%, respectively, P < 0.10). It is concluded that protein supplementation improved reproductive performance and that ultrasonography to measure
BFT may be used to estimate reproductive performance. 相似文献
954.
K Ashley S Wilson JR Young HP Chan S Vitou S Suon PA Windsor RD Bush 《Tropical animal health and production》2018,50(1):63-73
Forage technology has been successfully introduced into smallholder cattle systems in Cambodia as an alternative feed source to the traditional rice straw and native pastures, improving animal nutrition and reducing labour requirements of feeding cattle. Previous research has highlighted the positive impacts of forage technology including improved growth rates of cattle and household time savings. However, further research is required to understand the drivers, challenges and opportunities of forage technology for smallholder cattle households in Cambodia to facilitate widespread adoption and identify areas for further improvement. A survey of forage-growing households (n = 40) in July–September 2016 examined forage technology adoption experiences, including reasons for forage establishment, use of inputs and labour requirements of forage plot maintenance and use of forages (feeding, fattening, sale of grass or seedlings and silage). Time savings was reported as the main driver of forage adoption with household members spending approximately 1 h per day maintaining forages and feeding it to cattle. Water availability was reported as the main challenge to this activity. A small number of households also reported lack of labour, lack of fencing, competition from natural grasses, cost of irrigation and lack of experience as challenges to forage growing. Cattle fattening and sale of cut forage grass and seedlings was not found to be a widespread activity by interviewed households, with 25 and 10% of households reporting use of forages for these activities, respectively. Currently, opportunities exist for these households to better utilise forages through expansion of forage plots and cattle activities, although assistance is required to support these households in addressing current constraints, particularly availability of water, if the sustainability of this feed technology for smallholder cattle household is to be established in Cambodia. 相似文献
955.
Junzeng Xu Yuping Lv Likun Ai Shihong Yang Yupu He Twecan Dalson 《Paddy and Water Environment》2017,15(2):381-393
Based on data collected from rice fields under drying–wetting cycle condition, the procedure of dual-crop coefficient (K cd) approaches was calibrated and validated to reveal its feasibility and improve its performance in rice evapotranspiration (ET c) estimation. It was found that K cd based on FAO-recommended basal crop coefficients (K cb) underestimated dual-crop coefficients in monsoon climate region in East China. The recommended coefficient (K cp) value of 1.2 was not high enough to reflect the pulse increase of rice ET c after soil wetting. The K cb values were calibrated as 1.52 and 0.63 in midseason and late season, and the K cp value was adjusted as 1.29 after soil wetting in rice field under drying–wetting cycle condition. The dual-crop coefficient curves based on locally calibrated K cbCal and K cpCor matched well with the measured crop coefficients and performed well in calculating rice evapotranspiration from paddy fields under drying–wetting cycle condition. So it can be concluded that the procedure of dual-crop coefficient method is feasible in rice ET c estimation, and locally calibrated K cb and K cp can improve its performance remarkably. 相似文献
956.
Rosmawati Effendi Abustam Abu Bakar Tawali Muhammad Irfan Said Dwi Kesuma Sari 《Fisheries Science》2018,84(6):1081-1089
Snakehead fish (Channa striata) skin is a fishery by-product that has the potential for further processing because it contains a high amount of organic matter. This study investigates the effect of body weight on the chemical composition and collagen content of snakehead fish skin. This study used fresh snakehead fish of either gender. Their body weights were divided into three groups: small, medium, and large size. The characteristics of snakehead fish skin included proximate composition, amino acid content, collagen content, microstructure, and minerals. Snakehead fish skin from fish of different body weights indicated that the moisture content and ash tended to decrease, the protein content was relatively stable, and the lipid content tended to increase with increasing body weight. Glycine and proline comprised the highest percentages of amino acids at all levels of body weight, and the presence of hydroxyproline showed that snakehead fish skin was the source of collagen. There was no significant difference in body weight observed on collagen protein content of the skin. This study on the microstructure and mineral content of snakehead fish skin can be used as supporting information to promote the potential utility and economic value of the skin. 相似文献
957.
Maintaining connectivity among local populations in a fragmented landscape is crucial for the survival of many species. For
isolated habitat patches, stochastic fluctuations and reduced gene flow can lead to high risk of extinction. The connectivity
of the landscape is especially crucial for the carabid species living in the fragmented forests of the Bereg plain (NE Hungary
and W Ukraine) because a highway will be constructed through the plain. Our purpose is to (1) evaluate the impacts of three
possible highway tracks, (2) suggest a solution that is realistic with less impact on connectivity than other plans and (3)
discuss how to decrease the disadvantageous effects of each track. Our results, based on a network analysis of landscape graph
of patches and ecological corridors, indicate that the intended highway could have deleterious consequences on forest-living
carabids. Relatively simple actions, like the establishment of stepping stones, could compensate for the loss of habitat connectivity
and promote the survival of carabids, or minor modifications in one possible track could diminish its adverse effects. While
many other studies would be needed for a comprehensive assessment of the biotic impact of the highway, we provide an example
on the usefulness of network analysis for land use management.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
958.
A mixture neural methodology for computing rice consumptive water requirements in Fada N’Gourma Region, Eastern Burkina Faso 总被引:1,自引:1,他引:1
Seydou Traore Yu-Min Wang Chun-E. Kan Tienfuan Kerh Jan Mou Leu 《Paddy and Water Environment》2010,8(2):165-173
Crop consumptive water requirement (Crop-ET) is a key variable for developing management plans to optimize the efficiency
of water use for crop production particularly in semiarid zone. In Burkina Faso, the unfavorable climatic conditions characterized
by the low and unevenly distribution of rainfall have pushed water resources management to the forefront of the crop production
issue. Crop-ET is extremely required in rainwater effective management for mitigating the impact of water deficit on the crops.
Basically, Crop-ET determination involves reference evapotranspiration (ETo) and crop coefficient (Kc) which required complete
climatic data and specific site crop information, respectively. ETo estimation with the recommended FAO56 Penman–Monteith
(PM) equation is limited in Burkina Faso due to the numerous meteorological data required which are not always available in
many production sites. In such circumstances, research to compute directly Crop-ET as an alternative to the two-step approach
of calculating ETo and determining site specific Kc, seems desirable. Therefore, this study aims to evaluate the performance
of a mixture principal component analysis neural network (PCANN) model for computing rice Crop-ET directly from temperatures
data in Fada N’Gourma region located in Eastern Burkina Faso, Africa. From the statistical results, rice Crop-ET can be successfully
computed by using PCANN methodology, when only temperatures data are available in this African semiarid environment. Thus,
in poor data situation, Crop-ET direct computation can be rapidly addressed through PCANN model for agricultural water management
in African semiarid regions. 相似文献
959.
Maria Teresa Melillo Paola Leonetti Antonella Leone Pasqua Veronico Teresa Bleve-Zacheo 《European journal of plant pathology / European Foundation for Plant Pathology》2011,130(4):489-502
Nitric oxide (NO) has been shown to be an essential regulatory molecule in plant response to pathogen infection in synergy
with reactive oxygen species (ROS). At the present, nothing is known about the role of NO in disease resistance to nematode
infection. We used a resistant tomato cultivar with different sensitivity to avirulent and virulent populations of the root-knot
nematode Meloidogyne incognita to investigate the key components involved in oxidative and nitrosative metabolism. We analyzed the superoxide radical production,
hydrogen peroxide content, and nitric oxide synthase (NOS)-like and nitrate reductase activities, as potential sources of
NO. A rapid NO accumulation and ROS production were found at 12 h after infection in compatible and incompatible tomato-nematode
interactions, whereas the amount of NO and ROS gave different results 24 and 48 h after infection amongst compatible and incompatible
interactions. NOS-like arginine-dependent enzyme rather than nitrate reductase was the main source of NO production, and NOS-like
activity increased substantially in the incompatible interaction. We can envisage a functional overlap of both NO and ROS
in tomato defence response to nematode invasion, NO and H2O2 cooperating in triggering hypersensitive cell death. Therefore, NO and ROS are key molecules which may help to orchestrate
events following nematode challenge, and which may influence the host cellular metabolism. 相似文献
960.
Maria Pukalchik Maria Panova Mikhail Karpukhin Olga Yakimenko Kamila Kydralieva Vera Terekhova 《Journal of Soils and Sediments》2018,18(3):750-761