Search

Supplementation of post-weaning diets with exogenous enzymes has been suggested to control post-weaning syndrome, by compensating for the under-developed endogenous enzyme secretory capacity and increasing nutrient digestibility in newly weaned pigs. The effect of in-feed enzymes in improving gut maturation, growth and/or health in weaned piglets is not always consistent. A systematic review and a meta-analysis were therefore conducted to determine which exogenous enzymes are most consistent in improving piglet growth and digestibility when supplemented to post-weaning diets. The mean difference effect of enzyme supplementation on growth and digestibility of dry matter (DM), gross energy (GE), crude protein (CP), and P digestibility was calculated for each study and this was used as the effect size estimate in the meta-analysis. The impact of feed enzyme supplementation on intestinal health and bone mineralization was also discussed where information was available in the literature. From a total of 90 studies included in the meta-analysis, gain to feed ratio (G:F) was improved in 55, remained un-changed in 28 and deteriorated in 7, in response to enzyme supplementation. Average daily gain, average daily feed intake and G:F was improved when phytase was supplemented in the diet. Phosphorous digestibility was increased with phytase supplementation while GE digestibility was reduced. Dietary phytase supplementation increased bone mineralization in pigs fed diets with a reduced P content. Supplementation with multi-enzyme complexes increased DM and CP digestibility. In conclusion, the most consistent improvements in piglet growth, P digestibility and bone mineralization were found due to exogenous phytase supplementation. Supplementation with xylanase alone or in combination with β-glucanase had inconsistent effects on piglet growth and nutrient digestibility. The most consistent improvements in growth and nutrient digestibility due to supplementation with multi-enzyme complexes were found when mannanase and/or protease were included in the complex.

The experiment was conducted on double-muscled Belgian Blue bulls, fitted with rumen, duodenal and ileal cannulas, according to a 5 × 5 Latin square design with one missing animal. All diets contained 320 g/kg of lupin seed (Lupinus albus, var. Lublanc) on a dry matter (DM) basis. Four grinding treatments of raw lupins (RAW) were used to obtain median particle sizes of approximately 0.5, 2.0, 4.2 or 6.0 mm. One extrusion treatment (EXTR) was also used and consisted of heating to 180 °C for 30 s. The pH and ammonia nitrogen (NH3–N) concentration kinetics in the rumen liquid differed between RAW and EXTR. The latter induced larger variation in these parameters after the meal. Quadratic effects of the grinding level on rumen fermentation parameters were observed at several sampling times for RAW. The grinding level had also quadratic effects on the intestinal digestibility of DM, organic matter (OM) and N, reaching a maximum with treatment 4.2 mm. The treatment 0.5 mm tended to reduce the microbial N flow at the duodenum whereas EXTR tended to increase the non NH3–N flow. The total digestible flow of N tended to increase with the intermediate grinding levels and EXTR. Lupin protein degradability was calculated at 0.78, 0.74, 0.65, 0.82 and 0.70 for the 0.5, 2.0, 4.2, 6.0 mm treatments and EXTR, respectively. Treatments 2.0 and 4.2 mm increased the digestible protein in the small intestine (DVE) content by more than 40% compared with treatment 0.5 mm. The balance between rumen fermentable N and energy (OEB) was reduced by 15% with the 4.2 mm and EXTR. Compared with treatment 4.2 mm, EXTR did not greatly improve the nutritional value of lupin seed. The results suggested that lupin seed should be coarsely ground or flattened to obtain a mean particle size between 2.0 and 4.2 mm for cattle feed, but that an insufficient grinding level (treatment 6.0 mm) induced a higher degradability of lupin protein, probably due to more intense rumination. Under our experimental conditions, the extrusion did not sufficiently improve the nutritional value of the seed to be economically viable. These results show that feeding standards should consider the influence of the grinding level of legume seeds in order to assess their nutritional value accurately.

The objective of this study was to examine the effect of microbial contamination of the incubation residue on the in situ nitrogen degradability of Italian ryegrass. Microbial nitrogen in the bag residues was estimated by the feed 15N dilution procedure, and the incorporation of feed 15N into the adherent bacteria was assessed after isolating a bacterial pellet and determining its 15N enrichment. Isotopically labelled Italian ryegrass (fertilized with 15NH415NO3) was harvested either in spring (early cut) or in summer (late cut). Forages were incubated in the rumen of two steers for 6, 24 and 48 h. The proportion of microbial N per unit of total N in the bag residue increased with incubation time, ranging from 184 to 853 mg microbial N/g total N at 6 and 48 h, respectively. 15N enrichment in the bacterial pellet was highest after 6 h of incubation (3.6 mg 15N/g N) and then declined steadily (0.8 mg 15N/g N in 48-h residues). Microbial 15N represented up to 0.422 g/g total 15N in the bag residue, but the incorporation of feed 15N into bacterial N did not account for more than 57 mg/g 15N incubated, this incorporation rate decreasing progressively with incubation time. Correction of apparent N disappearance for microbial N resulted in higher values of N degradability, especially for the late cut grass. A further correction considering the amount of microbial 15N had little effect on the estimation of corrected N degradability values. Therefore, some of the feed 15N is incorporated into bacterial N, but this fraction has a minor effect on the estimation of total microbial N in the bag residue by the feed 15N dilution approach, and hence on the estimation of corrected degradability values.

The effect of multinutrient block supply and polyethylene glycol 4000 (PEG) on intake, digestion and rumen fermentation was studied in sheep fed with air-dried Acacia cyanophylla foliage (acacia)-based diet. In Experiment I, six Noire de Thibar breed sheep ( BW =46 kg ) were used in double 3×3 Latin square design. All diets included about 360 g of dry matter (DM) of oat–vetch hay and acacia ad libitum. Diet D0 was without a block supplement. Diet D1 included a urea–molasses–mineral block (B1). While D2 included another type of block (B2) that differed from B1 essentially by adding polyethylene glycol 4000. Each experimental period lasted 33 days (21 days for adaptation and two periods of 5 days for measurement separated by 2 days for rest). Feed intake, apparent digestibility of organic matter (OM), crude protein (CP) and crude fibre (CF) and retained nitrogen (Nr) were measured by total faecal collection. In Experiment II, four Noire de Thibar sheep ( BW =53 kg ) fitted with rumen cannulae were fed sequentially D0, D1 and D2, respectively, to 90% of intake levels as measured in Experiment I on metabolic weight (MW) base. Fermentation parameters in rumen liquid (pH, NH3-N, volatile fatty acid (VFA)) were measured at 0, 2, 5, 8, 10, 13, 16 and 21 h after the morning meal. Protozoal number and composition in rumen fluid were determined at 2 h sampling time. Solid digesta kinetics through the rumen was measured using chromium (Cr) mordanced acacia. The DM and CP degradation of acacia was determined using the nylon bag technique. Acacia had a relatively high content of condensed tannins (41 g kg−1 of DM) and acid detergent lignin (176 g kg−1 of DM). B1 and B2 were high in CP (381 and 369 g kg−1 of DM, respectively) compared to acacia (127 g kg−1 of DM, 20% bound to fibre) and hay (75 g kg−1 of DM). The two kinds of blocks improved similarly (P Both B1 and B2 increased (P

Two experiments were carried out on sheep to measure the effects of some factors of the mobile nylon bag (MNB) technique on the intestinal digestibility (DgI) of rumen undegraded N of meat and bone meal (MBM), soybean meal (SBM) and wheat bran (WB). The pore size of the nylon cloth (10 and 42.5 μm) influenced (P 0.05). Increasing incubation times in the rumen decreased (P < 0.05) DgI of undegraded feed N. The total tract digestibility (rumen plus intestines) was independent of incubation time in the rumen for MBM and SBM, excepted for SBM incubated 4 or 8 h in the rumen when bags were collected in the ileum. Previous ruminal incubation of WB for 4, 8, 16 and 24 h increased (P < 0.05) the amount of N digested in the total tract in comparison with unincubated WB and WB incubated for only 2 h. In the second experiment, residues obtained from the incubation of the feeds in the rumen (0, 2, 4, 8, 16, 24 and 48 h) were mixed in different proportions in order to obtain the true fraction of the undegraded feed in the rumen. This method was based on the DM degradability of the concentrate feeds and the outflow rate constant of feeds from the rumen, supposed equal to 6% h−1. Bags containing feeds mixed according to this method were incubated in a solution of pepsin-HCl for 0, 1, 2 and 3 h to simulate abomasal digestion and the DgI of N was measured afterwards with the MNB technique. Increasing action of pepsin led to higher digestibilities of N at this stage (P < 0.05) but decreased the digestibility of N in the intestines excepted for MBM incubated in pepsin-HCl for 3 h and in any case for SBM. However, the omission of the incubation in pepsin had little influence on the amount of N postruminally digested.

The trypsin inhibitor activity (TIA) of 33 European spring pea varieties was determined. The TIA ofthe varieties Maro, Progreta, Consort and Radley ranged from 6.1 to 8.4 trypsin inhibited units per mg dry matter (TIU mg−1 DM), whereas all the other varieties had ⩽ 3 TIU mg−1 DM. Maro, Progreta and Consort are British varieties of the ‘marrowfat’ type which have classically a high activity. The French winter varieties had a high TIA (mean, 9.1 TIU mg−1 DM), but the varieties arising from a cross between a winter and a spring variety, such as Frilene, Amac, Laser and Santon, had a lower activity. The results were compared with those obtained for six other legume seeds: faba beans, vetches, lentils, pigeonpeas, chickpeas and haricot beans. Finally, a comparison of the TIA of samples of the variety Finale originating from different fields showed that growth conditions influenced the pea TIA. The apparent digestibility of the main constituents of two spring pea varieties (Finale, 2.35 and Progreta, 7.48 TIU mg−1 DM) was determined, by the difference method, using growing pigs with diets consisting of 40% peas. The apparent digestibility of organic matter, crude fibre and crude energy was similar for the two varieties, whereas the apparent digestibility of the crude protein of Progreta was significantly lower (P