Prof Richard DUCATELLE (Ghent Univ., Belgium)
What about using some types of insoluble fibers instead of wheat bran? About the effect in both bird health and beneficial bacteria?
The studies we did in wheat bran were focused on particle size. The wheat bran is a source of insoluble fiber containing mostly arabinoxylans but also several macromolecules of a different chemical nature, such as beta-glucans and cellulose. We also investigated some of these as purified insoluble fibers, such as cellulose. It turned out that (amorphous) cellulose could have a beneficial effect as well, but through a completely different mechanism. Beneficial effects can also be obtained by adding xylanases, which break down the arabinoxylans into oligomers. The mode of action of the xylanases is similar to that of the particle reduction of the wheat bran.
What would happen by using the same particle size of another feedstuff?
That we have not tested. However, Dr. Steven Ricke has tested wheat bran of different particle sizes. He could show a beneficial effect. However, he additionally showed that the effect clearly different depending on the rice variety. In our studies we have not compared different varieties of wheat.
Prof Peter SURAI (Feed-Food Ltd, Glasgow, UK)
How can use MDA analyses in liver as indication about bird stress . What is the normal level?
Increased level of MDA in the liver would indicate that the antioxidant system was not capable to completely prevent oxidative stress and some lipids were oxidised. As for normal levels, they would depend on bird age, nutrition amd many other parameters/factors including differences in analytical techniques of MDA assay (photometric, HPLC, etc.). Therefore, there are no generally accepted MDA levels which would indicate the level of bird’s stress. However, it is possible to establish physiological and pathological levels of MDA at each poultry farm by using standardised technique as well as physiological conditions with high productive and reproductive performances of birds and pathological levels in some stress conditions, including heat stress.