Alteration of rodlet cells in chub caused by the herbicide Stam Ò M-4 (Propanil) B. S. D EZFULI *†, L. G IARI *, E. S IMONI *, D. P ALAZZI ‡ AND M. MANERA § *Department of Biology, University of Ferrara, Via Borsari 46, 44100 Ferrara, Italy, ‡Environmental Protection Agency, C. so Giovecca 169, 44100 Ferrara, Italy and §Department of Alimentary Sciences, University of Teramo, P.zza A. Moro 45, 64100 Teramo, Italy (Received 18 March 2002, Accepted 23 May 2003) Handling stress and exposure to the herbicide Stam Ò M-4 (Propanil) were associated with an exponential depletion of the rodlet cells (RC) in the bulbus arteriosus of chub Leuciscus cephalus. Structural changes of the RC in herbicide-exposed fish were encountered, including the occurrence of myeloid bodies in the cytoplasm of the RC of the intestine, various degrees of rodlet degeneration and high vacuolization in the cytoplasm of RC in almost all examined organs of exposed chub. # 2003 The Fisheries Society of the British Isles Key words: alteration; chub; herbicide; Propanil; rodlet cells. INTRODUCTION Herbicides frequently replace mechanical methods of weed control in countries practicing intensive and highly mechanized agriculture. Propanil (3 0 ,4 0 -dichloro- propionanilide) is a post emergence amide herbicide used to control grass and weeds in rice (Smith, 1965). Propanil toxicity and its metabolism has been reported in mammals (Chow & Murphy, 1975). There are some records of acute lethality of Propanil in exposed fishes (Chaiyarach et al., 1975; Davey et al., 1976; McCrokle et al., 1977). Limited data are available, however, for long-term exposures of fishes to Propanil and its metabolites and their accumulation in fish tissues (Call et al., 1983). In an investigation on the fathead minnow Pimephales promelas Rafinesque exposed to Propanil, it appeared that this herbicide was very toxic to fishes (Call et al., 1983). According to Call et al. (1983), ‘low levels of technical grade Propanil adversely affect fish hatchability, the normal development of and survival of newly hatched fry, and the growth and survival of juvenile fish.’ In a recent study of effects of dexamethasone (a glucocorticoid) on presence and structure of rodlet cells (RC) in goldfish Carassius auratus (L.) there was no significant †Author to whom correspondence should be addressed. Tel.: þ39 532 291334; fax: þ39 532 249761; email: dzb@unife.it Journal of Fish Biology (2003) 63, 232–239 doi:10.1046/j.1095-8649.2003.00151.x, available online at http://www.blackwell-synergy.com 232 # 2003 The Fisheries Society of the British Isles