Metabolizable energy and amino acid digestibility of decorticated extruded safflower meal.

An experiment was conducted to determine TME and amino acid digestibility of several dehulled extruded safflower meals. Finely ground partially dehulled extruded (ESM), partially dehulled solvent-extracted (SESM), extensively cleaned dehulled and extruded safflower meal (CSM), or soybean meal 44 (SBM 44) was intubated to 9 fasted mature roosters with 40 g per rooster and total excreta was collected.The concentrations of all essential amino acids in CSM were higher than those in ESM and SESM. Also, compared with SBM 44, CSM was deficient in lysine, slightly higher in TSAA and tryptophan, but much higher in arginine. The AME(n) and TME(n) of CSM were 2,413 and 2,832 kcal/kg, respectively, and were higher than those of SBM 44 (P < 0.01). The true lysine digestibilities of CSM and SBM 44 were similar but were higher than those of ESM and SESM (P < 0.05). However, ESM, SESM, and CSM had similar true tryptophan and threonine digestibilities that were lower than that of SBM 44 (P < 0.05). With respect to TSAA, all feed ingredients under investigation had similar apparent and true digestibilities. In conclusion, extensive hull removal of safflower seeds followed by cold extrusion produced a low-fiber CSM rich in both energy and protein that makes it a promising feed ingredient for poultry.

Effects of underfeeding and refeeding on offals weight in the Barbary ewes.

The influence of long-term (161 days) underfeeding and refeeding (154 days) on the weight of offal components, and digestive content, was studied in 26 adult Barbary ewes. Effects on the protein and mineral content of offals were also measured. Animals were split in three groups: one was fed hay at maintenance level (M), another also received vetch-oat hay to cover 0.2 of maintenance energy requirements (L), and the third one was fed at 0.2 of maintenance requirements during 161 days, then refed at 1.3 times of energy requirements with a diet of hay and barley grain (LH) during 154 days. Underfed animals body weight (BW) at slaughter was 31kg. Animals of groups M and LH were slaughtered at similar BW (50kg). Underfeeding reduced empty BW by 38% and the weight of most metabolically active organs: skin (40%), blood (31%), rumen (34%) and liver (19%), but not others (small intestine). Total offals weight was reduced by 27%. Overfeeding of previously underfed animals (LH) induced a significant increase in liver weight in comparison to M group (18%), owing to a higher nutrient supply. The amount of protein in offals and their fat-free weight were decreased by underfeeding, whereas the amount of minerals was significantly modified only in components rich in bone. These results showed that splanchnic organ mass decreases with underfeeding which leads to energy requirements decrease and contributes towards resistance of Barbary ewes to harsh food conditions.

Effect of defaunation on protein and fibre digestion in sheep fed on ammonia-treated straw-based diets with or without maize.

Using a defaunating method which preserved bacteria and fungi in the rumen, the effect of protozoa on protein and fibre digestion was studied in six adult wethers in relation to the nature of the diet. Sheep were given daily, 42 g dry matter (DM)/kg metabolic body-weight (W0.75), one of two isonitrogenous diets: one contained ammonia-treated wheat straw as the only energy source (diet S) and the other was supplemented with maize grain pellets (diet SM). Mean daily intakes (g/d) of nitrogen, neutral-detergent fibre and acid-detergent fibre were respectively 22, 573 and 373 for diet S and 23, 450 and 334 for diet SM. Elimination of protozoa increased duodenal non-ammonia-nitrogen flow. This result was mainly due to an increase in microbial protein flow and, to a lesser extent, to a higher dietary protein flow. Defaunation markedly increased the efficiency of microbial protein synthesis. Maize-grain supplementation had a net positive effect on this variable in defaunated sheep, but not in faunated sheep. Cell-wall carbohydrates were less well digested in the defaunated rumen, and the negative effect of defaunation was greatest with the diet SM. Intestinal fibre digestion increased in the defaunated sheep especially in those fed on diet SM, but not enough to compensate for the decrease in rumen digestion.

Effect of defaunation and refaunation of the rumen on rumen fermentation and N-flow in the duodenum of sheep.

In order to confirm earlier fragmentary results, the effect of defaunation and refaunation of the rumen on the fermentation pattern and flow of N-components in the proximal duodenum of two sheep was investigated. Defaunation had no effect on acetic acid as a proportion of the total volatile fatty acids in the rumen, while the proportions of propionic acid increased with a concomitant decrease in butyrate. Refaunation resulted in lower acetic acid and higher butyric acid proportions. The concentration of ammonia N in the rumen was clearly decreased after defaunation, already indicating an effect of the elimination of protozoa on nitrogen metabolism in the rumen. Defaunation also increased significantly the flow of total N, non ammonia N and individual and total amino acids in the proximal duodenum. Defaunation resulted in higher bacterial growth efficiency, significantly in one sheep, but the decrease after refaunation was statistically significant for both sheep. Determination of rumen digestibility of organic matter and acid detergent fibre (ADF) revealed lower values in the absence of the protozoa, while total digestibility was only influenced to a much lower extent. This indicated a shift of digestion from rumen to the lower digestive tract. Finally, earlier work is discussed in the light of the present findings.