The Effects of Black Tea Factory Waste Supplementation into Laying Hen Diets on Performance, Egg Quality, Yolk Peroxidation, and Blood Parameters

The experiment was carried out to evaluate the effects of supplementing laying hen diets with different percentages of black tea factory waste (BTFW), evaluating performance, egg quality, yolk oxidation, and blood parameters. Twenty-four-week-old Lohmann layers (n=144) were divided into six dietary treatment groups (24 hens each), which were fed standard commercial diets supplemented with 0% (control), 2%, 4%, 6%, 8%, and 10% BTFW for 12 weeks. In this study, increasing BTFW levels were associated with impaired linearly feed consumption, final body weight, shell strength, shell weight, shell thickness, and increased cracked egg yield. The results showed a quadratic effect on albumen index, haugh unit score, and a cubic effect on feed conversion ratio, egg production, egg weight, yolk color due to the BTFW supplementation into layer diets. Whereas, shape index and yolk index were not affected by BTFW. In response to increasing BTFW percentage, yolk MDA values were decreased following storage for 14 and 28 days, but not 56 days. Plasma cholesterol, HDL, and aspartate aminotransferase (AST) were not influenced by BTFW. Increasing BTFW percentages led to linear increases in serum albumin and total protein, quadratic increases in triglyceride and alanine aminotransferase, and decreases in glucose (quadratic) and alkaline phosphatase (cubic). Results from present study showed that supplementing laying hen diets with 2% and 4% BTFW resulted in strong antioxidative activity without adverse effect on laying performance, quality characteristics, and blood parameters. In addition, more than 4% BTFW had deleterious effects on performance and egg quality traits, due to high tannic acid content.