Effects of low-protein diets supplemented with crystalline amino acids on performance and intestinal development in piglets over the first 2 weeks after weaning

This study was conducted to determine the effects of low-protein diets supplemented with crystalline amino acids (AA) on performance and intestinal development in barrows (n = 32) over 2 weeks after weaning at 18 ± 1 day. Four maize-soybean meal based diets providing 0.93 g standardized ileal digestible lysine/MJ ME were prepared. The treatments were a control diet containing 23.1% CP (crude protein) and three low-protein diets (21.2, 18.9, and 17.2% CP, respectively), which were supplemented with crystalline AA to achieve an ideal AA pattern. Piglets were raised individually and had free access to feed and water. Average daily gain (ADG) and average daily feed intake (ADFI) were measured weekly. Severity of diarrhea was monitored twice per day. Blood from all piglets was taken for determining serum urea nitrogen on d 0, 7, and 14 and serum free AA concentration on d 14. At the end of the experiment, all piglets were killed to measure morphology of the small intestine and disaccharidase activities. Reducing CP level did not affect ADFI (P > 0.10) but resulted in poorer (linear, P < 0.05; quadratic, P < 0.05) ADG and feed:gain ratio (F:G) over the 2-week study period. However, most of the effect of dietary CP was due to the significant deterioration of performance with the 17.2% CP diet. Faecal consistency was improved linearly (P < 0.01) with dietary CP decrease. Reducing dietary CP from 23.1 to 17.2% resulted in a linear (P < 0.001) and quadratic (P < 0.001) decrease in serum urea nitrogen levels on d 7 and 14. Serum arginine (P < 0.001), glutamine (P < 0.05), and proline (P < 0.05) concentrations were decreased in pigs fed the 17.2% CP diet compared with those fed the control diet on d 14. Villous height was decreased (P < 0.05) in the duodenum and jejunum by the reduction of dietary CP. As dietary CP declined, lactase and sucrase activities were reduced (P < 0.01) in the proximal jejunum. In conclusion, reducing CP concentration from 23.1 to 17.2% led to decreased growth performance associated with morphological changes of the gut and reduced disaccharidase activities in the small intestine. But reducing dietary CP from 23.1 to 18.9% did not affect intestinal morphology and disaccharidase activities.     

Microbial activity in the gut of piglets: I. Effect of prebiotic and probiotic supplementation

Four groups of six 21 days-old piglets were used to evaluate the effect of a prebiotic or probiotic on the intestinal fermentative activity. In each group, piglets received one of the following diets: basal diet (C); basal diet supplemented with xylo-oligosaccharide (C-XOS); basal diet supplemented with Saccharomyces cerevisiae (C-SC); and basal diet supplemented with xylo-oligosaccharide and S. cerevisiae (C-XOS + SC).

The short chain fatty acids in the colon of piglets were decreased with the inclusion of S. cerevisiae in the diet (P < 0.01). The xylanolytic activity was higher (P < 0.05) in the small intestine of piglets fed C-XOS + SC diet, but no significant differences were found in the caecum and colon. In the caecum contents, the cellulolytic activity was increased (P < 0.05) by the C-XOS and C-SC diets, but remained similar when the diet was supplemented with the two additives combined.     

Microbial activity in the gut of piglets: II. Effect of fibre source and enzyme supplementation

Twenty four Duroc × Landrace male piglets, aged 21 days, were assigned to 1 of 4 experimental diets. Diets 1 and 2 contained 150 g kg^− 1 wheat bran and diets 3 and 4 contained 90 g kg^− 1 maize cobs as the major fibre source. All diets contained 480 g kg^− 1 wheat and 200 g kg^− 1 soybean meal. Diets 2 and 4 were supplemented with the following enzyme complex: 800 U/kg cellulase, 1800 U/kg glucanase and 2600 U/kg xylanase.

The replacement of wheat bran by maize cobs increased the acetic (P < 0.05) and decreased the butyric acid production (P < 0.05) in the cecum. Piglets fed diets with maize cobs had lower (P < 0.05) levels of butyric acid in the colon than those fed wheat bran.

The xylanolytic, pectinolytic and cellulolytic enzyme activities were higher (P < 0.05) in the cecum and colon of piglets fed the wheat bran based diets. The supplementation of the diet with the enzyme complex did not significantly affect the levels of short chain fatty acids formed in the small intestine and there was a non significant increase of the levels of acetic, propionic and butyric acids in the cecum and colon of piglets (P < 0.10). No interactions were present between fibre sources and enzyme addition.

The results suggest that the enzyme supplementation of the diet did not bring significant benefits to the animals and that when maize cobs replaces wheat bran in diets it negatively affects butyric acid production and fibre-degrading enzyme activity in the hindgut of piglets.     

The effect of dietary crude protein concentration and inulin supplementation on nitrogen excretion and intestinal microflora from finisher pigs

A 2 × 2 factorial experiment was used to investigate the interaction between dietary crude protein (CP) concentration (200 vs 140 g/kg) and inulin supplementation (0 vs 12.5 g/kg) on nitrogen (N) excretion and intestinal microflora from 16 boars (n = 4, 74.0 kg live weight). The diets were formulated to contain similar concentrations of digestible energy and lysine. Pigs offered the high CP diets had a higher excretion of urinary N (P < 0.01), faecal N (P < 0.01) and total N (P < 0.001) than the pigs offered the low CP diets. Inulin supplementation increased faecal N excretion (P < 0.05) and decreased urine: faeces N ratio (P < 0.05) compared to the inulin free diets. There was no significant effect (P > 0.05) of dietary treatment on N retention. There was an interaction (P < 0.05) between dietary CP concentration and inulin supplementation on caecal E.coli. Pigs offered the diet containing 200 g/kg CP plus inulin decreased the population of E.coli compared to the inulin supplemented 140 g/kg protein diet. However, CP concentration had no significant effect on the population of E.coli in the unsupplemented diets. Inulin supplementation increased caecal bifidobacteria (P < 0.01) compared to the inulin free diets. In conclusion, inulin supplementation favourably altered N excretion and lowered the population of E.coli at high CP concentrations.     

Effect of cooking and fermentation of a pig diet on gut environment and digestibility in growing pigs

The effect of pre-feeding treatment of a pig diet on gut environment and digestibility was studied in a double 3 × 3 Latin-square experiment using growing castrated PVTC cannulated male pigs. The diets were based on local feed resources and were fed raw (R), cooked (C) or naturally fermented (F). There were no differences (P > 0.05) in pH and butyric acid concentration of ileal digesta between diets. However, on diet F concentrations of acetic, lactic and propionic acid in ileal digesta were higher (P < 0.05) than on diets R and C. The relative proportions of individual organic acids in ileal digesta were not a reflection of the fermentation profile found in diet F. The ileal apparent digestibility of crude protein, crude fiber and NDF were higher (P < 0.05) on diet F than on diets R and C. The total tract apparent digestibility of crude protein was higher (P < 0.05) on diet F diet than on diets R and C, while there were no differences in total tract apparent digestibility between diets for any other dietary component. In conclusion, when compared with a pig diet in the raw form, fermentation influenced the gut environment and improved the digestibility of some dietary component, while cooking prior to feeding had no measurable effects.     

Effect of coarse ground corn, sugar beet pulp and wheat bran on the voluntary intake and physicochemical characteristics of digesta of growing pigs

The aim of this work was to evaluate the influence of a coarse ground cereal and two fibrous ingredients incorporated in the diet on the physicochemical properties of digesta and productive parameters of pigs during the first stage of the growing period. A total of 96 pigs (initial body weight, BW, 15 kg) were distributed into four experimental treatments: the control diet (CT) consisted of corn, barley and soybean meal milled to pass through a 2.5 mm screen; the coarse corn diet (CC) was prepared by milling the corn to a coarser particle size (4.0 mm screen); the sugar beet pulp diet (SBP) and the wheat bran diet (WB) were prepared by replacing some of the corn for sugar beet pulp (80 g/kg) or wheat bran (100 g/kg) respectively, in order to contain a higher amount of non-starch polysaccharides (NSP). Three experimental periods were considered (7, 21 and 42 days) during which body weight (BW) and voluntary feed intake were assessed. At the end of each period eight animals per diet were slaughtered. Weight of the gastrointestinal tract and its compartments (full and empty) was recorded and the contents were sampled. Digesta samples were analysed for water concentration, water retention capacity (WRC), ammonia and short-chain fatty acids concentration (SCFA). Histological study of the proximal colon tissues was also performed. In general, the different parameters evaluated showed differences between the experimental periods, but few interactions were recorded. Animals fed CC, SBP and WB diets presented a lower feed intake (P ≤ 0.009) compared to CT fed animals. Compared to the control diet, coarse grinding of corn provoked an increase in the colonic digesta content (P = 0.032). Similarly, animals fed the SBP diet compared to CT animals, showed an increase in the contents (P = 0.009) of hindgut, and in the concentration of water in the digesta (P ≤ 0.011). Compared to CT diet the SBP diet lowered the ammonia concentration in the hindgut contents (P ≤ 0.045) and increased the concentration of SCFA in the distal colon (P ≤ 0.025). Animals fed the SBP diet also showed a lower number of lymphoid nodes in the colonic mucosa compared to the other diets (P ≤ 0.043). Minor modifications were observed associated with the incorporation of wheat bran in the diet, but colonic water from WB fed animals showed a tendency to increase cytolytic capacity. The results confirm major changes in the voluntary intake and physicochemical properties of digesta as affected by the incorporation in the diet of a fibrous ingredient or coarse grinding of cereals.     

Growth performance and metabolic responses in barrows fed low-protein diets supplemented with essential amino acids

This study was conducted to determine the effect of supplementation with Lys, Met, Thr to low-protein diets on growth performance and metabolic responses in growing barrows. Seventy crossbred barrows (Duroc × Yorkshine), with an average initial body weight of 16 kg, were fed diets containing five crude protein (CP) levels (18.2, 16.5, 15.5, 14.5, and 13.6%) and 0.83% true ileal digestible lysine. On d 17 of the trial, all pigs were fitted with an indwelling jugular catheter for blood collection. On d 18 and 53, blood samples were obtained at 4 h post feeding. Reducing dietary CP concentration linearly decreased (P < 0.05) ADG, ADFI, feed efficiency, longissimus muscle area (LMA), and plasma concentrations of urea N and protein, while increasing backfat thickness linearly (P < 0.05). Pigs fed the 13.6% CP diet exhibited the poorest growth performance. On d 53, dietary CP affected plasma IGF-I (quadratic, P < 0.01) and leptin (linear, P < 0.01) concentrations. Plasma leptin levels were correlated positively with backfat thickness (r = 0.76, P < 0.05) and negatively with LMA (r = − 0.64, P < 0.01). There was a positive correlation between ADG and plasma IGF-I concentrations (r = 0.91, P < 0.05). Our results suggest that adequate provision of nonessential AA and all EAA is required for achieving maximum growth performance and reducing fat accretion in growing pigs fed low-CP diets.     

The effects of increasing the level of dietary wormwood (Artemisia montana Pampan) on intake, digestibility, N balance and ruminal fermentation characteristics in sheep

This study investigated the effect of replacing concentrates with dry wormwood (Artemisia montana) on the performance of sheep. Four Corriedale × Polwarth sheep (41.3 ± 1.3 kg) were fed diets with an 8 : 2 straw to supplement ratio, for four, consecutive 16 d periods (10 d adaptation, 6 d collection) in a 4 × 4 Latin square design. Supplements were made by substituting 0 (Control), 30 (LW), 50 (MW) or 100 (HW) g/kg DM of concentrate (15.6% CP, 72.1% of TDN) with dried, ground wormwood. Ruminal pH, NH₃–N and volatile fatty acids (VFA) were measured on d 6 of collection. Ether extract (EE) intake was linearly decreased (P < 0.001) with increasing wormwood inclusion, otherwise intake was unaffected. The Control diet had lower (P < 0.05) DM and CP digestibility than LW and MW diets and lower EE digestibility than the LW diet. Retained N (P < 0.05) and microbial N yield (P < 0.01) linearly increased with dietary wormwood level, but efficiency of microbial N synthesis linearly decreased (P < 0.001). Mean concentrations of rumen NH₃–N, total VFA and propionic acid were quadratically increased (P < 0.05) by increasing wormwood inclusion. Replacing concentrates with 30–50 g/kg DM of wormwood increased N retention, microbial N yield and EE digestibility.     

The effect of quality of grass and maize silage on the intake and performance of beef cattle

A study was undertaken to evaluate the effects of incorporating high (HMS) and low (LMS) maturity maize silages into diets based on low (LGS) and high (HGS) feed value grass silages offered to beef cattle. Seventy-two continental cross-bred steers were used in a 14-week continuous design, randomised block experiment. The six treatments were arranged as a 2 × 3 factorial design incorporating the LGS and HGS offered as the sole forage, along with each of the two grass silages offered in a 60:40 ratio (DM basis) with the HMS and LMS. All diets were supplemented with 3 kg/head/day concentrates. Total daily DM and metabolisable energy intakes were higher (P < 0.001) for diets based on HGS compared to those based on LGS. Intakes were similar (P > 0.05) between diets containing LMS and HMS, both of which were higher (P < 0.001) than diets containing grass silage as the sole forage. Highest DM intakes were recorded with a mixture of HGS and HMS (P < 0.05 or greater). Cattle offered diets containing HGS had higher live-weight gain (P < 0.05), final live weight, carcass gain and carcass weight (P < 0.001) than those offered diets containing LGS. Feed conversion efficiency, assessed on a carcass gain basis, was poorer (P < 0.05) with diets containing LGS compared with those containing HGS, though differences between diets containing either LMS or HMS and GS as the sole forage were not significant (P > 0.05).     

A diet moderately deficient in zinc induces limited intestinal alterations in weaned pigs

The aim of this work was to test the hypothesis that a moderate zinc deficiency induces intestinal alterations in weaned piglets. A diet based on maize and soybean meal was formulated without supplemental zinc (33 ppm, zinc-deficient) or with added zinc (113 ppm, control). These diets were pair-fed for 18 or 27 d to intra-litter pairs of piglets weaned at 21 d of age. The feed intake and growth, plasma concentrations of zinc and alkaline phosphatase (ALP) activity, and morphometry, enzyme activities and the microflora of the mid-jejunum were investigated. Feed intake and growth were similar between diets and diarrhoea was not observed. By contrast, plasma zinc and ALP activity were much lower in zinc-deficient piglets at slaughter (P < 0.001). The weight of organs was unaffected, except colonic tissue that was lighter in piglets fed the zinc-deficient diet (P < 0.05). Neither villus-crypt intestinal architecture nor mucosal enzyme activities were altered. Jejunal counts of lactic acid bacteria and coliforms tended to be higher in the zinc-deficient pigs (P ≤ 0.10). In conclusion, feeding a diet moderately deficient in zinc for 18–27 d induced limited intestinal alterations in weaned pigs.     

Influence of phytase and xylanase supplementation of a wheat-based diet on ileal and total tract digestibility in growing pigs

The effect of phytase and xylanase supplementation of a wheat-based pig diet on the ileal and total tract apparent digestibility of dietary components and minerals were studied in eight growing pigs fitted with a PVTC cannula in a randomized block design experiment. The diets (A and B) were similar in major ingredient composition and in nutrient content. In diet A, part of the limestone was replaced with di-calcium phosphate to increase the content of available phosphorus (P). Diet B was fed without or with supplementation with phytase (500 FTU/kg; diet BP), xylanase (4000 XU/kg; diet BX) and phytase + xylanase (500 FTU and 4000 XU/kg; diet BPX). There were no differences (P > 0.05) between diets in the ileal or total tract digestibility of organic matter (OM), NDF and crude protein (CP). The ileal and total tract digestibility for P and Ca differed (P < 0.05) between diets, while there were no treatment effects for Zn. The ileal and total tract digestibility for P and Ca was higher (P < 0.05) on diets BP and BPX than on the other diets. In conclusion, phytase improved the utilization of dietary P and Ca in a wheat-based diet, while xylanase had no additional benefits in terms of OM and CP digestibility or mineral utilization. Phytase had no effect on the digestibility of OM, CP or NDF.     

Concentrate supplementation responses of the pasture-fed dairy cow

The aim of this study was to investigate the effects of increasing amounts of cereal-based concentrate on milk production. The study consisted of a series of three separate experiments in which cows were grazed in intensive rotation on timothy-meadow fescue pasture. In Experiment 1, 28 multiparous Holstein–Friesian cows received 0, 3, 6 and 9 kg concentrate in a cross-over designed trial with a fixed daily herbage allowance of 21 kg DM/cow. The energy-corrected milk yield increased linearly 0.84 kg/kg DM (P < 0.001), up to the 9 kg concentrate level. The milk fat (P < 0.001) and urea (P < 0.001) content decreased linearly (0.41 g/kg DM and 0.15 mmol/kg DM, respectively). The milk protein content tended (P = 0.08) to increase 0.10 g/kg DM with increasing supplementation.

In Experiment 2, 17 primiparous cows and 28 multiparous cows were used in a randomized-block designed trial with 3, 6 and 9 kg concentrate supplementation and a fixed 25 kg DM herbage allowance. The energy corrected milk yield increased linearly (P < 0.01) 0.67 kg/kg DM, whereas the milk urea content decreased linearly (P < 0.001) 0.27 mmol/kg DM. The milk protein content increased and the fat content decreased, but these differences were not significant.

In Experiment 3, a cross-over design was used to assess the response to concentrate supplementation of 24 multiparous cows (treatments: 6, 9 and 12 kg; fixed herbage allowance 25 kg DM) and 12 primiparous cows (treatments: 4, 7 and 10 kg; herbage allowance > 25 kg DM). The energy-corrected milk yield of the multiparous cows varied quadratically (P_quad < 0.001; 30.0, 32.5 and 32.2 kg for 6, 9 and 12 kg supplementation, respectively). Supplementation linearly decreased the urea (P < 0.001) 0.13 mmol/kg DM and fat (P < 0.001) 0.46 g/kg DM contents. The milk fat content also varied quadratically, showing the lowest content with the 12 kg level (P_quad < 0.05; 37.3, 37.3 and 34.9 g/kg for 6, 9 and 12 kg supplementation, respectively). The energy-corrected milk yield of the primiparous cows increased linearly (P < 0.001) 0.54 kg/kg DM up to 10 kg supplementation, whereas the milk urea (P < 0.001) and fat contents decreased linearly (P < 0.01) by 0.19 mmol/kg DM and 0.61 g/kg DM, respectively.

The results showed that the milk response remained linear up to the 9 kg supplementation level, but the highest level of supplementation resulted in only a marginal increase in milk yield. There was no interaction between season and milk or milk protein yield, which indicates that it is possible to maintain stable grazing conditions during the main grazing season in Nordic latitudes. The results support to some extent the hypothesis that the marginal milk response to supplementation increases with increasing milk production.     

Effect of fibre content in the diet on the mean retention time in different segments of the digestive tract in growing pigs

Development of mechanistic models of digestion is a means to account for interactions between different nutrients, and between nutrients and the animal. Although some digestion models for pigs have been proposed, quantitative information concerning the underlying processes is extremely limiting. The aim of this study was to determine the effect of dietary fibre on the transit of the solid and liquid phases of digesta in different segments of the gastro-intestinal tract (GIT) in growing pigs. Six barrows (initial BW 30 kg and fitted with two simple T-cannulas at the proximal duodenum and distal ileum) were used in a double 3 × 3 Latin square design. Pigs were offered diets differing in total dietary fibre content (17, 22 and 27%) at 4 h intervals. A single meal marked with YbO₂ and Cr-EDTA was used to determine the passage kinetics of respectively the solid and liquid phases of digesta in different segments of the GIT.

The mean retention time (MRT) averaged 1 h from the mouth to the proximal duodenum (stomach), 4 h from the proximal duodenum to the distal ileum (small intestine), and 35 h from the distal ileum to the faecal excretion (large intestine). Increase in dietary fibre content had no effect on MRT in the stomach, tended to decrease MRT of solid phase in the small intestine (P = 0.07), and decreased MRT of both phases in the large intestine (43 to 29 h, P = 0.06). For all diets, transit of the liquid phase in the large intestine was 4–8 h less than transit of the solid phase.     

The effects of weaning age, diet composition, and categorisation of creep feed intake by piglets on diarrhoea and performance after weaning

This study investigated the effects of weaning age, diet, and classification of piglets as ‘eaters’ or ‘non eaters’ of creep feed in lactation, on production and diarrhoea after weaning. Four antimicrobial-free diets were offered in lactation and for 14 days after weaning: (i) wheat–soy based diet with animal and vegetable (‘mixed’) protein sources (COMM), (ii) heat-processed rice (HPR) with barley hulls and potato starch and mixed protein sources (RBHPS), (iii) HPR with sugar-beet pulp and mixed protein sources (RSBP), and (iv) HPR with mixed protein sources (R). Piglets were individually examined for diarrhoea daily for 14 days after weaning, and antibiotic treatments were individually recorded. Faecal swabs were taken on day 10 after weaning and scored for β-haemolytic Escherichia coli. There were significant main effects of weaning age and diet (both P < 0.001) on daily gain between weaning and 14 days after weaning. Pigs weaned later grew 50 g/day more than pigs weaned earlier, and pigs fed the COMM diet grew slower than pigs fed the rice-based diets. The number of antibiotic treatments was influenced by diet (P < 0.001), with most treatments (2.1) given to pigs fed the diet RBHPS. Faecal score was influenced by a weaning age and diet interaction (P < 0.01). There was no correlation (P > 0.05) between the number of antibiotics treatments and the E. coli score.     

Effects of additional zinc and phytase on zinc availability in piglets and chicks fed diets containing different amounts of phytates

Two maize based diets containing 2.3 g phytic P and 38 mg Zn/kg (P+) or 1.3 g phytic P and 25 mg Zn/kg (P−) were formulated. A third diet (P+/Phytase) was P+ supplemented with 3-phytase (500 FTU/kg). Each of these three basal diets, supplemented or not with 15 mg Zn/kg, was given during 20 days to weaned piglets and to 1-day-old chicks. Chicks fed the P− diets were removed from the data set because of an abnormally low feed intake.

In piglets, added Zn increased bone (P < 0.05) and plasma Zn (P < 0.01) irrespective of the basal diet (basal diet × Zn, P > 0.05). Supplementing P+ with phytase was more efficient in improving these indicators of Zn status than replacing P+ by P−. In chicks, supplemental Zn improved Zn status in a higher extent when added to P+ than to P+/Phytase (basal diet × Zn, P < 0.05). Phytase increased Zn status in a lesser extent than 15 ppm supplemental Zn. More Zn was soluble in gizzard than in stomach which corresponded to the differences in pH (4.2 vs 5.0). Phytase increased soluble Zn in stomach (P < 0.05) but not in gizzard. These results suggest a higher availability of Zn in chicks than in piglets in the absence of phytase. This may explain the higher efficacy of phytase for improved Zn availability in piglets than in chicks.     

Supplementation of dietary enzymes has varying effects on apparent protein and amino acid digestibility in reproducing sows

The effects of two enzyme (Enz) products on ileal and total tract digestibility (ID and TTD) were evaluated in sows (n = 8) fed corn–soybean meal diets. Treatments were: 1) control diet; 2) control + Enz 1 (protease and cellulase activity); and 3) control + Enz 2 (xylanase activity). Ileal and fecal samples were collected at week 6–7 and 12–13 of gestation and week 2–3 of lactation. There were no improvements in digestibility during gestation. The ID% of dry matter (DM: 77.3, 79.3, 81.7) and N (81.2, 82.5, 84.3) as well as TTD% of DM (89.8, 90.7, 90.8) and N (89.0, 90.0, 90.6) during lactation were affected to varying degrees by the enzymes. The TTD of DM (P = 0.05) and N (P = 0.10) were positively affected by Enz 1. The ID of DM (P = 0.01) and N (P = 0.02) as well as TTD of DM (P = 0.05) and N (P = 0.02) were improved by Enz 2. The improvement in ID of N was not associated with any particular amino acids (AA) but represented small increases in ID of 8 of 10 essential AA with Enz 1 (P = 0.04) and 10 of 10 for Enz 2 (P = 0.01). The product containing xylanase activity, in particular, appears to have potential to increase digestibility of nutrients during lactation in sows.     

Xylanase supplementation improves energy digestibility of wheat by-products in grower pigs

Value-added processing of cereals produces high-value fractions for food and bio-processing application and by-products that are used in animal nutrition to reduce feed costs. Wheat by-products contain arabinoxylans that might limit nutrient digestibility. Effects of xylanase supplementation (0 or 4375 U/kg feed) on energy digestibility were studied in a wheat control and by-product diets (30% millrun, middlings, shorts, screenings, and bran) in a 2 × 6 factorial arrangement. The wheat control diet was formulated to contain 3.34 Mcal digestible energy (DE)/kg and 2.8 g apparent digestible lysine/Mcal DE, and included 0.4% chromic oxide as a marker for digestibility. Twelve ileal-cannulated pigs (32.5 ± 2.5 kg) were each fed seven of 12 diets. Faeces and then digesta were each collected for 2 d, and diet digestibility values are reported. Wheat had higher ileal and total-tract energy digestibility than by-products (P < 0.01). Xylanase improved energy digestibilities for by-products (P < 0.001) but not for wheat. Among by-products, ileal energy digestibility was lowest for middlings (62%), then bran < screenings < millrun, and highest for shorts (66%). Xylanase improved (P < 0.05) ileal energy digestibility of millrun by 19% to 76%. Total-tract energy digestibility of millrun improved from 72 to 79% (similar to wheat) with xylanase (P < 0.05). In summary, xylanase improved energy digestibility in the selected wheat by-product diets, indicating that arabinoxylans in wheat by-products limit nutrient digestibility.     

Effect of adding Lactobacillus plantarum or a formic acid containing-product to fermented liquid feed on gastrointestinal ecology and growth performance of piglets

A study was carried out to investigate whether adding a starter culture or a formic acid containing-product to fermented liquid feed of suboptimal microbial quality could improve the characteristics of the mixture and the gastrointestinal ecology and growth performance of piglets. Four experimental diets were prepared: Feed and water were mixed in the ratio 1:2.5 (w/w) in four closed tanks. Diet 1) Three times daily, 50% of the mixture stored in the tank was removed and then replaced with an equal amount of fresh feed and water, (FLF), positive control; Diet 2) Three times daily, 95% of the mixture stored in the tank was removed and then replaced with an equal amount of fresh feed and water. Escherichia coli K12 (1 × 10⁶/g) was added every morning (COLI); Diet 3) as the COLI treatment and added Lactobacillus plantarum VTT E-78076 (1 × 10⁶/g) every morning (+PLANTARUM); and Diet 4) as the COLI treatment and added 0.26 g AIV/KemiSile 2 plus/100 g mixture three times daily (+ACID). One hundred and sixty weaners were used. On day 14, one littermate from each pen was killed and the gastrointestinal tract removed. The remaining piglets were used to measure the effect of the experimental diets on growth performance during the first six weeks post-weaning. The +ACID diet had lower numbers of lactic acid bacteria and Enterobacteriaceae, higher numbers of yeasts, and lower concentration of lactic acid and acetic acid than the COLI and +PLANTARUM diets. Feeding the +PLANTARUM and the +ACID diets increased daily weight gain during the six weeks post-weaning (P ≤ 0.02) compared to feeding the COLI diet. The +ACID group showed the highest numerical daily feed intake in all periods. The gain/feed during the six weeks post-weaning tended to be lowest in the COLI group (P < 0.10). The counts of lactic acid bacteria able to grow at 20 °C were lowest in the stomach (P ≤ 0.003) and distal small intestine (P ≤ 0.06) of the +ACID group. The counts of yeasts able to grow at 37 °C in the stomach were highest in the +ACID (P ≤ 0.01) and FLF groups (P ≤ 0.09). The number of yeasts able to grow at 20 °C in the stomach and distal small intestine was highest in the FLF fed piglets, followed by the +ACID group. This study showed that addition of L. plantarum VTT E-78076 or AIV/KemiSile 2 plus to fermented liquid feed of suboptimal microbial quality improved growth performance without affecting the gastrointestinal ecology of piglets substantially.     

Changes in hormones, growth factor and lipid metabolism in finishing pigs fed betaine

An experiment was conducted to investigate the effect of dietary betaine supplementation on carcass characteristics, hormones, growth factor and lipid metabolism in finishing pigs. Forty-eight crossbred barrows and gilts (Seghers × Seghers × Duroc) weighing about 55 kg were divided into two groups, each with three replicates of eight pigs (four barrows and four gilts) per replicate, and fed corn–soybean meal basal diets supplemented with 0 and 0.125% betaine for 42 days. At trial termination, two pigs (one barrow and one gilt) weighing about 90 kg were selected from each replicate and slaughtered for analyses. The results showed that betaine increased carcass lean percentage and longissimus muscle area by 5.19% (P < 0.01) and 17.85% (P < 0.01), respectively, and decreased carcass fat percentage and average backfat thickness by 13.07% (P < 0.01) and 10.30% (P < 0.05), respectively. Serum growth hormone, insulin-like growth factor I, free triiodothyronine, free thyroxine and insulin levels in pigs fed betaine were elevated by 45.61% (P < 0.01), 55.50% (P < 0.01), 57.95% (P < 0.01), 51.80% (P < 0.01) and 42.34% (P < 0.05), respectively. Fatty acid synthase activity in the 10th rib subcutaneous adipose tissue was decreased by 24.35% (P < 0.05) with betaine supplementation, whereas hormone-sensitive lipase activity was significantly increased (P < 0.05). Meanwhile, serum free fatty acids concentration in betaine-fed pigs was 25.75% higher compared to controls (P < 0.01). The study suggested that betaine could induce changes in hormones and growth factor in finishing pigs, and therefore could inhibit fat synthesis through reducing lipogenic enzymes activities and promote fat degradation by increasing hormone-sensitive lipase activity, with a resultant decrease in adipose tissue mass and improvement in carcass characteristics.     

Effect of an enzyme complex derived from Trichoderma longibrachiatum on ileal digestibility of amino acids and non-starch polysaccharides in piglets

A digestibility trial on piglets was conducted to study the effect of an enzyme complex derived from Trichoderma longibrachiatum (Roxazyme G2) supplemented to a rye-based diet on apparent ileal digestibility of amino acids and NSP-constituting sugars. Enzyme supplementation at 200 mg kg^− 1 increased (P < 0.05) the digestibility of total amino acids from 67.1 to 70.8. As the dietary concentration of Roxazyme G2 increased from 0 to 100 mg/kg, the ileal digestibility of the NSP constituents gradually increased. No further increase was observed with the supplementation level of 200 mg/kg. The improvement in the digestibility of arabinose + xylose (685%, P < 0.05) was much higher than that of the remaining sugars (110%, P < 0.05). The apparent ileal digestibility of galactose was positively influenced by Roxazyme G2 but it remained negative in all dietary treatments, presumably due to the high concentration of galactose in endogenous secretions. It is concluded that Roxazyme G2 effectively degrades non-starch polysaccharides in upper digestive tract and marginally improves amino acid availability in young pigs.