The inclusion of dietary fiber (DF) in diets has been suggested as a way to reduce NH(3) emission in pig barns because it contributes to a shift in N excretion from urine to feces owing to enhanced bacterial growth in the intestines. This study compared an in vitro method to measure bacterial protein synthesis during fermentation with an in vivo N excretion shift induced by diets differing in DF concentrations and solubility. The first experiment measured the effect of graded concentrations of sugar beet pulp (SBP; 0, 10, 20, and 30%) in corn- and soybean meal-based diets on in vivo N excretion partitioning between the urine and feces. A second experiment investigated the replacement of SBP, rich in soluble DF, with oat hulls (OH), rich in insoluble DF (20:0, 10.5:10.5, and 0:22%, respectively). In parallel, the fermentation characteristics of the dietary carbohydrates not digested in the small intestine were evaluated in an in vitro gas test, based on their incubation with colonic microbiota, using a mineral buffer solution enriched with (15)N. The N originating from the buffer solution incorporated into the bacterial proteins (BNI) was measured when half the final gas volume was produced (8.5 to 14.5 h of fermentation) and after 72 h of fermentation. Short-chain fatty acids were determined in the liquid phase. In the first experiment, the inclusion of SBP linearly decreased urinary N excretion from 0.285 to 0.215 g of N excreted in the urine per gram of N ingested and decreased the urinary-N:fecal-N excretion ratio from 2.171 to 1.177 (P < 0.01). In the second experiment, substituting SBP with OH linearly increased the urinary-N:fecal-N excretion ratio (P = 0.009). Unlike short-chain fatty acid production, BNI was greater at half-time to asymptotic gas production than at 72 h of fermentation. Sugar beet pulp enhanced BNI linearly (P < 0.001), 2.01, 2.06, and 2.35 mg g(-1) of diet with 10, 20, and 30% SBP, respectively, as compared with 1.51 mg for the control diet. The substitution of SBP with OH decreased BNI (P < 0.01). With the exception of final gas production, all in vitro kinetic characteristics and BNI were correlated with in vivo N excretion parameters, and regression equations for the prediction of N excretion pathways from in vitro data were identified. Even if the presence of resistant starch in the diet might alter the composition of the fibrous residue that is fermented, the in vitro method is a possible useful tool for the formulation of diets, reducing the effects of pig production on the environment.

The study was carried out in Bensa district of Sidama zone, Southern Ethiopia. Agro-ecologically, the study sites were classified into highland and mid-altitude. The objective of the study was to identify sheep farming practices in relation to future production strategies in the study area. A total of 128 households from four kebeles (lower administrative structure) were selected purposively based on sheep population and production potential and accessibility. Data was collected through semi-structured questionnaire, focus group discussions, and key informants. The result showed that most of the household heads were male (92.75%) and mixed crop-livestock system was the dominant production system. Among the livestock species, sheep accounted for the largest proportion across the two agro ecologies and the average sheep flock size/household was 4.6 ± 0.33 and 22 4.3 ± 0.213 in highland and in mid-altitude, respectively. The primary reason of keeping sheep was for cash income and saving across the two agro ecologies. The major feed resources for sheep during the wet and dry seasons were natural pasture and crop residues respectively across the two agro ecologies. Feed shortages, disease, parasite prevalence, and market were the major sheep production constraints in highland while feed shortage, genotype, disease, parasite prevalence, and market in mid-altitude. It can be concluded that for enhancing future production from sheep in the area, emphasis is to be given on feed availability, disease management, breeding policy, and marketing strategies.