Influence of micronization (fine grinding) of soya bean meal and full-fat soya bean on the ileal digestibility of amino acids for broilers

A trial was conducted to test the effect of fine grinding (micronization) of soya bean meal (SBM) and full-fat soya bean (FFSB) on coefficient of ileal apparent digestibility (CIAD) and coefficient of ileal true digestibility (CITD) of amino acids in 23-day-old broilers. A completely randomized block design with four treatments arranged factorially (SBM and FFSB; micronized and ground) and six replicates (eight broilers per treatment) was used. Mean particle size (MPS) was 47 and 41 μm for micronized SBM and FFSB and 881 and 778 μm for ground SBM and FFSB, respectively. The four diets were based on maize starch and sucrose with the soya product tested as the sole source of dietary crude protein (CP, 200 g/kg). In addition, a nitrogen-free diet was formulated to estimate the basal ileal endogenous losses of the amino acids. Broilers were fed a commercial pelleted maize-SBM diet from 1 to 19 days of age and, then, their respective experimental diets in mash form from 20 to 23 days of age. Broilers fed SBM had higher CIAD of organic matter, CP, arginine, leucine, methionine and valine (P<0.05) and tended to have higher CIAD of threonine (P<0.10) than broilers fed FFSB. In addition, broilers fed SBM had higher CITD of CP (P<0.05), leucine, methionine and valine (P<0.01) than broilers fed FFSB. Particle size did not affect the ileal digestibility of CP or of any of the essential amino acids. It is concluded that broilers fed soya bean meal had higher ileal digestibility of amino acids than broilers fed full-fat soya bean and that fine grinding of the soya products did not affect amino acid digestibility.     

Influence of micronization (fine grinding) of soya bean meal and fullfat soya bean on productive performance and digestive traits in young pigs

Two trials were conducted to test the effect of micronization (very fine grinding) of soya bean meal (SBM) and fullfat soya bean (FFSB) on productive performance and digestive traits of piglets. The experimental design was completely randomized with four treatments arranged factorially (SBM and FFSB, micronized and ground). The mean particle size (MPS) was 47 and 881 μm for the SBM and 41 and 778 μm for the FFSB, micronized and ground, respectively. In trial 1 growth traits from 23 to 45 days of age and the coefficient of total tract apparent digestibility (CTTAD) of dietary components at 33 and 45 days of age were assessed. In trial 2 the coefficient of ileal apparent digestibility (CIAD) of dietary components, the pH of the gastro intestinal tract (GIT) and the weight of digestive organs and spleen were measured at 45 days of age. From 23 to 33 days of age pigs fed SBM grew faster (253 g/d versus 213 g/day; P<0.05) and were more efficient (0.87 g/g versus 0.98 g/g; P<0.01) than pigs fed FFSB. For the entire experiment (23–45 days of age) pigs fed SBM tended to grow more (360 g/day versus 324 g/day) and to eat more feed (414 g/day versus 380 g/day) than pigs fed FFSB (P<0.10). The CTTAD of crude protein (0.798 g/kg versus 0.778 g/kg), organic matter (0.864 g/kg versus 0.839 g/kg) and gross energy (0.849 g/kg versus 0.830 g/kg) were higher for pigs fed SBM than for pigs fed FFSB (P<0.001). In addition, CIAD of organic matter (0.765 g/kg versus 0.705 g/kg) and gross energy (0.761 g/kg versus 0.711 g/kg) were higher for SBM than for FFSB diets (P<0.001). The pH of the different segments of the GIT was not affected by the protein source (P>0.10). Particle size did not affect any trait studied (P>0.10). The poor performance and digestibility of pigs fed FFSB as compared to pigs fed SBM might be related to the conditions applied during processing. It is concluded that pigs fed soya bean meal perform better than pigs fed FFSB and that micronization of the soya protein sources does not affect any trait studied.     

Lupinus luteus,Vicia sativa and Lathyrus cicera as protein sources for piglets: ileal and total tract apparent digestibility of amino acids and antigenic effects

Twenty-four male piglets, weaned at 28 days of age, were used to measure the total and ileal digestibility and serum immune responses to dietary leguminous seeds. The experimental diets consisted of a control starter (C) and three other diets prepared by replacing 30% of the crude protein content of the C diet by the protein of Lupinus luteus (LL), Vicia sativa (VS) or Lathyrus cicera (LC). The total tract apparent digestibility (TTAD) of energy and crude protein (CP) was lowest (P<0.001) for the LC diet. Similarly TTAD of lysine, methionine and threonine were also lowest for the LC diet. The apparent ileal digestibility (AID) of lysine, methionine and threonine were lowest for the LC diet. AID of lysine and methionine was highest for the LL seeds (0.764 and 0.834, respectively) and lowest (P<0.05) for the LC seeds (only 0.454 and 0.420, respectively). Immunoblots of individual pig serum were made to detect both residual antigenic storage proteins of the seeds of each legume used and IgGs specific to those storage proteins. Antibodies against β-conglutin of L. luteus, vicilin of V. sativa and vicilin of L. cicera were detected 28 days after feeding the diet in the sera of piglets fed on the LL, VS or LC diets, respectively. Conversely, no storage protein was found in the serum of any piglet fed either on LL, VS or LC diets. The presence of antibodies against β-conglutin of lupine, vicilin of V. sativa and vicilin of L. cicera, respectively indicated an immune response in weaned piglets. The absence of residual antigenic proteins may be due to the digestive adaptation of the piglet to the legume-based diets. However, no direct relation between the differences in digestibility coefficients among the legume seeds and their antigenicity was established.     

Meat meal in the diet of the early-weaned pig. I. A comparison of meat meal and soya bean meal

Seventy-two pigs, initially weighing 4–5 kg, were fed on wheat-based diets supplemented with soya bean meal and/or meat meal in two experiments each of 4 weeks' duration.In the first experiment, 0, 25, 50 or 100% replacement of soya bean meal protein supplement with meat meal was associated with a linear decrease in weight gains (341-280 g/d), a linear increase in feed conversion ratios (1.64–2.35) and a linear decrease in apparent digestibility of dry matter (80.1–73.4%). There was no change in the apparent digestibility of nitrogen.In the second experiment, bone meal was added to provide 0.80, 1.55 and 3.05% calcium in diets in which the protein supplements were either soya bean meal or meat meal. The addition of bone meal to the diets containing soya bean meal did not affect the performance of the pigs, but it caused a linear decrease in the apparent digestibility of dry matter, nitrogen and calcium. The addition of bone meal to the diet containing meat meal reduced the feed intakes of the pigs from 617 to 516 g/d and the weight gains from 414 to 324 g/d.Weight gains of pigs were similar when their diets contained soya bean meal or meat meal as the protein supplement in the second experiment when the calcium content of the diets was 0.8%. The meat meal included in the diet was manufactured from soft offal.     

Influence of dietary fibre on nutrient digestibility and energy utilisation in growing pigs fed diets varying in soluble and insoluble fibres from co-products

The co-products from the industry are used to reduce costs in pig diets. However, the co-products used in pig diets are limited because of a high fibre content which is not digested by endogenous enzymes and is resistant to degradation in the small and large intestines. The aim of this study was to investigate digestibility of nutrients and energy, and energy utilisation in pigs fed diets with various soluble and insoluble dietary fibre (DF) from co-products. The experiment was performed as a 4 × 4 Latin square design (four diets and four periods) using four growing pigs (66.2 ± 7.8 kg) surgically fitted with a T-cannula in the end of the small intestine. The pigs were fed four experimental diets: low-fibre control (LF), high-fibre control (HF), high-soluble fibre (HFS) and high-insoluble fibre (HFI) diets. The apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of ash, organic matter, CP, fat, carbohydrates, starch and non-starch polysaccharides (NSP) divided into cellulose and soluble and insoluble non-cellulosic polysaccharide residues were measured using chromic oxide as marker. The recovery of total solid materials, organic matter and total carbohydrates in ileal digesta in pigs fed the HF and HFS diets was higher than in pigs fed LF and HFI, whereas recovery of organic matter and total carbohydrates in faecal materials in the HFS diet was lowest (P < 0.05). AID of organic matter, total carbohydrates and starch was lowest for HFS diet (P < 0.05). ATTD of organic matter and CP was higher for LF diet compared with other diets (P < 0.05), whereas total NSP, cellulose and non-cellulosic polysaccharides residues were highest for HFS diet (P < 0.05). Lactic acid in ileal digesta was influenced by dietary composition (P < 0.05) whereas neither type nor level of DF affected short chain fatty acids. The digestible energy, metabolisable energy, net energy and retained energy intake were similar among diets without influence of DF inclusion (P > 0.05). The metabolisable energy:digestible energy ratio was lower when feeding the HFS diet because of a higher fermentative methane loss. Faecal nitrogen and carbon were positively correlated with DM intake and insoluble DF in the diets (P < 0.05), but nitrogen and carbon (% of intake) were similar among diets. The present findings suggest that high-DF co-products can be used as ingredients of pig diets when features of DF are considered.     

Effects of balancing crystalline amino acids in diets containing heat-damaged soybean meal or distillers dried grains with solubles fed to weanling pigs

Two experiments were conducted to investigate if adjustments in diet formulations either based on total analysed amino acids or standardized ileal digestible (SID) amino acids may be used to eliminate negative effects of including heat-damaged soybean meal (SBM) or heat-damaged corn distillers dried grains with solubles (DDGS) in diets fed to weanling pigs. In Experiment 1, four corn–SBM diets were formulated. Diet 1 contained non-autoclaved SBM (315 g/kg), and this diet was formulated on the basis of analysed amino acid concentrations and using SID values from the AminoDat® 4.0 database. Diet 2 was similar to Diet 1 in terms of ingredient composition, except that the non-autoclaved SBM was replaced by autoclaved SBM at 1 : 1 (weight basis). Diet 3 was formulated using autoclaved SBM and amino acid inclusions in the diet were adjusted on the basis of analysed total amino acid concentrations in the autoclaved SBM and published SID values for non-autoclaved SBM (AminoDat® 4.0). Diet 4 also contained autoclaved SBM, but the formulation of this diet was adjusted on the basis of analysed amino acids in the autoclaved SBM and SID values that were adjusted according to the degree of heat damage in this source of SBM. Pigs (160; initial BW: 10.4 kg) were allotted to the four treatments with eight replicate pens per treatment in a randomized complete block design. Diets were fed to pigs for 21 days. The gain to feed ratio (G : F) was greater (P<0.05) for pigs fed Diet 1 compared with pigs fed the other diets and pigs fed Diet 4 had greater (P<0.05) G : F than pigs fed Diet 2. In Experiment 2, 144 pigs (initial BW: 9.9 kg) were allotted to four diets with eight replicate pens per diet. The four diets contained corn, SBM (85 g/kg) and DDGS (220 g/kg), and were formulated using the concepts described for Experiment 1, except that heat-damaged DDGS, but not heat-damaged SBM, was used in the diets. Pigs fed Diet 1 had greater (P<0.05) G : F than pigs fed Diet 2, but no differences were observed for G : F among pigs fed diets containing autoclaved DDGS. Results demonstrate that the negative effects of heat damage of SBM or DDGS may be ameliorated if the reduced concentration and digestibility of amino acids in heat-damaged SBM or DDGS is taken into account in diet formulation. Further research is needed to improve the prediction of the ileal digestibility of amino acids in heat-processed ingredients used in practical diet formulations.     

Nutrient digestibility in Atlantic salmon and broiler chickens related to viscosity and non-starch polysaccharide content in different soyabean products

Total tract digestibility in Atlantic salmon and ileal digestibility in chicken were assessed from diets with different soyabean products (hulled, toasted, extracted, SBM; reduced oligosaccharide content, ROM; ethanol-extracted protein concentrate, SPC; isolated protein, ISP). The concentration of dietary fibre was highest in SBM and ROM, while it was low in ISP. In vitro viscosity was also higher in SBM than in the other soyabean products. The diets for the salmon and chickens were based on the same feed ingredients, with the exception that fish meal provided half the crude protein in the salmon diets. For each species, the diets were isonitrogenous, contained similar amounts of fat (fish oil), and were balanced with dextrin, thus substituting soyabean non-starch polysaccharides (NSP) and other non-proteinous components by dextrin.In the salmon, total tract digestibility of nitrogen and dry matter were lower (p < 0.05) with the SBM and ROM diets than with the ISP diet. In the chickens, ileal digestibility of dry matter differed among all treatments (p < 0.05). Digestibility of nitrogen, starch, phosphorus and calcium in the chickens was lower (p < 0.05) with the SBM diet than with the ISP and SPC diets, and fat digestibility was lower (p < 0.05) with the SBM and ROM diets than with the SPC diet. Also, the SBM diet gave lower (p < 0.05) digestibility of nitrogen, phosphorus and calcium than the ROM diet, while the ROM diets gave lower (p < 0.05) digestibilities of nitrogen, fat and starch than the ISP and SPC diets. Intestinal viscosity was higher (p < 0.05) and cholesterol content in the blood was lower (p < 0.05) for the chickens fed the SBM-based diet than those fed the other diets. There was a similar response to the different soy products in salmon and chickens with regard to digestibility of nitrogen and fat (p < 0.05). The negative effects of soyabean meals with a low protein content could indicate antinutritive effects of NSP fractions in soyabean meal, as indicated by the elevated viscosity and the decrease in blood cholesterol content.     

Apparent protein digestibility and recovery of endogenous nitrogen at the terminal ileum of pigs fed diets containing various soyabean products, peas or rapeseed hulls

Effects of the use of three different soyabean products (soya concentrate and two different soyabean meals), peas or rapeseed hulls in the diet on the apparent ileal digestibility of CP (N × 6.25) and recovery of ileal endogenous nitrogen (N) in weanling pigs were investigated. Ileal endogenous N was measured using the ¹⁵N-isotope dilution method. Thirteen castrated male pigs (BW of 12–23 kg) were fed maize starch-based diets containing either soya concentrate (SC), purified rapeseed hulls (pRH) and SC (SRH diet), soyabean meal (SBM), a mixture of toasted and untoasted soyabean meal (mSBM) or peas. The apparent ileal digestibility (AID) of dry matter (DM) for the SC, SRH, SBM, mSBM and pea diets was 82.1, 74.3, 83.3, 80.0 and 74.9% (P < 0.05), respectively. The AID of CP for these diets was 82.4, 67.6, 81.6, 68.0 and 76.9% (P < 0.05), respectively. Similar differences in the AID for amino acids (AA) in the diets were found. The AID for CP and for the sum of AA in the pRH, as calculated by the difference between the SC and SRH diet, were 26 and 41%, respectively. For the SC, SRH, SBM, mSBM and pea diet, ileal recovery (g/kg of DM intake) for endogenous N were 2.79, 3.46, 2.73, 4.89 and 3.29 (P < 0.05), respectively, and for dietary N 1.16, 4.11, 1.64, 4.15 and 2.53 (P < 0.05), respectively. For the SC, SBM and mSBM diets, differences in AID of CP and AA were associated with differences in both the ileal recovery of endogenous N and the recovery of undigested dietary N. Differences in trypsin inhibitor activity (TIA) of the soya products were likely associated with these observations. It was also concluded that fibre (Neutral Detergent Fibre; NDF) in pea could be at least in part responsible for the relatively low AID of CP and AA and the high recovery of ileal endogenous N in the pea diet. The low AID of CP and AA of pRH was likely related to the association of protein to the fibre matrix in the fibre-rich rapeseed hulls.     

Simultaneous inclusion of sorghum and cottonseed meal or millet in broiler diets: effects on performance and nutrient digestibility

Two experiments were conducted to investigate the use of sorghum, cottonseed meal and millet in broiler diets and their interaction when they are used simultaneously. In Experiment 1, a corn-soybean meal control diet was compared with eight experimental treatments based on low tannin sorghum (S30, S45 and S60), cottonseed meal (CM15, CM40) or both ingredients included in the same diet (S30/CM40, S45/CM25 and S60CM15). Results showed that BW gain was not affected by the inclusion of sorghum or cottonseed meal. However, feed intake tended to be affected by the cereal type with the highest values with sorghum-based diets. Feed conversion ratio increased (P<0.001) with sorghum-based diets compared with the control diet, whereas a combination of cottonseed meal and sorghum in the same diet did not affect the feed conversion ratio. Significant differences (P<0.001) were observed in apparent ileal digestibility (%) of protein and energy with the cottonseed meal and sorghum/cottonseed meal-based diets having lower protein and energy digestibility compared with corn-based diets. In Experiment 2, a control diet was compared with six diets in which corn was substituted at 60%, 80% or 100% by either sorghum or millet and other three diets with simultaneous inclusion of these two ingredients (S30/M30, S40/M40, S50/M50). Single or combined inclusion of sorghum and millet resulted in similar feed intake and growth performance as the control diet. Apparent ileal digestibility of protein and energy was higher with millet-based diets (P<0.001). Total tract digestibility of protein in sorghum and millet-based diets tended to decrease linearly with the increasing level of substitution. Sorghum-based diets resulted in lower total tract digestibility of fat compared with millet and sorghum/millet-based diets (P<0.001). Higher total tract digestibility of starch were obtained with the control diet and millet-based diets compared with the sorghum-based treatments. Results of the two experiments suggest that broiler growth performance was not affected by the dietary level of sorghum, millet or cottonseed meal. Nutrient digestion can, however, be affected by these feed ingredients.     

Nutritional value and mercury content of fish silage for growing pigs

The dry matter content of 18 samples of fish silage prepared from fish species or prawn offal varied from 190 to 274 g/kg (mean 239). Chemical composition (mean and range, g/kg dry matter) was: crude protein 686 (487–882); ether extract 100 (53–211); ash 163 (105–319); and total mercury 1.05 mg/kg (0.24–4.05 mg/kg).The nutritional value of fish silage, prepared from Ocean perch and Nannygai, was investigated for grower pigs. Wheat-based diets were formulated in which fish silage partially or completely replaced soya been meal as the protein supplement. The diets were evaluated over the 20 to 45 kg growth phase. Half the pigs were slaughtered at 45 kg live weight; the remainder were fed on the wheat and soya bean meal diet to 80 kg live weight in order to observe the effect of withdrawal of fish silage at 45 kg on subsequent growth performance and mercury content in the lean tissue.The addition of fish silage improved growth rate (P < 0.05) and food conversion ratio (P < 0.01) during the 20 to 45 kg growth phase. No adverse effects on carcass quality were observed. During the 45 to 80 kg growth phase, when all pigs were fed on the wheat and soya bean meal diet, all produced similar performance. Over the 20 to 80 kg growth phase, the beneficial effects of fish silage on growth rate and feed conversion were maintained.Methyl mercury content in the semi-membraneous muscle of pigs fed on fish silage and slaughtered at 45 kg live weight was 0.085 mg/kg on a wet weight basis. This decreased to 0.018 mg/kg in pigs that had the fish silage withdrawn from the diet during the 45 to 80 kg growth phase.     

Amino acid utilization and body composition of growing pigs fed processed soybean meal or rapeseed meal with or without amino acid supplementation

Feed ingredients used in swine diets are often processed to improve nutritional value. However, (over-)processing may result in chemical reactions with amino acids (AAs) that decrease their ileal digestibility. This study aimed to determine effects of (over-)processing of soybean meal (SBM) and rapeseed meal (RSM) on post-absorptive utilization of ileal digestible AAs for retention and on body AA composition of growing pigs. Soybean meal and RSM were processed by secondary toasting in the presence of lignosulfonate to obtain processed soybean meal (pSBM) and processed rapeseed meal (pRSM). Four diets contained SBM, pSBM, RSM or pRSM as sole protein source. Two additional diets contained pSBM or pRSM and were supplemented with crystalline AA to similar standardized ileal digestible (SID) AA level as the SBM or RSM diet. These diets were used to verify that processing affected AA retention by affecting ileal AA digestibility rather than post-absorptive AA utilization. The SID AA levels of the protein sources were determined in a previous study. In total, 59 pigs were used (initial BW of 15.6±0.7 kg) of which five were used to determine initial body composition at the start of the experiment. In total, 54 pigs were fed one of six experimental diets and were slaughtered at a BW of 40 kg. The organ fraction (i.e. empty organs plus blood) and carcass were analyzed separately for N and AA content. Post-absorptive AA utilization was calculated from AA retention and SID AA intake. An interaction between diet type, comprising effects of processing and supplementing crystalline AA, and protein source was observed for CP content in the organ fraction, carcass and empty body and for nutrient retention. Processing reduced CP content and nutrient retention more for SBM than for RSM. Moreover, processing reduced (P<0.001) the lysine content in the organ fraction for both protein sources. Supplementing crystalline AA ameliorated the effect of processing on these variables. Thus, the data indicated that processing affected retention by reducing digestibility. Correcting AA retention for SID AA intake was, therefore, expected to result in similar post-absorptive AA utilization which was observed for the RSM diets. However, post-absorptive AA utilization was lower for the pSBM diet than for the SBM diet which might be related to an imbalanced post-absorptive AA supply. In conclusion, processing negatively affected nutrient retention for both protein sources and post-absorptive utilization of SID AA for retention for SBM. Effects of processing were compensated by supplementing crystalline AA.     

Evaluation of microbially enhanced soybean meal as an alternative to fishmeal in weaned pig diets

An experimental, microbially enhanced soybean product (MEPRO) was evaluated as a replacement for fishmeal (FM). Assessment of feedstuffs should include estimation of digestibility as well as pig performance and in combination with dietary additives. Digestibility values determined in growing pigs may not apply to nursery pigs; thus, standardized ileal digestibility (SID) of amino acids (AA) in MEPRO and FM were determined using 30±1.6 kg BW ileal-cannulated barrows (n=6) and 9.8±1.2 kg BW barrows (n=37; serial slaughter). Experimental diets included MEPRO, FM and nitrogen free where FM and MEPRO were included as the sole protein source. The SID of AAs was 3% to 5% lower in MEPRO than FM when fed to 30 kg pigs. The SID of arginine and methionine was greater (P<0.05) in MEPRO than FM when fed to 10 kg pigs. The SID of AAs was 12% to 20% lower in FM when fed to 10 v. 30 kg pigs but only 3% to 9% lower in MEPRO. A total of 336 barrows and gilts were weaned at 21 days of age (initial BW=6.1±0.8 kg) and used in a performance trial. Pens of pigs were assigned to one of the six experimental diets (8 pens/diet in two blocks). Treatment diets were fed in Phase I (7 days) and Phase II (14 days) with all pigs fed a common Phase III diet (14 days). Experimental diets included (1) negative control (NEG) containing corn, soybean meal and whey, (2) NEG+acidifier, (3) NEG+FM (POS), (4) POS+acidifier (POS A+), (5) NEG+MEPRO (MEPRO) and (6) MEPRO+acidifier. The FM and MEPRO were included at 7.5% and 5.0% in Phase I and II diets, respectively. Diets were formulated to meet the standard nutrient requirements for weaned pigs. Pig BW and feed disappearance was measured weekly and fecal scores were measured daily for the first 14 days post-weaning as an indicator of post-weaning diarrhea syndrome (PWDS). Performance (BW, daily gain, feed intake and gain : feed) was not significantly different among treatments. Treatment for PWDS occurred on different days in each block. Analysis of fecal score was completed separately by block. Pigs fed the NEG diets had higher (P=0.02) fecal scores than pigs fed the POS diets on days 2 and 3 (block 1) and higher (P<0.05) than pigs fed MEPRO or POS diets and diets with dietary acidifier on days 6 and 3 (block 2). The MEPRO holds promise as an alternative to FM in nursery pig diets.     

Effect on digestion and performance of dietary protein content and of increased substitution of lucerne hay with soya-bean protein concentrate in starter diets for young rabbits

The aim of this work was to study the effect of protein source / availability on the intestinal microbiota, digestive traits and nutritional performance of early-weaned rabbits. The effects of supplemental antibiotics in the drinking water were also evaluated. Four isoenergetic and isofibrous diets were formulated: a control diet with a high protein (207 g/kg dry matter (DM)) and lucerne hay content (HPHL), a diet with low crude protein (CP) (179 g/kg DM) and high lucerne hay content (LPHL) and low protein diets in which the lucerne hay in diet LPHL was replaced partially (LPML) or totally (LPLL) with soya-bean protein concentrate. Rabbits, weaned at 25 days (52 per diet), were fed the experimental diets for a 2-week period and thereafter received a commercial diet until 56 days of age. The incidence of mortality was investigated using 70 animals per diet without supplemental medication. The profile of the ileal microbiota was studied at 35 days of age in rabbits treated (18 per diet) or not (12 per diet) with antibiotic. As expected, supplementation with antibiotics effectively reduced fattening mortality rate and microbial biodiversity. However, lowering of also the dietary CP content led to a reduction in the mortality rate ( P < 0.05), both in animals treated with (by 80%) or without (by 39%) antibiotics. In addition, there was a reduction ( P < 0.05) in the frequency of Clostridium perfringens in non-medicated animals. Neither jejunal morphology nor growth performance, over the whole fattening period, was affected by dietary CP content of the experimental diets. However, with HPHL, feed efficiency was higher (by 4.8%; P < 0.01) than with LPHL diets. Substitution of lucerne hay with soya-bean meal in low protein diets did not affect apparent faecal or ileal digestibility of DM and CP. However, the ileal digestibility of cystine, alanine, aspartic acid, and proline was lowered ( P < 0.05) with increasing substitution by soya bean. Nevertheless, ileal CP flow, incidence of mortality and presence of C. perfringens were unaffected. Our results suggest that a reduction in dietary CP, resulting in reduced lumenal flows of nitrogen through the ileum, may be beneficial for young rabbits and limit the numbers of potentially harmful bacteria in the lower gut. Modulation of dietary CP should be contemplated as a strategy to increase the intestinal health in rabbits.     

Effect of microbial phytase on apparent ileal amino acid digestibility of phosphorus-adequate diets in growing pigs

Six ileally cannulated pigs (mean initial body weight 34.8 kg) were used to study the effect of microbial phytase on apparent ileal digestibility of P, total N and amino acids. Three P-adequate diets (digestible P concentration 2.3 g kg(- )l) containing barley (B), soyabean meal (S) or a mixture of the two (BS) with or without phytase supplement (1000 FTU x kg(-1)) were fed to pigs using a 6 x 6 Latin square design. The addition of phytase increased (p < 0.05) apparent ileal P digestibility of diets B, S and BS by 16.5, 19.2 and 19.2%, respectively. There was no effect of phytase on the ileal digestibility of total N. Apparent ileal digestibility of amino acids tended to increase in the BS diet supplemented with phytase (mean improvement of 2.2%); but no significant difference was found for any amino acid as compared with the unsupplemented diet. To asses the additivity of apparent amino acid digestibility, the determined values for the BS diet were compared to those calculated from digestibilities found in diets B and S. There were no significant differences between the determined and calculated values. It is concluded that the addition of microbial phytase to P-adequate diets does not affect ileal amino acid digestibility in growing pigs and that the apparent amino acid digestibility values determined in single ingredients may be additive when included into a complex diet.     

Effects of diets differing in protein source and technical treatment on digestibility,performance and visceral and biochemical parameters of fattening pigs

The aim of the experiment on 100 cross-bred barrows was to compare commercial diets for fattening pigs based on either soya bean meal (SBM) imported from non-European countries with diets based on a mixture of locally produced rape seed meal, distillers’ dried grains with solubles and soya beans as main protein sources. In addition, these both types of diets were processed by two different technical feed treatments, i.e. coarse grinding without hydrothermal treatment or fine grinding and pelleting. With only few exceptions, nutrients of the diet without SBM were more digestible (p < 0.05) resulting in a higher metabolisable energy (ME) content. Fine grinding and pelleting increased also the ME content and the nutrient digestibility with the exception of crude fibre. Higher feed intake of animals that fed diets without SBM (p < 0.01) resulted in higher average daily gain (p < 0.01). However feeding this diet, the higher digestibility was not reflected in a decreased feed-to-gain ratio (FGR), but fine grinding and pelleting reduced FGR (p < 0.001). A higher pH value and a lower DM content of caecal chymus were detected in animals that received coarsely ground feed (p < 0.05). Animals that fed finely ground and pelleted feed had higher slaughter and relative liver weights and higher blood cholesterol concentrations (p = 0.040). The urea concentrations of blood were lower (p = 0.019) after feeding diets without SBM. In conclusion, SBM imported from non-European countries can be replaced by alternative local protein sources without compromising digestibility or performances of animals. Although fine grinding and thermal treatment particularly seemed to be advantageous for digestibility and performance, the possible risk of development of stomach lesions should be considered.     

Impact of fibre intake and fibre source on digestibility,gut development,retention time and growth performance of indigenous and exotic pigs

The impact of fibre level and fibre source on digestibility, gastrointestinal tract (GIT) development, total tract mean retention time (MRT) and growth performance was studied in indigenous Mong Cai (MC) and exotic Landrace × Yorkshire (LY) pigs. The diets were based on maize, rice bran, soyabean meal, fish meal and soyabean oil, and cassava residue (CR) or brewer's grain (BG) as fibrous ingredient sources in the high-fibre diets (HF) and were fed ad libitum. A low-fibre diet (LF), containing around 200 g NDF/kg dry matter (DM), was formulated without CR and BG as feed ingredients. The HF diets (HF-CR and HF-BG) were formulated to contain around 270 g NDF/kg DM. The experiment was arranged as a 2 × 3 factorial completely randomized design with six replications, and lasted 27 days. Increased dietary fibre level resulted in a reduction (P < 0.05) in average daily gain, digestibility of organic matter (OM), CP and gross energy (GE) at the ileum and in the total tract, and in MRT, and an increase (P < 0.05) in the feed conversion ratio and in the weight of the GIT (except for small intestine and caecum). The coefficients of total tract digestibility of fibre fractions were higher in HF diets than in the LF diet, with highest values for diet HF-CR, which had a high proportion of soluble non-starch polysaccharides. MC pigs had longer MRT of digesta than LY pigs (P < 0.05), resulting in higher digestibility at the ileum and in the total tract. Across diets and breeds, the total tract apparent digestibility of OM, CP and GE was positively related (R² = 0.80 to 0.84) to the MRT of solids, whereas the MRT was negatively related to the DM intake (R² = 0.60).     

Relationship between the amino acid release kinetics of feed proteins and nitrogen balance in finishing pigs

In current nutrition requirements of swine, although the protein diets are formulated based on the ileal digestibility of protein and amino acid (AA), there is a difference in nitrogen utilisation among various protein diets, which might be related to the AA release kinetics. To evaluate the relationship between AA release kinetics of feed proteins and nitrogen balance in finishing pigs, pigs were fed diets based on casein (CAS) or corn gluten meal (CGM) at normal or low-protein concentrations, and the AA release patterns were assessed. A 2 × 2 full factorial experimental design was used. 24 pigs (Duroc × Landrace × Yorkshire) with an initial weight of 67.0 ± 1.8 kg were randomly assigned to consume a normal-protein casein-based diet (N.CAS, 10% CP), normal-protein corn gluten meal-based diet (N.CGM, 10% CP), low-protein casein-based diet (L.CAS, 8.5% CP), or low-protein corn gluten meal-based diet (L.CGM, 8.5% CP) for 14 days (n = 6 per group; pigs housed and fed separately). The low-protein diets were associated with a more rapid release of AAs in the early stages of gastric digestion than the normal-protein diets. The N.CAS and L.CAS diets were associated with a peak AA release at approximately 4 h during trypsin digestion, whereas N.CGM and L.CGM were at approximately 16 h. The N.CAS diet was associated with the least dispersed release curves and lowest synchronisation indexes, implying that it was associated with the best AA release synchronism, whereas the L.CGM diet was on the contrary. The nitrogen intake (NI), faecal nitrogen, urine nitrogen (UN), total nitrogen, net protein utilisation and apparent biological value (ABV) of protein of pigs fed the L.CAS or L.CGM diets were lower than those fed the N.CAS or N.CGM diets (P < 0.05). Notably, there was a difference in NI (P < 0.05) and trends with respect to UN and ABV (0.05 < P < 0.1), but no differences in retained nitrogen or apparent nitrogen digestibility between pigs fed the N.CAS or L.CAS diets and those fed the N.CGM or L.CGM diets. Pigs fed the N.CAS or N.CGM diets had higher serum concentrations of UN than pigs fed the L.CAS or L.CGM diets (P < 0.05), but there were no differences in serum total protein, albumin, triglyceride, glucose, alanine transaminase, or aspartate aminotransferase between the groups. In addition, there was an interaction between protein level and protein source on serum globulin (P < 0.05). Therefore, the diet with a better AA release synchronism can improve protein utilisation efficiency in finishing pigs and to reduce environmental pollution.     

Plant products affect growth and digestive efficiency of cultured Florida pompano (Trachinotus carolinus) fed compounded diets

Costs of compounded diets containing fish meal as a primary protein source can be expected to rise as fish meal prices increase in response to static supply and growing demand. Alternatives to fish meal are needed to reduce production costs in many aquaculture enterprises. Some plant proteins are potential replacements for fish meal because of their amino acid composition, lower cost and wide availability. In this study, we measured utilization of soybean meal (SBM) and soy protein concentrate (SPC) by Florida pompano fed compounded diets, to determine the efficacy of these products as fish meal replacements. We also calculated apparent digestibility coefficients (ADCs) for canola meal (CM), corn gluten meal (CGM), and distillers dried grains with solubles (DDGS), following typical methods for digestibility trials. Juvenile Florida pompano were fed fish-meal-free diets containing graded levels of SBM and SPC, and weight gain was compared to a control diet that contained SBM, SPC, and fish meal. Fish fed diets that contained 25-30 percent SBM in combination with 43-39 percent SPC had weight gain equivalent to fish fed the control diet with fish meal, while weight gain of fish fed other soy combinations was significantly less than that of the control group. Apparent crude protein digestibility of CGM was significantly higher than that of DDGS but not significantly different from CM. Apparent energy digestibility of DDGS was significantly lower than CGM but significantly higher than CM. Findings suggested that composition of the reference diet used in a digestibility trial affects the values of calculated ADCs, in addition to the chemical and physical attributes of the test ingredient.     

Effect of high fibre diets formulated with different fibrous ingredients on performance,nutrient digestibility and faecal microbiota of weaned piglets

The aim of the experiment on 180 weaned piglets (8.9 kg body weight) was to investigate the influence of high fibre diets formulated with different fibrous ingredients on performance, nutrient digestibility, diarrhoea incidence and numbers of faecal microbiota. The dietary treatments included a Control diet and five high fibre diets formulated with different fibre sources including wheat bran, soybean hulls, naked oat hulls, palm kernel expeller and bamboo fibre. The high fibre diets averaged 14.6% neutral detergent fibre with different non-starch polysaccharides (NSP) components and were fed ad libitum for 28 d. Faecal samples were collected during the last 3 d of the experiment and the apparent total tract digestibility of nutrients and fibre components were determined. Pigs fed the Control and wheat bran diets had a higher (p ≤ 0.05) average daily gain (ADG) than pigs fed the palm kernel expeller and bamboo meal diets. The reduced ADG for pigs appeared to be related to reductions in the digestibility of gross energy and dry matter, respectively. The feed-to-gain ratio was significantly higher (p ≤ 0.05) for pigs fed the fibre diets. The digestibility of NSP components was different among the treatments. The diarrhoea incidence was not affected by treatments. The abundance of faecal bifidobacteria was significantly higher (p ≤ 0.05) for pigs fed the wheat bran diet than for pigs fed the bamboo meal diet. It was concluded that the diets formulated with different fibre sources when fed to weaned piglets have different effects on pig performance, nutrient digestibility and numbers of faecal microbiota. The wheat bran diet rich in arabinoxylans enabled a better performance than the other tested diets with fibre addition.     

Efficacy of virginiamycin and a commercially-available lactobacillus probiotic in swine diets

Eight feeding trials using 708 cross-bred pigs were conducted to evaluate the addition of virginiamycin and a commercially-available lactobacillus fermention product (probiotic) to starter, grower and finisher diets based on maize and soya bean meal. Virginiamycin was added at a level of 11 mg/kg of diet, and lactobacillus probiotic at 1 g/kg in starter diets and 500 mg/kg in grower and finisher diets. In the combined analysis of four starter trials, pigs fed on diets containing virginiamycin tended to eat more and grow faster than pigs fed on the control diet, but feed efficiency was not different. Furthermore, daily gain, daily feed intake and feed efficiency were not improved by the addition of lactobacillus probiotic to starter diets. In the combined analysis of a starter—grower—finisher and a grower—finisher trial, virginiamycin supplementation did not alter overall pig performance compared with control. Pigs fed on a positive control diet containing chlortetracycline, penicillin and sulfamethazine had a nonsignificantly greater daily gain and feed intake.Daily gain for the lactobacillus probiotic-fed pigs was lower (P < 0.05) than that of the negative controls, but daily feed intake and feed efficiency were not significantly different. In three growing—finishing trials in which virginiamycin and lactobacillus probiotic were compared in a 2 × 2 factorial arrangement of treatments, daily gain and feed intakes were greater (P < 0.01) for pigs given virginiamycin. The lactobacillus probiotic did not improve daily gain, feed intake or feed efficiency. Overall, no interaction between virginiamycin and lactobacillus probiotic occurred.