Prediction of protein and amino acid composition and digestibility in individual feedstuffs and mixed diets for pigs using near-infrared spectroscopy

Knowledge of the amounts and digestibility of amino acids in pig feedstuffs is essential for calculating the appropriate inclusion level in a complete diet. Wet chemical analysis and in vivo digestibility trials are time-consuming and costly and cannot be used for routine assessment. Near-infrared spectroscopy (NIRS) offers a rapid, cost effective and environmentally friendly method for evaluating feedstuffs. Calibrations models were developed using NIRS to predict the content of crude protein and 18 amino acids from a wide range of feedstuffs used in pig production (n = 607). The samples ranged from single feed ingredients (containing amino acids from 0.3 to 129.8 g/kg of dry matter) to feed mixtures (containing amino acids from 1.2 to 53.2 g/kg of dry matter). The predictive ability of the calibrations was tested with an independent dataset (n = 150) and with cross-validation. Furthermore, we compare these calibrations with calibrations developed on more narrowly defined groups of samples and with predictions from regression analysis of crude protein. The models were able to predict the concentrations of crude protein and 18 amino acids with good levels of precision and high coefficients of determination for calibration (RSQ ^CAL) from 0.91 to 0.99 and validation (RSQ^VAL) from 0.87 to 0.97. Calibration models were able to predict all amino acids except tryptophan and valine with greater accuracy than those from protein regression. We also developed calibration models to predict the apparent ileal and total tract digestibility of protein and amino acids. With the exception of tryptophan, RSQ values (>0.7) and standard error of cross validation (SECV) values (<5%) were obtained for the digestibility of most of the amino acids. In conclusion, NIRS can be used to predict crude protein and amino acid concentrations from a wide range of single ingredients and feed mixtures used for pig diets without separate models for each feedstuff. The digestibility of protein and amino acids can be predicted with an acceptable accuracy to be useful in formulating pig diets.     

Ileal digestibility of protein and amino acids from canola meal in weaned piglets and growing pigs

Two experiments were conducted to measure the apparent ileal digestibility coefficients (AID) of protein and amino acids from canola meal (CM) and a pelleted canola meal (PCM) and their effect on specific activity (SA) of pancreatic proteases in weaned piglets and growing pigs. In experiment one, 24 piglets weaned at 17 days and weighing 5.5 kg were used. Treatments were a reference diet with 200 g of crude protein (CP) kg^− 1 elaborated with casein (C) as the sole protein source, a diet containing C–CM and a diet containing C–PCM. These diets were obtained using the reference diet plus 100 g kg^− 1 of CM or PCM that substituted an isoproteic mixture of casein and maize starch from reference diet, so that the AID coefficients for their protein and amino acids could be calculated by difference. In experiment two, nine castrated pigs weighing 39.5 kg were used. Treatments were a reference diet with 160 g of CP kg^− 1 elaborated with casein (C) as the sole protein source, diet C–CM and diet C–PCM. These diets were obtained using the reference diet plus 300 g kg^− 1 of CM or PCM that substituted an isoproteic mixture of casein and maize starch from reference diet. In piglets, the AID coefficients for casein were highest (P < 0.05), those of PCM were intermediate, and those of CM were the lowest. In older pigs, the AID coefficients for casein were highest, and those of CM and PCM were similar (P > 0.05). The SAs of chymotrypsin, trypsin and carboxypeptidases A and B were lower in piglets than in heavier pigs. Moreover, the SAs of trypsin, chymotrypsin, and carboxypeptidase B were lower (P > 0.05) in animals fed casein. The results showed in piglets that whereas CM was less digestible, pelleted canola meal improved protein and amino acid ileal digestibility, resulting in similar AID coefficients to those of growing pigs.     

Acanthopanax senticosus extract as a dietary additive enhances the apparent ileal digestibility of amino acids in weaned piglets

The present study was conducted to determine the effects of Acanthopanax senticosus (AS) extract as a dietary additive on serum contents and apparent ileal digestibility (AID) of amino acids (AA) in weaned piglets. In Exp. 1, 60 piglets with an average body weight (BW) of 5.64 kg were randomly assigned into 3 treatment groups who received maize-soybean-based diets supplemented with 0 or 1 g/kg of AS extract or 0.2 g/kg of colistin (n = 20 in each group). Blood samples were randomly collected from 5 piglets per group on days 7, 14 and 28 after the initiation of supplementation to determine the serum contents of free AA. In Exp. 2, 12 barrows with an average initial BW of 7.64 kg were also randomly assigned into 3 dietary treatment groups after being surgically fitted with a simple T-cannula at the terminal ileum. Samples of terminal ileal digesta were collected on day 7 for analysis of the AID of AA. The data showed that the serum contents and AID of most AA in the AS extract-supplemented group gradually increased by 15.3–80.8% and 4.1–30.8%, respectively, as the experiment proceeded in comparison with the colistin-supplemented group and/or control group. In conclusion, these findings indicated that AS extract could enhance the digestion and absorption of AA, which may be a potential mechanism of growth promotion.     

In vitro antagonistic activities of Lactobacillus spp. against Brachyspira hyodysenteriae and Brachyspira pilosicoli

The sensitivity of Brachyspira hyodysenteriae and Brachyspira pilosicoli, respectively the causative agents of Swine Dysentery and Porcine Intestinal Spirochaetosis to two probiotic Lactobacillus strains, L. rhamnosus CNCM-I-3698 and L. farciminis CNCM-I-3699 was studied through viability, motility and coaggregation assays. The cell-free supernatant of these lactobacilli contains lactic acid, that is stressful for Brachyspira (leading to the formation of spherical bodies), and lethal. It was demonstrated for the first time the in vitro coaggregation properties of two probiotic Lactobacillus strains (active or heat-treated) with two pathogenic strains of Brachyspira, leading to (1) trapping of spirochaetal cells in a physical network as demonstrated by SEM; (2) inhibition of the motility of Brachyspira. Such in vitro studies should encourage in vivo studies in animal model to evaluate the potential of the use of probiotic lactobacilli through a feeding strategy for the prevention of B. hyodysenteriae and B. pilosicoli.     

The effect of grinding and pelleting of wheat and maize on amino acids true ileal digestibility and endogenous losses in growing pigs

Two experiments were performed in order to test the effects of grinding and pelleting wheat (experiment 1) or maize (experiment 2) on amino acids (AA) standardized (SID) and true (TID) ileal digestibility. Basal ileal endogenous losses (IEL), used to calculate SID from apparent digestibility, were determined by feeding a protein-free diet. Total IEL required to calculate TID were estimated as the difference between total and dietary losses determined according to the isotope dilution technique using ¹⁵N-labeled crops. Wheat and maize were ground to compare two different mean particle sizes (d₅₀ 500 μm and 1000 μm). Then, a fraction of the 500-μm mash was further pelleted through two dies of different thicknesses (16 vs. 20 mm for wheat and 16 vs. 24 mm for maize), holes diameter 4 mm in both cases. Cereals were incorporated in 4 isoproteic diets either in mash form (fine vs. coarse mash) or in pelleted form (thin vs. thick die). In experiment 1, wheat was associated with rapeseed meal diets, while in experiment 2, maize was associated with soybean meal. The reduction of wheat particle size affected neither AA SID nor TID. In contrast, the pelleting treatment significantly improved protein and most AA SID and TID. In addition, total IEL of protein and several AA were significantly reduced when the thicker die was used. Numeric improvements of protein and AA SID were observed with reduction of maize particle size and this was associated with a significant decrease in total IEL so that TID was not modified. Further improvements of AA SID and TID occurred with pelleting of maize, without significant effect on IEL regardless of die thickness.     

Effects of two phytases on the ileal apparent digestibility of minerals and amino acids in ileo-rectal anastomosed pigs fed on a maize–rapeseed meal diet

Phosphorus (P) from plant-derived feedstuffs is mainly in the form of phytic-P, which has a very low bioavailability in monogastric animals. The non-absorbed phytic-P may contribute to P pollution, reduce mineral bioavailability and might reduce protein digestibility. The aim of this study was to evaluate the effects of the recommended levels of Ronozyme® P CT 5000 (750 U/kg — RP) and Natuphos® 5000 (500 U/kg — Nat) on the ileal apparent digestibility of total P, phytates (Phy), calcium (Ca), total nitrogen (N), energy, and amino acids (AA) in 60-day-old ileo-rectal anastomosed pigs. In a double Latin square design they were fed ad libitum either a maize–rapeseed meal based diet or this diet supplemented with RP or with Nat. RP and Nat increased the digestibility of P by 148% and 162%, of Phy by 84% and 76%, and of Ca by 44% and 50%, respectively. The total N digestibility was increased by 4% with RP (P < 0.01) and by 1% with Nat. A numerically increase of the digestibility of most of the AA was observed for Nat and of all AA for RP. Threonine digestibility was significantly increased by RP (P < 0.05). The results of this study indicate that phytases are able to increase the availability of proteins.     

Metabolizable energy,nitrogen balance,and ileal digestibility of amino acids in quality protein maize for pigs

Background：To compare the nutritional value and digestibility of five quality protein maize（QPM） hybrids to that of white and yellow maize,two experiments were carried out in growing pigs.In experiment 1,the energy metabolizability and the nitrogen balance of growing pigs fed one of five QPM hybrid diets were compared against those of pigs fed white or yellow maize.In experiment 2,the apparent and standardized ileal digestibility（AID and SID,respectively） of proteins and amino acids from the five QPM hybrids were compared against those obtained from pigs fed white and yellow maize.In both experiments,the comparisons were conducted using contrasts.Results：The dry matter and nitrogen intakes were higher in the pigs fed the QPM hybrids（P 〈 0.05） than in the pigs fed white or yellow maize.Energy digestibility（P 〈 0.001） and metabolizability（P 〈 0.01） were higher in the pigs fed the white and yellow maize diets than in those fed the QPM diets.The AID of lysine was higher（P〈 0.01） in the QPM diets than in the white and yellow maize.The AIDs of leucine,isoleucine,valine,phenylalanine,and methionine were lower in the QPM diets than those of maize（white and yellow）（all P 〈 0.05）.Maize（white and yellow） had greater SIDs of leucine,isoleucine,valine,phenylalanine,glutamic acid,serine,alanine,tyrosine,and proline（P 〈 0.05）.Conclusions：Based on these results,it was concluded that QPM had a lower metabolizable energy content and a higher amount of digestible lysine than normal maize.     

Definition of apparent, true, and standardized ileal digestibility of amino acids in pigs

Measures of ileal digestibility (ID) are used routinely as estimates of amino acid (AA) bio-availability in pig feed ingredients. Values for ID may be expressed as apparent (AID), standardized (SID), or true (TID). Values for AID are calculated by deducting the total ileal outflow of AA (the sum of endogenous losses (IAA_end) and non-digested dietary AA) from dietary AA intake. The IAA_end may be separated into basal losses, which are not influenced by feed ingredient composition, and specific losses induced by feed ingredient characteristics such as anti-nutritional factors and dietary fiber. If the AID values are corrected for total IAA_end, then values for TID are calculated. Lack of additivity of AID values in feed formulation may be overcome by correcting AID values for basal IAA_end only, which yields SID values. Until reliable procedures for the routine measurement of specific IAA_end become available, it is suggested that SID values are used for feed formulation. It is advisable that basal IAA_end are measured in digestibility experiments and that these losses are reported with SID values.     

Metabolizable energy,nitrogen balance,and ileal digestibility of amino acids in quality protein maize for pigs

Background

To compare the nutritional value and digestibility of five quality protein maize (QPM) hybrids to that of white and yellow maize, two experiments were carried out in growing pigs. In experiment 1, the energy metabolizability and the nitrogen balance of growing pigs fed one of five QPM hybrid diets were compared against those of pigs fed white or yellow maize. In experiment 2, the apparent and standardized ileal digestibility (AID and SID, respectively) of proteins and amino acids from the five QPM hybrids were compared against those obtained from pigs fed white and yellow maize. In both experiments, the comparisons were conducted using contrasts.

Results

The dry matter and nitrogen intakes were higher in the pigs fed the QPM hybrids (P < 0.05) than in the pigs fed white or yellow maize. Energy digestibility (P < 0.001) and metabolizability (P < 0.01) were higher in the pigs fed the white and yellow maize diets than in those fed the QPM diets. The AID of lysine was higher (P < 0.01) in the QPM diets than in the white and yellow maize. The AIDs of leucine, isoleucine, valine, phenylalanine, and methionine were lower in the QPM diets than those of maize (white and yellow) (all P < 0.05). Maize (white and yellow) had greater SIDs of leucine, isoleucine, valine, phenylalanine, glutamic acid, serine, alanine, tyrosine, and proline (P < 0.05).

Conclusions

Based on these results, it was concluded that QPM had a lower metabolizable energy content and a higher amount of digestible lysine than normal maize.     

Screening of Aflatoxins and Zearalenone in feedstuffs and complete feeds for pigs in Southern Vietnam

A survey ofaflatoxins and zearalenone (ZEA) in 120 samples, including cassava chip (12), maize (12), rice bran (24), broken rice (24), and complete feeds for growing pigs (24) and sows (24) was carried out in southern Vietnam. Aflatoxin B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) were determined by an HPLC method using an immunoaffinity column for clean-up. Zearalenone was analysed by Enzyme-Linked Immunosorbent Assay (ELISA) AgraQuant. High incidences of aflatoxins and ZEA in feedstuffs and pig feeds (83.3%-100%) were detected. Aflatoxins and ZEA were detected in all commodities analyzed. Aflatoxin B1 was found in 100, 92, 92, 83, 100 and 96%, respectively, of samples of cassava chip, maize, rice bran, broken rice, and complete feeds for growing pigs and sows, with mean concentrations of 0.86, 77.5, 1.3, 1.6, 4.7 and 7.5 microg/kg, respectively. AFB2 and AFG1 were found in low concentrations and co-occurred with AFB1 in all samples where they were found. ZEA was detected in 8%, 33%, 36%, 21%, 67% and 67%, respectively, of the samples of cassava chip, maize, rice bran, broken rice, and complete feeds for growing pigs and sows, with average concentrations of 10.0, 163.5, 83.1, 31.4, 86.0 and 101.4 microg/kg, respectively. The high incidence of mycotoxins found in feedstuffs highlights the need for periodic monitoring and prevention ofmycotoxins, not only in feeds, but also in food for human consumption.     

Apparent digestibility of nitrogen and amino acids in protein feedstuffs by growing pigs

Eight digestion trials were conducted with pigs fitted with ileal T-cannulas to determine the apparent digestibilities of N and amino acids in common protein feedstuffs. Trial-to-trial variation was minimal as determined by the variation in digestibilities for soybean meal, which was evaluated in each trial. Apparent digestibilities varied widely; ileal N digestibility ranged from 88 to 63%, and ileal lysine digestibility ranged from 93 to 40%. In general, ring-dried blood meal, corn gluten meal, Menhaden fish meal, poultry-by-product meal and extruded whole soybeans were the most digestible, followed by canola meal, sunflower meal, peanut meal and meat and bone meal. Cottonseed meal and feather meal were the least digestible. Mean values for each feedstuff agree well with published data. Variation in digestibilities among samples of the same feedstuff was greater for the meat and bone meals. Regression of ileal essential amino acid digestibilities on ileal and fecal N digestibility indicated that amino acid digestibilities can be predicted more precisely from ileal N digestibility than from fecal N digestibility. However, neither ileal nor fecal N digestibility could be used with a high degree of certainty to predict ileal amino acid digestibilities.     

Influence of guanidination on apparent ileal digestibility of amino acids in pigs fed diets with soybean meal, rapeseed meal or peas as a protein source

The objective of this study was to determine the effect of guanidination, the conversion of dietary lysine to homoarginine, on the apparent ileal digestibilities (AID) of amino acids (AA) from 3 protein sources in diets for pigs. Six barrows, initial body weight of 18 ± 1.5 kg, fitted with a simple T-cannula at the distal ileum, were fed one of three corn starch-based diets that contained 18% crude protein (CP) from soybean meal, rapeseed meal or peas for an experimental period of 10 d according to a repeated 3 × 3 Latin square design. On d 9 of each experimental period, the pigs were fed one meal of the guanidinated test meals, which corresponded to their respective diets. In the test meals, 50% of the protein source in each diet was replaced, on an equal weight basis, with a guanidinated source. Guanidination increased the content of CP by 190, 116 and 28 g kg^− 1 for soybean meal, rapeseed meal and peas, respectively. With the exception of lysine, the AID of CP and AA were 2.2 to 8.2 percentage units (pu) higher in the test meal than in the soybean meal diet. Other than arginine and isoleucine, the differences were significant (P < 0.05) for all indispensable AA. With the exception of lysine, the AID of CP and AA were 3.8 to 11.9 pu higher in the test meal than in the diet with peas. The differences were significant (P < 0.05) for all indispensable AA. Other than lysine, glycine and proline, the AID of CP and AA were slightly higher, 0.1 to 4.3 pu, in the test meal than in the rapeseed meal diet. Of the indispensable AA, the differences were significant (P < 0.05) for arginine, leucine and phenylalanine. The AID of lysine was 10.9 pu lower (P < 0.05) in the test meal than in the rapeseed meal diet, 61.5 vs. 72.4%, indicating that guanidination of rapeseed meal was not uniform and random. The increase in the AID of CP and AA after guanidination may result from solubilisation of protein and degradation of antinutritional factors such as fiber, trypsin inhibitors and tannins.     

In vitro degradation of phytate and lower inositol phosphates in soaked diets and feedstuffs

A series of in vitro experiments simulating liquid feeding were performed to evaluate the effect of microbial phytase addition, heat-treatment and soaking time on degradation of phytate and lower inositol phosphates when soaking compound wheat/soybean meal diets or the single feedstuffs wheat or soybean meal. The effect of phytase addition on phytate degradation was greatest in soybean meal, almost intermediate for wheat/soybean meal diets and not detectable in wheat, which might be due to a better accessibility to phytate in soybean meal compared with wheat. Heat-treatment seemed to enhance the accessibility between phytase and phytate, whereby phytate degradation was stimulated. Additionally, it was shown that wheat phytase is able to stimulate degradation of phytate in soybean meal. Independent of treatment, the amount of IP₅–IP₂ was extremely small in relation to phytate in both wheat and soybean meal, indicating that when one phosphate group is removed from the phytate complex, degradation of IP₅–IP₂ is completed. Consequently, it is anticipated that liquid feeding might result in a higher digestibility of plant P compared with dry feeding of pigs.     

精油对生长猪蛋白质和氨基酸等回肠末端表观消化率的影响

试验旨在通过采用T型瘘管法,研究精油对生长猪蛋白质和氨基酸等回肠末端表观消化率的影响。试验选用6头(杜×长×大)去势公猪([28.6±1.3)kg],采用3×3双拉丁方试验设计,分别饲喂正对照日粮:玉米-豆粕型基础日粮+抗生素;负对照日粮:无抗基础日粮;精油组日粮:负对照+0.01%精油。每个试验期为7 d,前5 d为适应期,后2 d为食糜收集期。结果表明,在日粮中添加精油可提高(P<0.05)蛋白质、能量、精氨酸、赖氨酸、亮氨酸、色氨酸、蛋氨酸、丙氨酸、总必需氨基酸、总氨基酸的回肠末端表观消化率,并有提高干物质、苏氨酸、天冬氨酸、丝氨酸和酪氨酸表观消化率的趋势(P<0.10)。在日粮中添加0.01%的精油可提高生长猪蛋白质、能量、总必需氨基酸和总氨基酸的回肠末端表观消化率,并有提高干物质表观消化率的趋势。     

First in vitro isolation of Besnoitia besnoiti from chronically infected cattle in Germany

Besnoitia besnoiti was in vitro isolated during the first recorded outbreak of bovine besnoitiosis in Germany. Molecular characterization of the new isolate, named Bb-GER1, revealed almost 100% identity with other B. besnoiti isolates obtained in Portugal, Spain, Israel or South Africa, when partial sequences of the 18S ribosomal RNA gene, of the internal transcribed spacer 1 and of the 5.8S RNA gene were compared. Cystozoites obtained from skin tissue of one bull were infectious for γ-interferon knockout (GKO) mice by intraperitoneal (ip) inoculation. Tachyzoites were detected in the peritoneal cavity, spleen, liver and lung of the mice 5 days post-infection. The parasite could be maintained in GKO mice by ip inoculation for at least 5 passages. Peritoneal washings containing tachyzoites were obtained from infected mice and used to infect five cell lines (Vero, MARC-145, NA42/13, BHK₂₁, KH-R). The best growth of tachyzoites was observed in BHK₂₁ cells, but replication occurred to a smaller extent also in MARC-145, NA42/13 and KH-R cells. Subsequent comparative analyses revealed that after direct infection of these cell lines with cystozoites derived from bovine skin, the growth was best in NA42/13 cells. Considerable replication was also observed in the BHK₂₁ and KH-R cell lines. Our observations on the growth characteristics of Bb-GER1 partially contrast those for other isolates. The preferential growth in particular cell lines may be characteristic for particular B. besnoiti isolates. A potential association between growth properties and differences in virulence remains to be established. This is the first in vitro isolation of B. besnoiti from cattle in Germany.     

Apparent and standardised ileal digestibility of amino acids in wheat,triticale and barley for broiler chickens at two different ages

ABSTRACT

1. The influence of the age of broiler chickens on ileal amino acid (AA) digestibilities in three cereals was examined. The digestibility estimates, including both apparent (AID) and standardised (SID) coefficients, for wheat, triticale and barley samples were determined using 14 and 28 d old broilers of mixed sex, fed diets containing the test grains as the only source of protein.

2. Each assay diet was offered to five replicate cages of 14 and eight birds respectively, for the 14 and 28 day samplings. On both sampling days, the contents from the lower half of the ileum were collected for determination of the AID coefficients. The SID coefficients were calculated using ileal endogenous amino acid (EAA) losses previously determined from birds fed an N-free diet.

3. The average AID for essential AA (EAA) in triticale and barley were significantly higher at 28 day compared to those at 14 days. In contrast, the magnitude of AID coefficients of AA in wheat was found to be in larger in the younger chickens.

4. Correction of AID for EAA losses increased the values of digestibility coefficients by an average of about 7%. The SID values of AA in wheat was not influenced by the age of broilers. The SID of most AA in triticale, and of all the AA in barley, were higher in 28-day-old chickens compared with their 14-day-old counterparts. The results suggested that the SID coefficients of EAA in wheat determined at day 28 could be applied to feed formulations for 14-day-old broilers, but in the case of triticale and barley, the values obtained in older chickens were not applicable in younger birds and vice versa.     

In vitro antiviral activity of chestnut and quebracho woods extracts against avian reovirus and metapneumovirus

Field evidences have suggested that a natural extract, containing tannins, could be effective against poultry enteric viral infections. Moreover previous studies have shown that vegetable tannins can have antiviral activity against human viruses. Based on this knowledge three different Chestnut (Castanea spp.) wood extracts and one Quebracho (Schinopsis spp.) wood extract, all containing tannins and currently used in the animal feed industry, were tested for in vitro antiviral activity against avian reovirus (ARV) and avian metapneumovirus (AMPV). The MTT assay was used to evaluate the 50% cytotoxic compounds concentration (CC₅₀) on Vero cells. The antiviral properties were tested before and after the adsorption of the viruses to Vero cells. Antiviral activities were expressed as IC₅₀ (concentration required to inhibit 50% of viral cytopathic effect). CC₅₀s of tested compounds were >200 μg/ml. All compounds had an extracellular antiviral effect against both ARV and AMPV with IC₅₀ values ranging from 25 to 66 μg/ml. Quebracho extract had also evident intracellular anti-ARV activity (IC₅₀ 24 μg/ml). These preliminary results suggest that the examined vegetable extracts might be good candidates in the control of some avian virus infections. Nevertheless further in vivo experiments are required to confirm these findings.     

Apparent and standardized ileal digestibility of amino acids in diverse barley cultivars fed to growing pigs

The objectives of this study were to determine the chemical composition, ileal amino acid (AA) digestibility of barley varieties and to develop equations to predict the AA digestibility based on the chemical characteristics of individual barley. A wide selection of nine barley varieties in the main growing regions of China was used in the experiment. Ten crossbred pigs (30.9 ± 1.8 kg) were allotted to a 6 × 10 Youden Square. The treatments included a nitrogen‐free diet and nine barley test diets. Considerable variation was observed in the content of neutral detergent fiber, acid detergent fiber, crude protein (CP) and all AAs among the barley samples. The standardized ileal digestibility (SID) of indispensable AAs with the exception of arginine, phenylalanine and threonine were different (P < 0.05) among the nine barley sources tested. With R² values exceeding 0.50, significant linear regression equations for CP and threonine were obtained. In conclusion, significant differences existed in the ileal digestibility of CP and AAs among barley varieties. It is difficult to predict the SID of most of the amino acids in barely based upon chemical characteristics.     

Additivity of standardized ileal digestibility of amino acids in mixed diets containing multiple protein sources for growing pigs fed three crude protein levels

This study was conducted to investigate the effect of dietary crude protein (CP) levels of semi‐purified diets on the additivity of values for standardized ileal digestibility (SID) of amino acids (AA) in mixed diets from multiple protein sources for growing pigs. A total of 28 barrows (initial BW, 66.4 ± 1.3 kg) were surgically fitted with simple T‐cannulas at the distal ileum and assigned to a replicated 14 × 4 incomplete Latin square design with 14 diets and 4 periods. The 14 experimental diets consisted of a nitrogen‐free diet; a corn‐based diet (80 g CP/kg); nine semi‐purified diets containing soya bean meal (SBM), canola meal (CM) or corn distillers dried grains with solubles (cDDGS), each type (protein source) of semi‐purified diets supplied 80, 120 or 160 g CP/kg, respectively; three mixed diets based on corn, SBM, CM and cDDGS formulated to contain 120, 160 and 200 g CP/kg respectively. Pigs were fed each of the 14 diets during a seven‐day period, and ileal digesta were collected from 08:00 a.m to 6:00 p.m on day 6 and 7. Chromic oxide was added as an indigestible marker. Results indicated that the SID of CP and AA were not affected by CP levels (p > .05). Values for SID of AA were additive (p > .05) with the exception of His and Lys; Arg and Lys; Arg, Lys, Thr, Asp, Cys and Gly in the mixed diets containing 120, 160 and 200 g CP/kg respectively (p < .05). In conclusion, additivity of SID values of AA in the mixed diets at different CP levels was not affected by the CP levels of semi‐purified diets for growing pigs. Therefore, it is recommended that SID values of AA should be used to formulate practical diets containing multiple ingredients for pigs.     

Partial dehulling of barley effect the concentrations of both gross and ileal digestible amino acids in pigs

Five barrows (58 kg initial BW, 80 kg final BW) fitted with an ileo-rectal anastomosis were used to determine the effect of partial dehulling of two- and six-row barley varieties on the concentrations of ileal digestible amino acids (AA). The following diets were provided according to a standardized diet formulation and tested in five consecutive periods (repeated group-period design): two-row barley (TRB) + casein (C), dehulled TRB (TRB-H) + C, six-row barley (SRB) + C, dehulled SRB (SRB-H) + C, and wheat starch + C. Daily rates of approximately 80 g DM × kg BW^− 0.75 in barley diets and 49 g DM × kg BW^− 0.75 in the casein diet were supplied. The digestibility of AA in barley was determined by the difference method (casein as basal diet) using quantitative ileal effluent collection.

In TRB and SRB the ID of CP and AA did not differ. As demonstrated on selected key AA there were increases of both concentrations of gross AA and of ileal AA digestibility duo to dehulling. Consequently, the contents of ileal digestible AA were raised by up to 39% for lysine and 38% for methionine in TRB-H and SRB-H, respectively.