Effects of dietary administration of Nettle leaves (Urtica dioica) hot water extract on health indices and immunity in Litopenaeus vannamei exposed to Vibrio harveyi

This study investigated the effects of Urtica dioica (Nettle) on health indices, including total hemocyte count (THC) and differential hemocyte count (DHC), total plasma protein (TPP), and glucose level of hemolymph when the Litopenaeus vannamei was fed with diets containing different hot water extract concentrations of U. dioica (10, 50, and 100 mg kg-1) for 40 days. After 14 days of exposure to Vibrio harveyi, the survival rate was determined. The results showed that the use of U. dioica extract led to a significant increase in the health indices, (THC and DHC). The significant increase (p≤0.05) was observed in the frequency of small and large granular hemocyte, as well as in the biochemical indices, the number of hyaline cells, TPP, and glucose level, particularly at higher concentrations of the extract. After 14 days, the survival rate of the shrimps fed with a diet containing 50 mg kg-1 of U. dioica extract, showed a significant difference from other experimental groups. Overall, the hot water extract of the U. dioica can improve health indicators, THC, TPP, and glucose levels, and also increase the survival rate of the shrimp infected with V. harveyi.