The effect of dietary gelatinized ratios at different dietary energy levels on growth and characteristics of blood in carp fingerlings

In order to investigate the effect of dietary gelatinized ratio (GR) and digestible energy (DE) content on the growth and blood profile of carp, fingerlings (8.5g on average) were fed low (DE: 253-393kcal/100g) or high (DE: 323-448kcal/100g) energy diets with different levels of GR adjusted using raw and extruded potato starch at a 40% level. The growth was highest in fish fed on a low energy diet with 40% GR and a high energy diet with 20% GR. Daily feed consumption was inversely related to the dietary GR levels. Feed efficiency and protein efficiency ratio were improved by elevation of dietary GR at both energy levels. The apparent digestibility of dietary lipid was not influenced by GR levels at low energy diets, but slightly by elevation of GR in high energy diets. On the other hand, the digestibility of starch and energy increased along with an increase a dietary GR levels in both the energy levels. Blood parameters were also affected by both dietary GR and energy levels. A mixture of raw and gelatinized starch seemed to be suitable as a carbohydrate source in the diet for carp.