The objective of this research was

The objective of this research was to determine the effects of vitamin C supplementation in feed on the hematology parameters of Mekong Giant Catfish (Pangasianodon gigas Chevey). Catfish with mean initial weight of 65 ± 2.00 g were randomly placed in 2.4 × 3 × 1.5 m cages in earthen pond. Growth experiments were conducted for 28 weeks. Four levels of vitamin C with three replicates each were tested including 0, 250, 500 and 750 mg kg-1 of feed. Glucose and total protein in serum were measured. Hematocrit, red blood cells, white blood cell count, and lysozyme activity of serum were examined. Fish received vitamin C supplemented diets gave higher weight gain. Catfish fed with vitamin C supplementary diets showed greater innate immunity response of Mekong giant catfish. The catfish received 500 and 750 mg vitamin C kg-1 supplementary diets showed the best records of hematocrit, red blood cell count, serum lysozyme, serum protein and serum glucose. These were significantly different from fish fed a basal feed with no additional vitamin C. But the increased in cost with no gain in performances was observed in catfish fed with 750 mg vitamin C kg-1 supplementary diet over those fed with the other levels of vitamin C tested. It was concluded that a minimum amount of 250 mg vitamin C kg-1 is sufficient to be added in diet for good growth performances and immune response of Mekong giant catfish. © 2012 Friends Science Publishers