Progress 10/01/99 to 09/30/04
Outputs
The relationship between dietary antioxidants and ascorbic acid (AsA) synthesis was examined in meat type chickens and mature male Japanese quail fed diets low or deficient in vitamin E. Iron overload depressed AsA synthesis in chicks fed a practical diet without supplemental Se and vitamin E. Under these conditions neither hepatic dehydroascorbic acid reductase nor N-acetyl-B-glucosaminidase was affected. A similar experiment Japanese quail were fed a purified diet for 10 weeks to ascertain whether vitamin E deficiency up-regulates L-gulonolactone oxidase (GLO) activity and supplemental vitamin E down-regulates GLO activity. Ascorbic acid synthesis was depressed in birds fed a vitamin E deficient diet and this was further aggrevated by AsA supplementation. Ascorbic acid synthesis increased with the addition of 10 IU vitamin E but down-regulation was not observed as vitamin E was increased to 100 IU/kg. Based on the results there was no evidence of up-regulation or
down-regulation of GLO in mature male Japanese quail fed an antioxidant deficient diet. The results suggest that meat type chickens with a short life cycle and male Japanese quail (with little out go of vitamin E in eggs) are relatively resistant to antioxidant stress induced by vitamin E deficiency. Further research is required to examine the responses in poultry exposed to an inflammatory condition.
Impacts
Short-term vitamin E deficiency in meat type chickens and male Japanese quail did not induce oxidative stress that required supplemental vitamin C in the diet.
Publications
- Hooper, C.L., 1999. Factors influencing biosynthesis of ascorbic acid in the domestic fowl. M.S. Thesis, Graduate Nutrition Program, Clemson University, Clemson, SC 29634-0311, U.S.A.
- Ong, C.C., 1999. Antioxidant capacity of selected tissues in chickens during development and growth. M.S. Thesis, Graduate Nutrition Program, Clemson University, Clemson, SC 29634-0311, U.S.A.
- Maurice, D.V., S.F. Lightsey, and J.E. Toler, 2004b. Ascorbic acid biosynthesis in hens producing strong and weak eggshells. Brit. Poultry Sci. 45:404-408.
- Maurice, D.V., S.F. Lightsey, and J.E. Toler, 2004. Factors affecting ascorbic acid biosynthesisin chickens. IV. Effect of cadmium and vanadium on L-gulonolactone oxidase activity and tissue ascorbic acid concentration. J. Anim. Physiol. Anim. Nutr. 88: 427-433.
- Watts, J.C., 2004. Effects of dietary iron overload on ascorbic acid metabolism and oxidative stress. Ph.D. Dissertation, Graduate Nutrition Program, Clemson University, Clemson, SC 29634-0311, U.S.A.
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Progress 01/01/03 to 12/31/03
Outputs
Poultry, renal ascorbic acid (AsA) synthesizers, are often given supplemental ascorbic acid when exposed to stressors. There is no evidence that stress impairs biosynthesis and hence the rationale for nutritional intervention in species that synthesize ascorbic acid is questionable. Two experiments were conducted to evaluate the effect of stressors on AsA synthesis. Stress responses in six week old broiler chickens were elicited by continuous ACTH release, from subcutaneously implanted mini-osmotic pumps,at 8 IU/kg BW/day for 7 days. In stressed chickens body weight (500 g loss)and bursal weight were reduced,plasma corticosterone elevated and activity of L-gulonolactone oxidase (GLO) was depressed. The results clearly indicated that ACTH at the level used reduced AsA synthesis. In experiment 2 hyperthyroidism was induced by feeding broiler chickens triiodothyronine at 1.5 mg/kg for 6 weeks. Hyperthyroidism reduced GLO activity, increased hepatic dehydroascorbic acid
reductase, and increased the incidence of ascites. Supplemental AsA also down-regulated GLO activity but partially alleviated the ascites induced by hyperthyroidism. The results of the two experiments showed that biosynthesis of AsA in chickens is reduced and hepatic recycling increased during extreme stress and synthesis down-regulated by dietary AsA. Even though ascites was associated with reduced AsA synthesis in a hyperthyroid state, intervention down-regulated synthesis but alleviated ascites syndrome. This suggests that high circulating level of AsA induced by dietary AsA may be beneficial under some conditions even though innate synthesis is down-regulated.
Impacts
Continuous infusion of ACTH and hyperthyroidism in chickens inhibits biosynthesis of ascorbic acid (AsA). Dietary AsA intervention is beneficial in reducing mortality from ascites in broiler chickens.
Publications
- Laverty,G.and Maurice,D.2003. Ascorbic acid-stimulated transport current in avian proximal tubule monolayers. Proceedings Experimental Biology 2003.
- Burnham,M.R.,Peebles,E.D.,Branton,S.L.,Maurice,D.V.and Gerard,P.D.2003. Effects of F-strain Mycoplasma gallisepticum at twelve weeks of age on egg yolk composition in commercial egg laying hens. Poultry Sci. 82:577-584.
- Hughes,M.and Maurice,D.V.2003.Effect of dietary L-ascorbic acid or physiological stress on L-gulonolactone oxidase activity and tissue ascorbic acid concentration in domestic chickens. Page 11 in 14th Annual Research Colloquium SC Governor's School for Science and Mathematics
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Progress 01/01/02 to 12/31/02
Outputs
Chickens synthesize ascorbic acid (AsA)and the inconsistent responses to supplementation may be due to dietary factors that alter synthesis or tissue turnover of AsA. Fluoride may enter the food chain of via industrial contamination, feed ingredients, and drinking water. The effect of 300 mg/kg fluoride in the diet was tested in the diet of meat type chickens. The experimental diet was fed from day-old to three weeks of age and the responses measured were L-gulonolactone oxidase activity, tissue AsA concentration. Growth and feed efficiency were not affected by fluoride in the diet. Dietary fluoride neither inhibited nor enhanced L-gulonolactone oxidase activity nor did it increase or decrease AsA content in plasma, liver, kidney, adrenal gland, and muscle (pectoralis major). Tissue AsA in ascending order was adrenal > liver > kidney > muscle > plasma. The results are consistent with that reported for the rat. Based on the results of this study it is highly improbable
that fluoride as a contaminant in feed phosphorus affects AsA biosynthesis through its affect on the activity of L-gulonolactone oxidase or turnover in different tissues.
Impacts
Feed grade phosphates must contain no more than one part fluorine to 100 parts phosphorus. A feed grade phosphate with 20% phosphorus and used at 2% in a poultry diet will contribute 40 mg fluorine/kg. This amount is negligible compared with the dose used in this experiment that was 7.5 times the upper limit of fluorine in feed phosphates. Hence, Fluorine from feed phosphates available in the U.S.A. does not impair ascorbic acid biosynthesis in chickens.
Publications
- Hooper,C.L.,Maurice,D.V.,Lightsey,S.F. and Toler, J.E. 2002. Factors affecting ascorbic acid (AsA) biosynthesis in chickens. II. Effect of dietary AsA and strain of chicken. J.Anim.Physiol.Anim.Nutr.86:326-332.
- Maurice,D.V.,Lightsey,S.F.,Abudabos,A. and Toler,J.E. 2002. Factors affecting ascorbic acid biosynthesis in chickens. III. Effect of dietary fluoride on L-gulonolactone oxidase activity and tissue ascorbic acid concentration. J.Anim.Physiol.Anim.Nutr. 86:383-388.
- Maurice,D.V.,Lightsey,S.F. and Toler,J.E. 2002. Effect of varied amounts of dietary ascorbic acid on concentration of plasma and hepatic ascorbate and L-gulonolactone oxidase activity. Proc.International Poultry Scientific Forum, Abstract No. 142 Southern Poultry Science Society, Georgia World Congress Center, Atlanta, GA
- Maurice,D.,Lauridsen,C.,Jorgensen,H. and Toler,J.E. 2002. Tissue ascorbic acid and L-gulonolactone oxidase activity in heat-stressed and ascorbic acid supplemented chickens. Proc.International Poultry Scientific Forum, Abstract No. 180 Southern Poultry Science Society, Georgia World Congress Center, Atlanta, GA
- Cosgrove,J.,Lightsey,S.F. and Maurice,D.V. 2002. Effects of dietary iron overload on ascorbic acid metabolism and oxidative stress in an avian model. Proc.Experimental Biology 2002, New Orleans, LA
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Progress 01/01/01 to 12/31/01
Outputs
A series of experiments were conducted to examine the effect of varying levels of dietary ascorbic acid (AsA), duration of feeding, and acute high environmental temperature (AHET) on AsA biosynthesis and metabolism. Broiler chickens fed 0, 250, 500 and 1000 mg/kg AsA were sampled at 1, 2, 4 and 12 weeks of age. A significant diet by time interaction was detected for tissue AsA and L-gulonolactone oxidase activity (GLO). All levels of AsA inhibited GLO activity and increased tissue AsA but the response differed with time. The results are consistent with the hypothesis that dietary ascorbic acid inhibits biosynthesis and the degree of inhibition is dose- and time-dependent. The results suggested that at low doses the response may be compounded by chronic high temperature as the experiment was conducted in summer. The effects of dietary ascorbic acid and high temperature was assessed by exposing chickens to AHET (three cycles of 30 min at 44 C and 40% RH and 30 min at 25
C and 40% RH)in a calorimeter. Chicks exposed to AHET exhibited normal adaptive responses and there was no mortality during or after exposure. Neither a diet x AHET interaction nor effect of AHET was detected for tissue AsA and GLO activity. The results confirmed that dietary AsA is an important regulator of GLO activity and showed that brief and limited episodes of AHET did not impair AsA biosynthesis in chickens.
Impacts
Supplemental ascorbic acid inhibits biosynthesis of the vitamin in chickens that are normally renal synthesizers. Further, biosynthesis is not affected by short-term acute heat stress. The results contraindicate routine fortification of poultry diets with ascorbic acid in anticipation of sudden short-term heat stress. There is a need to evaluate need for supplementation under conditions of chronic heat stress and /or handling and transport.
Publications
- Creel,L.H.,D.V.Maurice,S.F.Lightsey and L.W.Grimes,2001. Stability of dietary ascorbic acid and the effect of supplementation on reproductive performance of broiler breeder chickens. British Poultry Sci.42:96-102.
- Cosgrove,J.J.,D.V.Maurice and S.F.Lightsey,2001. The effect of supplemental ascorbic acid and iron on ascorbic acid metabolism in chickens. Proceedings International Poultry Scientific Forum, Georgia World Congress Center, Atlanta, GA p 7.
- Cosgrove,J.J.,D.V.Maurice and S.F.Lightsey, 2001. Effect of dietary iron overload on plasma total antioxidant capacity and hepatic lipid peroxides in chickens. Poultry Sci.80(Supplement 1):133
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Progress 01/01/00 to 12/31/00
Outputs
An experiment was conducted to determine the effect of high dietary iron on hepatic iron accumulation and ascorbic acid metabolism. Control broiler chicks were fed a practical diet containing 264 mg Fe/kg and test diets with 2000 and 3500 mg/kg Fe. Hepatic Fe increased as dietary Fe increased. Histological analysis showed that Fe infiltration was positively correlated to ingested Fe. Plasma ascorbic acid was decreased in birds fed excess iron and ascorbate biosynthesis, as measured by gulonolactone oxidase activity was increased. The results showed that excess Fe imposes oxidative stress that induces increased biosynthesis of ascorbate. An experiment was conducted with laying hens to determine whether changes in shell quality towards the end of lay is associated with reduced biosynthesis of ascorbate to test the hypothesis that weak eggshells are the result of decreased ascorbic acid synthesis. Hens producing stron and weak egg shells were samples from two strains of
layers and within each strain birds were pair matched for egg production and egg weight. Plasma ascorbate and ascorbic acid biosynthesis were not affected by strain or shell strength group. The results indicated that shell breakage that occurs inthe later phase of the egg production cycle is not due to reduced ascorbate biosynthesis.
Impacts
The chicken has no obligatory ascorbic acid requirement but diets are frequently supplemented at additional cost. The results clearly showed that innate biosynthesis is responsive to dietary variables and that shell strength problems in layers is not associated with ascorbic acid deficiency.
Publications
- Hooper,C.L.,D.V.Maurice,S.F.Lightsey and J.E.Toler, 2000. Factors affecting ascorbic acid biosynthesis. I. Adaptation of an assay and the effect of age, sex and food deprivation. J.Anim.Physiol.a.Anim.Nutr.84:48-56.
- Cosgrove,J. and D.V.Maurice,2000. Effect of dietary iron overload on ascorbic acid metabolism in an avian model. Proceedings Third Symposia Comparative Nutrition Society 3:29-33.
- Cosgrove,J. and D.V.Maurice,2000. Iron overload and ascorbic acid synthesis in chickens. Poultry Sci.79 (Supplement 1):94.
- Maurice,D.V. and S.F.Lightsey,2000. Ascorbic acid biosynthesis in hens producing strong (SS) and weak (WS)eggshells. Poultry Sci.79 (Supplement 1):126.
- Cosgrove,J. and D.V.Maurice,2000. Iron overload and ascorbic acid metabolism in chickens. Poultry Sci.79 (Supplement 1):14.
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