The effects of the dietary biotin on zebrafishDanio rerioreproduction

Abstract

AbstractAn experiment was conducted to investigate theeffects of dietary biotin on zebrafish Danio rerioreproduction. Biotin and avidin (biotin antagonist)were added to two isonitrogenous and isocaloricpurified diets to provide molar avidin:biotin ratiosof 0:1 (biotin-sufficient diet) and 120:0 (biotin-unsufficient diet). Each diet was fed to a group ofmales mean initial mass 0.262 g) and a group offemales (mean initial mass 0.285 g) for 99 days.Following this feeding period, males fed biotin-sufficient diet exhibited higher gonado-somaticindex, sperm density, sperm motility and spermviability than those fed biotin-unsufficient diet(P < 0.05). In the presence of biotin-sufficientmales, biotin-sufficient females spawned more eggs(222.2 eggs) than biotin-deficient females (18.8eggs) (P < 0.05). The same pattern was observedwith biotin-deficient males (7.6 vs. 1.8 eggs)(P < 0.05). Biotin-sufficient males generated ahigher percentage of fertilized eggs (90% vs. 42%),hatching rate (62% vs. 27%), larvae survival(98% vs. 37%) and larvae length at 7 days postfertilization (4.4 mm vs. 4.2 mm) than biotin-deficient males (P < 0.05) . Biotin status of themale is of high consideration for successful breed-ing in zebrafish, because it significantly impactsthe reproductive performances of the female.Keywords: Biotin, gonado-somatic index, repro-ductive performance, spermIntroductionBiotin, a water-soluble B-complex vitamin, is anessential nutrient for fish (Shaik Mohamed,Ravisankar & Ibrahim 2000; Halver 2002). Biotinhas been recognized to serve as a covalentlybound coenzyme for four carboxylases:acetyl-CoAcarboxylase (isoforms alpha and beta; E.C.6.4.1.2), pyruvate carboxylase (E.C. 6.4.1.1),propionyl-CoA carboxylase (E.C. 6.4.1.3) and3-methylcrotonyl-CoA carboxylase (E.C. 6.4.1.4)(Dakshinamurti 1994, 2005; Maeland, Waagbo,Sandnes & Hjeltnes 1998; Shiau & Chin 1999;Shaik Mohamed 2001; Rodriguez-Melendez Z Li, Zhang, Mai, Ai, Wan, Zhang Z Maeland et al. 1998; Shiau & Chin1999; Shaik Mohamed et al. 2000; Rodriguez-Melendez & Zempleni 2003; Li et al. 2010).In mammals, it has been found that biotindeficiency negatively impacts spermatogenesis(Dakshinamurti 2005; Cammalleri, Bentivegna M Delost & Terroine 1956). Delayed spermato-genesis and decreased number of spermatozoa inrats were also attributed to biotin deficiency (Terro-ine 1961; Dakshinamurti 2005). More recently,biotin deficiency was found to decrease the fertilityof fruit flies Drosophila melanogaster (Landenberger,Kabil, Harshman & Zempleni 2004).However, despite the extensive studies con-ducted on biotin requirements for maximum