Increased melanomacrophage centres in the liver of reproductively dysfunctional female greater amberjack Seriola dumerili (Risso, 1810)

Abstract

The greater amberjack Seriola dumerili is a new aquaculture fish that may display reproductive dysfunctions. During extensive follicular atresia, which is a common reproductive dysfunction in females during vitellogenesis, part of the reabsorbed yolk returns to the liver to be metabolized and recycled. Melanomacrophage centres (MMCs) are aggregates of macrophage‐like cells that play a role in the destruction, detoxification and recycling of endogenous and exogenous materials, and have been associated with systemic stress. Wild and captive‐reared greater amberjack were sampled in the Mediterranean Sea during two different phases of the reproductive cycle. The liver of reproductively dysfunctional captive‐reared females sampled during the spawning season showed a high density of both MMCs and apoptotic cells. A weak liver anti‐cytochrome P450 monooxygenase 1A immunoreactivity was observed, suggesting that the examined fish were not exposed to environmental pollutants. We propose that the observed increase in MMCs and apoptosis in captive‐reared fish was related to the hepatic overload associated to the metabolism of yolk proteins reabsorbed during extensive follicular atresia. Since follicular atresia is a frequent physiological and pathological event in teleosts, we suggest that the reproductive state should be always assessed when MMCs are used as markers of exposure to stress or pollutants.

Stages of Granulomatous Response Against Histozoic Metazoan Parasites in Mullets (Osteichthyes: Mugilidae)

“…In the present study, the presence of aggregates of macrophages associated with the granuloma showed a variable presence not statistically correlated with granuloma developmental stages. This result suggests that their presence could be perhaps influenced by other factors, such as age and fish species, as reported by other authors on studies on exposure to pollutants, diet, environmental stress, and fish aging [99,100].…”

An autofluorescence‐based survey of late follicular atresia in ovaries of a teleost fish (Thunnus thynnus)

“…As in anchovy (Hunter & Macewicz, 1985), γ atretic follicles are not clearly distinguished in histological samples of bluefin tuna, because thecal cells are not observed around the atretic follicles after the β stage; therefore, the authors refer to atretic bodies (γ plus δ atresia) as LAF. LAF resemble the melanomacrophage centres containing lipofuscin described by Passantino et al (2020) in the liver of captive-reared Seriola dumerili.…”

“…Although atresia may occur at any stage throughout the oocyte development in teleosts, atretic follicles are more prevalent during secondary growth, because vitellogenic follicles contain a greater amount of reusable energy than earlier oogenetic stages (Domínguez-Castanedo et al, 2019). Atresia is enhanced in stressful situations, such as panic (Corriero et al, 2011), starvation (Corriero et al, 2011;Hunter & Macewicz, 1985), exposure to contaminants (Johnson et al, 1999;Migliaccio et al, 2018) or captivity (Corriero et al, 2004(Corriero et al, , 2007(Corriero et al, , 2011Passantino et al, 2020).…”

Atresia of ovarian follicles in fishes, and implications and uses in aquaculture and fisheries

“…As described above, oocyte atresia involves the fragmentation of the oocyte envelope to allow follicular cells to enter the oocyte and act as macrophages (Corriero et al., 2004 ; Domínguez‐Castanedo et al., 2019 ; Linares‐Casenave et al., 2002 ; Passantino et al., 2020 ; Santos et al, 2008 ). The loss of integrity of the oocyte results in the spreading of its components—including lysosomal enzymes—outside the follicle and invasion of neighbouring structures (Figure 2c ), an event that can lead to degradation of neighbouring structures, including unyolked and yolked follicles.…”