This study was carried out for 60 day. A total number of 70 fish (Cyprinus carpio L.) with an average of 13.40±1.85 g and a length 11.07 ±1.27 cm were randomly divided into five treatments as a two tank treatment, similar to its contents of conventional ingredients (i.e., fishmeal, soybea soybean meal, corn, barley and wheat bran as well as vitamin mixture premix and carboxy methyle celloluse (CMC)). They differ in their content from food additives. They were commercially ready made in dietary T1 and T2 (Thepax 0.5, 1 gm/ kg), T3 and T4 (Labazyme 1, 2 gm/ kg) and control (0.0 gm/kg) of experimental diets. Data collected included fish weight and feed conversion ratio measured at the end of the study. The results found that the addition of food additives has significantly been affected by weight gain, specific growth rate and feed conversion ratio (P<0.05), with the best results obtained in fish food additives, pellets have been supplemented to Thepax 1 gm/ kg to enhance growth and immune responses.

The present study was carried out to assess the effect of diet supplemented with thepax on intestinal morphometry of young Cyprinus carpio. Fish mean weights were 13.40±1.85 gm and their mean total length 11.07±1.27 cm (30 specimens), which were randomly distributed into three treatments (two replications for each treatment). Fish groups were fed three dissimilar diets up to 60 days. The first group was fed with 0.5 gm thepax/kg diet, the second group was fed with 1 gm thepax/kg diet and the third group was served as the control group which fed basal diet without thepax.supplementation. The feed was applied twice daily at 3.0% of the body weight per day for 60 days. The intake of prebiotics (thepax) modified the gastrointestinal tracts. Villus length, villus width, and villus area were significantly (P<0.05) higher than control in young common carp fed the diet supplemented with thepax (1 gm/kg). No differences in liver histology are observed between the three experimental feed treatments. No histopathological changes like degeneration, necrosis, leukocyte infiltration, haemorrhage and steatosis were noticed. These results indicated that host-derived prebiotics, especially thepax (1 gm/kg) has significant potential as an important prebiotic to enhance the nutrients utilization and metabolism through increasing intestinal surface area in young common carp.