Controlling the cannibalism of African catfish juvenile by 17β‒estradiol hormone administration and the stocking density determination

Abstract

An effort to increase the production of juvenile catfish is limited by the high mortality rate, especially caused by cannibalism. The hormonal treatment has been conducted as an effort to control cannibalism. This study used completely randomized factorial design, consisted of six treatments and three replications. There were two factors examined in this study, the first factor was different doses of 17β‒estradiol hormone (0, 30, and 60 mg estradiol‒17β/kg) incorporated in the feed, and the second factor was stocking density (150 and 300 fish/m2). Juvenile catfish with the size of 4.0 ± 0.1 cm were reared for 30 days in the 84 L aquarium. The results showed that hormone treatment could reduce cannibalism rate, type-I and II cannibalism compared to control (P<0.05). The results showed that the lowest of mortality was obtained in the treatment B (17β‒estradiol administration of 30 mg/kg, at stocking density of 150 fish/m2; P<0.05). The lowest cortisol level was found in treatment F, and the highest estradiol level was found in treatment F (17β‒estradiol administration of 60 mg/kg, at stocking density of 300 fish/m2; P<0.05). The lowest of blood glucose level was found in treatment B (P<0.05). The highest specific weight growth was found in the stocking density of 150 fish/m2 (P<0.05). The results of this study indicated that administration of 17β‒estradiol in feed could reduce the level of cannibalism in African catfish juvenile.
 Keywords: cannibalism, Juvenile, catfish, estradiol‒17β, cortisol
 
 ABSTRAK
 
 Upaya untuk meningkatkan produksi benih ikan lele dibatasi oleh tingginya angka kematian, terutama yang disebabkan oleh kanibalisme. Pendekatan hormonal telah dilakukan sebagai upaya pengendalian kanibalisme. Penelitian ini menggunakan rancangan acak lengkap faktorial, terdiri dari enam perlakuan dan tiga ulangan. Ada dua faktor yang diteliti dalam penelitian ini, faktor pertama adalah dosis hormon 17β‒estradiol yang berbeda (0, 30, dan 60 mg/kg) yang diberikan melalui pakan, dan faktor kedua adalah padat tebar (150 dan 300 ekor/m2). Benih ikan lele berukuran 4.0 ± 0.1 cm dipelihara selama 30 hari di akuarium (84 L). Hasil penelitian menunjukkan bahwa perlakuan hormon dapat menurunkan tingkat kanibalisme tipe‒I dan II dibandingkan kontrol (P<0.05). Hasil penelitian menunjukkan bahwa mortalitas terendah diperoleh pada perlakuan B (pemberian 17β‒estradiol 30 mg/kg, pada padat tebar 150 ekor/m2; P<0.05). Kadar kortisol terendah ditemukan pada perlakuan F, dan kadar estradiol tertinggi ditemukan pada perlakuan F (pemberian 17β‒estradiol 60 mg/kg, pada padat tebar 300 ekor/m2; P<0.05). Kadar glukosa darah terendah ditemukan pada perlakuan B (P<0.05). Pertumbuhan bobot spesifik tertinggi ditemukan pada padat tebar 150 ekor/m2 (P<0.05). Hasil penelitian ini menunjukkan bahwa pemberian hormon 17β‒estradiol dengan dosis 30 mg/kg pakan, dan padat tebar 150 ekor/m2 dapat menurunkan tingkat kanibalisme pada benih ikan lele di Afrika.
 
 Kata kunci: kanibalisme, juvenil, lele, 17β‒estradiol, kortisol

Immersion Effect of Estradiol-17β on Cannibalism of Asian Redtail Catfish (<I>Hemibagrus nemurus</I>) Post Larvae

“…Furthermore, Faizati et al (2021) revealed that stocking density affects the survival of Asian redtail catfish seeds, and one of the death causes is cannibalism. The results of this study are in line with Siregar et al (2021), where the administration of estradiol-17β gave catfish seed viability at high stocking densities by suppressing normal mortality, providing fitness for fish with low cortisol. However, this condition was different from Król et al (2014b) which stated that the administration of estradiol had a negative impact on fish survival.…”

“…This decrease occurred as a result of a negative feedback mechanism (Dinsdale and Ward, 2010). Several types of fish are also known to experience a decrease in testosterone concentration after estradiol-17β administration (Yuan et al, 2012;Khara et al, 2013;Siregar et al, 2021). Increased levels of estrogen cause suppression of testosterone levels in the body (Kim and Park, 2012).…”

“…The aggressive behavior of cannibalism is closely related to the role of hormones, one of which is testosterone. In general, there are two hormonal approaches to reduce cannibalism in fish, namely through the steroid hormone pathway in the form of estradiol (Filby et al, 2012;Brown et al, 2014;Siregar et al, 2021) and amino acids in the form of tryptophan (Muslimin et al, 2011;Król and Zieliński, 2015).…”

“…Several studies regarding the role of estradiol in reducing fish cannibalism have been described by Siregar et al (2021) where enrichment of feed with the estradiol-17β could reduce the level of cannibalism in African catfish (Clarias gariepinus). Furthermore, there was also a decrease in aggressiveness with the administration of estrone and estradiol in Pimephales promelas (Dammann et al, 2011), environmental estrogen (EE2) which reduced the aggressiveness of zebrafish (Filby et al, 2012), 17α-ethinyl estradiol in male zebrafish Danio rerio (Colman et al, 2009), and the phytoestrogens-sitosterol and genistein in Betta splendens (Brown et al, 2014).…”