ABSTRACT
This study aimed to assess the effect of natural antioxidants on storage time, physical and chemical properties of egg. A total of 200 laying ISA brown birds were distributed into eight dietary groups, each dietary group with 25 birds (5 birds per replicate). They were fed with roselle, black pepper, green tea, combine (roselle + black pepper + green tea) at 0.5 g/kg and 1.0 g/kg in basal diet respectively and a control feed. At the end of eight (8) weeks of feeding trial, twelve eggs were collected from each dietary group (six eggs per dietary group were analyzed for the internal and external properties while the remaining six were stored). Data collected include; Egg shape index, egg weight, shell thickness, membrane weight, yolk index, haugh unit, meat and blood spot, yolk colour, lipid profile, lipid peroxidation and proximate analysis. Data generated were subjected to Analysis of variance using the General Linear Model for factorial within a completely randomized design. The natural antioxidants significantly (P<0.05) improves the proximate composition of the poultry eggs. Both Green tea and Black pepper have significant effect (P<0.05) on the yolk percentage. Black pepper increases (P<0.05) the Haugh unit while it shows to be lower (P>0.05) in the combination of the antioxidants. The inclusion levels of the natural antioxidants on the internal and external quality of egg reveals that there were no significant (P>0.05) differences in the two inclusion level of 0.5 g/kg and 1.0 g/kg of feed but they have numerically higher values in the external parameters and internal parameters. Eggs stored for 4 weeks had the lowest value (P>0.05) for the proximate and lipid profiles, though there are no significant (P>0.05) differences in their values. The fresh eggs show high moisture content (P<0.05) but the value for nitrogen free extract is low (P>0.05) in the fresh eggs. The natural antioxidants improved significantly (P<0.05) the proximate composition of the poultry eggs, with the green tea having the highest value (P<0.05) for Moisture contents and CP, black pepper the highest (P<0.05) for CP Based on the result obtained from this study, the natural antioxidants (black pepper, green tea and roselle) in layers� diet shows significant effects on the physical qualities of egg and the yolk color was also preferred with the inclusion of the natural antioxidants compared to the control. The chemical properties also deteriorate with the storage time. Natural antioxidants are hereby recommended for better and improved chemical qualities of eggs.