Energy metabolisability and digestibility of amino acids by broilers fed on malted sorghum sprouts supplemented with polyethylene glycol, charcoal, phytase and xylanase

A precision feeding study was conducted to determine the metabolisable energy and amino acid digestibility in broilers fed on malted sorghum sprouts (MSP) supplemented with polyethylene glycol (PEG), charcoal (CH), phytase and xylanase. A total of 64 male Ross broilers housed individually (8 replicates per treatment) were fed 30 g of the feedstuff as follows by gavage: MSP, MSP + 1 g PEG/kg, MSP + 10 g PEG/kg, MSP + 1 g CH/kg, MSP + 10 g CH/kg, MSP + 3600 IU of evolved E. coli phytase/kg (EC 3.1.3.26) and MSP + 1600 IU of bacterial xylanase/kg (EC 3.2.1.8). Another group of birds was used for the assessment of endogenous loss and they were provided with 50 ml glucose solution each by gavage. True dry matter digestibility (TDMD), true nitrogen retention (TNR), total tract digestibility of apparent and true metabolisable energy (AME and TME) and amino acid (AAD and TAAD) were determined. MSP contained 244 4, 24.0, 74.9 and 224.0 g/kg of crude protein, ether extract, ash and neutral detergent fibre, respectively. The total tannin content of the product was 140 g/kg and 99% of this was bound. The various dietary treatments did not significantly affect the TDMD, TNR, AME and TME of MSP. The low values (0.471 g/g, -0.164 g/g, 6.15 MJ/kg and 9.31 MJ/kg, respectively) for the above measurements depicted the low feeding value of un-supplemented MSP for poultry. Also, PEG, CH and enzymes did not improve the AAD and TAAD of MSP for poultry. It was concluded that the tannin content of MSP is high and it appeared to be bound with other nutrients thereby reducing their availability. This may explain its low AME and amino acid digestibility and the lack of effect of the various treatments for poultry. © 2007 British Poultry Science Ltd.