Effect of supplementation of multi-microbe probiotic product on growth performance, apparent digestibility, cecal microbiota and small intestinal morphology of broilers

The present study investigated the effect of inclusion of multi-microbe probiotic product on growth performance, apparent digestibility of nutrients, cecal microbiota and small intestinal morphology in broilers. Four hundred days-old Ross chicks were randomly allotted to five treatments on the basis of body weight (BW). Each treatment had four replicates of 20 chicks in each. Experimental diets were fed in two phases, starter (day 0-21) and finisher (day 22-35). Dietary treatments were; basal diet without any antimicrobial (NC), basal diet added with 20 mg Avilamycin/kg of diet (PC), 10(7) cfu multi-microbe probiotic/kg of diet (P1), 10(8) cfu multi-microbe probiotic/kg of diet (P2), and 10(9) cfu multi-microbe probiotic/kg of diet (P3). Overall BW gain and feed conversion ratio were better (p < 0.05) for treatments PC, P2 and P3 compared with NC and P1, with P1 being better (p < 0.05) than NC. Overall feed intake in treatments PC, P1, P2 and P3 were greater (p < 0.05) than NC. Apparent digestibility of dry matter and crude protein were greater (p < 0.05) in treatments PC, P2 and P3 compared with NC, with P1 being intermediate and not different form NC, PC, P2 and P3. At d 21 and 35, treatments PC, P1, P2 and P3 showed lower (p < 0.05) cecal Clostridium and Coliforms count in relation to NC. Moreover, cecal Clostridium (d 21) and Coliforms (d 21 and 35) count were lower (p < 0.05) in treatment PC in relation to P1; with P2 and P3 being intermediate and not different from PC. However, there was no effect of dietary treatments on cecal total anaerobic bacteria and Bifidobacterium spp. count. The villus height of duodenum in treatment PC was greater (p < 0.05) than NC, with P1, P2 and P3 being intermediate. Villus height of ileum in treatment PC was greater (p < 0.05) than in treatments P1 and NC, whereas it remained comparable among treatments PC, P2 and P3. Villus height to crypt depth ratio of ileum was greater (p < 0.05) for treatment PC, P2 and P3 compared with that in P1 and NC. It is concluded that multi-microbe probiotic inclusion at 10(8) and 10(9) cfu/kg diet had beneficial effects on broilers growth performance, apparent digestibility of nutrients and intestinal morphology and can be used as replacement to antibiotics growth promoter in broiler nutrition.     

玉米精播机漏播补偿系统设计

目前玉米免耕播种机的播种质量仍低于常规播种。本文讨论了微机控制的排种监测及漏播补偿装置，通过机电结合手段解决漏播问题。台架试验表明本装置能够准确发现漏播，并通过采取的措施实现及时补种，补种成功率可达90％以上。     

Herbicidal and biological characteristics of a new benzenesulfonylurea compound K-11451 under submerged paddy conditions

The new benzenesulfonylurea K-11451, an α-hydroxy-β-fluoropropyl- compound, applied at 3–9 g ha ⁻¹, controlled annual and perennial weeds grown in submerged paddy soil under greenhouse conditions. It effectively controlled barnyardgrass at growth stages varying from pre-emergence to the five-leaf stage. The compound inhibited acetolactate synthase, I₅₀ values for the enzyme isolated from barnyardgrass and rice being 56 and 67 nM , respectively. K-11451 inhibited the growth of rice when it was transplanted at a shallow depth (0–1 cm) and water leaching from the paddy soil was high (3–5 cm per day). With a water depth of 3 cm, the compound appeared to move readily down into the paddy soil and had the relatively short half-life of 15.2 days under submerged paddy conditions. A mixture of K-11451 + mefenecet + daimuron (9 + 250 + 250 g ha⁻¹) controlled almost all weeds in the paddy field without injury to rice, so that the combination could be used as a ‘one-shot’ herbicide in rice culture.     

Erwinia pyrifoliae, an Erwinia species different from Erwinia amylovora, causes a necrotic disease of Asian pear trees

Bacteria from necrotic branches of Asian pear trees ( Pyrus pyrifolia ) in Korea were consistently isolated as white colonies on nutrient agar and formed mucoid, slightly yellow colonies on a minimal medium with copper sulphate. Isolates with this colony morphology were studied in a series of microbiological, molecular and pathological tests. Most isolates allowed the verification of Koch's postulate on P. pyrifolia seedlings and on slices from immature pear ( Pyrus communis ) fruits and were also positive in hypersensitivity tests on tobacco leaves. They showed characteristics common to species in the genus Erwinia , but were different from Erwinia amylovora , the agent of fire blight. A relationship between the novel pathogen and E. amylovora was found in microbiological and serological tests. Both organisms had similar but not identical protein patterns in 2-D gel electrophoresis, and in growth morphology the new pathogen produced colonies on MM2 Cu medium that were mucoid and slightly yellow, compared with the clearly yellow colonies of E. amylovora . No similarity was found in the plasmid profiles, and consequently no PCR signal was obtained with primers from the E. amylovora plasmid pEA29. REP-PCR also produced bands differing for the two organisms.     

Dietary protein requirement for juvenile mandarin fish,Siniperca scherzeri

An 8‐week feeding trial was conducted to investigate the dietary protein requirement of juvenile mandarin fish, Siniperca scherzeri, a demersal freshwater piscivore with high commercial value in East Asia. Five isolipidic (100 g/kg) and isoenergetic (20 MJ/kg) practical diets were formulated to contain graded levels of 450, 500, 550, 600, and 650 g/kg crude protein, using mackerel fishmeal as the sole source of protein. Each of the five test diets was fed to visual satiety to triplicate groups of fish (initial mean body weight ± SE; 20.1 ± 0.2 g) reared in a recirculating freshwater system over the experimental period. Fish growth performance in terms of weight gain tended to improve with increasing dietary protein level, and the highest values were observed in those fish fed the 600–650 g/kg diets. Feed intake significantly declined as the protein content of the diet increased. Feed efficiency and protein retention tended to increase with increasing dietary protein levels, from 450 to 600 g/kg, and then declined when dietary protein content further increased to 650 g/kg. A similar trend was also found for the protein efficiency ratio, although the observed changes did not reach statistical significance. Whole‐body composition and plasma biochemical parameters were not significantly affected by the dietary protein content. Based on these findings and a broken‐line model of growth, 614.4 g/kg seems to be the proper amount of protein in a practical diet for >20 g mandarin fish.     

Getting cosy in freshwater: Assumed to be brackish pike are not so brackish after all

Pike (Esox lucius) occupy coastal streams and rivers of the Baltic Sea, where they attain large sizes (>5 kg). These large sizes are perhaps due to the fact that they can tolerate relatively high salinities and can thus forage in the nearby more productive brackish environments. In an attempt to quantify the extent to which pike utilise brackish environments, and to provide some insight into the underlying causes for brackish water migrations, we tagged 30 pike from a western Baltic river with acoustic transmitters and were able to track 21 individuals for 1 year. Based on experienced from local anglers, this population was assumed to be brackish in nature, where individuals underwent freshwater migrations to spawn. Our findings however suggest that the smallest and most active individuals make short exits into brackish waters and do so on rare occasions. Our results further indicate that neither sex nor size is related to activity level. We suggest that these patterns reflect two distinct behaviours—active and passive—and that large pike can be supported by the food availability in the river, without the need to venture into coastal zones, thus defying the conventional view that Baltic pike are all brackish in nature.     

Watermelon lycopene β-cyclase: promoter characterization leads to the development of a PCR marker for allelic selection

In the carotenoid biosynthetic pathway, lycopene β-cyclase (LCYB) catalyzes the cyclization that converts lycopene into β-carotene. Only a single copy of LCYB was identified and was suggested to encode a chromoplast-specific LCYB (CYCB type) in watermelon [Citrullus lanatus (Thunb.), Matsum & Nakai]. Splicing variants in the 5′-untranslated region were identified, but alternative splicing did not provide an explanation of the regulation of carotenoid accumulation in watermelon flesh. A quantitative assay using real time-PCR showed that differential expression was not detected between red- and canary yellow-fleshed watermelon cultivars. LCYB promoter regions were isolated and characterized, and a sequence difference was identified in the promoter region between red and canary yellow LCYB alleles. This polymorphism did not change the expression of LCYB, but does provide a reliable marker for discriminating LCYB alleles for red and canary yellow flesh. To develop a PCR-based marker to distinguish between the two LCYB alleles, we designed primers flanking the polymorphic region. The newly developed marker, designated Clcyb.600, co-segregated perfectly with flesh color phenotypes and single nucleotide polymorphism (SNP) markers developed in our previous study. Moreover, the Clcyb.600 marker offers easier discrimination of LCYB alleles than SNP or cleaved amplified polymorphic sequence markers, as it does not require restriction enzyme digestion for genotyping. Genotyping of LCYB promoter alleles in various commercial cultivars and plant introductions indicated that watermelon cultivars can be classified into two groups, those carrying a red LCYB allele or a canary yellow LCYB allele.     

A molecular technique for selection of self-compatible varieties of Japanese pear (Pyrus pyrifolia Nakai)

The pear cultivar ‘Osa-Nijisseiki’ (S₂S^sm ₄; sm = stylar-part mutant) has been used as a parent to breed self-compatible cultivars that produce excellent fruits. However, determination of the self-compatibility of ‘Osa-Nijisseiki’ offspring requires a lot of time, 6 years or more, by conventional cross breeding. We have designed a rapid reliable method for the identification of self-compatible varieties of ‘Osa-Nijisseiki’ offspring based on the polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) with S-allele specific restriction endonucleases. By using this method, 8 self-compatible varieties were selected among 16 selections resulting from a cross between the self-compatible cultivar ‘Osa-Nijisseiki’ (S₂S^sm ₄) and the self-incompatible cultivars ‘Niitaka’ (S₃S₉), ‘Whasan’ (S₃S₅), ‘Chuwhangbae’ (S₄S₆). The S-genotypes of 16 ‘Osa-Nijisseiki’ offsprings were also determined. This revised version was published online in August 2006 with corrections to the Cover Date.     

Functional genomics of microspore embryogenesis

Isolated plant microspores, when stressed and cultured in vitro, can be diverted from their normal gametophytic pathway towards sporophytic development, with the formation of haploid embryos and ultimately doubled-haploid plants. This process is called androgenesis or microspore embryogenesis, and is widely used in plant breeding programmes to generate homozygous lines for breeding purposes. Protocols for the induction of microspore embryogenesis and the subsequent regeneration of doubled haploid (DH) plants have been successfully developed for more than 200 species. These practical advances stand in stark contrast to our knowledge of the underlying molecular genetic mechanism controlling this process. The majority of information regarding the genetic and molecular control of the developmental switch from gametophytic to sporophytic development has been garnered from four intensely studied (crop) plants comprising two dicotyledonous species, rapeseed (Brassica napus) and tobacco (Nicotiana tabacum), and two monocotyledonous species, wheat (Triticum aestivum) and barley (Hordeum vulgare). In these species the efficiency of microspore embryogenesis is very high and reproducible, making them suitable models for molecular studies. In the past, molecular studies on microspore embryogenesis have focussed mainly on the identification of genes that are differentially expressed during this developmental transition and/or early in embryo development, and have identified a number of genes whose expression marks or predicts the developmental fate of stressed microspores. More recently, functional genomics approaches have been used to obtain a broad overview of the molecular processes that take place during the establishment of microspore embryogenesis. In this review we summarise accumulated molecular data obtained in rapeseed, tobacco, wheat and barley on embryogenic induction of microspores and define common aspects involved in the androgenic switch.     

Three AFLP markers tightly linked to the genic male sterility <Emphasis Type="Italic">ms</Emphasis><Subscript><Emphasis Type="Italic">3</Emphasis></Subscript> gene in chili pepper (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.) and conversion to a CAPS marker

Genic male sterility (GMS) has long been used as a tool for hybrid seed production in chili pepper (Capsicum annuum L.). We developed DNA markers linked to the GMS ms ₃ gene in a segregating population using bulked segregant analysis (BSA) and amplified fragment length polymorphism (AFLP) techniques. The segregating population was subjected to BSA-AFLP with 512 primer combinations. Three AFLP markers (Eagg/Mccc₂₇₆, Eagc/Mctt₁₇₈, and Ecag/Mtgc₂₀₄) were identified as tightly linked to the ms ₃ locus. Among them, we converted the AFLP marker Ecag/Mtgc₂₀₄ to the cleavage amplified polymorphic sequence (CAPS) marker, named GMS3-CAPS, based on sequencing analysis of internal and flanking regions for the markers between male-fertile and sterile plants. This marker will be useful for pepper breeding using the GMS system.