Methyltestosterone 17α- injection as a safe alternative way to enhance maturation and immune response of tiger shrimp Penaeus monodon transgenic F1

Abstract

The present study investigated the effects 17α-methyltestosterone on the reproductive performance and immune response of broodstock tiger shrimp Penaeus monodon transgenic F1. This study evaluated reproduction, mature spawners, spermatophore weight and density, and total haemocyte count (THC) immune response. Males aged 13 months were divided into four groups. Groups 1, 2 and 3 were injected 17α-methyltestosterone (17α-MT) at the dose of 100, 150, and 200 ng/100 g body weight three times with an interval of one week. Group 4 was eyestalk ablation. The specimen was kept in a concrete maturation tank for 10 tons. Approximately two weeks after the final injection (on the 35^th day), the male subjects were collected, their weights were recorded, and their spermatophores (sperm capsules) were removed. THC was observed before, then on the 7^th, 14^th, and 35^th days of the post-rearing period. 17α -MT induction using dose-dependent increases the percentage of the mature spawner, spermatophore weight, spermatozoa density, and higher total hemocyte count (p>0.05) than eyestalk ablation. The THC injected with 17α-MT at three doses was higher (p<0.05) than ablation on the 7^th and 14^th days. Unlike on the 35^th day, the highest THC was observed at a dose of 200 ng/100 g bw (p>0.05) among all treatments.