R. Hadorn et C. Wenk, EFFECT OF DIFFERENT SOURCES OF DIETARY FI BER ON NUTRIENT AND ENERGY-UTILIZATION IN BROILERS .2. ENERGY AND N-BALANCE AS WELL AS WHOLE-BODYCOMPOSITION, Archiv fur Geflugelkunde, 60(1), 1996, pp. 22-29
Various sources of dietary fibre (millet and soybean hulls) as well as
wheat starch were investigated for their influence on nutrient and en
ergy utilization in broilers. Twenty percent of the control diet (KO)
were either replaced with wheat starch (20% STA), millet hulls (20% HI
) or soybean hulls (20% SO). In two consecutive series of experiments,
the experimental diets were led ad libitum to 192 male chickens of Ro
ss hybrid (8 birds per cage) from day 8 to day 42. At the end of the t
rial, whole body composition was determined. Due to the highest energy
losses by excreta and a slightly increased heat production, the lowes
t energy balance (529 kJ/kg LW(3/4)) was seen with diet 20% SO. Higher
energy balances resulted with diet 20% STA (631 kJ/kg LW(3/4)) und 20
% HI (642 kJ/kg LW(3/4)). Values from 0.654 to 0.726 were estimated fo
r the transformation of metabolizable energy into retained energy. The
high energy balance of diet 20% HI could be due to interactions betwe
en the indicator content of the diet (HCl-insoluble ash) and the high
silicium content of millet hulls. This could also be observed in N uti
lization. N intake depended on feed intake and the crude protein conte
nt of the diet. In comparison to the control, N losses by excreta of 2
0% SO birds were increased br 30%. Addition of hulls led to an improve
d N-balance 5-9%). In all diets, highest N-balances per kg LW(3/4) res
ulted in week 3 and decreased up to week 6. Large variations occured i
n ht retention. No fibre related influence could be seen in nutrient c
ontent of whale bodies. Wheat starch addition mas followed br an incre
ase in fat (7%) and energy (5%) content, whereas the other nutrients w
ere diluted. Nutrient composition of the whole body depended significa
ntly on the energy:protein ratio of the diet. In comparison to whole b
ody composition, N and energy deposition were overestimated by the bal
ance method by about 20%.