Assessing the relationship between the rumen microbiota and feed efficiency in Nellore steers

Background:Ruminants rely upon a complex community of microbes in their rumen to convert host-indigestible feed into nutrients.However,little is known about the association between the rumen microbiota and feed efficiency traits in Nellore(Bos indicus)cattle,a breed of major economic importance to the global beef market.Here,we compare the composition of the bacterial,archaeal and fungal communities in the rumen of Nellore steers with high and low feed efficiency(FE)phenotypes,as measured by residual feed intake(RFI).Results:The Firmicutes to Bacteroidetes ratio was significantly higher(P<0.05)in positive-RFI steers(p-RFI,low feed efficiency)than in negative-RFI(n-RFI,high feed efficiency)steers.The differences in bacterial composition from steers with high and low FE were mainly associated with members of the families Lachnospiraceae,Ruminococcaceae and Christensenellaceae,as well as the genus Prevotella.Archaeal community richness was lower(P<0.05)in p-RFI than in n-RFI steers and the genus Methanobrevibacter was either increased or exclusive of p-RFI steers.The fungal genus Buwchfawromyces was more abundant in the rumen solid fraction of n-RFI steers(P<0.05)and a highly abundant OTU belonging to the genus Piromyces was also increased in the rumen microbiota of highefficiency steers.However,analysis of rumen fermentation variables and functional predictions indicated similar metabolic outputs for the microbiota of distinct FE groups.Conclusions:Our results demonstrate that differences in the ruminal microbiota of high and low FE Nellore steers comprise specific taxa from the bacterial,archaeal and fungal communities.Biomarker OTUs belonging to the genus Piromyces were identified in animals showing high feed efficiency,whereas among archaea,Methanobrevibacter was associated with steers classified as p-RFI.The identification of specific RFI-associated microorganisms in Nellore steers could guide further studies targeting the isolation and functional characterization of rumen microbes potentially important for the energy-harvesting efficiency of ruminants.

Evaluation of Four Methods for Restoring a Degraded Swamp Forest

Swamp Forests occur in permanently wet soils, with specific ecosystem which contributes to the conservation of biodiversity and water resources. However, there are many gaps in knowledge about the restoration of these forests. The present study was conducted in a degraded wetland in the town of Mineiros do Tietê, located in the state of S?o Paulo, Brazil, in order to test the efficiency of four methods for restoring a Swamp Forest (small mound, acclimated seedling, dry season and conventional tillage), using six forest tree species typical of this type of forest: Calophyllum brasiliense Cambess., Citharexylon myrianthum Cham., Cedrela odorata L., Tapirira guianensis Aubl., Ficus insipida Willd. and Croton urucurana Baill. The least favorable methods for all plant species were: conventional and soil pit tillageindry seasons. Analyzing the plant species individually, the best results in descending order were: Croton urucurana Baill. (acclimated seedling tillage in dry season), followed by Calophyllum brasiliense Cambess. (insmall mounds), Citharexylon mirianthum Cham. (with acclimated seedlings), Ficus insipida Willd. and Tapirira guianensis Aubl. (insmall mounds). Cedrela odorata L. presented low performance in all conditions, probably because it suffered the Hypsipyla grandella Zeller. The results have been successful for the establishment of Swamp Forest restoration strategies.

The role of green manure nitrogen use by corn and sugarcane crops in Brazil

Three assays were developed from April 3, 1995 to October 10, 2005. The work with corn was conducted in a greenhouse, using velvet bean (Mucuna aterrima) and sunn hemp (Crotalaria juncea) as green manure with 15N labeling of either shoots or roots, in two soils with contrasting textural classes. The mineralization of N from legume plants incorporated into the two soils was investigated too. This work included two green manures: velvet bean and sunn hemp, and the common bean (Phaseolus vulgaris) residues. Nitrogen from the velvet bean accounted for a greater proportion of the soil inorganic N;shoots were responsible for most of N accumulated. Common bean residues caused immobilization of inorganic N. The leguminous species added were intensively and promptly mineralized, preserving the soil native nitrogen. One hundred days after emergence of the corn, velvet bean provided higher accumulation of nitrogen in the soil, higher absorption by corn plants and accumulation in the aerial part. The green manure decomposition was more intense in the medium textured soil. In this soil, highest nitrogen losses were also observed. The sugarcane (Saccharum spp.) was cultivated for five years in the field and was harvested three times;15N recovery was evaluated in the first two harvests. The combination of inorganic fertilizer and green manure resulted in higher sugarcane yields than either N source applied separately;however, in the second cutting the yields were higher where sunn hemp was used than in plots with ammonium sulfate. The recovery of N by the first two consecutive harvests accounted for 19% to 21% of the N applied as sunn hemp and 46% to 49% of the N applied as ammonium sulfate. Very little inorganic N was present in the 0-40 cm soil layer with both N sources.

The Role of Nitrogen Fertilizers in Sugarcane Root Biomass under Field Conditions

Sugarcane is used worldwide for sugar, ethanol and energy production. In Brazil, the shift from burned to unburned harvest systems resulted in increases in nitrogen fertilization rates, which can impact root architecture and biomass. The expectation is also an increase in sugarcane biomass. The study hypothesized that high N rates applied to sugarcane fields increases root growth and N stored in roots, promoting higher biomass and N accumulated in shoots. Two experiments were set up in Southeastern Brazil, on a Typic Kandiudox (TK) and Rhodic Eutrudox (RE). Four treatments were studied 1) N application in the plant-cane (0 and 120 kg·ha-1 N) and 2) N application in the ratoon (0 and 150 kg·ha-1 N). The shoot biomass and the root density (by the core method up to 0.6 m) were evaluated over the first ratoon crop cycle, and the N content in those compartments was also examined. There was no carry over effect on N applied at planting in root and shoot biomass in the ratoon crop cycle. At the RE site, the ratoon N fertilization increased root density in the superficial soil layer (0 - 0.2 m) and close to the plants (<0.3 m). The effect of N addition on root biomass, and biomass and N accumulated in shoot was limited in both sites. Increasing N rates in unburned sugarcane fields do not consistently increases root and shoot biomass under Brazilian field conditions.

Effect of Infestation of <i>Alabama argillacea</i>(Lepidoptera: Noctuidae) at Different Ages of Cotton Plants in Yield

The cotton leafworm is an important defoliating pest of cotton in Brazil, and occurs in all regions where the crop is cultivated. The purpose of this study was to evaluate the effect of larval densities of A. argillacea after different infestation periods on the yield components of four cotton cultivars. The experiment was carried out in Pindorama, SP, Brazil, in the 2008/2009 growing season. The cultivars IAC-25, DeltaOPAL, Fibermax 966 and Fibermax 993 were artificially infested with A. argillacea larvae at three times (30, 60 and 90 DAE) and four densities (0, 2, 4, and 6 larvae per plant). The average boll weight (g), fiber percentage (%), 100-seed weight (g) and yield (kg·ha-1) were evaluated. With increasing infestation density of A. argillacea, the cotton yield of the cultivars decreased. The presence of larvae significantly reduced the weight of 100 seeds of cultivar Fibermax 966. Initial infestations reduced the boll weight of IAC-25 and DeltaOPAL, while cultivars Fibermax 966 and Fibermax 993 were most affected by late infestations. Early infestation compromised fiber percentage of cultivar DeltaOPAL and late infestations were most harmful to cultivar Fibermax 966. Early A. argillacea infestation reduced the yield of DeltaOPAL, while infestations 60 DAE caused the most damage to IAC-25, and the other cultivars were not affected by the moment of infestation.

Damage Caused by Psyllids and Influence of Climatic Factors in Brazilian Accesses of Guava Trees Cultivated in Organic System

The psyllid (Triozoida sp.) is the primary pest of guava tree in the Central Northern region of S?o Paulo State, Brazil. The variation of climatic factors may influence directly or indirectly the behavior of agricultural pests. The present work had objectives to evaluate the damages caused by psyllid in accesses of guava trees in order to identify materials with potential resistance to pest and the possible correlations of the damage with the meteorological factors, in an orchard of guava conducted in an organic system. Eighty-five guava accesses were evaluated. Each one was analyzed at random 10 leaves containing the symptom of the psyllid attack, through visual range of notes. The averages of the notes were compared by Scott-Knott test at 5% probability. The 25 accesses with the highest average damage of psyllid had the data submitted to correlation (Pearson), with the minimum and maximum temperature (°C), precipitation (mm) and relative humidity (%). Guava accesses used commercially were the most susceptible to the attack of psyllid, compared to the selections, with an emphasis to access “L4P14”, “L7P28” and “L8P32B”, which were the least attacked. The study of correlation between psyllid damages and meteorological factors, must be used the medium temperature, relative humidity and rainfall accumulated in the period of 14 days before the evaluations. There is a positive correlation between minimum temperasture, precipitation and relative humidity with the damage of psyllids in leaves of guava.

可持续的不锈钢交通运输建筑设计

引人注目且具可持续性的交通运输建筑设施是当代讲求效率的基础设施建筑中的重要组成部分。除拥有夺目的外观外,经正确选择的不锈钢具有更佳的耐久性,维护要求最少,可长期安全使用并保持安防和交通控制的功能。不锈钢这些特性及其内在的可持续性,使其成为世界范围内新建交通设施的重要设计材料。因此,重新审视不锈钢的应用、优点及规格将给设计者以信心,在那些设计使用寿命50年以上的作品中选用不锈钢材料进行设计。

Infestation of Diatraea saccharalis(Fabr.)during Five Consecutive Cycles of Sugarcane Crop Succeeding Leguminous Crops

The area cultivated with sugarcane in Brazil is expanding, and increasingly using legumes cover crop in new deployed areas and in those which were reformed. Long-term trials were carried out in Piracicaba, Sao Paulo, Brazil, to evaluate the effect of leguminous green manure on the natural infestation of Diatraea saccharalis (Fabr.) during five cropping cycles of sugarcane “IAC 87-3396”. This study was carried out from October 1999 to October 2005 in Piracicaba, Sao Paulo, Brazil, at coordinates 22°42''S and 47°38''W, 560 m above sea level, in soil classified as Typic Paleudult. Green manure crops were assigned to five treatments: peanuts (Arachis hypogaea L.) (cultivar “IAC-Tatu” and “IAC-Caiapó”), sunn hemp (Crotalaria juncea L.) (cultivar “IAC 1”) and velvet-bean [Mucuna aterrima (Piper & Tracy) Holland] (cultivar “common”). A treatment without any green manure or weed was used as the control. The previous sugarcane crop was destroyed and the soil was prepared in a conventional way (using plow and harrow) before the leguminous crops were sowed. Thirty days after the sowing, weeds were removed and, 120 days later, the crops were cut and its biomass was deposited on the soil surface without incorporation. Experimental plots comprised five rows of sugarcane, each one measuring 10 m long and spaced 1.40 m apart. The sugarcane was harvested 18 months after biomass deposit, on October 25th, 2001 and its stalks were collected at intervals of approximately 12 months in: 07/09/2002, 08/01/2003, 11/07/2004 and 10/06/2005. At harvest, the masses were determined from a sample of sugarcane, cut from three rows (2 m long) in the center of the plot. The losses caused by the sugarcane borer were estimated by the intensity of the infestation by randomly observing and collecting sugarcane stems from each plot. A great reduction in the number of stalks and in the yield was noted proportionally to the intensity of the infestation of the borer in the sugarcane crop grown after the velvet-bean. The sugarcane-velvet-bean rotation should be regarded considering the intensity of sugarcane borer infestation. No influence of the other green manure crops was observed on the intensity of the infestations. However, the harvest seasons of the sugarcane seemed to influence the borer infestation.

Response of Moderate Pest Resistant and Susceptible Cultivar of Sugarcane to Silicon Application

In this study, the effects of a silicon (Si) application on the biomass, chlorophyll level and silicon level of sugarcane moderate pest resistance (RB72454) and susceptible (SP801842) cultivars were tested. Investigations were also carried out to assess the effect of silicon on Diatraea saccharalis infestation. The experiments were conducted in a greenhouse using the treatments consisting moderate pest resistant and susceptible culivar, with or without silicon application. The silicon was applied to the soil around the plants. The experiment was laid in complete randomized design with 4 treatments and 10 replicates. The data were subjected to an analysis of variance, and the averages were compared using the Tukey test (p ≤ 0.05). Significant changes were observed in the fresh and dry masses of the aerial portions and the root system, as well as in the plant chlorophyll and silicon levels. The silicon content increased in the susceptible variety which was significantly equal for moderate resistance variety. Chlorophyll content increased in silicon treated cultivars. Sixty days after the last application, 10 adult D. saccharalis moths were released onto each pot. However, due to the low infestation, the effects of silicon on the insect incidence could not be determined. One can conclude that silicon is beneficial for the growth of the aerial portions of sugarcane and causes a significant increase in chlorophyll levels.

Weed Control Strips Influences on the Rubber Tree Growth

Hevea brasiliensis (rubber tree) is the most widely cultivated tree species for producing natural rubber latex whose productivity can be reduced by weeds. Field experiment was carried out during two years to evaluate the growth of rubber tree plants submitted to different weed control strips (0-weed-free, 50, 100, 150, 200, 250, 300, 350, and 400-(weedy cm) and to determine the critical width of weed control strip during the establishment of rubber tree plantation. Weed community was composed mainly by Urochloa decumbens (90%). The width of the weed control strip influenced on the initial plant growth of rubber trees, reducing the plant height, stem diameter, leaf area, and aboveground dry mass accumulation. In consequence, crop plantation was affected by the width of weed control. The critical width of the weed control strip for establishment of a rubber tree plantation was within 100 cm.

Harmonia axyridis Pallas(Coleoptera:Coccinellidae):Biological aspects and thermal requirements

The aim of this study was to determine the biological aspects and thermal requirements of Harmonia axyridis Pallas (Coleoptera: Coccinellidae) fed daily with Anagasta kuehniella (Zeller) (Lep-idoptera: Pyralidae) eggs. Under laboratory conditions, the experiment was carried out in acclimatized chambers set to 18°C, 21°C, 24°C, 27°C, and 30°C. Larvae of H. axyridis were separated, kept in a glass tube, and fed with A. kuehniella eggs. The Asiatic lady beetle adults were separated into 20 couples and kept in plastic cups receiving the same food as the larvae. The length of the larval, pupal, and total biological cycle (from egg to adult) stages declined significantly from 18°C to 27°C, but was stable between 27°C and 30°C. Survival was similar for larvae from the first to the fourth stadium when kept at 18°C, 21°C, and 24°C with a higher total biological cycle survival at 27°C. H. axyridis males presented higher longevity at 18°C and 21°C in comparison to females that had a longer life and a higher fecundity at 24°C and 27°C, respectively. The lower thermal limit for biological cycle development was 12.4°C, and the thermal constant was 243.9 degree-days.