231. Effects of Water Temperature and Curcumin-piperine Supplementation on Growth Performance and Carcass Traits in Juvenile Rainbow Trout.

Abstract Thermal stress can reduce overall growth and efficiency in various aquaculture species. Rising water temperatures, especially for cold-water species such as rainbow trout (Oncorhynchus mykiss), can accelerate metabolic rates, change energy allocation, and increase oxidative load. Curcumin, a turmeric-derived polyphenol, has antioxidant and anti-inflammatory properties, although typically has low bioavailability. Several studies have observed that piperine, a black-pepper extract compound, can be utilized as a co-supplement and can increase the bioavailability of curcumin and enhance its effects. The objective of this study was to evaluate how a combination, dietary supplement of curcumin (0.7%) and piperine (0.3%) influences growth performance, carcass yield, and tissue indices in juvenile rainbow trout reared under optimal and elevated water temperatures. Juvenile rainbow trout were placed into a 2 x 2 factorial design with temperature (14 °C vs. 19 °C) and diet (control vs. curcumin-piperine) for 9 weeks. Fish were blocked by initial body weight (LW, MW, HW) and were distributed across replicate tanks (6 tanks per treatment; 10 fish per tank). Fish were anesthetized with MS-222 and individually PIT tagged intraperitoneally with 8mm tags after acclimation and were given 2 weeks to heal prior to the start of the study. Throughout the study fish were fed twice daily to apparent satiation. Body weight was monitored throughout the study. At the end of the study, total body weight, length, empty carcass weight, fillet weight, and hepatosomatic index (HSI) were collected. White muscle and liver samples were collected and preserved for downstream RNA extraction and gene expression. Data were analyzed in the mixed model of SAS with treatment, temperature, treatment x temperature in the model; tank was included as a random effect, and body length added as a covariate for appropriate variables. Elevated temperatures affected several growth metrics after adjustment for body length as a covariate. Trout reared at elevated temperatures (19 °C) had a significantly (P < 0.05) higher empty carcass weight, fillet weight, and condition factor in comparison to fish reared at optimal temperatures (14 °C). Curcumin-piperine supplementation did not (P > 0.05) impact body weight or carcass yield. However, supplemented fish exhibited higher (P < 0.05) hepatosomatic indices and higher (P < 0.05) liver weights in comparison to control fish, potentially indicating altered energy distribution. Temperature x treatment interactions were insignificant (P > 0.05) across all traits. These results point to growth benefits from short-term exposure to elevated temperatures in juvenile rainbow trout. While the curcumin and piperine combination supplement did not directly influence growth performance, it did impact hepatosomatic index and liver weight potentially altering fish metabolism instead of directly altering muscle development.