Stocking density modulates tilapia (Oreochromis niloticus) performance and fillet quality through phospholipid remodeling

This study evaluated the effects of different stocking densities (high density-HD: 14 fish/tank; low density-LD: 7 fish/tank) on productive performance, lipidomic profile, and fatty acid composition in GIFT tilapia juveniles. Zootechnical parameters were analyzed, including relative growth, weight gain, feed conversion ratio, and fillet yield, along with lipidomic markers and fatty acids. Results showed that high density promoted better apparent feed conversion (p < 0.0001). However, low density led to higher apparent feed intake (p < 0.0001) and greater fillet yield (p = 0.0009), suggesting these fish utilized ingested nutrients to maximize fillet production. Lipidomic analysis revealed higher phospholipid turnover in low density (LD), with increased lysophosphatidylcholines (LPC) and lysophosphatidylethanolamines (LPE), while high density (HD) showed phosphatidylcholine (PC) accumulation, indicating less efficient lipid metabolism under stress. Additionally, LD had higher concentrations of polyunsaturated fatty acids (PUFAs) (p < 0.05), highlighting density's influence on nutritional quality. We conclude that low stocking density suggests an improvement in productive performance and fish quality, whereas high density induces metabolic responses indicative of chronic stress related to lipid metabolism.