The effects of 17α-methyltestosterone administration on spermatophore quality in captive broodstock of tiger shrimp Penaeus monodon were investigated using injection method and oral method based on the optimized protocol. The experiment was designed to compare the oral administration group and injection group with two replications during a 38-day experimental period. Captive male broodstock of tiger shrimp weighing 57-95 g was collected from ponds and stored in a 10,000 m3 concrete tank (20 shrimp/tank). Male broodstocks were injected and orally administrated with 17α-methyltestosterone at the dose of 300 ng/100 g body weight. Data indicates that the injection of 17α-methyltestosterone showed the percentage of mature broodstock count and the percentage of normal spermatozoa count 1.07 and 1.38% higher and significantly differs from oral administration through mixing in feed at the maturation stage. However, at the time of the maturation and 1st re-maturation of both the methods, the weight of the spermatophores and the number of spermatozoa did not show any difference. Based on the comparison of the two methods used, the results are obtained that the administration of the hormone 17α-methyltestosterone can be done both through mixing in feed and through injection, but the administration of hormones through injection gives better results than the broodstock matures first simultaneously.
This study aimed to evaluate the effect of dsRNA VP24 application on different stages of larvae. For mass production, cloned recombinant bacteria carrying the construction of the promoter T7VP24 are planted in Luria Bertani broth medium. The bacteria were inactivated using the heat-killed bacteria method by immersion in water at 80 °C for 5 minutes. The inactivated bacteria were mixed with larval commercial feed. The nauplii were produced from broodstock from Aceh waters and reared until postlarva 12 (PL12). The feed containing the dsRNA vaccine was applied to a different stage of larva, i.e: starting from zoea 1 (A), mysis 1 (B), PL 1 to PL 12 (C), and control without dsRNA (D). The PL 12 were challenged with WSSV by the immersion method and morphological characters were assessed. Results showed that inactivating bacteria was effectively done by immersion method without damaging the dsRNA construct in the plasmid. The survival rate was significantly influenced by different stages of larvae (P 0.05), in which the highest survival (26.0%) was obtained from mysis. The highest value of morphological characters (92.3) was also inhibited in the mysis. The results suggested that the dsRNA vaccine for larvae could be started to be applied in the mysis stage.
The morphological difference of tiger shrimp, Penaeus monodon from Aceh waters is limited to explore for female and male discrimination using morphometric analyses. The study aimed to evaluate the morphological characters between female and male tiger shrimp using traditional and truss measurements. A total of 57 samples (39 females and 18 males) were analysed using 9 characters for traditional morphometric and 40 characters for truss morphometric. Multivariate analyses were applied to reveal the morphometric variation between male and female populations. The result of principal component analysis indicated that 4 characters, i.e: carapace length (CL), carapace width (CW), rostrum length (RL), and sixth segment length (SL6), were significantly different (P<0.05), while three truss morphological characters, i.e: distance between anterior and posterior carapace, distance between ventral posterior sixth segment to telson end, and distance between anterior and posterior second segment, were significantly discriminated (P<0.05) between female and male of tiger shrimp. Overall, 94.9% of the male and 88.9% of the female individuals were assigned to their native populations using traditional morphometric analysis, while truss morphometric was 87.2% and 88.9%, respectively. The individual proportion of 93.0% was properly classified into their original population group for traditional morphometric and 87.7% for truss morphometric characters.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.