Yolk Colour Development, Plateau Stability and Post-Withdrawal Depletion with Marigold, Paprika and Annatto Pigments in Laying Hens

Background: Natural botanical pigments can enhance egg yolk colour, but their temporal responses during supplementation and after withdrawal may differ. Aims: This study evaluated the comparative pigmentation kinetics, plateau stability, and post-withdrawal depletion of three natural plant pigment sources in laying hens. Place and Duration of Study: This study was conducted at the Poultry Research Station, Madhavaram Milk Colony, Chennai-51, Tamil Nadu, India, over a total experimental period of 90 days. Methodology: Thirty Rhode Island Red laying hens (42 weeks old) were allocated to three dietary treatments: dried African marigold petal powder (MPP; 1.0%), annatto seed powder (ASP; 1.0%), or paprika pepper powder (PPP; 0.1%). Following a 6-day baseline period (Periods 1–3; 3 periods × 2 days), the respective supplemented diets were provided for 28 days (Periods 4–17; 14 periods × 2 days), followed by an unsupplemented withdrawal phase. Yolk colour was evaluated using a DSM Yolk Fan. Dietary supplementation significantly influenced yolk colour, with significant main effects of treatment (P < .001) and time (P < .001), as well as a significant treatment × time interaction (P = .0077). Results: Marigold induced the fastest colour development and the highest colour intensity, reaching a DSM yolk colour score of ≥8 by Period 7 (Days 13–14; 6 days after the start of supplementation) and peaking at 10.07 in Period 16, representing a 101.07% increase from baseline. Paprika reached a DSM score of ≥8 by Period 9 (10 days after the start of supplementation) and peaked at 8.50 in Period 13, an 88.35% increase from baseline, whereas annatto reached a score of ≥8 by Period 8 (8 days after the start of supplementation), peaked at 8.50 in Period 9, and subsequently declined despite continued supplementation. Near-maximum colour (≥95% of the treatment-specific peak) was maintained for 16 days by paprika, 14 days by marigold, and 12 days by annatto. Following withdrawal, paprika exhibited the greatest colour retention, maintaining a DSM score of ≥8 for 8 days, compared with 2 days for marigold and 0 days for annatto. Conclusion: Overall, the three pigment sources exhibited distinct combinations of response characteristics: marigold provided the fastest colour development and highest colour intensity, whereas paprika showed greater plateau stability and post-withdrawal persistence. These findings indicate that evaluation of dietary pigment sources should consider depletion dynamics alongside peak colour response when selecting pigments for consistent yolk colour in specialty egg production.