ISSUE FOCUS FEED & ADDITIVE MAGAZINE August 2025 69 Return on investment was calculated at approximately 7:1 in the NQ top-up group, underlining the economic value of the additive. The matrix group, despite the lower protein and energy content, demonstrated equal or better survival and protein efficiency than the control, clearly showing that NQ not only improves performance but also supports cost-saving strategies through nutrient optimization. IMPROVING GUT HEALTH AND DIGESTIVE EFFICIENCY The trial also examined the impact of NQ technology on intestinal morphology and digestive health, two key pillars of feed efficiency and overall fish productivity. The histological analyses were performed in the Faculty of Veterinary Medicine of Cairo University. Histological analysis of the intestine revealed significant improvements in gut architecture in fish receiving NQ. Villus height and surface area were markedly increased, suggesting a greater absorptive capacity. The ratio of villus height to crypt depth, a widely accepted marker of gut health and regeneration, was also improved, indicating a more balanced and functional intestinal lining with less evidence of cellular stress. In parallel, blood enzyme analyses supported these findings. Fish receiving NQ showed increased activity of digestive enzymes, notably amylase and lipase, reflecting improved capacity to break down and utilize carbohydrates and fats. Moreover, reduced levels of uric acid, triglycerides, and very-low-density lipoproteins (VLDL) pointed to more efficient metabolism of proteins and lipids. These combined improvements in gut morphology and enzymatic function contribute directly to better nutrient absorption, improved growth, and reduced feed waste — key indicators of sustainable and profitable production. STRENGTHENING IMMUNITY AND RESILIENCE Beyond performance and digestion, fish health is a central concern in modern aquaculture, especially for warm-water species like tilapia, which are prone to opportunistic infections under stress. In this context, NQ technology showed meaningful benefits on oxidative balance and immune competence. Oxidative stress was significantly reduced in the NQ groups, as shown by lower concentrations of malondialdehyde (MDA), a key biomarker of lipid peroxidation. In addition, fish receiving NQ had numerically higher total antioxidant capacity, indicating a stronger internal defense system against reactive oxygen species and related cellular damage. Immune function also showed improvement. The albumin-to-globulin (A/G) ratio, which reflects the balance between structural proteins and immune-related globulins, was higher in the NQ groups, suggesting improved immunocompetence. Furthermore, lysozyme activity - a frontline defense mechanism of the innate immune system - was elevated, indicating enhanced ability to combat bacterial pathogens. These parameters together demonstrate that NQ contributes not only to performance and digestion but also to health resilience, reducing the need for therapeutic interventions. Gut Morphology Length (µm) * * 400 350 300 250 200 8,5 8,0 7,5 7,0 6,5 6,0 60 55 50 45 40 35 30 NC NC NQ on-top NQ on-top NC NQ on-top NC NQ on-top VH:CD Depth (µm)
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