Pork is one of the most consumed animal-derived protein sources around the world, but less than 45% of dietary nitrogen (N) is converted into edible lean meat. This inefficiency contributes to the 80% of human-induced N emissions that have resulted in exceeding the planetary boundaries for N. Reducing this inefficiency requires using a multifaceted approach. Swine genetic selection programs have improved the rate of lean growth in recent decades, but further improvements may be difficult because of lack of genetic variation within the global pig population. Breeding programs to increase litter size have led to intrauterine growth restriction and an increased proportion of low-birth-weight piglets which do not utilize dietary protein as efficiently as normal birth weight pigs. Intact males have greater lean growth rate and N efficiency than castrates and gilts, and the use of immunocastration technology has been implemented in some countries to capture this benefit while minimizing boar taint in pig meat. Use of other metabolic modifiers including porcine somatotropin and ractopamine, alone or in combination with immunocastration, can further enhance lean growth and dietary N efficiency, but a general lack of consumer acceptance and potential food safety concerns have led to regulatory restrictions in many countries.
Article Quarter: FY23 Q4
Towards a better understanding of anti-nutritional factors, reactive lysine, KOH protein solubility, and rooster amino acid digestibility in commercial soybean meals
The two primary objectives were 1) to determine trypsin inhibitor (TI) and chymotrypsin inhibitor (CI) levels using two different methods and 2) to determine near infrared spectroscopy reactive Lys (NIR RL) (Evonik), KOH protein solubility (KOHPS), and in vivo rooster amino acid (AA) digestibility in commercial samples of solvent extracted dehulled soybean meal (SBM) and extrusion expeller mechanically processed SBM. A total of 99 samples of SBM were obtained; 86 solvent and 13 mechanical. After sample evaluation using NIR TI and SOY CHEK (LSB Products, Manhattan, KS), 54 SBM (44 solvent and 10 mechanical) were selected for further analyses including trypsin units of inhibition (TUI/g) and chymotrypsin units of inhibition (CUI/g) using the new AOAC method (Liu et al., 2021), and trypsin inhibition units (TIU/g) and chymotrypsin inhibition units (CIU/g) using a new, fast, and cost-effective procedure (Kim and Krishnan, 2023). In addition, 36 of those SBM were evaluated for in vivo AA digestibility using 4 to 6 individually caged cecectomized roosters per sample. Roosters were fasted for 26 h prior to crop intubation with 25 g of SBM and excreta were quantitatively collected for 48 h. Data were analyzed using regression analyses to determine linear and quadratic relationships among variables. The probability level for statistical analyses was P < 0.05. No differences in NIR RL were observed between solvent and mechanical SBM. Values for TUI/g ranged from 1.1 to 17.2 among SBM, and mechanical SBM had a higher mean TUI/g of 13 compared with a mean of 7 in solvent SBM. The NIR TI was positively correlated (P < 0.05) with TUI (R2 = 0.56). Mean TUI values were higher than TIU values primarily because many SBM with low TUI levels had 0 TIU/g. Rooster Lys, Met, and Cys digestibility ranged from 70 to 96, 79 to 91, and 69 to 84% among SBM, respectively. For the regression analyses, NIR RL exhibited a quadratic relationship with rooster Lys and Arg digestibility (R2 = 0.40 to 0.42). Analyzed KOHPS was positively correlated with NIR RL and rooster Lys and Arg digestibility (R2=0.47 to 0.73). Maximum rooster AA digestibility was predicted to occur at a lower TUI level for solvent SBM than for mechanical SBM. Results for CUI, TIU, and CIU were similar to those for TUI and there was generally no advantage of measuring CUI or CIU in addition to TUI.
Assessment of soybean genotype amino acid and oil selection improvements on broiler performance
This experiment aimed to determine the feeding value of soybean meal (SBM) produced from varieties of soybeans bred for increased amino acid content (SBAA) and improved fatty acid profile (SBO), compared to a conventional soybean variety in Cobb 500 female broilers. Analyzed NIR values for whole soybeans reached statistical significance for nearly every analyzed value (P<0.05). Overall, SBAA and SBO soybeans contained higher amino acid content and lower oligosaccharide content compared to the conventional soybean variety, in addition to improved fatty acid profile. Prior to the experimental period all birds were reared on common feeds. Despite having significantly different values for nutritional components as whole soybeans, once processed into soybean meal, proximate and AA analysis values were very similar for conventional and experimental soybean meals. Therefore, diets were formulated based on analysis values from the conventional SBM and inclusion amount of experimental SBM was set to 20% in all diets. Diet 1 contained SBM from conventional soybeans whereas Diets 2 and Diet 3 contained SBM from experimental soybean lines, SBAA and SBO, respectively. Diets were fed to 288 female broilers placed in eight replicate pens of twelve birds each and live performance was assessed from d 28 to 42. At d 42, six birds from each pen were randomly selected and processed for evaluation of carcass traits and incidence of woody breast. Carcass parameters measured include live weight as well as fat, breast, tender, wing, and leg chilled yields. All performance data were analyzed using a One-way ANOVA using JMP software with diet as the fixed effect and block as a random effect with pen as the experimental unit. Statistical significance was considered at P ≤ 0.05. No significant responses were observed for any live performance, carcass, or woody breast measurements.
Determination of TMEn, standardized amino acid digestibility, and phosphorus digestibility in soybean expellers produced from a new variety of soybeans fed to chickens
The objective of this study was to test the hypothesis that nitrogen-corrected true metabolizable energy (TMEn), standardized amino acid (AA) digestibility, and apparent ileal P digestibility are not different in a soybean expeller (SBE) produced from a new variety of Photoseed soybeans compared with SBE produced from conventional soybeans. The Photoseed soybeans have been developed to capture more carbon and sunlight, leading to an ingredient that has reduced environmental footprint from crop production. The two SBE contained approximately 46.3 % protein on a DM basis. In Experiments 1 and 2, two precision-fed rooster assays were conducted to determine TMEn and standardized AA digestibility in conventional and Photoseed SBE using conventional and cecectomized roosters, respectively. For each experiment, six replicate White Leghorn roosters were fasted for 26 h and then tube fed 25 g of each SBE, and excreta samples were collected for 48 h post-feeding. Data were analyzed as a one-way ANOVA for a completely randomized design. Differences between treatments were considered significant at P < 0.05. Results from Experiment 1 yielded TMEn values of 3.162 and 3.261 kcal/g DM for the conventional SBE and Photoseed SBE, respectively, with the value being greater (P < 0.05) for Photoseed SBE. Results from Experiment 2 showed standardized digestibility of most AA of approximately 90%, and there was no difference between the two SBE. However, Photoseed SBE had greater (P < 0.05) concentrations of digestible Arg, Lys, Phe, Trp, and Val compared with conventional SBE. In Experiment 3, an ad-libitum-fed broiler chicken assay was conducted to determine apparent ileal P digestibility in conventional and Photoseed SBE. Eighty commercial Ross 308 male chicks were fed a standard corn- SBM diet from 0 to 16 d of age and birds were then fed diets containing one of the SBE as the only source of P from d 17 to 21. The 2 experimental diets had a Total Ca:Total P ratio of 1.4:1 and TiO2 was used as a digesta marker. There were 5 chicks per pen and 8 replicate pens per treatment and the pen was the experimental unit. On d 21, chicks were euthanized and ileal digesta were collected. Data were analyzed as in Experiments 1 and 2. Results indicated values for apparent ileal P digestibility of 46.8% and 40.6% for conventional SBE and Photoseed SBE, respectively, and these values were not different. In summary, TMEn was greater in Photoseed SBE compared with conventional SBE, but digestibility of AA and P was not different although Photoseed SBE had greater concentrations of some indispensable AA compared with conventional SBE.
Comparison of the nutritional and economic value of soybean meal from five origins in poultry and swine feed formulation
Soybean meal (SBM) is the primary protein ingredient in poultry and swine diets and generally accounts for most of the feed cost. However, its quality and nutritional value vary due to regional crop, processing, and storage conditions which can impact animal performance and feed cost. This study aimed to evaluate the nutrient and energy composition of North Carolina (NC) SBM and compare the differential feed cost to SBM of other origins. A total of 35 and 45 samples of SBM produced in NC in 2020 and 2021 were collected and analyzed by NIRS. Proximate composition, energy, and quality parameters were determined using AminoNIR (Evonik) calibration curves. The nutrient and energy values of SBM produced in the Eastern and Western regions in the USA, Brazil, and Argentina were obtained from the AminoNIR (Evonik) 2020 and 2021 reports. Feed was formulated in a least-cost software (Concept 5.0®) for diverse feeding phases of broilers, layers, and swine. For each one of these diets, SBM of these five origins was included at different levels to achieve the lowest feed cost. Broiler starter (35-36% SBM inclusion), grower (33-35%), and finisher (29-31%) diets were formulated following Ross 708 (2019) nutrient specifications. Brown and white layer diets for phases 1 (26-28% SBM inclusion) and 2 (21-22%) were formulated following the Hy-Line (2021) nutrient guidelines. For swine, growing boars, and gilts, phases 2 (20-25% SBM inclusion), and 3 (14-16%), were formulated using PIC (2021) recommendations. Nutrient and energy data were analyzed in a one-way ANOVA and means separated using Tukey’s HSD test. Significant differences between SBM of different origins were observed for all parameters evaluated (P < 0.001). The NC SBM had the highest ME values for poultry (between 29-218 and 57-167 kcal/kg more for 2020 and 2021, respectively) among all other sources. SBM produced in NC also had the highest crude protein content in both years (47.53% and 47.84%). NC SBM had slightly lower amino acid (AA) content than Brazilian SBM but higher than Argentinian and Western US SBM and very similar to Eastern US SBM (P < 0.001). For both years, diets formulated with NC SBM were cheaper than using all other sources, between 2.38-31.08 US$/ton for broiler diets, 0.88-22.96 US$/ton for laying hen diets, and 2.05-14.98 US$/ton for swine diets, except for Brazilian SBM in the broiler starter.
Assessment of net energy and amino acid formulation in Cobb 500 broilers for a 31-41d finisher period
This experiment was focused on determining the potential outcomes of feeding varying levels of CP and net energy (NE) on live performance and carcass traits during the finisher phase (31–41d) in Cobb 500 broilers. The NE formulation in poultry may provide better accuracy in terms of energy values of ingredients. In NE equations, heat increment is utilized, and thus positive results may be achieved, such as better energy efficiency and utilization, in addition to avoiding dietary energy misuse. Amino acid formulations at proper levels are known in poultry for improving muscle growth, performance, and reducing environmental damage. Cobb 500 fast feathered broilers(2,304) were vent-sexed and randomly allocate to a tunnel- ventilated house containing 96 pens (6 x 8 feet). Each pen had 24 birds (12 per sex) which were fed to 12 different experimental diets. Primary breeder recommendations for management of lighting, ventilation, and temperature, were strictly followed, while water and feed were provided ad libitum. A 3×4 factorial arrangement was designed and the 12 experimental diets (8 replications each) were: 1) 2,250 kcal/kg NE, 16% CP; 2) 2,300 kcal/kg NE, 16% CP; 3) 2,350 kcal/kg, 16% CP; 4) 2,400 kcal/kg, 16% CP; 5) 2,250 kcal/kg NE, 18% CP; 6) 2,300 kcal/kg, 18% CP; 7) 2,350 kcal/kg, 18% CP; 8) 2,400 kcal/kg, 18% CP; 9) 2,250 kcal/kg, 20% CP; 10) 2,300 kcal/kg, 20% CP; 11) 2,350 kcal/kg, 20% CP; and 12) 2,400 kcal/kg, 20% CP. All data were analyzed using a two-way ANOVA and a mixed model design, and the dietary treatments were set to pens in a randomized complete block design, whereas the location of the pens was the blocking factor. Pen was used as the experimental unit. No CP x NE interactions (P > 0.05) occurred on any live performance parameter (32–41d) or carcass trait (42d). Furthermore, increasing the dietary energy above 2,250 kcal/kg NE did not ameliorate carcass characteristics. However, birds fed increased NE obtained improved feed conversion ratio (FCR), and reduced feed intake (FI) (P<0.05). Broilers fed increased CP had improved FCR, and breast meat yield; additionally, they had decreased FI and abdominal fat deposition (P<0.05).
Ileal digestibility of crude protein and amino acids of soybean meals of different origins in broilers
The influence of the origin of the soybeans on the apparent (AID) and standardized (SID) ileal digestibility of CP and amino acids (AA) of 27 commercial soybean meals (SBM) from Argentina (ARG), Brazil (BRA), and USA was studied in broilers at 21 d of age. The samples (n = 9 per origin) were collected at the arrival of the vessels to Europe or at the crushing plants and were analyzed for main components (CP, AA, ether extract, carbohydrates, and minerals), protein quality indicators (urease activity, protein dispersibility index, KOH solubility, and trypsin inhibitor activity), and reactive Lys, using the homoarginine and furosine procedures. Broilers received a commercial corn-SBM diet in crumble form from hatch to 16 d of age and then, their corresponding experimental diets for 5 d. The experimental diets resulted from the combination of 53% of a N-free diet (dextrose, soybean oil, lignocellulose, minerals, and vitamins) and 47% of the corresponding SBM tested, as the unique source of N. Each of the 27 experimental diets was replicated 6 times and the experimental unit was a cage with 8 broilers. Chemical analyses and in vivo data were analyzed as a completely randomized design using the MIXED procedure of SAS, with SBM origin as main effect. For the in vivo data, SBM sample within each origin, was used as a nested effect. On 88% DM basis, CP (N × 6.25) was higher for the BRA meals than for the ARG and USA meals (47.4, 46.3, and 46.5%; P < 0.05). Per unit of protein, however, the contents in Lys, TSAA, and the sum of 5 key AA (Lys, Met, Cys, Thr, and Trp) were higher for the USA meals than for the South American meals (P < 0.05). At 21 d of age, the SID of the protein (92.2 vs. 91.2 and 91.6%; P < 0.05) and of the sum of 5 key AA (91.7, 90.5, and 91.3%; P < 0.05) were higher for the USA meals than for the BRA and ARG meals. When each AA was evaluated individually, the SID of Arg (94.9 vs. 93.8 and 94.1%) and Lys (93.8 vs. 92.4 and 93.3%) were higher (P < 0.05) for the USA meals than for the BRA and ARG meals. Similar differences to those reported for the SID were found for the AID values. Based on the coefficient of variation (%), the SID and AID values of the SBM samples for all key AA except Trp, were less variable for the USA than for the South American meals.
Effect of high leucine diets supplemented with arginine and valine on growth performance and gut health in broilers challenged with Eimeria maxima
The objective of this study was to investigate the effects of supplementation of arginine and valine on growth performance and gut health in broilers challenged with E. maxima and fed excess leucine diets. A total of 832 fourteen- day-old Cobb 500 male broilers were randomly allocated to a 2×2×4 factorial arrangement with 4 replicate cages of 12 birds per cage. The main factors were two dose of E.maxima (EM) either challenged (CC) or non-challenged (NC), two Leu levels of either normal Leu (NL) or high Leu (HL) and amino acid (non-supplemented, 0.5% supplementation of Arg; ARG, 0.5% supplementation of Val; VAL, and ARG & VAL combination group; COM). All data for each response were statistically analyzed three-way ANOVA with Tukey’s post-hoc test. EM challenge decreased (P<0.05) growth performance, lean mass and percentage, and crypt depth in the jejunum, gene expression related to gut health such as mucin 2 (MUC2) and occluding (OCLDN), antioxidant capacity such as superoxide dismutase 1 (SOD1), catalase (CAT) and glutathione peroxidase 1 (GPX1), and protein synthesis such as mammalian target of rapamycin (mTOR) and eukaryotic translation initiation factor 4E binding protein 1 (4EBP1), while increasing (P<0.05) lesion score, FITC-d level in serum, and cytokine such as tumor necrosis factor-alpha (TNF-α), interleukin-2 (IL-2) and interleukin-10 (IL-10) compared to non-challenged groups. HL diets decreased (P<0.05) growth performance and increased (P<0.05) gene expression of mTOR compared to NL diets. Supplementation of Arg and Val (COM) improved (P<0.05) growth performance, intestinal morphology, gene expression related to gut health such as MUC2, zonula occludens 1 (ZO1), antioxidant capacity such as SOD1, and protein synthesis such as mTOR and 4EBP1, and thus mitigated (P<0.05) jejunal lesion score, release of oocyst shedding, and gene expression of TNF-α compared to non-supplemented groups. Especially, when broilers fed diets with Arg and Val, poor growth performance lean mass and crypt depth caused by E.maxima and high leucine were mitigated (P>0.05).
Evaluating the potential of branched-chain amino acid as proteinogenic amino acids compared to lysine in broiler chickens fed reduced-protein diets
The objective of the study was to examine the impact of increased branched-chain amino acids (BCAA) blends to lysine ratio on growth performance, nutrient utilization, caecal short-chain fatty acid (SCFA), and protein and fat accretion in the pectoralis major muscle in broiler chickens fed a reduced-protein diet. A total of 270 Cobb 500 male broiler chicks were allocated into 18-floor pens, with 15 birds per pen on d 0. All birds received the same starter diets (220g/kg crude protein and 3,000 kcal/kg AME) during the first 8d. Thereafter, three experimental diets (D) were provided for the grower (8-28d) phase, namely D1, which was an adequate-protein diet (190g/kg crude protein) with the recommended Lys to BCAA ratio (100:294), D2 was a reduced protein diet (170g/kg crude protein) with recommended Lys to BCAA ratio (100:294), whereas D3 had the same protein content as D2 but with a 10-point decrease in Lys and a proportionate increase in BCAA, that is Lys: BCAA of 90:304. The ratios of individual AA in the BCAA group were kept constant in all the diets. Birds and feed were weighed on d8 and 28. Ileal digesta and ceca content were collected from 5 birds per pen on d21 for AA digestibility and SCFA analysis, respectively. On d28, the pectoralis major was collected from one bird per cage to analyze protein and fat composition. The birds fed D3 had lower (P < 0.05) weight gain and greater FCR than the other diets, whereas birds fed D1 and D2 had similar weight gain and FCR values. The birds receiving D1 and D2 had greater (P < 0.05) AA digestibility values than D3. However, digestibility was similar for D1 and D3 except for Asp, His, Lys, Pro, and Tyr, which were lower (P < 0.05) for D3 than for D1. There was no treatment effect on the digestibility of Arg, Met, Thr, and Gly. In addition, the birds fed D1 had (P<0.05) greater N digestibility compared to those receiving D2 or D3. The cecal content of propionate and total SCFA tended (P < 0.10) to be lower in birds receiving D3, but there were no treatment effects on the cecal content of the other SCFA. The birds receiving D3 had (P<0.05) greater fat and dry matter, and by contrast, lower protein content in the breast muscle than D1.
Optimization of dietary valine to lysine ratios in response to varying leucine to lysine ratios in male broilers from 20 to 34 days of age
A study was conducted to determine the optimization ratio of valine to lysine dependent on dietary leucine to lysine rations with a fixed isoleucine to lysine ratio on live performance and carcass traits in Ross 344 × 708 male broilers from 20 to 34 days of age. A total of 1,080 d-old male chicks were randomly placed into 72-floor pens according to a 2n=2 full factorial in central composite design (CCD) with 12 runs (8 treatments + 4 central points) and 6 replicates per run. A common feeding program was adopted until 20 days of age. Subsequently, each pen received 1 of 9 dietary treatments from 20 to 34 days of age varying in digestible ratios of Val:Lys (70 to 86) and Leu:Lys (90 to 192) which were calculated according to their corresponded code matrix values (-, -1, 0, +1, +). Digestible Ile:Lys ratio was fixed across all treatments at 68. Birds and feed were weighed at 20 and 34 d of age to determine body weight gain (BWG), feed intake, and feed conversion ratio (FCR). At 35 d of age, all birds were processed to determine carcass characteristics. Data were analyzed using JMP v.15 by adopting the response surface macro option. Body weight gain (1547 g; P = 0.15) for the period was optimized at a Val:Lys ratio of 85 and a Leu:Lys ratio of 108. Feed conversion ratio (1.498; P = 0.003) from 20 to 34 d of age was optimized at a Val:Lys ratio of 81 and a Leu:Lys ratio of 116. Poorer BWG and FCR were observed as Leu:Lys ratio increased although increasing Val:Lys ratios partly alleviated the poor performance. Breast weight (633.9 g) was maximized at a Val:Lys ratio of 86 and a Leu:Lys ratio of 103. Conversely, breast yield (27.12%) was maximized at a Val:Lys ratio of 70 and Leu:Lys ratio of 192. Interestingly, live performance (BWG and FCR) was optimized at the lowest Leu:Lys ratios while breast meat yield was optimized at the highest Leu:Lys ratio indicating that BCAA influence body composition.
