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41.
对16～46周龄的蛋鸡生产性能的研究表明,交替饲喂或喂混合饲料的效果是不同的。一种方法是利用同等比例的整粒小麦或营养均衡的含蛋白质及矿物质浓缩的饲料交替饲喂ISA布朗母鸡,另一种方法是饲喂混合饲料。对照组喂传统的饲料。每组16笼,每笼中5只鸡。每天光照时间16h。控制饲料的饲喂量,121g·只-·1d-1,每天饲喂2次,分别为开灯后4h和11h。在交替饲喂时,仅第1次喂食小麦,第2次喂食营养的均衡饲料。喂混合饲料时,两种定量配给的饲料混合喂2次。在下一次喂食前拿走剩余的饲料。与喂混合饲料和对照组相比,交替饲喂减少总采食量,小麦减少9g·只-·1d-1,但喂均衡饲料增多1.7g·只-·1d·-1。在3种方式中,鸡蛋的生产,蛋的大小,蛋的重量均相似。交替饲喂与喂混合饲料相比,饲料利用率的提高分别为10%和5%。与喂混合饲料和对照组相比,交替饲喂ME低,CP摄取量减少。交替饲喂时蛋鸡体重轻,其肌胃、胰腺和肝脏较重,肝脏脂质类似。喂混合饲料肝糖最高。试验结论为,交替饲喂整粒小麦和营养均衡的饲料或喂混合饲料对蛋鸡生产无负面影响。因此,两种饲喂方法是可以替代传统的喂养方式。与喂混合饲料相比,交替饲喂饲料的利用效率高,因而是可行的。 相似文献
42.
Jaya Das Samira H. Daroub Jehangir H. Bhadha Timothy A. Lang Orlando Diaz Willie Harris 《Journal of Soils and Sediments》2012,12(6):952-965
Purpose
Excess nutrients such as phosphorus (P) transported from the Everglades Agricultural Area (EAA) in South Florida, USA, to downstream water bodies have been identified as contributing to trophic imbalances within the Florida Everglades. Decades of farming drainage from the EAA has led to accumulation of sediments in regional canals which may be transported to downstream ecosystems and act as potential internal source of P.Materials and methods
Intact sediment cores were collected from three main conveyance and three farm canals within the EAA. Physicochemical assessment, mineralogy, P speciation, and storage were determined for surface and subsurface layers.Results and discussion
The main conveyance canal sediments had higher total P (TP) concentrations (1,280?±?360?mg?kg-1) than the farm canals (960?±?540?mg?kg-1), while farm canal sediments showed higher organic matter content (28?C53?%) compared to the main canal (24?C27?%) sediments. The minerals found in main conveyance canal sediments were similar to those found in Lake Okeechobee. The labile KCl?CP fraction comprised <2?% of TP from all canal sediments, while NaOH?CPi (i?=?inorganic) fraction consisted of 1?C14?% of TP. The majority of P in the canal sediments was contained in the HCl?CP fraction (Ca?CP and Mg?CP), comprising >50?% of TP in the main and farm canal sediments. An estimated 73 metric tons (mt) of P was stored in the 0?C10-cm layer of the three main conveyance canals within the EAA boundary of which 57-mt P is reactive and potentially available for release at different time scales.Conclusions
The EAA canal sediments are highly organic with low bulk density and susceptible of being transported to downstream ecosystems. Many factors can impact the potential release of the reactive stored P, including redox potential of sediments as well as the overlying water column P concentration. Further investigation of potential P release from these sediments is warranted. 相似文献43.
Genetic and immunobiological diversities of porcine reproductive and respiratory syndrome genotype I strains 总被引：1，自引：0，他引：1
Darwich L Gimeno M Sibila M Diaz I de la Torre E Dotti S Kuzemtseva L Martin M Pujols J Mateu E 《Veterinary microbiology》2011,150(1-2):49-62
Genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) has been based on ORF5/GP5 and ORF7/N protein variations. Complete viral genome studies are limited and focused on a single or a few set of strains. Moreover, there is a general tendency to extrapolate results obtained from a single isolate to the overall PRRSV population. In the present study, six genotype-I isolates of PRRSV were sequenced from ORF1a to ORF7. Phylogenetic comparisons and the variability degree of known linear B-epitopes were done considering other available full-length genotype-I sequences. Cytokine induction of all strains was also evaluated in different cellular systems. Non structural protein 2 (nsp2) was the most variable part of the virus with 2 out of 6 strains harboring a 74 aa deletion. Deletions were also found in ORF3 and ORF4. Phylogenetic analyses showed that isolates could be grouped differently depending on the ORF examined and the highest similarity with the full genome cluster was found for the nsp9. Interestingly, most of predicted linear B-epitopes in the literature, particularly in nsp2 and GP4 regions, were found deleted or varied in some of our isolates. Moreover, 4 strains, those with deletions in nsp2, induced TNF-α and 3 induced IL-10. These results underline the high genetic diversity of PRRSV mainly in nsp1, nsp2 and ORFs 3 and 4. This variability also affects most of the known linear B-epitopes of the virus. Accordingly, different PRRSV strains might have substantially different immunobiological properties. These data can contribute to the understanding of PRRSV complexity. 相似文献
44.
Carlos Henry Loáisiga Agnese Kolodinska Brantestam Oscar Diaz Björn Salomon Arnulf Merker 《Genetic Resources and Crop Evolution》2011,58(7):1021-1028
Teosintes are the closest relatives to modern maize, Zea mays L. ssp. mays. They are wild grasses with a native distribution area from Mexico to Nicaragua and represent an important genetic resource.
However, the genetic diversity of Nicaraguan teosinte (Zea nicaraguensis Iltis et Benz) has not yet been determined. This teosinte species has decreased in the last 25 years and now must be regarded
as an endangered species. An analysis of the genetic diversity of Zea nicaraguensis was carried out in a total of 240 individuals from seven populations. Eleven Simple Sequences Repeat (SSR) primer pairs were
used. A total of 42 alleles were found, the range of alleles per locus was 2–5 (mean 3.8) and the numbers of genotypes varied
between primers. The primer Bnlg 1538 showed the highest value, with 45 genotypes through all populations. The genetic diversity observed (Ho) between all
populations varied from 0.51 to 0.63, with an average of 0.563. One of the populations had as many as 40 alleles. Analysis
of molecular variance (AMOVA) revealed that most of the variation was within population, at a significantly high level (P < 0.001). Rare alleles were detected in all populations, but unique alleles were only found in four populations. These results
are highly relevant when developing conservation strategies and show that preserving populations in their natural habits is
highly important. 相似文献
45.
46.
Iara Del Pilar Solar Diaz Gregório Miguel Ferreira de Camargo Valdecy Aparecida Rocha da Cruz Isis da Costa Hermisdorff Caio Victor Damasceno Carvalho Lucia Galvão de Albuquerque Raphael Bermal Costa 《Reproduction in domestic animals》2020,55(11):1650-1654
Although the second largest chromosome of the genome, the X chromosome is usually excluded from genome-wide association studies (GWAS). Considering the presence and importance of genes on this chromosome that are involved in reproduction, the aim of this study was to evaluate the effect of its inclusion in GWAS on reproductive traits (scrotal circumference [SC], early pregnancy [P16] and age at first calving [AFC]) in a Nelore herd. Genotype data from 3,263 animals with the above-mentioned phenotypes were used. The results showed an increase in the variances explained by the autosomal markers for all traits when the X chromosome was not included. For SC, there was an increase of more than 10% for the windows on chromosomes 2 and 6. For P16, the effect was increased by almost 20% for windows on chromosome 5. The same pattern was found for AFC, with an increase of more than 10% for the most important windows. The results indicate that the noninclusion of the X chromosome can overestimate the effects of autosomes on SC, P16 and AFC not only because of the additive effect of the X chromosome itself but also because of its epistatic effect on autosomal genes. 相似文献
47.
Objective
To elucidate the structure of terminal inverted duplications and to investigate potential mechanisms of formation in two cases where there was mosaicism with cells of apparently normal karyotype.Results
A karyotype [46,XY,inv dup(4)(p16.3p15.1)/46,XY] performed on blood lymphocytes from a patient referred for developmental delay (case 1) demonstrated a normal karyotype in 60% of cells with a terminal inverted duplication 4p in the remainder. In case 2, referred for multiple fetal anomalies on an ultrasound scan, 33% of amniocyte colonies were karyotypically normal, with a terminal inv dup 10p in the remainder [46,XX,inv dup(10)(p15.3p11)/46,XX]. Duplicated FISH signals for GATA3 and NEBL loci (in case 2), and for the Wolf-Hirschhorn locus (case 1) confirmed the inverted structure of both duplications. In the GTL banded normal cells from both cases, there was a cryptic deletion detected by FISH of one copy of the subtelomere 4p (case 1, probe GS-36P21), and subtelomere 10p (case 2, probe GS-306F7). At pter on both inv dup chromosomes there was no FISH signal present for the specific subtelomere probe. However, a positive pantelomeric probe signal was detected at 4 pter and 10 pter in both the cryptically-deleted chromosomes and the inv dup chromosomes in the respective cell lines of both cases.Conclusion
An inv dup structure was evident for both cases on GTL bands, and confirmed by the various FISH studies. The presence of telomere (TTAGGG repeat) sequences at pter on the inv dup chromosomes (where more proximal chromosome specific subtelomeric probes were negative) was indicated by the pantelomeric probe signals in both cases. We conclude the most likely mechanism of origin in both cases was by sub-telomeric breakage in the zygote at pter, and delayed repair/rearrangement until after one or more subsequent mitotic divisions. In these divisions, at least one breakage-fusion-bridge cycle occurred, to produce inverted duplications. It is proposed then that two differently "repaired" daughter cells proliferated in parallel. In one daughter cell line (with an overtly normal karyotype) there was deletion of the subtelomere and presumed repair through capping by a neo-telomere (i.e. "healing", as initially proposed by McClintock). This occurred in both cases presented. In the other daughter cell of each case, it is proposed that chromosome stabilization was achieved (after replication) by sister chromatid reunion to form a dicentric, which broke at a subsequent anaphase, to form an inverted duplication (with loss of the reciprocal product, and the other daughter cell line). One inv dup was repaired without an interstitial specific subtelomere (case 1) and one was repaired with a duplicated specific interstitial subtelomere (case 2). After repair TTAGGG repeats were detected by FISH at each respective new pter.48.
Pablo M. Vergara Luis O. Meneses Audrey A. Grez Madelaine S. Quiroz Gerardo E. Soto Christian G. Pérez-Hernández Paola A. Diaz Ingo J. Hahn Andrés Fierro 《Landscape Ecology》2017,32(2):279-293
Context
Interactions between landscape-scale processes and fine-grained habitat heterogeneity are usually invoked to explain species occupancy in fragmented landscapes. In variegated landscapes, however, organisms face continuous variation in micro-habitat features, which makes necessary to consider ecologically meaningful estimates of habitat quality at different spatial scales.Objectives
We evaluated the spatial scales at which forest cover and tree quality make the greatest contribution to the occupancy of the long-horned beetle Microplophorus magellanicus (Coleoptera: Cerambycidae) in a variegated forest landscape.Methods
We used averaged data of tree quality (as derived from remote sensing estimates of the decay stage of single trees) and spatially independent pheromone-baited traps to model the occurrence probability as a function of multiple cross-scale combinations between forest cover and tree quality (with scales ranging between 50 and 400 m).Results
Model support and performance increased monotonically with the increasing scale at which tree quality was measured. Forest cover was not significant, and did not exhibit scale-specific effects on the occurrence probability of M. magellanicus. The interactive effect between tree quality and forest cover was stronger than the independent (additive) effects of tree quality and particularly forest cover. Significant interactions included tree quality measured at spatial scales ≥200 m, but cross-scale interactions occurred only in four of the seven best-supported models.Conclusions
M. magellanicus respond to the high-quality trees available in the landscape rather than to the amount of forest per se. Conservation of viable metapopulations of M. magellanicus should consider the quality of trees at spatial scales >200 m.49.
50.
The fungicides benomyl, captan, hymexazol, iprodione, propamocarb hydrochloride and thiram were applied in a combined schedule to Pinus halepensis seedlings grown under nursery conditions to study their effect on mycorrhiza formation and plant growth. The inoculated fungi Pisolithus tinctorius (strains 3SR and Mx) and Lactarius deliciosus formed mycorrhizas when fungicides were applied. However, fungicide application led to a significant decrease of mycorrhizal plants with Pisolithus tinctorius strain 3SR (from 62% without fungicides to 35% with fungicides). This effect could be attributed to a direct effect of fungicides on mycelial growth. The morphometric and nutritional parameters were very similar in plants treated with or without fungicides, and no differences on sanitary status of plants were noted. The use of preventive fungicide treatments in plant production, which may have a harmful effect on the environment, is therefore questioned. 相似文献