Evaluation of Magadi soda-treated sorghum grain for young broilers

Magadi soda (MS) is a commercially available form of sodium sesquicarbonate in Kenya. Soaking high-tannin sorghum (HTS) grain (2.5% catechin equivalents) in a 6 g l−1 MS solution was shown to eliminate measurable tannin content. A feeding trial was conducted to investigate the performance of broiler chicks fed soyabean-based diets containing HTS or MS-treated HTS as the sole cereal source from 1–3 weeks of age. A third diet containing sorghum with no detectable tannin content served as the control. Diets containing 220 g kg−1 crude protein were fed to 6 pens of 5 birds per pen for each treatment from 1–2 weeks of age and to 4 pens of 4 birds per pen per treatment in weeks 2–3. Feed intake, weight gain and feed efficiency (FE) were determined weekly. Apparent dry matter digestibility (DMD), metabolizable energy (AMEn) and nitrogen retention (NR) were measured over the last 3 days of each period. Gain and feed intake were not affected by treatment (P>0.05), but FE and DMD were lower (P<0.05) for the HTS diet than for the MS-treated HTS and control diets, which themselves were similar. Absolute NR was higher (P<0.05) for the control diet than either of the HTS diets in week 2 but was the same for all diets in week 3. As % of intake, NR was higher (P<0.05) for the control in both weeks 2 and 3 than for the HTS diets, although this was improved (P<0.05) by MS treatment in week 2. AMEn values showed a similar pattern to that for NR in week 2 but in week 3 was the same for the MS-treated HTS and control diets, which were higher than the HTS diet (P<0.05). Though total tannin content did not influence growth of birds in this study, MS treatment of HTS did reduce deleterious effects on FE, AMEn and NR as a % of intake.