Browsing by Subject "Ascophyllum nodosum"
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Item Influence of Ascophyllum nodosum on selenium and antioxidants in beef cattle(Texas Tech University, 2001-12) Cradduck, Will C.Tasco, a proprietary product derived from a brown kelp {Ascophyllum nodosum). has altered antioxidants in plants and animals. Selenium (Se) is a component of glutathione peroxidase, a cellular antioxidant, which is closely related to vitamin E in activity. Antioxidants have been implicated in the improved immune fiinction of steers and shelf life of the meat from steers that grazed pastures treated with Tasco. Therefore, experiments were conducted to determine the effects of Tasco products on Se concentrations in forage and cattle. In Experiment 1. Tasco-Forage (a water-soluble extract) was applied (3.5 kg/ha in April and July) to endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon, and Hanlin) -infected and endophyte-free tall fescue {Festuca arundinacea) grazed by Angus steers in Virginia during 1995 (initial mean BW 245 kg; SD = 20), 1996 (initial mean BW 234 kg; SD = 9), and 1997 (initial mean BW 265 kg; SD = 5). Tasco tended (P = 0.11) to decrease Se in endophyte-infected tall fescue and increased (P < 0.05) Se in endophyte-free tall fescue (interaction; P < 0.05) when averaged over years and dates. By the end of the grazing season, steers that grazed Tasco-treated fescue had higher (P < 0.05) Se in serum (1996) and whole-blood (1997) than steers that grazed non-treated fescue, regardless of the endophyte. Endophyte-infected tall fescue decreased (P < 0.05) serum Se (1996) and whole-blood Se (1997) compared with non-infected fescue. At the end of grazing, steers were finished on a feedlot in Texas. No differences in serum Se were observed following feedlot fmishing. In Experiment 2, Tasco-14 (a meal from dried, ground, intact A. nodosum) was fed (0, 1.5, or 3.0% of diet, DMB) to crossbred steers (Trial 1 initial mean BW = 332 kg, SD = 37; Trial 2 initial mean BW = 340 kg, SD = 18) during a 127-d eedlot finishing period. Steers were fed a diet based on steam-flaked com {Zea mays L.: Trial 1) or steam-flaked milo {Sorghum bicolor; Trial 2). No differences in serum Se were observed by harvest, but liver Se decreased linearly (P < 0.05) at harvest as a result of Tasco treatment in Trial 2. In Experiment 3, Tasco-EX fed to steers for the final 2-wk in the feedlot, at 0, 1, and 2% of the dietary DM had no effect on serum Se but linearly (P < 0.05) decreased serum vitamin A. Serum vitamin E of steers fed 1% Tasco did not increase as much as controls (P < 0.05) over the 2-wk period. Vitamin A, E, and Se were not affected in liver. In Experiment 4, sale bam heifers were supplemented (90 g d"' target consumption) with Tasco-EX in the drinking water for a 2-wk period. No effect on serum Se was observed at the end of the 2-wk supplementation period as a resuh of Tasco treatment. In Experiment 5, Tasco-14 was fed (0.18 kg hd'' d'') to Angus-crossbred (initial mean BW = 238 kg, SD=18) steers for 2-wk before transport to the feedlot, and for 2-wk after arrival. No effect of Tasco treatment on semm Se was observed immediately before or immediately after transport. No effect on whole-blood Se was observed 2-wk after transport. Tasco increased blood Se in grazing steers, but changes in blood Se only partially reflected differences in forage Se. Effects of Tasco on forage Se concentration depended on the presence of the endophyte. Application of Tasco to forage in Se deficient regions might improve Se status of grazing livestock. Presence of the endophyte decreased Se in the animal but not in the forage. Direct feeding of Tasco to steers did not aher serum Se, but decreased liver Se with long-term feeding and depressed serum vitamin A and E with short-term feeding. Treatment of beef heifers with Tasco in the drinking water did not aher serum Se. Tasco increased Se concentrations in endophyte-free tall fescue forage from Se deficient areas, but not endophyte-infected tall fescue. Other mechanisms working through the forage that are not totally understood, as well as ahered Se concentration of the forage, might provide an altemative to direct Se supplementation in deficient areas by increasing the Se status of cattle grazing both endophyte-infected and endophyte-free tall fescue.Item The effect of seaweed (Ascophyllum nodosum) extract on antioxidant activities and drought tolerance of tall fescue (Festuca arundinacea schreb.)(Texas Tech University, 1998-08) Ayad, Jamal YousefPlants have developed enzymatic and nonenzymatic antioxidant mechanisms to prevent oxidation of cellular compartments. Enhancing these mechanisms might help plants cope with encountered stresses. Greenhouse and field studies were conducted to examine the influence of seaweed(Ascophyllum nodosum) extract on antioxidant enzymes activities, forage growth, and persistence of tall fescue (Festuca arundinacea Schreb.). Furthermore, effects of soil moisture, plant genotype, and infection with the endophyte Neotyphodium coenophialum ([Morgan-Jones and Gams] Glenn, Bacon and Hanlin) were investigated. In a greenhouse experiment, seaweed extract was applied to 'Martin' tall fescue at 0, 2, 4, 6, 8, and 10 kg ha^-1 in a randomized block design with four replicates. Seaweed extract linearly increased (P <0.05) glutathione reductase activity. Superoxide dismutase and ascorbate peroxidase were also increased but responses differed by time and treatment rates. In a second greenhouse experiment, seaweed extract was applied at 4 kg ha^-1 to endophyte-infected and non-infected 'Georgia Jessup' and 'KY-3r tall fescue grown with 50-100% and 30-100% field capacity soil moisture in a completely randomized design with four replications. Glutathione reductase activity increased (P < 0.05) in both genotypes in response to seaweed extract and moisture stress and tended to increase (P < 0.07) in response to the endophyte. Seaweed extract increased (P < 0.05) superoxide dismutase activity in both genotypes under water stress. Endophyte infected and non-infected KY-31 tall fescue were grown in a 2-yr field experiment, to investigate effects of 4 kg seaweed ha^-1 and three levels of irrigation to replace 0, 50,100% of potential evapotranspiration in a randomized block design with four replications. Superoxide dismutase, glutathione reductase, and ascorbate peroxidase activities were increased (P < 0.05) in response to seaweed extract, presence of the endophyte, and increased linearly (P < 0.05) in response to increased moisture stress. Plant growth and yield did not appear to be affected by seaweed extract at the applied rates. Results indicated that seaweed extract increased tall fescue antioxidant enzyme activities and may provide a tool for manipulating the antioxidant system in plants for increased protection against active oxygen species.Item The effects of Ascophyllum nodosom on immune function, performance, and carcass characteristics of sheep and cattle(Texas Tech University, 2000-05) Gravett, Richard BrentTwo experiments were conducted to evaluate the efficiency of Ascophyllum nodosum (Tasco) fed to sheep or cattle. In experiment 1, 54 wether lambs were fed Tasco-14 (meal) or Tasco- EX (extract) at dietary levels of 0.0%, 0.25%, 0.50%, 1.0% and 2.0%, to determine performance characteristics, carcass characteristics and immune function traits. There were no differences among all treatments for performance characteristics (P>.05), carcass traits, and hnmune response (P>.05). Immune response was also not different (P>.05) among the extract, meal and control diets.