Nutritional value of 15 corn gluten meals for growing pigs: chemical composition, energy content and amino acid digestibility

The objectives of this study were to determine the chemical composition, energy content and amino acid digestibility for corn gluten meals (CGM) and to develop prediction equations for estimating energy content and amino acid digestibility for growing pigs based on the chemical characteristics of these meals. The 15 CGM tested were obtained from seven Chinese companies. Experiment 1 was conducted to determine the digestible (DE) and metabolisable energy (ME) of the 15 CGM. The 18 growing barrows (38 +/- 4 kg) were assigned to three 6 x 6 Latin square designs. The 15 CGM test diets were formulated to contain 19.20% CGM, which replaced 20% of the energy supplied by corn and crystalline amino acid in the basal diet. Experiment 2 was conducted to determine the apparent (AID) and standardised (SID) ileal digestibility of the crude protein (CP) and amino acids in the 15 CGM using chromic oxide as an inert marker. The 18 growing barrows (25 +/- 2 kg) fitted with a simple T-cannula were assigned to three 6 x 6 Latin square designs. The 15 test diets contained 35% of one of the 15 CGM as the sole source of amino acids in the diet. The results showed a considerable variation in the chemical composition of CGM within and among plants. On dry matter basis, the DE and ME content of the CGM ranged from 18.8 to 21.0 MJ/kg and from 18.0 to 19.9 MJ/kg, respectively. There were no significant differences in the AID and SID for CP, arginine, lysine, glycine and proline among the 15 CGM, however, for all the other amino acids, significant differences were found for their AID and SID. With R2 values exceeding 0.50, the DE of CGM can be predicted accurately from CP and fibre content and ME from starch and fibre content. Suitable prediction equations for SID of methionine were also developed.     

Comparative digestibility of energy and ileal amino acids in yeast extract and spray-dried porcine plasma fed to pigs

Two experiments were conducted to evaluate the digestible (DE) and metabolisable energy (ME), apparent (AID) and standardised ileal digestibility (SID) of amino acids (AA) in yeast extract (YE) and spray-dried porcine plasma (SDPP). In Experiment 1, 18 barrows (25.1 ± 1.2 kg body weight [BW]) were randomly allotted to three treatments with six replicates per treatment. The DE and ME of YE was 20.64 and 19.31 MJ/kg, respectively, which were not significantly different with the DE and ME of SDPP (18.74 and 18.05 MJ/kg, respectively). In Experiment 2, six barrows (20.6 ± 2.6 kg BW) fitted with ileal T-cannulas were fed three diets in a repeated 3-period Latin square design. For Met and Glu, the AID tended to be, while the SID was significantly higher (p < 0.05), in YE than in SDPP. The AID of Cys tended to be lower in YE (p = 0.07), while the SID of Phe tended to be higher in YE than in SDPP (p = 0.06). Accordingly, YE could be a potential substitute for SDPP as a superior protein ingredient in diets for pigs in terms of the available energy and AA digestibility.     

Determination and prediction of the energy content and amino acid digestibility of peanut meals fed to growing pigs

Two experiments were conducted to determine the content of digestible energy (DE) and metabolisable energy (ME) as well as the apparent ileal digestibility (AID) and standardised ileal digestibility (SID) of amino acids in peanut meal (PNM) for growing pigs. In Experiment 1, 78 growing pigs (46.8 ± 2.6 kg) were randomly allotted to 1 of 13 diets, including a corn–soya bean meal basal diet and 12 PNM test diets. In Experiment 2, 12 growing barrows (48.7 ± 2.8 kg) were allotted to one of two 6 × 6 Latin squares. The treatments include a N-free diet and 10 PNM test diets. The results of Experiment 1 showed that the DE and ME differed (p < 0.05) among the 12 PNM samples. On a dry matter basis, the DE and ME content ranged from 14.5 to 16.4 MJ/kg (mean 15.6 MJ/kg) and from 12.7 to 15.5 MJ/kg (mean 13.9 MJ/kg), respectively. The apparent total tract digestibility (ATTD) of gross energy (GE) was 82.2%. The DE of PNM could be precisely predicted by equations including NDF combined with GE or crude protein (CP) with an R² value of 0.91 and 0.92, respectively. For the AID and SID for lysine, the results of Experiment 2 indicated variations among PNM sources ranging from 59.6% to 76.7% and 64.8% to 80.9%, respectively. However, for CP, variations for AID and SID were lower and ranged from 70.2% to 81.9% and 75.7% to 85.6%, respectively. The results indicate that the concentration of lysine was the best single predictor to estimate the digestibility of amino acids. However, further work is needed to investigate the reason for the variation in the digestibility of lysine and avoid processing procedures that are detrimental to lysine digestibility.     

Determination of energy and amino acid digestibility in growing pigs fed corn distillers' dried grains with solubles containing different lipid levels

Two experiments were conducted to estimate the digestibility of energy, nitrogen and amino acids (AA) in growing pigs fed diets containing one of five corn distillers' dried grains with solubles (DDGS), including three normal oil DDGS (NO-DDGS) and two low oil DDGS (LO-DDGS) samples. Exp. 1 was conducted to determine the digestible energy (DE) and metabolisable energy (ME) content. Six growing barrows (initial body weight [BW]: 35.1 +/- 2.2 kg) were allotted to a 6 x 6 Latin square design, with six periods and six diets. One diet was a corn soybean meal basal diet and the other five diets were based on corn, soybean meal and 28.8% DDGS. The average DE and ME values for the three NO-DDGS samples were 16.0 and 14.9 MJ/kg dry matter (DM). These values were 9 and 13% greater than the LO-DDGS values of 14.7 and 13.2 MJ/kg DM respectively. Exp. 2 was conducted to determine and compare apparent (AID) and standardised (SID) ileal digestibility for crude protein and AA in the five DDGS samples. Six growing barrows (initial BW, 32.2 +/- 1.9 kg) fitted with a simple T-cannula were allotted to a 6 x 6 Latin square design with six periods and six diets. Five of the diets were based on the five DDGS samples, and the remaining one diet was nitrogen-free diet based on cornstarch and sucrose. Titanium dioxide (0.1%) was used as inert marker. The results of the experiment showed the largest variation among the different samples in AID and SID for lysine (from 41.8 to 65.8% and 53.8 to 73.9% respectively) and threonine (from 54.3 to 73.8% and 65.2 to 79.5% respectively). Also, among the indispensable AA, the SID values for arginine, histidine, threonine and tryptophan observed in LO-DDGS were not different from the values derived from NO-DDGS. In conclusion, LO-DDGS may have decreased energy compared with NO-DDGS because of its lower fat content. However, oil removal during the production of DDGS may not affect amino acid digestibility.     

Ileal digestibility of nutrients and amino acids in low quality soybean meal sources treated with β-mannanase for growing pigs

Apparent ileal digestibility (AID) of energy, dry matter (DM), nitrogen (N) and amino acids and standardized ileal digestibility (SID) of amino acids in low quality soybean meals with different CP concentration (SBM 44% CP and SBM 48% CP) with or without 400 U β-mannanase/kg supplementation were evaluated in 20 cannulated barrows ((Landrace×Yorkshire)×Duroc) with an average BW of 25.08±3.42 kg. A N-free diet was used to determine basal endogenous losses of amino acids. The supplementation of β-mannanase improved (P<0.05) AID of DM compared with non-supplemented diet. However, enzyme supplementation did not improve (P>0.05) AID of N and energy. The type of SBM (SBM 44% CP v. SBM 48% CP) had no effect on AID of DM, N and energy. β-mannanase improved (P<0.05) AID of sum of essential amino acids, arginine, histidine, lysine, valine and glycine. The SID of lysine was higher (P<0.05) in enzyme supplemented than in non-supplemented diets. Larger AID and SID of threonine and proline (P<0.05) were observed in SBM 48% CP than in SBM 44% CP. In conclusion, the supplementation of enzyme improved AID of arginine, histidine, lysine, valine and glycine, but it did not cause marked difference in SID of these amino acids except for lysine. The low nutrient digestibility of the SBM sources used in the present experiment might have favoured the positive effect of β-mannanase supplementation.     

Determination and prediction of the digestible and metabolisable energy content of barley for growing pigs based on chemical composition

This experiment was conducted to define the sources of variation determining the energy content of barley and to develop a practical method to predict the digestible energy (DE) and metabolisable energy (ME) content of individual barley samples. The 19 barley samples used in this study were diverse varieties grown in different regions. The feeding experiment used 57 barrows (initial body weight 31.5 ± 3.2 kg) and was conducted over two consecutive periods (n = 6 per treatment) using a completely randomised design. During each period, the pigs were placed in metabolic crates for a 5-d total collection of faeces and urine following a 10-d adaptation to the diets. Among the barley samples, on dry matter (DM) basis the levels of neutral detergent fibre, acid detergent fibre (ADF), crude protein and starch ranged from 16.1% to 38.9%, 3.9% to 9.6%, 10.1% to 16.8% and 43.5% to 57.9%, respectively. The mean determined DE and ME contents amounted to 14.7 and 14.4 MJ/kg DM and varied among the samples by 1.85 MJ (13.6%) and 1.78 MJ (13.3%), respectively. The ADF fraction accounted for 73% and 76% of the total variation in the DE and ME content, respectively. It revealed that for prediction of the DE and ME contents in barley, equations had the best fit when the analysed contents of ADF, neutral detergent fibre and gross energy were used for calculation (R² = 0.92). On the basis of the developed equations, the DE and ME contents of barley of different origin can be predicted with an acceptable accuracy when used as feed for growing pigs.     

Effects of variety and storage duration on the nutrient digestibility and the digestible and metabolisable energy content of maize fed to growing pigs

The objective of this research was to determine the effects of variety and storage duration on the nutrient digestibility and the digestible (DE) and metabolisable (ME) energy content in maize when fed to growing pigs. Four maize varieties (LS1, LS2, LS3 and LS4) were hand-harvested from the same growing area in China in early October of 2012. The samples were sun dried to about 14% moisture content and then stored in the warehouse of the Fengning Pig Experiment Base at China Agricultural University for 0, 3 or 10 months. Twenty-four barrows of about 33 kg body weight were used and allotted to a completely randomised block design with four diets and six replicate pigs per diet. Pigs were individually housed in metabolic crates. The four experimental diets were formulated by mixing 96.8% of each variety of maize with 3.2% vitamins and minerals. A 5-day collection period followed a 7-day diet acclimation period. The results indicated that the DE and ME contents of maize and the apparent total tract digestibility (ATTD) of organic matter (OM), dry matter, gross energy (GE), neutral detergent fibre, acid detergent fibre (ADF), crude protein (CP) and ether extract (EE) were significantly (p < 0.05) influenced by maize variety and storage duration. With an extension of storage duration from 0 to 10 months, the DE and ME of maize and the ATTD of OM, GE, ADF, CP and EE changed in a quadratic manner (p < 0.05), and 3 months of storage exceeded 0 months of storage by 1.84%, 1.43%, 0.31%, 0.32%, 15.37%, 2.11% and 5.02%, respectively. The DE, ME of maize and the ATTD of OM, GE, ADF, CP and EE decreased by 3.67%, 6.00%, 0.97%, 1.40%, 30.54%, 3.92% and 20.93%, respectively, at 10 months of storage compared to 3 months of storage. No interaction was observed between maize variety and storage duration in DE and ME contents in maize. In conclusion, under the conditions of this study, most of the nutrient digestibility and the DE and ME contents of maize increased from 0 to 3 months and decreased from 3 to 10 months.     

Effects of combined α-galactosidase and xylanase supplementation on nutrient digestibility and growth performance in growing pigs

Two experiments were conducted to investigate the effect of combined supplementation of α-galactosidase and xylanase on nutrient digestibility and growth performance in growing pigs. Experiment 1 had a 2 × 2 Latin square design, where eight barrows (45.0 ± 0.52 kg body weight [BW]) were fitted with a simple T-cannula in the distal ileum and received a basal diet without or with supplementation of α-galactosidase (12 U/kg diet) and xylanase (15 AXC/kg diet) within two periods of 10 d. The apparent ileal digestibility (AID) and apparent total tract digestibility of nutrients, pH, viscosity of digesta and digestive enzyme activities were assessed. In Experiment 2, a total of 432 growing pigs (initial BW 44.7 ± 0.66 kg) were allocated to four treatments. Diets were based on corn and soybean meal and had a normal or reduced nutrient level (reduced by 0.42 kJ digestible energy [DE] per kg and 0.8% crude protein). Both diets were offered without or with supplementation of α-galactosidase and xylanase. The growth performance was assessed within a 43-d feeding period, where at the end, biochemical serum indices were estimated. In Experiment 1, the enzyme-supplemented diet had a greater contents of DE and DE/gross energy ratio (p < 0.05), and a higher AID of Arg, raffinose, stachyose and arabinoxylan (p < 0.05). In Experiment 2, the low nutrient level caused lower daily gain (p < 0.05), which was partially compensated by enzyme addition. Enzyme addition also increased the serum concentration of Lys (p < 0.05). Moreover, it appears that the tested enzyme supplementation could increase dietary DE, serum total amino acid concentrations and decrease serum urea nitrogen.     

Comparative digestibility of energy and nutrients in diets fed to sows and growing pigs

The objective of this research was to compare values for digestible energy (DE) and metabolisable energy (ME) and apparent total tract digestibility (ATTD) of nutrients in 11 diets fed to both growing pigs and gestating sows. Three diets were based on corn, wheat or sorghum and eight diets were based on a combination of corn and soybean meal, canola meal, conventional distillers’ dried grains with solubles, low-fat distillers’ dried grains with solubles, corn germ meal, corn bran, wheat middlings or soybean hulls. A total of 88 gestating sows (252 ± 24.2 kg BW; parity two to six) and 88 growing barrows (40 ± 4.7 kg BW) were used and randomly allotted to the 11 diets with eight replicate sows or pigs per diet. Faecal and urine samples were collected for 4 d following a 19 d adaptation period. The DE, ME and ATTD of gross energy (GE), acid detergent fibre (ADF), neutral detergent fibre (NDF) and crude protein (CP) in the 11 diets were calculated. Gestating sows had greater (p < 0.05) ATTD of GE and CP and DE values for all diets compared with growing pigs. Gestating sows also had greater (p < 0.05) ME values than growing pigs for the three grain diets and the diets containing wheat middlings and soybean hulls. No differences were observed in ATTD of ADF and NDF between gestating sows and growing pigs for any of the diets, except that gestating sows had greater (p < 0.05) ATTD of NDF than growing pigs when they were fed the four protein diets. The ATTD of GE and CP and DE values in gestating sows may be predicted by using equations generated from the values of ATTD of GE and CP and DE values obtained in growing pigs. Results of this research indicate that ATTD values of CP and GE obtained in gestating sows are greater than the values obtained in growing pigs, but values for ATTD of ADF obtained in growing pigs are not different from values in gestating sows.     

The influence of narrow-leafed lupin seed fermentation on their chemical composition and ileal digestibility and microbiota in growing pigs

The aims of this study were to provide a controlled fermentation process of blue lupin seeds (Lupinus angustifolius, cv. Neptun), monitor the changes in seed composition and determine the influence of the fermentation on the apparent ileal digestibility (AID) of crude protein (CP) and amino acids in growing pigs, compared with raw lupin seeds. The fermentation with bacteria and yeast was conducted for 24 h at 25ºC under aerobic conditions. Seed fermentation increased the contents of CP, fibre, fat and ash and most of the analysed amino acids but reduced the levels of the nitrogen-free extractives. Furthermore, fermentation decreased the contents of raffinose family oligosaccharides and phytic acids but increased the alkaloid content. The AID was estimated on three barrows (mean initial body weight 25 kg), surgically fitted with a T-cannula in the distal ileum. The pigs received three diets, each for 6 d, within three experimental periods (3 × 3 Latin Square design). The diets contained soybean meal (Group SBM), raw lupin seeds (Group RL) or fermented lupin seeds (Group FL) as solely protein sources. Fermentation had a positive impact on the AID of CP and methionine, cysteine, isoleucine, leucine, phenylalanine and valine (p < 0.05). Feeding raw or fermented lupin seeds did not affect the microbial status of the ileal digesta. Moreover, ammonia content in the caecal digesta did not differ between Groups RL and FL, although it was significantly higher than in Group SBM. It can be concluded that the fermentation process modified the chemical composition of nutrients in seeds, which can influence the digestibility and utilisation of the fermentation product in animal diets compared to raw seeds.     

Evaluation through literature data on standardized ileal digestibility and basal ileal endogenous loss of amino acids associated with barley in pigs

This meta-analysis aimed to estimate the standardized ileal digestibility (SID) and the basal ileal endogenous amino acid losses (IAA_end) in barley for growing pigs. In total, 38 different barley treatments published in 26 peer-reviewed papers were used for the meta-analysis containing information on dietary composition including amino acid (AA) contents of the assay diets, and (or) barley samples, as well as apparent ileal digestibility (AID) of AA in barley. The SID of AA was determined by either correcting AID of AA for their IAA_end or by regression analysis between the apparent ileal digestible and total dietary AA contents. The SID values obtained by correcting the AID values for their IAA_end amounted to 70%, 77%, 74% and 63% for Lys, Met, Thr and Trp, whereas those based on regression analysis method were 82%, 82%, 69% and 55%, respectively. Estimates of basal ileal endogenous loss of CP in ileal digesta varied considerably and averaged 11.84 g/kg dry matter intake (DMI), whereas IAA_end for indispensable AA ranged from 0.05 g/kg DMI for Trp to 1.90 g/kg DMI for Leu. In most cases, these estimates were considerably higher than previously reported values for IAA_end. The results of the present regression analysis indicate for most AA higher SID values compared with SID of most AA that were obtained by correcting AID values for IAA_end. In view of the observed high variations in IAA_end and the low CP content of the barley samples, estimating SID of AA based on literature data by means of the regression method may improve accuracy of SID coefficients for barley. In contrast, transformation of AID values into their corresponding SID values by using a constant correction factor for IAA_end adds an additional source of error, thereby reducing the precision in estimating SID of AA.     

Standardized ileal digestibility of amino acids in eight genotypes of barley fed to growing pigs

To determine chemical composition, physical characteristics and standardized ileal digestibility (SID) of CP and amino acids (AA) in eight current hulled barley genotypes, an experiment with growing pigs has been conducted. These genotypes included Yool, Campanile, Lomerit, Travira, Anisette, Canberra, Metaxa and Fridericus. Growing barrows with an average initial BW of 30±2 kg were surgically fitted with simple T-cannulas at the distal ileum, and allotted to an 8×9 Youden square design with eight periods of 6 days each and nine pigs. Barley was the sole dietary source of CP and AA. On average, the eight genotypes contained on as-fed basis 10.7% CP, 15.2% total non-starch polysaccharides (NSP), 17.1% NDF and 4.1% β-glucan, and had a mean test weight (TW) of 72.2 kg/hl. The SID of CP in the barley genotypes varied from 69% to 74%, and was greater (P<0.01) for genotypes Travira, Anisette and Metaxa compared to Yool and Campanile. Standardized ileal digestibility of Lys, Met and Trp (P<0.05) but not of Thr differed between genotypes. Moreover, barley genotypes differed in their standardized ileal digestible content (cSID) of CP and AA. Furthermore, SID and cSID of CP and most AA linearly decreased (P<0.05) with increasing NDF and total sugar content. Standardized ileal digestibility of CP and some AA and cSID of CP and most AA decreased linearly with increasing TW (P<0.05). Additionally, SID and cSID of CP and AA of most barley genotypes were lower when compared to tabulated values. In conclusion, a comprehensive database on chemical composition and SID of CP and AA in eight current barley genotypes has been made available. However, as present SID values are lower compared to feed tables, adjustments are required to minimize the risk of overestimating the actual protein value of barley for pigs.     

Prediction of digestible and metabolisable energy in soybean meals produced from soybeans of different origins fed to growing pigs

The objective of this experiment was to determine the digestible energy (DE) and metabolisable energy (ME) in 22 sources of soybean meal (SBM) produced from soybeans from different countries and subsequently to establish equations for predicting the DE and ME in SBM based on their chemical composition. The 22 sources of SBM were all processed in Chinese crushing plants, but the soybeans used originated from China (n = 6), the US (n = 6), Brazil (n = 7) or Argentina (n = 3). The basal diet was a corn-based diet and 22 additional diets were formulated by mixing corn and 24.3% of each source of SBM. The average DE and ME in SBM from China, the US, Brazil and Argentina were 15.73, 15.93, 15.64 and 15.90 MJ/kg and 15.10, 15.31, 14.97 and 15.42 MJ/kg, respectively, and no differences among countries were observed. From a stepwise regression analysis, a series of DE and ME prediction equations were generated. The best-fit equations for SBM were DE = 38.44–0.43 crude fibre ?0.98 gross energy +0.11 acid detergent fibre (R² = 0.67, p < 0.01) and ME = 2.74 + 0.97 DE ?0.06 crude protein (R² = 0.79, p < 0.01). In conclusion, there were no differences in the DE and ME of SBM among the different soybean sources used in this experiment. The DE and ME of SBM of different origin can be predicted based on their chemical composition when fed to growing pigs.     

Estimating the requirement of dietary crude protein for growing blue-breasted quail (Excalfactoria chinensis)

Two experiments were conducted to investigate the requirement for dietary crude protein (CP) in growing blue-breasted quail (BBQ). In Experiment 1, 300 1-day-old quails were randomly assigned to 10 groups according to a 2×5 factorial arrangement of treatments with two metabolisable energy (ME) levels (12.13 and 13.39 MJ/kg) and five CP concentrations (160, 190, 220, 250 and 280 g/kg) for 8 weeks. In Experiment 2, 300 1-day-old quails were subjected to a different factorial arrangement of treatments with two ME levels (11.51 and 12.13 MJ/kg) and five CP concentrations (210, 220, 230, 240 and 250 g/kg) for 28 days. Experiment 1 revealed that an interaction existed in weight gain between ME and CP levels in weeks 1 to 4. In both ME groups, quails receiving CP of 160 g/kg showed the least weight gains (P<0.05). No differences (P>0.05) existed in weight gain between the ME groups in which quails ingested CP of 250 and 280 g/kg, whereas quails consuming CP of 220 g/kg with an ME of 13.39 MJ/kg had smaller weight gain than did those ingesting higher CP concentrations (P<0.05). Of main effects for weeks 1-4, quails treated with an ME of 12.13 MJ/kg consumed more feed than did those receiving another ME level, whereas quails in both ME treatments showed similar feed efficiencies. For weeks 5 to 8, no difference (P>0.05) in weight gain, feed intake and feed efficiency was seen regardless of ME levels, and no interaction existed between ME and CP levels. In Experiment 2, the best weight gain and feed efficiency were achieved when the dietary CP concentration was more than 210 g/kg, and quails treated with 11.51 MJ/kg showed better weight gain and feed efficiency (P<0.05) than did those that received 12.13 MJ/kg. Furthermore, the weight gains and protein intakes on the basis of per MJ from the two experiments were pooled together to estimate the protein intake necessary for the best growth performance by two mathematic models; they were then converted to dietary CP concentrations of 204 (minimum) and 233 g/kg (maximum) when ME was 11.51 MJ/kg. In conclusion, BBQ will achieve good growth performance with dietary CP of more than 204 g/kg on the basis of an ME of 11.51 MJ/kg in weeks 1 to 4.     

Protein and energy value of vinasse for pigs

A vinasse, originating as the condensed molasses residue from the microbial production of citric acid, was chemically analyzed and given to growing pigs to determine its protein and energy value. It contained, per kg dry matter (62.6%), 185 g crude protein, 538 g N-free extracts, 48 g total sugar, 277 g ash and 12.8 MJ gross energy. Ammonia, betaine and amino acids (about half glutamic acid) accounted for 3.5, 9.1 and 28.6%, respectively, of the crude-protein N. In a 25-day balance trial with the final 10 days as collection period, ten pigs initially weighing 33 kg were pair-fed daily an average of about 1 kg of dry matter of either a basal diet (95% ground barley plus 5% cellulose) or of a mixed diet composed of, on dry basis, 77% basal diet plus 23% vinasse. Partial digestibility of components in the vinasse was: organic matter, 52%; crude protein, 45%; N-free extract, 58%; ash, 83%; and gross energy, 42%. Average daily gain and N retention were not different between dietary groups. The vinasse contained, per kg dry matter, 5.40 MJ DE and 3.61 MJ ME compared with 14.96 MJ DE and 14.48 MJ ME for the dry basal diet. The conclusion is that this vinasse, according to its low protein and energy value, can provide only a small percentage of the daily ration for pigs.     

Determination of Apparent Ileal Amino Acid Digestibility in Rapeseed Meal and Cake Processed at Different Temperatures Using the Direct and Difference Method with Growing Pigs

Studies were conducted with ten barrows, average initial body weight 34.5 ± 2.1kg, fitted with a T-cannula at the distal ileum, to study the accuracy of determination of the apparent ileal digestibility (AID) values of crude protein (CP) and amino acids (AA) in rapeseed meal and cake and the effects of processing, using the difference method. Five corn starch-based diets in the studies were formulated to contain 17.7% CP and based on soybean meal, prepress-extraction rapeseed meal, prepress-extraction rapeseed meal plus soybean meal, high-temperature press rapeseed cake plus soybean meal, or low-temperature press rapeseed cake plus soybean meal as the sole source of dietary protein. The design was an incomplete Latin Square involving two three-week periods and five-treatments. It was found that the AID values of CP and most AA determined with the difference or direct method were significantly lower in rapeseed meal or cakes than soybean meal. The AID values of CP and most AA in prepress-extraction rapeseed meal, high-temperature press or low-temperature cakes determined with the difference method were no difference from those in prepress-extraction rapeseed meal determined with the direct method. The AID values of CP and AA in rapeseed meal and cake determined with the difference method were accurate, when the contribution of CP and AA from rapeseed was more than 50%. The AID values of CP and AA (especially lysine) were lower in the high-temperature press rapeseed cake than in the low-temperature press cake or the prepress-extraction meal.     

Nutrient and energy balance,and amino acid digestibility in weaned piglets fed wheat bran and an exogenous enzyme combination

The digestive system of the weaned piglets can be affected by the type of ingredients present in the diet, and a high fibre content in diets can limit the use of other nutrients and energy. The study was conducted to determine the effects of multicarbohydrase (MC) and phytase (Phy) supplementation on the nutritive value of wheat bran (WB) in weaned piglets. Multicarbohydrase preparation had 700 U α-galactosidase, 2200 U galactomannanase, 3000 U xylanase and 22 000 U β-glucanase per kilogram of diet, and Phy had 500 phytase units – FTU/kg of diet. Twenty-five weaned piglets (6.1 ± 0.63 kg) at 21 days old were fed five diets in a completely randomised experimental design with a 2 × 2 + 1 (0 and 200 mg/kg MC; 0 and 50 mg/kg Phy; and basal diet – BD) factorial arrangement used to determine treatment effects. An additional group of piglets was fed a corn-basal diet during apparent digestibility of nutrients, and fed a 5% casein-corn starch basal diet during apparent and standardised ileal digestibility (SID) of amino acid evaluations. Piglets were individually caged until 38 days old, when Ileal digesta was collected at slaughter. Test diets were made by mixing the basal diets and WB 7 : 3 (w/w), with or without MC, Phy or the combination. There was an interaction trend (P = 0.07) between MC and Phy in the balance of ash, digestible energy (DE) and metabolisable energy (ME). Effects of MC (P < 0.01) on DM, N retention, DE and ME, as well as an effect of Phy (P < 0.05) on ash, DE and ME and a trend in protein digestibility (P = 0.07) also was observed. The enzyme combination showed effect (P < 0.05) on SID of Lys, Pro and Ser; as a trend (P < 0.07) on His, Thr and Val. Isolated, MC also suggested improving (P < 0.07) on SID of His, Lys, Ala (P < 0.05), while Phy improved (P < 0.06) SID of Leu, Lys, Met (P < 0.01), Thr, Val, Ala (P < 0.01), Pro and Ser (P < 0.05). The MC carbohydrate complex was characterised as a viable alternative to increase the apparent nutrients digestibility and SID of amino acids when WB was used in the diet of young pigs and, when combined with Phy, suggested an additive effect on the apparent use of energy.     

Prediction of the metabolisable energy content of forages and mixed diets for horses: validation and comparison of two evaluation systems

The metabolisable energy (ME) content of feeds is a better estimate of their ‘true’ energy value than their digestible energy (DE) content, because ME takes account of the gross energy of methane (GEgas) and the gross energy of urine (GEurine) losses. The accuracy and precision of the Gesellschaft für Ernährungsphysiologie (GfE) and Institut National de la Recherche Agronomique (INRA) systems for predicting the DE and ME contents of diets for horses were compared using the results of a study comprising 15 mixed diets. The INRA system was more accurate than the GfE system for predicting DE, GEurine and ME: the biases between the predicted and the measured values were − 0.26 vs –0.46 MJ/kg DM for DE (P < 0.05), − 0.03 vs 0.13 MJ/kg DM for GEurine (P < 0.05) and − 0.09 vs –0.62 MJ/kg DM for ME (P < 0.05). The biases for GEgas were not significantly different (P > 0.05) between systems. In addition, a study was carried out with 24 forages to compare the ME value of permanent meadow and lucerne hays predicted with the GfE and the INRA systems. The INRA system gave higher prediction values of DE than the GfE system (P < 0.001) and lower estimates of GEgas (0.34 vs 0.63 MJ/kg DM for permanent meadow hays and 0.38 vs 0.63 MJ/kg DM for lucerne hays) (P < 0.001) and GEurine (0.85 vs 0.93 MJ/kg DM for grassland hays and 1.08 vs 1.37 MJ/kg DM for lucerne hays) (P < 0.001). The INRA system thus gave higher estimates of ME (7.57 vs 6.77 MJ/kg DM for permanent meadow hays and 8.80 vs 6.46 MJ/kg DM for lucerne hays, P < 0.001) in agreement with the results obtained with mixed diets. The ME values of permanent meadow hays and legume hays should therefore be predicted separately using specific equations as previously established for the DE value.     

Effect of niacin supplementation on digestibility,nitrogen utilisation and milk and blood variables in lactating dairy cows fed a diet with a negative rumen nitrogen balance

The aim of the present experiment was to determine if a niacin supplementation of 6 g/d to lactating dairy cow diets can compensate negative effects of a rumen nitrogen balance (RNB) deficit. A total of nine ruminally and duodenally fistulated lactating multiparous German Holstein cows were successively assigned to one of three diets consisting of 10 kg maize silage (dry matter [DM] basis) and7 kg DM concentrate: Diet RNB– (n = 6) with energy and utilisable crude protein at the duodenum (uCP) according to the average requirement of the animals but with a negative RNB (–0.41 g N/MJ metabolisable energy [ME]); Diet RNB0 (n = 7) with energy, uCP and a RNB (0.08 g N/MJ ME) according to the average requirement of the animals and, finally, Diet NA (n = 5), which was the same diet as RNB–, but supplemented with 6 g niacin/d. Samples of milk were taken on two consecutive days, blood samples were taken on one day pre- and post-feeding and faeces and urine were collected completely over five consecutive days. The negative RNB reduced milk and blood urea content and apparent total tract digestibility of DM, organic matter (OM) and neutral detergent fibre (NDF). Also N excretion with urine, the total N excreted with urine and faeces and the N balance were reduced when the RNB was negative. Supplementation of niacin elevated plasma glucose concentration after feeding and the N balance increased. Supplementing the diet with a negative RNB with niacin led to a more efficient use of dietary N thereby avoiding the negative effects of the negative RNB on the digestibility of DM, OM and NDF.