Submitted to: Journal of Toxicology and Environmental Health
Publication Type: Peer reviewed journal
Publication Acceptance Date: 9/29/2001
Publication Date: 12/1/2002
Citation: JOHNSON, D., SMITS, J.E., JARONSKI, S., WEAVER, D.K. ASSESSMENT OF HEALTH AND GROWTH OF RING-NECKED PHEASANTS FOLLOWING CONSUMP-TION OF INFECTED INSECTS OR CONIDIA OF ENTOMOPATHOGENIC FUNGI, METARHIZIUM ANISOPLIAE VAR ACRIDUM & BEAUVERIA BASSIANA, FROM MADAGASCAR & N. AMERICA. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. 2002. V. 65. No. 24. P. 2145-2162. Interpretive Summary: This study reports the absence of adverse toxicological or pathogenic effects of two insect pathogenic fungi, Beauveria bassiana and Metarhizium anisopliae var. acridum, in pheasants. Young birds were fed either fungus- contaminated food or fungus- killed grasshoppers and examined after 21 days from the initial exposure. Weight gain and tarsal length were unaffected; histopathological changes were absent or minor.
Technical Abstract: Isolates of Beauveria bassiana and Metarhizium anisopliae var acridum from Madagascar, are being developed for control of grasshoppers and locusts. Probable effects of these entomopathogens on nontarget spec- ies must be determined before operational use. Birds may become ex- posed to these fungi either directly, by consuming spores deposited on their food items, or may be secondarily exposed by consuming grasshoppers or locusts that have died from infection by these bio- control agents. This paper presents the results of per os challenge from fungus-infected food items. Male and female ring-necked phea- sants (Phasianus colchicus) were exposed at 4 and 9 days of age, to challenge treatments or two control treatments. Pheasants were weigh- ed at 9, 17 and 25 days of age, tarsal length was measured at 25 days of age, and they were observed daily for signs of adverse effects of the experimental treatments. At the time of euthanasia (25 days of age), 2 or 3 randomly selected birds from each of the groups exposed to in- fected grasshoppers, plus the two control groups, underwent complete necro- psies & histopathological examination of 16 tissues from each bird.Results show that in both sexes, weight gain, at both 17 & 25 days was not signifi- cantly different between challenge groups & control groups. Tarsal length at 25 days of age, an indication of structural growth,was also not markedly different among challenged and control groups. Histopathological changes were generally undetectable, mild or moderate, and not consistently associ- ated with any treatment. Based upon these findings, there is little indica- tion that birds are susceptible to acute detrimental health effects from direct or secondary exposure to the two entomopathogenic fungi studied.