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Physio-Chemical and Nutritional Composition of Sorghum (Sorghum bicolor) as Potential Food and Feed for Humans and Poultry
Sorghum is the fifth most important grain crop after wheat, rice, maize and barley. Sorghum is cultivated for food and beverages for humans, and for feed and fodder for animals in America, Asia, Australia and Africa. Physical characteristics, proximate composition, total phenols and antioxidant activity, mineral content and amino acid profile of sorghum (Sorghum bicolor (L.) Moench) were studied. Forty-eight (±2.5kg) adult male broiler chickens were allocated to a complete randomized design with four sorghum diets to determine amino acid digestibility and metabolisable energy. Twelve (12) birds per diet were starved for 24h before receiving feed allowance of 50g. Thousand-kernel weights ranged from 33-28g with brown visual colour and texture that is somewhat corneous to floury. The sorghum grains were higher (P<0.05) in total phenolic and condensed tannins contents for varieties NS5511 and PAN8625. The antioxidant activity of sorghum varieties PAN8816 and PAN8609 were higher (P<0.05) than varieties NS5511 and PAN8625. CP content of varieties PAN8609 (9.54%) and PAN8625 (9.53%) were higher (P<0.05) than those of NS5511 (8.12%) and PAN8816 (8.45%). Starch (%) and GE (MJ/kg) contents differed among sorghum varieties. Mg (mg/kg) content was significantly higher (P<0.05) for variety PAN8625 than that of NS5511. P and Zn (mg/kg) contents of sorghum variety PAN8609 were higher (P<0.05) than those PAN8625, NS5511 and PAN8816. Similarly, PAN8625 had higher (P<0.05) P and Zn contents than those of varieties NS5511 and PAN8816. Thr, leu, phe, val, pro and ala contents of varieties PAN8625 and PAN8609 were (P<0.05) higher than those of NS5511 and PAN8816 which had similar (P>0.05) contents. Sorghum variety NS5511 had low amino acid digestibility values for arg, his, phe, thr and try. Apparent metabolisable energy corrected for nitrogen (AMEn) was the highest (P<0.05) for variety PAN8816 followed by variety PAN8609 with lowest value for NS5511. True metabolisable energy corrected for nitrogen (TMEn) values were similar (P>0.05) for varieties PAN8816 and PAN8609 and low in NS5511.
Keywords: sorghum, total phenols, antioxidant activity, amino acid profile, minerals