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ARS Home » Research » Publications at this Location » Publication #107031
Title: EFFECT OF EIMERIA ACERVULINA INFECTIONS ON PLASMA L-ARGININE

Author
item Allen, Patricia
item Fetterer, Raymond

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/1/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: We have examined the dependence of plasma levels of L-arginine (ARG), an essential amino acid for chickens, and the substrate for nitric oxide (NO) synthase, on infective dose of Eimeria acervulina, and the infection- associated changes in weight gain, plasma carotenoids and, plasma nitrite+nitrate (stable metabolites of NO). Chickens were infected with a range of doses of E. acervulina, and the effects of infections measured at 6 d postinoculation (PI). Plasma arginine was significantly correlated with plasma carotenoids (P > 0.0187), but not dose or gain, whereas plasma nitrite+nitrate was positively correlated (P > 0.0043) with dose and negatively correlated (P > 0.0158) with weight gain. Regression analysis again showed that the variation in plasma ARG with dose was most closely related to variation of plasma carotenoids. Since plasma carotenoid levels are a sensitive indicator for nutrient malabsorption, the results suggest that the reduction in plasma ARG levels during coccidiosis infections is primarily influenced by malabsorption that results from the infection- associated disruption of the intestinal mucosa. Importantly, malabsorption of ARG does not appear to hinder the inflammatory increase in plasma nitrite+nitrate. It is speculated that the close correlation of nitrite+nitrate levels with dose and gain indicates that inflammatory factors released during the immune response to infection may act systemically to cause weight gain depression, and that the immune response to E. acervulina infection may contribute substantially to the observed weight gain depression.

Technical Abstract: We have examined the dependence of plasma levels of L-arginine (ARG), an essential amino acid for chickens, and the substrate for nitric oxide (NO) synthesis by an induced enzyme (iNOS), on infective dose of Eimeria acervulina, and the infection-associated changes in weight gain, plasma carotenoids and, plasma nitrite+nitrate. Chickens were infected with a range of doses of E. acervulina. At 6 d postinoculation (PI), weight gains were significantly reduced by infections with 500,000, and 1,000,000 oocysts per chick (OPC). Gross lesion scores of chickens infected with 50,000 through 1,000,000 OPC were significantly greater than scores from chicks infected with 1,000 OPC. Plasma levels of ARG were significantly decreased by infection with 50,000 through 1,000,000 OPC, and plasma carotenoids were significantly decreased by all infection doses, whereas nitrite+nitrate levels were significantly increased by infection with 5,000 0through 1,000,000 OPC. Plasma arginine was significantly correlated with plasma carotenoids (P > 0.0187), but not dose or gain, whereas plasma nitrite+nitrate was positively correlated (P > 0.0043) with dose and negatively correlated (P > 0.0158) with weight gain. Regression analysis showed the strongest relationship between plasma ARG and carotenoids, suggesting that in this infection model, reduction in plasma ARG is most likely associated with nutrient malabsorption that accompanies infection, and is likely not significantly impacted by synthesis of NO that is associated with the immune response. Additionally, malabsorption of ARG apparently does not hinder significant increase in NO synthesis.