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Bactericidal Complement Activity and Concentrations of Immunoglobulin M, Transferrin, and Protein at Different Ages of Channel Catfish
Author(s) -
Ourth Donald D.,
Ratts Vicki D.,
Parker Nick C.
Publication year - 1991
Publication title -
journal of aquatic animal health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 52
eISSN - 1548-8667
pISSN - 0899-7659
DOI - 10.1577/1548-8667(1991)003<0274:bcaaco>2.3.co;2
Subject(s) - catfish , ictalurus , biology , globulin , antibody , aeromonas , aeromonas hydrophila , microbiology and biotechnology , transferrin , edwardsiella ictaluri , immunology , endocrinology , bacteria , fishery , fish <actinopterygii> , genetics
In this study, we assessed the immune status and natural immunity at different ages in channel catfish Ictalurus punctatus raised in ponds in the southeast USA. Sera were obtained from catfish at 2, 3, 4, 6, and 9 months, and 1, 1.5, 2, 3, 4, 5, and 9 years of age. Catfish immunoglobulin M was quantitated by radial immunodiffusion (RID) according to the Mancini technique. Immunoglobulin M (IgM) was detected by RID at 2 months (1.5 mg/mL), and a gradual increase in IgM was seen until 5 years of age (8.2 mg/mL). Ratios of IgM to globulin remained relatively constant until 3 years of age. Bactericidal activity elicited by the alternative complement pathway (ACP) was determined with Pseudomonas , Escherichia , Aeromonas , and Edwardsiella species. Essentially no difference was seen in percent bactericidal activity against Escherichia and Pseudomonas by the ACP among the different ages of channel catfish. The bactericidal percentages were very high (100°10) against both genera except for Pseudomonas at 2 months and 3 months of age. No bactericidal activity (0%) was found against Aeromonas and Edwardsiella at any age, and both are known fish pathogens. Transferrin, an iron‐binding protein, ranged from 1.45 mg/mL in 2‐month‐old catfish to 3.61 mg/mL in 9‐year‐old catfish. Transferrin‐to‐globulin ratios varied from 0.044 at 2 months to 0.070 at 9 years of age. Ratios of total protein and albumin to globulin for the different ages of catfish were determined. Total protein ranged from 41.6 mg/mL in 2‐monthold catfish to 70.1 mg/mL in 9‐year‐old catfish. Albumin increased from 8.8 mg/mL at 2 months to 18.8 mg/mL at 9 years of age. There was no consistent pattern in albumin‐to‐globulin ratios of catfish aged 2 months to 9 years.