P. Laurinen et al., EFFECTS OF DIFFERENT EXPANDER PROCESSING CONDITIONS ON THE NUTRITIVE-VALUE OF BARLEY AND WHEAT BY-PRODUCTS IN PIG DIETS, Animal feed science and technology, 74(3), 1998, pp. 213-227
The apparent nutrient digestibility and nitrogen (N) utilization was s
tudied to evaluate the responses of growing pigs (from 31 to 70 kg) fo
r the expanding of barley and wheat bran-wheat middlings mixture (2:1)
(WEM). In Experiment 1, four male castrates were used in a 4 x 4 Lati
n square where the effects of expanding (unexpanded vs, expanded) and
WBM level (200 vs. 400 g/kg) were studied. In Experiment 2, five male
castrates were used in a 5 x 5 Latin square where effects of steam add
itions during processing were studied and WBM diets were compared to a
barley-soybean diet (barley-SB diet) (WBM 300 vs. 0 g/kg). WBM and ha
mmer milled barley were expanded separately by adding 0.0, 3.0 and 6.0
% (w/w) steam into the expander. WBM was included in barley-SB meal di
ets by formulating to the same crude protein content (163 g/kg). The e
ffects of expanding on digestibility were very small excluding that of
ether extract which improved remarkably. The calculated digestibiliti
es (%) of dry matter, NDF-fibre, ether extract and crude protein in th
e WBM were 72.0, 44.0, 39.3 and 81.2 (standard error 1.8, 4.4, 5.9 and
5.8) and in the expanded WBM 69.9, 44.7, 58.3 and 78.3 (standard erro
r 2.8, 4.7, 5.8 and 6.8), respectively. The nitrogen retention (N rete
ntion) remained the same in experiment 1, but expanding improved that
in experiment 2, The steam addition during expanding improved linearly
digestibility of ether extract, while digestibility of the other nutr
ients and N balance were unaffected. The increased WBM level from 200
to 400 g/kg depressed digestibility of dry matter, organic matter, cru
de carbohydrates and gross energy without affecting the N retention. N
itrogen retention and digestibilities of all nutrients excluding ether
extract and ADF-fibre in the barley-SE diet were superior to those of
the WBM diets. Expanding increased undigestible dietary N (UDN) excre
tion and decreased the percentage of bacterial and intestinal debris N
of faecal N. WBM increased UDN excretion. The other effects of expand
ing and WBM level on faecal N fractions were contradictory between our
experiments. (C) 1998 Elsevier Science B.V.