Endogenous Amino Acid Losses Research Articles

Oligosaccharides are a key factor in prediction of amino acid digestibility in soybean meal of different origins when fed to growing pigs.

ObjectiveThe objective of this experiment was to determine apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of crude protein (CP) and amino acid (AA) in 15 sources of soybean meal (SBM) produced from soybeans from different countries and subsequently to establish equations for predicting the AID and SID in SBM based on their chemical composition.MethodsEighteen barrows (57.9±6.1 kg) fitted with a simple T-cannula were allotted into three 6×6 Latin square designs. Each period comprised a 6-d adaption period followed by a 2-d collection of ileal digesta. The 15 test diets included SBM as a sole source of AA in the diet. Another nitrogen-free diet was used to measure basal endogenous losses of CP and AA. Chromic oxide (0.3%) was used as an inert marker in each diet.ResultsThe AID of lysine in SBM from China and USA tended to be greater than in SBM from Brazil (p<0.10). The SID of valine and proline in SBM from China was greater than in SBM from Brazil (p<0.05). The SID of lysine, threonine, cysteine and glycine in SBM from China tended to be greater than in SBM from Brazil (p<0.10). From a stepwise regression analysis, a series of AID and SID prediction equations were generated. The best fit equations for lysine in SBM were: AID lysine = 1.16 sucrose−1.81 raffinose+82.10 (R2 = 0.69, p<0.01) and SID lysine = 1.14 sucrose−1.93 raffinose−0.99 ether extract (EE)+85.26 (R2 = 0.77, p<0.01).ConclusionIt was concluded that under the conditions of this experiment, the oligosaccharides (such as sucrose and raffinose) can be used to predict the AID and SID of AA in SBM with reasonable accuracy.

Ileal endogenous losses in pigs feeding a protein-free diet or diets with different contents of casein or crystalline amino acids

ABSTRACTThe common usage of protein-free diets to estimate unspecific AA losses has been criticised as unphysiological and incorrect. Therefore, in this study different diets were tested for the determination of endogenous losses (EL) of amino acids (AA) and nitrogen (N) assuming a complete absorption in the small intestine. Seven cannulated gilts received a protein-free diet (Diet PF) or diets with 3%, 6% or 10% crude protein (CP) from crystalline AA (Diets CA) or casein (Diets CAS) according to a 7 × 7 Latin square design. After 6 d adaptation to the diet, ileal digesta was collected for 24 h and thereafter analysed for AA, N and the digestibility markers Cr2O3 and acid insoluble ash (AIA). Generally, among all AA, the highest amounts of EL were found for Pro, Glu and Gly, and the smallest for Met. Different levels of CP in Diets CA and CAS had no effect on EL. Significant differences between treatments were observed only for the EL of Glu, Ile, Ser (higher in Diets CA and PF), Pro and Tyr (higher in Diet PF) (p < 0.05). There were no differences in determined EL using Cr2O3 or AIA as digestibility markers.

Effects of collection time on flow of chromium and dry matter and on basal ileal endogenous losses of amino acids in growing pigs.

The objectives of this experiment were to examine the diurnal patterns of chromium and DM flow at the distal ileum of pigs and to determine the effect of collection time on basal ileal endogenous losses (BEL) of CP and AA. Eight barrows with an initial BW of 34.6kg (SD = 2.1) were individually fitted with a T-cannula in the distal ileum and randomly allotted to a replicated 4× 4 Latin square design with 4 diets and 4 periods in each square. Three diets contained either corn, soybean meal, or distillers dried grains with solubles as the sole source of CP and AA. An N-free diet was also prepared. All diets contained 0.5% chromic oxide as an indigestible marker. Equal meals were provided at 0800 and 2000 h. Ileal digesta samples were collected in 2-h intervals from 0800 to 2000 h during the last 3 d of each 7-d period. The concentration of Cr in ileal digesta samples collected in each of the six 2-h periods exhibited a quadratic effect ( < 0.01) that increased and then decreased in pigs fed the CP containing diets. However, the concentration of Cr in ileal digesta collected in each of the six 2-h periods from pigs fed the N-free diet increased (linear, < 0.01). These differences were possibly related to differences in DM flow, because DM flow to the distal ileum had a pattern that was opposite of that observed for the concentration of Cr in the ileal digesta samples. The BEL of all indispensable AA and the sum of indispensable AA from pigs fed the N-free diet decreased (linear, < 0.05) in each of the six 2-h periods, with the exception that the BEL of Arg increased and then decreased (quadratic, < 0.05). The BEL of Asp, Cys, Glu, Ser, and Tyr also decreased (linear, < 0.05) during each of the six 2-h periods, whereas the BEL of Pro and the sum of dispensable AA increased and then decreased (quadratic, < 0.05) over the 12 h. Collection time did not affect BEL of CP. No differences were observed in the concentration of Cr, flow of DM, or basal endogenous loss of all AA if ileal digesta samples were collected over 6-, 8-, or 10-h periods, compared with collection over a 12-h period. In conclusion, diurnal variation of Cr concentration, DM flow, and the BEL of all AA were observed, but 4 to 6 h of ileal sample collection starting 4 or 6 h after feeding may provide representative samples that allow for calculation of accurate values for CP and AA digestibility.

Nutritive value of cold-pressed camelina cake with or without supplementation of multi-enzyme in broiler chickens

The objectives were to determine the standardized ileal digestibility (SID) of amino acids (AA) and AMEn value of cold-pressed camelina cake (CPCC) and the effect of adding multi-enzyme to a corn-CPCC diet for broilers. The 600 male broiler chicks were divided into 40 groups and fed 5 diets in a completely randomized design (8 groups per diet) from d 15 to d 21 of age. A corn basal diet and the basal diet with 30% of it replaced by CPCC were used in a 2 × 2 factorial arrangement with or without multi-enzyme (2,800 U of cellulase, 1,800 U of pectinase, 400 U of mannanase, 50 U of galactanase, 1,000 U of xylanase, 600 U of glucanase, 2,500 U of amylase, and 200 U of protease/kilogram of diet; Superzyme OM, 1 g/kg). The fifth diet was N-free. The corn basal diet was fed to determine nutrient digestibility and retention for CPCC by substitution. The N-free diet was fed to estimate basal endogenous AA losses for determining SID of AA. Diets contained TiO2 as indigestible marker. On a DM basis, CPCC contained 39.8% CP, 38.3% neutral detergent fiber, 12.7% ether extract, 1.89% Lys, 0.70% Met, 1.56% Thr, and 0.45% Trp. The SID of Lys, Met, Thr, and Trp for CPCC were 76.5, 85.5, 72.8, and 84.1%, respectively. The AMEn value for CPCC was 1,671 kcal/kg of DM. Multi-enzyme supplementation increased (P < 0.05) the SID of Met and Thr and the AMEn value of the corn-CPCC-based diet by 1.4, 1.3, and 3.0%, respectively. The multi-enzyme increased (P = 0.026) the AMEn value of CPCC from 1,671 to 1,941 kcal/kg of DM. In conclusion, the CPCC evaluated in the present study can be included in poultry diets as a source of energy and AA. Multi-enzyme supplementation increased the AMEn value of CPCC for broilers.

Determination of basal ileal endogenous losses and standardized ileal digestibility of amino acids in barley fed to growing pigs.

BackgroundBasal ileal endogenous amino acid (AA) losses (IAAend) and standardized ileal digestibility (SID) values of cereal grains, such as barley, are apparently underestimated when determined according to the nitrogen (N)-free method. Regression analysis between the dietary apparent ileal digestible content (cAID) and total crude protein (CP) and AA can be considered as alternative approach to obtain more accurate values for IAAend and SID of AA in cereal grains.MethodsEight hulled barley genotypes were used, with barley being the only source of CP and AA in the assay diets. The diets contained 95 % as-fed of these eight barley genotypes each, ranging in CP content between 109.1 and 123.8 g/kg dry matter (DM). Nine ileally T-cannulated barrows, average body weight (BW) 30 ± 2 kg, were allotted to a row-column design comprising eight periods with 6 d each and nine pigs. On d 5 and the night of d 6 of every period, ileal digesta were collected for a total of 12 h. The IAAend and the SID were determined by linear regression analysis between cAID and total dietary CP and AA.ResultsThere exist linear relationships between cAID and total CP and AA (P < 0.001). The IAAend of CP, Lys, Met, Thr and Trp amounted to 35.34, 1.08, 0.25, 1.02 and 0.38 g/kg DM intake (DMI), respectively, which are greater compared to average IAAend determined previously under N-free feeding conditions. The SID of CP, Lys, Met, Thr and Trp was 90, 79, 85, 79 and 86 %, respectively, and was greater when compared to tabulated values. Moreover, these SID values were greater than those reported in literature, based on correction of apparent ileal digestibility (AID) of CP and AA for their IAAend values. Summarized, the results of the present regression analysis indicate greater IAAend in barley-based diets compared to those obtained by N-free feeding.ConclusionsFor low-protein feed ingredients like barley the regression method may be preferred over correction of AID values for their IAAend determined under N-free feeding conditions, as intercepts and slopes of the linear regression equations between cAID and total dietary CP and AA provide direct estimates of IAAend and SID of CP and AA in the presence of the assay feed ingredient.

Standardized ileal digestibility and basal ileal endogenous loss of amino acids associated with triticale genotypes in growing pigs1

Standardized ileal digestibility and basal ileal endogenous loss of amino acids associated with triticale genotypes in growing pigs1

Ileal endogenous loss and standardized ileal digestibility of amino acids in rye genotypes for pigs1

Ileal endogenous loss and standardized ileal digestibility of amino acids in rye genotypes for pigs1

Determination of basal ileal endogenous loss and standardized ileal digestibility of amino acids in wheat genotypes by regression analysis for grower pigs1

Determination of basal ileal endogenous loss and standardized ileal digestibility of amino acids in wheat genotypes by regression analysis for grower pigs1

An overview of energy and protein utilisation during growth in simple-stomached animals

The biological processes underlying the partitioning of amino acids and energy during animal growth are well understood qualitatively. However, if a deeper mechanistic understanding is to be achieved, such as to allow generalised predictions of growth outcomes, these biological processes need to be described quantitatively, along with critical control points. Concepts and rules can be formulated at mechanistic and semi-mechanistic levels, and often reflecting causation, to allow nutrient intake and partitioning to be described in a quantitative manner for different animal and environmental conditions. An overview is given of amino acid and energy partitioning during growth in monogastric animals, in terms of causation and quantitatively based descriptors. Current knowledge is far from complete, and areas requiring new insights and a more in-depth understanding of causative mechanisms include voluntary food-intake control, dynamics of nutrient uptake, temporary post-prandial nutrient storage, relationships among nutrient intakes, protein turnover and maintenance-energy requirement, colonic amino acid uptake in poultry, bioavailability of amino acids other than lysine, diet effects on gut endogenous amino acid loss, inevitable amino acid catabolism, preferential amino acid catabolism, and diet, age and genotype effects on body protein synthesis and degradation.

Ileal amino acid digestibility in high protein sunflower meal and pea protein isolate fed to growing pigs with or without multi-carbohydrase supplementation

Amino acids are the second most expensive nutrients in practical pig and poultry diets after energy. High protein sunflower meal (HiPSF) and pea protein isolate (PPI) are potential alternative protein sources for soybean meal and there is a great interest to explore their utilization as dietary ingredients for swine. Thus, eight ileal-cannulated barrows (initial BW=23.5±0.9kg) were used to determine the apparent (AID) and standardized (SID) ileal amino acid (AA) digestibilities in HiPSF and PPI with or without multi-carbohydrase enzyme (MC) supplementation. Pigs were randomly assigned to 1 of 5 treatments in a replicated 4×5 incomplete Latin square design to give 8 observations per treatment. The experimental diets consisted of HiPSF or PPI as the sole source of protein with or without MC and a low-protein diet (5% casein) used to quantify endogenous AA losses. All diets contained titanium dioxide (0.3%) as an indigestible marker. Pigs were given their daily feed allowance at a rate of 4.5% of BW determined at the beginning of each experimental period. Each experimental period lasted for 7 d and the ileal digesta were collected on d 6 and 7. In general, AA digestibilities were higher in PPI than in HiPSF, with the exception of Met and Cys. There was no effect of MC on AA digestibility except for Lys, Ala, Cys and Pro in PPI. The AID and SID of essential AA in HiPSF and PPI (without MC) were, respectively: Arg, 0.86, 0.90 and 0.92, 0.95; His, 0.45, 0.54 and 0.58, 0.67; Ile, 0.78, 0.83 and 0.86, 0.90; Leu, 0.77, 0.81 and 0.86, 0.90; Lys, 0.71, 0.77 and 0.89, 0.92; Met, 0.85, 0.88 and 0.84, 0.87; Phe, 0.79, 0.82 and 0.86, 0.88; Thr, 0.68, 0.77 and 0.77, 0.85; Val, 0.75, 0.80 and 0.82, 0.87. The MC increased (P<0.05) the AID of Lys (0.89 vs 0.91), Cys (0.59 vs 0.62) and Pro (0.79 vs 0.85) and SID of Lys (0.92 vs 0.94), Ala (0.88 vs 0.91) and Pro (0.89 vs 0.95) in PPI. Compared to HiPSF, PPI had better digestible AA profile for growing pigs. However, no differences were detected for the digestibility of most AA when diets were supplemented with MC.

Comparative ileal amino acid digestibility of distillers' grains for growing pigs.

The objective of the experiment reported here was to investigate and compare the amino acid (AA) digestibility of distillers' dried grains (DDG), distillers' dried grains with solubles (DDGS), high protein distillers' dried grains (HP-DDG), and high protein distillers' dried grains with solubles (HP-DDGS) in growing pigs. Five semi-purified diets consisting of DDG, DDGS, HP-DDG, HP-DDGS, and nitrogen-free diet (NFD) were fed to pigs fitted with simple T-cannula for 5 observations per diet. Endogenous losses of AA at the terminal ileum of pigs that received the NFD were used to calculate standardized ileal digestibility (SID) of AA from apparent ileal digestibility (AID) of AA. The AID of Lys in DDGS was lower (P < 0.05) than that in DDG, which was also lower (P < 0.05) than that in HP-DDG. There were no differences in AID of Met among DDG, DDGS and HP-DDGS, but was greater (P < 0.05) in HP-DDG than in DDG or DDGS. The AID of Thr in HP-DDG was greater (P < 0.05) than that in DDGS but not different from that in DDG or HP-DDGS. The branched-chain AA Ile and Leu had greater (P < 0.05) AID in HP-DDG than in DDG, DDGS or HP-DDGS, and there was no difference among DDG, DDGS, and HP-DDGS. The AID of Trp in DDG and DDGS or HP-DDG and HP-DDGS were not different, but the AID of Trp in HP-DDGS was greater (P < 0.05) than that of DDGS. The greatest SID of the indispensable AA was in HP-DDG. Except for Arg and Lys in which DDG had greater (P < 0.05) digestibility, there was no difference between DDG and DDGS in the SID of the indispensable AA. The SID of Lys in DDG was greater (P < 0.05) than that of DDGS but there was no difference between that of DDG and HP-DDGS. Only His, Ile, and Met had lower (P < 0.05) SID in HP-DDGS than HP-DDG within the indispensable AA. The SID of Ala, Asp, Cys, Glu, Gly, Ser and Tyr were lower (P < 0.05) in DDGS than in HP-DDG. There SID of dispensable AA in DDG was not different from that of HP-DDGS. The current study provided apparent and standardized ileal amino acids digestibility values for traditional and high-protein corn distillers' dried grains coproducts for use in formulating swine diets. Amino acid digestibility was generally higher in HP-DDG than in other tested co-products of the dry grind processing of corn for ethanol.

Investigation of the effect of coccidial vaccine challenge on apparent and standardized ileal amino acid digestibility in grower and finisher broilers and its evaluation in 21-day-old broilers

The effect of coccidial vaccine challenge (CVC, Coccivac(®)B; challenged, CHA; or unchallenged, NCH) on ileal endogenous amino acid (IEAA) losses and standardized ileal AA digestibility (SIAAD) in 21- and 42-day-old broilers fed a corn-soybean meal-dried distillers' grains with solubles-poultry by-product meal-based diet (Expt.1) and the effect of supplemental AA in ameliorating the effect of CVC (Expt.2) were evaluated. Expt.1 was designed as a 2 (d 21 or 42) x 2 (NCH or CHA) factorial arrangement of treatments with 8 replicates in a complete randomized design. The CVC birds were gavaged with 12 x coccidial vaccine on d 15 and 36 and were sampled on 6 d post challenge. SIAAD was determined by correcting apparent ileal AA digestibility for IEAA losses. Feed intake (FI) and BW gain were higher (P ≤ 0.05) in 21-day-old NCH birds compared to the 21-day-old CHA birds while 42-day-old birds had higher FI and BW gain than 21-day-old NCH and CHA birds. Ileal endogenous nitrogen loss was higher (P ≤ 0.05) in 42-day-old CHA birds compared to 42-day-old NCH birds. Apparent ileal AA digestibility in 21-day-old CHA birds was lower (P ≤ 0.05) than for 21-day-old NCH and 42-day-old NCH and CHA birds. SIAAD in 21-day-old CHA birds was lower (indispensable AA = 15.2 and dispensable AA = 17.8%-unit; P ≤ 0.05) than for 21-day-old NCH and 42-day-old NCH and CHA birds. Apparent ileal digestibility and total tract utilization of DM, N, and energy were not different between d 21 NCH and d 42 NCH and CHA birds but higher (P ≤ 0.05) than for d 21 CHA birds. Supplemental AA restored feed efficiency, but not BW gain, to that of the positive control (0.715vs. 0.737). Results from Expt.1 showed that CVC significantly influenced ileal AA digestibility in 21- but not in 42-day-old birds. Expt.2 showed that consideration of SIAAD in feed formulation may benefit feed efficiency.

Neutral detergent fiber increases endogenous ileal losses but has no effect on ileal digestibility of amino acids in growing pigs

Two experiments were conducted to determine the effect of neutral detergent fiber (NDF) on endogenous amino acids and protein ileal losses; and also apparent ileal digestibility (AID), and standardized ileal digestibility (SID) of amino acids and crude protein. Sixteen barrows were fed four protein-free diets containing graded NDF levels in Experiment 1. NDF was a mixture of sugarcane bagasse and corn leaves (SBCL). Twenty-four barrows were fed diets with soybean protein concentrate (SPC) or casein as protein sources and SBCL or corncobs (CC) as NDF sources in Experiment 2. In Experiment 1, a linear increase (P < 0.05) in endogenous amino acid and protein ileal losses was observed with increased NDF levels, except for arginine, histidine, methionine and proline. In Experiment 2, protein (P < 0.001) and NDF (P < 0.01) sources significantly affected AID of dry matter, which was higher in casein diets (71.7%) and CC diets (70.7%). Protein and NDF sources significantly affected (P < 0.05) SID of crude protein, which was higher in casein diets (92.8%) and CC diets (92.7%). NDF source had no effect (P > 0.05) on SID of amino acids. Overall, this study showed that NDF increased endogenous amino acid and protein ileal losses, but did not affect ileal digestibility of amino acids.

Basal endogenous losses of amino acids in protein nutrition research for swine and poultry

In this review, the definition and terminology of amino acid (AA) digestibility and ileal endogenous losses of AA (IAAend) in poultry and swine nutrition are discussed. Compared with apparent (AID) and true (TID) ileal digestibility, standardised ileal digestibility (SID) of AA is recommended for the expression of digestible AA contents of feed ingredients and for describing nutritional requirements of poultry and swine. To determine the SID of AA, total ileal flow of AA should be corrected for basal IAAend. Therefore, the measurement of basal IAAend is of great importance for the accuracy of the SID estimation in feed ingredients. The techniques for measuring basal IAAend in poultry and swine include the use of a nitrogen-free diet (NFD), a highly digestible or enzyme hydrolyzed protein diet, and the regression method. The classic method for basal IAAend determination involves the feeding of a NFD to experimental animals and measuring the ileal AA flow. This IAAend output is considered as basal IAAend, and it is assumed that the excretion of basal IAAend depends only on DM intake, regardless of dietary composition. There are criticisms with the NFD method about the abnormal physiological state induced by severe AA deficiency. Although this AA deficiency may affect the estimate of basal IAAend for dispensable AA, especially proline and glycine because of the degradation of body protein, the NFD method is still the most widely used method for basal IAAend measurements. According to the definition of basal IAAend, the NFD should be the preferred methodology in SID determination, because the basal IAAend should be only related to dry matter intake. Additionally, the SID coefficients in feed ingredients generated by NFD method are considered to be additive in a complete diet. However, the results generated from NFD method can vary among studies due to the variance in the experimental animals and diet composition. To improve the accuracy of estimating the SID of AA in feed ingredients, it is suggested that a mandatory NFD be included in individual studies to generate basal IAAend for correcting total ileal amino acid flow in determining SID of AA. In addition, research is needed to investigate the standard diet formulation of NFD.

Feed-induced specific ileal endogenous amino acid losses: Measurement and significance in the protein nutrition of monogastric animals

The endogenous ileal amino acids recovered at the terminal ileum of monogastric animals comprises of two components, namely basal and specific losses. The basal losses are fixed and associated with feed dry matter intake, whereas the specific losses are variable and induced by the presence of dietary components, such as fibre and anti-nutrients. Currently there is no methodology available to directly measure the specific endogenous losses. These losses are calculated by determining the basal and total (basal plus specific) losses and then subtracting the basal losses from total losses. Two techniques, namely the guanidination and isotope markers, can be used for the determination of total endogenous amino acid losses. The fundamental features, specific applications and shortcomings of these two methodologies are discussed. Although the specific endogenous protein losses are significant metabolic costs to the animal, published data quantifying these losses are limited owing to the complexity of available methodologies.

Effects of dietary cellulose levels on the estimation of endogenous amino acid losses and amino acid digestibility for growing pigs.

Two experiments were conducted to investigate the effects of dietary cellulose levels on the determination of the ileal endogenous losses (IEL) of amino acids (AA), apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of AA in corn-soybean meal diets for growing pigs. In the first experiment, 28 pigs (BW, 45.1 ± 2.0 kg) that were fitted with simple T-cannulas at the distal ileum were fed 4 nitrogen-free diets consisting of 4 dietary cellulose levels (0, 3%, 6% and 9%) in a randomized complete block design. In the second experiment, 28 pigs (BW, 45.6 ± 2.0 kg) fitted with simple T-cannulas at the distal ileum were fed 4 corn-soybean meal diets consisting of 4 dietary cellulose levels (0, 3%, 6% and 9%) in a randomized complete block design. There were 7 replicates per diet with 1 pig as a replicate in each treatment. Both experiments consisted of a 7-d adjustment period and a 2-d ileal digesta collection period on d 8 and 9. Chromic oxide was used as an indigestible marker to calculate IEL and digestibility of AA. The results showed that the IEL of AA for growing pigs was not influenced by dietary cellulose supplementation (P > 0.05). The AID of Thr, Ser, Glu, Cys, Ile, Tyr, Phe, Lys and His decreased with increasing cellulose supplementation levels for pigs fed corn-soybean meal diets (P < 0.05). The SID of Thr, Ser, Cys, Val, Ile, Tyr, Phe, Lys and His decreased with increasing cellulose supplementation levels in corn-soybean meal diets (P < 0.05). In summary, dietary cellulose levels had no effect on the estimation of IEL of AA for growing pigs. The AID and SID of most AA in corn-soybean meal diets decreased with increasing levels of dietary cellulose supplementation.

Ileal Amino Acid Digestibility of Broken Rice Fed to Postweaned Piglets with or without Multicarbohydrase and Phytase Supplementation.

Most of amino acid (AA) digestibility values for feed ingredients are obtained using pigs cannulated in the distal ileum. The ileal-cannulated pig model uses pigs older than six weeks due to difficulties related to implanting the T-cannula in distal ileum of younger pigs and complications during the post-surgical recovery. However, to properly formulate the diet of weaned pigs, the nutritive value of feed ingredients should be determined with younger pigs. Thus, 25 weaned pigs were used to determine the apparent total tract digestibility (ATTD) of nutrients, energy, and apparent ileal digestibility (AID) and standardized ileal digestibility (SID) ileal AA digestibility of broken rice (BR), with or without multicarbohydrase (MC) and phytase (Phy) supplementation. Piglets were weaned at 23 d of age and individually housed in digestibility cages until 45 d of age. The trial consisted of 7 d of adaptation to the experimental diets and 3 d of excreta (feces and urine) collection. Ileal digesta was collected at slaughter (about 6 weeks of age). A completely randomized experimental design was used to determine the effects of MC and Phy. Reference diets (RD, 5% casein) was replaced by 30% of BR with or without MC, Phy, or MC+Phy. The RD was used to quantify endogenous AA losses. BR with Phy supplied had increased the ATTD of dry matter (p<0.05) and SID of histidine (p = 0.05), arginine, leucine, lysine, valine, alanine, and proline (p<0.05). BR with MC had been increased digestible energy and protein and SID for histidine (p<0.05). There was no interaction between Phy and MC on the BR nutrient digestibilities. Standardized amino acid digestibilities of BR, without enzymes, were lower than those values reported in the literature. The MC and Phy improved the digestibility of some nutrients and energy of BR in post-weaned piglet diets.

Effects of graded fiber level and caecectomy on metabolizable energy value and amino acid digestibility in geese

This study was carried out to evaluate the effects of graded levels of fiber from rice hull and the caecectomy on metabolizable energy (ME) and amino acid digestibility (AAD) in 42 Wuzong geese (21 intact and 21 caecectomized). The experiment was a 3×2 factorial randomized design with 3 fiber levels and 2 treatments of geese (caecectomized and intact). Each of the 3 diets was tube-fed (60 g) to 7 caecectomized and 7 intact adult Wuzong geese that had been fasted for 24 h. Excreta were collected for the next 48 h. The same geese were also fasted for estimation of endogenous losses of amino acids (AA) and energy after short period recovery. AA content and metabolizable energy value were determined in the excreta. In general, significant effects were found for fiber levels on apparent digestibility of Thr, Leu, Pro, Glu, Val, Ala and total AA (P<0.05). Apparent metabolizable energy (AME) and true metabolizable energy (TME) were both significantly influenced by increased fiber levels (P<0.01). Compared with caecectomized geese, markedly increases of AME and TME were found in intact geese (P<0.01 for AME and P<0.05 for TME), but no difference in the AAD were found between intact and caecectomized geese (P>0.05), except for Lys and Try (P<0.05). These observations suggested that dietary fiber level played an important role in digestibility of AAD and ME. Intact geese should be chosen for the nutrient evaluation of feedstuffs in practice, resulting from the significant difference between caecectomized and intact geese.

A comparison of the nutritional value of organic-acid preserved corn and heat-dried corn for pigs

Three experiments were conducted to compare the digestible (DE) and metabolizable energy (ME) content (Exp. 1), as well as the apparent (AID) and standardized (SID) ileal digestibility of amino acids (AA) (Exp. 2) in organic-acid preserved and heat-dried corn. In addition, the performance of weanling pigs fed diets containing the two corns was compared (Exp. 3). In Exp. 1, 12 growing barrows (28.5±1.50kg) were randomly allotted to 1 of 2 groups and fed diets containing 970g/kg organic-acid treated or heat-dried corn to determine the DE and ME content of the two differently processed corns. The results indicated that the DE and ME of organic-acid treated corn were 16.6 and 16.3MJ/kg, which was greater than the 16.4 and 15.9MJ/kg, for the DE and ME of heat-dried corn (P<0.05 and P<0.01). In Exp. 2, 18 growing barrows (27.6±4.38kg), fitted with a T-cannula in the distal ileum, were allotted to be fed 1 of 3 semi-synthetic diets with 6 pigs per treatment. Two of the 3 diets were of similar composition to those used in Exp. 1 while the 3rd was a nitrogen-free diet that was used to measure basal endogenous losses of CP and AA. The results from Exp. 2 showed no significant difference in the AID or SID of CP and AA between the 2 corns. In Exp. 3, 60 piglets, weaned at 28day (7.34±1.243kg), were randomly allotted to 1 of 2 complete diets with 5 pigs per pen and 6 pens per dietary treatment for 4 weeks. Piglets fed organic-acid treated corn had 10.5% greater average daily gain (389g/day) than pigs fed heat-dried corn (352g/day; P<0.05). Feeding organic-acid treated corn significantly increased average daily feed intake by 12.5% (604 vs. 539g/day) compared with heat-dried corn (P<0.05). In conclusion, the available energy content of organic-acid treated corn was greater than heat-dried corn, and organic-acid treated corn improved weanling pig performance.

Coated protease increases ileal digestibility of protein and amino acids in weaned piglets

The objective of this study was to determine the effect of a coated protease on apparent (AID) and standardized (SID) ileal digestibility of crude protein (CP) and amino acids (AA) in weaned piglets. Eighteen barrows with initial body weight (BW) of 13.5±0.2kg were randomly allotted to 3 diets (control, protease diet, and nitrogen-free diet) with 6 piglets per diet after fitting with a T-cannula in the distal ileum. Control and protease diets were corn–soybean meal based diet supplemented with or without 200mg/kg of coated protease. The nitrogen-free diet was used to measure basal endogenous losses of AA. The experiment lasted for 7 days, and ileal digesta were collected on days 6 and 7. Results showed that the coefficients of AID and SID of CP and total AA were increased by protease supplementation (P<0.05). For indispensable AA, the coefficients of AID of Ile, Lys, Met and Thr, and the coefficients of SID of Ile, Lys, Met, Thr and Trp were increased by protease (P<0.05). For dispensable AA, both the coefficients of AID and SID of Ala, Asp, Cys, Gly and Ser were increased by protease (P<0.05). In conclusion, dietary supplementation with coated protease increases coefficients of AID and SID of CP and most AAs in weaned piglets.