The apparent metabolizable energy and feeding value of quality protein maize for broiler chicken.

摘要

Two experiments were undertaken to determine whether the quality protein maize (QPM) has any unexpected effects on poultry as a result of compositional changes in the grain that may have altered its nutritional value. In first experiment, the apparent metabolizable energy (AME) of QPM was estimated and compared with commercial maize (CM) in adult cockerels following traditional diet substitution method of total excreta collection at two substitution levels (20 and 40% of reference diet) of QPM and CM. The second experiment was conducted to compare the feeding value of QPM with CM in day old broiler chicken for six weeks. A standard control broiler ration comprising of commercial maize and soyabean meal was prepared. Two more test diets were prepared by substituting CM with QPM at 75 and 100% levels (w/w). All the diets were isocaloric and isonitrogenous and had same levels of lysine and tryptophan by adjusting the level of soyabean meal in the experimental diets. Unsexed, day-old broiler chicks (n=120) were randomly distributed into 12 groups of 10 chicks each. Each dietary group was replicated four times with ten chicks in each replication. The commercial and quality protein maize samples employed in this study were analyzed to contain dry matter - 89.79 and 88.87% and crude protein - 8.97 and 8.67%, respectively. The lysine content of QPM was 0.33%, which was about 57% higher than commercial maize (0.21%). The results of energy bioassay revealed that the apparent metabolizable energy (AME) values of CM and QPM were fairly similar at 3171+or-77 and 3185+or-59 kcal/kg, respectively. The growth performance of broiler chicks fed diets containing commercial or quality maize with respect to body weight gain, feed intake, feed conversion efficiency, and protein and energy utilization efficiency did not differ statistically (P>0.05) either at starting (0-3 wk), finishing (3-6 wk) or overall (0-6 weeks) growth phases. Various carcass traits (% of live weight) of broilers i.e., feather loss, blood loss, eviscerated and meat yield and yield of heart, gizzard and liver were also similar (P>0.05) in different dietary treatments. No statistical differences were observed in abdominal fat content and the yield of major cut up parts of the broilers reared under different dietary groups. The study envisaged that the apparent metabolizable energy (AME) values of CM and QPM were fairly similar and the feeding value of QPM was also comparable to CM for broiler chicken and could be substituted up to 100% level for commercial maize in maize-soybean meal based diet up to 0-6 weeks of age.