Abstract:
Green leafy vegetables like Moringa oleifera-MO, Ocimum gratissimum-OGand Vernonia amygdalina-VA are ubiquitous and contain bioactive compounds which may be used to improve quality indices of eggs. Golden yellow colour is an index of egg yolk that is most preferred by consumers and could be achieved by feeding leaf meals to laying hens instead of commercial yolk colourants. Previous researches on Dietary Leaf Meals (DLM) for hens were focused on performance and digestibility with scanty information on sensory attributes and quality of eggs. Therefore, quality characteristics of eggs from hens fed diets containing MO, OG and VA DLM were investigated.
Leaves of MO, OGandVA were harvested at week 20 of regrowth, air-dried, milled, sieved with 0.05 mm mesh and assayed for crude protein, ash and secondary metabolites using standard procedures. Four soybean-maize based diets were formulated: control T1 (0% DLM) while T2, T3 and T4 contained 2% MO, OG and VA, respectively. One-day old pullet chicks (n=240) were allotted to the diets. Control diet was fed to 24 chicks for 61 weeks while diets T2, T3 and T4 were fed to six chickens per replicate from: weeks 0-61 (Regime 1); 9-61 (Regime 2) and 18-61 (Regime 3) using completely randomised design. Each treatment was replicated four times. Egg Weight-EW (g), Yolk Weight-YW (g), Yolk Colour-YC (Roche yolk-fan scale: very light yellow 1-14 orange), Albumen Weight-AW (g) and Haugh Unit-HU (%) were determined at Mid Lay-ML (53-58 weeks) using standard procedures. Data were analysed using descriptive statistics and ANOVA at α0.05.
The MO, OG and VA leaves contained 19.6±0.0, 19.1±13.6 and 24.8±4.6% crude protein and; 3.8±1.7, 7.3±5.9 and 7.2±5.2% ash, respectively. Terpenoids, steroids and phenols were detected in the three DLM while only VA had saponins. The DLM type did not affect EW. Hens on regime 1 had significantly higher EW (58.3±5.3) than those on regime 2 (56.0±5.9) and regime 3 (57.2±5.6). Similar YW was observed in eggs from control(15.1±0.2) and OG (15.1±0.2) but higher than MO (14.9±0.2), while VA (15.5±0.3) was highest. Eggs from regime 1 had significantly higher YW of 15.4±2.3 thanregime 2 (15.1±3.1) which was also higher than regime 3 (14.8±2.2). Eggs of hens fed OG, VA and control diets had similar light yellow YC ratings (2.9±0.2, 3.0±0.2 and 2.9±0.1, respectively) but differed from MO (3.5±0.1, golden yellow).Feeding regime had no effect on YC. Albumen weight among DLM was similar but differed among regimes. Regime 1 had AW of 35.6±4.3,regime 2 and regime 3 had values of 33.7±5.2 and 34.6±4.6, respectively. Haugh unit of eggs was not affected by DLM while regime of feeding was significant. Eggs from Regime 1 had significantly higher HU (79.8±4.1) than Regime 2(278.8±5.4) and also higher than Regime 3 (77.8±5.5).
Dietary leaf meals used in this work improved egg weight of hens fed from one day old to week 61. Leaf meal inclusion resulted in healthier eggs with lower low density lipoprotein Moringa oleifera leaf meal enhanced golden yellow yolk colour of eggs.
