Genotype and ginger (Zingibar officinale) rhizome powder dietary supplementation affect egg quality indices of aged layer chickens

Abstract

The study evaluated the effect of genotype and dietary ginger supplementation on egg qualities of aged Shaver brown (SB) and Nigerian heavy ecotype native (HEN) hens. Control (basal diet) groups received layer ration while supplemented (ginger diet) groups received 20g ginger/kg basal ration. Hens were fed 125g/bird/day of the experimental rations. Water was given ad libitum. 80 and 40 eggs were collected from SB and HEN basal diet groups, respectively while 80 eggs/genotype were collected from the ginger diet groups for determination of egg qualities. Egg, yolk, albumen and shell weights (EW, YW, AW and SW); egg length (EL), surface area (ESA), volume (EV), specific gravity (ESG) and shape index (ESI); egg, yolk and albumen diameters (ED, YD and AD); yolk and albumen heights (YH and AH); yolk, albumen, and ratios (YR, AR, SR) and indexes (YI, AI and SI); yolk:albumen (Y/A), Haugh unit (HU); and shell thickness (ST), volume (SV), density (SD) and compression fracture force (SCFF) were determined. Within genotypes, eggs were graded by weight and shape index and compared for quality indices. Main and interaction effects were evaluated by Two-way Analysis of Variance (ANOVA). Shape index grades in SB and weight grades in SB and HEN were compared by One-way ANOVA while shape index grades in HEN were compared by the Student’s T-test. Significant differences were accepted at p ≤ 0.05. Eggs from SB had higher EW, EL, ED, ESA, EV, ESI, YW, AW, AH, AD, AR, SW, SV, SCFF, HU, and Ca but lower ESG, YR, Y/A, Zn and P than HEN eggs. Within genotypes, ginger groups had higher EW, EL, ESA, EV, YW, YD, YR, AH, AI, Y/A, and Zn, but lower ESG, YH and YI compared to basal diet groups. Genotype x diet affected AD (SB-ginger group ˃ basal diet groups ˃ HEN-ginger group), Zn (HEN-ginger group ˃ SB-ginger group ˃ basal diet groups), and P (HEN-ginger group ˃ HEN-basal diet group ˃ SB-diet groups). Egg weight grades differed significantly in EW, ESA, ESG, ESI and SCFF in SB and HEN while shape index grades differed significantly in ESI and Y/A in SB but in ESI, YI and HU in HEN. Overall, genotype, diet, genotype x diet, and weight and shape grades influenced some of the egg quality traits.