Aquaculture America 2024

February 18 - 21, 2024

San Antonio, Texas

IT’S GETTING HOT IN HERE: AN INVESTIGATION INTO THE ENVIRONMENTAL PLASTICITY OF LARVAL ZEBRAFISH Danio rerio

Lauren George*, Aubrey Dissinger, Karolina Kwasek

Southern Illinois University - Carbondale

1125 Lincoln Dr, 62901, Carbondale IL

lauren.george@siu.edu

 



Ectothermic f ish can be characterized by a certain degree of environmental plasticity and many of their traits related to behavior, stress response, and social skills can be influenced by early life experiences. These plastic responses provide different species with a coping mechanism to changing environmental conditions with epigenetic alterations in DNA seeming to play a major role. Ho wever, the mechanisms behind the induction of the adaptation process and environmental plasticity are not well understood .  The main objective of this study was to use zebrafish (Danio rerio) as a model to determine if exposure to high temperatures at the larval stage can cause phenotypic plasticity, and how this could affect factors including growth, survival, and food conversion ratio (FCR) when exposed to similar conditions later in life.

 Two treatments of zebrafish were randomly distributed into 6 (3L) tanks at 3 days post-hatch (dph), with 120 larvae per tank. This study initially included two treatment groups for the environmental programming : 1) an  environmental control (EC) treatment, which remained at the control temperature of 26° C;  and 2) an  environmental programmed  (EP)  treatment which was raised to 32 °C  for a 24hr period between 6-8dph, then returned to 26 °C. Both treatments continued with a grow-out period to 35 dph  at 26°C . At 35pdh,  the initial treatment groups were split in half and randomly distributed into four treatments with 11 fish per tank for the environmental challenge . The treatment groups were:  1)  both  EP  and EC  raised at 32°C  from 35-57dph (EP-32 and EC-32) ;  2) EC and EP  raised at optimal  temperature of 26°C from 35-57dph (EP-26 and EC-26). All groups were fed at a restricted feeding rate during the challenge phase equal across all treatments.

 During the environmental challenge, the numerical data indicated the EP-32 group  tended to have higher individual weight gain compared to the EC-32. The EP-26 group also  tended to have  higher  individual weight gain compared to the EC-26. In addition, t he EP-32 group tended to have  the lowest FCR, particularly in comparison to EC-32 . These preliminary results  potentially  suggest that brief exposure to high water temperature induced  at the larval stage may lead to improved feed utilization and growth in zebrafish when exposed to  similar temperatures at a later stage.  The statistical and  gene expression  analyses  will be included in the oral presentation.