Effects of Feeding Triiodothyronine on Growth, Food Conversion and Disease Resistance of Goldfish, Carassius auratus (Linn.)

摘要

The effect of inclusion of 3,3',5-triiodo-L-thyronine (T_3) at 0, 1.25 and 6.25 ppm in the diet was examined in goldfish Carassius auratus young ones. The 60-day feeding trial brought about significant (p<0.05) increase in specific growth rate, per cent body weight gain, food conversion efficiency and protein efficiency ratio at both the levels of incorporation of T_3 than the control (0 ppm feed). The final weight and net weight gain were significantly raised at the higher level of T_3 incorporationin the diet only than the control. However, there was no difference in these parameters at two different levels of T_3 incorporation. The survivability obtained against intraperitoneal challenge with pathogenic bacteria Aeromonas hydrophila on day 60 were 16.67, 66.67 and 33.33% in 0, 1.25 and 6.25 ppm T_3 inclusions, respectively. The result suggests that in the goldfish T_3 stimulated growth and disease resistance. High doses of T_3 had less beneficial effect on survival than the lower dose (1.25 ppm) thus indicating the lower level of inclusion in the diet for growth and disease resistance.