Moderate pathogenic effect of Ligophorus uruguayense (Monogenoidea, Ancyrocephalidae) in juvenile mullet Mugil liza (Actinopterygii, Mugilidae) from Brazil

Abstract

Monogenoidea pathogenic activity can elicit various histological responses in fish. Species of Ligophorus are specific parasites of mullets, and its relationship with host fish may result in a moderate pathogenic action. In order to ascertain this relationship, estuarine mullets (Mugil liza) were collected in an estuary, reared in laboratory, for three weeks, and forwarded for histological and parasitological analyses. Ligophorus uruguayense (Monogenoidea) infestation in the gills of the mullets was identified. The severe infestation by only one species of Monogenoidea may result from the specificity of these parasites to mullets. Mullets submitted to histological analysis exhibited respiratory epithelium detachment; mild, moderate and severe hyperplasia of the respiratory epithelium; atrophy; and telangiectasia of the gills. This is the first study reporting that mullets highly infested by Monogenoidea can show mild (100%) to severe (20%) gill changes with a distinct frequency of occurrence. Because of the high prevalence of mild alterations observed, it is possible to accept that L. uruguayense is moderately pathogenic to M. liza, even during high prevalence and intensity of infestation, as a result of its specificity.

Histopathological alterations caused by monogenean parasites the gills of tambaqui Colossoma macropomum (Serrasalmidae)

“…Monogeneans attach mainly to the gills of the hosts and can transfer between hosts at any stage of their lifecycle without a specific transmission stage. These ectoparasites can cause pathogenicity (Aragort et al, 2002;Kaur & Shrivastav, 2014;Pahor, Klosterhoff, Marchiori, & Pereira, 2017;Grano-Maldonado, Rodríguez-Santiago, García-Vargas, Nieves-Soto, & Soares, 2018;Hoai, 2020). The pathogenicity can vary among species and in depending on infection levels.…”

“…reported that the damaging effects of these parasites are noticed when changes occur within the host, such as physiological (e.g, cell proliferation, immunosuppression, altered growth and detrimental behavioral responses) or mechanical damages (e.g., fusion of gill lamellae, epithelial desquamation, hypertrophy, tissue replacement of gills). Hence, these ectoparasites can affect the health of fish and are one of the major factors that contribute to mortality and epizooties in farmed fish (Kaur & Shrivastav, 2014;Pahor et al, 2017;Grano-Maldonado et al, 2018).…”

“…The prevalence and abundance of A. spathulatus, M. boegeri and N. janauachensis showed variations in the gills of C. macropomum (Table 1), and the prevalence was higher when compared to that reported by Aragort et al (2002) for this host infected with A. spathulatus and L. brinkmanni. Studies have reported the potential damages caused by monogeneans in infected fish (Aragort et al, 2002;Campos, Moraes, & Moraes, 2011;Pahor et al, 2017). Monogeneans proliferate rapidly in rearing systems and attack using its haptor that has abrasive activity (Pahor et al, 2017;Hoai, 2020), which can harm production of fish farming due to respiratory damages and mortality.…”

“…Studies have reported the potential damages caused by monogeneans in infected fish (Aragort et al, 2002;Campos, Moraes, & Moraes, 2011;Pahor et al, 2017). Monogeneans proliferate rapidly in rearing systems and attack using its haptor that has abrasive activity (Pahor et al, 2017;Hoai, 2020), which can harm production of fish farming due to respiratory damages and mortality. Gill filaments in most fish are long and narrow projections lateral to the gill arch that taper at their distal end.…”

“…Nevertheless, the presence of this monogenean species was not observed in the present study. A high infestation of Ligophorus uruguayense Siquier & Ostrowski de Núñez, 2009 also caused severe damage in the gills of wild Mugil liza Valenciennes, 1836, such as low incidence of severe hyperplasia and necrosis of the respiratory epithelium of the hosts (Pahor et al, 2017). Moderate infestation of Gyrodactylus cichlidarum Paperna, 1968 caused a swelling of the apex of the primary and secondary lamellae with hyperplasia in the gills of Oreochromis niloticus Linnaeus 1756, with the presence of a large number of undifferentiated proliferating cells, hypertrophy and interlamellar necrosis, which lead to mortality (Grano-Maldonado et al, 2018).…”