Papers by Randolph Richards
Diseases in Asian aquaculture IV: Proceedings of the Fourth Symposium on Diseases in Asian Aquaculture, 22-26 November 1999, Cebu City, Philippines, 2002
Journal of Medical Microbiology, 2018
Journal of Fish Diseases, 1994
Journal of Fish Diseases, 2002
The efficacy of emamectin benzoate as an oral treatment of sea lice, Lepeophtheirus salmonis (KrÒ... more The efficacy of emamectin benzoate as an oral treatment of sea lice, Lepeophtheirus salmonis (KrÒyer), infestations in Atlantic salmon, Salmo salar L., was evaluated in a dose titration study and two dose confirmation studies. Replicated groups of salmon with induced infestations of sea lice were given emamectin benzoate on pelleted feed at doses of 0, 25, 50 and 100 μg kg−1 biomass day−1 for seven consecutive days. Sea lice were counted at 7, 14 and 21 days from the start of treatment, and comparisons made with control fish given the same diet without emamectin benzoate. Total numbers of sea lice were significantly reduced at all doses in all three studies when compared to control fish. There was no significant difference between doses of 50 and 100 μg kg−1, but the 50 μg kg−1 dose resulted in significantly fewer lice than the 25 μg kg−1 dose. Emamectin benzoate was highly effective in reducing numbers of preadult and adult lice and prevented the maturation of chalimus to motile st...
Journal of Fish Diseases, 1992
Journal of Fish Diseases, 1991
Journal of Fish Diseases, 1986
Journal of Fish Diseases, 1993
Journal of Fish Diseases, 1984
A detailed review of proliferative kidney disease (PKD) in salmonids is presented. The introducti... more A detailed review of proliferative kidney disease (PKD) in salmonids is presented. The introduction places the disease in a historical context. The various aspects of the disease are described from the existing literature, together with latest findings from current research. Particular emphasis is given to epidemiology, aetiology and pathology.
Journal of Fish Diseases, 1978
Journal of Fish Diseases, 1978
Journal of Fish Diseases, 1996
The gross, histological and scanning electron microscopic appearance of dorsal fin rot in farmed ... more The gross, histological and scanning electron microscopic appearance of dorsal fin rot in farmed Atlantic salmon parr, Salmo salar L. is described. The lesions were grouped into seven categories: (1) peripheral erosion and ray splitting; (2) peripheral erosion with some nodularity; (3) severe nodularity with differing degrees of tissue loss; (4) extensive to total loss of the dorsal fin; (5) smooth thickening of the dorsal fin; (6) haemorrhagic dorsal fin lesions; and (7) healed dorsal fin rot lesions. The main sign of injury was clefts extending through the epithelium. These injuries were consistent with bites from other parr. During healing from such wounds, damaged cells sloughed from the surface, and there was swelling and hyperplasia in the remaining cells. The majority of the thickening in the fins was the result of epithelial hyperplasia with a variable cellular inflammatory response. The distal epithelium of fins with severe fin rot (i.e. nodular and eroded) was rough, irreg...
Journal of Fish Biology, 1988
Journal of Fish Biology, 1983
The kidneys of similar sized rainbow trout from freshwater and seawater environments were examine... more The kidneys of similar sized rainbow trout from freshwater and seawater environments were examined and several parameters of renal corpuscular morphology were measured, The glomeruli of the seawater trout were significantly smaller and contained significantly fewer red blood cells than those of the freshwater fish. There was also some evidence of a decreased number of renal corpuscles per unit area, and an increased proportion with no apparent capsular space in the seawater trout.
Journal of Aquatic Animal Health, 1997
Abstract Tissues from rainbow trout Oncorhynchus mykiss that had been exposed to proliferative ki... more Abstract Tissues from rainbow trout Oncorhynchus mykiss that had been exposed to proliferative kidney disease (PKD) infective waters were sampled from May through to August. These tissues were examined via immunohistochemistry with four monoclonal antibodies (MAbs) previously raised to the causative agent of PKD, a myxosporean termed PKX. The results showed the MAbs were specific for different phases in the parasite's life cycle. Immunogold electron microscopy revealed that three of the MAbs appeared to be specific for vacuoles within the extrasporogonic parasites, and the fourth MAb was specific for secondary cells within the extrasporogonic parasite and for sporogonic stages. Intensification of the staining properties of the parasite through its maturation in the kidney, as demonstrated by immunohistochemistry, indicates that the extrasporogonic parasite may undergo autophagy during the release of maturing secondary cells.
Journal of Aquatic Animal Health, 1996
ABSTRACT
Fish & Shellfish Immunology, 2013
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Papers by Randolph Richards