Effect of trehalose supplementation in milk replacer on the incidence of diarrhea and fecal microbiota in preweaned calves

Trehalose, a nonreducing disaccharide consisting of d-glucose with α,α-1,1 linkage, was evaluated as a functional material to improve the gut environment in preweaned calves. In experiment 1, 173 calves were divided into two groups; the trehalose group was fed trehalose at 30 g/animal/d with milk replacer during the suckling period, and the control group was fed nonsupplemented milk replacer. Medication frequency was lower in the trehalose group (P < 0.05). In experiment 2, calves (n = 20) were divided into two groups (control group [n = 10] and trehalose group [n = 10]) based on their body weight and reared under the same feeding regimens as in experiment 1. Fresh feces were collected from individual animals at the beginning of the trial (average age 11 d), 3 wk after trehalose feeding (experimental day 22), and 1 d before weaning, and the fecal score was recorded daily. Fecal samples were analyzed for fermentation parameters and microbiota. The fecal score was significantly lower in the trehalose group than in the control group in the early stage (at an age of 14 to 18 d; P < 0.05) of the suckling period. Calves fed trehalose tended to have a higher proportion of fecal butyrate on day 22 than calves in the control group (P = 0.08). Population sizes of Clostridium spp. were significantly lower (P = 0.036), whereas those of Dialister spp. and Eubacterium spp. tended to be higher in the feces of calves in the trehalose group on day 22 (P = 0.060 and P = 0.083). These observations indicate that trehalose feeding modulated the gut environment and partially contributed to the reduction in medication frequency observed in experiment 1.     

Identification of novel juvenile-hormone signaling activators via high-throughput screening with a chemical library

Juvenile hormone (JH) is an insect-specific hormone that regulates molting and metamorphosis. Hence, JH signaling inhibitors (JHSIs) and activators (JHSAs) can be used as effective insect growth regulators (IGRs) for pest management. In our previous study, we established a high-throughput screening (HTS) system for exploration of novel JHSIs and JHSAs using a Bombyx mori cell line (BmN_JF&AR cells) and succeeded in identifying novel JHSIs from a chemical library. Here, we searched for novel JHSAs using this system. The four-step HTS yielded 10 compounds as candidate JHSAs; some of these compounds showed novel basic structures, whereas the others were composed of a 4-phenoxyphenoxymethyl skeleton, the basic structure of several existing JH analogs (pyriproxyfen and fenoxycarb). Topical application of seven compounds to B. mori larvae significantly prolonged the larval period, suggesting that the identified JHSAs may be promising IGRs targeting the JH signaling pathway.     

Genetic mapping of AFLP markers in Japanese bunching onion (<Emphasis Type="Italic">Allium fistulosum</Emphasis>)

Summary The first genetic linkage map of Japanese bunching onion (Allium fistulosum) based primarily on AFLP markers was constructed using reciprocally backcrossed progenies. They were 120 plants each of (P₁)BC₁ and (P₂)BC₁ populations derived from a cross between single plants of two inbred lines: D1s-15s-22 (P₁) and J1s-14s-20 (P₂). Based on the (P₂)BC₁ population, a linkage map of P₁ was constructed. It comprises 164 markers – 149 amplified fragment length polymorphisms (AFLPs), 2 cleaved amplified polymorphic sequences (CAPSs), and 12 simple sequence repeats (SSRs) from Japanese bunching onion, and 1 SSR from bulb onion (A. cepa) – on 15 linkage groups covering 947 centiMorgans (cM). The linkage map of P₂ was constructed with the (P₁)BC₁ population and composed of 120 loci – 105 AFLPs, 1 CAPS, and 13 SSRs developed from Japanese bunching onion and 1 SSR from bulb onion – on 14 linkage groups covering 775 cM. Both maps were not saturated but were considered to cover the majority of the genome. Nine linkage groups in P₂ map were connected with their counterparts in P₁ map using co-dominant anchor markers, 13 SSRs and 1 CAPS.     

Interactive effects of leaf age and self-shading on leaf structure,photosynthetic capacity and chlorophyll fluorescence in the rain forest tree,Dryobalanops aromatica

In the tropical canopy tree, Dryobalanops aromatica Gaertn. f., upper-canopy leaves (UL) develop under sunlit conditions but are subjected to self-shading within the crown as they age. In contrast, lower-canopy leaves (LL) are exposed to uniform dim light conditions throughout their life span. By comparing leaf morphology and physiology of UL and LL, variations in leaf characteristics were related to leaf age and self-shading. Mass-based chlorophyll (chl) concentration and the chlorophyll/nitrogen (chl/N) ratio were lower and the chl a/b ratio was higher in UL than in LL. In UL, the chl/N ratio gradually increased and the chl a/b ratio gradually decreased with leaf aging, whereas these ratios remained unchanged with leaf age in LL. The effective quantum yield of photosystem II (PSII) (DeltaF/F(m)') at a given irradiance remained unchanged with leaf age in LL, whereas DeltaF/F(m)' changed with leaf age in UL. These data indicate N reallocation within the leaves from carbon fixation components to light harvesting components and a dynamic regulation of photochemical processes of PSII in response to increased self-shading of UL. Despite the difference in light environment with leaf age between UL and LL, maximum photosynthetic rates and nitrogen-use efficiency decreased with leaf aging in both UL and LL. Constancy in the chl/N ratio with leaf age in LL indicated that the decrease in photosynthetic capacity was caused by effects other than shading, such as leaf aging. We conclude that N reallocation and acclimation of PSII to self-shading occurred even in mature leaves, whereas the change in photosynthetic capacity with leaf age was more conservative.     

Needle longevity, photosynthetic rate and nitrogen concentration of eight spruce taxa planted in northern Japan

Growth characteristics of Picea glehnii Masters, P. jezoensis (Sieb. et Zucc) Carr., P. jezoensis var. hondoensis (Mayr) Rehder and P. shirasawae Hayashi from Japan, P. abies (L.) Karst. from Europe and P. glauca Voss, P. mariana Britt., Sterns and Pogg. and P. rubens Sarg. from North America were compared. The trees were grown in similar conditions at the Tomakomai Experimental Forest of Hokkaido University in northern Japan. Tree growth, needle biomass, longevity, photosynthetic rate, nitrogen concentration and specific leaf area (SLA) were measured, and photosynthetic nitrogen-use efficiency was calculated. Picea jezoensis, P. jezoensis var. hondoensis, P. abies and P. glauca had high growth rates, high photosynthetic rates in young needles, high needle nitrogen concentrations and short needle life spans. In contrast, P. glehnii, P. shirasawae, P. mariana and P. rubens had low growth and photosynthetic rates, low needle nitrogen concentrations, long needle life spans and maintained a high photosynthetic nitrogen-use efficiency in older needles. Examination of relationships between several growth parameters of the eight taxa revealed positive correlations between SLA and mass-based photosynthetic rate and between SLA and mass-based nitrogen concentration, whereas mass-based photosynthetic rate and mass-based nitrogen concentration were negatively correlated with needle longevity. The species differed greatly in growth characteristics despite being grown in similar conditions.     

Reckoning social forestry in Bangladesh: policy and plan versus implementation

The history of scientific forest management in Bangladesh datesback to the nineteenth century with defined forest policiesand laws. Due to various socio-economic and socio-politicalfactors, forest cover of the country reduced drastically andall such policy initiatives proved ineffective. Although traditionalforest management objectives covered a wide range from economicbenefit to ecological stability, these have never been attainedfully. Huge population and limited land area compelled policymakers to think about alternatives to traditional forest management.One alternative, social forestry, was introduced in Bangladeshin early 1980s and has proved to be extremely successful. Whiletraditional forest management resulted in a net loss of forestresource cover, social forestry on the other hand, is playinga vital role in the expansion of forest cover (40 387 ha ofnew forest cover and 48 420 km new strip plantation since themid-1980s) benefiting thousands of poor people. Results showthat during the last four years (2000–2003) more than23 000 individuals benefited from the final felling of differentsocial forestry plantations (woodlot, agroforestry and stripplantation). This generated a total income of US$ 5.6 millionfor the government and US$ 5.3 million for participants plusUS$ 1.2 million for the Tree Farming Fund – a 10 per centdepository reserve to sustain the practice in the long run.Although average individual final returns (US$ 223 person^–1)are not so attractive, some people got about US$ 5000 to US$8500 from final felling, sufficient to improve their standardof living and social position. Despite the success so far achieved,social forestry in Bangladesh still suffers from various institutionaldeficiencies like organization, skilled manpower, legitimateusufruct rights, peoples' participation from policy to implementationand clear budgetary arrangements. Besides, until now the roleof relevant actors is not well defined in all the steps of socialforestry practice in Bangladesh. Unless the participants aregiven clear legitimate usufruct rights, they will remain scepticaltowards this programme. They should have good and meaningfulaccess from planning to implementation. In the context of institutionaldevelopment, there are governmental policy guidelines and a20-year Master Plan for Bangladesh. Although some steps havebeen partially completed, there is still much to do to complywith forest policy guidelines and the Master Plan. It is shownthat in the last seven years (1995/96–2001/2002) onlyUS$ 15.41 million a^–1 has actually been spent againstan allocated sum of US$ 68.37 million a^–1. Therefore,if the intention is to institutionalize social forestry in Bangladesh,government and policy makers should actively come forward. Otherwisethe full potential of social forestry in Bangladesh will notbecome a reality.     

使用Li-6400测定森林土壤呼吸应注意的几个问题

正确使用Li-6400进行森林土壤呼吸测定是保证测定精度的前提.本文以落叶松林为例,对Li-6400使用过程应该注意的问题进行了研究.结果表明:塑料圈至少应该测定前12小时进行设置,以减少土壤CO2涌出效应对呼吸的影响,而且塑料圈插入深度对测定结果影响很大:当塑料圈插入过浅时横向气体扩散及塑料圈不稳定而造成测定时CO2的再涌出效应使土壤呼吸测定值偏高;而当插入深度过深时,切断根系导致根系呼吸下降,最活跃的土壤表层呼吸受塑料圈阻隔导致的土壤微生物呼吸测定值下降,这些现象共同造成显著低估土壤呼吸测定值.此外,在晴天白天大部分时间内目标[CO2]值设定为外界相应时段的[CO2]平均值,可以保证测定误差小于5%,而在清晨和傍晚进行测定时,则应该及时调整目标值为外界[CO2]保证测量准确性.这一测定原则在实际测定中具有较高的实用性.     

Seasonal and yearly variations in light use and nitrogen use by seedlings of four deciduous broad-leaved tree species invading larch plantations

Several deciduous broad-leaved tree species, differing in leaf phenology, invade larch (Larix kaempferii (Lamb.) Carrière) plantations in Japan. The understory light environment of larch forests changes drastically between the leafy and leafless periods. To determine how the invading seedlings exploit the changing light environment, and if phenological differences reflect the light- and nitrogen-use traits of the seedlings, we measured leaf phenology, seasonal changes in light-saturated photosynthetic rate (P(sat)), leaf nitrogen (N) content (N(area)), chlorophyll/nitrogen ratio (Chl/N), specific leaf area (SLA) and N remobilization rate (NRMR) over 3 years. The mid-successional or gap-phase species, Magnolia hypoleuca Siebold & Zucc., had a short leafy period and high P(sat) and NRMR. In contrast, two late-successional tree species, Prunus ssiori Friedr. Schmidt, which undergoes leaf flush before larch, and Carpinus cordata Blume, which maintains green leaves until frost, both had low P(sat) and NRMR but exploited the opportunity for growth during the period when the larch canopy trees were leafless. Quercus mongolica Fisch. ex Ledeb. var. crispula (Blume) Ohashi, a mid-late-successional species that underwent leaf flush at the same time as the overstory larch, had values of photosynthetic parameters between those of the gap-phase and late-successional species. Among species, M. hypoleuca and Q. mongolica had higher photosynthetic rates and photosynthetic N-use efficiencies. In all species, the relationship between N(area) and P(sat) showed species-specific yearly fluctuations; however, there was no yearly fluctuation in the relationship between N(area) and P(sat) at CO2 saturation. Yearly fluctuations in the N(area)-P(sat) relationship appeared to be induced by changes in SLA and N-use characteristics, which in turn are affected by climatic variations.     

Growth, Net Photosynthetic Rate, Nutrient Status and Secondary Xylem Anatomical Characteristics of Fagus Crenata Seedlings Grown in Brown Forest Soil Acidified with H2SO4 Solution

Dry matter production, net photosynthetic rate, leaf nutrient status and trunk anatomical characteristics of Fagus crenata seedlings grown in brown forest soil acidified by adding H₂SO₄ solution were investigated. The soil acidification leaded to decreased (Ca+Mg+K)/Al molar ratio in the soil solution. Dry mass per plant of the seedlings grown in the soil treated with H⁺ at 120 mg·L^?1 was significantly reduced compared with the control value at 0 mg·L^?1. When net photosynthetic rate was reduced in the seedlings grown in the soil treated with H⁺ at 120 mg·L^?1, the carboxylation efficiency and maximum net photosynthetic rate at saturated CO₂-concentration were lower than the control values. The addition of H⁺ to the soil at 120 mg·L^?1iinduced a reduction in the concentration of Ca in the leaf. By contrast, the concentration of Al in the leaf was increased with increasing the amount of H⁺ added to the soil. The annual ring formed in the seedlings grown in the soil treated with H⁺ at 120 mg·L^?1 was significantly narrower than that at 0 (control), 10, 30, 60 or 90 mg·L^?1. Based on the results obtained in the present study, we conclude that Fagus crenata is relatively sensitive to a reduction in the (Ca+Mg+K)/Al molar ratio of soil solution compared with Picea abies.     

Improvement of functional properties of egg white protein through phosphorylation by dry-heating in the presence of pyrophosphate

Egg white protein (EWP) was phosphorylated by dry-heating in the presence of pyrophosphate at pH 3.0-7.0 and 85 degrees C for 1 and 5 days, and the functional properties of the phosphorylated EWP (PP-EWP) were investigated. The phosphorylation was accelerated with a decrease of pH from 7.0 to 3.0 and for heating times from 1 to 5 days. The phosphorus content of EWP increased approximately 1.05% by dry-heating at pH 4.0 and 85 degrees C for 5 days in the presence of pyrophosphate, which was higher than that of casein. The electrophoretic mobility of EWP increased with an increase in the phosphorylation level. The surface hydrophobicity of EWP increased by phosphorylation. The heat stability, emulsifying properties, and digestibility of EWP were improved by phosphorylation. The calcium phosphate-solubilizing ability of EWP was enhanced by phosphorylation. A firmer and transparent heat-induced gel of PP-EWP was obtained, and the water-holding capacity of heat-induced PP-EWP gel was higher that that of the control. These results suggest that phosphorylation by dry-heating in the presence of pyrophosphate is a useful method for improving the functional properties of EWP.