Nutrient‐Density Gradients, Laying Performance, and Yolk Lipid Responses in Hens Fed Fermented Pangasius By‐Product Diets

Using fish-processing residues in poultry diets requires assessment of performance alongside the nutrient changes caused by ingredient substitution. We evaluated six practical diets in 150 Hisex Brown laying hens (30 cages; five independent cages per diet) over 60 days: a basal control, four diets containing 0.5–2.0% fermented Pangasius by-product extract formulated with sugar palm starch, and a canthaxanthin reference. Cage-level responses were analyzed with one-way analysis of variance, and nutrient-density descriptors were calculated from formulation records. Hen-day production differed among diets (p = 0.0053), with means of 61.91% in the basal control and 80.36% at 2.0% inclusion; the overall feed conversion ratio did not differ significantly (p = 0.294). Across the graded series, calculated energy-to-crude-protein density rose from 16.22 to 16.86 kcal/g protein and the dietary omega-6:omega-3 ratio from 12.84 to 14.41, whereas the measured yolk omega-6:omega-3 class ratio fell from 11.57 to 9.69. Yolk cholesterol means declined from 1384.1 to 995.6 mg/100 g dry matter. These findings support multi-criterion screening of practical alternative-feed formulations but cannot establish a nutrient optimum or an isolated effect of the fermented preparation.