True Digestibility Coefficients Research Articles

True digestibility of the essential amino acids of high-protein sunflower meals by balanced experiments with intact and caecectomized birds from Gallus species

Abstract. Using adapted methods for balanced experiments with poultry, the true digestibility coefficients of the essential amino acids of two high protein sunflower meals – 40+® and 47® have been established. The true digestibility coefficients by using two methods – with intact and randomized (caecectomized) birds have been compared. Six birds were tube fed and six – feed deprived for both of the fodders. The amino acids were established with amino analyzer AAA-881 after preliminary HCl hydrolysis. The mean digestibility of sunflower meal 40+® is higher in intact (88.11 versus 85.73 of sunflower meal 47®) compared to randomized birds (87.20 versus 85.46 of sunflower meal 47®). The differences by lots are statistically significant only in intact birds. The authors recommend for practical needs to use the average true digestibility coefficients between both meals, established with randomized birds (ileal digestibility).

Age and Calcium Sources in Laying Hen Feed Affect Calcium Digestibility

The apparent calcium (Ca) digestibility coefficient (ADC) and true digestibility coefficient (TDC) of different inorganic calcium sources were determined in laying hens of different ages. Three Ca digestibility tests were carried out, each assessing 240 Lohmann Brown lineage laying hens distributed in a completely randomized design. Nine dietary treatments were arranged in a 3 × 3 factorial design consisting of three ages (40, 50 and 70 weeks) × three Ca (dicalcium phosphate (DCP) sources, fine (FL) and coarse (CL)) limestone, comprising eight replicates per treatment of six birds per experimental unit. Regarding the DCP, the ADC was higher (P as 0.889, 0.613 and 0.712, respectively. No effect (P > 0.05) of age on the ADC was noted for either FL or CL. Comparing Ca sources, DCP exhibited a higher (P 0.05). Endogenous loss values of 790, 860 and 930 mg·kg-1 of consumed dry matter were observed at 40, 50 and 70 weeks, respectively. For the TDC, no interaction (P > 0.05) was observed between Ca sources and bird age. The highest TDC value (P > 0.05) was found in birds fed DCP (0.786) followed by FL (0.637) and CL (0.534). In addition, birds at 40 weeks of age (0.714) exhibited higher TDC values (P

Digestibility and bioavailability of organic calcium sources for European quail

The objective of this study was to determine the apparent and true digestibility coefficients and relative bioavailability of charru mussel, maçunim (Anomalocardia brasiliana) and oyster shells as organic calcium sources for meat quail. In the digestibility trial, 240 quail were distributed in a completely randomized experimental design with five diets (calcitic limestone, calcium carbonate and three marine calcium sources), five replicates and eight quails per experimental unit. The relative bioavailability of calcium was determined by the standard-curve and slope ratio methods in a growth trial in which 288 European quail were distributed in completely randomized experimental design. Treatments consisted of basal diet with a low calcium concentration (0.166%) that was supplemented with two levels of calcium (0.342% and 0.684%) derived from different calcium sources. The apparent and true digestibility coefficients of calcium from charru mussel-, maçunim- and oyster-shell meals for meat quail were 91.85 and 92.04%; 91.71 and 91.90%; and 89.39 and 89.63%, respectively. The relative bioavailability of calcium from charru mussel-, maçunim- and oyster-shell meals obtained using standard-curve and slope ratio methods were 133.22 and 119.18%; 140.05 and 113.69%; and 141.73 and 106.22%, respectively, allowing the use of these organic calcium sources in diet formulations for meat quail.

Установяване на обменната енергия и истинската смилаемост на протеина на екструдирани вторични продукти от хлебопроизводството (хлебни отпадъци) при балансови опити с птици

Using methods for balance experiments, the apparent (AMEn), the true (TMEn) metabolizable energy (0-n balance corrected) and the coefficient of true digestibility of the nitrogen/protein (CTDP) of extruded bread wastes have been studied. The chemical composition of the dry matter of the fodder was, as follow (in %): crude protein – 12.28; crude fats – 1.34; crude fiber – 2.28; NPE – 80.1. The following energy/protein levels in the DM have been established: (AMEn – 14.17 MJ/kg; TMEn – 15.37 MJ/kg; CTDP - 84.15. The established nutritional values are similar to those of wheat, both fodders can be replaced each other in the production of compound feed for poultry.

Endogenous fat losses and true and apparent fat digestibility in adult and growing dogs fed diets containing poultry offal fat.

The objective of this study was to evaluate the coefficient of total tract apparent digestibility (CTTAD) of dietary nutrients, endogenous fat loss (EFL), dietary metabolizable energy (ME) content, coefficient of true digestibility (CTD) of fat and faecal parameters of dogs. A total of 16 puppies and 8 adult dogs were distributed according to a double Latin square experimental design. A basal diet was formulated, to which increasing levels (60, 120 and 180g/kg) of poultry offal fat oil were added. EFL was estimated using hyperbolic and linear regression as a function of LW/day and dry matter (DM) intake, respectively, and the CTD of fat was calculated. The CTTAD of acid-hydrolysis ether extract (AHEE) and ME content increased as dietary poultry offal fat level increased both in adult dogs and in puppies (p<.05). The CTTAD of DM and crude protein were higher in adult dogs than in puppies. EFL was estimated by hyperbolic regression as y=98.1094-13.6202/x and y=99.1280-26.1366/x, where y=CTTAD of AHEE (%) and x=AHEE intake/kgBW, for adult dogs and puppies, respectively, which yielded EFL values of 138 and 262mgAHEE per kgBW per day for adult dogs and puppies respectively. The EFL estimated by linear regression was 7.89g and 8.97g/kgDM intake for adult dogs and puppies respectively. The CTD estimated by both methodologies was higher in puppies than in adults (p<.05). Lower faecal DM and score, and higher ammonia production were obtained in puppies than adult dogs (p<.05). The results indicate good fat utilization and that fat digestibility is underestimated, as the CTTAD of AHEE does not take into account EFL, particularly at low-fat inclusion levels and in growing dogs, which have greater EFL than adult dogs.

Digestibility of calcium and digestible calcium from inorganic sources evaluated in swine by two methods

SUMMARY The objective of the study was to determine the digestible calcium from different sources by direct and indirect methods. Thirty castrated male pigs were used, distributed in randomized blocks, in six treatments: 1- Calcitic limestone; 2-Dicalcium phosphate powder 18%; 3- Dicalcium phosphate powder 20%; 4- Dicalcium microgranulated phosphate 18%; 5- Monodicalcium microgranulated phosphate 20%; 6- Monodicalcium microgranulated phosphate 21%, with six replicates and one animal per experimental unit. A basal diet was formulated to meet the nutritional requirements of the animals, except for calcium (0.06%) and the evaluated sources replaced the basal diet in order to provide 0.45% of total Ca. At the same time, two stool collection methods were evaluated: total collection and fecal indicator. The animals were housed in metabolism cages for 12 days to collect feces and urine to determine the calcium values used to estimate digestibility coefficients and digestible calcium. The total collection method and the faecal indicator method did not affect the true digestibility coefficient of calcium. The calcium digestibility of the microgranulated dicalcium phosphate 21% (MM21) was superior in comparison with the other calcium sources evaluated by the indirect method in the present study. The average values of true digestibility of the calcium sources, in percentage, were: calcitic limestone: 82.47; dicalcium phosphate powder 18%: 80.87; dicalcium phosphate powder 20%: 85.65; dicalcium microgranulated phosphate 18%: 81.65; monodicalcium microgranulated phosphate 20%: 84.15; and monodicalcium microgranulated phosphate 21%: 88.35. The two methodologies can be used to determine the digestibility of calcium.

Supplementation of pig diets in the growth and termination phases with different calcium sources.

The aim of this study was to evaluate the effect of supplementation of pig diets in the growth and termination phases with different calcium sources. In experiment I, 36 whole males were distributed in randomized blocks in six groups, with six replications. A basal diet was formulated to meet the animals' nutritional requirements except for calcium (0.09%), and the sources evaluated (calcitic limestone, monodicalcium phosphate, calcinated bone flour, and oyster flour) replaced the basal diet to provide 0.59% of total calcium. To determine the endogenous calcium, a diet containing low calcium (0.019%) was given simultaneously to another group of animals. Feces and urine were collected for determination the coefficients of apparent and true digestibility. In experiment II, 160 piglets were distributed in randomized blocks in four treatments, with five replications and four animals per experimental unit. Carcass and performance parameters, calcium concentration in bone and serum, and bone parameters were evaluated. The data were submitted to analysis of variance and factorial. The calcium source did not influence the digestibility coefficients determined by total collection (P>0.05). The digestibility of Ca from oyster flour estimated by collection with an indicator was higher than that from the other sources (P<0.05). Calcium sources did not interfere in the evaluated parameters (P>0.05). The sources studied in this work can be used to supplement growing pigs' diets.

Effect of partitioning the nonfiber carbohydrate fraction and neutral detergent fiber method on digestibility of carbohydrates by dairy cows.

Many nutrition models rely on summative equations to estimate feed and diet energy concentrations. These models partition feed into nutrient fractions and multiply the fractions by their estimated true digestibility, and the digestible mass provided by each fraction is then summed and converted to an energy value. Nonfiber carbohydrate (NFC) is used in many models. Although it behaves as a nutritionally uniform fraction, it is a heterogeneous mixture of components. To reduce the heterogeneity, we partitioned NFC into starch and residual organic matter (ROM), which is calculated as 100 - CP - LCFA - ash - starch - NDF, where crude protein (CP), long-chain fatty acids (LCFA), ash, starch, and neutral detergent fiber (NDF) are a percentage of DM. However, the true digestibility of ROM is unknown, and because NDF is contaminated with both ash and CP, those components are subtracted twice. The effect of ash and CP contamination of NDF on in vivo digestibility of NDF and ROM was evaluated using data from 2 total-collection digestibility experiments using lactating dairy cows. Digestibility of NDF was greater when it was corrected for ash and CP than without correction. Conversely, ROM apparent digestibility decreased when NDF was corrected for contamination. Although correcting for contamination statistically increased NDF digestibility, the effect was small; the average increase was 3.4%. The decrease in ROM digestibility was 7.4%. True digestibility of ROM is needed to incorporate ROM into summative equations. Data from multiple digestibility experiments (38 diets) using dairy cows were collated, and ROM concentrations were regressed on concentration of digestible ROM (ROM was calculated without adjusting for ash and CP contamination). The estimated true digestibility coefficient of ROM was 0.96 (SE = 0.021), and metabolic fecal ROM was 3.43 g/100 g of dry matter intake (SE = 0.30). Using a smaller data set (7 diets), estimated true digestibility of ROM when calculated using NDF corrected for ash and CP contamination was 0.87 (SE = 0.025), and metabolic fecal ROM was 3.76 g/100 g (SE = 0.60). Regardless of NDF method, ROM exhibited nutritional uniformity. The ROM fraction also had lower errors associated with the estimated true digestibility and its metabolic fecal fraction than did NFC. Therefore, ROM may result in more accurate estimates of available energy if integrated into models.

Metabolizable energy and digestible amino acids of full-fat soybean without or with protease supplementation in diets for broilers

ABSTRACT Two experiments were carried out to determine the energy values and the true ileal digestibility of amino acids of nine toasted full-fat soybeans (FFSB), without or with the addition of monocomponent protease. In the first experiment, to determine the energy values, the method of excreta collection was used with 1120 broiler chicks at 14 days old, distributed in randomized blocks in a 10x2 factorial arrangement with nine full-fat soybeans (30% included) plus a control diet (70%) without or with the addition of protease, totaling 20 treatments with 8 replicates and 7 birds per cage. In the second experiment, 1120 broiler chickens from 24 to 28 days of age were distributed in randomized blocks in a 10x2 factor arrangement, with nine full-fat soybeans (40% included) + a protein free diet (60%), without or with the addition of protease, totaling 20 treatments with 8 replicates and 7 birds per cage. Ileal digesta collection was used to determine the true digestibility coefficients and the digestible amino acid content of full-fat soybean. The average values of nitrogen-corrected apparent metabolizable energy (AMEn) and their respective metabolization coefficients (CAMEn) were 3207 kcal/kg and 62.57%, respectively. The average values of digestibility coefficients of crude protein and essential and nonessential amino acids were 86.79, 87.90 and 84.34%, respectively. The inclusion of protease improved (P&lt;0.05) all evaluated parameters. Therefore, its use is recommended in diets containing full-fat soybeans for broiler chickens.

Effect of limestone particle size and calcium to non-phytate phosphorus ratio on true ileal calcium digestibility of limestone for broiler chickens

The purpose of this study was to determine the effect of limestone particle size and calcium (Ca) to non-phytate phosphorus (P) ratio on the true ileal Ca digestibility of limestone for broiler chickens. A limestone sample was passed through a set of sieves and separated into fine (<0.5 mm) and coarse (1–2 mm) particles. The analysed Ca concentration of both particle sizes was similar (420 g/kg).Six experimental diets were developed using each particle size with Ca:non-phytate P ratios of 1.5:1, 2.0:1 and 2.5:1, with ratios being adjusted by manipulating the dietary Ca concentrations. A Ca-free diet was also developed to determine the basal ileal endogenous Ca losses. Titanium dioxide (3 g/kg) was incorporated in all diets as an indigestible marker.Each experimental diet was randomly allotted to 6 replicate cages (8 birds per cage) and fed from d 21 to 24 post hatch. Apparent ileal digestibility of Ca was calculated using the indicator method and corrected for basal endogenous losses to determine the true Ca digestibility.The basal ileal endogenous Ca losses were determined to be 127 mg/kg of dry matter intake.Increasing Ca:non-phytate P ratios reduced the true Ca digestibility of limestone. The true Ca digestibility coefficients of limestone with Ca:non-phytate P ratios of 1.5, 2.0 and 2.5 were 0.65, 0.57 and 0.49, respectively.Particle size of limestone had a marked effect on the Ca digestibility, with the digestibility being higher in coarse particles (0.71 vs. 0.43).

Determinação dos valores energéticos e aminoacídicos da silagem de grãos úmidos de milho para frangos de corte

Para a determinação dos valores energéticos da silagem de grãos úmidos de milho (SGUM), foram utilizados 120 frangos de corte machos, linhagem Cobb Slow, de 21 a 31 dias de idade, com peso médio inicial de 765,0±1,7 g, distribuídos em um delineamento inteiramente casualizado, com cinco tratamentos (ração referência-RR e níveis de substituição da SGUM de 10, 20, 30 e 40 %), seis repetições e quatro aves por unidade experimental. O período experimental teve duração de dez dias, sendo cinco de adaptação e cinco de coleta. O método de análise foi o de coleta total de excretas, para posterior análises de energia metabolizável aparente (EMA) e EMA corrigida pelo balanço de nitrogênio (EMAn) da SGUM. Para a determinação dos valores de aminoácidos, foi usada a técnica de alimentação forçada em 12 galos Leghorn cecectomizados, com peso médio de 1912,10±133,73 g. Seis animais receberam a SGUM e os outros seis permaneceram em jejum. Ao final do período de coleta de excretas, foi determinado o perfil de aminoácidos essenciais, coeficientes de digestibilidade verdadeira e o conteúdo digestível verdadeiro dos aminoácidos no alimento. A SGUM apresentou valores médios de EMA e EMAn de 2283 de 2272 kcal/kg, respectivamente, sendo que os valores energéticos foram negativamente influenciados pelos níveis de inclusão da SGUM. A cistina apresentou o menor coeficiente de digestibilidade, enquanto a leucina e a glutamina apresentaram os maiores valores de aminoácidos digestíveis.

Coeficiente de digestibilidade e valores de aminoácidos digestíveis verdadeiros de diferentes cultivares de milho para aves

The digestibility and true digestible amino acid content of eight cultivars of maize was determined using the method of force-feeding roosters cecectomized. The experimental design was completely randomized, represented by eight cultivars, five replicates and a rooster each. Five roosters were kept fasting for corrections corresponding to metabolic and endogenous losses of amino acids. Significant differences (P <0.05) among maize cultivars for the true digestibility of amino acids, methionine, threonine, arginine, cystine and serine were observed. The values of true digestibility coefficients for essential amino acids, for methionine, threonine and arginine ranged from 85.61 to 93.57%, from 66.27 to 84.97% and 83.39 to 93.10% respectively. For the other essential amino acids, the average values were: 72.84% for lysine, 85.64% for methionine+cystine, 87.29% for histidine, 85.33% for valine, 87.11% for isoleucine, 94.04% for leucine and 90.65% for phenylalanine. The true digestibility coefficients of nonessential amino acids cystine and serine that showed significant difference ranged from 73.97 to 89.21% and from 77.31 to 92.68%, respectively. For other non-essential amino acids, average values were 88.28% for alanine, 82.68% for aspartic acid, 92.19% for glutamic acid and 87.84% for tyrosine. Due to the variations observed, it is recommended periodic analyzes of maize cultivars used to formulate diets, to ensure the feed quality and the performance of the animals.

Digestibilidade do cálcio de ingredientes para suínos, avaliada por meio de dois métodos

Determinaram-se os coeficientes de digestibilidade aparente e verdadeira do cálcio (Ca) de ingredientes para suínos por meio de dois métodos. Foram utilizados 60 suínos machos castrados, alojados em gaiolas de metabolismo e distribuídos em delineamento experimental inteiramente ao acaso, em arranjo fatorial 2 x 10 (métodos x tratamentos) e seis repetições por tratamento. Os tratamentos consistiram em oito alimentos, uma ração basal (0,072% de Ca total) e uma ração com baixo teor de Ca (0,018%). Os coeficientes de digestibilidade aparente e verdadeira do Ca foram avaliados utilizando-se simultaneamente dois métodos: coleta total de fezes e coleta de fezes com indicador fecal (cinza ácida insolúvel - CAI). Os coeficientes de digestibilidade verdadeira do Ca, obtidos pelo método de coleta total e pelo método de indicador fecal, foram, respectivamente: calcário calcítico 1, 84,80 e 87,33%; calcário calcítico 2, 84,19 e 86,32%; fosfato bicálcico, 79,36 e 84,55%; fosfato monobicálcico, 83,83 e 85,81%; calcário dolomítico, 85,65 e 87,39%; farinha de carne e ossos (40% PB), 70,00 e 68,64%; farinha de carne e ossos (50% PB), 66,92 e 68,03%; farinha de vísceras, 73,40 e 73,95%, lactato de Ca, 95,10 e 97,33%. Não houve diferença significativa (P&gt;0,05) entre os métodos avaliados coleta total (80,14%) e indicador fecal (82,15%).

Digestibility and bioavailability of phosphorus from spray-dried yeasts in the diet of starting pigs (15-30 kg)

Two experiments were carried out to determine the bioavailability of phosphorus in two spray-dried yeasts - sugarcane yeast (SCY), and sugarcane yeast + brewer's yeast (SCBY) - in starting pigs, by comparing different methods (Apparent Digestibility Coefficient of Phosphorus - ADCP; True Digestibility Coefficient of Phosphorus - TDCP; slope ratio; and standard curve). In experiment I, a digestibility assay were carried out using 30 cross breed pig with initial weigh of 22.69 ± 4.24kg, allotted in a completely randomized design. The mean ADCP and TDCP values were 62.68 and 64.15% for SCY and 77.01 and 79.33% for SCBY. ADCP and TDCP for SCBY were higher (P&lt;0.05) than the values for SCY. In Experiment II, a growth test was conducted, 56 crossbred piglets, were utilized, with initial live weight of 15.11 ± 3.43kg, allotted in a completely randomized design, with seven treatments, four replications, and two pigs per experimental unit. The treatments consisted of a basal diet without supplementation with P and the same diet including supplementation with two levels of P (0.053% and 0.105%) from dicalcium phosphate, SCY and SCBY. The relative bioavailability mean value of 57.23% for SCY and 91.96% for SCBY, corresponding to 0.30% and 0.40% of available phosphorus, respectively.

The TMEn, Proximate Analysis, Amino Acid Content and Amino Acid Digestibility of Glandless and Commercial Cottonseed Meal for Broilers

Cotton seed meal (CSM) is an alternative ingredient in poultry diets but its use is limited due to the presence of gossypol and the potential effects of gossypol on digestibility of nutrients. Glandless cottonseed is available and contains very low gossypol but there has been a limited amount of poultry nutritional studies completed with glandless cottonseed meal (GCSM). The TMEn, proximate analysis, amino acid content and amino acid (AA) digestibility of a glandless (GCSM) and a commercial (CCSM) cottonseed meal were determined with broilers. Thirty 42-day old Cobb 500 male broilers were precision-fed 30g of CCSM, GCSM and glucose and excreta collected during a 48 h period. Glucose was fed to serve as a control (no nitrogen or AA content). The chemical composition, gossypol content, True metabolizable energy (TMEn) and digestibility coefficients for AA were calculated for both meals. The crude protein and fat content of GCSM was higher than the CCSM (54 and 51%, 6 and 2%, respectively). Both meals were similar in calcium, total phosphorus and phytic acid contents. The CCSM had a higher content of total and free gossypol (1.52 and 0.161%, respectively) when compared to GCSM (0.02 and .003%, respectively). The TMEn for the GCSM provided approximately one thousand kcal more per energy/ kg than the CCSM. The essential AA content (g/kg; 90% DM) was determined for both cottonseed meals and was generally higher for GCSM compared to CCSM but both types of CSM contained higher levels of key essential AA than reported values for AA in the literature. The most extreme differences were for methionine and cystine; % methionine content was approximately 2 fold higher than values in the literature and the % cystine was 74 to 93% higher. The true digestibility coefficients for essential AA ranged from the low of 73.9% for isoleucine to 91.8% for arginine, for CCSM; the amino acid digestibility coefficients for GCSM were all higher than 90% for the essential AAs.

Determination of true digestible amino acids of feedstuffs utilizing cecectomized roosters

The objective of this study was to estimate the true digestibility coefficients of amino acids and digestible amino acid values of some poultry feedstuffs. The feedstuffs were: babassu meal, sunflower meal, corn gluten meal, babassu starchy meal, meat and bone meal, common beans, pearl millet and residues of cookies, pasta and bread. The precise feeding method of Sibbald was used with adult cecectomized Leghorn roosters distributed in a completely randomized design, consisting of ten treatments and six replications with a rooster in each. The treatments were represented by the feedstuffs evaluated. The roosters were kept in a period of fasting for 36 hours and then fed 30 grams of feed. Samples were collected during 56 hours. Simultaneously, six roosters were kept fasting to make corrections to the metabolic and endogenous losses of amino acids. At the end of collections, the excreta obtained were weighed, freeze-dried and subsequently processed, so laboratory analyses were carried out and the coefficients of true digestibility of amino acids were determined. The mean values of the coefficients of true digestibility of essential and non-essential amino acids in percentage were respectively: 0.702 and 0.652 for the babassu meal; 0.852 and 0.786 for the sunflower meal; 0.928 and 0.887 for the corn gluten meal; 0.797 and 0.720 for the meat and bone meal; 0.364 and 0.339 for ground raw beans; 0.924 and 0.837 for ground pearl millet; 0.839 and 0.810 for cookie residue; 0.929 and 0.914 for pasta residue; and 0.904 and 0.899 for bread residue.

Apparent and true digestibility of protein and amino acid in feedstuffs used in Nile Tilapia feed as determined by the technique of dissection

The objective of this study was to determine the coefficients of apparent and true digestibility of protein and amino acids of five feedstuffs (corn, wheat bran, soybean meal, corn gluten meal and fish meal) in 900 sex-reversed Nile tilapia (Oreochromis niloticus) of the Thai strain during the growth phase, with an initial weight of 315±8.45 g. A total of 750 fish were distributed according to a randomized block design (repetitions in time) into five treatments with six replicates of 25 fish each. The remaining 150 fish were fed a protein-free diet to measure endogenous protein and amino acid losses in order to determine the true digestibility of these components. Each tested diet contained a single protein source, which consisted of one of the evaluated feedstuffs. Digestibility was indirectly estimated using chromic oxide at 0.50% as marker. Digesta was collected from the last 5 cm of the distal intestine (between the ileal-rectal valve and the anus) using the dissection technique. Apparent digestibility coefficients of protein and amino acids were, on average, 74.69 and 73.62% for corn, 73.74 and 72.81% for wheat bran, 86.01 and 84.66% for soybean meal, 85.19 and 84.29% for corn gluten meal, 76.74 and 75.56% for fish meal, respectively. True digestibility coefficients of protein and amino acids were, on average, 85.21 and 83.97% for corn, 84.41 and 83.74% for wheat bran, 87.22 and 87.51% for soybean meal, 87.97 and 87.34% for corn gluten meal, and finally 79.58 and 78.44% for fish meal, respectively.

Utilization of poultry by-product meal in diets for broiler chickens

This study evaluated diets containing poultry by-product meal (PBM) formulated on an equivalent digestible amino acid (AA) basis compared to a corn-soybean meal (SBM) diet. Three PBM (A, B, and C) produced in commercial rendering plants were evaluated. Mean true digestibility coefficients (percentages) for 15 AA in PBM A, B, and C were 81.75, 67.80 and 66.31, respectively. In a chick trial, 1-wk-old male chicks were fed from 8 to 21 and 21 to 42 days of age, a corn-SBM diet or diets containing 5 or 10% PBM formulated to be equal in digestible AA to the corn-SBM diet. From 8 to 21 d post hatch, feed efficiency of chicks fed 5 or 10% PBM A or 5% PBM C was equivalent to that of chicks fed the corn-SBM diet; however, dietary inclusion of 5 or 10% PBM B or 10% PBM C depressed feed efficiency even on a digestible AA basis. Chicks fed from 21 to 42 days of age, a diet containing 10% PBM B, had significantly lower weight gain and feed efficiency than chicks consuming the corn-SBM diet; however, diets containing 5 or 10% PBM A and C or 5% PBM B yielded weight gain and feed efficiency that was similar to the corn-SBM diet. The results of this study indicated that up 10% inclusion of two of the three PBM in chick diets had no detrimental effects on performance if the diets were formulated to contain adequate levels of digestible AA. Key words: Broiler chicks, digestible amino acid, poultry by-product.

Composição química e aminoacídica e coeficientes de digestibilidade verdadeira dos aminoácidos de farinhas de penas e sangue determinados em galos cecectomizados

Foram determinados a composição química e aminoacídica e os coeficientes de digestibilidade verdadeira dos aminoácidos (CDVaa) de farinhas de penas e sangue para aves obtidas de diferentes fornecedores. Utilizaram-se 30 galos cecectomizados distribuídos em delineamento experimental inteiramente casualizado, com quatro farinhas de penas e sangue (farinhas 1, 2, 3 e 4) e um tratamento no qual as aves permaneceram em jejum, seis repetições sendo a unidade experimental composta por um galo. As variações na composição química das farinhas de penas e sangue podem estar relacionadas à falta de padronização no processamento a que são submetidas. Os coeficientes médios de digestibilidade verdadeira dos aminoácidos essenciais e não-essenciais para as farinhas de penas 1, 2, 3 e 4 são, respectivamente, 75,14 e 68,41; 73,34 e 67,17; 78,99 e 75,41; 78,55 e 73,40%.

True and apparent digestibility of protein and amino acids of feed in Nile tilapia

It was determined in this work the coefficients of apparent and true digestibility of protein and amino acids of five feeds (corn, wheat bran, soybean meal, corn gluten meal, fish meal) in Nile tilapia. It was used 252 reverted Thai strain Nile tilapia (Oreochromis niloticus) in growth phase, with weight of 310 ± 9.68 g, distributed in experimental randomized blocks design, with five treatments, six replicates per treatment and seven fish per experimental unit. Each experimental diet contained a single source of protein, composed by the studied ingredients. An additional group of fish was fed protein-free diet for quantification of the endogenous fraction and determination of true digestibility coefficients. Digestibility was estimated by the indirect method by using chromium oxide at the concentration of 0.50% of the diet as a marker, performing fecal collection at every four hour interval by using decantation technique. Coefficients of apparent digestibility of the protein and amino acids are: corn, 83.57 and 82.45%; wheat bran 82.87 and 81.47%; soybean meal 91.12 and 89.41%; corn gluten meal 90.07 and 87.78%; fish meal 83.53 and 81.65% respectively. Coefficients of true digestibility of protein and the mean of the amino acids are: corn, 90.02 and 89.60%; wheat bran 89.62 and 89.14%; soybean meal 93.58 and 91.88%; corn gluten meal 92.50 and 90.34%; fish meal 86.01 and 84.27%, respectively.