<div>Background: The present study explored the possibility of using live feed, as vector for supplementing the androgenic hormone in aquaculture seed production.&nbsp; 
 
Methods: The study consisted of five treatment doses of 17&alpha;-methyl testosterone namely; control (without hormone), T1 (20 mg L-1), T2 (40 mg L-1), T3 (60 mg L-1) and T4 (80 mg L-1) and each were triplicated. The doses were tested in the live feed of Artemia nauplii and rotifer by following completely randomized design. The Artemia nauplii (Artemia salina), collected by hatching the Artemia&nbsp;cyst and 5-8 days old rotifers, collected from mass culture unit of rotifer, were released in their respective treatment doses at 100 and 800 individuals/ml, respectively.&nbsp; 
 
Result: The study found significant difference in accumulation of hormone in the tissues of live feed at different time intervals. In Artemia, significantly higher amount of 17&alpha;-MT (15.33&plusmn;0.09 mg L-1) was observed in 80 mg L-1 group at 24 h. In rotifer, significantly higher value of 17&alpha;-MT (17.42&plusmn;0.06 mg L-1) was recorded in 60 mg L-1 group at 6 h. The level of 17&alpha;-MT in Artemia nauplii and rotifer started showing a decreasing trend in 24 h and 6 h, respectively. Overall the findings of the present study support that supplementation of hormone through live feed is possible as live feed accumulated 17&alpha;-MT in its tissue after enrichment which can be further explored for producing all-male population in a more sustainable way.&nbsp;</div>

Optimization of 17&alpha;-Methyl Testosterone Dose in Artemia Nauplii and Rotifer using Enrichment Technique

Background: The objective of the study was to examine the growth and development of M. pancalus larvae in captive conditions, including pigmentation patterns, yolk and oil globule utilization, growth rates and metamorphosis, as well as to identify suitable live food for larviculture. 
 
Methods: The larvae, produced through induced breeding, were kept unfed until the yolk-sac absorption and then fed with freshwater rotifer, mixed zooplankton and Tubifex worms at different stages of development. The larvae were reared in indoor glass tanks and outdoor reinforced plastic tanks to document their morphological and chronological development. 
 
Result: The findings showed that the larvae exhibited typical characteristics of eel. Notably, dentition was observed before yolk resorption, indicating the highly predatory nature of the larvae. The bands of melanophores, which were prominent at the beginning, disappeared between 5-7 days post-hatch. Additionally, the study identified distinct features of spiny eels, such as a trunk-like rostral projection at 14 days post-hatch and erectile dorsal spines at 21 days post-hatch. The growth pattern, morphological changes and adaptation to benthic burrowing habits indicated that the larvae metamorphosed into the fry stage between 28-45 days post-hatch. These results provide valuable insights into the ontogenetic development and rearing of M. pancalus and can be used to support future aquaculture and conservation programs.

Optimization of 17α-Methyl Testosterone Dose in Artemia Nauplii and Rotifer using Enrichment Technique

Ontogeny and Growth of Early Life Stages of Barred Spiny Eel Macrognathus pancalus (Hamilton, 1822)