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A study was conducted to evaluate the effects of a supplemental α-amylase on energy and nutrient utilization of broiler chickens fed diets with variable amounts of corn. A total of 480 slow feathering Cobb × Cobb 500 male broilers were randomly distributed into 10 treatments with 8 replicates of 6 birds each. Birds were fed a common starter to 14 D post-hatch. The experimental diets were provided subsequently until 25 D, which were a conventional corn-soy basal diet (CS) and a corn-soy diet displaced with 40% of corn (CN). These were fed as-is or supplemented with 40, 80, 120, or 160 kilo-Novo α-amylase units (KNU)/kg. Dietary treatments were distributed factorially as a 2 × 5 arrangement (diet type vs. amylase). Samples of feed, excreta, and ileal digesta were analyzed for determination of ileal digestible energy (IDE), ME, total tract retention, and digestibility of dry matter, protein, and fat. No interactions between diet type and amylase were observed. The CN diet had lower (P < 0.05) energy utilization and nutrient digestibility when compared to the CS diet. AMEn and IDE increased (P < 0.05) by 110 and 207 kcal/kg, respectively, when CS and CN diets were supplemented with 80 KNU/kg. The amylase added to the CS diet led to quadratic increases (P < 0.05) on growth performance, IDE, AME, and AMEn, as well as in dry matter, protein, and fat digestibility. Energy utilization and crude protein digestibility were linearly increased (P < 0.05) when amylase was added to the CN diet or the extrapolated 100% of corn. In conclusion, energy utilization, digestibility of crude protein, fat, and dry matter increased with amylase supplementation in corn-soy-based diets. When amylase was tested in a complete diet having 53.6% corn, 100 and 105 KNU/kg maximized AMEn and IDE, respectively; however, the maximum energy response in the CN diet or 100% of corn was not achieved until 160 KNU/kg, suggesting an association between amylase dose optimization and dietary starch concentration. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effects of dietary α-amylase and β-xylanase, in single or combined supplementation, on growth performance of broiler chickens fed maize-soy diets. A total of 1800 slow feathering, Cobb × Cobb 500 male broilers were randomly distributed to 8 treatments with 9 replicates of 25 birds each. Broilers were fed starter and finisher diets respectively from 1 to 21 and 22 to 40 d Broilers were fed starter and finisher diets respectively from 1 to 21 and 22 to 40 d. A negative control (NC) diet was formulated to contain 12.35 MJ/kg and 12.85 MJ/kg in the starter and finisher phases, respectively. A further four control diets were formulated with orthogonal energy density increases in increments of 0.21 MJ/kg to a maximum of 13.17 MJ/kg (starter) and 13.67 MJ/kg (finisher). All control diets were formulated to be equivalent in amino acids and minerals. The NC diet was supplemented with α-amylase (80 kilo-Novo α-amylase units/kg), β-xylanase (100 fungal β-xylanase units/kg), or both enzymes combined at the same supplementation levels. Increasing AME n resulted in a linear increase (P < 0.01) in BWG and a linear decrease (P < 0.01) in FCR from 1 to 40 d. Corresponding AME n estimates for BWG and FCR from 1 to 40 d were, respectively 0.41, 0.35, and 0.57 and 0.18, 0.11, and 0.21 MJ/kg for amylase, β-xylanase and amylase + β-xylanase. In conclusion, supplementing maize-soy diets with α-amylase and β-xylanase led to increased estimated energy yields. A marked difference occurred in favor of α-amylase when compared to β-xylanase supplementation whereas adding both enzymes in the same feed generated similar AME n to the single addition of α-amylase. Growth performance responses corresponded to findings in the AME n assay. [ABSTRACT FROM AUTHOR]

A data set of individual observations was compiled from digestibility trials to examine the relationship between the duodenal purine bases (PB) flow and urinary purine derivatives (PD) excretion and the validity of different equations for estimating rumen microbial N (Nm) supply based on urinary PD in comparison with estimates based on duodenal PB. Trials (8 trials, n = 185) were conducted with male sheep fitted with a duodenal T-type cannula, housed in metabolic cages, and fed forage alone or with supplements. The amount of PD excreted in urine was linearly related to the amount of PB flowing to the duodenum (P < 0.05). The intercept of the linear regression was 0.180 mmol/(d·kg0.75), representing the endogenous excretion of PD, and the slope was lower than 1 (P < 0.05), indicating that only 0.43% of the PB in the duodenum was excreted as PD in urine. The Nm supply estimated by either approach was linearly related (P < 0.05) to the digestible OM intake. However, the Nm supply estimated through either of 3 published PD-based equations probably underestimated the Nm supply in sheep. [ABSTRACT FROM AUTHOR]

Responses of broilers to dietary amino acids (AA) have been extensively studied especially after their synthetic and crystalline forms became available. Synthetic (DL-Met and Met analogue) as well as crystalline ( l -Lys and l -Thr) AA are now widely used in commercial production diets to reduce crude protein (CP) levels to allow competitive bird performance. In parallel, birds diets formulated without excess CP have reduced nitrogen excretion as well as lower costs. Diet composition affects the order of limiting AA after Thr and this has led to some debate on the feasibility of including the next limiting AA, which would be the fourth, in most of the scenarios. Using maize-soy type diets, the literature suggests that Val is the fourth AA limiting. As the commercial cost of l -Val is progressively reduced, concerns have been raised on the effectiveness of its supplementation to produce broiler responses that are similar compared with feed that does not contain this AA. Antagonisms between branched-chain amino acids (BCAA) have been reported in the past; however, their use in the current maize-soy diet commercial setting is unlikely. Formulation of diets with crystalline l -Val can potentially modify the ratio between BCAA as it is supplemented in diets that are further reduced in CP. Increased availability of AA can also be achieved when diets are supplemented with exogenous proteases; however, the resulting impact in the total profile of AA is different because a wider group of AA becomes simultaneously available when compared to diets receiving addition of synthetic/crystalline AA one by one. A scenario of CP reduction in diets seems clear with the increasing use of supplemental AA along with protease in broiler diets. The knowledge of CP reduction strategies, such as protease and synthetic AA supplementation, can be a valuable asset due to the competitive nature of broiler meat production business. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effects of an exogenous protease added to diets having soybean meal (SBM) from two geographic areas in Brazil (South or North). Evaluation was conducted on energy utilisation and nutrient digestibility using 224 slow feathering Cobb × Cobb 500 male broilers. Birds were fed a common starter diet to d 15. Semi-purified experimental diets containing 555 g/kg SBM and 408 g/kg maize starch plus minerals and vitamins were provided afterwards until 24 d. Diets had 0.1 g/kg phytase and 10 g/kg Celite (indigestible marker). Birds were randomly distributed in a 2 × 2 factorial arrangement of the two SBM with or without protease supplementations (0 or 15,000 protease units/kg) from 17 to 24 d. Excreta were collected from 21 to 23 d and ileal content was collected from all birds. Samples of feed, excreta, and ileal content were analysed for determination of total tract retention and ileal apparent digestibility. No interactions between SBM and protease were observed. Broilers fed semi-purified diets formulated with South SBM had lower (P < 0.05) ileal digestibility of crude protein and also from most amino acids (AA) when compared with birds fed North SBM. Ileal digestible energy was increased (P < 0.01) by 0.51 MJ/kg when birds were fed the diet supplemented with protease. Indispensable and dispensable AA digestibility also increased (P < 0.05) with protease supplementation. Ileal digestibility coefficients of Met, Lys, Thr and Val were increased (P < 0.05) by 3.1%, 3.1%, 4.8%, and 3.3%, respectively when birds were fed the diet supplemented with protease. Results from this experiment show that utilisation of energy and AA from SBM depends on its origin, but protease supplementation improved their utilisation regardless of the SBM source. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effects of increased levels of a β-xylanase on energy and nutrient utilization of broiler chickens fed corn-soy diets. A total of 480 slow feathering Cobb × Cobb 500 male broilers were randomly distributed to 10 treatments having 8 replicates of 6 birds each. Birds were fed a common starter diet to d 14 post hatch (3,050 kcal/kg AMEn, 21.7% CP, 1.05% Ca, and 0.53% nPP). The experimental diets were provided afterwards until 25 d. Two experimental diets, a conventional corn/soy-based basal diet (CS) and the basal diet in which 40% of the diet was displaced by corn (CN), were fed as-is or supplemented with 50, 100, 150, or 200 fungal β-xylanase units (FXU)/kg. Dietary treatments were distributed factorially as a 2 × 5 arrangement. Samples of feed, excreta, and ileal digesta were analyzed for determination of ileal digestible energy (IDE), metabolizable energy, and total tract retention of protein and lipid. No interactions between diet and xylanase were observed. The CS diets had higher (P < 0.05) energy utilization and nutrient digestibility when compared to the CN diets. AMEn and IDE were improved (P < 0.05) by 192 and 145 kcal/kg, respectively, when diets were supplemented with 100 FXU/kg xylanase. The xylanase added to the CN diet led to quadratic increases (P < 0.05) in IDE (Y = − 0.014x2 + 2.570x + 3,155; r2 = 0.60) and in AMEn (Y = − 0.016x2 + 3.982x + 3,155; r2 = 0.68). Crude protein digestibility and AMEn were linearly increased (P < 0.05) when xylanase was added to the CN diet. In conclusion, energy utilization and digestibility of crude protein and dry matter increased with xylanase supplementation in corn/soy-based diets. When xylanase was tested in the CS diet, 92 and 124 FXU/kg maximized the energy release effect; however, the maximum energy response in the CN diet or corn was not achieved until 200 FXU/kg. [ABSTRACT FROM AUTHOR]

A study was conducted to determine the ileal digestible energy (IDE), ME, and MEn contents of bakery meal using the regression method and to evaluate whether the energy values are age-dependent in broiler chickens from zero to 21 d post hatching. Seven hundred and eighty male Ross 708 chicks were fed 3 experimental diets in which bakery meal was incorporated into a corn-soybean meal-based reference diet at zero, 100, or 200 g/kg by replacing the energy-yielding ingredients. A 3 x 3 factorial arrangement of 3 ages (1, 2, or 3 wk) and 3 dietary bakery meal levels were used. Birds were fed the same experimental diets in these 3 evaluated ages. Birds were grouped by weight into 10 replicates per treatment in a randomized complete block design. Apparent ileal digestibility and total tract retention of DM, N, and energy were calculated. Expression of mucin (MUC2), sodium-dependent phosphate transporter (NaPi-IIb), solute carrier family 7 (cationic amino acid transporter, Y+ system, SLC7A2), glucose (GLUT2), and sodium-glucose linked transporter (SGLT1) genes were measured at each age in the jejunum by real-time PCR. Addition of bakery meal to the reference diet resulted in a linear decrease in retention of DM, N, and energy, and a quadratic reduction (P < 0.05) in N retention and ME. There was a linear increase in DM, N, and energy as birds' ages increased from 1 to 3 wk. Dietary bakery meal did not affect jejunal gene expression. Expression of genes encoding MUC2, NaPi-IIb, and SLC7A2 linearly increased (P < 0.05) with age. Regression-derived MEn of bakery meal linearly increased (P < 0.05) as the age of birds increased, with values of 2,710, 2,820, and 2,923 kcal/kg DM for 1, 2, and 3 wk, respectively. Based on these results, utilization of energy and nitrogen in the basal diet decreased when bakery meal was included and increased with age of broiler chickens. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effects of dietary α-amylase and β-xylanase supplementation of corn-soy diets, formulated with or without supplemental phytase, on growth performance, energy utilization, and starch digestibility in broiler chickens. A total of 336 slow-feathering, Cobb × Cobb 500 male broilers were randomly distributed to 6 treatments having 8 replicates of 7 birds each. Birds were fed a common starter diet to d 14 post-hatch (3,050 kcal/kg AMEn, 21.7% CP, 1.05% Ca, and 0.53% nPP). The experimental diets were provided afterwards until d 25. A 2 × 3 factorial arrangement of 2 control diets (basal = corn-soy diet without added phytase or PHY = cornsoy diet formulated with 1,000 phytase units/kg) and 3 carbohydrase supplementations (0, 80 kilo-Novo α-amylase units/kg, or 80 kilo-Novo α-amylase units/kg + 100 fungal β-xylanase units/kg) was used from d 14 to 25. Excreta were collected from 21 to 24 d and all birds were euthanized at 25 d for jejunum and ileum content collection. Samples of feed, excreta, and jejunal and ileal digesta were analyzed for determination of total tract retention and ileal apparent digestibility. No interactions between diet and carbohydrase were observed. Broilers fed diets formulated with phytase or supplemented with amylase + xylanase had higher BW gain (BWG) and lower FCR (P < 0.05) when compared with birds fed diets without carbohydrases. Relative to the basal diet, AMEn was increased (P < 0.01) by 70 kcal/kg and 99 kcal/kg when birds were fed the diet supplemented with amylase and amylase + xylanase, respectively. Starch digestibility in the jejunum and ileum was increased (P < 0.05) by 3.5% and 2.4%, respectively, when birds were fed the diet supplemented with amylase + xylanase. Results from this experiment show that corn-soy diets having phytase and supplemented with amylase and xylanase led to increased growth performance, AMEn, and starch digestibility in broilers. Furthermore, the efficacy of exogenous amylase and xylanase was independent of the presence of microbial phytase. [ABSTRACT FROM AUTHOR]

Since it started as an organized economic activity, poultry production has been undergoing an evolution toward the optimization of its feed formulation features. Notably, advances in the knowledge of birds' nutrient requirements have allowed recommendations that are increasingly closer to the needs of the birds. Over time, availability of nutrients and energy has been incorporated into those recommendations, especially to compensate for the variability in the digestibility of nutrients originating from variable feed ingredient sources. Instead of using the total energy and nutrient content, current tables of nutrient recommendations provide an estimate of the digestible fractions of the nutrients in ingredients. For instance, nonphytate P is preferred instead of total P to account for the unavailable phytate P, and digestible amino acids to account for the differences in digestibility of amino acids in different ingredients, whereas energy is usually expressed as a proportion that has been digested and metabolized (AME). With the increasing interest in the use of exogenous enzymes in poultry feeds, special attention is directed to the feed substrates such that an added enzyme can match it, forming an enzyme-substrate complex that will be followed by a chemical reaction within the gastrointestinal tract. As a consequence of a degradation reaction, nutrients released can be absorbed and metabolized. In general, nutritional data banks used in linear feed formulation software have limited data on the proportions of fractions of ingredients that are indigestible. Therefore, estimations of the presence of many substrates in the feeds, and therefore the benefits of adding exogenous enzymes, are frequently limited because of the scarcity of adequate information. The objective of this review paper is to provide insights into the use of expanded nutrient databanks to include all the molecules considered potentially indigestible for poultry such that the inclusion of exogenous enzymes allows the estimation of the values of the product originated by their hydrolysis. [ABSTRACT FROM AUTHOR]

The amount of digesta flowing to the duodenum is a relevant measurement for the evaluation of nutrient supply to ruminants, which is usually estimated in animals fitted with a duodenal T-type cannula using internal or external markers. This study evaluated acid detergent fiber (ADF) compared with external (C32 n-alkane) and internal [sulfuric acid lignin (ADL) and n-alkanes C31 and C33] markers for estimating duodenal flow and(or) ruminal digestibility of dry matter (DM) in cattle and sheep. In the first assay, 4 duodenally cannulated Holstein steers housed in metabolism cages, dosed with C32 n-alkane, and fed Avena strigosa plus concentrate and increasing levels of tannin extract to reduce ruminal digestibility, were used in a Latin square design. The mobile-bag technique was used to measure the intestinal disappearance of ADL and ADF from forage (Avena strigosa, Pennisetum purpureum, Cynodon dactylon, and Medicago sativa) and concentrate (corn grain, soybean meal, and sunflower meal) samples that were previously incubated in the rumen of additional fistulated steer for 12, 24, 36, or 48 h. The ADF concentration in residues recovered in the feces was strongly related to the ADF concentration in residues at the duodenum (R² = 0.93, standard deviation = 30.0, n = 901). This relationship showed a lower precision for ADL fraction (R² = 0.88, standard deviation = 12.6, n = 590). In a second assay, duodenal flow and ruminal DM digestibility were calculated from the duodenal and fecal concentration of either marker. We observed a significant effect of marker type on ruminal DM digestibility values, and the effect of tannin treatments was observed only when ADF or ADL was used as the marker. The lowest residual error was obtained for ADF. Ruminal DM digestibility was, on average, higher for C31 and C33 n-alkanes, and the use of dosed C32 n-alkane resulted in a negative value. In the third assay, a data set of 235 individual observations was compiled from digestibility trials to compare ADF and ADL as markers for estimating duodenal digesta flow in weathers (n = 204) and cattle (n = 31). We observed a strong relationship between markers (R² = 0.84 in sheep and R² = 0.88 in cattle), but variance analysis within trials indicated that ADF was more precise than ADL. In conclusion, in digestibility trials in which fecal output was measured and spot samples of the duodenal digesta were obtained, duodenal flow and ruminal digestibility of the DM may be estimated from the relationship between the ADF concentration in feces and that in the duodenal digesta of ruminants. [ABSTRACT FROM AUTHOR]

Quillaja saponaria and Yucca schidigera are plants rich in saponins, which present surfactant or detergent properties with molecules containing fat-soluble nucleus and either a steroid or triterpenoid structure. Quillaja and yucca biomass also contain polyphenols, which possess antioxidant, antimicrobial, and anti-inflammatory properties. Plant-based feed additives have been increasingly used in poultry feeds; therefore, this study was conducted to evaluate the effects of an additive containing polyphenols and saponins of a proprietary blend from Q. saponaria and Y. schidigera (QY) biomass on growth performance and carcass yield as well as on nutrient digestibility, blood biochemistry and intestinal measurements of broilers. Broilers were fed a nonsupplemented control diet (Control); Control supplemented with a commercial additive from QY (250 g/ton) from d 1 to 42; Control + QY from d 28 to 42, and Control + QY from d 35 to 42. There were no effects of dietary treatments on BW gain, feed intake, carcass yield, and blood biochemistry parameters; however, from d 1 to 42, birds fed QY during the overall period had lower FCR compared to the Control. Intestinal permeability was reduced with QY, whereas higher ileal digestibility of DM, nitrogen and energy as well as higher villus height and lower crypt depth were obtained when broilers were fed QY from d 28 to 42. In conclusion, the quillaja and yucca biomass additive improved jejunal morphometric, intestinal permeability and nutrient digestibility of broilers, and these effects were associated with the improved FCR. The additive demonstrated satisfactory results on nutrient digestibility and villus height when supplemented in grower and finisher diets for broilers. [ABSTRACT FROM AUTHOR]

This study was carried out with the purpose of evaluating the effect of supplementing hens’ diets with trace minerals from inorganic or organic sources on the productive performance, eggshell quality, and eggshell ultrastructure of laying hens. Three hundred sixty Hy-Line W36 laying hens between 47 to 62 wk of age were used and distributed in a completely randomized experimental design with 9 treatments, 5 replicates, and 8 birds for each experimental unit. The treatments consisted of a control diet without supplementation of the trace minerals Mn, Zn, and Cu; 4 supplementation levels of these trace minerals from an inorganic source; and the same levels of supplementation from an organic source (proteinates). The supplementation levels in milligrams per kilogram for Mn, Zn, and Cu, were, respectively, 35-30-05, 65-60-10, 95-90-15, and 125-120-20. There was no effect of supplementation of trace minerals on the rate of posture, feed intake, feed conversion, specific weight, and Haugh unit of eggs. However, there was a quadratic effect (P < 0.05) of the levels of trace mineral supplementation on average egg weight and egg mass; the results did not differ regarding the source used. The increase in the levels of supplementation of Mn, Zn, and Cu provided a linear increase (P < 0.05) in the breaking strength and the percentage of eggshell. There was a linear decrease (P < 0.05) in the egg loss and the number of mammillary buttons in the shell. The best results were obtained using diets supplemented with trace minerals from an organic source because these diets provided lower egg loss, higher thickness, and increased strength of the shell. Structurally, organic Mn, Zn, and Cu provided higher thickness of the palisade layer and lower mammillary density. The trace mineral supplementation improved the structural characteristics and the quality of the eggshells. [ABSTRACT FROM AUTHOR]

1. Gradual feed restriction was applied to broilers in order to reduce growth rate and, as a consequence, gradually impacts wooden breast myopathy occurrence. Ultrasound (US) images of breast muscle in live birds were correlated with breast fillets presenting wooden breast characteristics (WB). 2. A total of 1800 Cobb × Cobb 500 slow-feathering male chicks were fed one of the six feed restriction treatments with 12 replicates of 25 birds each, in a completely randomised design. Birds were fed ad libitum or were pair-fed to 50%, 60%, 70%, 80% or 90% of normal ad libitum intakes from 8 to 49 d to provide a gradual reduction in growth rate. Ultrasound images were obtained weekly from all birds and, in parallel, one bird per pen was weekly slaughtered and the major breast muscle was weighed and WB graded as 0 (normal), 1 (mild hardening in the upper), 2 (moderate hardening in the upper and/or lower), 3 (severe hardening) and 4 (severe hardening with haemorrhagic lesions and yellow fluid). Blood was taken for analysis of enzymes related to muscle cell breakdown. 3. Feed restriction applied at 50%, 60%, 70%, 80% and 90% of the ad libitum feed intake (FI) resulted in decreased body weight gain (BWG; P ≤ 0.05). 4. From 21 to 49 d, the increasing feed restriction led to linear increases (P ≤ 0.05) in WB scores, fibre density as well as breast depth and breast echogenicity. Creatine kinase, lactate dehydrogenase and aspartate aminotransferase concentration decreased linearly when broilers were feed restricted (P ≤ 0.05). 5. Wooden breast was positively correlated with echogenicity at 21 d (r = 0.510), 28 (r = 0.531), 35 (r = 0.470), 42 (r = 0.430) and 49 d (r = 0.548) (P ≤ 0.001). The use of breast echogenicity can be an additional tool to early detect alterations related to wooden breast. [ABSTRACT FROM AUTHOR]

Ingested starch is a polymer of glucose that consists of α-1,4 and/or α-1,6 bonds. When α-1,4 bonds occur between glucose monomers, the resulting polymer is called amylose, whereas when α-1,6 bonds occur the resulting polymer is referred to as amylopectin. Amylopectin, on the other hand, has a more chaotic macro-structure as the α-1,6 branching points disrupt the helical structure creating amorphous regions often referred to as "waxy." The ratio between amylose and amylopectin in starch determines whether a starch may be categorized as "waxy" or "high amylose" and this varies between and within cereal grain types. Waxy corn may contain as much as 99% amylopectin, whereas high amylose corn starch may be more than 70% amylose. Furthermore, there is considerable heterogeneity in the size of the starch granules in seeds from various plants and in the nature of the crystalline micro- and macro-structure that favors, or not, digestion. Following initial hydrolysis by endogenous amylases, the process of starch digestion is completed by the brush-border enzymes maltase and iso-maltase, and the resulting glucose is absorbed via Na-dependent transport systems for eventual metabolism via the citric acid cycle. As most poultry diets contain 400–500 g/kg starch, successfully converting this ingested starch into glucose is critically important to energetic status and this may be particularly true in older animals with a much greater starch intake. Therefore, factors which delay, impede or interfere with the digestion of starch have a profound effect on the energy value of a given diet. Such factors include the nature of the starch crystals, the extent of starch "damage" during hydrothermal processing of feed or feed ingredients, factors that may inhibit the optimal functioning of endogenous amylases and issues around extraction of glucose from the lumen via Na-dependent transport systems. It was the purpose of this review to discuss such factors and to outline the usefulness of exogenous sources of amylase in monogastric nutrition with emphasis both on direct digestible energy effects. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effects of L-glutamic acid (Glu) on the productive performance, eggshell quality, bone characteristics, and morphologic parameters of laying hens. Two hundred and forty 53-wk-old Hy-Line W36 laying hens were randomly allocated into 5 treatments, 6 replicates, and 8 birds each. The experimental period was 16 wk. The treatments consisted of a Basal diet (Glu calculated at 2.68%) and 4 L-glutamic acid inclusion levels: 2.88, 3.08, 3.28, and 3.48%. Glu inclusion levels in the hens diet had an increasing linear effect (P < 0.05) on eggshell Ca concentration and bone (tibiotarsus) strength index, and a decreasing linear effect (P < 0.05) on the Seedor index. Serum biochemistry results for total and ionic Ca, inorganic P, and alkaline phosphatase were affected by blood collection time (04:00 Pm, 03:00 Am, and 12:00 Pm) but not by the treatments. Jejunum morphometric variables were not influenced by the treatments except for crypt depth, which demonstrated a quadratic effect (P < 0.05). However, proliferating cell nuclear antigen qualitative immunohistochemical analysis of the jejunum showed more positive nuclei in the villus with the addition of Glu. Both with the basal diet and the lowest Glu inclusion treatment, positive nuclei were observed in the crypts and at the base of the villus, while in the treatments with higher Glu levels, positive cells were common all along the villus mucosa, including its extremity. In conclusion, diets formulated with increased levels of Glu had beneficial effects on eggshell Ca concentration, tibiotarsus structure, and proliferative activity of the jejunum of 69-wk-old laying hens. Therefore, dietary L-glutamic acid can be considered an alternative additive to improve bone characteristics in the productive phase of laying hens. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effects of dietary iron (Fe) from inorganic and organic sources on breeder hen chicks originated from Pale and Dark eggs. A total of 640 40-wk-old Cobb 500 broiler breeder hens were randomly distributed into 32 floor pens (20 females and 2 males per pen) and fed ferrous sulfate (Fe-S) at 40 ppm Fe; Fe-amino acid complex (Fe-AA) at 40 ppm Fe, or Fe-S and Fe-AA (Fe-S + Fe-AA) at 90 ppm Fe, 50 ppm provided by Fe-S and 40 ppm by Fe-AA. Breeder performance was evaluated from 40 to 67 wk, and laid eggs were separated by color (Pale and Dark) to compose 6 treatments. A total of 600 hatching eggs from each treatment were collected at 65 wk and incubated. Hemoglobin and hematocrit were analyzed from 100 hatched chicks per treatment. In parallel, 1,200 1-day-old male chicks were randomly distributed in a 3 × 2 (Fe fed to hens and eggshell color) factorial arrangement (48 floor pens; 25 birds/pen) and fed common diets. Hens fed the Fe-AA diet produced more eggs per hen housed and had higher fertility compared to hens fed Fe-S whdereas those fed Fe-S + Fe-AA had intermediate results. Chick hemoglobin and hematocrit were not affected by dietary Fe and eggshell color. Breeder hens fed diets with Fe-AA and Dark eggs originated broilers that had improved growth performance and carcass and breast weights. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate growth performance, carcass and breast yields, and the occurrence and severity of white striping (WS) and wooden breast (WB) myopathies of broilers fed diets supplemented with increasing dietary levels of an organic source of selenium (Zn-L-SeMet). Broilers were fed 6 treatments with 12 replications of 26 birds in a 4-phase feeding program from 1 to 42 days. Corn-soy-based diets were supplemented with 0, 0.2, 0.4, 0.6, 0.8, and 1.0 ppm of Zn-L-SeMet. At 42 d, 6 birds were randomly selected from each pen (n = 72) and processed for carcass and breast yields. Breast fillets were scored for WS and WB at 42 days. Increasing Zn-L-SeMet led to quadratic responses (P  < 0.05) for FCR from 1 to 7 d, BWG from 22 to 35 d, and for both responses from 8 to 21 d and 36 to 42 d, as well as in the overall period of 42 days. Carcass and breast yields presented a quadratic improvement (P  < 0.01) with increasing Zn-L-SeMet supplementation and Se requirements were estimated at 0.85 and 0.86 ppm, respectively. In the overall period, estimates of Se requirements were 0.64 ppm for BWG and 0.67 ppm for FCR. White striping and WB scores presented quadratic increases (P  < 0.01), and maximum scores were observed at 0.68 and 0.67 ppm, respectively. Broilers fed diets formulated without Se supplementation had a higher percentage of normal fillets compared to other Se supplementation levels (quadratic, P  < 0.05). In conclusion, increasing Se supplementation to reach maximum growth performance led to higher degrees of severity of WS and WB. Selenium requirements determined in the present study were significantly higher than the present commercial recommendations. [ABSTRACT FROM AUTHOR]

As the first limiting amino acid in cornsoy broiler diets, methionine (Met) is supplemented using commercial synthetic sources as demanded to obtain economic feed formulations. The Met analogue DL-2-hydroxy-4-(methylthio)-butanoic acid (HMTBA) is largely utilized with that objective. This study intended to obtain responses of broilers fed with increasing levels of HMTBA, from 28 to 42 d, such that economic returns can be calculated. A total of 2,106 Cobb x Cobb 500 one-day-old male broilers was randomly placed in 81 floor pens (2.7 m² each). Birds were fed conventional starter (zero to 14 d) and grower (14 to 28 d) diets. Starting at 28 d of age, pens of 26 birds were randomly allocated into 9 feed treatments with 9 replications having increasing supplementations with HMTBA (0.00, 0.07, 0.14, 0.21, 0.28, 0.35, 0.42, 0.49 and 0.56%). These were prepared by mixing different proportions of corn-soy dilution and summit diets, which had the same formulated concentration of nutrients and energy [19.7% CP, 0.90% Ca, 0.45% Av. P, 0.95% digestible Lys, and 3,150 kcal/kg AMEn], with the exception of HMTBA [0.56% in the summit but not supplemented in the corn-soy dilution diet (0.52% digestible TSAA)]]. Growth performance was evaluated until 42 d when carcass yield and commercial cuts were evaluated using 6 birds randomly taken from each pen. Body weight gain (BWG), feed conversion ratio (FCR), proportion of breast fillets, and abdominal fat were adjusted using linear broken-line, exponential asymptotic and quadratic polynomial regression models (P < 0.05). Estimations of maximum responses for supplemented HMTBA by the linear broken-line model were 0.17% for BWG, 0.14% for FCR, and 0.29% for breast fillets. Using exponential and quadratic regressions, optimized HMTBA supplementations were obtained at 0.34 and 0.35% for BWG, 0.20 and 0.33% for FCR, and 0.31 and 0.36% for breast fillets, respectively. Supplemental levels of HMTBA that optimize growth performance and breast meat in male broilers from 28 to 42 d, using different regression models, varied from 0.14 to 0.36%. [ABSTRACT FROM AUTHOR]

A study was conducted to determine the AMEn contents of fat by-products from the soybean oil industry for broiler chickens. A total of 390 slow-feathering Cobb x Cobb 500 male broilers were randomly distributed into 13 treatments having 6 replicates of 5 birds each. Birds were fed a common starter diet from placement to 21 d. Experimental corn-soy diets were composed of four fat sources, added at 3 increasing levels each, and were fed from 21 to 28 d. Fat sources utilized were acidulated soybean soapstock (ASS), glycerol (GLY), lecithin (LEC), and a mixture (MIX) containing 85% ASS, 10% GLY and 5% LEC. A 4 x 3 + 1 factorial arrangement was used with 4 byproducts (ASS, GLY, LEC, or MIX), 3 inclusion levels and 1 basal diet. Each of the four fat by-product sources was included in the diets as follow: 2% of byproducts (98% basal + 2% by-product), 4% (96% basal + 4% by-product), or 6% (94% basal + 6% by-product). Birds were submitted to 94, 96, 98, and 100% of ad libitum feed intake; therefore, the differences in AMEn consumption were only due to the added by-product. Total excreta were collected twice daily for 72 h to determine apparent metabolizable energy contents starting at 25 d. The AMEn intake was regressed against feed intake and the slope was used to estimate AMEn values for each fat source. Linear regression equations (P < 0.05) estimated for each by-product were as follow: 7,153X - 451.9 for ASS; 3,916X - 68.2 for GLY; 7,051X - 448.3 for LEC, and 8,515X - 622.3 for MIX. Values of AMEn were 7,153, 3,916, 7,051, and 8,515 kcal/kg DM for ASS, GLY, LEC, and MIX, respectively. The present study generated AMEn for fat by-products data that can be used in poultry feed formulation. It also provides indications that, by adding the 3 by-products in the proportions present in the MIX, considerable economic advantage can be attained. [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effects of supplementing maize-soy diets with a commercial xylanase-β-glucanase complex [β-xylanase, 1,3(4)-β-glucanase, and 1,4-β-glucanase] on growth performance, energy and amino acid utilisation of broiler chickens. A total of 2016 Cobb × Cobb 500 1-d-old male chicks were distributed into 9 treatments with 8 replicates of 28 birds each in a completely randomised design. Treatments consisted of a Control diet formulated with AME and nutrients as commercially used by the Brazilian integrators without enzyme supplementation as well as 8 other diets having reductions in formulated AME (−0.33 and −0.50 MJ/kg) and digestible amino acids (dig. AA; −3 and −6%). These diets were supplemented or not with 50 mg/kg of the enzyme complex. Ileal contents were collected at 21 and 42 d to determine ileal digestible energy (IDE), dry matter and AA digestibilities. Broilers fed diets with AME and dig. AA reductions without enzyme had higher FCR and these diets had lower IDE (P < 0.05). The supplemental enzyme increased total AA digestibility at 21 d; however, no effects were observed at 42 d. The highest total AA digestibility (P < 0.05) was observed when broilers were fed the Control diet whereas the supplemental enzyme compensated the nutrient and energy reductions. The addition of 50 mg/kg of the xylanase-β-glucanase complex in maize-soy diets led to improvements on FCR, IDE and ileal digestibility of dry matter in broilers at 21 and 42 d. The highest energy improvement provided by the supplemental enzyme was observed at 21 d on broilers fed diets with −0.50 MJ/kg AME and −6% dig. AA, being 5.8% higher when compared to those fed the analogous diet without enzyme. [ABSTRACT FROM AUTHOR]

1. An investigation was conducted on the effects of aflatoxin (AFL)-contaminated diets and feed withdrawal periods from 0 to 12 h in broiler chickens at 28 d of age. Both factors can potentially affect liver colour and can cause failure at veterinary inspection in the slaughterhouse. 2. A total of 240, one-d-old female Cobb 500 broiler chickens were fed a common corn-soy pre-starters (d 1–7) and then either a non-contaminated control (CON) or feed with 1 ppm AFL (AFL) from d 8 to 28. The inoculum of AFL had 792 ppb of aflatoxin B1, 35 ppb of aflatoxin B2 and 219 ppb of aflatoxin G1. On d 28, all broilers were weighed and euthanised for necropsy following three different feed withdrawal time periods (0, 6 or 12 h), in a 2 × 3 factorial arrangement. 3. Body weight gain, liver weight and liver fat content decreased as feed withdrawal lengthened, whereas FCR and gallbladder weight increased (P ≤ 0.05). AFL-fed birds had reduced body weight and proportion of liver fat and increased FCR, liver and gallbladder weights (P ≤ 0.05). 4. Livers from fed broilers (0 h withdrawal) showed more lightness (L*) and yellowness (b*) than livers of broilers from 6 or 12 h withdrawal (P ≤ 0.05). The L* and redness (a*) values of livers from broilers fed diets COB were lower than those from AFL fed broilers (P ≤ 0.05). 5. Prolonging pre-slaughter feed withdrawal decreased liver L*, whereas feeding AFL increased liver b*. These findings can be used to support veterinary assessment in slaughterhouses as shackled birds move on line through the inspection site. Since chicken liver is a valuable organ and an indicator of animal health, attention must be paid to these differences to ensure consumer safety. [ABSTRACT FROM AUTHOR]

• Growth performance was improved when broiler chickens were fed maize-soy diets with increasing levels of choline chloride. • Broiler chickens receiving the diet without choline chloride supplementation exhibited the greatest varus (5.7%) and rotated tibia (19.3%) scores. • The average of total choline requirement estimates were 2,516 ppm for body weight gain and 2,533 ppm for feed conversion. An experiment was conducted to evaluate responses of broiler chickens fed a corn-soy (soy protein isolate) choline-deficient diet that was gradually supplemented with choline chloride to a content expected to exceed usual choline concentrations. A total of 525 one-day-old slow feathering male chicks were randomly distributed to 5 treatments and 15 replicates of 7 broiler chickens each. Broilers were fed diets having dietary choline supplementations at 0, 700, 1,400, 2,100 and 2,800 ppm from choline chloride, totalizing formulated concentrations at 727, 1,427, 2,127, 2,827 and 3,527 ppm, respectively. The non-supplemented diet had 736 ppm analyzed choline. Growth performance was weekly evaluated until d 21 when leg deviations were evaluated and liver and tibia were collected. Broiler chicken responses were fitted to quadratic polynomial (QP) and quadratic broken-line (QBL) models. Broilers fed the diet without choline supplementation had the lowest BWG and FI, greaterr FCR as well as greater varus and rotated tibia frequency (P < 0.05) compared to broiler chickens fed diets at any supplemental concentration of choline. Estimations of maximum responses for choline requirements from d 1 to 21 using the QP and QBL regressions were of 2,936 and 2,077 ppm for BWG and 2,827 and 1,627 ppm for FCR, respectively. Broiler chickens fed the diet without choline chloride supplementation had the greatest varus (5.7%) and rotated tibia scores (19.3%) (P < 0.01). The average of total choline requirement estimates obtained were 2,516 ppm for BWG and 2,533 ppm for FCR, whereas 2,202 ppm was needed to minimize the locomotor disorders. [ABSTRACT FROM AUTHOR]

A total of 4,800 one day (d) old Cobb 500 male broilers was used in a study with the objective of evaluating dietary programs formulated with different degrees of restriction in crude protein (CP) and the supplementation of L-valine and L-isoleucine. Four feeding programs (PRG) reflecting different strategies to deliver amino acids (AA) to broilers were used, respectively from d 1 to 7, 8 to 21, 22 to 35 and 36 to 42, as follow: PRG 1, CP restricted to 224, 211, 198 and 184 g/kg with minimum digestible AA to lysine (Lys) ratios only set for total sulfur AA (TSAA) (0.72) and threonine (Thr) (0.65); PRG 2, as PRG 1 without CP restriction with AA ratios to Lys extended to valine (Val) (0.77) and isoleucine (Ile) (0.67); PRG 3, as PRG 2 supplemented with L-Val and PRG 4, as PRG 3 supplemented with L-Ile. Replications of the 4 PRG provided from 1 to 21 d were further divided into the 4 respective PRG given from 22 to 42 d for total of 16 treatments. The study was conducted as a completely randomized block design with 2 time blocks and 24 replications per treatment per block from 1 to 21 d and 12 replications from 22 to 42 d. Overall, there were no effects for time block or interaction between PRG fed from 1 to 21 and 22 to 42 d of age. Performance and processing data demonstrated benefits of formulating diets using minimum ratios of Val and Ile. Body weight gain was higher when both AA were supplemented together (PRG 4). On the other hand, feed conversion ratio (FCR) was improved when the ratios Val and Ile to Lys were obtained without the use of synthetic sources. Carcass yield data was not affected by PRG with the exception of the proportion of abdominal fat that was reduced (P<0.05) when broilers were fed diets with minimum ratios of Val and Ile without using synthetic sources. In conclusion, formulation of diets for broilers without minimum CP level but using AA to Lys ratios as in PRG 2, 3 and 4, allowed competitive growth performance and carcass yield results. Using L-Val and L-Ile led to improved FCR and, therefore, this possibility should be explored to maintain the efficiency of broiler meat production. [ABSTRACT FROM AUTHOR]

• Selenium supplementation improved body weight gain and feed conversion ratio of broilers. • Selenium from hydroxy-selenomethionine that optimized body weight gain was 0.48 ppm. • Effects of dietary selenium on carcass and meat quality of broilers were measured. • Selenium supplementation increased activity of glutathione peroxidase in erythrocytes. Selenium (Se) is essential and usually deficient in corn-soy feeds for broiler chickens. Hydroxy-selenomethionine (OH-SeMet) is a commercial organic source that has not been thoroughly evaluated as a single supplemental source of Se. The objective of this study was to evaluate the increasing dietary Se supplementation from OH-SeMet on broiler growth performance, meat yields, wooden breast (WB) and glutathione peroxidase responses in tissues. A total of 1,500 Cobb vs. Cobb 500 slow feathering one-day-old male chicks were allocated to five treatments with 12 replicates of 25 broilers each in a 3-phase feeding program from d 1 to 42 (0.0, 0.15, 0.30, 0.45 and 0.60 mg/kg of Se supplemented from OH-SeMet). Supplemental Se levels were chosen in order to provide a robust dose-response adjustment and were based on known deficient and excessive dietary contents for broiler chickens. The non-supplemented starter, grower, and finisher feeds had analyzed 0.03, 0.03, and 0.02 mg/kg Se, respectively. At 35 and 42 d of age, five broilers per pen were processed for meat evaluation and scored for WB. Samples from blood, liver, jejunum, and ileum as well as breast meat samples were taken at 42 d for evaluation of glutathione peroxidase (GSH-Px) activity and lipid oxidation (TBARS), whereas breast meat was also analyzed for cooking loss (CL) and water-holding capacity (WHC). Statistical analysis was conducted using the quadratic polynomial regression model. Increasing Se from OH-SeMet led to quadratic increases (P < 0.05) in BWG from d 1 to 42, with optimal concentration at 0.47 mg/kg Se as well as optimized estimations for FCR at 0.42 mg/kg Se. Dietary Se that maximized carcass and breast meat yields at 42 d were 0.41 and 0.48 mg/kg Se, respectively (P < 0.05). Dietary Se that maximized GSH-Px activity in erythrocytes was at 0.27 mg/kg (P < 0.05). No effects of Se were observed on WB scores at 35 and 42 d of age, CL and WHC as well as on TBARS in intestine, liver and breast muscle samples (P > 0.05). Supplementation of Se from OH-SeMet in corn-soy feeds improved broiler performance, carcass and breast yields. Average Se that optimized BWG was 0.48 mg/kg, whereas 0.46 mg/kg was needed for carcass and 0.40 mg/kg for breast yield. These are total Se contents acceptable in the European Union and frequently below commercially used contents in countries that do not have a limit on minerals in feeds. [ABSTRACT FROM AUTHOR]

Wooden breast (WB) myopathy was investigated in broilers fed varying energy and protein at early ages. Correlation analyses were conducted between echogenicity of ultrasound images (US) of breast muscle from live birds and WB after slaughter. A total of 1,000 Cobb 500 one-day-old male chicks were fed on five dietary programs with eight replicates of 25 birds each, in a completely randomized design. Control feeds (commercially used ME and ideally balanced amino acids) or low-density feeds (low EP, with reductions of 50 kcal/kg ME and 0.20% dig. Lys compared to the control) were formulated. Feeds were provided in different periods: 1 to 7 d, 8 to 14 d, 15 to 21 d or 22 to 28 d. All broilers were fed a common basal diet thereafter until 49 d. Images using US were obtained once a week from all individuals and WB scored from one slaughtered bird per replication (0, normal; 1, mild hardening in the upper breast muscle; 2; moderate hardening in the upper and/or lower breast muscle; 3, severe hardening; 4, severe hardening with hemorrhagic lesions and yellow fluid). Blood was collected for enzyme investigation from the weekly slaughtered bird. Broilers had lower BWG and higher FCR when fed low EP feeds, regardless of the period fed when compared to the control (P < 0.001). Growth compensation, however, occurred afterwards such that all birds presented similar performance at the end. At 14, 21, and 28 d, broilers previously fed low EP feeds had lower WB scores (P < 0.001) compared to birds fed the control; however, both groups presented increased WB scores after 28 d. Wooden breast was positively correlated with breast echogenicity at 21 d (r = 0.31), 28 d (r = 0.43), 35 d (r = 0.21) and 42 d (r = 0.39). In conclusion, dietary energy and protein affected the development of WB scores in broilers and breast US images can be used as an early predictor of WB. [ABSTRACT FROM AUTHOR]

Two experiments (Exp.) were conducted to evaluate effects of a lysophospholipid-based bio-emulsifier (LPL) on growth performance, nutrient digestibility and energy utilization of broilers as well as the return on investment (ROI). In Exp. 1, 392 chicks were housed in battery cages in a completely randomized design with 8 treatments and 7 replicates of 7 birds each from d 0 to 21 posthatch. In Exp. 2, 1,400 chicks were allocated in floor pens and fed the same 8 treatments, with 7 replicates and 25 birds each from d 0 to 43 posthatch. Treatments consisted of 6 degummed soybean oil-based diets: positive control (PC1) ; PC1 formulated with 500 g/ton LPL (PC1+LPL on top) ; PC1 formulated with 60 kcal LPL matrix (PC1+LPL60) ; PC1 formulated with 100 kcal LPL matrix (PC1+LPL100) ; and two negative controls NC-60 and NC-100 with reductions of 60 and 100 kcal/kg ME, respectively. Two other diets were formulated with acid soybean oil: positive control (PC2) and PC2 formulated with 60 kcal LPL matrix (PC2+LPL60). In Exp. 1, performance was evaluated from d 0 to 21, ME and ileal digestibility of DM, CP and energy were determined on d 21. In Exp. 2, growth performance was evaluated from d 0 to 42, and on d 43 carcass and abdominal fat yields were calculated. There were no effects of soybean oil sources in any parameter. Inclusion of LPL increased (P < 0.05) BW gain and ileal digestibility of DM, fat and CP. Broilers fed the PC1+LPL on top diet had increased (P < 0.05) performance, ileal digestibility and energy utilization as well as decreased abdominal fat compared to NC-60 or NC-100. The use of LPL on top had a ROI of 8:1 vs. PC1, considering the gains in revenue of the slaughtered broilers in relation to the investment with LPL in feed. In conclusion, a lysophospholipid-based bio-emulsifier increased performance, digestibility and return on investment of broilers fed standard or reformulated diets. [ABSTRACT FROM AUTHOR]

• The regression method allowed to determine metabolizable energy of insect meal and tilapia byproduct meal for broilers. • The metabolizable energy of Tenebrio molitor larvae meal for broilers was 21.93 MJ/kg. • The metabolizable energy of tilapia byproduct meal for broilers was 14.29 MJ/kg. A study was conducted to determine ileal digestible energy (IDE), metabolizable energy (ME), and nitrogen-corrected ME (ME n) of Tenebrio molitor larvae meal and Nile tilapia byproduct meal for broiler chickens using the regression method. A total of 315 slow feathering Cobb 500 male broilers were fed 5 experimental diets with 9 replicate cages of 7 birds each, in a completely randomized design. Broilers were fed a maize-soybean meal reference diet (RD) and 4 test diets (TD) from d 14 to 21 posthatch. The TD consisted of Tenebrio molitor larvae meal and tilapia byproduct meal that partly replaced the energy sources in the reference diet at 100 or 200 g/kg and 75 or 150 g/kg, respectively, such that equal ratios were maintained for all energy containing ingredients across all experimental diets. Excreta samples were collected twice daily from d 19 to 21, and ileal digesta were collected on d 21. Apparent ileal digestibility of DM, N, amino acids as well as metabolizability coefficients of DM, N, and energy were calculated. Addition of Tenebrio molitor larvae meal to the RD linearly increased (P < 0.05) ileal and total tract of DM and N digestibilities as well as IDE, ME, and ME n. For diets with Tenebrio molitor larvae meal substitution, regression equations were IDE = 21.52x – 0.0234, ME = 21.93x – 0.0189, and ME n = 20.62x – 0.0241. Addition of tilapia byproduct meal to the RD linearly decreased (P < 0.05) ileal and total tract coefficients of DM and IDE, ME, and ME n , as well as ileal digestibility of amino acids (P < 0.001). The equations for the tilapia byproduct meal diets were IDE = 12.49x – 0.0264, ME = 14.29x – 0.0152, and ME n = 11.94x – 0.0129. In conclusion, the current study showed that broiler chickens can utilize a considerable amount of energy and amino acids from insect meal or fish meal. The IDE, ME, ME n values (MJ/kg of DM) were 21.52, 21.93 and 20.62 for Tenebrio molitor larvae meal, and 12.49, 14.29 and 11.94 for tilapia byproduct meal, respectively. [ABSTRACT FROM AUTHOR]