Optimization of Thermal Shock Protocols for Induction of Triploidy in Brook Trout

Abstract

Abstract Techniques for production of triploids are well described for commercially reared salmonids (e.g., rainbow trout Oncorhynchus mykiss and Atlantic salmon Salmo salar). Among less commonly used species, including brook trout Salvelinus fontinalis, these protocols have not been optimized. As a prelude to investigating the regional potential for commercial culture of brook trout with all-female and all-female triploid stocks, we conducted experiments to test the effects of the primary variables of thermal shock used to induce retention of second polar bodies. The objective was to identify a protocol that maximizes yield of both triploid and gynogenetic diploid progeny. The first experiment measured survival of gynogenetic embryos produced by heat shocks involving combinations of different temperatures (26, 27, 28, or 29°C) and durations (7, 10, 13, 16, 19, or 22 min). In three subsequent experiments, production of triploids was assessed for thermal shocks involving variable times of initiation (7, 10...