No abstract

Day-old Lohman broiler chicks (n = 120) were fed on five starting diets for 4 weeks in groups of 24 birds. The starting diets contained 0%, 9%, 18%, 27% and 36% sweet potato tuber as a replacement for maize. From the fifth week, the 120 birds were tested in groups of 30 on four finishing diets containing 0%, 15%, 30% and 45% sweet potato tuber as a replacement for maize. The carcass quality was significantly (p < 0.05) improved due to a significant (p < 0.05) reduction of abdominal fat in the birds fed on the 45% sweet potato finisher diets. However, the birds on the sweet potato diet continually passed wet droppings, resulting in a significant (p < 0.05) reduction in body weight and feed conversion efficiency. The optimum levels of inclusion of sweet potato in the diets were considered to be 27% and 30% for starting and finishing broiler chickens, respectively. Sweet potato diets may be a remedy for fatty broilers.

Sixty weanling Large White x Duroc pigs were allocated to five groups of 12 pigs per group and fed on one of five diets. The five diets comprised 0, 50% and 100% unboiled, sun-dried taro cocoyam cormels (Colocasia esculenta) and 50% and 100% boiled, sun-dried taro cocoyam cormels as replacements for maize. The levels of some antinutritional factors were also determined in both boiled and unboiled, sun-dried taro cocoyam. Boiling reduced (p < 0.05) the amounts of the antinutritional factors in the taro cocoyam cormels. There were no significant differences (p > 0.05) in feed intake, weight gain or feed efficiency between the diets containing boiled taro cocoyam cormels. However, for unboiled, sun-dried taro cocoyam cormels, there were significant differences (p < 0.05) in weight gain and feed efficiency, these being depressed at more than 50% replacement of maize. This may be due to the relatively high amounts of antinutritional factors in the unboiled, sun-dried taro cormels. Boiled taro cocoyam cormels were comparable to maize as an energy source in the diets of weanling pigs.

No abstract

One hundred and twenty-six point-of-lay birds were randomly alloted into six groups of 21 birds each and fed six diets containing 0%, 10%, 20%, 30%, 40% or 50% of Dioscorea alata meal as a replacement for maize, corresponding to 0%, 20%, 40%, 60%, 80% and 100% maize replacement. There were no significant differences (p > 0.05) in feed intake, egg weight or feed efficiency between the control diet and the test diets. However, the daily egg production per 100 birds (hen day production), differed significantly (p < 0.05) among the treatments. The birds on the control diet and diets with substitution rates of up to 80% laid significantly (p < 0.05) more eggs than those on the 100% substitution rate. This shows that D. alata can replace up to 80% of maize or constitute 40% of a laying chicken diet, provided the rations are isocaloric and isonitrogenous. For this to be achieved, more soybean and/or more fish scraps, and more palm oil are needed in the diets containing D. alata than in diets based on maize.

Tannia cocoyam meals (CCYM) as substitutes for maize were evaluated in a six week feeding trial, in order to determine and compare effects of dietary inclusion at 100% of tannia cocoyam and the levels of antinutritional factors present. Ninety-six broiler chickens at four weeks of age were randomly allotted in groups of 12 to one of the following diets. The dietary treatments contain 0, 25, 50 and 100% CCYM of Tannia which comprised of raw sundried and boiled sundried forms. Proximate analyses of the test ingredient and that of maize was conducted. Antinutritional factor analyses of the test ingredients were also conducted. Carcass quality evaluation was also determined only on control groups and 100% (cocoyam inclusion). The results of proximate compositions indicated that tannia is higher in crude fibre, ash and nitrogen free extract. The weight of crop on raw tannia (31.70) was significantly lower (p<0.05) than that of the control diet (32.45). The live weight, dressed weight and eviscerated weight and all other cut parts for both raw and boiled CCYM were similar (p>0.05) to control. The weights of crop and intestine on 100% CCYM diets differed significantly (p<0.05) with lower values on the control (32.45 and 112.08 respectively) and higher values on boiled sundried tannia (53.74 and 132.30 respectively). Significantly higher levels (p<0.001) of anti-nutritional factors were observed on raw sundried tannia than the boiled sundried tannia. The carcass yield and organs weight were significantly higher (p<0.05) on boiled sundried tannia as compared to that of raw sundried. Thus, better feed utilization on boiled tannia diets due to higher feeding value than raw sundried cocoyam. Therefore, boiled tannia could replace maize at 100% inclusion levels without any adverse effects on carcass characteristics, but lower levels of raw tannia is recommended due to higher content of antinutritional factors.