Combined Efficacy of Curcuma longa and Spirulina platensis Enhancing Growth, Immunity, Coloration, and Resilience to Ammonia Stress in Balloon Molly, Poecilia sphenops

Turmeric (TUR), Curcuma longa , is rich in bioactive substances, and spirulina (SPR), Spirulina platensis , is a source of protein that is highly digestible. This research investigated the combined effects of dietary C . longa and Spirulina platensis on the growth, nutritional composition, coloration, immunity, and gill health of balloon molly fish, Poecilia sphenops , (initial weight = 0.977 ± 0.003 g) when exposed to acute ammonia stress. Poecilia sphenops (20 fish per aquarium) was distributed into four treatments, each with three replicate aquariums, according to the diets: a basal control diet, a diet supplemented with 0.1% TUR, a diet supplemented with 0.1% SPR, and a diet containing TUR + spirulina 0.1% combined (TUR + SPR). After a 90‐day feeding trial, TUR + SPR showed significantly higher growth indicators (average daily gain ADG and specific growth rate SGR), improved feed efficiency (feed conversion ratio FCR, protein efficiency ratio PER, and protein productive value PPV), enhanced immunity (immunoglobulin M IgM, lysozyme activity, and phagocytic activity PA), and more vibrant coloration compared to other treatments. The SPR showed improved growth and coloration parameters, also greatest increases in head and caudal peduncle dimensions, while TUR + SPR produced the largest overall increases in body width and length ( p < 0.05). Histological analysis of the gills after exposure to acute ammonia stress at the end of the study showed moderately abnormal tissue in TUR, mildly altered tissue in SPR, and normally differentiated tissue in TUR + SPR. Although both TUR and SPR have been individually investigated as feed additives in various fish species, their combined effects, particularly in ornamental fish, remain largely unexplored. The specific knowledge gap addressed by the present study is whether the combination of TUR and SPR at a low inclusion level (0.1% total additives) can simultaneously enhance growth, feed utilization, skin pigmentation, immune parameters, and gill resilience to acute ammonia stress in balloon mollies.