Browsing by Author "Kelly, Scott"
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Item Effect of injected growth hormone on phagocytosis in silver sea bream (Sparus sarba) adapted to hyper- and hypo-osmotic salinities(1997) Narnaware, Yuwaraj; Kelly, Scott; Woo, NormanGrowth hormone (GH) is known to exert a myriad of functions throughout the vertebrates and in fish, its growth-stimulating and osmoregulatory e#ects are most prominent (Sakamoto et al., 1993; Chen et al., 1994). In mammals, GH is generally considered to be the principal hormone which exerts immunoregulatory properties and there is recent evidence for a similar e#ect of GH in fish (Sakai et al., 1996a,b,c). GH influences the immune processes from antibody formation to the appearance of di#erentiation markers on lymphocytes and augments the cytolytic activity of T cells, their proliferation and delayed type hyper-sensitivity (Blalock, 1989, 1994). These also include the enhancement of natural killer cell activity, mitogenic responses of lymphocytes and antibody production (Kelley, 1989).Item Effect of salinity and ration size on macrophage phagocytosis in juvenile black sea bream (Mylio macrocephalus)(2000) Narnaware, Yuwaraj; Kelly, Scott; Woo, Ying Shiu NormanThe effects of salinity adaptation and ration size on macrophage phagocytosis were assessed in black sea bream (Mylio macrocephalus) juveniles. Salinity had no effect on phagocytosis in fish that were fed a 10% ration size. Reducing ration size from 10 to 5% resulted in a significant reduction in splenic and pronephric macrophage phagocytosis of fish adapted to hyper-(33 p.p.t.) and hypo-osmotic (6 p.p.t.) salinities. The fish that were adapted to an iso-osmotic salinity (12 p.p.t.) and fed a 5% ration size were able to maintain macrophage phagocytic activity at levels comparable to those of fish that were fed a 10% ration size. It is proposed that the adaptation of sea bream to an iso-osmotic medium is beneficial in that it stimulates the immune response through activation of macrophage phagocytosis.Item Stimulation of macrophage phagocytosis and lymphocyte count by exogenous prolactin administration in silver sea bream (Sparus sarba) adapted to hyper- and hypo-osmotic salinities(1998) Narnaware, Yuwaraj; Kelly, Scott; Woo, NormanJuvenile silver sea bream (Sparus sarba) were adapted to hyper- (33 ppt) and hypo-osmotic (6 ppt) salinities for 3 weeks and injected daily with ovine prolactin (1 μg/g body weight i.p.) during the last 7 days of the adaptation period. Fish injected with prolactin exhibited significant increases in percent phagocytosis and phagocytic index of both pronephric and splenic macrophages regardless of salinity. Prolactin injection also resulted in elevated blood lymphocyte counts in both hyper- and hypo-osmotically adapted sea bream. The present results provide further evidence for the existence of a neuroendocrine–immune link in teleosts.