A comparison of the effects of eyestalk ablation and Ovaprim hormone injection on the process of maturation, histological study and biochemical composition of Litopenaeus vannamei

In the present study, we evaluated the effects of eyestalk ablation, Ovaprim hormone injected and sterile vehicle solution injected (control) on maturation, Ovarian tissue and biochemical changes in Litopenaeus vannamei. Sterile vehicle solution and hormone injections at 500 and 1000 ng/g body weight were performed with a 100 μl volume in three steps (0, 7 and 14 days). We examined 60 females at 4 treatments for 30 days. The apparent observation and histological studies showed that the highest percentage of the adult females and mature oocytes were related to eyestalk ablation treatment. We analyzed biochemical compounds (protein, lipid and carbohydrates) hemolymph, and body muscles at three stages of sampling (immature, maturation and after spawning). At different stages of sexual devlopment, significant differences in hemolymph and muscle amount of protein were observed between treatments (P<0.05). In three stages of sampling, the highest amount of protein in the hemolymph and muscle were observed in the eyestalk ablation and hormone injection treatments; we observed the lowest in the saline injection treatment. In each sample, the lipid contents in the hemolymph and muscle significantly differed between experimental treatments (P<0.05). Hemolymph of carbohydrate content significantly differed only at the time of sexual maturation (P<0.05).