Optimizing concentrations of dietary branched-chain amino acids (BCAA) can improve broiler chicken growth performance and carcass yields. A central composite design (CCD) study was conducted to understand the impact of dietary BCAA concentrations on Pectoralis major (PM) muscle protein expression and investigate the mechanisms behind how BCAA ratios affect broiler growth and muscle deposition. A total of 2,592 d-old Ross 344 × 708 male broilers were randomly placed in 144 floor pens. Each pen received 1 of 15 dietary treatments in the 23 CCD with 6 center points from 20 to 35 d of age, varying in digestible ratios of isoleucine:lysine (Ile:Lys; 52 to 75), valine:lysine (Val:Lys; 64 to 87), and leucine:lysine (Leu:Lys; 110 to 185). On d 35, 1 bird per pen was randomly selected for PM protein extraction and proteomic analysis via data independent acquisition protein sequencing with a timsTOF Pro 2 LC/MS/MS and Spectronaut 15 software. Branched-chain amino acid aminotransferase (BCAT1), adipocyte-type fatty acid-binding protein (FABP4), phosphoserine aminotransferase (PSAT1), O-N- acetylglucosamine transferase subunit p110 (OGT), and large neutral amino acids transporter small subunit 1 (SLC7A5) were identified, quantified, and analyzed as a CCD using the RSREG procedure of SAS ver. 9.4 with significance set at P ≤ 0.10. The surface response model for PSAT1 expression was significant (P = 0.0149; R2 = 0.24). However, the models for the other proteins were not significant (P ≥ 0.9592; R2 values ≤ 0.0336). A linear model effect (P = 0.0023) was observed for PSAT1 protein expression, while no quadratic (P ≥ 0.2085) or cross product (P ≥ 0.5886) regression effects were observed for any other proteins. A minimum stationary point was observed for BCAT1 protein. However, optimal values for the other proteins could not be obtained due to stationary saddle points. Still, the coefficients for the Ile:Lys cross-product ratio effect on PSAT1 (P = 0.0957) protein expression was significant.
Article Quarter: FY23 Q2
Influence of feed form and corn particle size on growth performance and meat quality of broiler chickens
The objective of this trial was to evaluate the effect of coarse corn inclusion and feed form on growth performance, meat quality, litter moisture and organ weights of broilers raised to 35 days. A total of 616 one-day- old mixed-sex Ross 308 broiler chicks were randomly distributed in 28 pens and assigned to 4 treatments with 7 replicates per treatment and 22 birds per replicate. Diets were corn-SBM-based and contained 2 levels of coarse corn (0 and 5% starter/10% grower) and were fed either as mash or crumble (starter)/pellet (grower)). The fine corn particle size was 924 μm and the coarse corn particle size was 1241 μm. Birds were fed starter (1-14 d) and grower (15-35 d). Body weight, feed intake, mortality adjusted FCR, and litter moisture were measured weekly. Processing, parts yield, and organ weights were determined on d 35. Data were analyzed as 2 × 2 factorial arrangement of (coarse corn inclusion x feed form) using GLM procedure of SAS to evaluate main effects and interactions. Tukey’s HSD test was used to separate means and statistical significance considered at P < 0.05. The inclusion of coarse corn during starter and grower period and pellets produced higher BWG (P<0.05) at 35 days compared to fine corn and mash, respectively. Feeding pellets improved (P<0.01) FCR compared to mash diets (1.79 versus 1.63). Furthermore, broilers fed pelleted diets had higher (P<0.001) breast fillet compared to broilers fed mash diets (511 versus 435 g). Pelleted diets increased litter moisture at 35 d (P<0.05) compared to mash diets (40.2 vs 47.1%). Organ development (gizzard, proventriculus, duodenum jejunum, and ileum weights) was not influenced by treatments.
Ileal digestible, metabolizable, and nitrogen corrected metabolizable energy of soybean meal with inclusions of exogenous carbohydrases for growing broiler chickens
Enspira (ESP) and Enspira+ (ESP+) are precision engineered blends of exogenous enzymes designed to degrade non-starch polysaccharides in common diet formulations. An experiment was conducted to determine the responses of the ileal digestible energy (IDE), apparent metabolizable energy (AME), and N corrected AME (AMEn) of soybean meal (SBM) to ESP or ESP+ inclusion. Cobb-500 male broiler chickens were obtained and fed a corn-SBM-based starter diet. At 20 d of age birds were individually weighed and 288 birds were allotted to 6 dietary treatments (6 birds/cage) in a randomized complete block design. Three corn-canola meal-based reference diets were created. One contained no enzymes and each of the other 2 contained 125 mg/kg of either ESP or ESP+. Then, 3 test diets were created by adding 150 g/kg SBM to each of the reference diets at the proportional expense of all energy contributing ingredients, producing 3 pairs of diets (control, ESP, ESP+). Experimental diets were fed from d 20 to 25 and excreta collected from d 23 to 25. At d 25, birds were euthanized and digesta collected from the terminal two-thirds of the ileum. Feed, digesta, and excreta samples were dried and analyzed for dry matter (DM), N, Ti, and gross energy (GE) content. Energy values were calculated using a difference method. Data were subjected to an ANOVA and contrasts were used to compare the effect of the enzymes with and with SBM. The addition of 150 g/kg SBM reduced the metabolizability of GE (P < 0.05) and N (P < 0.01) and produced lower IDE, AME, and AMEn of the test diets (P < 0.05). Inclusion of ESP or ESP+ had no effects on the on the metabolizability of DM or GE for either the reference or test diets, although both enzyme blends produce numerical increases in the GE and DM metabolizability of the test diets. Inclusion of ESP elevated (P < 0.05) the estimated AME of SBM obtained from this study (405 kcal/kg DM) and ESP+ inclusion tended (P < 0.10) to elevate the AME of SBM (304 kcal/kg DM). However, there were no significant differences observed for the IDE or AMEn of SBM.
Methionine supplementation and immune function in broilers experiencing an acute inflammatory challenge
Methionine is the first-limiting amino acid for broilers and plays a critical role in immune function. This study investigated the impact of graded supplemental levels of methionine in broilers undergoing a lipopolysaccharide (LPS) challenge. A total of 336 male broilers (Ross 308) were housed in batteries and allotted to 1 of 6 dietary treatments, with 7 replicates of 8 birds per replicate. Diets were provided in a 2-phase feeding program with a common starter diet and experimental grower diets provided d 0-10 and 10-28, respectively. Grower diets included a basal diet (0.136% digestible Met) supplemented with 0.360% L-Cys (0%DLM) and five other supplemented diets with graded levels of DL-Met (0.072%DLM- 0.360%DLM, with 0.072%DLM increments). To ensure the only limiting amino acid would be Met, other amino acids were included at approximately 15% over the AMINOChick 3.0 recommendations. All diets were provided ad libitum throughout the study. On study d 25 [0 hours post- stimulation (HPS)], all birds were challenged intraperitoneally with LPS derived from E. coli (O127:B8) at 2.0 mg/kg BW with 1 bird per pen was euthanized for sample collection at 5 HPS. Body weight gain during the grower phase was lowest (170 g, P < 0.01) in 0%DLM compared with 0.216%DLM or higher (1,067 g, 1,103 g and 1,112 g, respectively). Birds receiving 0%DLM had the least efficient feed conversion ratio (3.56 g/g, P < 0.01) compared with treatments ≥ 0.216%DLM (1.5). The treatments ≥ 0.216%DLM had, on average, 1.07 percentage points lower (P < 0.01) relative liver weights (%BW) at 5 HPS compared with 0%DLM (4.35%). Plasma concentrations of the acute phase protein, α-1-acid glycoprotein (AGP), were elevated (180. 3 μg/mL, P < 0.01) in 0%DLM compared with 0.144%DLM (88.3 μg/mL) and 0.288%DLM (76.5 μg/mL) treatments; however, there were no differences in interleukin-6 plasma concentrations.
In vivo amino acid digestibility is inversely correlated to the trypsin and chymotrypsin inhibitor contents of commercial solvent extracted soybean meal
The objective of this study was to determine the relationship between in vivo amino acid digestibility and protease inhibitors in commercial soybean meal (CSBM). A total of 12 CSBM samples were analyzed for: (1) trypsin inhibitor activity (TIA) utilizing the new official AOCS method (Ba 12a-2020). (2) chymotrypsin inhibitor activity (CIA) by the latest optimized method of Liu (2022. J. Food Sci. https://doi.org//10.1111/1750- 3841.16141), and (3) in vivo amino acid (AA) digestibility determined utilizing the precision-fed cecectomized rooster bioassay as described by Corray et al. (2018. Poult. Sci. 97:3987-3991). Linear and quadratic regressions of digestible AA coefficients on TIA and the summation of TIA and CIA (TIA+CIA) were conducted using PROC GLM in SAS (2013). The TIA ranged from 3.53 to 12.82 units inhibited (UI)/mg of CSBM. The TIA+CIA ranged from 8.74 to 23.40 UI/mg of CSBM. All 17 determined digestible AA coefficients for each of the 12 CSBM samples were negatively correlated with TIA and TIA+CIA values. For TIA, linear regression R-square values ranged from 0.48 (r= -0.69) for digestible lysine to 0.72 (r= -0.85) for digestible serine (P<0.05). There was no significant quadratic effect of TIA vs. digestible AA for all AA. For TIA+CIA, linear regression R-square values ranged from 0.41 (r= -0.64) for digestible cysteine to 0.77 (r= -0.88) for digestible serine (P<0.05); there was no significant quadratic effect of TIA+CIA vs. digestible AA for all AA.
Growth performance response in tom turkeys fed conventional diet supplemented with monoglycerides of short and medium chain fatty acids
This study aimed to investigate the effects of butyric, caprylic, and capric monoglycerides (MG) on the growth performance of male turkeys when supplemented at 0, 300, 600, 900, 1200, 1500 and 1800 g/MT feed. A total of 840 male Hybrid Converters turkeys (15 birds × 8 pens/treatment) were randomly allotted to the 7 dietary treatments (Trt) in a randomized complete block design. A corn-soybean meal based diet with fixed minimal amount of meat meal and DDGS per phase was formulated and fed in 6 phases (d0-21, d21-42, d42-63, d63-84, d84-105, and d105-119). All diets were formulated to meet the breeder’s recommendations and to simulate a standard US turkey diet. Feed intake (FI) and body weight (BW) data were collected for each phase during the 17-weeks study. Body weight gain (BWG) and feed conversion rate adjust for chick days (FCRa) were calculated. The experimental unit was the pen and data were analyzed using mixed model of JMP®. Quadratic polynomial (QP) model was used to fit the titrated levels for both Trt LSMeans and pen means. The level which maximized BW or minimized FCRa from the QP model are reported. Only the responses with significant Goodness of fit (P<0.05) were reported, which were the supplementation of MG at 0 – 1800 g/MT during 0-3 weeks period. The results suggested that to maximize BWG from 0-3 weeks, it would require 624 g/MT using Trt LSMeans and 644 g/MT using pen means while FCRa was minimized at 482 g/MT using Trt LSMeans and 478 g/MT using pen means. Although, One-Way ANOVA showed no significant differences among 7 treatments for BWG and FCRa for any phase, consistent numerical improvement in BWG and coefficient of Variation (CV) were observed for all phases in comparison to the diets with no MG. The improvement in BWG at 300 g/MT ranged from 1.42 – 4.93 %, while the CV improvement at the same level ranged from 18 – 70 %.
Productive energy (Ark NE), apparent metabolizable energy (AMEn) and net energy (NE) values for diets and ingredients for 5-56d broiler grow-out studies
Arkansas net energy (Ark NE) is a productive energy system based on actual dietary energy utilized for gain and maintenance. A total of 48 diets with varying levels of total digestible amino acids (TDAA), digestible starch (DSTAR), digestible fat (DFAT), and NSP were utilized in 5-56d broiler studies to determine the performance and energy value of diets and ingredients using DEXA and indirect calorimetry system. Data were subjected to a one-way ANOVA and Tukey’s HSD to compare separate treatment means with significance set at 0.05 using JMP pro16. Multiple linear regression models were computed to generate prediction equations for the energy values of ingredients. Treatment diets significantly impacted broil- er performance, ADG, and FCR. FCR provided a much stronger negative relationship to Ark NE (R2 = 0.52) compared to AMEn (R2 = 0.16) and classic NE (R2=0.17). The TDAA, DFAT, and DSTAR were positively re- lated to Ark NE (P<0.05), while total NSPs negatively affected Ark NE for 56d broiler performance. Each percentage increase of TDAA, DFAT and DSTAR increased the predicted Ark NE value by 74, 58, and 32 kcal/kg, respectively, while increase of NSP decreased the predicted Ark NE value by 18 kcal/kg in the multiple linear regression model. Conversely, AMEn and classic NE systems were strongly influenced by DFAT compared to TDAA and DSTAR in the same diets. The average energy efficiency (EE) of Ark NE compared to AMEn (Ark NE/AMEn) was 85.48% and the EE of classic NE compared to AMEn was 75.49% for the same diet. The predicted Ark NE values of SBM, corn, and corn oil were 3340, 2511, and 5,728 kcal/kg for 56 d broiler performance, respectively.
Body composition and fasting heat production of modern broilers and their relationship with dietary productive energy (Arkansas Net Energy)
The heat production (HP) of broilers has been shown to increase through the years associated with higher breast meat yield, supporting the use of an energy system that better accounts for HP differences caused by changes in genetics, body composition (BC), nutrition, and environmental temperature. This study aimed to determine the influence of BC on fasting HP (FHP) and the sensitivity of models based on metabolic body weight (MBW) alone or including BC to determine the maintenance net energy of broilers. Four experiments (E1 to E4) were conducted to determine the influence of BC on FHP and develop prediction models, and two experiments (E5, E6) to validate them. In E1 to E4, a total of 2400 Cobb 500 broilers distributed into 96 floor pens, were fed three dietary treatments to induce BC differences. The FHP (indirect calorimetry) and body protein-to-fat ratio (PFR; Dual-Energy X-Ray Absorptiometry) were determined from 1 to 56 d. The metabolic allometric coefficient was estimated using non-linear modeling and multiple linear models (response variable: FHP) were adjusted to the data using JMP Pro 16.0.0. In E5, broilers fed one of six dietary treatments were tested for FHP and BC three times within 1-42 d. In E6, broilers of two genetic lines distributed into 54 pens (45 birds each) and fed three dietary treatments were also tested twice within 1-42 d. The allometric coefficient was determined to be not different from 0.75 (P >0.05). Four models developed (R2 >0.98), considering body weight, PFR, and age, were validated (R2 >0.92; error <3%). Results showed that the leaner the bird, the higher the FHP (P <0.0001). Models based on MBW alone underestimate (+10% dif.) the FHP of lean birds being the estimations unreliable (regression assumptions not met), but including BC allows detecting +18% FHP differences. FHP and body energy retention (ER), expressed per unit of feed intake, account for productive energy (Arkansas Net Energy; Ark NE).
Variability in energy value, nutrient and trypsin inhibitor content of extruded full-fat soybeans due to genetics and agronomic conditions
Dry extruded full-fat soybean meal (FF) is used as a feed ingredient for poultry. Meal quality can vary due to processing, soybean variety, and production conditions. This study evaluated the proximate and predicted energy values, and trypsin inhibitor activity (TIA) of FF affected by soy genetics, location, and seasons in a factorial experiment. Two soybean varieties (SV), AG56X8 (X) and S62XT09 (Y) were planted in three North Carolina counties (A, B, C location) at two planting dates: double crop and full season. 12 treatments resulted from the 2x3x2 factorial arrangement. Soybeans were harvested as they reached maturity, dried to 8-8.5%, and dry-extruded between 148-154.5oC in a single screw extruder, Insta-Pro 2000R. Five samples were collected from raw soybeans and FF, ground in Retsch mill to 0.5 mm, and scanned in triplicate in NIRS. The spectra were analyzed using AminoNIR (EVONIK) calibration curves. The data was standardized to DM basis and analyzed using a three-way ANOVA with mean separation using Tukey’s test. Three-way interaction effects (P<0.001) were observed on nutrient composition. Soybean grown in full season with variety X in locations A and B produced FF with the highest crude protein (CP), compared with the double crop with the same SV in location C, which contained the lowest CP and highest ether extract (EE). However, there was a negative correlation between CP and EE. Higher crude fiber (CF) was observed in both SV in location C regardless of planting date and in SV X in the double crop at location C had the highest value. Both SVs had the highest AMEn in location B for the double crop. In this location, SV X had higher AMEn values in the full season. The AMEn was positively correlated to EE content. The SV X in locations A and B planted in full season contained the lowest TIA. Both SV in location C planted in double crop had the highest TIA values. The correlation (P<0.001) between raw soybean and FF in CP, EE, CF, and TIA were 0.86, 0.66, 0.65, and 0.58, respectively. The TIA in FF can be predicted (P<0.001) from its content in the raw soybeans (Y= -20.39+1.15X; R2 =0.34).
The influence of dietary glycine concentration in reduced crude protein diets with different Met to Cys ratios fed to broilers
Two experiments (EXP) investigated broiler growth (0-21 d) and tissue glutathione (EXP 2) when fed reduced CP (RCP) diets with different dietary Gly levels and Met:Cys ratios. Ross 708 male off-sex chicks reared in floor pens (12 birds/pen) were used in EXP 1 (1,716 chicks) and 2 (1,344 chicks). EXP 1 included 13 diets: a control (CTL) diet or RCP diets (~3.6 unit CP reduction) formulated to either a high (74:26) or low (60:40) Met:Cys ratio and 1.75, 2.01, 2.27, 2.53, 2.79 or 3.05% total Gly+Ser levels (tGly+Ser). EXP 2 included 6 diets: a CTL diet or RCP diets (~2.6 unit CP reduction) formulated to have either a high (72:28) or low (55:45) Met:Cys ratio and 1.60, 2.08 or 2.56% tGly+Ser. An additional factor in EXP 2 was Eimeria vaccination status [without (UNVAC) or with (VAC)]. Both EXP used one feeding phase. Treatments were rep- licated in 11 (EXP 1) or 16 (EXP 2) pens. Body weight gain (BWG), feed intake (FI), and FCR were evaluated, and in EXP 2, liver, blood and jejunum mucosa from 2 birds/pen of 70 pens were sampled for glutathione analysis. Data from EXP 1 were analyzed by a 2-way ANOVA with linear and quadratic contrasts across Gly levels, while EXP 2 data used a 2- and 3-way ANOVA (P≤0.05). In EXP 1, birds fed the RCP diet had lower (P<0.05) 0-21 d BWG and FI than CTL-fed birds, and increasing tGly+Ser linearly reduced (P<0.001) BWG and FI, but did not affect FCR. In EXP 2, 0-21 d bird BWG, FI and FCR were negatively affected (P<0.001) by VAC, and increasing tGly+Ser improved (P≤0.043) BWG, FI and FCR independently of VAC status. Birds fed RCP diet had inferior performance (P<0.05) than CTL-fed birds. Increasing tGly+Ser lowered FCR of UNVAC, but did not benefit the FCR of VAC birds. The Met:Cys ratio did not interact (P>0.05) with Gly levels or affect bird performance in either EXP. In EXP 2, liver glutathione levels were increased (P<0.05) by VAC, and VAC×Met:Cys interactions were observed for mucosa glutathione.
