Influences of immunostimulants on phagocytes in cultured fish: a mini review

Abstract

Lower vertebrates like fish mostly depend on innate immunity as the first line of defence against invading pathogens. One of the defence mechanisms in innate immunity for fish is the use of phagocytic cells such as monocytes, macrophages, neutrophils, mast cells and dendritic cells in fighting pathogens. These cellular cells employ a variety of mechanisms in protecting fish including but not limited to; the use of pattern recognition receptors and antigen presenting cells to detect the presence of pathogens in host, neutralising them using measures including; inflammation, production of lysosomal enzymes released into the phagosome to neutralising pathogens and prevention of systemic autoimmunity by apoptosis. Some phagocytic cells play the extra role of serving as a bridge between innate and adaptive immunity in fish. Recent accumulating data showed that phagocyte cell activity in fish could be enhanced by a natural or chemical substance (immunostimulants) that stimulates the immune system in fish principally meant to enhance the immune response mechanisms. In this review, the main focus is on elucidating the distinct phagocytic mechanisms played by monocytes, macrophages, neutrophils, mast cells and dendritic cells as principal phagocytes in immune defence and how their activities are influenced by immunostimulants in cultured fish.

Trial for use nanoselenium particle with different dietary regime in Oreochromis niloticus and Mugil cephalus polyculture ponds: Growth efficiency, haematological, antioxidant, immunity and transcriptional analysis

“…Abarike et al. (2019) reported that Nano‐Se upregulates the pro‐inflammatory cytokines, which help our finding in Figures 1 and 2 that showed the marked upregulation of IL1B and IL8 in O. niloticus and M. cephalus fish that previously treated with Nano‐Se particle. IL‐1β is a pro‐inflammatory cytokine that stimulates the lymphocytes and macrophages against disease (Low et al., 2003).…”

Dietary essential oil extract from sweet orange (Citrus sinensis) and bitter lemon (Citrus limon) peels improved Nile tilapia performance and health status

“…Unlike, the expression of SOD was not affected by dietary supplementation of limonene; however, catalase was upregulated (Aanyu et al., 2018). The roles of OEO and/or LEO seems to have immunomodulatory effect and their dietary administration mainly upregulates pro‐inflammatory cytokines (Abarike et al., 2019). A similar result was obtained by (Abdel‐Latif et al., 2020) who found that dietary supplementation of oregano essential oil (15 g/kg) upregulated the relative expression of hepatic interleukin‐1beta ( IL‐1β ) and interleukin‐10 ( IL‐10 ) genes in common carp.…”

The effects of four plant extracts on growth, sex reversal, immunological and haemato‐biochemical parameters in Nile tilapia,Oreochmomis niloticus(Linnaeus, 1758)

“…Differential leucocyte counts in the present study were characterized by predominance of lymphocytes in all groups except EB, which showed predominance of monocytes. Monocytes are mostly short lived, undergo daily spontaneous apoptosis and often differentiate into other cells (Abarike et al., 2019), and hence, fish in general shows low monocyte percentage. Total WBC and monocyte percentage in control fish in the present study were similar to an earlier observation (Ighwela et al., 2012).…”

“…The present results are in conformity with several earlier reports where dietary administration of different plant extracts has significantly increased total RBCs, haemoglobin and haematocrit levels, total WBCs and monocytes in fish (Reverter et al., 2014). Fish treated with immunostimulants usually show enhanced phagocytic cell activities (Abarike et al., 2019). However, some earlier studies have reported lower haematological indices compared to control after treatment with herbal plant extracts (Gabriel, 2019).…”