High nitrogen supply and carbohydrate content reduce fungal endophyte and alkaloid concentration in <i>Lolium perenne</i>

Rasmussen, Susanne; Parsons, A. J.; Bassett, Shalome A.; Christensen, Michael J.; Hume, D. E.; Johnson, Linda J.; Johnson, Richard D.; Simpson, Wayne R.; Stacke, Christina; Voisey, Christine R.; Xue, Hong; Newman, Jonathan A.

doi:10.1111/j.1469-8137.2006.01960.x

Cited by 208 publications

(236 citation statements)

References 63 publications

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“…The concentration of feed WSC was analysed following the method described by Rasmussen et al (2007). Oven dried feed, acidified urine and oven dried faeces were analysed for N concentration using an Elementar (Variomax CN Analyser, Elementar Analysensysteme, Germany).…”

Section: Methodsmentioning

confidence: 99%

The effect of dietary water soluble carbohydrate to nitrogen ratio on nitrogen partitioning and isotopic fractionation of lactating goats offered a high-nitrogen diet

Cheng

Edwards

Dewhurst

et al. 2016

Animal

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The objective of this study was to investigate the relationship between nitrogen (N) partitioning and isotopic fractionation in lactating goats consuming diets with a constant high concentration of N and increasing levels of water soluble carbohydrate (WSC). Eight lactating goats were offered four different ratios of WSC : N in the diet. A two-period incomplete cross-over design was used, with two goats assigned to each treatment in each period. N balance measurements were conducted, with measurement of feed N intake and total output of N in milk, faeces and urine. Treatment, period and infusion effects were tested using general ANOVA; the relationships between variables were analysed by linear regression. Dietary treatment and period had significant effects on dry matter (DM) intake (g/day). DM digestibility (g/kg DM) and N digestibility (g/kg N) increased as the ratio of WSC : N increased in the diet. No treatment effect was observed on milk urea N concentration (g/l) or urinary excretion of purine derivatives (mM/day). Although dietary treatment and period had significant effects on N intake, the change of N intake was small; no effect was observed for N partitioning among faeces, milk and urine. Milk, plasma and faeces were enriched in 15 N compared with feed, whilst urine was depleted in 15 N relative to feed. No significant relationship was established between N partitioning and isotopic fractionation. This study failed to confirm the potential to use N isotopic fractionation as an indicator of N partitioning in dairy goats when diets provided N in excess to requirements, most likely because the range of milk N output/N intake and urinary N output/N intake were narrow.Keywords: nitrogen utilisation, urea nitrogen, stable isotopic discrimination, dairy goats Implications Current approaches to determine the sole contribution of water soluble carbohydrate (WSC) to animal performance is limited by the fact that chemical components (e.g. nitrogen (N) and WSC) in feed are not independent, at least in pasture. Therefore, this study was designed to test the effect of increasing dietary WSC concentration, at a consistently high N concentration, on N utilisation and isotopic fractionation. Results showed inclusion of WSC neither improved microbial protein synthesis nor N utilisation. Further, the study failed to confirm the use of N isotopic fractionation as a simple indicator of N partitioning.

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Section: Methodsmentioning

confidence: 99%

The effect of dietary water soluble carbohydrate to nitrogen ratio on nitrogen partitioning and isotopic fractionation of lactating goats offered a high-nitrogen diet

Cheng

Edwards

Dewhurst

et al. 2016

Animal

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“…The grass species and endophytic fungal and bacterial symbiosis has been studied in considerable detail in a number of species. [65][66][67][68] However, the involvement of bacterial endophytes and epiphytic root colonizers which are specifically associated with roots of exotic P. australis needs to be unraveled. Further, the testing of this hypothesis should answer the questions such as whether rhizospheric microbes involved in triggering the invasive behavior of P. australis.…”

Section: Are There Other Partners In Crime?mentioning

confidence: 99%

Genetics, novel weapons and rhizospheric microcosmal signaling in the invasion ofPhragmites australis

Rudrappa

Bais

2008

Plant Signaling & Behavior

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Chemical communication and perception strategies between plants are highly sophisticated but are only partly understood. Among the different interactions, the suppressive interaction of a class of chemicals released by one plant through root exudates against the neighbouring plants (allelopathy) have been implicated in the invasiveness of many exotic weedy species. Phragmites australis (common reed) is one of the dominant colonizers of the North American wetland marshes and exhibits invasive behavior by virtually replacing the entire native vegetation in its niche. Recently, by adopting a systematic bioassay driven approach we elucidated the role of root derived allelopathy as one of the important mechanisms by which P. australis exerts its invasive behavior. Additionally, our recent preliminary data indicates the involvement of rhizobacterial signaling in the invasive success of P. australis. A better understanding of biochemical weaponry used by P. australis will aid scientists and technologists in addressing the impact of root secretions in invasiveness of weedy species and thus promote a more informed environmental stewardship.

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“…However, tall fescue growing by a legume may have greater concentrations of alkaloids. Bacteria on the root nodules of legumes fix nitrogen and they may not only increase the nutritional value of nearby grasses, but the nitrogen they fix may provide a substrate to increase alkaloids in fescue (Arechavaleta et al, 1992, but see Rasmussen et al 2007). According to the carbon-nutrient balance hypothesis (Bryant et al, 1983), increased nitrogen availability can, simply by mass action, increase concentrations of nitrogenbased secondary compounds like alkaloids.…”

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confidence: 99%

Preference by sheep for endophyte-infected tall fescue grown adjacent to or at a distance from alfalfa

Friend

Provenza

Villalba

2015

Animal

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Two experiments were conducted to assess preference by sheep for endophyte-infected tall fescue growing in monoculture at least 5 m away from alfalfa (fescue-middle (FM)) over endophyte-infected tall fescue growing adjacent (0.2 to 1 m; fescue-alfalfa (FA)) to alfalfa (FA), and the effect of legume scent on preference for endophyte-infected tall fescue. In Experiment 1, 10 six-month-old lambs were offered for 12 days a choice of freshly harvested FA and FM. On days 13 and 14, lambs were offered the same choice, except cages (to allow access only to scent) containing freshly harvested alfalfa were put in the feeders containing FA, whereas cages containing freshly harvested FM were included with the feeders containing FM. Forage intake was measured 1 h after feeding and at three consecutive 2-h intervals thereafter. FA contained greater ( P < 0.002) concentrations of the alkaloid ergovaline (360 ± 27 ppm) and CP (8 ± 0.4%) than FM (219 ± 27 ppm and 6 ± 0.4%, respectively). Lambs preferred ( P < 0.05) FA to FM during the 1 st hour of feeding, but the differences became smaller and disappeared in later feeding periods ( P < 0.005). Lambs offered FA with alfalfa scent or FM with FM scent preferred ( P < 0.05) FA but only on the 2 nd day. In Experiment 2, 10 six-month-old lambs were offered a choice of FM with cages (to allow access only to scent) containing freshly harvested alfalfa or FM for 8 days. During the following 4 days, FM in the cages was replaced with freshly harvested sainfoin. Preference was greater ( P < 0.05) for FM offered with alfalfa scent than for FM offered with FM scent only on days 4 and 8. When lambs were offered FM with alfalfa or sainfoin in cages, they preferred ( P < 0.05) tall fescue with sainfoin scent over fescue with alfalfa scent, but intake was variable across hours and days ( P < 0.001). It is concluded that (1) lambs adjusted their intake of and preference for FA and FM over successive feeding bouts within each day, likely owing to an attempt to balance intakes of nutrients and alkaloids and (2) olfactory cues influenced preference, but to a lesser extent than nutrients and alkaloids in endophyte-infected tall fescue.

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High nitrogen supply and carbohydrate content reduce fungal endophyte and alkaloid concentration in Lolium perenne

Cited by 208 publications

References 63 publications

The effect of dietary water soluble carbohydrate to nitrogen ratio on nitrogen partitioning and isotopic fractionation of lactating goats offered a high-nitrogen diet

The effect of dietary water soluble carbohydrate to nitrogen ratio on nitrogen partitioning and isotopic fractionation of lactating goats offered a high-nitrogen diet

Genetics, novel weapons and rhizospheric microcosmal signaling in the invasion ofPhragmites australis

Preference by sheep for endophyte-infected tall fescue grown adjacent to or at a distance from alfalfa

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