Abstract:
A study was conducted to evaluate the effect of substituting different levels of sweet potato tuber meal (SWPTM) for maize on egg production, fertility, hatchability and egg and chick quality of white leghorn chicken at Poultry Farm of Haramaya University. A total of one hundred ninety two (168 hens + 24 cocks) at age of 42 weeks with initial body weight of 997.95g±19.2 (mean ±SD) were randomly distributed into 12 pens each with 14 hens and 2 cocks. The experimental animals in a pen were randomly allocated to one of the four treatments in a completely randomized design (CRD) and kept on a deep litter floor system. The ingredients used were maize grain, sun dried sweet potato tuber meal (SWPTM), noug seed cake, soybean meal, wheat short, limestone, di-calcium phosphate, methionine, lysine, vitamin premix and salt. The treatments were substituting SWPTM for maize at a percentage of 0% (T1, control), 9% (T2), 18% (T3) and 27% (T4) in layers ration. Daily Dry matter intake (93.8, 94.6, 93.9 and 95g for T1, T2, T3 and T4, respectively) was not statistically different (P>0.05) among the treatments. Daily mean body weight gain of hens fed T4 diet (2.5g) was significantly (P<0.05) higher than T2 (1.6g), T1 (1.28g) and T3 (1.2g). Percentage hen- day egg production (50.9, 55.7, 52.6, & 46.9, for T1, T2, T3 and T4, respectively) was significantly higher in T2 followed by T3 than T1 and was least T4. Hens fed T4 has significantly (P<0.05) lower egg mass (24.7g) than hens fed T1 (27.0g), T2 (29.6 g) and T3 (27.9g). Feed conversion efficiency (0.264, 0.29, 0.274, and 0.235 for T1, T2, T3 and T4, respectively) was in the order of T2>T3>T1 >T4. Roche color reading revealed that eggs from hens fed T4 (4.2) and T3 (4.1) have yellowish yolk color than T2 (3.9) and T1 (3.5). There were no significant differences (P>0.05) among treatments on egg weight, albumen quality, yolk diameter, yolk weight, yolk index, shell weight, egg shell thickness, albumen height, Haugh unit, fertility, hatchability, embryonic mortality, chick weight, chick length and chick visual score. The economic return analysis showed that substitution of maize with SWPTM (T2) at 9% returned higher profit followed by T3. Therefore, On the basis of the results of the present study, it was concluded that inclusion of 9% SWPTM for maize significantly improved egg production and total profit without any detrimental effect on the other parameters studied. On the other hand, highest levels of SWPTM improved body weight gain and yolk color
