Effect of replacing groundnut seed cake with a brewer’s yeast–noug seed cake mixture in ration on egg quality, fertility and hatchability of White Leghorn chickens

The high cost and limited availability of conventional protein feed ingredients have increased the need for alternative protein sources in poultry diets. Therefore, this study evaluated the effect of replacing groundnut seed cake with a brewer’s yeast–noug seed cake (BYNSC) mixture on egg quality, fertility, and hatchability of White Leghorn laying hens. A total of 180 White Leghorn laying hens (28 weeks old) and 30 cocks were assigned to a completely randomized design with five dietary treatments and three replicates. Brewer’s yeast–noug seed cake mixture progressively replaced groundnut cake with five dietary treatments containing increasing levels of the BYNSC. Egg quality, fertility, and hatchability were evaluated, and data were analyzed using the General Linear Model procedure in SAS. The BYNSC mixture had favorable crude protein and metabolizable energy content. Egg shape index showed a significant overall treatment effect and a significant quadratic dose-response trend ( P < 0.05); however, Tukey’s pairwise comparisons did not detect significant differences between individual treatments. The BYNSC mixture did not significantly affect egg weight, eggshell, most egg yolk, and albumen quality traits ( P > 0.05). But yolk colour was significantly affected ( P < 0.05) with T2 (4.41) showing a significantly highest score. Fertility and hatchability did not differ significantly among the treatments ( P > 0.05). Overall, feeding the BYNSC replacement diets did not negatively affect most egg quality, fertility, or hatchability traits. Feed intake exhibited a complex curvilinear response (linear, quadratic, cubic, and quartic trends; P < 0.05), with the highest intake recorded at the 50% replacement level (T3). Future studies should be undertaken on the drying process of liquid spent brewer’s yeast and evaluation of the amino acid profile of sun-dried spent brewer’s yeast alone and in blended form.