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Effect of short-term feeding duration of diets containing commercial whole-cell yeast or yeast subcomponents on immune function and disease resistance in channel catfish, Ictalurus punctatus
- Welker, T. L., Lim, C., Yildirim-Aksoy, M., Klesius, P. H.
- Journal of animal physiology and animal nutrition 2011 v.96 pp. 159
- Edwardsiella ictaluri, Ictalurus punctatus, Saccharomyces cerevisiae, antibodies, antibody formation, bacterial infections, beta-glucans, catfish, digestive system diseases, disease resistance, experimental diets, feed supplements, fish feeding, lysozyme, mannans, septicemia, yeasts
- Juvenile channel catfish, Ictalurus punctatus, were fed diets supplemented with yeast or yeast subcomponents (YYS) as commercial preparations of b-glucan (MacroGard and Betagard A), mannan oligosaccharide (Bio-Mos Aqua Grade), or whole-cell Saccharomyces cerevisiae (Levucell SB20) at the manufacturers’ recommended levels. Fish were fed experimental diets for 1 or 2 weeks prior to disease challenge (prechallenge feeding periods) and sampled at the end of each feeding period to measure haematological and immune parameters and to determine the effects of dietary YYS on resistance to Edwardsiella ictaluri, the causative agent of enteric septicaemia disease (ESC). Feeding of experimental diets continued for 3 weeks post-challenge. In channel catfish fed diets supplemented with MacroGard, Betagard A, or Levucell SB20, survival in the 1 week pre-challenge feeding group and antibody titres in the 2 week feeding group were significantly higher post-E. ictaluri challenge in relation to catfish fed with the control diet. In fish fed these same three diets, survival to ESC was significantly higher after 1 week vs. 2 weeks feeding, while the antibody response was significantly higher after 2 weeks vs. 1 week. Lysozyme activity was also higher in the 1 week feeding group, but the increased activity was unrelated to diet. Feeding YYS-supplemented diets for a shorter duration of 1 week prior to challenge may prove beneficial in increasing resistance to ESC in channel catfish. However, we cannot discount that feeding YYS diets during the recovery period may have contributed to ‘glucan overload’ and reduced survival in the 2 week feeding group.