IN-SITU AND IN-VITRO RUMINAL STARCH DEGRADATION OF UNTREATED AND FORMALDEHYDE-TREATED WHEAT AND MAIZE

Ruminal starch degradation of untreated and formaldehyde-treated wheat and maize was measured in situ (trial 1) and in vitro (trial 2). The in situ starch degradability was higher for wheat than for maize (82.1 vs 52.3%), for untreated cereals than for cereals treated with 1% for maldehyde (77.3 vs 67.0%) and for cereals treated with 1% formaldehyde than those treated with 5% formaldehyde (67.0 vs 57.2%). The in vitro results were similar. The treatment of cereals by formaldehyde decrea sed starch degradability more for wheat than for maize, suggesting tha t the treatment was more efficient when cereal starch and/or nitrogen was highly degradable. Formadehyde treatment of wheat was more effecti ve at decreasing the rate of wheat protein degradability than starch d egradability. The difference of response to treatment between the two cereals may be due to differences in properties of the protein matrix of these two cereals.