Ileal Digestibility Coefficients Research Articles

Ileal digestibility of fat and fatty acids in polar foxes (Alopex lagopus L.) fed diets used during the reproductive period

This study evaluates apparent ileal digestibility of fat and fatty acids in ‘end-to-end’ ileorectal anastomosed blue foxes fed diets used over the reproduction (diets A1 and B1) and lactation (diets A2 and B2) periods on two farms (A and B). The experimental diets A1 and A2 were composed of different animal offal and cereals, while diets B1 and B2 contained beef offal and barley. Diets B1 and B2 had a higher content of fat (315.4 and 361.0 g kg−1), SFA (164.3 and 185.7 g kg−1) and MUFA (116.7 and 133.6 g kg−1), while diets A1 and A2 contained more PUFA (13.1 and 30.4 g kg−1). Significantly higher (P < 0.05) values of ileal fat digestibility coefficients (97.33 and 96.92%), SFA (97.24 and 95.96%) and MUFA (98.69 and 98.87%) were found in diets B, whereas PUFA were better absorbed from diets A1 and A2 (85.54 and 94.42%).

Digestibilidade ileal e perdas endógenas de aminoácidos de dietas com óleo de soja para suínos em crescimento

Este trabalho foi conduzido para avaliar o efeito de diferentes níveis de óleo de soja sobre as perdas endógenas e a digestibilidade ileal aparente e verdadeira dos aminoácidos em dietas para suínos em crescimento. Foram testadas quatro dietas isoprotéicas, à base de milho e farelo de soja, formuladas segundo as exigências para essa fase e suplementadas com níveis crescentes de óleo de soja (0,0; 1,5; 3,0; 4,5%) e 0,25% de óxido crômico como indicador de indigestibilidade. Dezesseis suínos canulados (cânula T simples), com 48,0 ± 6,0 kg, foram distribuídos em um delineamento em blocos casualizados, com base no peso dos animais. Não houve efeito dos níveis óleo de soja sobre os coeficientes de digestibilidade ileal aparente de glutamato, glicina, arginina, alanina, prolina, tirosina, histidina e lisina. Observaram-se efeito linear da suplementação com níveis de óleo de soja nos coeficientes de digestibilidade ileal aparente e verdadeira de serina e treonina e efeito quadrático da suplementação de óleo de soja sobre os coeficientes de digestibilidade ileal aparente e verdadeira de valina, fenilalanina, total de aminoácidos não-essenciais e total de aminoácidos essenciais. Os coeficientes de digestibilidade ileal verdadeira de arginina e tirosina também apresentaram efeito quadrático da suplementação de óleo de soja. Melhores valores de digestibilidade ileal aparente e verdadeira dos aminoácidos não-essenciais e essenciais são obtidos com adição de 2,8 a 3,0% de óleo de soja à dieta de suínos em crescimento.

Utilização de nutrientes de dietas contendo mananoligossacarídeo e/ou complexo enzimático para frangos de corte

Avaliaram-se a digestibilidade ileal e a retenção de alguns nutrientes e os valores de energia de dietas contendo mananoligossacarídeo (MOS) e/ou complexo enzimático (CE) para frangos de corte. Foram utilizadas 275 aves em delineamento em blocos ao acaso e arranjo fatorial 2 x 2 + 1, com dois níveis de MOS (0 e 0,1%), dois níveis de complexo enzimático (0 e 0,05%) e uma dieta controle positivo com antibióticos. O óxido crômico (0,5%) foi adicionado às dietas para estimativa do fator de indigestibilidade. O experimento teve início quando as aves completaram 13 dias de idade; a coleta de excretas foi realizada do 20º ao 22º dia e a de digesta, no 23º dia de idade das aves. A interação MOS × CE foi significativa para a retenção de PB e P e de energia metabolizável aparente (EMA), cujos valores foram maiores nas dietas com MOS e CE. A inclusão do CE melhorou a retenção de MS e os coeficientes de digestibilidade ileal de MS, PB, Ca e P na retenção de cálcio e nos valores de energia digestível com a inclusão de mananoligossacarídeo. Os coeficientes de digestibilidade ileal da MS, a retenção de MS, PB, Ca e P e os valores de energia digestível e de EMA das dietas contendo MOS e/ou CE foram superiores aos obtidos com a dieta contendo antibióticos.

Impact of wheat grinding and pelleting in a wheat–rapeseed meal diet on amino acid ileal digestibility and endogenous losses in pigs

The purpose of the current experiment was to investigate the impacts of grinding and pelleting procedures applied to wheat in a wheat–rapeseed meal diet on the coefficients of standardized ileal digestibility, i.e., apparent digestibility corrected for basal endogenous losses (CSID), and true ileal digestibility, i.e., apparent digestibility corrected for total endogenous losses (CTID), of nitrogen (N) and amino acids (AA) in pigs. Ileal digestibility was measured by collecting digesta from pigs fitted with ileorectal anastomoses. Four diets, involving four technological treatments applied to wheat, were compared in vivo according to a 4 × 4 Latin square design (four pigs each fed four diets during four successive periods of 1 week). The technological treatments of wheat were two grinding procedures and two pelleting processes. Wheat was ground to obtain mean flour particle sizes of 1000 and 500 μm, leading after mixing with rapeseed meal and minerals-vitamins premix to the first and second diets named “coarse” and “fine”, respectively. Part of the 500 μm wheat flour was pelleted through dies of same screen diameter (4 mm) but different thicknesses, 16 and 20 mm, inducing a low and high compression ratio, leading after mixing with rapeseed meal and premix to the third and fourth diets named “LCR” and “HCR”, respectively. Basal endogenous losses were determined by feeding a protein-free diet during the 5th week of the experiment. Total endogenous losses were measured by way of the isotopic dilution method using 15N-labeled wheat and rapeseed meal. Decreasing wheat particle size from 1000 to 500 μm improved (P<0.05) the coefficient of ileal digestibility of dietary energy (0.707 versus 0.665), organic matter (0.718 versus 0.677) and dry matter (0.681 versus 0.645), but neither AA CSID nor N retention. The pelleting processes did not further increase (P>0.10) energy or organic matter digestibility but improved (P<0.05) N and AA CSID (0.785 versus 0.759 for N and 0.725 versus 0.679 for lysine, with HCR versus fine diet, respectively). Pelleting wheat flour at higher compression ratio (HCR versus LCR diet) was more efficient to improve dietary N and AA digestibility values due to a significant decrease in ileal specific, i.e., total minus basal, N and AA endogenous losses (P<0.05) associated with an increase in CTID. It is concluded that pelleting wheat fine flour at high compression ratio allows maximizing AA digestibility and availability of a wheat–rapeseed meal diet.

A dynamic model of digestion and absorption in pigs

The paper describes and evaluates the construction of a mathematical model to study the kinetics of digestion and absorption in growing pigs. The core of the model is based on a compartmental structure, which divides the gastro-intestinal tract into four anatomical segments: the stomach, two parts of the small intestine and the large intestine. Within the large intestine, a microbial sub compartment is also considered. In each of these segments, the major organic nutrients are considered: dietary protein, endogenous protein, amino acids, non-amino acid and non-protein nitrogen, lipids, fatty acids, starch, sugars and dietary fibre. Besides a chemical description of the feed, the model further requires information about daily dry matter intake and feeding frequency. Flows of nutrients from one anatomical segment to the next are assumed to be mass action processes, whereas degradation and absorption are described as enzymatic processes and are therefore represented by saturation kinetics. The model also proposes a basic concept for integrating effects of anti-nutritional factors into a mechanistic framework. The total number of pools is 38 and their rates of change are described by differential equations on the principle of mass conservation. Parameterization of the equations describing secretion and absorption is derived from literature values, whereas parameters for degradation are empirically adjusted to ileal and faecal digestibility coefficients determined for 24 diets highly variable in chemical composition. A sensitivity analysis has revealed that the prediction of nutrient digestibility is insensitive to affinity constants and moderately sensitive to maximum velocities for nutrient degradation. Predictions of apparent protein digestibility and endogenous nitrogen loss are especially sensitive to a reference level of dietary fibre in the last segment of the small intestine. The reference quantity of organic matter, which is related to the transit in the large intestine, has a large impact on the predicted apparent digestibility of dietary fibre and energy. The model predicts coefficients of crude protein and energy digestibility with good accuracy across 65 diets from 11 studies. Lipid is predicted less accurately. Predictions of endogenous protein losses in response to increased dietary fibre are compared with results from eight studies including 39 diets and it is concluded that the predictions are moderately satisfactory. The model predicts the pattern of organic matter flow at the terminal ileum and the appearance of nutrients in the portal blood with fairly good accuracy. The validation of kinetics of nutrient absorption has highlighted the necessity for future models to include a representation of gut wall metabolism in order to validate digestive models at their most valuable terminal output. Full utilization of the model as a predictive tool can be expected when it is combined with a metabolism model.

Evaluating standardized ileal digestibility of amino acids in growing pigs

The ileal digestibility coefficient (CSID) of amino acids (AA) and crude protein (CP) in 40 feedstuffs for growing pigs were determined with the protein-free (PF) and enzyme-hydrolyzed casein (EHC) methods. The 40 feedstuffs that were used earlier were 10 samples of cereals and cereal by-products, 12 samples of legumes, 6 samples of animal protein feedstuff and 12 samples of oil seed meals. Six growing pigs (initial body weight of 35 ± 1.5 kg), fitted with T-cannula at the terminal ileum, were randomly allocated to either a PF or a EHC diet according to a crossover design during two ileal digesta collection periods. In each period, pigs were adjusted to the experimental diets for 5 days. On days 6 and 8, ileal digesta were collected continuously for 24 h to determine ileal endogenous AA and CP losses. Pigs fed the EHC diet had a higher ileal flow of endogenous CP and of most of AA (P<0.05) than pigs fed the PF diet. Among the ileal endogenous AA flows (g/kg dry matter intake for pigs), methionine excretion was the lowest in pigs (0.09 and 0.25 g/kg dry matter intake) fed the PF and EHC diet, respectively, whereas glutamate (1.83 g/kg dry matter intake) and proline (1.22 g/kg dry material intake) excretion were the highest in pigs fed the EHC and the PF diet, respectively. Endogenous losses of CP and AA determined in the current study and previously published data on apparent ileal digestibility [Yin, Y.L., Huang, R.L., Zhong, H.Y., Chen, C.M., Li, T.J., Pan, Y.F., 1993. Nutritive value of feedstuffs and diets for pigs: 1. Chemical composition, apparent ileal and fecal digestibilities. Anim. Feed Sci. Technol. 44, 1–27] were used to calculate CSID coefficients. For most cereals and cereal by-products, the CSID coefficients of CP determined by the EHC method were higher than those determined by the PF method. Arginine, lysine, methionine, threonine, valine, alanine, aspartate, glutamate, glycine, proline and serine in some cereals and cereal by-products; methionine, valine, alanine and proline in some legumes; and methionine, alaline and proline in some oilseed meals had higher CSID determined by the EHC method than the PF method indicating that there are methodological differences when evaluating the CSID of feed ingredients.

True ileal protein and amino acid digestibilities in wheat dried distillers’ grains with solubles fed to finishing pigs

As wheat dried distillers’ grains with solubles (WDDGS) become increasingly available in western Canada, there is currently a great interest in evaluating its potential as a feedstuff for pigs. Thus, the apparent, standardized and true ileal crude protein (CP) and amino acid (AA) digestibilities in WDDGS were determined. Six finishing pigs (∼82 kg initial BW) fitted with a simple T-cannula at the distal ileum were fed diets containing either 400 g/kg WDDGS or 50 g/kg casein as the sole protein source in a simple crossover design. Chromic oxide (3 g/kg) and acid insoluble ash (AIA, 10 g/kg) were included in the diets as indigestible markers. The casein diet was used to quantify endogenous protein and AA losses. Standardized ileal CP and AA digestibilities were estimated using published basal endogenous protein and AA losses. Pigs were acclimatized to their diets for 5 days followed by a continuous 12-h digesta collection period on days 6 and 7. Ileal CP and AA digestibility coefficients obtained with AIA as a marker were similar to those obtained with Cr 2O 3 (P>0.05). Endogenous losses, coefficient of apparent ileal digestibility and coefficient of true ileal digestibility in g/kg dry matter intake were 22.81, 0.64 and 0.79 for CP, 0.94, 0.73 and 0.89 for arginine, 0.41, 0.68 and 0.79 for histidine, 0.46, 0.73 and 0.81 for isoleucine, 0.59, 0.78 and 0.83 for leucine, 0.54, 0.36 and 0.56 for lysine, 0.10, 0.71 and 0.77 for methionine, 0.32, 0.82 and 0.86 for phenylalanine, 0.89, 0.62 and 0.78 for threonine and 0.59, 0.71 and 0.79 for valine. Of all the essential AA analyzed, lysine had the lowest digestibility value, which suggests reduced availability of this AA.

Effects of a dietary organic acid mixture and of dietary fibre levels on ileal and faecal nutrient apparent digestibility, bacterial nitrogen flow, microbial metabolite concentrations and rate of passage in the digestive tract of pigs

Six 34-kg barrows were fitted with a post-valve T-caecum cannula and assigned to six dietary treatments according to a 6 × 5 change-over design to study how a mixture of formic acid, sorbate, and benzoate (0 or 8.4 g/kg feed) influences apparent ileal and faecal digestibility coefficients, bacterial nitrogen (N) flow, microbial metabolite concentrations, and passage rate in pigs fed isoenergetic diets with medium, high, or very high fibre content (neutral-detergent fibre (NDF): 199, 224, and 248 g/kg dry matter, respectively). These barley and soya-bean meal based diets contained 0, 75, and 150 g/kg barley fibre (NDF: 577 g/kg) and 0, 8, and 16 g/kg rapeseed oil, respectively. The dietary organic acid mixture improved the apparent ileal digestibility of 14 of the 17 amino acids analysed (P < 0.05). Increasing levels of dietary fibre linearly decreased the apparent ileal digestibility of six of the 17 amino acids analysed (P < 0.05). Ileal flows of bacterial N and amino acids as assessed on the basis of purine flow were decreased by the dietary organic acid mixture (P < 0.05) but were not affected by dietary fibre level (P>0.05). As assessed on the basis of diaminopimelic acid flow, bacterial N flow was increased by both the dietary organic acid mixture and increased dietary fibre levels (P < 0.05). The dietary organic acid mixture reduced the concentration of lactic acid and increased that of acetic acid in ileal digesta (P < 0.05), while dietary fibre levels had a quadratic effect on concentrations of acetic, propionic, and butyric acid (P < 0.05). The mean retention time of Co (solute marker) and Yb (particle marker) in the large intestine decreased in a linear manner by increasing dietary fibre levels (P < 0.05) but was not affected by the dietary organic acid mixture (P>0.05). The results show that a dietary organic acid mixture has a positive effect on the apparent ileal digestibility of most amino acids irrespective of dietary fibre levels. This could be at least partly related to changes in bacterial N flow in the ileum. However, different bacterial markers showed opposite effects on bacterial N flow, which makes it questionable to use a constant bacterial marker / bacterial N ratio to estimate bacterial N flow. Increasing levels of dietary fibre had negative effects on the apparent ileal amino acid digestibilities and shortened the mean retention time of digesta in the large intestine.

Ileal digestibility of amino acids in co-extruded peas and full fat canola for growing pigs

An experiment was conducted to determine coefficients of ileal apparent digestibility (CIAD) and ileal true digestibility (CITD) of amino acids (AA) in co-extruded peas and full fat canola products differing in canola type (standard and heated) and days elapsed from mixing to extrusion (D-0 and D-10). Heated canola contained a blend of standard canola and 80 g/kg of heated canola as defined by Canadian Grain Commission (CGC) grading standards. Peas were mixed with either standard or bin heated canola seeds (50:50, w/w) and a part of each mixture was extruded immediately (D-0) and the other part later (D-10). Four diets were formulated to contain each of the four products (650 g/kg) as the sole source of AA. A fifth diet containing casein (50 g/kg) was used to estimate basal endogenous loss of nitrogen and AA. Chromic oxide (Cr 2O 3) and HCl insoluble ash (HCl-IA) were included in all diets as indigestible markers. Diets were fed to 5 growing barrows, average BW 66.3 ± 4.9 kg, and fitted with a simple T-cannula at the distal ileum according to 5 × 5 Latin square design. Experimental periods lasted 6 d and ileal digesta was collected in 12-h periods on D-5 and D-6. Digestibility values obtained with the two markers were pooled as they were established to be similar. There was an interaction (P<0.05) between canola type and days elapsed to extrusion in CIAD and CITD of crude protein (CP) such that extrusion after 10-d storage increased CIAD and CITD of CP of the diets containing heated canola only. An interaction (P<0.05) between canola type and days elapsed to extrusion in AA digestibility was observed in CIAD of aspartic acid and CITD of aspartic acid and glutamic acid. Extrusion after 10-d storage increased CIAD of aspartic acid and CITD of aspartic acid and glutamic acid of the diets containing heated canola only. Except for methionine and proline, extrusion of peas and canola mixture after 10-d storage increased (P<0.05) CIAD and CITD of AA regardless of canola type. The mean CIAD and CITD for indispensable AA ranged from 0.666 to 0.767 and from 0.725 to 0.832, respectively. In conclusion, canola type had no affect on AA digestibility of co-extruded peas and full fat canola products; however, extruding the mixture after 10-d storage increased AA digestibility regardless of the canola type indicating quality improvement over time.

Influence of soaking, fermentation and phytase supplementation on nutrient digestibility in pigs offered a grower diet based on wheat and barley

AbstractThe effects of 1-h soaking, fermentation and phytase supplementation of a pig diet based on wheat and barley on ileal and total tract apparent digestibility in growing pigs fitted with a post valve T-caecum (PVTC)-cannula were studied. Eight animals in a two-period change-over design were used, subjecting four animals to each treatment (dry, soaked, microbial phytase supplemented or fermented diet). Acid insoluble ash was used as an indigestible marker for calculating apparent digestibility coefficients. Fermentation improved (P&lt;0·05) the ileal apparent digestibility coefficients of organic matter (OM), nitrogen and amino acids, while there was no effect of 1-h soaking and phytase supplementation. The total tract apparent digestibility coefficient of OM was also improved by fermentation. The ileal apparent digestibility coefficient of phosphorus (P) was higher for fermentation (P&lt;0·05) than for dry food and 1-h soaking. The total tract apparent digestibility coefficient of P was higher (P&lt;0·05) for treated food (soaked, fermented and supplemented with microbial phytase) compared with dry food. Fermentation improved (P&lt;0·05) the ileal apparent digestibility coefficient of calcium compared with dry and soaked food, and had no effect on the total tract apparent digestibility coefficient of calcium. Food inositol phosphates were affected by treatment (P&lt;0·05), with a reduction of P bound to inositol hexaphosphate (IP6) of 10% in the 1-h soaked food and of 80% in the fermented food. Degradation of IP6in the gastro-intestinal tract of the animals was lower in the fermented food than in the other treatments. The content of neutral-detergent fibre in the food was reduced (P&lt;0·05) in the soaked and fermented food by 4% and 14%, respectively, compared with the dry food. In conclusion, fermentation of food can improve digestibility of OM, degrade IP6and increase ileal digestibility of phosphorus, nitrogen and amino acids.

Endogenous ileal losses of nitrogen and amino acids in pigs and piglets fed graded levels of casein

In order to determine ileal losses of nitrogen (N) and amino acids (AA) and the coefficients of apparent and true ileal digestibility (AID, TID) of N and AA from casein in piglets and pigs, two experiments were conducted. In Experiment 1, 24 piglets were used. The piglets were weaned at 17 days of age, weighing 6.4 kg and cannulated at terminal ileum. Ileal digesta was collected at 28 – 29 and 35 – 36 days of age in period 1 and 2, respectively. Feed intake was 150 and 300 g · d−1 during the first and second period. In Experiment 2, 16 castrates weighing 52.5 kg and cannulated at terminal ileum were used. The intake level of digestible energy was 2.5 times their maintenance requirement. The experiment lasted 7 days and ileal digesta was collected on day 6 – 7. Treatments consisted of four levels of N from casein: 8, 16, 24 and 32 g N · kg−1 feed, respectively. Results showed that N level did not increase N or AA ileal losses. In piglets, N and AA ileal losses were similar between periods, except for period 2, where losses per kg DMI were about 47 and 64% higher for glycine and proline, respectively (p < 0.05). When ileal losses from pigs and piglets were compared, piglets had higher (p < 0.05) ileal losses of N and AA (excepted glutamic acid and alanine). A lower (p < 0.05) AID was observed in piglets in period 2 for N, methionine, glutamic acid, glycine and proline. With exception of glycine in pigs, all values for TID of N and AA of casein were superior to 0.90. Piglets had higher TID of N, leucine, isoleucine, valine and phenylalanine. These results showed that piglets have higher ileal losses than pigs.

Ileal amino acid digestibility of some novel dietary protein sources for growing chickens

AbstractThe apparent ileal digestibility coefficients of amino acids in five high‐protein ingredients (casein, isolated soyprotein, maize gluten meal, spray‐dried bovine plasma (SBP) and spray‐dried porcine plasma (SPP)) and soybean meal were determined using 3‐week‐old broiler chickens. The amino acids in casein were highly digestible. Isolated soyprotein was also well digested by the birds, but the digestibility coefficients of all amino acids in isolated soyprotein were lower (P &lt; 0.05) than those in casein. The amino acid digestibility coefficients in isolated soyprotein were greater (P &lt; 0.05) than those in soybean meal, which may be reflective of reduced concentrations of anti‐nutritive factors, particularly indigestible oligosaccharides. The digestibilities of amino acids in maize gluten meal were higher (P &lt; 0.05) than those in soybean meal, except for the digestibilities of arginine, histidine, threonine and aspartic acid, which were similar (P &gt; 0.05) between the two protein sources. The ileal digestibilities of all indispensable amino acids in SBP and SPP were lower (P &lt; 0.05) than those in casein and isolated soybean meal but higher (P &lt; 0.05) than those in soybean meal. No differences (P &gt; 0.05) were observed in the digestibility of amino acids between SBP and SPP. The overall mean amino acid digestibility coefficients of casein, isolated soyprotein, soybean meal, maize gluten meal, SBP and SPP were 0.955, 0.888, 0.823, 0.849, 0.860 and 0.856 respectively. Copyright © 2006 Society of Chemical Industry

Biological response of broiler chickens fed peas (Pisum sativum L.) expressing the bean (Phaseolus vulgaris L.) α‐amylase inhibitor transgene

AbstractThe nutritive value of transgenic peas expressing an α‐amylase inhibitor (α‐Ai1) was evaluated with broiler chickens. The effects of feeding transgenic peas on the development of visceral organs associated with digestion and nutrient absorption were also examined. The chemical composition of the conventional and the transgenic peas used in this study were similar. In the two feeding trials, that were conducted normal and transgenic peas were incorporated into a maize–soybean diet at concentrations up to 500 g kg−1. The diets were balanced to contain similar levels of apparent metabolisable energy (AME) and amino acids. In the first trial, the birds were fed the diets from 3 to 17 days post‐hatching and with levels of transgenic peas at 250 g kg−1 or greater there was a significant reduction in body weight but an increase in feed intake resulting in deceased feed conversion efficiency. In the second trial, in which the birds were fed diets containing 300 g kg−1 transgenic peas until 40 days of age, growth performance was significantly reduced. It was also demonstrated that the ileal starch digestibility coefficient (0.80 vs 0.42) was significantly reduced in the birds fed transgenic peas. Determination of AME and ileal digestibility of amino acids in 5‐week‐old broilers demonstrated a significant reduction in AME (12.12 vs 5.08 MJ kg−1 DM) in the birds fed the transgenic peas. The AME value recorded for transgenic peas reflected the lower starch digestibility of this line. Ileal digestion of protein and amino acids was unaffected by treatment. Expression of α‐Ai1 in peas did not appear to affect bird health or the utilisation of dietary protein. However, the significant reduction in ileal digestion of starch in transgenic peas does reduce the utility of this feedstuff in monogastric diets where efficient energy utilisation is required. Copyright © 2006 Society of Chemical Industry

Influence of β-glucanase supplementation on the metabolisable energy and ileal nutrient digestibility of normal starch and waxy barleys for broiler chickens

The influence of β-glucanase supplementation on the nitrogen-corrected apparent metabolisable energy (AME n ) and apparent ileal digestibility (AID) coefficient of starch, protein and amino acids in four barley cultivars that differed in fibre contents (hulls) and starch characteristics (waxiness), was investigated. The cultivars included a conventional, hulled normal starch barley (C-NS), a hull-less normal starch barley (H-NS) and two hull-less waxy barleys (H-W1 and H-W2). The AME n of the two hull-less waxy cultivars were determined to be lower (P<0.05) than those of C-NS and H-NS. The AME n of the C-NS and H-NS barleys, irrespective of the presence or lack of hulls, were similar (P>0.05). β-Glucanase supplementation improved the AME of all barley cultivars, but the magnitude of response was markedly greater (P<0.05) in waxy genotypes compared to the normal starch genotypes. The cultivar type had no influence (P>0.05) on the AID of protein and most amino acids. Enzyme supplementation improved (P<0.001) the AID of protein and amino acids in all barley cultivars. The average AID of the 18 amino acids was increased by 11.9% by enzyme addition, ranging from 5.1% for methionine to 18.1% for threonine. These data suggest that starch characteristics and type of β-glucan may influence the available energy in barley for broiler chickens. These characteristics may be equally or more important than fibre contents in determining the feeding value of barley for poultry.

Adição de complexo multienzimático em dietas à base de soja extrusada: valores energéticos e digestibilidade de nutrientes em pintos de corte

O experimento foi realizado com o objetivo de avaliar os efeitos da adição de complexo multienzimático (CM) e do nível de processamento da soja sobre os valores energéticos e os coeficientes de digestibilidade dos nutrientes de rações para pintos de corte. Foram utilizados 288 pintos de corte machos da linhagem Avian Farms, com oito dias de idade, em arranjo fatorial 3 x 2 (rações à base de soja extrusada subprocessada, normal e superprocessada, suplementadas ou não com complexo multienzimático), totalizando seis tratamentos, com oito repetições de seis aves por unidade experimental. As excretas foram coletadas e pesadas durante cinco dias consecutivos, utilizando-se os métodos de coleta total e de coleta ileal. A adição do CM (protease, amilase e celulase) promoveu aumento médio dos coeficientes de digestibilidade ileal aparente de matéria seca, proteína, energia e gordura das dietas de 4,8; 1,3; 4,8 e 6,0%, respectivamente. Entretanto, os maiores aumentos nos valores de digestibilidade ileal proporcionados pelo CM foram obtidos com as rações contendo soja extrusada subprocessada: 10,7% MS, 4,2% PB, 11,4% EB e 17,6% gordura. A adição do CM melhorou a digestibilidade ileal de FDN, FDA e HEM, em média, 10,60; 23,05 e 6,39%, respectivamente. As aves alimentadas com dietas contendo soja extrusada normal apresentaram maiores coeficientes de digestibilidade ileal dos nutrientes e valores de EM que aquelas alimentadas com sojas extrusadas sub e superprocessadas.

Effects of supplementing pig diets with tryptophan and acidifier on protein digestion and deposition, and on brain serotonin concentration in young pigs

The objective of the study was to find out whether feeding acidifying preparation with diets containing crystalline tryptophan (Trp) affects availability of this amino acid for protein and serotonin (5-HT) synthesis in young pigs. Two experiments were performed. Supplementation of Trp-deficient diet with 3 g/kg of acidifier (A) (mixture of phosphoric, citric and fumaric acids) did not affect the coefficients of ileal apparent digestibility (CIAD) of protein and protein-bound amino acids except CIAD of Trp which was increased from about 0.65 to 0.73. In pigs of initial body weight 16 kg, the increase of digestible dietary Trp level from 0.77 to 1.39 and 1.85 g/kg improved growth performance, nitrogen retention and utilization of nitrogen absorbed, while the increase from 0.77 to 1.39 g/kg enhanced 5-HT concentration in all six analyzed brain structures. Supplementation with A did not affect blood Trp level in animals fed on Trp-deficient diet while it decreased it considerably on diet supplemented with Trp to 1.85 g/kg. Feeding A affected 5-HT metabolism: decreased its level in five of six brain structures in pigs fed on Trp-deficient diet, changed 5-HT metabolite 5-hydroxy-indolo-3-acetic acid (5-HIAA) and 5-HIAA/5-HT ratio, and modified response of 5-HT to Trp supplementation. It is concluded that feeding A both with Trp-deficient and Trp-supplemented diets has positive net effect on growth and protein deposition in pigs while it seems to affect negatively 5-HT synthesis and, probably, accelerates its turnover. The mechanism of this action is not known, and it was not proved that it is related to destructive effect of acids on crystalline Trp.

Effect of feeding schedule on apparent energy and amino acid digestibility by growing pigs

An experiment was conducted to investigate the effects of feeding schedule on dry matter (DM), gross energy (GE), crude protein (CP), and amino acid (AA) digestibility by growing pigs. Six growing castrates (initial body weight: 40.5 ± 2.25 kg) were equipped with a T-cannula in the distal ileum and allotted to a repeated 3 × 3 Latin square design with three animals and three periods in each square. A maize–soybean meal based diet (181 g CP/kg) was formulated and fed to the pigs in three different feeding schedules; i.e., one meal per day, two meals per day, or free access to feed. Pigs fed one or two meals per day were allotted a daily amount of feed equivalent to three times the maintenance energy requirement. Fecal and ileal samples were collected from all pigs in each period. The coefficients of ileal apparent digestibility (CIAD) for DM, GE, CP, and AA were calculated as were the coefficients of total tract apparent digestibility (CTTAD) of DM and GE. Results of the experiment showed that there were no differences in the CIAD for DM, GE, or for any of the AA among the three feeding schedules. In contrast, pigs given free access to the diet had lower (P<0.002) CTTAD for DM and GE compared with pigs fed a restricted amount of feed either once or twice daily. Therefore, the concentration of digestible energy in the diet was lower if calculated from pigs given free access to the diet compared with pigs fed the diet once or twice daily (14.38 MJ/kg versus 14.83 MJ/kg and 15.13 MJ/kg). It is concluded that the feeding schedule does not influence the CIAD for DM, GE, CP, or AA by pigs. Therefore, any of the three feeding schedules that were used in the current experiment may be used in experiments aimed at measuring CIAD in pigs. However, if the CTTAD of DM and GE are measured, it is recommended that pigs are given free access to feed.

Total and ileal digestible tryptophan contents of feedstuffs for broiler chickens

AbstractReliable values of total and digestible tryptophan in components of feed formulation matrices are needed because tryptophan is often the third limiting amino acid in practical poultry diets. However, tryptophan is oxidatively destroyed during acid hydrolysis in routine amino acid analysis and its determination requires a separate analytical procedure. The variability in contents and apparent ileal digestibility for 6‐week‐old broiler chickens of tryptophan in 74 samples representing 24 feedstuffs are presented in this paper. The average ileal tryptophan digestibility coefficient in wheat was 0.83, in sorghum and triticale 0.75, maize 0.71, soybean meal 0.84, sunflower meal 0.81, canola meal 0.78 and cottonseed meal 0.75. Among the grain legumes, tryptophan in lupins was better digested than that in chickpeas, fababeans and field peas. Among the animal protein meals, the tryptophan digestibility coefficients in fish meal (0.77) and blood meal (0.84) were substantially higher than those in meat meal (0.62), meat‐and‐bone meal (0.63) and feather meal (0.52). Marked variations in tryptophan digestibility were also observed among samples of fish meal, meat‐and‐bone meal and meat meal, highlighting significant batch‐to‐batch differences. For most feedstuffs, considerable variability was observed in the tryptophan concentrations, but such variations were not reflected in digestibility coefficients. Copyright © 2006 Society of Chemical Industry

The effect of extrusion cooking of different starch sources on the in vitro and in vivo digestibility in growing pigs

A study with a total of 36 crossbred castrate male pigs (37.5 ± 0.6 kg) fitted with a simple T-cannula was carried out. The effect of extrusion cooking of barley, peas and a mixture (4:1) of potato starch and wheat bran (PSWB) on the coefficients of ileal (CIAD) and total tract apparent digestibility (CTTAD) according to a 3×2 factorial design was determined. The starch digestion profile of carbohydrate-containing ingredients was described using an in vitro setup based on the Englyst procedure for nutritional classification of starch. Extrusion cooking increased the proportion of rapidly digestible starch (RDS), and reduced the proportion of slowly digestible starch (SDS) and resistant starch (RS), and an in vitro digestion profile up to 8 h demonstrated major differences in the rate and extent of digestion of the raw carbohydrate sources, while the digestion profiles of the extruded products were almost identical. In vivo, extrusion cooking caused a big increase in the CIAD of starch and total carbohydrates of the diets containing legume and root starches; for PSWB, the CIAD of starch increased from 0.32–0.47 to 0.98, and for peas the CIAD of starch increased from 0.80 to 0.91 when the starch containing ingredient was extruded. The difference in CIAD between raw (0.93) and extruded barley (0.99) was not significant. Whereas extrusion cooking had a strong influence on the CIAD of crude protein with the barley and pea diets, only marginal effects were seen for the PSWB diets, where most protein was in the form of added casein. Extrusion cooking increased significantly the CTTAD of dry matter, organic matter and crude protein of the pea and PSWB diets, but not of barley. Overall, the experiment reported shows that the effect of extrusion cooking on nutritional value and amounts of substrate entering the large intestine using carbohydrate-rich feedstuffs for growing pigs is dependent on carbohydrate source.

The effect of date fibre supplemented with an exogenous enzyme on the performance and meat quality of broiler chickens

1. Two experiments were conducted to evaluate the use of date fibre as a partial replacement of maize as a source of energy for growing broiler chicken. In experiment 1, date fibre was given alone to determine apparent metabolisable energy (AME) and apparent ileal digestibility of amino acids and crude fibre. 2. Date fibre had lower AME content (8·7 vs 13·6 MJ/kg) and apparent ileal digestibility coefficients for dry matter (0·35 vs 0·83), crude fibre (0·20 vs 0·54) and amino acids. 3. Based on the results of experiment 1, a growth study was conducted to test the effect of exogenous enzymes on the nutritive value of date fibre (experiment 2). 4. Three date fibre contents (5, 10 and 15%) with and without enzyme supplementation were evaluated. Daily feed intake, body weight gain and feed conversion ratio were measured. At the end of experiment 2, 160 birds were randomly selected and slaughtered to evaluate carcase and meat quality traits as well as measuring ileal viscosity. 5. Substitution of maize by 10 and 15% date fibre significantly depressed AME. Enzyme supplementation did not improve crude fibre digestibility. The inclusion of date fibre in the diets except at 5% decreased average daily gains, feed intake and feed conversion ratio. 6. Addition of date fibre caused a significant increase in the weights of total digestive tract, pancreas and caecum. Addition of date fibre or the exogenous enzyme had no significant effect on carcase or meat quality characteristics. 7. Date fibre increased ileal digesta viscosity compared to the control. Addition of the exogenous enzyme decreased the viscosity of the basal diets but had no effect on the date fibre diets. 8. This study indicated that date fibre can be included at levels of 5% in broiler diets without affecting performance.