Addition Of Ile Research Articles

Including dietary valine and tryptophan, but not isoleucine, above the requirement for growing pigs may partly ameliorate negative effects of excess leucine from corn protein on nitrogen balance and growth performance

Two experiments were conducted to test the hypothesis that increasing concentrations of dietary L-valine, L-isoleucine, or L-tryptophan in diets containing excess leucine (Leu) from corn protein will alleviate negative effects of excess dietary Leu on N balance and growth performance of growing pigs. In Exp. 1, 72 barrows (body weight: 33.9 ± 2.6 kg) were housed in metabolism crates and randomly allotted to 8 dietary treatments in a 12-day experiment. A basal diet based on corn and a high-protein corn product was formulated (16.9 mega joule/kg gross energy and 12.7 g/kg lysine). Two levels of crystalline L-isoleucine (0 or 1.0 g/kg), two levels of crystalline L-valine (0 or 1.0 g/kg), and two levels of crystalline L-tryptophan (0 or 0.5 g/kg) were added to the basal diet for a total of 8 diets that were used in a 2 × 2 × 2 factorial. Results indicated that fecal N output increased if isoleucine (Ile) was added to diets without adding valine (Val), but that was not the case if Val was added (interaction, P < 0.05). Isoleucine addition to diets reduced N retention, but N retention increased with tryptophan (Trp) addition to diets without valine addition, but not if Trp was added to diets with added Val (interaction, P < 0.05). The biological value of protein increased if Trp was added to diets without addition of Ile, but if Ile was added, Trp addition did not increase the biological value of protein (interaction, P < 0.05). In Exp. 2, a total of 288 growing pigs (body weight: 28.6 ± 2.5 kg) were randomly assigned to 9 dietary treatments in a 28-day growth performance experiment. There were 2 barrows and 2 gilts per pen and 8 replicate pens per treatment. A control diet based on corn and soybean meal (16.5 mega joule/kg gross energy and 11.1 g/kg lysine) was used in Exp. 2 in addition to the 8 diets used in Exp. 1. Results indicated that final body weight and average daily gain of pigs fed the control diet were greater (P < 0.001) than for pigs fed all other diets, except pigs fed the diet with addition of both L-valine and L-tryptophan. Pigs fed the control diet also had greater (P < 0.001) plasma concentrations of Trp and Val than pigs fed the basal diet or diets not containing L-tryptophan or L-valine, respectively. In conclusion, adding Ile alone reduced N retention, but adding Trp alone or in combination with Ile or Val increased N retention. The combination of Val and Trp supplementation may be beneficial for preventing detrimental effects of excess Leu on growth performance of pigs.

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.

Egg production and quality responses to increasing isoleucine supplementation in Shaver white hens fed a low crude protein corn-soybean meal diet fortified with synthetic amino acids between 20 and 46 weeks of age

The present study evaluated production performance responses to Ile supplementation in laying hens fed low crude protein (LCP), amino acid (AA) balanced diets. A total of 179 Shaver white pullets were distributed into 30 battery cages (6 birds/cage, n = 6) and observed over the course of 27 wk in a 2-phase (20 to 27 and 28 to 46 wk of age) feeding program. Five isocaloric diets were formulated for standardized ileal digestible (SID) Lys intake of 750 and 710 mg/D in phase 1 and 2, respectively, and included a positive control with standard levels of crude protein (CP) (CON; 18 and 16% CP for phases 1 and 2), and 4 LCP diets (16 and 14% CP for phase 1 and 2, respectively) with graded levels of Ile to satisfy SID Ile:Lys ratios of 70 (Ile70), 80 (Ile80), 90 (Ile90), and 100% (Ile100). Based on analyzed dietary AA, the calculated SID Ile:Lys of LCP diets were 75, 84, 88, 99% and 66, 72, 82, 95% for phase 1 and 2, respectively. Dietary treatments significantly (P < 0.05) affected feed intake, hen-day egg production (HDEP), egg weight (EW), feed conversion ratio, and egg quality (Haugh unit) and composition (yolk to albumen). Lowering dietary CP negatively affected HDEP with a 3.3 and 1.5% reduction in phase 1 and 2, respectively, and this was restored with the addition of Ile (P < 0.001) suggesting that Ile was limiting in the LCP basal diet. Average EW was reduced in Ile100 only; however, the Ile:Lys appeared to influence egg size uniformity, with Ile90 producing a greater proportion of large (56 g ≤ EW > 63 g) eggs, suggesting that Ile may be used to manipulate EW at the expense of HDEP. Overall, the results indicated that CP in laying hen diets can be reduced by 2% units if fortified with synthetic AA (Met, Lys, Thr, Trp) + Ile, with optimal responses observed between 82 and 88% SID Ile:Lys.

Isoleucine Regulates the Synthesis of Pancreatic Enzymes via the Activation of mRNA Expression and Phosphorylation in the Mammalian Target of Rapamycin Signalling Pathways in Pancreatic Tissues.

This study aimed to investigate the effects of isoleucine (Ile) on the synthesis and secretion of digestive enzymes and cellular signalling in the pancreatic tissue of dairy goats. The pancreatic tissues were incubated in buffer containing 0, 0.40, 0.80, and 1.60 mM Ile. High levels of Ile significantly increased the buffer release and total concentration of ɑ-amylase in the tissues (P < 0.001). The total trypsin and chymotrypsin concentrations in each of the Ile groups were significantly higher than those in the control group (P < 0.05); however, lipase was not affected. High levels of Ile significantly increased ɑ-amylase mRNA expression (P < 0.001) but had no effect on the mRNA expression of trypsin, chymotrypsin, or lipase. Ile did not affect S6K1 phosphorylation levels. High levels of Ile significantly increased the expression of the γ isoform of 4EBP1 (P < 0.001), which indicated that the phosphorylation of 4EBP1 was significantly increased. The phosphorylation level of eEF2 gradually decreased with the addition of Ile (P < 0.001). These results suggested that high doses of Ile can regulate the excretion of enzymes, especially ɑ-amylase, in the pancreatic tissues of dairy goats by modulating mTOR signalling, and this regulation is independent of the mTOR-S6K1 pathway.

Isoleucine, leucine, methionine, and threonine effects on mammalian target of rapamycin signaling in mammary tissue

Improved representation of postabsorptive N metabolism in lactating dairy cows requires a better understanding of protein synthesis regulation in the mammary glands. This study aimed to determine the quantitative effects of Ile, Leu, Met, and Thr on the phosphorylation state of signaling proteins that regulate protein synthesis. The experiment used a composite design with a central point, 2 axial points per AA, and a complete 24 factorial. All of the other AA were provided at the concentrations in Dulbecco's modified Eagle's medium. The experiment was replicated with tissues from 5 lactating cows. Mammary tissue slices (0.12±0.02g) were incubated for 4h. Total and site-specific phosphorylated mammalian target of rapamycin (mTOR; Ser2448), eukaryotic elongation factor (eEF) 2 (Thr56), ribosomal protein S6 (Ser235/236), and eukaryotic initiation factor 2α (Ser51) were determined by western immunoblotting. Tissue concentrations of the 4 AA studied responded linearly to media supply. Addition of Ile, Leu, Met, or Thr had no effect on eukaryotic initiation factor 2α phosphorylation. Isoleucine and Thr positively affected mTOR phosphorylation. However, the 2 AA had an antagonistic relationship. Similarly, Ile linearly increased ribosomal protein S6 phosphorylation, and Thr inhibited the Ile effect. In addition, eEF2 phosphorylation was linearly decreased by Ile and Leu. Threonine curvilinearly decreased eEF2 phosphorylation, Ile and Leu negatively interacted on eEF2, and Thr tended to inhibit Leu effects on eEF2. This work demonstrated saturable responses and interactions between AA on activation of the mTOR pathway. Incorporation of these concepts into milk protein response models will help to improve milk and milk protein yield predictions and increase postabsorptive N efficiency and reduce N excretion by dairy cows.

Broiler responses to reduced-protein diets supplemented with valine, isoleucine, glycine, and glutamic acid

SUMMARY Reduced performance is eventually observed when broilers are fed low-protein diets, even when industrial amino acids (AA) are provided to reach requirement levels. The reason for this detrimental effect has not been precisely determined, but it is possible that nonessential AA become limiting below a certain level of protein in the diet. The objective of this study was to evaluate the effects of Val, Ile, Gly, and Glu supplementation, individually or combined, in broiler diets with gradual reductions in protein. A total of 2,016 Ross × Ross 308 male broilers were fed 8 treatments with 9 replications (28 birds per pen) during a 42-d production period. overall care of birds complied with animal welfare directives from the Universidade Federal do Rio Grande do Sul. The control diet (treatment 1) was formulated without restricting CP, maintaining a Gly + Ser:Lys ratio of 155 or 158%. The other treatments, when not supplemented with l-Glu, had a CP content dependent on the fixed ratios of AA to Lys, generating diets with lower CP contents than the control diet. Treatment 2 was formulated with l-Val; treatment 3 with l-Val and Gly; treatment 4 with l-Val + l-Glu; treatment 5 with l-Val + Gly + l-Glu; treatment 6 with l-Val + l-Ile; treatment 7 with l-Val + l-Ile + Gly; and treatment 8 with l-Val + l-Ile + Gly + l-Glu. Dietary CP varied with feeding phase and treatment and reached 2.5% as the greatest reduction obtained. Supplementation of Gly and Glu improved BW gain and feed conversion. Benefits attributable to Gly supplementation were observed mainly in the early phases of growth. Conversely, broilers fed diets supplemented with Glu exhibited advantages in growth throughout experimentation. Addition of Ile, Glu, and Gly increased breast meat yield compared with broilers fed diets supplemented with only l-Val. Supplementation of Ile improved breast meat yield. Good broiler growth and meat yield can be obtained with Gly and Glu supplementation in reduced-CP diets, which implies a need for nitrogen for the synthesis of nonessential AA.

Isoleucine requirement of 80- to 120-kilogram barrows fed corn-soybean meal or corn-blood cell diets1,2,3

Six experiments were conducted to validate an Ile-deficient diet and determine the Ile requirement of 80- to 120-kg barrows. Experiment 1 had five replications, and Exp. 2 through 6 had four replications per treatment; all pen replicates had four crossbred barrows each (initial BW were 93, 83, 85, 81, 81, and 88 kg, respectively). All dietary additions were on an as-fed basis. In Exp. 1, pigs were fed a corn-soybean meal diet (C-SBM) or a corn-5% blood cell (BC) diet with or without 0.26% supplemental Ile (C-BC or C-BC+Ile) in a 28-d growth assay. On d 14, pigs receiving the C-BC diet were taken off experiment as a result of a severe decrease in ADFI. Growth performance did not differ for pigs fed C-SBM or C-BC + Ile (P = 0.36) over the 28-d experiment. In Exp. 2, pigs were fed the C-BC diet containing 0.24, 0.26, 0.28, 0.30, or 0.32% true ileal digestible (TD) Ile for 7 d in an attempt to estimate the Ile requirement using plasma urea N (PUN) as the response variable. Because of incremental increases in ADFI as TD Ile increased, PUN could not be used to estimate the Ile requirement. In Exp. 3, pigs were fed the C-BC diet containing 0.28, 0.30, 0.32, 0.34, or 0.36% TD Ile. Daily gain, ADFI, and G:F increased linearly (P < 0.01) as Ile increased in the diet. Even though there were no effects of TD Ile concentration on 10th rib fat depth or LM area, kilograms of lean increased linearly (P < 0.01) as TD Ile level increased. In Exp. 4, pigs were fed a C-SBM diet containing 0.26, 0.31, or 0.36% TD Ile. There were no differences in ADFI or ADG; however, G:F increased linearly (P = 0.02), with the response primarily attributable to the 0.31% Ile diet. In Exp. 5, pigs were fed 0.24, 0.27, 0.30, 0.33, or 0.36% TD Ile in a C-SBM diet. There were no differences in growth performance; however, average backfat, total fat, and percentage of fat increased quadratically (P < 0.10) with the addition of Ile. In Exp. 6, pigs were fed a 0.26% TD Ile C-SBM diet with or without crystalline Leu and Val to simulate the branched-chain AA balance of a C-BC diet. There were no differences in ADFI or ADG, but G:F increased (P = 0.09) when Leu and Val were added. In summary, the Ile deficiency of a C-BC diet can be corrected by the addition of Ile, and because ADFI was affected by Ile addition, the PUN method was not suitable for assessing the Ile requirement. The TD Ile requirement for 80- to 120-kg barrows for maximizing growth performance and kilograms of lean is not < 0.34% in a C-BC diet, but may be as low as 0.24% in a C-SBM diet.

Evaluation of Crude Protein Needs for Large White Male Turkeys from 16 to 20 Weeks of Age

A study was conducted to determine the minimum crude protein content of finisher diets based on corn and soybean meal supplemented with commercially available amino acids for male Large White turkeys. Diets were formulated to contain a minimum of 105% of NRC (1994) recommended levels of Met, Lys, TSAA, Thr, and Trp for diets fed 16 to 20 wk of age; no other essential amino acids were specified. The crude protein content of the diets ranged from 75 to 100% of the recommended level of 16.5%. When diets were formulated to contain at least the minimum recommended levels of Met, TSAA, Lys, Thr, reducing the crude protein content of the diet to less than 85% resulted in a significant reduction in weight at 20 wk or body weight gain from 16 to 20 wk. Addition of Ile and Val to diets formulated to contain 80 or 85% of the recommended crude protein level had no significant effect on body weight or weight gain, indicating that a deficiency of these amino acids per se was not responsible for the reduction in performance on diets with low levels of crude protein. Feed conversion was more variable and was not significantly influenced by dietary crude protein.

Effect of excess leucine in low protein diet on ketosis in 3-week-old male broiler chicks fed different levels of isoleucine and valine

A broiler study was designed to test whether or not the toxicity associated with high dietary Leu, is alleviated by the addition of Ile and Val; and if Leu toxicity is accompanied by ketosis. Dietary levels of 13.6 and 30.6 g Leu/kg, 8.3 and 11.6 g Ile/kg and 8.6 and 12.0 g Val/kg were used in a 2×2×2 factorial treatment arrangement with a complete randomized design. The isocaloric (ME=13.4 MJ/kg diet), and isonitrogenous (218 g crude protein/kg) diets were fed ad libitum to 1-week-old male broiler chicks for 14 days. Body weight gain, feed conversion, and β-OH butyrate level in plasma were determined at the end of the starter period. The diet based on 30.6 g Leu/kg in combination with the lower levels of Ile and Val reduced ( P<0.05) weight gain, cumulative feed intake, and feed conversion ratio by 90 and 76 g, and 0.065 points, respectively. A complete restoration of these criteria was obtained by increasing Ile and Val by 40% above their initial levels. β-OH butyrate levels in the plasma of birds receiving all the treatments were not significantly different and the grand mean value was 55 mg/l. The results indicated that high Leu in a low protein diet reduced the overall performance of young birds but failed to induce ketosis.

An approach to high-level production of a mecasermin (somatomedin C) fused protein in Escherichia coli HB101

A method to produce a mecasermin fused protein on an industrial scale was investigated. We constructed a new expression vector (designated pLSD1) derived from pLHSdMmtrp (Saito, Y. et al.: J. Biochem., 101, 123–134, 1987) by introduction of a synthetic fd phage terminator and deletion of the rop region originating from pBR322. The plasmid, pLSD1, exhibited high stability and was present at high copy number in Escherichia coli HB101. Although the growth of E. coli HB101 pLSD1 was not sufficient for high-level production of the fused protein in a Trp-deficient medium such as M9CA medium, it was improved by growing the strain in a medium containing 0.7% yeast extract which was constantly supplied with glucose. E. coli HB101 requires Pro and Leu for its growth; however, excess Leu tended to inhibit the cell growth. From the results of investigation of the mechanism of inhibition by Leu, addition of Ile was found to prevent the inhibition. Consequently, high-level production of the fused protein was attained by (i) using pLSD1 as the expression vector, (ii) cultivation of E. coli HB101 pLSD1 in a medium containing 0.7% yeast extract, (iii) fed-batch cultivation with periodic addition of glucose, and (iv) addition of Pro, Leu and Ile during cultivation. The cell density reached an OD at 600 nm of 50.4 and production of the fused protein was 1.24 g/ l broth in a 150 l fermentor.

Effect of Adding Branched-chain Amino Acids to a Nicotinic Acid-free, Low-protein Diet on the Conversion Ratio of Tryptophan to Nicotinamide in Rats

The effects of adding branched-chain amino acids to a nicotinic acid-free, low-protein diet on the conversion of tryptophan to nicotinamide were investigated in rats. The conversion ratio [urinary excretion of nicotinamide and its metabolites (μmol/day) × 100/tryptophan intake during urine collection (μmol/day)] was significantly lower in the groups fed with the 3% Leu-, Val-, or Ile-added diet than in the group fed with the control diet. Namely, the inhibition of this conversion was observed not only by the addition of Leu, but also by the addition of Val or Ile. The addition of Ile and/or Val to the Leu-added diet did not antagonize the Leu effect.

Performance of Commercial Laying Hens Fed Various Supplemental Amino Acids in a Corn-Soybean Meal Diet

Two experiments using Hy-Line® W36 pullets, 26 wk of age, helped determine their lysine (Lys) requirement and the next limiting amino acid in a corn-soybean diet. Corn-soybean meal diets ranging from 16.68 to 13.79% protein were fed in Experiment 1. All diets contained supplemental methionine (Met). The diets were fed with and without supplemental Lys. When unsupplemented diets were fed, Lys intake ranged from 754 to 502 mg/hen/day. The daily Lys requirement was 685.7, 677.4, and 755 mg/hen/day for egg mass (EM), egg production (EP), and egg weight (EW), respectively. When the diet provided less than 560 mg/hen/day of Lys, supplemental Lys did not restore EP. This finding indicated that another amino acid was limiting.In Experiment 2, various combinations of supplemental tryptophan (Trp), arginine (Arg), threonine (Thr), isoleucine (Ile), valine (Val), and glutamic acid (Glu) were fed. Hens receiving the negative control diet during 31-34 wk had daily intakes of 540, 505, 668, 395, 115, 426, 480, and 1968 mg/hen/day total sulfur amino acids (TSAA), Lys, Arg, Thr, Trp, Val, Ile, and Glu, respectively. Supplementing the diet with Met and Lys significantly increased EM. Further improvement in EM resulted from the combination of Thr, Arg, and Trp supplementation. The addition of Val to the diet with Met, Lys, Thr, Arg, and Trp significantly increased EM. However, the addition of Ile was without benefit in the presence or absence of Val. Egg mass was not significantly increased with a diet that contained all amino acids, with Val becoming next limiting after these. In a corn soybean meal diet Met is the first limiting EAA, followed by Lys. Trp and Arg are the next limiting, followed by Val.