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Andrea Squartini - One of the best experts on this subject based on the ideXlab platform.

  • genome sequence of rhizobium sullae hcnt1 isolated from Hedysarum coronarium nodules and featuring peculiar denitrification phenotypes
    Genome Announcements, 2018
    Co-Authors: Sergio Casella, B De Diegodiaz, Laura Treu, Stefano Campanaro, V Da Silva Duarte, Marina Basaglia, Lorenzo Favaro, Andrea Squartini
    Abstract:

    ABSTRACT The genome sequence of Rhizobium sullae strain HCNT1, isolated from root nodules of the legume Hedysarum coronarium growing in wild stands in Tuscany, Italy, is described here. Unlike other R. sullae strains, this isolate features a truncated denitrification pathway lacking NO/N2O reductase activity and displaying high sensitivity to nitrite under anaerobic conditions.

  • Draft Genome Sequence of the Nitrogen-Fixing Rhizobium sullae Type Strain IS123T Focusing on the Key Genes for Symbiosis with its Host Hedysarum coronarium L.
    Frontiers in microbiology, 2017
    Co-Authors: Gaurav Sablok, Elisa Polone, Riccardo Rosselli, Torsten Seeman, Robin Van Velzen, Alessio Giacomini, Nicola La Porta, René Geurts, Rosella Muresu, Andrea Squartini
    Abstract:

    The prominent feature of rhizobia is their molecular dialogue with plant hosts. Such interaction is enabled by the presence of a series of symbiotic genes encoding for the synthesis and export of signals triggering organogenetic and physiological responses in the plant. The genome of the R.sullae type strain IS123T nodulating the legume Hedysarum coronarium, was sequenced and resulted in 317 scaffolds for a total assembled size of 7,889,576 bp. Its features were compared with those of genomes from rhizobia representing an increasing gradient of taxonomical distance, from a conspecific isolate (R.sullae WSM1592), to two congeneric cases (R.leguminosarum bv. viciae and R.etli,) and up to different genera within the legume-nodulating taxa. The host plant is of agricultural importance, but, unlike the majority of other domesticated plant species, it is able to survive quite well in the wild. Data showed that that the type strain of R.sullae, isolated from a wild host specimen, is endowed with a richer array of symbiotic genes in comparison to other strains, species or genera of rhizobia that were rescued from domesticated plant ecotypes. The analysis revealed that the bacterium by itself is incapable of surviving in the extreme conditions that its host plant can tolerate. When exposed to drought or alkaline condition, the bacteria depends on its host to survive. Data are consistent with the view of the plant phenotype as the primary factor enabling symbiotic nitrogen fixing bacteria to survive in otherwise limiting environments.

  • Shovel roots: a unique stress-avoiding developmental strategy of the legume plant Hedysarum coronarium L.
    Plant and Soil, 2009
    Co-Authors: Elisabetta Tola, Josè Liberato Henriquez-sabà, Elisa Polone, Frank B Dazzo, Giuseppe Concheri, Sergio Casella, Andrea Squartini
    Abstract:

    Hedysarum coronarium (sulla) is a legume native to the Mediterranean basin, known for its broad tolerance to various environmental stresses, and its ability to thrive without signs of chlorosis when growing in arid and alkaline soils up to pH 9.6. A unique but poorly known morphological feature of its root system is the production of "shovels", modified lateral roots that acquire a curved and flattened shape. A combined structural and functional analysis was undertaken to define the nature and role of the shovel roots using various microscopy techniques, histochemical stains, STEM - energy dispersive X-ray microanalysis, infrared spectroscopy, and plant cultivation in different conditions. We found that sulla displays remarkable unique rhizosphere-buffering properties at both ends of the pH scale, and that shovels act as efficient calcium-absorbing organs that accumulate this cation intracellularly as insoluble crystalline salts. Such bioaccumulation results in a localized depletion of CaCO(3) from the soil. As a consequence of this removal of the pivotal carbonate buffering system, the iron-solubilizing acidification activities of the roots can become effective. Further tests revealed that the factor triggering shovel development is exposure of roots to iron oxide. This signal, reporting at once both iron presence and alkalinity, assures the availability of iron nutrient reserves upon acidification of the local microenvironment surrounding the roots. These findings, besides casting light on a novel and unique botanical phenomenon, offer the potential to exploit sulla's model and genes for the improvement of other crops to sustain productivity in a scenario of climate warming and increasing desertification

  • rhizobium sullae sp nov formerly rhizobium hedysari the root nodule microsymbiont of Hedysarum coronarium l
    International Journal of Systematic and Evolutionary Microbiology, 2002
    Co-Authors: Andrea Squartini, Alessio Giacomini, Paolo Struffi, Heidi Doring, Sonja Selenskapobell, E Tola, Elena Vendramin, Encarna Velazquez, Pedro F Mateos, Eustoquio Martinezmolina
    Abstract:

    This work is the completion of a series of reports describing the nitrogen-fixing bacterial symbionts of sulla (Hedysarum coronarium L., Leguminosae) and providing the grounds for their proposal as a new taxon. The introduction summarizes a large amount of previous evidence gathered on the physiology, genetics and ecology of such organisms, which have in the past been referred to provisionally as 'Rhizobium hedysari'. Upon adding 16S RNA sequencing, amplified rDNA restriction analysis of the rrn operon, DNA-DNA hybridization homology and analysis of low-molecular-mass RNA species, it is concluded that the group of strains that specifically nodulate sulla consists of a coherent set of isolates that differ from previously described rhizobia to an extent that warrants the constitution of the species boundary. The name Rhizobium sullae sp. nov. is proposed, with isolate 1S123T (=USDA 4950T = DSM 14623T) as the type strain.

  • metabolic properties stress tolerance and macromolecular profiles of rhizobia nodulating Hedysarum coronarium
    Journal of Applied Microbiology, 1998
    Co-Authors: P Struffi, Andrea Squartini, Sergio Casella, Alessio Giacomini, Viviana Corich, Ammar Benguedouar, M P Nuti
    Abstract:

    The drought-tolerant legume Hedysarum coronarium is a Mediterranean species valued as a forage crop for its high performance in stressful conditions. The plant shows peculiar capabilities of nodulating above pH 9 and thriving in highly calcareous soils. With the aim of providing an adequate characterization of its bacterial symbiotic partner, a study was undertaken, approaching from several viewpoints the physiology and structural features of bacteria isolated from nodules of H. coronarium. Tests involved trophic capabilities on different carbon and nitrogen sources, vitamin requirements, and resistance to factors including antibiotics, heavy metals, salinity, pH, and temperature. Enzyme activities, including those of cellulase, pectinase, urease, beta-galactosidase, nitrate and nitrite reductase, were evaluated. The DNA G + C percentage content was determined. Species-specific bacteriophages were isolated and a strain-typing grid established. In order to characterize further and fingerprint the different Rhizobium 'hedysari' isolates, electrophoretic pattern of proteins, plasmid DNA, and digested genomic DNA (in pulsed-field gel separation) were compared. Adansonian taxonomy yielded similarity clusters of the different isolates.

G C Waghorn - One of the best experts on this subject based on the ideXlab platform.

  • the effect of diet fed to lambs on subsequent development of trichostrongylus colubriformis larvae in vitro and on pasture
    Veterinary Parasitology, 2002
    Co-Authors: J H Niezen, G C Waghorn, T Graham, J L Carter, D M Leathwick
    Abstract:

    Abstract Contrasting herbage diets were fed to lambs to evaluate their effect on subsequent development of Trichostrongylus colubriformis larvae in faeces and on pasture. The diets had either no condensed tannin (CT), lucerne (Medicago sativa cv. Otaio), white clover (Trifolium repens cv. Tahora), or had moderate to high concentrations of CT, sulla (Hedysarum coronarium cv. Grassland Aokau), Lotus corniculatus (cv. Grasslands Goldie), L. pedunculatus (cv. Grassland Maku), Dorycnium pentophyllum, and Dorycnium rectum. Trials were carried out in summer (warm) and in autumn (cool and moist). In summer, egg viability was evaluated in vitro with egg hatch and larval development assays. In both seasons faeces were placed on pasture to compare recovery of eggs and larvae from faeces and larvae from herbage on the high and low fertility farmlets on the AgResearch Ballantrae Hill Country Research Station. D. rectum and D. pentophyllum diets decreased (P

  • the effect of feeding sulla Hedysarum coronarium or lucerne medicago sativa on lamb parasite burdens and development of immunity to gastrointestinal nematodes
    Veterinary Parasitology, 2002
    Co-Authors: J H Niezen, W.a.g. Charleston, G C Waghorn, H A Robertson, D Shelton, R S Green
    Abstract:

    Two experiments investigated the efficacy of the legume Hedysarum coronarium (sulla), which contains condensed tannins (CTs), for reducing gastrointestinal nematode infections relative to lucerne. Experiment 1 was aimed to show whether the lower faecal egg count (FEC) and larval establishment previously reported in lambs grazing sulla were due to direct effects of the forage on Ostertagia circumcincta and Trichostrongylus colubriformis or were mediated through an enhanced immune response. Experiment 2 evaluated the impact of feeding sulla relative to feeding lucerne (Medicago sativa), before, at, or after larval challenge on subsequent FECs and nematode burdens. In experiment 1, 64 Romney lambs were fed either freshly cut lucerne or sulla (32 lambs per herbage) for the duration of the trial. Within each herbage there were four treatment groups (n=8 per group). Initial levels of immunity were assessed in uninfected (UN) lambs which were maintained parasite-free until challenged with 15,000 O. circumcincta and 15,000 T. colubriformis larvae on day 63, and slaughtered on day 81. The other three treatment groups were trickle-infected with each of 5000 O. circumcincta and 5000 T. colubriformis larvae three times per week from day 1 to 35. Non-steroid infected (CONTROL) and steroid-treated (STER) groups were treated with anthelmintic on day 49 and challenged with 15,000 O. circumcincta and 15,000 T. colubriformis on day 63 and slaughtered on day 81. The STER lambs were given dexamethasone trimethylacetate from day 49 to 81 to determine effects of immunity on parasite infection. From day 35 an establishment group (EST) on each herbage was fed a common pelleted lucerne diet and slaughtered on day 56 to determine nematode establishment during trickle-infection. Diet did not affect FECs but feeding lucerne increased (P<0.05) numbers of T. colubriformis in CONTROL lambs compared to those fed sulla. O. circumcincta numbers were lower (P<0.05) in UN lambs fed sulla than lucerne. The sulla diet was associated with higher (P<0.05) antibody titres against secretory–excretory antigens to adult O. circumcincta and to adult and larval T. colubriformis, so there appeared to be some immunogenic response to the sulla diet but effects upon T. colubriformis numbers were not significant. The second experiment involved 48 Romney lambs grazing conventional pasture which were infected with 10,000 each of O. circumcincta and T. colubriformis larvae either 7 days before, 7 days after, or at the time they commenced grazing either sulla or lucerne. Lambs which grazed sulla had lower (P<0.05) FEC and lower (P<0.05) O. circumcincta burdens than lambs which grazed lucerne but timing of infection had no effect on FEC or worm burdens. T. colubriformis numbers were not affected by treatment or herbage. In conclusion, the sulla diet resulted in lower O. circumcincta numbers compared to lucerne outdoors and some evidence of an immunogenic response was obtained indoors. However, neither the herbage nor the immunogenic response reduced T. colubriformis numbers in either experiment.

  • an evaluation of sulla Hedysarum coronarium with pasture white clover and lucerne for lambs
    Proceedings of the New Zealand Society of Animal Production, 2002
    Co-Authors: J L Burke, G C Waghorn, I M Brookes
    Abstract:

    Pasture-based diets restrict animal performance, due to limitations in voluntary feed intake and release of nutrients during digestion failing to meet nutrient requirements. Opportunities for improving the efficiency of pasture utilisation include the addition of a soluble carbohydrate source to enable an improved capture of ammonia by rumen bacteria, or the inclusion of condensed tannins (CT) to reduce protein degradation. A feed evaluation trial was conducted at AgResearch Grasslands to investigate the ability of sulla, a forage containing high concentrations of soluble carbohydrate and CT, to complement pasture and legume species. Fifty-six weaned ram lambs were allocated to seven diets: pasture (80% ryegrass and 20% white clover), white clover, lucerne, sulla, and 50:50 mixtures (DM basis) of pasture:sulla, white clover:sulla and lucerne:sulla. Lambs fed sulla, white clover, white clover:sulla and lucerne:sulla had the most rapid daily gains (256-263 g/day) while lambs fed pasture gained 105 g/day, respectively. Wool growth was influenced by diet. Sulla added to pasture, white clover and lucerne diets significantly reduced rumen ammonia concentrations and acetate:propionate ratios in lambs. Lamb performance can be improved by combining sulla with pasture and lucerne, and rumen parameters can be used to explain animal performance differences.

  • the effect of condensed tannins from seven herbages on trichostrongylus colubriformis larval migration in vitro
    Folia Parasitologica, 2000
    Co-Authors: A L Molan, G C Waghorn, W. C. Mcnabb
    Abstract:

    The effects of condensed tannins (CT) extracted from seven forages on the motility of the economically important nematode, Trichostrongylus colubriformis (Giles, 1892), were evaluated by using a larval migration inhibition (LMI) assay. The assay involved incubation of third stage (L3) exsheathed T. colubriformis larvae with CT extracted from Lotus pedunculatus, Lotus corniculatus, sulla (Hedysarum coronarium), sainfoin (Onobrychis viciifolia), Dorycnium rectum, Dorycnium pentaphyllum and dock (Rumex obtusifolius) and measurement of larval migration through nylon mesh with a 20µm pore size. At 100 µg ml -1 , CT from L. pedunculatus, L. corniculatus, sulla, sainfoin, D. rectum, D. pentaphyllum and dock inhibited 20%, 10%, 15%, 25%, 28%, 32% and 27% of the larvae, respectively from passing through the sieves compared to controls (no CT added). At 1000 µg CT ml -1 , CT purified from D. pentaphyllum had the highest inhibitory activity (63%) against 1-month old larvae followed by sainfoin (59%), L. pedunculatus (57%), D. rectum (53%), dock (50%), sulla (40%) and L. corniculatus (37%). Seven-month old larvae were more sensitive to the action of CT than 1-month old larvae (P < 0.001). Addition of 2 µg polyethylene glycol ((PEG) per µg CT; to remove the effect of CT) eliminated 81-93% of the CT activity (P < 0.001) compared to incubations without PEG. The impact of CT on larval migration suggests a possible role for these plants in ruminant diets as a means to reduce dependence upon proprietary anthelmintics.

  • effect of condensed tannins in birdsfoot trefoil lotus corniculatus and sulla Hedysarum coronarium on body weight carcass fat depth and wool growth of lambs in new zealand
    New Zealand Journal of Agricultural Research, 1999
    Co-Authors: G B Douglas, A G Foote, G C Waghorn, M Stienezen, R W Purchas
    Abstract:

    Abstract The effects of dietary condensed tannins (CT) on growth and performance of young male weaned lambs were measured during a 4‐month grazing trial when either birdsfoot trefoil (Lotus corniculatus) cv. Grasslands Goldie or sulla (Hedysarum coronarium) cv. Grasslands Aokau were fed. Each legume was offered at restricted and ad libitum allowances and the effects of CT were determined by giving half the lambs in each treatment a twice‐daily drench of polyethylene glycol (PEG; mol wt 3350) to deactivate the CT. Both agronomic and animal performance characteristics were recorded. Sulla had higher (P < 0.01) pre‐grazing herbage masses than birdsfoot trefoil (11.6 cf. 7.1 t DM ha−1) and sulla stem (<6 mm diam.) was eaten, in contrast to birdsfoot trefoil where stem was rejected by the lambs. The sulla and birdsfoot trefoil diets had similar protein concentrations in the DM, but sulla had a higher concentration of total CT (88 cf. 50 g CT kg1 DM) and less structural carbohydrate (189 cf. 328 g kg−1 DM) rela...

Dragan Bubalo - One of the best experts on this subject based on the ideXlab platform.

  • riboflavin and lumichrome in dalmatian sage honey and other unifloral honeys determined by lc dad technique
    Food Chemistry, 2012
    Co-Authors: Carlo Ignazio Giovanni Tuberoso, Ersilia Bifulco, Francesca Congiu, Igor Jerkovic, Zvonimir Marijanovic, Dragan Bubalo
    Abstract:

    Riboflavin (vitamin B2) and its metabolite lumichrome were quantified in 117 samples from 11 unifloral honeys types (Arbutus unedo L., Asphodelus microcarpus Salzm. et Viv., Citrus spp., Eucalyptus spp., Hedysarum coronarium L., Castanea sativa L. honeydew, Mentha spp., Paliurus spina-christi., Salix spp., Salvia officinalis L., Satureja spp.). The quantification of these two compounds was performed by LC–DAD method which does not require sample purification. The proposed method in our study has low limits of detection and quantification, very good linearity in a large concentration range and very good precision. It allows simultaneous determination of 5-hydroxymethylfurfural (HMF) and known chemical biomarkers of unifloral honeys such as abscisic acid diastereomers, homogentisic acid, methyl syringate and kynurenic acid. No statistical correlation was observed between riboflavin and lumichrome content. Although, the concentration of vitamin B2 in honey may be too low (<6.1 mg/kg) to generate interest in the field of nutrition, the presence of its main metabolite lumichrome may be useful to determine the botanical origin of certain unifloral honeys. In fact, the analysis of 11 unifloral honey types showed that Dalmatian sage (S. officinalis L.) honey is characterised by unusual high levels of lumichrome (20.2 ± 2.6 mg/kg). The botanical origin of lumichrome from sage flower was assessed by analysing bee-stomach extracts. Other analytical parameters, such as total phenols, antioxidant and antiradical activities, HMF and diastase activity were studied in Dalmatian sage honey.

  • Riboflavin and lumichrome in Dalmatian sage honey and other unifloral honeys determined by LC–DAD technique
    Food chemistry, 2012
    Co-Authors: Carlo Ignazio Giovanni Tuberoso, Igor Jerković, Ersilia Bifulco, Zvonimir Marijanović, Francesca Congiu, Dragan Bubalo
    Abstract:

    Riboflavin (vitamin B2) and its metabolite lumichrome were quantified in 117 samples from 11 unifloral honeys types (Arbutus unedo L., Asphodelus microcarpus Salzm. et Viv., Citrus spp., Eucalyptus spp., Hedysarum coronarium L., Castanea sativa L. honeydew, Mentha spp., Paliurus spina-christi., Salix spp., Salvia officinalis L., Satureja spp.). The quantification of these two compounds was performed by LC–DAD method which does not require sample purification. The proposed method in our study has low limits of detection and quantification, very good linearity in a large concentration range and very good precision. It allows simultaneous determination of 5-hydroxymethylfurfural (HMF) and known chemical biomarkers of unifloral honeys such as abscisic acid diastereomers, homogentisic acid, methyl syringate and kynurenic acid. No statistical correlation was observed between riboflavin and lumichrome content. Although, the concentration of vitamin B2 in honey may be too low (

Salvador Nadal - One of the best experts on this subject based on the ideXlab platform.

  • collection characterization and evaluation of wild Hedysarum coronarium l populations from andalusia southern spain
    Australian Journal of Crop Science, 2013
    Co-Authors: Eva Maria Cordoba, Belen Roman, Salvador Nadal, Clara Isabel Gonzalezverdejo
    Abstract:

    Sulla (Hedysarum coronarium L.) is a short-lived perennial legume native to the Mediterranean basin. This legume plays an important role in forage production due to its high protein content, moderate levels of condensed tannins and a multifunctional agriculture. In Spain, like other countries, different factors are causing the destruction of natural ecosystems and are thus leading to a loss of genetic resources. Therefore, before these resources are irreversibly lost, we collected natural sulla populations from different Andalusian (southern Spain) environments. Additionally, several natural populations and three commercial varieties included as controls, were evaluated and compared for pheno-morphological and agronomic characteristics. Twenty-six accessions were collected, and statistical analysis indicated the presence of genetic variability within the species and between the populations for both the pheno-morphological and agronomic traits studied. The agronomic attributes of several native populations were more pronounced than or similar to the commercial accessions. In Principal Component Analysis, the first two components explained over 80% of genetic variation. Principal Component 1 was positively influenced by the internode number of the principal stem, the diameter of principal stem and the length of the principal stem. Principal Component 2 was positively influenced by the number of inflorescences and by end of flowering and negatively influenced by the leaf area. The results in this study suggest that the characteristics widely vary and have been identified as sources for use in forage or pasture.

  • selection of reference genes in Hedysarum coronarium under various stresses and stages of development
    Analytical Biochemistry, 2011
    Co-Authors: Eva Maria Cordoba, Jose V Die, Salvador Nadal, Clara Isabel Gonzalezverdejo, Belen Roman
    Abstract:

    The cultivation of Hedysarum coronarium has generated interest recently for its high yield as a fodder crop, its high protein content, and the presence of condensed tannins in its leaf and stem tissues. Gene expression studies can lead to a better understanding of the biological processes of live organisms. Specifically, reverse transcription followed by quantitative polymerase chain reaction (PCR) represents the most powerful technology for comparing the expression profiles of target genes. The use of reference genes as internal controls to normalize messenger RNA (mRNA) levels is a requirement of quantitative PCR (qPCR). Few studies on reference genes have been performed in plants, and no studies have been performed in H. coronarium. Therefore, the aim of this study was to identify and evaluate reference genes to use in qPCR in H. coronarium. Sulla tissues under two conditions of abiotic stress and at various stages of development were studied to determine adequate reference genes. To optimize the identity and number of reference genes, geNorm and BestKeeper software programs were employed. Based on the results of both analyses, TUA1, TUA2, and UBQ were found to be the most suitable reference genes, and the combination of these three genes was suggested for the accurate normalization of gene expression in sulla tissues.

  • first report of orobanche crenata on sulla Hedysarum coronarium in andalusia southern spain
    Plant Disease, 2008
    Co-Authors: Eva Maria Cordoba, C I Gonzalezverdejo, Jose V Die, Belen Roman, Salvador Nadal
    Abstract:

    Crenata broomrape (Orobanche crenata Forsk.), an obligate chlorophyll-lacking root parasite, is the major constraint for growing legume crops in infested soils in southern Spain. Peas (Pisum sativum L), faba beans (Vicia faba L.), and narbon bean (Vicia narbonensis L.) are seriously affected (1,2,4). However, no information is available regarding its ability to attack sulla (Hedysarum coronarium L.), which is an important fodder legume grown in rain-fed conditions, yielding as much as 10,000 kg/ha of dry matter. In 2008, we found broomrape shoots infecting 4 to 5% of sulla plants in a trial field (two land races, P-26 and P-3, in a 500-m2 area) in Cordoba (Andalusia, southern Spain). The shoots developed numerous fertile flowering stalks throughout the field. The previous crop, narbon bean, was heavily infected during 2007 by O. crenata. Infection of sulla plants was confirmed by digging up the plant to verify the attachment of the broomrape plant to the sulla roots. The level of infection was low with on...

J H Niezen - One of the best experts on this subject based on the ideXlab platform.

  • the effect of diet fed to lambs on subsequent development of trichostrongylus colubriformis larvae in vitro and on pasture
    Veterinary Parasitology, 2002
    Co-Authors: J H Niezen, G C Waghorn, T Graham, J L Carter, D M Leathwick
    Abstract:

    Abstract Contrasting herbage diets were fed to lambs to evaluate their effect on subsequent development of Trichostrongylus colubriformis larvae in faeces and on pasture. The diets had either no condensed tannin (CT), lucerne (Medicago sativa cv. Otaio), white clover (Trifolium repens cv. Tahora), or had moderate to high concentrations of CT, sulla (Hedysarum coronarium cv. Grassland Aokau), Lotus corniculatus (cv. Grasslands Goldie), L. pedunculatus (cv. Grassland Maku), Dorycnium pentophyllum, and Dorycnium rectum. Trials were carried out in summer (warm) and in autumn (cool and moist). In summer, egg viability was evaluated in vitro with egg hatch and larval development assays. In both seasons faeces were placed on pasture to compare recovery of eggs and larvae from faeces and larvae from herbage on the high and low fertility farmlets on the AgResearch Ballantrae Hill Country Research Station. D. rectum and D. pentophyllum diets decreased (P

  • the effect of feeding sulla Hedysarum coronarium or lucerne medicago sativa on lamb parasite burdens and development of immunity to gastrointestinal nematodes
    Veterinary Parasitology, 2002
    Co-Authors: J H Niezen, W.a.g. Charleston, G C Waghorn, H A Robertson, D Shelton, R S Green
    Abstract:

    Two experiments investigated the efficacy of the legume Hedysarum coronarium (sulla), which contains condensed tannins (CTs), for reducing gastrointestinal nematode infections relative to lucerne. Experiment 1 was aimed to show whether the lower faecal egg count (FEC) and larval establishment previously reported in lambs grazing sulla were due to direct effects of the forage on Ostertagia circumcincta and Trichostrongylus colubriformis or were mediated through an enhanced immune response. Experiment 2 evaluated the impact of feeding sulla relative to feeding lucerne (Medicago sativa), before, at, or after larval challenge on subsequent FECs and nematode burdens. In experiment 1, 64 Romney lambs were fed either freshly cut lucerne or sulla (32 lambs per herbage) for the duration of the trial. Within each herbage there were four treatment groups (n=8 per group). Initial levels of immunity were assessed in uninfected (UN) lambs which were maintained parasite-free until challenged with 15,000 O. circumcincta and 15,000 T. colubriformis larvae on day 63, and slaughtered on day 81. The other three treatment groups were trickle-infected with each of 5000 O. circumcincta and 5000 T. colubriformis larvae three times per week from day 1 to 35. Non-steroid infected (CONTROL) and steroid-treated (STER) groups were treated with anthelmintic on day 49 and challenged with 15,000 O. circumcincta and 15,000 T. colubriformis on day 63 and slaughtered on day 81. The STER lambs were given dexamethasone trimethylacetate from day 49 to 81 to determine effects of immunity on parasite infection. From day 35 an establishment group (EST) on each herbage was fed a common pelleted lucerne diet and slaughtered on day 56 to determine nematode establishment during trickle-infection. Diet did not affect FECs but feeding lucerne increased (P<0.05) numbers of T. colubriformis in CONTROL lambs compared to those fed sulla. O. circumcincta numbers were lower (P<0.05) in UN lambs fed sulla than lucerne. The sulla diet was associated with higher (P<0.05) antibody titres against secretory–excretory antigens to adult O. circumcincta and to adult and larval T. colubriformis, so there appeared to be some immunogenic response to the sulla diet but effects upon T. colubriformis numbers were not significant. The second experiment involved 48 Romney lambs grazing conventional pasture which were infected with 10,000 each of O. circumcincta and T. colubriformis larvae either 7 days before, 7 days after, or at the time they commenced grazing either sulla or lucerne. Lambs which grazed sulla had lower (P<0.05) FEC and lower (P<0.05) O. circumcincta burdens than lambs which grazed lucerne but timing of infection had no effect on FEC or worm burdens. T. colubriformis numbers were not affected by treatment or herbage. In conclusion, the sulla diet resulted in lower O. circumcincta numbers compared to lucerne outdoors and some evidence of an immunogenic response was obtained indoors. However, neither the herbage nor the immunogenic response reduced T. colubriformis numbers in either experiment.

  • growth and gastrointestinal nematode parasitism in lambs grazing either lucerne medicago sativa or sulla Hedysarum coronarium which contains condensed tannins
    The Journal of Agricultural Science, 1995
    Co-Authors: J H Niezen, W.a.g. Charleston, T S Waghorn, G C Waghorn
    Abstract:

    Two grazing experiments were undertaken to evaluate the effects of sulla (Hedysarum coronarium) which contains condensed tannins (CT) and lucerne (Medicago sativa), which does not contain CT, on the performance of parasitized and non-parasitized lambs. The work was carried out near Palmerston North, New Zealand in 1992 and 1993. Experiment 1 used lambs which were either genetically 'conventional' or 'resistant' to gastrointestinal nematodes and which had a naturally acquired heavy parasite burden (faecal egg count (FEC) 1300-2500 eggs per gram faeces (epg)). They were either drenched to remove all the parasites or remained undrenched when allocated to pure swards of either sulla or lucerne for the 28-day experimental period. Liveweight gains of drenched lambs were higher with sulla (mean 302 g/day) than with lucerne (mean 245 g/day; P < 0.02) and rates of gain were not reduced (P = 0.10) by genetic resistance to nematodes. Undrenched lambs had mean faecal egg counts of 1090-2220 epg after 28 days, with higher counts in lambs grazing lucerne than in those grazing sulla (P < 0.05). Lambs grazing lucerne also had a much lower average daily gain (ADG) (mean 50 g/day) than those grazing sulla (mean 206 g/day; P < 0.0001). Resistant lambs had reduced (P = 0.07) ADG in the sulla treatment only. In Expt 2, lambs with a relatively low worm burden (average FEC 250 epg) were either drenched to remove all worms or dosed with 20 000 Trichostrongylus colubriformis infective larvae and grazed on pure sulla or lucerne swards for 42 days. Drenched lambs had a similar liveweight gain (mean 190 g/day) and wool growth when grazing either sulla or lucerne. Undrenched lambs grazing sulla had a greater ADG (mean 129 g/day) than those grazing lucerne (mean -39 g/day; P < 0.0001) and a higher rate of wool growth from mid-side patches (P < 0.009) and larger wool fibre diameter (P < 0.05) than those grazing lucerne. Undrenched lambs grazing sulla had lower FECs (P < 0.05) on days 14, 21, 35 and 42 than those grazing lucerne and lower (P < 0.05) Trichostrongylus colubriformis worm burdens at slaughter. Undrenched lambs had less perineal faecal contamination when grazing sulla rather than lucerne. Parasite-induced anorexia was evident in the lambs grazing lucerne but not in those grazing sulla. These findings demonstrate that the performance of lambs infected with nematode parasites can vary substantially when given feeds of a similar chemical composition. The superior performance of lambs grazing sulla was probably caused by condensed tannins, which decrease protein degradation in the rumen and can increase post-ruminal protein availability.