Jmk. Muia et al., Rumen degradation and estimation of microbial protein yield and intestinaldigestion of napier grass (Pennisetum purpureum) and various concentrates, ANIM FEED S, 93(3-4), 2001, pp. 177-192
A study was conducted in a repeated measure arrangement using four rumen fi
stulated steers to determine degradation of napier grass (Pennisetum purpur
eum), protein ingredients and concentrates. Cotton seed cake (CSC), poultry
litter (PL), soyabean meal (SBM), and sunflower seed meal (SFM) were used
in Trial 1. In Trial 2, a commercial concentrate, a PL-based concentrate, a
SFM-based concentrate and two napier grass cuts; medium (MNG) and old (ONG
) were used. Rumen degradation data was used to estimate yields of rumen mi
crobial protein (RMP) and total protein digestion in the intestines (TPDI).
The estimated yields of RMP and TPDI values were comparable to determined
values in other studies. The protein ingredients had highest (37-88 g N kg(
-1) fermentable organic matter (FOM)), concentrates moderate (26-27 g N kg(
-1) FOM) and napier grass lowest (10-19 g N kg(-1) FOM) efficiency of RMP s
ynthesis. The yields of RMP (44-52 g kg(-1) DM) and TPDI (49-79 g kg(-1) DM
) were lower in ONG than MNG (P < 0.05). Among the protein ingredients, yie
lds of RMP (58-87 g kg(-1) DM) and TPDI (89-219 g kg(-1) DM) were lowest in
PL and highest in SBM (P < 0.05). Among the concentrates, the PL-based con
centrate had the lowest while the commercial concentrate had the highest yi
elds of RMP (75-84 g kg(-1) DM) and TPDI (96-118 g kg(-1) DM) (P < 0.05). S
upplementing animals with CSC, SBM, and SFM would support high performance
while moderate levels of production would be obtained from commercial conce
ntrate or SFM-based concentrate. Supplementing animals with PL or PL-based
concentrate would, however, result in low levels of production. To sustain
same levels of production, animals fed ONG should be offered supplements co
ntaining about 30 g kg(-1) DM more TPDI than animals fed MNG. (C) 2001 Else
vier Science B.V All rights reserved.