Turmeric (Curcuma longa) affects growth, nutritional physiology and hematology of Oreochromis niloticus

Abstract Background Use of antibiotics as growth promoters in aquaculture, leads to resistant bacteria. There is need for plausible alternative like phytogenic ingredients without residual effects nor leading to resistant bacteria. Turmeric ( Curcuma longa ) is a plausible alternative. We formulated five diets, feeds F1 to feeds F5, that varied in their turmeric inclusions as follows; F1, 20%, F2 15%, F3 10%, F4 5% and F5 0%, and F6 was control. Ingredients were mixed according to design and preconditioned at 120 °C, pelleted, and dried in an electric oven at 40 °C to 9% wet weight. Oreochromis niloticus fingerlings of initial weight 0·933 g were stocked at 15 fish per 15 liter aquaria (14 g/15liter) and fed for 70 days with the experimental diets. Results The O.niloticus that received 20% turmeric supplement had the best SGR of 4.10 ± 0.07% day −1 ( p < 0.05), ( p = 0.06), while O.niloticus that received 0% turmeric had least SGR 2.51 ± 0.06% day −1 . The SGR reduced as the inclusion level of turmeric in the diet was reduced.The O.niloticus mucosal fold microvilli seems to increased more in length and width, portending more absorbent surface as turmeric supplements inclusion level increased. Liver cell showed normal liver histology architecture with hepatocytes (Hp) separated by sinusoids and normal vacuolated cells. The O. niloticus ALT (Alanine aminotransferase) and AST (Aspartate aminotransferase) seems to be reducing as the inclusion level of turmeric increase. Blood cholesterol level also seems to reduce with increase in turmeric inclusion level. Conclusions Turmeric seems to enhances digestion and increase growth rate of fish. Turmeric inclusions also seems to enhance elongation and broadness of mucosal fold microvilli. Increase microvilli could translated to higher absorptive surface, uptake of nutrient and growth. There seems to be no deleterious effects on the liver and gut health.