Thermoregulatory Effects of Ergovaline Isolated from Endophyte-Infected Tall Fescue Seed on Rats

Zhang, Qinggen; Spiers, Donald E.; Rottinghaus, George E.; Garner, G. B.

doi:10.1021/jf00040a022

Cited by 16 publications

(10 citation statements)

References 20 publications

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“…Consistent with previous studies (Zhang et al, 1994;Spiers et al, 1995), thermoneutral hypothermia was observed when rats were fed the endophyte-infected diet in the present study at 21 1C. Core temperature was reduced by more than 0.3 1C after several days on the endophyte-infected diet, and this was similar to previous studies in our lab (Settivari et al, 2006).…”

Section: Core Body Temperature and Motor Activitysupporting

confidence: 93%

Adaptive responses to fescue toxicosis under thermoneutral and heat stress conditions

Kishore

Eichen

Spiers

2012

Journal of Thermal Biology

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Section: Core Body Temperature and Motor Activitysupporting

confidence: 93%

Adaptive responses to fescue toxicosis under thermoneutral and heat stress conditions

Kishore

Eichen

Spiers

2012

Journal of Thermal Biology

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“…This lack of response is similar to that seen in long-term studies by others (Osborn et al, 1992;Aldrich et al, 1993). In addition, Zhang et al (1994) showed that rats injected with ergovaline at TN did not exhibit an acute change in tail temperature that might suggest a reduction in blood fl ow to this region. Lack of change in T re and T skin of cattle in the present study when fed the E+ diet at TN would suggest that body temperature response, in general, is not a sensitive marker under this environmental condition.…”

Section: Thermoneutral Responsesupporting

confidence: 88%

Use of different levels of ground endophyte-infected tall fescue seed during heat stress to separate characteristics of fescue toxicosis1

Spiers

Wax

Eichen

et al. 2012

Journal of Animal Science

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Studies of fescue toxicosis using whole seed diets show reduced feed intake and thermoregulatory ability, but much of the seed passes undigested through the animal. Cattle were fed ground tall fescue seed at different levels to potentially facilitate digestion and absorption of toxins and identify toxin sensitivity for major characteristics of the condition [i.e., hyperthermia, reduced feed intake (FI), reduced blood prolactin]. Steers (n = 18; 350 kg BW) were housed in the Brody Climatology Laboratory at thermoneutrality (TN; 19°C) and randomly assigned to daily diet treatments with either ground endophyte-infected [E+; low and high doses at 20 and 40 μg ergovaline/(kg BW/d), respectively] or endophyte-free [E-; control at 0 μg ergovaline/(kg BW/d)] tall fescue seed. After 12 d at TN, animals received 2 d of transition to heat stress (HS; 36°C daytime, 25°C nighttime) and maintained for 14 more days. Cattle were fed twice daily at 0800 and 1600 h, with water ad libitum. Feed intake was measured at 0700 h, with skin and rectal temperatures, and respiration rate at 0600, 1100, 1600, and 2100 h. Blood was sampled on selected days for prolactin and leptin determinations. Steers fed ground E+ diet decreased (P ≤ 0.0001) FI below controls at TN, with no dose effect. Maximum FI reduction with E+ treatment was 25% at TN, with an additional 46% decrease during HS (P ≤ 0.05). By the end of HS, E+ FI increased (P > 0.05) to that of E-, suggesting recovery. Prolactin was reduced (P ≤ 0.05) in high E+ cattle below controls at study end. Leptin blood concentrations were unaffected by E+ treatment (P > 0.05) but was reduced (P ≤ 0.05) by the end of HS. Pattern of rectal temperature response to HS showed a more rapid initial increase and decline for both E+ groups compared with controls (P ≤ 0.05). Skin temperature was the only variable that identified E+ dose differences. Although there were no treatment differences at TN, skin temperature was lower (P ≤ 0.05) for high E+ steers compared with controls during HS when air temperature was reduced each day. In general, FI was more responsive to E+ toxins than body temperature or blood prolactin, declining even at TN and exhibiting dynamic activity during HS. Although body temperature response to E+ toxins appears to stabilize during HS, this is misleading as rapid change in air temperature exposes effects on skin temperature.

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“…air Few studies have been conducted under controlled environmental conditions to verify these shifts and determine mechanisms of action. Adult rats have been tested in environmental chambers at 7\r values known to represent cold (7-9°C), thermoneutral (22°C), and hot (31-33°C) conditions following a single intraperitoneal injection of ergovaline (15|ig/kg BW; Spiers et al, 1995;Zhang et al, 1994). Hyperthermia in the hot environment was preceded by a reduction in tail skin temperature with no shift in heat production, indicating that the cause was a reduction in cutaneous heat loss (Spiers et al, 1995).…”

Section: Thermal Response Heat Tolerance and Stressmentioning

confidence: 99%

Physiological Basis of Fescue Toxicosis

Strickland

Aiken

Spiers

et al. 2015

Agronomy Monographs

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Tall fescue toxicosis continues to be a major syndrome in temperate climates of the world in terms of economic loss to animal producers. Studies with forage-fed animals over the past three decades have provided insight concerning the pathophysiological effects of the alkaloids present in tall fescue [Lolium arundinaceum (Schreb.) DarbyshJ infected with the fungal endophyte Neotyphodium coenophialum (Morgan-Jones and Gams) Glenn, Bacon, and Hanlin. To provide the reader a general understanding of the overall problem, we present a detailed discussion of the clinical signs of fescue toxicosis, the proposed toxicants, and projected solutions to this costly disease condition of ungulates. We also explore the physiological mechanisms proposed to be involved in the expression of the syndrome. Finally, we offer our suggestions for future research efforts in this arena and the potential impact of these approaches. T all fescue is an economically important cool-season perennial forage grass covering about 15 million ha in the United States alone (Buckner et al., 1979) and many more in continents outside North America (see Chapter 3, Hannaway et alv 2009, this publication). The vast majority of the tall fescue in the United States is grown within the transition zone of the eastern and central part of the country. With the development of novel nontoxic endophytes, tall fescue is again becoming increasingly popular for pastures in New Zealand and Australia. The wide distribution of tall fescue has been attributed to its symbiotic relationship (see Chapter 14, Christensen and Voisey, 2009, this publication) with the endophytic fungus Neotyphodium coenophialum (Glenn et al., 1996). Although beneficial to

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Thermoregulatory Effects of Ergovaline Isolated from Endophyte-Infected Tall Fescue Seed on Rats

Cited by 16 publications

References 20 publications

Adaptive responses to fescue toxicosis under thermoneutral and heat stress conditions

Adaptive responses to fescue toxicosis under thermoneutral and heat stress conditions

Use of different levels of ground endophyte-infected tall fescue seed during heat stress to separate characteristics of fescue toxicosis1

Physiological Basis of Fescue Toxicosis

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