Digestible Lys Research Articles

Interactive effects of dietary energy levels with amino acid density on growth performance and optimal digestible Lys to energy ratio of male broiler chickens

A total of 2,400 day-old off-sex male Ross 308 chicks were used in a 4 × 3 factorial array (8 replicates with 25 birds per replicate) to determine the interactive effects of dietary metabolizable energy (ME) and amino acid (AA) densities on productive traits of broiler chickens reared to 42 d of age. The experimental factors were 4 ME levels (control, -50, -100, -150 kcal) and 3 digestible AA levels (control, +3.0 and +6.0%). Diets were fed for starter (0-10 d), grower (11-24 d), finisher (25-35 d), and withdrawal (36-42 d) phases, with consistent reduction of ME and increase in AA density for each phase. Overall, ME reduction did not compromise final body weight (BW; d 42). However, when ME was reduced by 50 kcal, only the diets with +6% AA density improved BW, resulting in an interaction between ME and AA levels (P < 0.05). Reducing ME and increasing AA densities independently increased total feed intake (P < 0.01). An interaction between ME and AA density on feed conversion ratio (FCR) was observed where increasing AA density at both +3.0 and +6.0% levels at control ME reduced FCR, but with reduced ME diets, FCR was reduced only at +6% AA density (P < 0.01). Quadratic broken line models estimated a digestible Lys to ME ratio (mg Lys/1,000 kcal ME) of 474 and 407 in starter and grower diets, respectively, to optimize both BW and FCR. However, in finisher phase a ratio of 363 could only be predicted for optimal FCR and in withdrawal a ratio of 349 to optimize BW. In summary, these results indicate that the interaction between ME and AA densities affects the productive traits of broiler chickens. Increasing AA density at control ME density improves FCR, while reduced ME diets require higher AA density to improve FCR. Quadratic broken line models suggest specific digestible Lys to ME ratios for optimizing BW and FCR across different phases of the production cycle.

Apparent ileal amino acid digestibility, gut morphometrics, and gene expression of peptide and amino acid transporters in broiler chickens fed low-crude-protein diets supplemented with crystalline amino acids with soybean meal, canola meal, or corn DDGS as protein feedstuffs.

We investigated the impact of using canola meal (CM) or corn distillers dried grain soluble (cDDGS) in place of soybean meal (SBM) in low-crude-protein diets supplemented with amino acids (AA) on AA digestibility, gut morphometrics, and AA transporter genes in broiler chicken. On day 0, 540 Cobb 500 male broilers were allocated to six diets in 36-floor pens. The positive control (PC) was a corn-SBM diet with adequate crude protein (CP). The CP level of negative control (NC) was decreased by 45 and 40 g kg-1 relative to PC for grower and finisher phases, respectively. The subsequent two diets had the same CP levels as NC but with cDDGS added at 50 or 125 g kg-1. The last two diets had the same CP as NC but with CM added at 50 or 100 g kg-1. Dietary CP reduction in corn-SBM diets increased (P < 0.05) the digestibility of Lys (88.5%), Met (90.7%), Thr (77.4%), Cys (80.7%), and Gly (84.7%). Increasing levels of cDDGS linearly decreased (P < 0.05) the digestibility of Asp, Cys, Glu, and Ser, whereas increasing CM level linearly decreased (P < 0.05) the digestibility of Cys, Pro, and Ser. The CP reduction in corn-SBM diets produced downward expression of peptide transporter1 and decreased (P < 0.05) absolute pancreas and ileum weight and length of jejunum and ileum. Partial replacement of SBM with alternative protein feedstuffs (cDDGS or CM) in low-CP diets had minimal effects on AA digestibility and mRNA levels of peptides and AA transporters. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

212 Effect of Low Crude Protein Diets in Young Pigs When Using Crystalline Isoleucine and Leucine

Abstract An experiment was conducted to evaluate the response to low crude protein (CP) while maintaining equal standardized ileal digestible (SID) LYS and equal SID amino acid-to-LYS ratios (including MET+CYS, THR, TRP, VAL, ILE, and LEU) to test whether the addition of LEU and ILE allowed CP to decline below 19.5% without impacting performance when SID LYS was 1.35%. For the experiment, pigs (n = 288; ~22 days of age, 6.29 ± 0.71 kg BW, 8 reps/treatmentt, 6 pigs/pen) were stratified by BW and randomly allotted to one of 6 treatments in a randomized complete block design. Treatments had a fixed SID LYS of 1.35% and CP ranging from 21 to 17.25% in 0.75% increments. Experimental diets were fed for 21 days, and BW and feed disappearance were recorded. Visual fecal scores (1 = normal to 4 = watery) and visual pig appearance scores (1 = pale and hairy to 4 = normal color and well-rounded muscle) were assessed on ordered likert scales to determine the probabilities of observing a more normal stool quality and a worse visual appearance, respectively. Performance data were analyzed as a general linear model. Stool quality and visual appearance were analyzed as a generalized linear mixed model. Contrasts were used to test linear and quadratic effects of dietary CP. Results of the experiment are presented in Table 1. With constant SID Lys of 1.35%, reducing CP from 21.00 to 17.25% resulted in an increase then a decrease (linear, P &amp;lt; 0.005; quadratic, P &amp;lt; 0.005) in BW, ADG, ADFI, and gain:feed. Average daily gain and ADFI began decreasing when CP decreased below 20.25%, whereas body weight and gain:feed began decreasing once CP was below 19.50%. There was a difference detected amongst treatments in stool quality, but this was not due to changes in crude protein levels of the diets. This suggests that protein fermentation was not directly impacting stool quality in these pigs. Decreasing dietary CP also linearly (P &amp;lt; 0.05) and quadratically (P &amp;lt; 0.05) affected the visual appearance of the pigs in a similar manner to performance. At the least levels of crude protein, pigs had a greater probability of having more coarse hair and paler skin suggesting that a nutritional stress response may be occurring. These results indicate that the addition of ILE and LEU to the formula do not allow CP to decrease below 19.5% without affecting performance when SID LYS is 1.35 in young pigs.

208 Effect of SID LYS Level with Constant Non-Essential Amino Acids

Abstract Many investigations on the effect of low protein diets reduce crude protein (CP) and have a constant standardized ileal digestible (SID) LYS resulting in reductions in ADG, ADFI, and gain:feed is some cases. This experiment was conducted to determine the impact of maintaining constant non-essential amino acids and changing SID LYS and other essential amino acids. For the experiment, 288 pigs (~22 d of age, 6.61 ± 0.95 kg, 8 replicates/treatment, 6 pigs/pen) were stratified by body (BW) and randomly allotted to one of 6 treatments in a randomized complete block design. Non-essential amino acids were fixed in all diets and synthetic amino acids were added to increase SID LYS from 1.15% to 1.4% while maintaining constant ratios of MET+CYS, THR, TRP, VAL, and ILE to LYS. Diets were corn, wheat, barley, and soy based with 1.1% corn starch in the least SID LYS diet. Synthetic amino acids were added to the diet at the expense of corn starch to maintain non-essential amino acid levels. The CP ranged from 17.8% when SID LYS was 1.15% and 18.6% when SID LYS was 1.4%. Experimental diets were fed for 21 d. Body weight, feed disappearance, visual fecal scores, and visual piglet scores were measured. Visual fecal scores (1 = normal to 4 = watery) and visual pig appearance scores (1 = pale and hairy to 4 = normal color and well-rounded muscle) were assessed on ordered likert scales to determine the probabilities of observing a more normal stool quality and a worse visual appearance, respectively. Performance data were analyzed as a general linear model. Stool quality and visual appearance were analyzed as a generalized linear mixed model. Contrasts were used to test linear and quadratic effects of dietary SID LYS. Results of the experiment are presented in Table 1. Increasing SID LYS with constant non-essential amino acids did not affect ADG or BW. The ADFI was linearly decreased (P &amp;lt; 0.1) and gain:feed was linearly increased (P &amp;lt; 0.0001) with increasing SID LYS (Table 1). Stool quality was not affected. Visual appearance of the pigs was quadratically affected (P &amp;lt; 0.05) by changing SID LYS. Pigs that had consumed diets with the lowest or highest SID LYS had the best visual appearance (lowest probability). The results of the current experiment differ suggest SID LYS may regulate feed intake and nutrient efficiency, but BW gain is not affected when non-essential amino acids are held constant. This differs from cases where CP is reduced, which results are decreased growth in many cases.

Growth performance and nutrient digestibility of broiler chickens as affected by a novel protease

Two experiments evaluated the addition of an exogenous sfericase protease in broiler diets. Experiments were run (Exp1 and Exp2) with 1,848 and 2,100 one-day-old male chicks being allocated into 84 floor pens with 14 replicates of 22 and 25 birds each, respectively. The studies were conducted in completely randomized designs. In Exp1, Standard diets were formulated with energy and AA at marginally lower levels than usual by the Brazilian integration such that broilers were expected to grow at comparatively reduced rates to the industry whereas in Exp2, the Standard diets were formulated using energy and AA as usual by the Brazilian integrations such that broilers were expected to grow comparable to industry rates. Standard diets had ideally balanced amino acids (AA). Matrix diets, in contrast, had reductions of 6% digestible lysine and of 20 kcal AME/kg compared to the Standard. Matrix diets were supplemented with an sfericase protease at 0, 10,000, and 30,000 New Feed Protease units (NFP)/kg. Outcomes showed no interaction between diet and protease in any of the experiments. However, broilers fed Standard diets had higher cumulative body weight gain (BWG) to 35 and 42 d when compared to Matrix fed birds whereas FCR were worse for birds fed the Matrix diets at 35 d in EXP1 and at 35 and 42 d in EXP2. Improvements in FCR were observed when the sfericase protease was added throughout all ages in EXP1 with a beneficial trend (P&amp;lt;0.067) observed in the cumulative FCR at 42 d in EXP2. The ileal digestible crude protein (IDCP) was significantly higher for birds fed Standard feeds in EXP1 with no other differences in digestibility found in any of the experiments. Protease addition led to improvements in ileal digestibility of dry matter (IDM) and IDCP (P &amp;lt; 0.05) compared to no protease addition in EXP1 as well as in ileal digestibility of energy (IDE) when 30,000 protease units were added. The present report demonstrates that the novel sfericase protease was successful in compensate broiler performance when reductions of 6% digestible Lys and 20 kcal/kg AME were imposed. This compensation, however, seemed more notable when birds were fed diets formulated to support moderate rather than maximum growth and having animal protein in the feed formula.

PSIII-18 Effect of Increasing L-Lysine-HCl and Amino Acid Ratios on Performance of Finishing Pigs from 109 to 129 Kg

Abstract A total of 1,789 pigs (PIC; 337×1050; initial BW 108.9 ± 1.14 kg) were used to determine the effects of increasing L-Lys-HCl and AA ratios on performance of late finishing pigs fed corn-soybean meal diets without DDGS. The study used 2 groups of pigs and each study lasted 18 and 27 d, respectively. Pigs were housed in mixed gender pens with 20 to 25 pigs/pen and 19 replications/treatment (10 and 9 replications/group, respectively). Pens of pigs were blocked by BW and randomly allotted to 1 of 4 dietary treatments. Treatment diets were formulated to 0.70% digestible Lys and consisted of low, medium, or high levels of feed-grade AA and moderate or high AA ratios relative to Lys. Low, medium and high feed-grade AA treatments had increased L-Lys-HCl (0.15, 0.30 and 0.39%) replacing soybean meal to achieve CP levels of 13.6, 12.0, and 11.0. Minimum AA:Lys ratios were 53% Ile, 128% Leu, 58% Met&amp;Cys, 66% Thr, 18.5% Trp, 68% Val, and 34% His in Moderate AA ratio diets and 60% Ile, 128% Leu, 60% Met&amp;Cys, 70% Thr, 21.2% Trp, 72% Val, and 33% His for the high AA ratio treatment. Overall, there was a marginally significant increase in ADFI (quadratic, P = 0.097) observed in pigs fed medium feed-grade AA and moderate AA ratios. Treatment diets had no effect on ADG or G:F. At the end of group 2, carcass data was collected with no differences (P &amp;gt; 0.10) observed for HCW, carcass yield, backfat depth, loin depth or percentage lean. In summary, differing levels of feed-grade AA and AA ratios used in this study did not impact growth performance or carcass characteristics of late finishing pigs with the exception of a marginally significant increase in ADFI.

Assessment of digestible lysine requirements in lipopolysaccharide-challenged pigs.

To evaluate the effect of an Escherichia coli lipopolysaccharide (LPS) challenge on the digestible lysine (Lys) requirement for growing pigs, a nitrogen (N) balance assay was performed. Seventy-two castrated male pigs (19 ± 1.49 kg body weight [BW]) were allocated in a 2 × 6 factorial design composed of two immune activation states (control and LPS-challenged) and six dietary treatments with N levels of 0.94, 1.69, 2.09, 3.04, 3.23, and 3.97% N, as fed, where Lys was limiting, with six replicates and one pig per unit. The challenge consisted of an initial LPS dose of 30 μg/kg BW via intramuscular (IM) injection and a subsequent dose of 33.6 μg/kg BW after 48 h. The experimental period lasted 11 d and was composed of a 7-d adaptation and a subsequent 4-d sampling period in which N intake (NI), N excretion (NEX), and N deposition (ND) were evaluated. Inflammatory mediators and rectal temperature were assessed during the 4-d collection period. A three-way interaction (N levels × LPS challenge × time, P < 0.05) for IgG was observed. Additionally, two-way interactions (challenge × time, P < 0.05) were verified for IgA, ceruloplasmin, transferrin, haptoglobin, α-1-acid glycoprotein, total protein, and rectal temperature; and (N levels × time, P < 0.05) for transferrin, albumin, haptoglobin, total protein, and rectal temperature. LPS-challenged pigs showed lower (P < 0.05) feed intake. A two-way interaction (N levels × LPS challenge, P < 0.05) was observed for NI, NEX, and ND, with a clear dose-response (P < 0.05). LPS-challenged pigs showed lower NI and ND at 2.09% N and 1.69 to 3.97% N (P < 0.05), respectively, and higher NEX at 3.23% N (P < 0.05). The parameters obtained by a nonlinear model (N maintenance requirement, NMR and theoretical maximum N deposition, NDmaxT) were 152.9 and 197.1 mg/BWkg0.75/d for NMR, and 3,524.7 and 2,077.8 mg/BWkg0.75/d for NDmaxT, for control and LPS-challenged pigs, respectively. The estimated digestible Lys requirements were 1,994.83 and 949.16 mg/BWkg0.75/d for control and LPS-challenged pigs, respectively. The daily digestible Lys intakes required to achieve 0.68 and 0.54 times the NRmaxT value were 18.12 and 8.62 g/d, respectively, and the optimal dietary digestible Lys concentration may change depending on the feed intake levels. Based on the derived model parameters obtained in the N balance trial with lower cost and time, it was possible to differentiate the digestible Lys requirement for swine under challenging conditions.

Effects of breeds and dietary nutrient levels on expression patterns of paired box genes and myogenic regulatory factors in pigs

ABSTRACT Two experiments were conducted to investigate the effects of different breeds and dietary nutrient levels on expressions of paired box (Pax) genes and myogenic regulatory factors (MRFs) in pigs. Thirty Large White (LW) barrows and thirty Chenghua (CH, a native breed of China) barrows were performed in experiment 1. Results exhibited that in the CH pigs the abundances of Pax3 at 105 and 220 d of age, Mrf4 at 63 d of age, Myf5 and Mrf4 at 220 d of age were higher than those in the LW pigs (p < 0.05). Meanwhile, the expressions of MyHC-І and ІІa in the CH pigs were upregulated, and the abundance of MyHC-ІІb were downregulated compared with those in the LW pigs at 105 and 220 d of age (p < 0.05). Moreover, the meat quality of the CH pigs was better than in the LW pigs (p < 0.05). In experiment 2, sixty LW pigs were randomly assigned to two dietary treatments meeting their nutrient requirements (NRC) or a diet with moderately reduced digestible energy, crude protein and Lys level by 560 kJ/kg, 1.48% and 0.34%, respectively (LOW diet). The results showed that the reduced dietary nutrient level increased (p < 0.05) the expressions of MyoG and Mrf4 at 105 d of age, Pax3, Myf5, and Mrf4 at 220 d of age, and upregulated (p < 0.05) the abundance of MyHC-ІІa at 105 and 220 d of age in LW pigs. In addition, a decrease in dietary nutrient level improved the meat quality in LW pigs (p < 0.05). Collectively, the expressions of Pax genes and MRFs were markedly different between the CH and LW pigs. The CH pigs exhibited higher expression levels of Pax3, Myf5, Mrf4, MyHC-І and ІІa, which may improved the meat quality. A decrease in dietary nutrient level upregulated the abundances Pax3, Mrf4, Myf5, MyoG, and MyHC-ІІa, and might enhance the meat quality in the LW pigs.

Effects of amino acid levels during rearing on Cobb 500 slow-feathering broiler breeders: 2. Reproductive performance

Crude protein and amino acid (AA) content in rearing diets affect body composition and reproductive performance. This study evaluated the effects of 4 dietary AA levels during rearing on BW, egg production and composition, fertility, hatchability, and embryo mortality up to 65 wk of age on Cobb 500 slow-feathering (SF) broiler breeders. The treatments consisted in 80% (low-AA), 90% (moderate-AA), 100% (standard-AA), and 110% (high-AA) of the AA recommendations for Cobb 500 SF pullets from 5 to 24 wk. AA was guided by an ideal protein profile based on digestible Lys. A total of 1,360 pullets and 288 Cobb MV cockerels were randomly placed in 16 pullets and 16 cockerel floor-pens. At 22 wk, 1,040 females and 112 males were transferred into 16-floor pens in a laying house. BW increased linearly (P < 0.01) as AA augmented at 25, 36, and 40 wk. No effects (P > 0.05) at the onset of lay were observed. Moderate-AA and standard-AA resulted in the best hen-housed egg production (HHEP) at 65 wk with 174.3 and 176.5 eggs, respectively. The optimum level of AA for HHEP at 65 wk was estimated (P < 0.001) in 96.7% and 94.7% by the quadratic and broken line models, respectively. Overall, the lightest egg weight (P = 0.022) was obtained with 89%AA during rearing, and the heaviest eggs (P < 0.001) were found at 54 wk. Response surface regression indicated linear effects on albumen and yolk percentages (P < 0.01) increasing and decreasing, respectively, as AA levels augmented; consequently, AA had a negative linear effect on Y:A ratio (P = 0.004) with quadratic effects (P < 0.01) of age (R2 = 0.92). No statistical effect of treatments was observed in fertility (P > 0.05), but AA had a quadratic effect (P = 0.046) on hatchability up to 50 wk of age with 97% as optimum, and decreased linearly (P = 0.004) from 51 to 65 wk. A few effects of treatments (P < 0.05) on embryo mortality were observed. In conclusion, AA levels during rearing affect broiler breeder reproductive performance.

130 Assessing current phytase release values for calcium, phosphorus, amino acids and energy in diets for growing pigs

Abstract A total of 2,268 pigs (PIC 337×1050, initially 28.5±2.3 kg) were used in a 55-d growth study. On d 0, pens of pigs were blocked by body weight and randomly allotted to 1 of 6 dietary treatments with 27 pigs per pen and 14 pens per treatment. Treatments were fed in 2 different phases containing 1.05 and 0.89% SID Lys, respectively. The 6 treatments consisted of a control with no phytase and inorganic P from monocalcium P, or 5 diets with 1,500 phytase units (FYT/kg; Ronozyme HiPhos 2,500; DSM Nutritional Products, Inc., Parsippany, NJ) assuming supplier-provided nutrient release values for Ca and P (CaP), Ca, P, and AA (CaPAA), Ca, P, AA, and half of the suggested net energy (CAPAA+halfNE), Ca, P, AA, and full NE (CaPAA+fullNE) and no nutrient release (None). The assumed release values were 0.146% STTD P, 0.102% STTD Ca, 41.8 kcal/kg of NE, and 0.0217, 0.0003, 0.00886, 0.0224, 0.0056, 0.0122, and 0.0163% digestible Lys, Met, Met + Cys, Thr, Trp, Ile, and Val, respectively. All diets within phase were corn-soybean meal-based and contained a STTD Ca:STTD P ratio of 1.60:1. Data were analyzed as a randomized complete block design for a one-way ANOVA using the lmer function from the lme4 package in R. Overall (d 0 to 55), there was no evidence for differences in ADG or ADFI. However, pigs fed the diet containing 1,500 FYT/kg assuming no nutrient release had increased (P&amp;lt; 0.05) G:F compared to pigs fed diets containing 1,500 FYT/kg assuming either CaP or CaPAA+fullNE release, with others intermediate. Based on diet formulation and using supplier recommended phytase release values, all pigs should have had similar performance. However, pigs fed full matrix release values for CaPAA+fullNE had decreased (P&amp;lt; 0.05) G:F, suggesting that full matrix release values, especially energy, may be too aggressive and resulted in diets contributing less nutrients than needed to optimize performance.

Changes in body composition and meat quality in response to dietary amino acid provision in finishing broilers

In order to control and optimize chicken quality products, it is necessary to improve the description of the responses to dietary amino acid (AA) concentration in terms of carcass composition and meat quality, especially during the finishing period. The aim of this study was to investigate the effects of Lysine (Lys, i.e. a limiting AA used as reference in AA nutrition) and AA other than Lys (AA effect). In total, 12 experimental diets were formulated with four levels of digestible Lys content (7, 8.5, 10 and 11.5 g/kg) combined with either a low (AA−), adequate control (AAc) and high (AA+) amount of other essential AA (EAA) expressed as a proportion of Lys. They were distributed to male Ross PM3 from 3 to 5 weeks of age. No significant AA×Lys interaction was found for growth performance or carcass composition. Body weight and feed conversion ratio were significantly improved by addition of Lys but were impaired in broilers receiving the AA− diets, whereas breast meat yield and abdominal fat were only affected by Lys. No additional benefit was found when the relative amount of other EAA was increased. There was a significant AA×Lys interaction on most of the meat quality traits, including ultimate pH, color and drip loss, with a significant effect of both AA and Lys. For example, AA− combined with reduced Lys level favored the production of meat with high ultimate pH (>6.0), dark color and low drip loss whereas more acid, light and exudative meat (<5.85) was produced with AA+ combined with a low Lys level. In conclusion, growth performance, carcass composition and meat quality are affected by the levels of dietary Lys and AA in finishing broilers. In addition, interactive responses to Lys and AA are found on meat quality traits, leading to great variations in breast pHu, color and drip loss according AA balance or imbalance.

126 Efficiency of Utilizing Standardized Ileal Digestible Lys for Whole Body Protein Retention in Pregnant Gilts during Early, Mid and Late Gestation.

126 Efficiency of Utilizing Standardized Ileal Digestible Lys for Whole Body Protein Retention in Pregnant Gilts during Early, Mid and Late Gestation.

Effect of Dietary Lysine Regimens on Growth Performance and Meat Composition in Aseel Chicken

ABSTRACT A study was designed with the objective, to evaluate the effect of dietary lysine (Lys) regimens on growth performance and meat composition of Aseel chicken. In total, 540 day old chicks, 180 from each variety, were randomly assigned to 9 experimental groups in a 3 (Varieties: Mianwali (MW), Peshawari (PW), and Lakha (LK)) × 3 (Lys regimens: L1, L2 and L3:1.35, 1.30 and 1.25%) factorial arrangement under randomized complete block design (RCBD) with sex as block. Each experimental group was replicated 6 times with 10 birds in each with average weight of 29 gram. Feed intake (FI), weight gain (WG) and feed:gain ratio (F:G) parameters of growth performance and Dry Matter (DM), Ash, Crude Protein (CP) and Ether Extract (EE) parameters of meat composition were evaluated. The results indicated better (p=0.0006) WG and (p=0.0006) F:G was observed in MW verities. Among different Lys regimens, higher and medium level in the diet improved WG (p<.0001), F:G (p<.0001) and reduced (p=0.0001) FI. Similarly increased (p<.0001; 0.0150) ash content in thigh and breast due to increased level of lysine in the early life period. Dry matter was found to be higher (p=0.0036) only in medium Lys regimen, whereas meat CP was observed to be higher (p=0.0064) in control diet. It was concluded that, 1.30% digestible Lys level regimen can be used to improve the early growth rate of Aseel chicken. Similarly, Mianwali variety due to its better early growth can be used as a meat type chicken.

Estimation of broiler responses to increased dietary methionine hydroxy analogue [DL-2-hydroxy-(4-methylthio) butanoic acid] using linear and nonlinear regression models

As the first limiting amino acid in corn-soy 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 × 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 3,150kcal/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%.

Fermentation and enzymatic treatment of pea for turkey nutrition

The present study was conducted to investigate how fermentation (FE) and enzymatic treatment (ET) of pea affect standardized ileal digestibility (SID) of nutrients in diets with peas as the only protein source, and evaluate the consequences of inclusion of different pea products in turkey diets (100 g/kg) on growth performance and bird health. For FE process, Pisum sativum L. was mixed with water (1:1) containing 4.9 × 108Bacillus subtilis and licheniformis spores/kg pea (BIOPLUS 2B®, Chr. Hansen, Denmark). The prepared dough was fermented for 48 h at 30 °C. For ET, the dough water contained three enzymes, AlphaGal™ (α-galactosidase – Kerry, USA), RONOZYME® ProAct and VP (protease and pectinases, respectively – DSM, Switzerland). The dough (500 g/kg DM) was incubated for 24 h at 30 °C. Both processes reduced α-galactosides, phytate, trypsin inhibitor activity and resistant starch in peas. For standardized ileal digestibility (SID) assay, 288 turkeys were assigned to 24 pens and received four experimental diets including native (NP), fermented (FEP) and enzymatically treated peas (ETP) as well as a N-free diet (all supplemented with vitamins and minerals). The ETP had better SID of protein, Glu, Phe and Val compared with FEP and NP. Enzymatic treatment of pea also improved standardized ileal digestibility of Ala, Gly, His, Ilu, Leu and Lys (P ≤ 0.05), however digestibility of these nutrients in fermented pea were similar to other two types of pea (P > 0.05). Both processes drastically improved ileal digestibility of starch (P ≤ 0.05). For performance trial, 960 turkeys were allocated into 60 pens and received 4 different diets consisted of a basal mash wheat-SBM diet (CON) and there experimental diets which were prepared by inclusion of each pea products NP (NPD), FEP (FEPD) and ETP (ETPD) in the basal diet at the rate of 100 g/kg. The experiment lasted 105 d. In general, in the most time periods of the performance trial, birds received ETPD or FEPD diets showed better growth performance than those fed NPD diet, while birds in ETPD group displayed similar performance to those fed CON diet. At the end of the trial, birds fed CON and ETPD diets had the best FCR and birds which received NPD diet had the worst one (P ≤ 0.05). Birds in ETPD group showed the best footpad dermatitis score and turkeys in the NPD group had the worst score (P ≤ 0.05). The footpad dermatitis scores for turkeys in CON and FEPD groups were identical and considerably different from those in ETPD and NPD groups (P ≤ 0.05). In conclusion, both processes could improve the nutritional quality of pea by reduction in ANF and increasing ileal starch digestibility. Furthermore, ET process considerably improved SID of protein and AAs in pea. Inclusion of ETP in turkey diets (100 g/kg) demonstrated neither positive nor negative impact on growth performance, while it remarkably improved footpad dermatitis score. The present data shows the feasibility of these processes, particularly ET, for improving the nutritional quality of pea as a protein source for turkey diets.

A comparative study on the effects of dietary sunflower hulls on growth performance and digestive tract traits of broilers and pullets fed a pullet diet from 0 to 21 days of age

The effects of the inclusion of sunflower hulls (SFH) in the diet on growth performance, coefficient of total tract apparent retention (CTTAR) of nutrients, gastrointestinal tract (GIT) traits and short chain fatty acid (SCFA) concentration in the cecum were studied in chicks from 0 to 21 d of age. Treatments consisted in the combination of two chicken lines (female broilers vs. pullets) and two levels of SFH inclusion (0 vs. 30g/kg). The control diet contained 11.94MJ AMEn, 191g crude protein, 9.8g digestible Lys and 101g neutral detergent fiber/kg. The experimental diet included 30g SFH/kg at the expense (wt:wt) of the control diet. Growth performance was better (P<0.001) in broilers than in pullets at all ages. Moisture content of the excreta was lower (P<0.001) in pullets than in broilers at 21 d of age but an opposite effect was observed at 9 d. At 9 d of age, nutrient retention (P<0.001) and AMEn of the diet (P<0.01) were higher in broilers than in pullets but at 21 d of age the only difference detected was for N retention (P<0.001). In absolute terms (g or cm) broilers had heavier (P<0.001) digestive organs and longer small intestine (SI) and cecum than pullets. In relative terms, however, the GIT (P=0.062), proventriculus (P<0.001), gizzard (P<0.001) and pancreas (P<0.01) were heavier at 21 d, and the SI and the cecum were longer (P<0.001) at both ages in pullets. SFH inclusion did not affect growth performance or organ weights at any age but increased the absolute length of the SI and cecum and the AMEn of the diet at 21 d of age (P<0.05). At 21 d of age, fiber inclusion reduced moisture content of the excreta in broilers but no effects were observed in pullets (P<0.05 for interaction). The pH of the GIT and the concentration of SCFA in the cecum were not affected by chicken line or SFH inclusion. Villus height and crypt depth were higher (P<0.001) in broilers than in pullets but were not affected by SFH inclusion. In summary, broilers showed greater growth performance and nutrient retention at 9 d of age and better ileum absorptive capacity at 21 d than pullets. The dilution of the diet with 30g SFH/kg did not affect chick performance and in fact, improved the AMEn of the diet in both chicken lines at 21 d of age.

Digestible lysine requirements of male broilers from 1 to 42 days of age reassessed.

Three experiments were conducted separately to estimate the digestible Lys (dig. Lys) requirements of Cobb × Cobb 500 male broilers using different statistical models. For each experiment, 1,200 chicks were housed in 48 floor pens in a completely randomized design with 6 treatments and 8 replicates. Broilers were fed diets with increasing dig. Lys levels from 1 to 12 d (Exp. 1), from 12 to 28 d (Exp. 2), and 28 to 42 d (Exp. 3). Increasing dig. Lys levels were equally spaced from 0.97 to 1.37% in Exp. 1, 0.77 to 1.17% in Exp. 2, and 0.68 to 1.07% in Exp. 3. The lowest dig. Lys diets were not supplemented with L-Lysine and all other essential AA met or exceeded recommendations. In Exp. 3, six birds per pen were randomly selected from each replication to evaluate carcass and breast yields. Digestible Lys requirements were estimated by quadratic polynomial (QP), linear broken-line (LBL), quadratic broken-line (QBL), and exponential asymptotic (EA) models. Overall, dig. Lys requirements varied among response variables and statistical models. Increasing dietary dig. Lys had a positive effect on BW, carcass and breast yields. Levels of dig. Lys that optimized performance using QP, LBL, QBL, and EA models were 1.207, 1.036, 1.113, and 1.204% for BWG and 1.190, 1.027, 1.100, and 1.172% for FCR in Exp. 1; 1.019, 0.853, 0.944; 1.025% for BWG and 1.050, 0.879, 1.032, and 1.167% for FCR in Exp. 2; and 0.960, 0.835, 0.933, and 1.077% for BWG, 0.981, 0.857, 0.963, and 1.146% for FCR in Exp. 3. The QP, LBL, QBL, and EA also estimated dig. Lys requirements as 0.941, 0.846, 0.925, and 1.070% for breast meat yield in Exp. 3. In conclusion, Lys requirements vary greatly according to the statistical analysis utilized; therefore, the origin of requirement estimation must be taken into account in order to allow adequate comparisons between references.

Effects of the inclusion of sunflower hulls in the diet on growth performance and digestive tract traits of broilers and pullets fed a broiler diet from zero to 21 d of age. A comparative study

The effects of including 3% sunflower hulls (SFH) in the diet on growth performance, nutrient retention (TTAR), and gastrointestinal tract (GIT) traits were studied in chicks from zero to 21 d of age. Four treatments that resulted from the combination of 2 chicken lines (female broilers vs. brown pullets) and 2 levels of SFH (zero vs. 3%) were used. The control diet contained 2,980 kcal AMEn/kg, 1.25% digestible Lys, and 8.7% neutral detergent fiber. The experimental diet included 3% SFH at the expense (wt:wt) of the whole diet. Growth performance, TTAR of nutrients, and the AMEn of the diet were greater (P = 0.097 to P < 0.001) in broilers than in pullets. In absolute terms, all the organs of the GIT were heavier (P < 0.001) and the small intestine and cecum were longer (P < 0.001) in broilers than in pullets. At 21 d of age, however, the relative weight (% BW) of all the organs of the GIT (P < 0.001) and the relative length (cm/kg BW) of the small intestine and cecum (P < 0.01) were greater in pullets. Gizzard pH (P < 0.001), total short chain fatty acids concentration in the cecum (P = 0.098), and villus height (P < 0.001) and crypt depth (P < 0.05) of the ileum mucosa were higher in broilers. The inclusion of SFH increased (P < 0.05) the AMEn content of the diet but did not affect bird performance, moisture content of the excreta, or the concentration and profile of fatty acids in the cecum. Dietary SFH increased gizzard weight and reduced gizzard pH (P < 0.001) at both ages. In conclusion, broilers had better growth performance, nutrient retention, and ileum absorptive capacity than pullets. The inclusion of 3% SFH at the expense of the control diet did not have any negative effect on chick performance and, in fact, increased gizzard weight, reduced gizzard pH, and improved the energy content of the diet.

Performance, intestinal microflora, and amino acid digestibility altered by exogenous enzymes in broilers fed wheat- or sorghum-based diets.

The objective of the current study was to compare the effects of dietary enzymes and nutrient restriction on performance and bone mineralization in birds fed wheat- or sorghum-based diets. A total of 720 d-old male broiler chicks were randomly allocated to 8 treatments, with 6 replicates per treatment and 15 birds per replicate. Birds were reared in floor pens from 0 to 35 d. The study used a 2 × 4 factorial arrangement with 2 grains (sorghum or wheat) and 4 diets: positive control (no enzyme and ME, digestible Lys, Ca, and P sufficient, negative control (NC; no enzyme and reduced ME [-100 kcal/kg], digestible AA [-2%], Ca [-0.12 percentage points], and available P [-0.18 percentage points in the starter phase and -0.22 percentage points in the grower phase]), NC + nonstarch polysaccharide-degrading enzymes + phytase (500 phytase units [FTU]; NCCP), and NC + phytase (1,000 FTU; NCP). From 0 to 35 d, birds fed wheat-based diets had greater G:F (4.5%), BW gain (9.2%), breast meat yield (6.8%), and tibia ash (2.0%) compared with birds fed sorghum-based diets. Across grain types, the NCCP treatment improved BW gain ( < 0.001), feed intake ( < 0.001), G:F ( < 0.05), and livability ( < 0.001) compared with the NC treatment. Birds fed NCP had greater BW gain ( < 0.001), feed intake ( < 0.001), G:F ( < 0.001), and livability ( < 0.001) compared with birds fed NC. Birds fed the NCP diet had greater BW gain ( < 0.001), toe ash ( < 0.01), and tibia ash ( < 0.001) compared with birds fed the NCCP diet. There was a grain × diet interaction for feed intake ( < 0.01), BW gain ( < 0.001), tibia ash ( < 0.01), and tibia breaking strength ( < 0.05). The influence of enzymes was more pronounced in sorghum-based diets than in wheat-based diets. Birds fed wheat-based diets had greater ileal digestibility of His, Met, Val, Phe, Ile, Leu, Trp, Glu, Pro, Ala, Tyr, and Cys compared with those fed sorghum-based diets ( < 0.05). Across grain types, NCP had greater apparent ileal digestibility of Met, Lys, Ser, Pro, Gly, and Cys than NC ( < 0.05). The results suggest that wheat is superior to sorghum for broilers, as expected, but that enzyme supplementation has the capability to restore the compromised bird performance due to feeding sorghum. In addition, compared with nonstarch polysaccharide-degrading enzymes and phytase (500 FTU/kg feed) added in concert, phytase supplemented at 1,000 FTU/kg resulted in a further improvement of some of the performance and bone mineralization parameters in male broilers fed sorghum-based diets.

Performance, intestinal microflora, and amino acid digestibility altered by exogenous enzymes in broilers fed wheat- or sorghum-based diets

The objective of the current study was to compare the effects of dietary enzymes and nutrient restriction on performance and bone mineralization in birds fed wheat- or sorghum-based diets. A total of 720 d-old male broiler chicks were randomly allocated to 8 treatments, with 6 replicates per treatment and 15 birds per replicate. Birds were reared in floor pens from 0 to 35 d. The study used a 2 × 4 factorial arrangement with 2 grains (sorghum or wheat) and 4 diets: positive control (no enzyme and ME, digestible Lys, Ca, and P sufficient, negative control (NC; no enzyme and reduced ME [−100 kcal/kg], digestible AA [−2%], Ca [−0.12 percentage points], and available P [−0.18 percentage points in the starter phase and −0.22 percentage points in the grower phase]), NC + nonstarch polysaccharide–degrading enzymes + phytase (500 phytase units [FTU]; NCCP), and NC + phytase (1,000 FTU; NCP). From 0 to 35 d, birds fed wheat-based diets had greater G:F (4.5%), BW gain (9.2%), breast meat yield (6.8%), and tibia ash (2.0%) compared with birds fed sorghum-based diets. Across grain types, the NCCP treatment improved BW gain (P < 0.001), feed intake (P < 0.001), G:F (P < 0.05), and livability (P < 0.001) compared with the NC treatment. Birds fed NCP had greater BW gain (P < 0.001), feed intake (P < 0.001), G:F (P < 0.001), and livability (P < 0.001) compared with birds fed NC. Birds fed the NCP diet had greater BW gain (P < 0.001), toe ash (P < 0.01), and tibia ash (P < 0.001) compared with birds fed the NCCP diet. There was a grain × diet interaction for feed intake (P < 0.01), BW gain (P < 0.001), tibia ash (P < 0.01), and tibia breaking strength (P < 0.05). The influence of enzymes was more pronounced in sorghum-based diets than in wheat-based diets. Birds fed wheat-based diets had greater ileal digestibility of His, Met, Val, Phe, Ile, Leu, Trp, Glu, Pro, Ala, Tyr, and Cys compared with those fed sorghum-based diets (P < 0.05). Across grain types, NCP had greater apparent ileal digestibility of Met, Lys, Ser, Pro, Gly, and Cys than NC (P < 0.05). The results suggest that wheat is superior to sorghum for broilers, as expected, but that enzyme supplementation has the capability to restore the compromised bird performance due to feeding sorghum. In addition, compared with nonstarch polysaccharide–degrading enzymes and phytase (500 FTU/kg feed) added in concert, phytase supplemented at 1,000 FTU/kg resulted in a further improvement of some of the performance and bone mineralization parameters in male broilers fed sorghum-based diets.