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Author: Jenny Katherine Bryant Publisher: ISBN: Category : Electronic dissertations Languages : en Pages : 181
Book Description
Fescue toxicosis may result from the intake of ergot alkaloids found in endophyteinfected (E+) tall fescue. The liver if the major organ involved in the pathology of fescue toxicosis, as it is the site where the toxic ergot alkaloids are metabolized. A study performed with rats consuming and E+ diet reported increased expression of Phase I detoxification enzymes and a decreased expression of antioxidants, to suggest an increase of cellular oxidative stress. This study was performed to determine if intake of E+ fescue had the same effect on the expression of detoxification enzymes and antioxidants in cattle. A second objective of this study was to examine changes in the hepatic transcriptome that occur when cattle consume E+ fescue. Missouri- (MO; n=10; 513.6±1.3 Kg BW) and Oklahoma- (OK; n=10; 552.8±12.0 Kg BW) derived Angus steers, maintained at 19-22°C (TN) air temperature for 8 days and then maintained at cycling heat stress for an additional 10 days (26°C night Ta; 36°C day Ta:HS). Cattle were fed diets containing either endophyte-free (E-) or E+ seed (30 [microgram] ergovaline/Kg BW/day) and feed intake (FI) was recorded daily. Blood and liver tissue samples were collected during pretreatment followed by blood samples at Day 4, 11, and 17 and liver tissue samples were collected again on Day 7 and 18. Consumption of E+ fescue resulted in significantly reduced (p!0.05) feed intake in both the TN and HS periods when compared to the E- group. There was also a significantly (p!0.05) lower serum prolactin concentration of E+ steers when compared to E- steers in both the TN and HS periods. These results confirm that E+ steers were experiencing the physiological conditions associated with fescue toxicosis. Real-time PCR was performed to determine expression of selected hepatic Phase I detoxification enzymes and specific antioxidant proteins. Illumina deep sequencing was performed on TN samples from selected fescue-naïve OK steers. Tiling of the sequences to a ~23,500 member reference allowed for the quantification of mRNA transcript abundance in each sample. Real-time PCR demonstrated that cattle consuming E+ fescue did not a significant change in the expression of Phase I detoxification enzymes or antioxidants. Illumina transcriptome analysis confirmed that E+ fescue did not have any significant effect on the expression of selected Phase I genes; however, there were 76 genes whose expression was significantly affected by E+ fescue, including a number of genes involved in !-oxidation of fatty acids, oxidative phosphorylation, Phase II detoxification, antioxidant activity and the stress response. Illumina deep sequencing aided in compiling a list of genes, which should undergo further study to identify the nature of their connection to the clinical signs of fescue toxicosis.
Author: Jenny Katherine Bryant Publisher: ISBN: Category : Electronic dissertations Languages : en Pages : 181
Book Description
Fescue toxicosis may result from the intake of ergot alkaloids found in endophyteinfected (E+) tall fescue. The liver if the major organ involved in the pathology of fescue toxicosis, as it is the site where the toxic ergot alkaloids are metabolized. A study performed with rats consuming and E+ diet reported increased expression of Phase I detoxification enzymes and a decreased expression of antioxidants, to suggest an increase of cellular oxidative stress. This study was performed to determine if intake of E+ fescue had the same effect on the expression of detoxification enzymes and antioxidants in cattle. A second objective of this study was to examine changes in the hepatic transcriptome that occur when cattle consume E+ fescue. Missouri- (MO; n=10; 513.6±1.3 Kg BW) and Oklahoma- (OK; n=10; 552.8±12.0 Kg BW) derived Angus steers, maintained at 19-22°C (TN) air temperature for 8 days and then maintained at cycling heat stress for an additional 10 days (26°C night Ta; 36°C day Ta:HS). Cattle were fed diets containing either endophyte-free (E-) or E+ seed (30 [microgram] ergovaline/Kg BW/day) and feed intake (FI) was recorded daily. Blood and liver tissue samples were collected during pretreatment followed by blood samples at Day 4, 11, and 17 and liver tissue samples were collected again on Day 7 and 18. Consumption of E+ fescue resulted in significantly reduced (p!0.05) feed intake in both the TN and HS periods when compared to the E- group. There was also a significantly (p!0.05) lower serum prolactin concentration of E+ steers when compared to E- steers in both the TN and HS periods. These results confirm that E+ steers were experiencing the physiological conditions associated with fescue toxicosis. Real-time PCR was performed to determine expression of selected hepatic Phase I detoxification enzymes and specific antioxidant proteins. Illumina deep sequencing was performed on TN samples from selected fescue-naïve OK steers. Tiling of the sequences to a ~23,500 member reference allowed for the quantification of mRNA transcript abundance in each sample. Real-time PCR demonstrated that cattle consuming E+ fescue did not a significant change in the expression of Phase I detoxification enzymes or antioxidants. Illumina transcriptome analysis confirmed that E+ fescue did not have any significant effect on the expression of selected Phase I genes; however, there were 76 genes whose expression was significantly affected by E+ fescue, including a number of genes involved in !-oxidation of fatty acids, oxidative phosphorylation, Phase II detoxification, antioxidant activity and the stress response. Illumina deep sequencing aided in compiling a list of genes, which should undergo further study to identify the nature of their connection to the clinical signs of fescue toxicosis.
Author: Sachin Bhusari Publisher: ISBN: Category : Electronic dissertations Languages : en Pages :
Book Description
Fescue toxicosis affects domestic animals grazing fescue pasture infected with the endophytic fungus, Neotyphodium coenophialum. Signs of fescue toxicosis include increased body temperature and respiration rate and decreased milk yield and reproductive performance. Laboratory mice also exhibit symptoms of fescue toxicosis as indicated by reduced growth rate and reproductive performance. Mice were used to study effects of fescue toxicosis on hepatic gene expression. Twenty-seven mice were randomly allocated to a diet containing either 50% endophyte-infected (E+) or endophyte-free (E- ) fescue seed for two wks under thermoneutral conditions. A two-stage ANOVA of microarray data identified thirty-six genes differentially expressed between mice fed E+ and E- diets. The E+ diet resulted in down-regulation of genes involved in sex-steroid pathway and in cholesterol and lipid metabolism. Genes coding for ribosomes and protein synthesis were up-regulated by the E+ diet. Mice were also used to study the effects of chronic heat stress on hepatic gene expression. Twenty-five mice were randomly allocated to either chronic heat stress (cHS; 34 " 1°C) or thermoneutral (TN; 24 " 1°C) conditions for a period of two wks from 47 to 60 d of age. A two-stage ANOVA of 1353 gene oligoarray data identified thirty genes as differentially expressed due to cHS. Genes involved in the anti-oxidant pathway were up-regulated due to cHS. Genes involved in generation of reactive oxygen radicals and a number of mitochondrial expressed genes were down-regulated by cHS. However, cHS did not produce an increase in oxidative stress induced mitochondrial DNA damage. Furthermore, effects of heat stress on changes in gene expression due to fescue toxicosis in mice liver were studied using DNA microarrays. Our goal was to characterize the differences in liver gene expression of mice exposed to chronic heat stress (cHS) and E+ when compared to mice fed E+ at TN. Mice were fed E+ diet under cHS (34 " 1°C; n = 13; E+cHS) or TN conditions (24 " 1°C; n = 14; E+TN) for a period of two wks between 47 to 60 d of age. Forty-one genes were differentially expressed between treatment groups. Genes coding for phase I detoxification and anti-oxidant pathway were up-regulated in E+cHS mouse liver. Key genes involved in de novo lipogenesis and lipid transport were also up-regulated. Finally, genes involved in DNA damage control and unfolded protein responses were down-regulated. In summary, mice fed an E+ diet at TN resulted in change in expression of genes involved in sex-steroid pathway while this pathway was not perturbed in mice exposed to cHS or to E+cHS treatments. Changes in expression of genes involved in lipid and cholesterol metabolism pathway occurred in mice exposed to E+ and to E+cHS treatment. Anti-oxidant gene expression changes occurred in mice exposed to cHS and to E+cHS, but not in E+ treated mice. Interestingly, gene expression changes involved in the detoxification pathway were seen only in mice exposed to combination of E+ and cHS. Biological pathways and gene expression changes identified in mouse liver due to E+, cHS, and E+cHS will help to understand molecular mechanisms by which fescue toxicosis and heat stress affects animals.
Author: Brandon Jermaine McClenton Publisher: ISBN: Category : Languages : en Pages : 98
Book Description
The objective of this study was to determine the effects of feeding endophyte-infected tall fescue seed to Angus steers on average daily gain, carcass characteristics, ergovaline concentration, lipid oxidation, hepatic enzyme activity, metmyoglobin reductase activity, and mitochondrial lipid composition. Animals were blocked into light, medium, and heavy body weight groups and were randomly assigned to either a KY31 seed treatment (6796 ppb ergovaline; 20 μg/kg BW; E+; n = 6) or a KY32 control ( 100 ppb; E-; n = 6). There was a 2- way treatment × time interaction effect on ADG (P
Author: Raja Sekhar Settivari Publisher: ISBN: Category : Electronic dissertations Languages : en Pages :
Book Description
Fescue toxicosis results from intake of toxins in fescue containing an endophytic fungus, Neotyphodium coenophialum. Time-related changes in rats associated with intake of an endophyte-infected fescue diet (E+) were evaluated under thermoneutral (TN), and both short- and long-term heat stress (HS) conditions. Short-term E+ intake decreased feed intake and growth rate under both conditions, whereas rats exhibited signs of adaptation during long-term exposure with better recovery occurring under TN conditions. Rats fed an E+ diet did not change core temperature during TN, but under HS conditions they exhibited a short-term increase in core temperature above control level. However, there was adaptive return of this temperature to TN level with long-term exposure. Short-term E+ intake at TN decreased serum glucose, urea nitrogen, alkaline phosphatase, and cholesterol; whereas long-term E+ intake under these conditions resulted in complete adaptation. In contrast, short-term E+ intake at HS did not affect serum biochemistry, while long-term intake decreased all the above mentioned serum parameters. Serum prolactin level was decreased during both short- or long-term TN and HS conditions. The E+ diet decreased hepatic antioxidant gene expression, with even greater reduction as a result of HS. Long-term E+ intake and HS increased expression of cytochrome P450 and detoxification pathways, respectively. Genes associated with immune response increased with long-term E+ at TN, but decreased with E+ diet at HS. Similarly, genes coding for chaperone and DNA repair decreased with long-term E+ at TN, but increased with E+ and HS. Recovery observed in E+ rats at TN could be attributed to increased gene expression for detoxification and immune response, whereas decreased antioxidant and immune response associated genes could contribute to distress associated with E+ at HS. Fescue toxicosis results from intake of toxins in fescue containing an endophytic fungus, Neotyphodium coenophialum. Time-related changes in rats associated with intake of an endophyte-infected fescue diet (E+) were evaluated under thermoneutral (TN), and both short- and long-term heat stress (HS) conditions. Short-term E+ intake decreased feed intake and growth rate under both conditions, whereas rats exhibited signs of adaptation during long-term exposure with better recovery occurring under TN conditions. Rats fed an E+ diet did not change core temperature during TN, but under HS conditions they exhibited a short-term increase in core temperature above control level. However, there was adaptive return of this temperature to TN level with long-term exposure. Short-term E+ intake at TN decreased serum glucose, urea nitrogen, alkaline phosphatase, and cholesterol; whereas long-term E+ intake under these conditions resulted in complete adaptation. In contrast, short-term E+ intake at HS did not affect serum biochemistry, while long-term intake decreased all the above mentioned serum parameters. Serum prolactin level was decreased during both short- or long-term TN and HS conditions. The E+ diet decreased hepatic antioxidant gene expression, with even greater reduction as a result of HS. Long-term E+ intake and HS increased expression of cytochrome P450 and detoxification pathways, respectively. Genes associated with immune response increased with long-term E+ at TN, but decreased with E+ diet at HS. Similarly, genes coding for chaperone and DNA repair decreased with long-term E+ at TN, but increased with E+ and HS. Recovery observed in E+ rats at TN could be attributed to increased gene expression for detoxification and immune response, whereas decreased antioxidant and immune response associated genes could contribute to distress associated with E+ at HS.
Author: Craig A. Roberts Publisher: John Wiley & Sons ISBN: 0891186379 Category : Technology & Engineering Languages : en Pages : 32
Book Description
Fescue toxicosis continues to be one of the most devastating problems in forage–livestock agriculture. Because there is presently no cure, using the most up-to-date management and prevention approaches are crucial. The 2nd edition of this important guide presents an easy-to-understand description of this complex problem, along with recommendations that are practical for real farm use.
Author: Jenny Katherine Bryant
Author: Jenny Katherine Bryant
Author: Sachin Bhusari
Author: Brandon Jermaine McClenton
Author: Raja Sekhar Settivari
Author: Henry A. Fribourg
Author: Craig Arthur Roberts
Author: Craig A. Roberts
Author: Edwin Benjamin Rajo Gomez
Author: Carla Ann Maness
Author: Randall Keith Dew