Endogenous Nitrogen Losses Research Articles

Dietary fat lowers ileal endogenous amino acid losses in broiler chickens

ABSTRACT 1. An experiment was conducted to determine the effect of the source of fat (soybean oil or tallow) on the ileal endogenous amino acid (EAA) losses in broilers. 2. Three nitrogen (N)-free diets; a control diet with no added fat and test diets with 60 g/kg of either soybean oil or tallow were formulated. Titanium dioxide (5 g/kg) was added to all diets as an indigestible marker. Each diet was assigned to six replicate cages (eight birds per cage) from d 18 to 21 post-hatch. On d 21, the digesta were collected from the lower half of the ileum. 3. The endogenous losses of nitrogen and amino acids (AA) were lower (p = 0.08; p = 0.001) in broilers fed diets with soybean oil or tallow, respectively, compared to those fed the diet with no fat. Source of fat had no influence (p > 0.05) on EAA losses. 4. The most abundant AA in the ileal endogenous protein was glutamic acid, followed by aspartic acid, threonine, leucine, serine, valine and proline. In general, the concentrations of AA in the endogenous protein were lower (p < 0.05) with added fat. The exceptions were methionine, cysteine, proline and serine, which were unaffected. The effect of fat source on the AA contents of endogenous protein were inconsistent and differed depending on the AA. 5. The inclusion of fats decreased EAA losses which implied they have beneficial effects beyond direct energy contribution. It can be proposed that the reduction of EAA flow may be an additional mechanism contributing to the extra-caloric effect of dietary fats.

A method to estimate endogenous losses of nitrogen and amino acids at the ileal level in growing rabbits

Apparent ileal digestibility can be corrected to give the true ileal digestibility of the nitrogen and amino acids provided by the diet, by determining the flow of endogenous nitrogen and amino acids (from desquamated epithelial cells of gastrointestinal mucosa, mucins and digestive enzymes). This flow of nitrogen and amino acids has been studied in adult rabbits fitted with a T-cannula, but remains unknown for growing rabbits. The aim of this work was to propose a method to estimate endogenous nitrogen and amino acid losses in the ileum of growing rabbits slaughtered at 64 d of age from 20:00 h. For this purpose, two experiments were carried out. The first was performed with 10 weaned rabbits fed with a diet with casein as the only source of protein (whose ileal digestibility is 100%) and labelled with ytterbium. This experiment allowed us to identify the relationship between the ileal flow of endogenous nitrogen (IFEN) and the dry matter intake in the last 24 h before slaughter (DMI), which fits the equation: IFEN (mg/d)=5.99 DMI (g/d) +133; (R2=0.778, residual standard deviation=138, P&lt;0.001, n=10). The second experiment was carried out with 36 rabbits fed the same diet but without ytterbium, with whose ileal content 9 pools were constituted to determine the amino acid profile of endogenous nitrogen, which was found to be rich in glutamic acid, serine, aspartic acid, glycine, valine and threonine (15.97±1.33; 8.00±0.80; 7.06±0.72; 6.24±0.77; 5.48±0.51 and 4.97±0.47 g/16 g of N, respectively) and poor in methionine and histidine (1.05±0.06 and 1.34±0.16 g/16 g of N, respectively). Knowing the DMI of a certain growing rabbit in the 24 h prior to slaughter, the combined use of the equation and the amino acid profile obtained makes it possible to estimate the ileal endogenous losses of each amino acid.

Determination of ileal endogenous nitrogen losses and true ileal nitrogen digestibility during non-steady-state conditions of the 15N-isotope dilution technique

ABSTRACT The aim was to determine ileal endogenous nitrogen losses (ENL) and true ileal N-digestibility (TD-N) under non-steady-state conditions of the 15N-isotope dilution technique (15N-IDT), using diets generating low and high ENL and compare results to those obtained under steady-state conditions. Twelve growing pigs (mean LW 22.4 kg) fitted with a post-valve T-caecum cannula were fed an enzyme-hydrolysed casein (EHC)-based diet or an EHC diet + 4% quebracho tannins (QT) and were labelled via continuous 15N-leucine i.v. infusion or twice daily oral 15N-leucine administration. Digesta were collected daily over three consecutive hours with blood plasma sampled on the four consecutive days after cessation of 15N-labelling. There was a significant effect of sampling day on the dilution factor. Endogenous N losses were significantly lower for the EHC than the EHC+QT diet (2.41 vs. 8.69 g/kg DMI), while no significant effect of sampling day was observed. The TD-N of the EHC+QT diet did not differ from the TD-N of the EHC diet (95.1 vs. 92.0%). A significant effect of sampling day was observed for TD-N with day 1 and 2, being higher than day 4. Non-steady-state conditions overestimated ENL by 25–28% as compared to 3 h collections in steady-state conditions, but the relative overestimation was similar for the EHC diet as for the EHC+QT diet. TD-N did not differ significantly compared to 12 h steady-state measurements, but comparison to 3 h steady-state measurements showed that non-steady-state conditions overestimated TD-N for the EHC+QT diet by 9%. However, on day 4 this overestimation disappeared. Using the 15N-IDT during non-steady-state conditions can provide valuable additional data on endogenous N losses and TD-N.

Characteristics of Nutrition and Metabolism in Dogs and Cats.

Domestic dogs and cats have evolved differentially in some aspects of nutrition, metabolism, chemical sensing, and feeding behavior. The dogs have adapted to omnivorous diets containing taurine-abundant meat and starch-rich plant ingredients. By contrast, domestic cats must consume animal-sourced foods for survival, growth, and development. Both dogs and cats synthesize vitamin Cand many amino acids (AAs, such as alanine, asparagine, aspartate, glutamate, glutamine, glycine, proline, and serine), but have a limited ability to form de novo arginine and vitamin D3. Compared with dogs, cats have greater endogenous nitrogen losses and higher dietary requirements for AAs (particularly arginine, taurine, and tyrosine), B-complex vitamins (niacin, thiamin, folate, and biotin), and choline; exhibit greater rates of gluconeogenesis; are less sensitive to AA imbalances and antagonism; are more capable of concentrating urine through renal reabsorption of water; and cannot tolerate high levels of dietary starch due to limited pancreatic α-amylase activity. In addition, dogs can form sufficient taurine from cysteine (formost breeds); arachidonic acid from linoleic acid; eicosapentaenoic acid and docosahexaenoic acid from α-linolenic acid; all-trans-retinol from β-carotene; and niacin from tryptophan. These synthetic pathways, however, are either absent or limited in all cats due to (a)no or low activities of key enzymes (including pyrroline-5-carboxylate synthase, cysteine dioxygenase, ∆6-desaturase, β-carotene dioxygenase, and quinolinate phosphoribosyltransferase)and (b) diversion of intermediates to other metabolic pathways. Dogs can thrive on one large meal daily, select high-fat over low-fat diets, and consume sweet substances. By contrast, cats eat more frequently during light and dark periods, select high-protein over low-protein diets, refuse dry food, enjoy a consistent diet, and cannot taste sweetness. This knowledge guides the feeding and care of dogs and cats, as well as the manufacturing of their foods. As abundant sources of essential nutrients, animal-derived foodstuffs play important roles in optimizing the growth, development, and health of the companion animals.

Research Note: Evaluation of standardized ileal amino acid digestibility in feed ingredients for Pekin ducks

The digestibility of crude protein (CP) and amino acids (AA) in feedstuffs including corn, soybean meal (SBM), and corn distillers dried grains with solubles (DDGS) was investigated in White Pekin ducks. The test ingredients were the sole source of AA and CP. A nitrogen-free diet was also formulated for determining endogenous losses of AA and nitrogen. Birds were fed a standard starter diet for the first 15 d posthatch. On d 16, 96 ducklings (860 ± 50 g BW) were selected and allocated into 1 of 4 dietary treatments containing the test ingredients with 6 replicates per treatment in a randomized complete block design. All the crumbled assay diets were offered ad-libitum for 5 d and contained chromic oxide as an indigestible marker at 0.05%. On d 21, ducks were euthanized to collect the ileal digesta for digestibility analysis. Basal endogenous losses were abundant in glutamine, aspartic acid, leucine, proline, and serine, consecutively. For apparent ileal digestibility (AID), lysine and methionine were the highest (P < 0.05) in SBM, followed by corn and DDGS. For threonine, the highest values (P < 0.05) were similarly noted for SBM, followed by DDGS and corn; the values were 80.44, 69.88, and 64.89%, consecutively. Considering standardized ileal digestibility (SID), higher values (P < 0.05) for SBM were similarly noted for all the amino acids including lysine, methionine, and threonine; the values were 89.40, 93.58, and 86.50%, respectively. Conclusively, improved AA and CP digestibility was noted with SBM. Dietary protein source affected the extent of digestibility at the distal ileum; and the utilization of digestible amino acid coefficients during ducks' feed formulation is emphasized.

Endogenous Amino Nitrogen Collected from Pigs with End-to-End Ileorectal Anastomosis is Affected by the Method of Estimation and Altered by Dietary Fiber

Endogenous protein loss at the end of the small intestine was determined in two experiments using 10 pigs surgically prepared with end-to-end ileo-rectal anastomosis to allow total collection of ileal digesta. In the first experiment pigs were fed graded protein levels of 0 (protein-free), 55, 110 or 165 g/kg diet. Optimal durations for the adaptation and collection periods were found to be 4 and 3 d, respectively (combination 4:3), as shown by the higher correlation coefficient (r2 = 0.95) between excreted and ingested nitrogen compared with the other combinations tested (5:2, 5:3, 9:3, 9:5). The estimated amounts of endogenous N and amino acids were less accurate and tended to be smaller (P < 0.20) when obtained by extrapolation to zero nitrogen intake than when measured in pigs fed the protein-free diet. The endogenous protein was rich in proline, glutamic acid, glycine, aspartic acid, serine and threonine. In comparison to other amino acid patterns, this composition suggested a low bacterial contamination of the digesta. In the second experiment three levels of dietary fiber from wheat straw, corn cobs and wood cellulose were studied in pigs fed protein-free diets. Between 17 and 34 g crude fiber/kg diet, fiber increased the endogenous losses of nitrogen and amino acids per kilogram of dry matter intake (P < 0.05), but the excretion reached a plateau at higher dietary fiber concentration (102 g/kg). In contrast, glucosamine and galactosamine excretion increased continuously and linearly (P < 0.05) with fiber intake. We conclude that endogenous amino acid loss may be considered constant at usual and high levels of the fibrous mixture under study.

Determination and prediction of digestible energy, metabolizable energy, and standardized ileal digestibility of amino acids in barley for growing pig

Two experiments were performed to determine the digestible energy (DE), metabolizable energy (ME) and standardized ileal digestibility coefficients (SIDC) of amino acids (AA) in barley for pigs, and to develop prediction equations for the DE, ME and SIDC of AA based on its chemical composition. In Exp. 1, twenty-two castrated male pigs (29.5 ± 1.3 kg) were allotted to a replicated 11 × 3 incomplete Latin square design, including 11 diets and 3 consecutive periods. A corn-soybean meal basal diet and 10 test diets containing 400 g/kg of each barley at the expense of corn and soybean meal were prepared, and all diets had a constant ratio of corn to soybean meal. Each period includes 7 d of adaption and 5 d of total feces and urine collection. The DE and ME contents were measured by the total collection method. In Exp. 2, twenty-two ileal-cannulated pigs (30.5 ± 2.1 kg) were used in a duplicated 11 × 3 incomplete Latin square design with 11 diets and three 7-day periods. Titanium dioxide (3 g/kg) was added to all diets as indicator and ieal digesta were collected on d 6 and 7 of each period. Barley was the sole nitrogen source in 10 barley diets and a nitrogen-free diet was used for the endogenous nitrogen losses. The results showed great variations in ether extract (EE), calcium (Ca), ash, acid detergent fiber (ADF) and crude fiber (CF) among samples of barley. On an air-dry basis, the DE and ME in barley for pigs were 12.26 (11.29–13.58) MJ/kg and 11.87 (10.95–13.15) MJ/kg, respectively. The optimal prediction equations for DE and ME were: DE (MJ/kg) = −23.594 + 0.358 crude protein (CP) + 0.043 EE (R2 =0.95) and ME (MJ/kg) = 0.338 + DE - 0.014 ADF (R2 =0.99), respectively. The SIDC of lysine (Lys), methionine (Met), threonine (Thr), and tryptophan (Trp) in barley were 0.767 (0.731–0.809) g/kg, 0.825 (0.803–0.872) g/kg, 0.809 (0.793–0.822) g/kg, and 0.794 (0.760–0.858) g/kg, respectively. The best-fit prediction equations for SIDC of Lys, Met, Thr and Trp in barley fed to pigs were: SIDC Lys = 0.721 + 0.002 EE (R2 =0.79), SIDC Met = 1.045–0.00041 total starch (R2 =0.69), SIDC Thr = 0.739 + 0.001 ADF (R2 =0.69) and SIDC Trp = 1.468–0.006 CP - 0.001 neutral detergent fiber (R2 =0.99), respectively. The study confirms the large variations in chemical composition of different sources of barley, which contributes to the differences of DE, ME and SIDC of AA in barley fed to pigs and the fiber fraction can be used as key predictors.

Comparative ileal digestibility of gross energy and amino acids in low and high tannin sorghum fed to growing pigs

Low tannin sorghum cultivars (LTS) have been previously proved to contain greater available energy and apparent total tract digestibility (ATTD) of gross energy (GE) and crude protein (CP) than high tannin sorghum cultivars (HTS); however, their comparative ileal digestibility of energy and nitrogen excluding microbial interference in pigs remains mostly unknown. This study was designed to compare apparent (AID) and standardized ileal digestibility (SID) of amino acids (AA) associated with the AID and hindgut disappearance (HGD) of GE and CP in 4 LTS and 4 HTS fed to growing pigs. Eighteen barrows (27.6 ± 3.5 kg) fitted with a distal ileum T-cannula were allotted to a replicated 9 × 3 Youden square design with 9 diets and 3 periods to give a total of 6 replicate pigs per diet. Each period lasted 10 days, with 5 days adaption to the diets followed by 3 days collection of faeces and then 2 days collection of ileal digesta. Eight sorghum diets contained 966 g/kg sorghum grain as the only source of dietary energy and nitrogen, and one nitrogen-free diet was used to determine basal ileal endogenous nitrogen loss. Mean AID, ATTD, and HGD of GE and CP were higher in LTS than in HTS (P < 0.05). Mean SID of 8 out of 15 AA were decreased in HTS (P < 0.05). The AID, ATTD, and HGD of GE or CP had a negative correlation with condensed tannins and total phenolics in sorghum grain (P < 0.05). The SID of essential AA, including lysine, threonine, valine, histidine, and arginine, were highly or moderately negatively correlated with condensed tannins and total phenolics content in sorghum grains (P < 0.05). Overall, HTS provided less ileal digestibility and hindgut disappearance of energy and nitrogen, implying that condensed tannins in sorghum grain may impede nutrient digestibility, not only in the foregut but also in the hindgut segements of pigs.

O188 Estimating endogenous nitrogen losses in ileal digesta of broiler chicken fed fibres differing in particle size and solubility by 15N-isotope dilution technique

O188 Estimating endogenous nitrogen losses in ileal digesta of broiler chicken fed fibres differing in particle size and solubility by 15N-isotope dilution technique

Contribution of purified soybean trypsin inhibitor and exogenous protease to endogenous amino acid losses and mineral digestibility

The primary objective of the current study was to evaluate the impact of trypsin inhibitor (TI) and exogenous protease supplementation on endogenous loss of amino acids (AA) in broiler chickens. A total of 384 Cobb-500 broiler chicks were allocated to 4 nitrogen-free diets, each with 8 replicate cages and 12 birds per replicate. The diets were arranged as a 2 × 2 factorial with factors being dietary TI (0 or 8,000 TIU/g) and exogenous protease (0 or 15,000 PROT/kg). Desired dietary TI concentration was achieved by addition of commercially available, purified soybean TI. There was no effect of TI or exogenous protease or their interaction on growth performance of birds. However, the endogenous loss of nitrogen (N) and all AA increased (P < 0.05) due to dietary TI concentration except for Cys. The increase in endogenous AA due to TI ranged from 17% for Thr to 52.2% for Trp. Exogenous protease had no effect on endogenous loss of N and all AA. There was no effect of TI or exogenous protease or their interaction on the AID of P, however AID of Ca, Fe, Mg, Mn, and Cu was reduced (P < 0.05) due to dietary TI. The AID of Cu (P < 0.01) and K (P < 0.05) improved with exogenous protease supplementation. Significant interactions (P < 0.05) between exogenous protease and TI existed for Zn, Mg, Cu, and Na. The concentration (g/kg DM intake) of crude mucin and sialic acid increased (P < 0.05) with increased dietary TI. Decreased trypsin (P < 0.001) and increased chymotrypsin (P < 0.001) activity in the pancreas were observed as a result of exogenous protease supplementation. In conclusion, the current study showed that TI increases the endogenous loss of AA and reduced the digestibility of minerals in broiler chickens. Furthermore, exogenous protease did not affect endogenous AA flow, irrespective of added purified dietary TI.

Endogenous Losses of Nitrogen and Protein Requirement for Maintenance of Sheep

FOUR fistulated and four intact West African dwarf Sheep, maintained on hay and concentrate supplements were used for a study of metabolic faecal nitrogen (MEN) endogenous urinary nitrogen (EUN). The composition of the faecal losses was examined. The values obtained enabled calculation of nitrogen requirement of the sheep for maintenance, as well as the value of the experimental rations in the nutrition of the sheep. Values of MFN obtained by two methods were 3.31 and 3.10 g/kg Dry matter (DM) intake. Endogenous urinary nitrogen value was 0.024 g/day per metabolic weight (Wkg0.75.) Analysis of the faeces of the sheep showed that 21.1% of faecal nitrogen (N) were present as microbial and endogenous nitrogen (MEN) and 17.3% was present as water-soluble nitrogen. The biological values (BV) of the rations ranged from 85.7% to 100.0% and the digestibility for maintenance, were 1.20 and 0.41 g/day/Wkg 0.75 during the feeding trials. Values obtained for endogenous N losses and N requirement for low maintenance were low compared with reported values and this may indicate adaptation of the dwarf sheep for survival under inadequate dietary protein supply.

Effect of dietary reduction and sex class on nutrient digestibility, nitrogen balance, excreted purine derivatives and infrared thermography of hair lambs

AbstractAn experiment was conducted to evaluate whether dietary reduction and sex class affect nutrient intake, digestibility, purine derivative (PD) excretion and heat tolerance coefficient in lambs. Thirty-five hair lambs (14.5 ± 0.89 kg initial body weight (BW), 2 months old) were used in a completely randomized study with a 3 × 3 factorial arrangement, three sex classes (11 intact males, 12 castrated males and 12 females) and three levels of feeding (ad libitum, 300 and 600 g/kg/dry matter (DM) feed restriction) for 120 days. Intact and castrated males showed higher intakes of DM and neutral detergent fibre corrected for ash and protein (NDFap) than females. At 300 g/kg/DM feed restriction, NDFap digestibility was lower in intact males than in other classes; however, no differences were found between classes when subjected toad libitumfeeding or 600 g/kg/DM. The basal endogenous nitrogen and endogenous urinary losses were highest in intact males. Allantoin, uric acid and PD excretion, as well as PD absorption and microbial protein production were lowest in the animals subjected to 600 g/kg/DM feed restriction. Microbial protein synthesis (MPS) was highest in animals subjected to 600 g/kg/DM feed restriction. The lowest temperatures were observed in animals subjected to 600 g/kg/DM feed restriction. The heat tolerance coefficient was highest in animals subjected to 600 g/kg/DM feed restriction. In conclusion, feed restriction reduced the time spent on feeding and rumination but increased the digestibility of DM. The restriction level of 600 g/kg/DM maximized MPS and infrared thermography indicated an elevated heat tolerance coefficient.

298 Effect of an Insoluble Fiber Source on Energy and Nitrogen Digestibility, and on Basal Intestinal Endogenous Losses of Nitrogen and Acid Hydrolyzed Ether Extract, in Growing Pigs.

298 Effect of an Insoluble Fiber Source on Energy and Nitrogen Digestibility, and on Basal Intestinal Endogenous Losses of Nitrogen and Acid Hydrolyzed Ether Extract, in Growing Pigs.

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.

Determination of standardized prececal protein digestibility of canola meal in British United Turkeys Big 6 at different ages using multiple linear regression procedure

ABSTRACT- Ninety six 2-week-old British United Turkeys (BUT) Big 6 were assigned to 2 groups (4 replicates of 12 birds each). One basal diet and another one in which 20% canola meal replaced the corn starch in the basal diet were prepared. At 9, 16 and 21 wk of age, four birds from each pen slaughtered for digesta collection. The last two-third segment of the intestine, between the Meckel’s diverticulum and about 2 cm anterior to the ileo-ceca-colonic junction, was excised. The diets and digesta were analyzed for dry matter, crude protein, and chromic oxide content. The standardized prececal protein digestibility of canola meal was calculated using multiple linear regression procedure. The standardized prececal protein digestibility of canola meal at 21 wk of age was significantly lower as compared with that of 9 wk of age; the relative weight of digestive organs also decreased significantly with increasing age (P< 0.05). By using multiple linear regression which accounted for the endogenous nitrogen losses, we showed that standardized prececal protein digestibility was also influenced by the age.

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.

Effects of total collection method and dietary enzyme supplementation on the energy utilisation and metabolisable energy values of diets fed to broiler chickens

Summary This experiment was conducted to determine the effects of dietary enzyme supplementation on the energy utilisation and metabolisable energy values of diets fed to broiler chickens using 2 different total collection methods. The experiment was performed using a completely randomised design with a 2 × 2 factorial arrangement of two total collection methods (marker to marker method or precision-fed method) and two dietary treatments (with or without 1Â g/kg dietary multi-enzyme supplementation). A total of 48 35-day-old Ross 308 broiler chickens were randomly allotted to one of two total collection methods, and within each method, birds were randomly assigned to one of two dietary treatments with 6 replicates of two birds (one male and one female) per replicate. Additional 12 birds were used to estimate endogenous losses of gross energy (GE) and nitrogen (N).

Prediction of standardized ileal digestibility and essential amino acid content of ingredients in swine: A meta-analysis

Abstract Amino acid (AA) composition and digestibility are major determinants of nutritional value. These factors vary considerably in animal feed ingredients. For pig feed ingredients, standardized ileal digestibility (SID) is commonly used as an estimate of nutritional AA value. In this study, relationships between ingredient proximate composition and AA content, AA content and essential AA apparent ileal digestibility (AID), and between SID and AID were characterized using databases compiled from published research. The effects of ingredients (cereals, cereal by-products, oilseeds, legume seeds and oilseed meals), surgical procedure (T-cannula, re-entrant cannulas, post-valve T-cannulas and ileorectal anastomy) and animal weight (≤ or >25 kg) were modelled. Relationships between independent variables were examined for each AA to avoid co-linearity. The best predictor of AA content was crude protein (significant slope, P 0.1) nor the basal endogenous nitrogen loss estimation method (P > 0.1) appeared to affect the accuracy of essential AA (EAA) AID estimation from tEAA and EAA SID estimation from AID. Apparent ileal digestibility was the best predictor of essential EAA SID (R2 = 0.911–0.987), slope near unity and a significant intercept representing basal endogenous nitrogen loss). Compared to published models, the studied models had improved R2 and offered better accuracy.

Endogenous praecaecal and total tract losses of nitrogen in pancreatic duct-ligated minipigs

The pancreatic duct-ligated minipig (PL) is an established model of pancreatic exocrine insufficiency (PEI) with a significant decrease of nutrient digestibility. This study aimed to quantify and compare endogenous losses of nitrogen (N) (ileal and faecal) in minipigs receiving an almost N-free diet. Altogether, 12 Göttingen minipigs (7 PL and 5 control animals) fitted with an re-entrant ileo-caecal fistula were used. In Study 1, ileal digesta was collected over a period of 12 h on seven consecutive days, including one 24 h collection, when animals were fed a diet containing 0.49 g N/kg dry matter (DM). In Study 2, faeces were collected for 10 consecutive days. In Group PL, the amount and DM content of ileal digesta were higher (p < 0.05), while N concentration was lower than in the Control. The ileo-caecal N flux [g/kg DM intake] was about 2.5 times higher in Group PL (5.47 ± 1.15) than in the Control (1.91 ± 0.59) (p < 0.05). The amount of faeces did not differ, but faecal N losses were higher in Group PL (p < 0.05). Endogenous faecal N losses [g N/kg DM intake] of the Control group (1.17 ± 0.72) were comparable with earlier studies, while those of Group PL were 2.6 times higher (3.09 ± 1.34). In contrast, urinary excretion of N did not differ between the Control and Group PL. In conclusion, PEI caused markedly increased endogenous N losses. Therefore, the impact of reduced digestibility of nutrients on endogenous N losses might be relevant for apparent protein digestibility rates and should be taken into account.

Effect of concentrates restriction on feed consumption, diet digestibility, and nitrogen utilization in captive Asian elephants (Elephas maximus).

In order to study the effect of concentrates restriction on feed consumption, diet digestibility, and utilization of nitrogen in captive Asian elephants (Elephas maximus), two feeding trials were conducted on three juveniles, four sub-adults, and three adults. During trial I, the conventional zoo diets of juveniles, sub-adults, and adult contained 22, 17, and 16% of concentrates on dry matter (DM) basis, respectively. During trial II, the amount of concentrate was reduced by 50%. A digestion trial of five days collection period was conducted during each period. The animals ate more roughages when concentrates were restricted. Intake of DM (g/kg BW(0.75) /day) was highest in sub-adults, followed by juveniles and adults. Apparent digestibility of crude protein (CP), neutral detergent soluble (NDS), and supply of digestible energy (DE) was highest in juveniles, followed by sub-adults and adults. Based upon the estimated metabolic fecal nitrogen (MFN) and calculated endogenous urinary nitrogen (EUN) and dermal losses, minimum dietary CP required to meet maintenance requirement was estimated to be 6.12, 6.05, and 5.97% in juveniles, sub-adults, and adults, respectively. Restriction of concentrates resulted in decreased (P < 0.05) digestibility of DM and GE, but the diet still supplied adequate amounts of DE and CP to fulfill estimated requirements of energy and protein during the period of experimentation. Thus, the concentrates portion of the diets of captive Asian elephants should be fed in a restricted way so as to reduce the intake of excessive calories and the potential risk of obesity.