Lysine Ratio Research Articles

An Estimation of the Requirements of the Standardized Ileal Digestible Tryptophan, Valine, Isoleucine and Methionine on Young Pigs’ (Up to 50 kg) Feed Efficiency: A Meta-Regression Analysis

Currently, the NRC amino acid (AA) requirements for pigs published in 2012 are used as a reference in variable swine industries. However, recent results in several articles suggest that the standardized ileal digestible (SID) AA–lysine (Lys) ratio significantly evolved over the last two decades, while some publications report inconsistent outcomes. Therefore, the present study used a meta-regression analysis to assess the relative ratio to lysine to maximize the feed efficiency of four essential amino acids (tryptophan, valine, isoleucine, and methionine) in pig diets. According to the PRISMA guidelines, articles examining the target AA requirement using a basal diet supplemented with varying levels of crystalline AA (tryptophan, valine, isoleucine, or methionine) were identified across Scopus, PubMed, and Science Direct. As a result, 23, 22, 16, and 9 articles using tryptophan, valine, isoleucine, and methionine were selected and categorized into experiments for inclusion in our meta-analysis. The results suggested that the requirements of tryptophan, valine, isoleucine, and methionine in our meta-regression analysis were superior to NRC recommendations, regardless of the regression models and the growth phases with significant RSQ values (RSQ ≈ 1). Also, the QUAD and CLP regression models emphasized higher requirements than the LP model for the great majority of amino acids and growth phases. The results of the QUAD and CLP models were selected as estimations of the amino acid requirements for pigs under challenged conditions, whereas the LP model was chosen to estimate the amino acid requirements of genetically improved pigs under a modern housing system. The results of this meta-regression analysis could be used to refresh the information on the NRC amino acids (AA) requirements for swine.

Effect of Dietary Standardized Ileal Digestible Arginine to Lysine Ratio on Reproductive Performance, Plasma Biochemical Index, and Immunity of Gestating Sows.

The aim of this study was to determine the optimal SID Arg: Lys ratio for maximizing the reproductive performance, immunity and biochemical parameters of sows during gestation, the colostrum composition, and the performance of their offspring. A total of 174 multiparous sows were randomly allocated to five treatment groups varying in dietary SID Arg: Lys ratios (0.91, 1.02, 1.14, 1.25 and 1.38) through modification of the levels of Arg or alanine supplementation (the total level of nitrogen was the same in all treatments). The results showed that increasing the dietary SID Arg: Lys ratio increased the number of piglets born alive (p < 0.05, linear and quadratic). The number of stillborn piglets, the birth weight variation of born alive piglets, the birth interval (p < 0.05, linear and quadratic) and the number of mummies (p < 0.05, quadratic) reduced with increasing the dietary SID Arg: Lys ratio. Broken-line regression analysis indicated that the optimal SID Arg: Lys ratio requirement for gestating sows to maximize the number of piglets born alive was 1.25. The content of non-fat solid, total solid, protein, and energy in colostrum increased linearly and quadratically (p < 0.05) with increasing dietary SID Arg: Lys ratio. Additionally, when increasing the dietary SID Arg: Lys ratio, the concentration of IgA (p < 0.05, quadratic) and IgM (p < 0.05, linear and quadratic) of plasma increased at day 90 of gestation; IgG (p < 0.05, linear and quadratic) concentration increased at day 110 of gestation of sows. The dietary SID Arg: Lys ratio had an increasing effect (p < 0.05, linear and quadratic) on plasma insulin levels at day 90 of gestation. Furthermore, there were increases in plasma concentrations of nitric oxide and ornithine at day 110 of gestation, Arg at day 90 and 110 of gestation (p < 0.05, linear and quadratic) and total protein at day 110 of gestation (p < 0.05, linear) with increasing dietary SID Arg: Lys ratio. The results of our study indicated that increases in the dietary SID Arg: Lys ratio during gestation resulted in an increase in the number of piglets born alive, a decrease in birth intervals, and an improvement in immunity and colostrum composition. The optimal SID Arg: Lys ratio for gestating sows to maximize the number of piglets born alive was 1.25.

Optimal glycine allowance levels in low-protein diets and the dynamic requirement model for broilers

This study aimed to investigate the effects of different glycine levels in low-protein diets on the growth, nitrogen deposition, and expression of intestinal amino acid and glucose transporters in broilers from 29 to 42 days of age, in order to determine the optimal glycine supplementation level. A total of 240 male broilers at 29 days old were randomly assigned to 5 groups: the control group with a crude protein level of 20%, and experimental groups with low-protein diets (LP130) containing 18% crude protein, supplemented with glycine to achieve standardized ileal digestible (SID) glycine + serine to lysine ratios of 134% (LP134), 140% (LP140), and 145% (LP145). The results showed that the LP134 group had similar growth performance and slaughter performance compared to the control group (P > 0.05), whereas other low-protein diet groups had significantly lower growth performance (P < 0.05). Regression analysis determined that the optimal ratio for SID glycine + serine to lysine was 137%. A dynamic model for glycine + serine requirements was established through binary regression analysis: y = 599.051 × BW^0.75 + 8.381 × ADG (R2 = 0.998, P < 0.001). Feeding LP134, LP140, and LP145 diets significantly improved nitrogen deposition rates in broilers (P < 0.05). Low-protein diets significantly upregulated mRNA levels of b0,+AT, EAAT3, and SGLT1 genes in the duodenum (P < 0.05). In conclusion, appropriate glycine supplementation in low-protein diets can enhance growth performance, and nitrogen deposition efficiency, and regulate the expression of intestinal amino acid and glucose transporters. The optimal ratio of SID glycine + serine to lysine in low-protein diets for broilers aged 29 to 42 days is 137%.

Methionine Source and Level Modulate Gut pH, Amino Acid Transporters and Metabolism Related Genes in Broiler Chickens.

This study determined the effects of two methionine (Met) sources at three total sulfur amino acids (TSAA) to lysine ratios (TSAA/Lys) on gut pH, digestive enzyme activity, amino acid transporter expression, and Met metabolism of broilers. The birds were randomly assigned to a 2 × 3 factorial arrangement with Met sources (dl-Met and dl-2-hydroxy-4-(methylthio)-butanoic acid (OH-Met)) and TSAA/Lys (0.58, 0.73, and 0.88) from 1 to 21 days. The results demonstrated that dl-Met and OH-Met supported the same growth performance, but high TSAA/Lys ratio reduced the feed intake and body weight (P < 0.05). OH-Met reduced the crop chyme pH and enhanced the jejunal lipase activity (P < 0.05). ATB0,+ expression decreased with increased dl-Met levels in the duodenum; the low TSAA/Lys ratio induced a stronger mRNA expression of basolateral Met transporters. OH-Met resulted in an increase of cystathionine β-synthase expression in the liver and a decrease in serum homocysteine levels at middle TSAA/Lys ratio compared with dl-Met treatment (P < 0.05). In conclusion, two Met sources support the same growth, but OH-Met acidified the crop chyme. The investigated transporter transcripts differed significantly along the small intestine. At the middle TSAA/Lys ratio, OH-Met showed a higher metabolic tendency of the trans-sulfuration pathway compared with dl-Met.

Varying the ratio of Lys: Met through enhancing methionine supplementation improved milk secretion ability through regulating the mRNA expression in bovine mammary epithelial cells under heat stress.

The ratio of lysine (Lys) to methionine (Met) with 3.0: 1 is confirmed as the "ideal" profile for milk protein synthesis, but whether this ratio is suitable for milk protein synthesis under HS needs to be further studied. To evaluate the molecular mechanism by which HS and Lys to Met ratios affect mammary cell functional capacity, an immortalized bovine mammary epithelial cell line (MAC-T) is incubated with 5 doses of Met while maintaining a constant concentration of Lys. The MAC-T cells was treated for 6 h as follow: Lys: Met 3.0: 1 (control 37°C and IPAA 42°C) or treatments under HS (42°C) with different ratios of Lys: Met at 2.0: 1 (LM20), 2.5: 1 (LM25), 3.5: 1 (LM35) and 4.0: 1 (LM40). RNA sequencing was used to assess transcriptome-wide alterations in mRNA abundance. The significant difference between control and other groups was observed base on PCA analysis. A total of 2048 differentially expressed genes (DEGs) were identified in the IPAA group relative to the control group. Similarly, 226, 306, 148, 157 DEGs were detected in the LM20, LM25, LM35 and LM40 groups, respectively, relative to the IPAA group. The relative mRNA abundance of HSPA1A was upregulated and anti-apoptotic genes (BCL2L1 and BCL2) was down-regulated in the IPAA group, compared to the control group (p < 0.05). Compared with the IPAA group, the relative mRNA abundance of anti-apoptotic genes and casein genes (CSN1S2 and CSN2) was up-regulated in the LM25 group (p < 0.05). The DEGs between LM25 and IPAA groups were associated with the negative regulation of transcription RNA polymerase II promoter in response to stress (GO: 0051085, DEGs of BAG3, DNAJB1, HSPA1A) as well as the mTOR signaling pathway (ko04150, DEGs of ATP6V1C2, WNT11, WNT3A, and WNT9A). Several DEGs involved in amino acids metabolism (AFMID, HYKK, NOS3, RIMKLB) and glycolysis/gluconeogenesis (AFMID and MGAT5B) were up-regulated while DEGs involved in lipolysis and beta-oxidation catabolic processes (ALOX12 and ALOX12B) were down-regulated. These results suggested that increasing Met supply (Lys: Met at 2.5: 1) may help mammary gland cells resist HS-induced cell damage, while possibly maintaining lactation capacity through regulation of gene expression.

114 Effects of greater levels of soy protein and methionine on periparturient health of sows

Abstract Sow prolificacy in the U.S. continues to trend greater, as does sow mortality. Replacement of soy protein (SBM) in sow diets with corn and purified amino acids (AA), may impact the health of highly prolific sows. In 2015, Denmark increased recommendations for SID methionine (MET) to SID lysine (LYS), MET:LYS to 32%, NRC (2012) recommend 27%. The primary objective of this research was to evaluate SBM and MET at greater levels for their effects on markers of health in the peripartum and lactation periods. A total of 38 parity 1 to 3 females (PIC 1050) were utilized with a starting body weight (BW) of 223.4kg ± 13.0 SD. On d 85 of gestation, sows were allocated by BW and parity to one of four treatments: 1 - 30% SBM (30% of diet), 36% MET:LYS; 2 - 15% SBM, 36% MET:LYS; 3 - 30% SBM, 27% MET:LYS; 4 - 15% SBM, 27% MET:LYS. Sows were fed dietary treatments 28 d pre-farrow, according to BW, and ad libitum throughout lactation. Body condition by caliper (BCS), BW, and backfat (BF) were measured on d 0, 21, 2 d post-farrow, and weaning. Sows were assigned a farrowing ease score of 1 to 4 (1-easy to 4-difficult) based on duration, restless activity, savaging, and assistance required. Continuous glucose monitors (CGM) were placed on a subset of sows (n = 12) on d 113 of gestation through 3 d post-farrow. Data were analyzed using the GLM procedure in SAS with sow serving as the experimental unit. A planned t-test was performed on CGM glucose data. Two sows were removed during lactation. The combined effect of 30% SBM and 36% MET:LYS produced an average lactation BW loss of 0.3 kg, while the 15% SBM and 27% MET:LYS treatment, diets similar to NRC, lost an average of 18.1kg. Sows fed the 30% SBM diets had less lactation BW loss than 15% SBM (Table 1; P &amp;lt; 0.10). Sows fed 36% MET:LYS lost less BW than those fed 27% MET:LYS (P &amp;lt; 0.05). The 36% MET:LYS group also lost less backfat during lactation and had lower pre- and post-farrow body temperatures than 27% MET:LYS (P &amp;lt; 0.01 and P &amp;lt; 0.05, respectively). While no differences in blood glucose were observed, in sows with CGM, greater levels of SBM decreased interstitial glucose concentrations (P = 0.055). In conclusion, greater inclusion of SBM and increasing the MET:LYS ratio in sow diets may improve periparturient changes in body condition and health outcomes.

95 Effects of increasing standardized ileal digestible valine:lysine ratio on growth performance in finishing pigs

Abstract Two experiments evaluated the effects of increasing standardized ileal digestible (SID) Val:Lys ratio on the growth performance of 38 to 67 kg (Exp. 1) and 90 to 116 kg (Exp. 2) finishing pigs. In Exp. 1, pigs (n = 647; DNA 600 × 241) were randomly allotted to 1 of 6 dietary treatments with 8 or 9 pigs per pen and 12 replications per treatment. Diets were corn-soybean meal-based, and low and high Val diets were manufactured and blended to create intermediate Val:Lys ratio diets. Diets were formulated to contain 0.90% SID Lys, and treatments consisted of SID Val:Lys ratios of 60%, 63%, 66%, 69%, 72%, and 75%. At the conclusion of the 27-d study, all pigs were fed a common diet for 30 d and then randomly re-allotted to 1 of 6 diets formulated to contain 0.65% SID Lys and SID Val:Lys ratios of 63%, 66%, 69%, 72%, 75%, and 78% (Exp. 2). In both experiments blood samples were collected from 3 pigs per pen on d 15 for plasma urea nitrogen (PUN) analysis. In Exp. 1, final body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI) increased (quadratic, P &amp;lt; 0.05) as Val:Lys increased (Table). Pigs fed the diet with 66% SID Val:Lys ratio had the greatest ADG, whereas pigs fed 72% SID Val:Lys ratio had the greatest ADFI. As the Val:Lys ratio increased, gain to feed ratio (G:F) decreased (linear, P &amp;lt; 0.05). Valine and Lys intake increased (quadratic, P &amp;lt; 0.05) as the Val:Lys ratio increased with the greatest intake observed at 72% SID Val:Lys. Valine and Lys intake per kg of gain increased (linear, P &amp;lt; 0.05) as the level of Val in the diet increased. Plasma urea nitrogen decreased (linear, P &amp;lt; 0.05) as the Val:Lys ratio increased. In Exp. 2, ADG and ADFI increased (linear, P &amp;lt; 0.05) as Val:Lys increased. However, for ADG there was little improvement from feeding greater than 69% SID Val:Lys. There were no linear or quadratic effects (P &amp;gt; 0.05) for SID Val:Lys on G:F or PUN. Valine intake, Lys intake, and Val intake per kg of gain increased (linear, P &amp;lt; 0.05) as the Val:Lys ratio increased. There were no differences (P &amp;gt; 0.05) observed in Lys intake per kg of gain. Based on the results of this study, it appears that 66% SID Val:Lys ratio maximizes ADG in 38to 67 kg pigs, and only small increases in ADG were observed when feeding greater than 69% SID Val:Lys for 90 to 116 kg finishing pigs.

90 Evaluating water- and feed-based arginine supplementation on newly weaned pig growth and gastrointestinal health

Abstract The objective of this experiment was to assess the influence of arginine (Arg) supplementation in water and/or feed on the growth performance and gastrointestinal health of newly weaned pigs. Pigs (n = 240; PIC 337 Χ 1050, Genus, Henderson, TN) were randomly allocated into 80 mixed-sex test pens and subjected to a 2 Χ 4 factorial design, with two levels of Arg supplementation in water (0% or 8% stock, dosed through a 1:128 proportioner) for the first phase (d 0-7), and four dietary arginine levels (0.85, 0.95, 1.05, and 1.15 standardized ileal digestible (SID) Arg to Lysine (Lys) ratios for the first two phases (d 0-7 and 7-21). All treatments were provided a common diet (0.96 SID Arg:Lys) for the last phase d 21- 42. One pig per pen underwent a dual sugar absorption test of lactulose at 500 mg/kg and mannitol at 50 mg/kg of body weight (BW) via gastric tube on d 7 and 21, with blood plasma collected 4 h post-administration. The pig tested on d 7 was subsequently euthanized for intestinal tissue collection. Pen growth performance and feed disappearance were evaluated for 3 phases; d 0-7, 7-21, and 21-42. The statistical analysis utilized generalized linear mixed model methods (SAS 9.4, Cary, NC) with the main effects of SID Arg:Lys in the feed and Arg level within the water, and the interaction between the two. Pen was the experimental unit. Orthogonal contrasts were tested for the linear and quadratic effects of the diet. Growth performance during the 1st period exhibited variability, reflected by negative gain to feed ratio (G:F), caused by health challenges of Rotavirus A. Consequently, data were analyzed separately for each phase. Increasing dietary SID Arg:Lys caused a significant linear effect (improvement; P = 0.04) on final BW (18.47 and 21.90 kg, for 0.85 and 1.15 SID Arg:Lys, respectively). However, discernible differences between dietary treatments were not observed (P &amp;gt; 0.1). Similarly, a trend (P = 0.09) suggested a linear impact of dietary SID Arg:Lys on average daily gain during the third phase (d 21-42). In terms of intestinal absorption and morphology, Arg supplementation, whether through water or diet, had no effect on lactulose and mannitol absorption on both d 7 and d 21, nor did it impact villous height, crypt depth, or the villi:crypt ratio in ileum tissues collected on d 7 post-weaning. In conclusion, dietary supplementation with Arg increased final BW but had no clear impacts on intestinal health within the variables measured, potentially impacted by the rotavirus diagnosis in the first week post wean.

Effects of different dietary threonine and glycine supplies in broilers fed low-protein diets.

The reduction of crude protein (CP) content of broiler diets with balanced amino acid supply can increase the nitrogen (N) utilization efficiency and reduce ammonia emission, the risk of many health problems in birds. Feeding low protein (LP) diets without the impairment of performance traits needs the optimized dietary levels of threonine (Thr) and the non-essential amino acid (AA) glycine (Gly) and serine (Ser). However, the required concentrations and interactions of Thr and Gly + Ser, expressed as Gly equivalent (Glyequi), in LP diets are not fully understood. Therefore, the aim of this study was to investigate the effects of three LP (LP1-3) grower (11-24 days) and finisher (25-35 days) diets with 2% CP reduction compared to the control (C), differing in standardized ileal digestible (SID) Thr to lysine (Lys) ratio (C, LP1, LP3: 63%, LP2: 72%) and Glyequi levels (C: 15.65 g/kg, LP1: 13.74 g/kg, LP2: 13.70 g/kg, LP3: 15.77). The LP treatments did not impair the performance traits of broilers. The LP2 treatment with increased SID Thr-to-Lys ratio (+9.0%) resulted in significantly higher body weight gain and a more advantageous feed conversion ratio in the whole fattening compared to the control treatment with normal CP level (p < 0.05). The LP3 treatment containing swine meat meal with similar Glyequi levels compared to the normal CP treatment led to the most advantageous feed conversion ratio in the finisher phase and the highest nitrogen retention efficiency (p < 0.05). However, the LP3 treatment with a high starch-to-CP ratio negatively influenced the relative carcass weight and the ratio of abdominal fat of broilers (p < 0.05).

Effect of dietary electrolyte balance and arginine to lysine ratio on hematological, antioxidant and immunological traits in dual-purpose breeding hens under cyclic heat stress condition

A total of 245 hens and 35 cocks (32 weeks age) were assigned to seven treatment groups (five replicates with seven hens and one cock) to investigate the effect of dietary electrolyte balance (DEB) and arginine to lysine ratio (Arg/Lys) on birds’ physiological and biochemical traits under cyclic heat stress (CHS) condition. Birds were housed in an environmentally controlled facility having four sectors. The first group (positive control, PC) was kept under thermoneutral conditions and fed diet with DEB of 180 mEq and Arg/Lys of 1.25, whereas the other six treatments were kept in the second sector under CHS and fed diet with DEB and Arg/Lys equal to: 180 mEq and 1.25 (negative control, NC); 250 mEq and 1.25; 320 mEq and 1.25; 180 mEq and 1.37; 250 mEq and 1.37; 320 mEq and 1.37, respectively. Hens on NC group had significantly decreased red blood cells (RBCs), white blood cells (WBCs) and its fractions. The groups fed different DEB and Arg/Lys in diet significantly enhanced the blood parameters and plasma lipid profile compared NC group. Hens under CHS fed on 250 and 320 DEB with 1.37 Arg/Lys recorded the lowest concentration of low-density lipoprotein (LDL) compared with the other groups. Triiodothyronine (T3) activity was not differed among groups, while T4 activity in layer exposed to CHS (NC group) recorded the highest activity compared to PC. From findings, it can be concluded that laying hens fed a diet having DEB 250 mEq with 1.37 Arg/Lys could be successfully applied to counteract the adverse effect of CHS and to improve blood hematological and biochemical traits, antioxidants, and immunity response.

Arginine: lysine ratio influences on performance, egg quality, haematology, biochemistry, antioxidant status and immunity of dual-purpose breeding hens exposed to cyclic heat stress

The aim of this study was to investigate the effects of arginine/lysine ratio (Arg/Lys) on the productive and reproductive performance, egg quality, immune and physiological parameters of hens reared under cyclic heat stress condition (CHS). A total of 140 females, and 20 males of 32 weeks of age, were randomly assigned to 4 treatment groups. The first group (positive control, PC) fed the basal corn-soybean meal diet with an Arg/Lys ratio of 1.25 and was kept at 22–24°C and 45–55% relative humidity. The other 3 treatments fed basal diet in which the Arg/Lys was set at 1.25, 1.37 and 1.50, respectively and were submitted to cyclic heat stress conditions (CHS, 38 °C ± 1, 55–65% RH) for three successive days a week from 10:00 am until 14:00. The results showed a reduction h-day egg production (EP), feed conversion ratio (FCR), shell weight, fertility and hatchability, hemoglobulin (Hgb), hydrogen power (pH) and plasma calcium and phosphorus concentrations for the negative control (NC) group compared to the positive control group. However, changing Arginine (Arg)/lysine (Lys) ratio in the basal diets for the groups under CHS from 1.25 to 1.37 and 1.50 improved EP, egg weight, egg mass and FCR when compared to NC group. Total lipid, total cholesterol, low-density lipoprotein, triglycerides, and malondialdehyde activity for the NC group significantly increased, while increasing the ratio of Arg/Lys to 1.37 and 1.50 improved the mentioned traits as to PC group. Our findings indicated that diets with an Arg/Lys ratio of 1.37 administered to laying hens farmed under cyclic heat stress conditions, are able to improve the laying performance, egg quality, fertility, hatchability, blood hematological and biochemical constituents, antioxidants, and immunity indices in comparison to the other groups, including the PC one. Thus, diets with an Arg/Lys ratio of 1.37 can be used to recover the adverse effect of CHS.

PRODUCTIVITY OF TURKEYS AT DIFFERENT RATIOS OF LYSINE AND METHIONINE IN COMPOUND FEED

The article examines the effect of using complete ration compound feed with different ratios of lysine and methionine on the productivity of turkeys. Experimental studies were performed on turkeys of the BIG 6 cross-breeding meat direction. Five experimental groups of birds were formed by the method of analog groups at the age of one day. The experiment lasted 126 days and was divided into two periods: comparative (7 days) and main (119 days). During the comparative period, the experimental turkeys consumed feed of the control group. In the main period of the experiment, the proportion of methionine relative to lysine decreased or increased by 5 or 10% according to growing periods. It was established that the different ratio of lysine and methionine in compound feed for turkeys affects its productivity in different ways. In particular, at the end of the experiment, at the age of 126 days, the highest live weight was achieved by turkeys that consumed compound feed with an increase in the proportion of methionine relative to lysine by 5 and 10% - they outnumbered the counterparts of the control group, respectively, by 5.9 (p&lt;0.05) and 3.6%. Poultry that received compound feed with a reduced proportion of methionine relative to lysine by 10 and 5% were inferior to control peers by 4.4 (p&lt;0.05) and 2.2%, respectively, according to the mentioned indicator. The description of the growth of turkeys using mathematical methods confirmed the S-shaped ascending shape of the growth curve with high coefficients of determination for each experimental group. It was found that in almost all periods of the experiment, turkeys that consumed compound feed with a higher level of methionine relative to lysine prevailed in terms of average daily live weight gains of their counterparts fed compound feed with a lower proportion of methionine relative to lysine. In general, turkeys that consumed compound feed with an increase in the proportion of methionine relative to lysine by 5 and 10% were characterized by higher average daily live weight gains - it exceeded the control analogues by the mentioned indicator by an average of 4.6 and 2.2%, respectively. Turkeys that received combined feed with a reduced proportion of methionine relative to lysine by 10 and 5% were inferior to peers of the 1st group by 4.3 and 2.1%, respectively. It was established that the relationship between the ratio of lysine and methionine in compound feed for young turkeys and its average daily weight gain is described by a polynomial line with a reliable approximation coefficient R2=1. At the same time, the correlation analysis showed that there is a direct average relationship between these phenomena (rs =0.64, p˂0.05).

Impact of increasing dietary standardized ileal digestible arginine to lysine ratio from 0.85 to 1.15 and water-based arginine supplementation on growth performance and gut integrity of weaned pigs.

The objective of this experiment was to assess the influence of arginine (Arg) supplementation in water and/or feed on the growth performance and gastrointestinal health of newly weaned pigs. Two hundred and forty pigs (5.06kg; PIC, Hendersonville, TN) were randomly allocated into 80 mixed-sex pens (3 pigs/pen) and subjected to a 2 × 4 factorial design. Two levels of Arg were supplemented in water (0% or 8% stock, dosed through a 1:128 proportioner) for the first phase (days 0 to 7), and four dietary arginine levels (0.85, 0.95, 1.05, and 1.15) standardized ileal digestible (SID) Arg to Lysine (Lys) ratios for the first two phases (days 0 to 7 and 7 to 21). All treatments were provided a common diet (0.96 SID Arg:Lys) for the last phase days 21 to 42. One pig per pen underwent a dual sugar absorption test of lactulose at 500mg/kg and mannitol at 50mg/kg of body weight (BW) via gastric tube on days 7 and 21 postweaning, with blood plasma collected 4h later. The pig tested on day 7 was subsequently euthanized for intestinal tissue collection. Pen growth performance and feed disappearance were evaluated for 3 phases: days 0 to 7, 7 to 21, and 21 to 42 postweaning. The statistical analysis used linear models to examine the effects of SID Arg:Lys in the feed, Arg level in water, and their interactions, with pen as the experimental unit. Orthogonal contrasts were used to test the linear and quadratic effects of increasing SID Arg:Lys in the diet. Growth performance during the first period exhibited variability, reflected by negative gain-to-feed (G:F) ratios, caused by the enteric health challenge. Consequently, data were analyzed separately for each phase. Increasing dietary SID Arg:Lys caused a linear improvement (P = 0.04) in final BW (18.47 and 21.90kg, for 0.85 and 1.15 SID Arg:Lys, respectively). A trend (P = 0.09) suggested a linear impact of dietary SID Arg:Lys on average daily gain during days 21 to 42. Arg supplementation, whether administered through water or diet, did not affect lactulose and mannitol absorption on both days 7 and 21, nor did it alter histological measurements in the collected ileum tissues on day 7 postweaning. In conclusion, increasing dietary SID Arg:Lys increased final BW but had no clear impacts on intestinal health within the parameters measured, potentially impacted by the rotavirus diagnosis in the first week post-wean.

266 Interactive Effects of Dietary Isoleucine and Valine Ratios to Lysine in Response to Varying Leucine to Lysine Ratios on Hepatic Protein Expression in Commercial Broilers

Abstract A central composite design (CCD) study was conducted to understand the relationship among dietary branched chain amino acid (BCAA) ratios and expression of proteins related to amino acid and protein metabolism in the liver of broilers. 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 a 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 selected, euthanized, and liver tissue samples were collected for protein extraction and proteomic analysis via data independent acquisition protein sequencing with a timsTOF Pro 2 LC/MS/MS and Spectronaut 15 software. Dihydrolipoamide acetyltransferase (PDHX), aspartate aminotransferase (GOT2), branched-chain-amino-acid aminotransferase (BCAT1), diphosphomevalonate decarboxylase (MVD), acylamino-acid-releasing enzyme (APEH), and aspartate aminotransferase (GOT1) were identified and quantified. Protein quantification data were analyzed as a CCD using the RSREG procedure of SAS v. 9.4 with significance declared at P ≤ 0.10. When the individual AA effect in the response surface (RS) regression analysis was P ≤ 0.2, raw protein quantification data were analyzed as a 1-way ANOVA and the PDIFF option of SAS set at P ≤ 0.1 using the GLIMMIX procedure. The RS model for MVD and APEH expression were significant (P ≤ 0.0511). However, models for PDHX, GOT2, BCAT1, and GOT1 were not significant (P ≥ 0.1356) and the R2 values ≤ 0.25 for all proteins did not allow for prediction of protein expression means. No linear, quadratic, cross product, or individual BCAA ratio effects were observed for PDHX, GOT2, and BCAT1 (P ≥ 0.1977). A linear model for MVD and APEH protein expression (P ≤ 0.8030) and quadratic model for APEH (P ≤ 0.0552) were significant. MVD increased as Val:Lys ratio increased when Leu:Lys and Ile:Lys were fixed at 148 and 63 or 170 and 70, respectively (P ≤ 0.0926). Low Val:Lys ratio expressed the least hepatic APEH expression when Leu:Lys and Ile:Lys ratios were 148 and 63 or 125 and 70, respectably (P ≤ 0.0153). Hepatic MVD expression decreased as Leu:Lys ratio increased when Val:Lys and Ile:Lys were 75 and 63, respectably (P ≤ 0.0044). GOT1 expression was higher with 170 Leu:Lys ratio compared with 125, when Val:Lys and Ile:Lys ratio were 68 and 70, respectably (P ≤ 0.0460). APEH was greater with a low Ile:Lys ratio when Val:Lys and Leu:Lys were 68 and 125, respectably (P ≤ 0.0786). Varying concentrations of dietary BCAA and their interactions seem to alter hepatic protein expression and may help explain the mechanisms underlying their influence on broiler growth.

265 Interactive Effects of Dietary Isoleucine and Valine Ratios to Lysine in Response to Varying Leucine to Lysine Ratios on Pectoralis Major Muscle Protein Expression in Commercial Broilers

Abstract Optimizing the dietary concentrations and ratios of branched-chain amino acids (BCAA) is necessary to optimize broiler chicken growth performance and carcass meat yield. A central composite design (CCD) study was conducted to understand the impact of dietary BCAA concentrations and ratios on Pectoralis major (PM) muscle protein expression involved in mTOR and related protein synthesis pathways as well as and investigate the mechanisms behind how BCAA ratios affect broiler growth and muscle protein accretion. A total of 2,592 d-old Ross 344 × 708 male broilers were randomly placed in 144 floor pens (n = 18 birds per pen). Before the initiation of the experimental finisher phase, all pens were standardized to contain 15 birds per pen. 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 valine:lysine (Val:Lys; 64 to 87), leucine:lysine (Leu:Lys; 110 to 185), and isoleucine:lysine (Ile:Lys; 52 to 75). 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. Ribosomal protein S6 kinase (RPS6KA3), eukaryotic elongation factor 2 (EEF2), eukaryotic translation initiation factor 4B (EIF4B), eukaryotic translation initiation factor 4E (EIF4E), CAP-Glycine domain containing linker protein 1 (CLIP1), mitogen-activated protein kinase 3 (MAPK3), Protein kinase domain-containing protein (MAP2K1), Dual-specificity mitogen-activated protein kinase kinase 2 (MAP2K2), paxillin (PXN), and regulator complex protein (LAMTOR3) 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 models for RPS6KA3, EEF2, EIF4B, EIF4E, MAPK3, MAP2K1, MAP2K2, CLIP1, PXN, and LAMTOR3 were not significant (P ≥ 0.926; R2 values ≤ 0.1). No linear (P ≥ 0.5223), quadratic (P ≥ 0.0.634) or cross product (P ≥ 0.6238) regression effects were observed for any of the proteins analyzed. A minimum stationary point was observed for RPS6KA3, EEF2, MAPK3, and LAMTOR3. However, optimal values for the other proteins could not be obtained due to stationary saddle points. Overall, the results in this study indicate that varying concentrations of dietary BCAA may not impact expression of proteins related to broiler skeletal muscle growth on d 35 following the 15-d treatment period, despite the influence on live performance. This is a limitation of this study and suggests that if the mTOR pathway was involved it was not still differentially up- or down-regulated at this time point. Further investigation and new studies with multiple time points will be required to better understand the mechanisms behind how BCAA impact broiler growth and muscle development.

186 Amino Acid Digestibility of Various Protein-Based Ingredients Using the Precision-Fed Cecectomized Rooster Assay

Abstract Given their high protein quality and sustainable production practices, there is growing interest in using single cell-based proteins in pet foods. Because there has been a lack of testing on these proteins, the objective of this experiment was to determine the amino acid (AA) digestibilities of a single cell protein and other protein-based ingredients using the precision-fed cecectomized rooster assay. Test ingredients included: Calysta microbial protein (MP), chicken meal (CM), corn gluten meal (CGM), pea protein (PP), and black soldier fly larvae (BSFL). All animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. Thirty cecectomized roosters (n = 6/ingredient) were randomly assigned to test ingredients. After 24 h of feed withdrawal, roosters were tube-fed 15 g of test ingredient and 15 g of corn. Following crop intubation, excreta were collected for 48 h. Endogenous corrections for AA were made using 5 additional cecectomized roosters. Digestible indispensable AA score (DIAAS)-like values were calculated to determine protein quality according to AAFCO nutrient profiles, FEDIAF nutritional guidelines, and NRC recommended allowances for adult dogs, adult cats, growing puppies, and growing kittens. Data were analyzed using the Mixed Models procedure of SAS 9.4, with P &amp;lt; 0.05 being significant. All of the reactive lysine:total lysine ratios, an indicator of heat damage, were greater than 0.9 except for CM (0.86). All indispensable AA had digestibilities &amp;gt;85% for MP, with indispensable AA digestibilities being &amp;gt;80% for all ingredients. In general, CGM had the greatest AA digestibilities, while CM had the least AA digestibilities. Two exceptions were the digestibilities of lysine and tryptophan, which were greatest in MP. Lysine digestibility for MP (92.3%) was greater (P &amp;lt; 0.01) than that of all other ingredients. Tryptophan digestibility for MP (97.2%) was greater (P &amp;lt; 0.0001) than that of CM, CGM, and PP. Threonine and valine digestibilities were also greater for MP. Threonine digestibility was greatest for CGM (91.0%) and MP (88.6%), being greater (P &amp;lt; 0.0001) than that of the other ingredients. Valine digestibility was greatest for CGM (93.3%), PP (89.3%), and MP (89.3%), being greater (P &amp;lt; 0.001) than that of CM. DIAAS-like calculations estimated the protein quality of each ingredient, with the limiting AA of each depending on the reference used (NRC; AAFCO; FEDIAF) and life stage (growing; adult) and species (dog; cat) of animal in question. For dogs, limiting AA were most commonly methionine, threonine, and tryptophan. For cats, limiting AA were most commonly lysine and methionine. Further research in dogs and cats is necessary to confirm sufficient palatability and digestibility. However, our data suggest that the MP tested is a high-quality protein source with high AA digestibilities, and may serve as a valuable protein alternative for pet foods.

PSVIII-18 Standardized Amino Acid Digestibility and Nitrogen-Corrected True Metabolizable Energy of Frozen Raw, Freeze-Dried Raw, Fresh, and Extruded Dog Foods Using Cecectomized and Conventional Rooster Assays

Abstract Processing conditions, particularly temperature and duration of heating, impact the digestibility of pet foods. Various alternative commercial pet food formats are now available, but few have been well tested. Therefore, the objective of this study was to determine the amino acid (AA) digestibility and nitrogen-corrected true metabolizable energy (TMEn) of frozen raw, freeze-dried raw, fresh, and extruded dog foods using the precision-fed cecectomized and conventional rooster assays. The diets tested were Chicken and Barley Recipe [extruded diet; Hill’s Science Diet (EXT)], Chicken and White Rice Recipe [fresh diet; Just Food for Dogs (FRSH], Chicken Formula [raw frozen diet; Primal (FRZN)], Chicken and Sorghum Hybrid Freeze-dried Formula [hybrid freeze-dried raw diet; Primal (HFD)], and Chicken Dinner Patties [raw freeze-dried diet; Stella &amp; Chewy (FD)]. Two precision-fed rooster assays utilizing Single Comb White Leghorn roosters (1.5 to 2.5 yr, 2.5 to 3 kg) were conducted. In the first assay, 20 cecectomized roosters (n = 4/treatment) were used to determine AA digestibility. In the second assay, 20 conventional roosters (n = 4/treatment) were used to determine TMEn. In both assays, roosters were crop intubated with 12 g of test diet and 12 g of corn, and then excreta were collected for 48 h. The reactive lysine:total lysine ratios were 0.94, 0.96, 0.93, 0.93, and 0.95 for the EXT, FRSH, FRZN, HFD, and FD diets, respectively. In general, FD had the greatest AA digestibilities and EXT had the least AA digestibilities. Arginine digestibilities were different (P &amp;lt; 0.05) across all diets and in this pattern: FD &amp;gt; FRZN &amp;gt; FRSH &amp;gt; HFD &amp;gt; EXT. Isoleucine digestibilities were different (P &amp;lt; 0.05) across all diets, but with a slightly different pattern: FD &amp;gt; FRZN &amp;gt; FRSH &amp;gt; EXT &amp;gt; HFD. Lysine digestibility was greater (P &amp;lt; 0.05) in FD and FRZN than EXT, with other diets being intermediate. Methionine digestibility was greater (P &amp;lt; 0.05) in FD than FRSH, with other diets being intermediate. Threonine digestibility was greater (P &amp;lt; 0.05) in FD than EXT, with other diets being intermediate. Valine digestibilities were different (P &amp;lt; 0.05) across all diets and in this pattern: FD &amp;gt; FRZN &amp;gt; EXT &amp;gt; FRSH &amp;gt; HFD. Digestibilities of the other essential AA were not different among diets. TMEn was greater (P &amp;lt; 0.05) in FRZN than FD, FRSH, and EXT, greater (P &amp;lt; 0.05) in HFD than FRSH and EXT, and greater (P &amp;lt; 0.05) in FD than EXT. In conclusion, our results support the notion that diet processing impacts AA digestibility, with freeze-dried raw, frozen raw, and fresh diets consistently having greater digestibility coefficients, as well greater TMEn, than the extruded diet. More research in dogs is necessary to test the effects of these diet formats on palatability, digestibility, stool quality, and other physiologically relevant outcomes.

240 Comparing Increasing Tryptophan: Lysine Ratios in Distiller Dried Grains-Based Diets with or without Distiller Dried Grains withdrawal Strategy on Growth and Carcass Performance of Grow-Finish Pigs

Abstract A total of 6,240 pigs [DNA 600 × PIC 1050; initial body weight (BW) = 22.5 ± 0.20 kg], divided into 2 groups, were used in 119- or 120- day study comparing increasing Trp:Lys ratio in diets with DDGS or a DDGS withdrawal strategy on growth and carcass performance and carcass fat iodine value of grow-finish pigs. Pigs were randomly allotted to 1 of 7 dietary treatments with 30 to 36 pigs per pen and 26 replications per treatment. Diets were fed in 4 phases (approximately 23 to 44, 44 to 71, 71 to 104, and 104 kg to market). Diets included a control corn-soybean meal-based diet formulated to a 19% SID Trp:Lys ratio, 4 diets with 30% DDGS fed in all four phases and formulated to achieve 16%, 19%, 22%, or 25% SID Trp:Lys ratio, respectively, and 2 DDGS withdrawal strategy diets: 19% SID Trp:Lys with 30% DDGS in phase 1 through 3 and then in phase 4, 0% DDGS with either a 19 or 25% Trp:Lys ratio. Overall, BW, ADG, ADFI, and G:F increased (linear, P &amp;lt; 0.05) as SID Trp:Lys ratio increased in diets with 30% DDGS fed in all 4 phases (Table). Pigs fed diets containing a SID Trp:Lys ratio of 19% and 30% DDGS from phases 1 through 3 and 0% DDGS in phase 4 had the greatest numeric ADG and ADFI for the overall study, but was not different than pigs fed the control for ADG, or the 25% Trp:Lys withdrawal treatment and the 30% DDGS diets with 25% Trp:Lys ratio throughout the study for ADG and ADFI. Hot carcass weight and carcass yield increased (quadratic, P &amp;lt; 0.05) as Trp:Lys ratio increased. Carcass fat samples were taken from the loin-butt junction and analyzed for iodine value. Pigs fed the control diet had decreased (P &amp;lt; 0.05) carcass fat iodine value compared with pigs fed DDGS throughout the study, with pigs fed the two DDGS withdrawal strategies having decreased (P &amp;lt; 0.05) iodine values compared with pigs fed 30% DDGS in all 4 phases. In summary, increasing the SID Trp:Lys ratio in diets with 30% DDGS resulted in a linear improvement in ADG, ADFI, G:F, and BW but did not influence iodine values. Removing DDGS from the diet in the last period reduced carcass fat iodine value and increased growth rate during the withdrawal period compared with pigs fed 30% DDGS throughout, indicating value in a DDGS withdrawal strategy.

237 Effects of Increasing Soybean Meal and Valine:Lysine and Tryptophan:Lysine Ratios on Finishing pig Performance

Abstract A total of 621 pigs (DNA 241 × 600; initially 62.9 kg) were used in a 65-day growth trial to determine the effect of increasing soybean meal (SBM) and Val:Lys and Trp:Lys (AA) ratios on finishing pig performance. Experimental diets were corn-soybean meal-based containing 25% DGGS and fed in 3 phases. The 6 dietary treatments were arranged in a 3 × 2 factorial, with main effects of SBM level (Low, Medium, High) and AA ratios (Standard, High). Ratios of Trp:Lys were: Phase 1: Standard 19, High 24%, Phase 2: Standard 19, High 23%, and Phase 3: Standard 19, High 23%. Ratios of Val:Lys were: Phase 1: Standard 70 to 83, High 87 to 88%, Phase 2: Standard 70 to 83, High 88%, and in Phase 3: Standard 76 to 96, High 96%. The additional amino acids provided by increasing levels of SBM in diets with standard AA ratios were expected to result in a greater ADG by balancing out the increased leucine from corn. Conversely, ADG was expected to stay the same as SBM increased when the Val:Lys and Trp:Lys ratios were increased. Pens of pigs were assigned to treatments in a randomized complete block design with BW as a blocking factor. There were approximately 10 pigs per pen and 12 pens per treatment. No evidence (P &amp;gt; 0.05) of SBM × AA ratio interactions or treatment differences was observed for any response criteria for phases 1 and 2 (Table). In phase 3, a marginally significant SBM × AA ratio interaction was observed for ADG (P = 0.084). The medium level of SBM with standard AA ratios resulted in greater ADG compared with other SBM levels (quadratic, P = 0.003), whereas no differences in ADG were observed with increasing SBM when Val:Lys and Trp:Lys ratios were increased (P = 0.501). Additionally, G:F increased at the medium level of SBM in phase 3 (quadratic, P = 0.007). In spite of the improvements observed in phase 3, there were no significant differences (P &amp;gt; 0.10) observed in overall ADG or ADFI. A marginally significant SBM × AA ratio interaction was observed for overall G:F (P = 0.052). Increasing SBM in diets with greater Val:Lys and Trp:Lys ratios resulted in decreased G:F (P = 0.049), whereas no difference in G:F was observed with increasing SBM in diets with standard AA ratios (P = 0.435). In conclusion, in early finishing there were no responses to increasing SBM; however, in the late finishing period when diets included 0, 4 or 8% SBM, pigs fed 4% SBM diets with standard Val:Lys and Trp:Lys ratios had increased ADG and G:F. Throughout the study, increasing Val:Lys and Trp:Lys ratios had little effect on pig performance.

20 How do Producers and Nutritionists Determine Which Levers to Pull to Optimize Feed Cost and Profitability Under Differing Economic Conditions?

Abstract Numerous factors including geopolitical unrest, supply chain disruption, government policies, and hyperinflation have resulted in a global increase in the cost of feed ingredients. Pork producers and swine nutritionists continuously answer the tricky question of how to best manage feed costs to maximize profitability under an everchanging economic landscape. Applied nutritionists must design and implement feeding programs that take into account and balance several key nutrition levers including energy, SID lysine to energy ratio, SID amino acid to lysine ratios, and feed processing along with factors including ingredient prices, pork price, barn space, feed mill throughput, and pig livability. Biological and economical models are developed and utilized to assist with prediction of key performance and profitability outcomes leveraging results from published and unpublished controlled research trials along with historical production data. The objective of this presentation is to provide insights into the decision-making process for feeding program design and implementation under current and theoretical economic situations.