EFFECT OF DIETARY MAIZE SUBSTITUTION WITH SWEET POTATO MEAL ON PERFORMANCE OF LAYERS

Abstract

Two experiments were conducted with two sets of layers to determine the suitability of SPM in layers diet and monitor its effect on birds' performance at different stages of laying period. One hundred and eighty 22-week or 35-week old Shika Brown layers were used for the two experiments. In each experiment, the birds were weighed in equal groups of 12 and randomly distributed over 15 pens after which they were placed on 5 dietary treatments consisting graded levels of sweet potato meal (SPM). Each treatment consisting of 0, 10, 20, 30 and 40% SPM was replicated 3 times. Diets were iso-nitrogenous for each experiment. The differences in the two experiments lie in the energy and protein contents of the control diets. The experimental setup was a complete randomized design (CRD). Parameters measured and calculated include feed intake, body weight gain, final body weight, feed conversion ratio, mortality, hen- day egg production, cumulative egg production, yolk index, Haugh unit, shell thickness and egg weight. The experiment lasted for 12 and 18 weeks respectively. The result did not show significant effect on final body weight of birds, egg weight, feed conversion, haugh unit, yolk index, shell thickness and mortality. However, cumulative weight, cumulative egg production and hen-day egg production decreased linearly (P<0.05) with increase in dietary SPM, while feed intake, feed intake/egg, feed conversion ratio and feed cost/egg increased. In all cases except cumulative weight gain, similar results were produced by the control, 10, 20 and 30% SPM diets while the 40% SPM diet proved significantly inferior (P<0.05). Similar weight gains were recorded for birds on control, 10 and 20% SPM, while the weight gains of birds on 30 and 40% SPM diets were significantly lower. The performance indices thus showed that SPM should not be incorporated beyond 30% level for layers.