scholarly journals Response in hepatic removal of amino acids by the sheep to short-term infusions of varied amounts of an amino acid mixture into the mesenteric vein

2001 ◽  
Vol 85 (6) ◽  
pp. 689-698 ◽  
Author(s):  
G. E. Lobley ◽  
D. M. Bremner ◽  
D. S. Brown
Keyword(s):  
Amino Acids ◽  
Digestive Tract ◽  
Basal Diet ◽  
Acid Mixture ◽  
Hepatic Transport ◽  
Total Blood ◽  
Isoleucine Leucine ◽  
Mesenteric Vein ◽  
Wide Range ◽  
Branched Chain

Under conditions of chronic supply the liver removes most amino acids (AA) in excess of net anabolic needs. Little information is available, however, on how acute alterations in AA supply (as might occur with once-daily feeding regimens) are controlled by the liver. Are these also extracted completely in a ‘first-pass’ manner or are there limitations to hepatic uptake? Furthermore, is the rate of removal ‘saturable’ (by Michaelis–Menten kinetics) over the range of supply experienced under normal feeding conditions? These questions have been addressed in a study that involved acute (4.5 h) increases in AA supply. Four sheep were prepared with trans-hepatic vascular catheters and were offered a basal diet (equivalent to 1.6×energy maintenance) throughout. On four occasions, at 7 d intervals, they were infused with various amounts of an AA mixture into the mesenteric vein over a 4.5 h period. The mixture contained fourteen AA in the proportions present in rumen microbial protein. The amounts infused were calculated to provide an additional one, two, three and four times that absorbed from the basal diet. Continuous blood collections were removed over 2 h intervals before (basal diet only) and at 0.5–2.5 and 2.5–4.5 h of AA infusion. Transfers of AA, from the digestive tract and to the liver, were calculated for both plasma and total blood. The recovery of the infused AA across the portal-drained viscera (PDV) was quantitative (100%) only for histidine and proline, the remaining AA were recovered at 56–83 %. These losses correlated (P<0.001) with the arterial concentrations and were probably due to removal of AA from the systemic circulation by the tissues of the digestive tract. Despite the wide range of net PDV appearances (i.e. absorbed plus infused), the percentage of most AA removed by the liver remained constant, but the percentage varied with AA (from 34 for proline to 78 for tryptophan for blood transfers). Thus, even when supply was increased 5-fold over baseline there was no indication that the transport into the liver declined, indeed the absolute removals continued to increase. In contrast, the branched-chain AA (isoleucine, leucine and valine) did not exhibit constant percentage extractions. Their percentage extractions were always the lowest (16, 10 and 25 respectively) and tended to decline at the highest infusion rates, indicative of saturation in hepatic transport and/or metabolism. The arterial concentrations of all infused AA increased (P<0.001) with rate of infusion, again indicative that the liver did not extract all the net AA available across the PDV. Absolute amounts removed were similar between plasma and blood, indicating that most of the hepatic transfers occurred from plasma. The fractional rates of transfer from total inflow to the liver (i.e. with re-circulated AA included) were 3- to 4-fold lower than rates based on the amounts absorbed plus infused. The highest percentage extraction for total blood inflows was for serine (27), but most were between 6 and 16, except for the branched-chain AA, which were all <1. Use of percentage extractions based on total inflows are probably more appropriate for development of mathematical models of liver metabolism, and the current data suggest that constant values may be applied. The needs of the liver for specific mechanisms involving phenylalanine and histidine (plasma protein synthesis), glycine (detoxification of xenobiotics) and alanine (gluconeogenesis) probably also require to be included in such models.

scholarly journals Effects of Fermentation on Standardized Ileal Digestibility of Amino Acids and Apparent Metabolizable Energy in Rapeseed Meal Fed to Broiler Chickens

Animals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1774
Author(s):  
Zhengke Wu ◽  
Jiao Liu ◽  
Jiang Chen ◽  
Shoaib Ahmed Pirzado ◽  
Yang Li ◽  
...  
Keyword(s):  
Amino Acids ◽  
Broiler Chickens ◽  
Nutritive Value ◽  
Animal Feed ◽  
Basal Diet ◽  
Rapeseed Meal ◽  
Metabolizable Energy ◽  
Isoleucine Leucine ◽  
Ileal Digestibility ◽  
Apparent Metabolizable Energy

Rapeseed meal (RSM) is a common protein ingredient in animal diets, while the proportion of RSM in diets is limited because of its anti-nutritional factors. Fermentation based on mixed microbial strains appears to be a suitable approach to improve the nutritive value of rapeseed meal in animal feed. In this study, we evaluated the effects of fermentation on the apparent metabolizable energy (AME) values and standardized ileal digestibility (SID) of amino acids in RSM fed broilers. The AME and nitrogen-corrected apparent metabolizable energy (AMEn) values of RSM and fermented rapeseed meal (FRSM) were determined by the substitution method, with RSM and FRSM proportionally replacing the energy-yielding components of the basal diet by 30%. Results show that fermentation improved AME and AMEn of RSM from 7.44 to 8.51 MJ/kg and from 7.17 to 8.26 MJ/kg, respectively. In the second experiment, two experimental diets were formulated, with RSM and FRSM being the sole sources of amino acids. A nitrogen-free diet (NFD) was also formulated to determine endogenous amino acids losses (EAAL). Feeding on FRSM resulted in higher (p < 0.05) apparent ileal digestibility (AID) and SID of alanine, valine, isoleucine, leucine, tyrosine, lysine, arginine, and phenylalanine. No significant differences between RSM and FRSM were found for AID and SID of asparagine, histidine, threonine, serine, glutamine, praline, glycine, methionine, and cystine. FRSM had greater AMEn values and SID of amino acids compared to RSM, therefore, FRSM was nutritionally superior to RSM in broiler diets.

scholarly journals Mechanisms of the Pellagragenic Effect of Leucine: Stimulation of Hepatic Tryptophan Oxidation by Administration of Branched-Chain Amino Acids to Healthy Human Volunteers and the Role of Plasma Free Tryptophan and Total Kynurenines

2014 ◽  
Vol 7 ◽  
pp. IJTR.S18231 ◽  
Author(s):  
Abdulla A-B Badawy ◽  
Sarah L. Lake ◽  
Donald M. Dougherty
Keyword(s):  
Amino Acids ◽  
Hepatic Uptake ◽  
Branched Chain Amino Acids ◽  
Amino Acid Mixture ◽  
Kynurenine Pathway ◽  
Acid Mixture ◽  
Healthy Human ◽  
Free Tryptophan ◽  
Tryptophan Oxidation ◽  
Branched Chain

The pellagragenic effect of leucine (Leu) has been proposed to involve modulation of L-tryptophan (Trp) metabolism along the hepatic kynurenine pathway. Here, we discuss some of the mechanisms suggested and report the effects in healthy volunteers of single doses of Leu (4.05–6.75 g) administered in a 16-amino acid mixture on concentrations of plasma Trp and its kynurenine metabolites. Flux of Trp through Trp 2,3-dioxygenase (TDO) is dose-dependently enhanced most probably by Leu and can be attributed to TDO activation. Trp oxidation is better expressed using plasma total kynurenines, rather than kynurenine, and free, rather than total, Trp. Increased hepatic Trp oxidation may be an additional mechanism of action of branched-chain amino acids in the acute Trp depletion test. Inhibition of intestinal absorption or hepatic uptake of Trp by Leu can be excluded. Potential mechanisms of the aggravation of pellagra symptoms by Leu are discussed.

Bootstrapped neural network models for analyzing the responses of broiler chicks to dietary protein and branched chain amino acids

2014 ◽  
Vol 94 (1) ◽  
pp. 79-85 ◽  
Author(s):  
A. Faridi ◽  
A. Golian ◽  
A. Heravi Mousavi ◽  
J. France
Keyword(s):  
Neural Network ◽  
Amino Acids ◽  
Dietary Protein ◽  
Average Daily Gain ◽  
Network Models ◽  
Branched Chain Amino Acids ◽  
Broiler Chicks ◽  
Neural Network Models ◽  
Isoleucine Leucine ◽  
Branched Chain

Faridi, A., Golian, A., Heravi Mousavi, A. and France, J. 2014. Bootstrapped neural network models for analyzing the responses of broiler chicks to dietary protein and branched chain amino acids. Can. J. Anim. Sci. 94: 79–85. Reliable prediction of avian responses to dietary nutrients is essential for planning, management, and optimization activities in poultry nutrition. In this study, two bootstrapped neural network (BNN) models, each containing 100 separated neural networks (SNN), were developed for predicting average daily gain (ADG) and feed efficiency (FE) of broiler chicks in response to intake of protein and branched chain amino acids (BCAA) in the starter period. Using a re-sampling method, 100 different batches of data were generated for both the ADG and FE sets. Starting with 270 data lines extracted from eight studies in the literature, SNN models were trained, tested, and validated with 136, 67, and 67 data lines, respectively. All 200 SNN models developed, along with their respective BNN ones, were subjected to optimization (to find the optimum dietary protein and BCAA levels that maximize ADG and FE). Statistical analysis indicated that based on R 2, the BNN models were more accurate in 76 and 56 cases (out of 100) compared with the SNN models developed for ADG and FE, respectively. Optimization of the BNN models showed protein, isoleucine, leucine, and valine requirements for maximum ADG were 231.80, 9.05, 14.03 and 10.90 g kg−1 of diet, respectively. Also, maximum FE was obtained when the diet contained 232.30, 9.07, 14.50, and 11.04 g kg−1 of protein, isoleucine, leucine, and valine, respectively. The results of this study suggest that in meta-analytic modelling, bootstrap re-sampling algorithms should be used to better analyze available data and thereby take full advantage of them. This issue is of importance in the animal sciences as producing reliable data is both expensive and time-consuming.

scholarly journals Effects on nitrogen balance and metabolism of branched-chain amino acids by growing pigs of supplementing isoleucine and valine to diets with adequate or excess concentrations of dietary leucine

2020 ◽  
Vol 98 (11) ◽  
Author(s):  
Woong B Kwon ◽  
Jose A Soto ◽  
Hans H Stein
Keyword(s):  
Amino Acids ◽  
Plasma Concentration ◽  
Plasma Concentrations ◽  
Basal Diet ◽  
Branched Chain Amino Acids ◽  
Growing Pigs ◽  
Plasma Urea ◽  
N Retention ◽  
Branched Chain ◽  
Dietary Treatments

Abstract Diets based on high levels of corn protein have elevated concentrations of Leu, which may negatively affect N retention in pigs. An experiment was, therefore, conducted to test the hypothesis that Ile and Val supplementation may overcome the detrimental effects of excess dietary Leu on N balance and metabolism of branched-chain amino acids (BCAA) in growing pigs. A total of 144 barrows (initial body weight: 28.5 kg) were housed in metabolism crates and randomly assigned to 1 of 18 dietary treatments. The basal diet contained 0.98% standardized ileal digestible (SID) Lys and had SID Leu, Val, and Ile ratios to SID Lys of 100%, 60%, and 43%, respectively. Crystalline l-Leu (0% or 2.0%), l-Ile (0%, 0.1%, or 0.2%), and l-Val (0%, 0.1%, or 0.2%) were added to the basal diet resulting in a total of 18 dietary treatments that were arranged in a 2 × 3 × 3 factorial. Urine and fecal samples were collected for 5 d after 7 d of adaptation. Blood, skeletal muscle, and liver samples were collected at the conclusion of the experiment. There were no three-way interactions among the main effects. Excess Leu in diets reduced (P &lt; 0.05) N retention and biological value of protein and increased (P &lt; 0.001) plasma urea N (PUN), but PUN was reduced (P &lt; 0.05) as dietary Val increased. Concentrations of Leu in the liver were greater (P &lt; 0.001) in pigs fed excess Leu diets than in pigs fed adequate Leu diets, but concentrations of BCAA in muscle were greater (P &lt; 0.05) in pigs fed low-Leu diets. Increasing dietary Ile increased (P &lt; 0.001) plasma-free Ile and plasma concentration of the Ile metabolite, α-keto-β-methylvalerate, but the increase was greater in diets without excess Leu than in diets with excess Leu (interaction, P &lt; 0.001). Plasma concentrations of Val and the Val metabolite α-keto isovalerate increased (P &lt; 0.001) with increasing dietary Val in diets with adequate Leu, but not in diets with excess Leu (interaction, P &lt; 0.001). Increasing dietary Leu increased (P &lt; 0.001) plasma-free Leu and plasma concentration of the Leu metabolite, α-keto isocaproate (KIC). In contrast, increased dietary Val reduced (P &lt; 0.05) the plasma concentration of KIC. In conclusion, excess dietary Leu reduced N retention and increased PUN in growing pigs, but Val supplementation to excess Leu diets may increase the efficiency of amino acid utilization for protein synthesis as indicated by reduced PUN.

scholarly journals The ilvGMEDA Operon Is Regulated by Transcription Attenuation in Vibrio alginolyticus ZJ-T

2019 ◽  
Vol 85 (19) ◽  
Author(s):  
Yiqin Deng ◽  
Xing Luo ◽  
Mei Xie ◽  
Philippe Bouloc ◽  
Chang Chen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Amino Acids ◽  
Branched Chain Amino Acids ◽  
Vibrio Alginolyticus ◽  
Gram Negative ◽  
Content Type ◽  
Wide Range ◽  
Transcription Attenuation ◽  
Branched Chain ◽  
Fish And Shellfish

ABSTRACT Bacteria synthesize amino acids according to their availability in the environment or, in the case of pathogens, within the host. We explored the regulation of the biosynthesis of branched-chain amino acids (BCAAs) (l-leucine, l-valine, and l-isoleucine) in Vibrio alginolyticus, a marine fish and shellfish pathogen and an emerging opportunistic human pathogen. In this species, the ilvGMEDA operon encodes the main pathway for biosynthesis of BCAAs. Its upstream regulatory region shows no sequence similarity to the corresponding region in Escherichia coli or other Enterobacteriaceae, and yet we show that this operon is regulated by transcription attenuation. The translation of a BCAA-rich peptide encoded upstream of the structural genes provides an adaptive response similar to the E. coli canonical model. This study of a nonmodel Gram-negative organism highlights the mechanistic conservation of transcription attenuation despite the absence of primary sequence conservation. IMPORTANCE This study analyzes the regulation of the biosynthesis of branched-chain amino acids (leucine, valine, and isoleucine) in Vibrio alginolyticus, a marine bacterium that is pathogenic to fish and humans. The results highlight the conservation of the main regulatory mechanism with that of the enterobacterium Escherichia coli, suggesting that such a mechanism appeared early during the evolution of Gram-negative bacteria, allowing adaptation to a wide range of environments.

Abstract 048: Circulating Branched-Chain Amino Acids and Incident Cardiovascular Disease in a Prospective Cohort of US Women

Circulation ◽  
2018 ◽  
Vol 137 (suppl_1) ◽  
Author(s):  
Deirdre K Tobias ◽  
Patrick R Lawler ◽  
Paulo H Harada ◽  
Olga V Demler ◽  
Paul M Ridker ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Cardiovascular Disease ◽  
Amino Acids ◽  
Prospective Cohort ◽  
Branched Chain Amino Acids ◽  
Health Study ◽  
Blood Collection ◽  
Cvd Risk ◽  
Isoleucine Leucine ◽  
Branched Chain

Introduction: Recent metabolomics studies have identified circulating levels of branched-chain amino acids (BCAAs; isoleucine, leucine, valine) as strong predictors of type 2 diabetes (T2D). Whether BCAAs are implicated in cardiovascular disease (CVD) risk has not been established. Hypothesis: We hypothesized that higher baseline levels of plasma BCAAs are associated with an elevated risk of incident CVD events, and evaluated whether this relationship was dependent on an intermediate diagnosis of T2D. Methods: Participants enrolled in the Women’s Health Study prospective cohort were eligible if they did not report CVD or cancer prior to baseline blood collection (N=27,172, mean baseline age=54.7 years). Plasma BCAA metabolites were measured via proton NMR spectroscopy, ln-transformed, and standardized for analysis. We used multivariable Cox proportional regression models to estimate hazard ratios (HR) and 95% confidence intervals (CI) per standard deviation (SD) of total and individual BCAAs with incident CVD (myocardial infarction [MI], stroke, coronary revascularization). Results: 1,917 confirmed CVD events occurred over follow-up (mean 18.6 years). In models adjusted for age, body mass index, smoking status, diet quality, physical activity, and other established CVD risk factors, total BCAAs were positively associated with CVD (per SD, HR=1.13, CI=1.08 to 1.19), comparable in magnitude to the association of LDL cholesterol with CVD (per SD, HR=1.15, CI=1.09 to 1.21). In particular, BCAAs were associated with coronary events (MI: HR=1.21, CI=1.10 to 1.33; revascularization: HR=1.15, CI=1.07 to 1.23), but not with stroke (HR=1.07, CI=0.98 to 1.15). The BCAA-CVD relationship was notably greater (p-interaction=0.008) among participants who developed T2D prior to a CVD event (HR=1.25, CI=1.13 to 1.39), vs. women without T2D (HR=1.07, CI=1.01 to 1.13). Isoleucine, leucine, and valine were each associated with CVD (p<0.05). Further adjusting for biomarkers of potential intermediates, HbA1c, lipids, and a lipoprotein-based insulin resistance score entirely eliminated the associations of BCAAs with CVD. Conclusions: Circulating plasma BCAAs were positively associated with long-term incident CVD in a cohort of US women, in particular among women who developed T2D prior to a CVD event. Impaired BCAA metabolism may represent a shared pathway of insulin resistance that links the risks of T2D and CVD.

scholarly journals Effect of leucine on intestinal absorption of tryptophan in rats

1985 ◽  
Vol 54 (3) ◽  
pp. 695-703 ◽  
Author(s):  
Chisae Umezawa ◽  
Yuko Maeda ◽  
Kanji Haba ◽  
Mariko Shin ◽  
Keiji Sano
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Intestinal Absorption ◽  
Digestive Tract ◽  
Causal Relation ◽  
Control Diet ◽  
Essential Amino Acids ◽  
Amino Acid Mixture ◽  
Side Chain ◽  
Acid Mixture

1. To elucidate the causal relation between leucine and the lowering of hepatic NAD content of rats fed on a leucine-excessive diet (Yamada et al. 1979), the effect of leucine on intestinal absorption of tryptophan was investigated.2. Co-administration of [3H]tryptophan and leucine, with leucine at ten times the level of tryptophan, delayed absorption of L-[side chain 2,3-3H]tryptophan from the digestive tract and incorporation of [3H]tryptophan into portal blood, the liver and a protein fraction of the liver. After 120 min, more than 95% of tryptophan was absorbed whether [3H]tryptophan was administered with or without leucine.3. Co-administration of a mixture of ten essential amino acids, in proportions simulating casein, with [3H]tryptophan markedly delayed absorption of tryptophan from the digestive tract. The addition of supplementary leucine to the amino acid mixture, however, caused no further delay.4. In rats prefed a leucine-excessive diet for 1 week [3H]tryptophan was absorbed at the same rate as in rats fed on a control diet.5. The results indicate that competition between tryptophan and leucine for intestinal absorption did not cause lowering of hepatic NAD.

scholarly journals Association of Dietary Branched-Chain Amino Acids With Obesity: The Filipino Women's Diet and Health Study (FiLWHEL)

2021 ◽  
Vol 5 (Supplement_2) ◽  
pp. 1072-1072
Author(s):  
Akinkunmi Okekunle ◽  
Heejin Lee ◽  
Sherlyn Mae Provido ◽  
Grace Chung ◽  
Sangmo Hong ◽  
...  
Keyword(s):  
Amino Acids ◽  
Statistical Significance ◽  
Branched Chain Amino Acids ◽  
Health Study ◽  
Dietary Intakes ◽  
Obesity Risk ◽  
Isoleucine Leucine ◽  
Dietary Recall ◽  
Filipino Migrants ◽  
Branched Chain

Abstract Objectives Migration plays a significant role in dietary choices and health of populations. Studies on dietary intakes of branched-chain amino acids (BCAA) and health status of migrant populations are scarce. This study examined the association between dietary BCAA intake and risk of obesity among migrant Filipino women in Korea. Methods This study included 428 women (20–57years) enrolled in the FiLWHEL study. Demographic information and anthropometric measurements (weight and height) were obtained using a standard protocol. Dietary BCAA (isoleucine, leucine, and valine) intakes were derived from a one-day 24-hour dietary recall. Body mass index (BMI) was calculated from weight and height. Obesity was defined as BMI ≥ 25 kg/m2. Energy-adjusted BCAA intakes were categorized in quartile distribution with the lowest quartile as a reference and multivariable-adjusted odds ratio (OR) with 95% confidence interval (CI) of obesity risk were estimated using logistic regression at a statistical significance of P &lt; 0.05. Results Mean age and BMI were 35.0 ± 8.1 years and 23.6 ± 3.9 kg/m2 respectively. 30.8% had BMI ≥ 25 kg/m2. Also, median and interquartile range of BCAA intakes (mg/day) were isoleucine: 1920.9 (1231.9–2719.1), leucine: 3318.9 (2134.2–4774.1), valine: 2257.3 (1442.6–3283.1) and total BCAA: 7519.0 (4762.0–10,726.9). Multivariable-adjusted OR and 95% CI for obesity risk given dietary BCAA intakes for each subsequent quartile compared to the bottom quartile were; isoleucine: 0.48 (0.27–0.89), 0.67 (0.37–1.02), and 0.49 (0.27–0.89) P for trend = 0.09; leucine: 0.69 (0.37–1.28), 0.80 (0.44–1.46), and 0.62 (0.34–1.13) P for trend = 0.23; valine: 0.51 (0.27–0.95), 0.77 (0.43–1.37), and 0.52 (0.28–0.95) P for trend = 0.15 and total BCAA: 0.58 (0.31–1.09), 0.82 (0.45–1.48), and 0.56 (0.31–1.03) P for trend = 0.23. Conclusions Dietary BCAA intake appears inversely related to the odds of obesity in this sample of Filipino migrants in Korea. Cohort studies among migrant population might significantly benefit the validation of these observations. Funding Sources This work was supported by the Hanmi Pharmaceutical Co., Ltd, (No. 201300000001270), Chong Kun Dang Pharm. Seoul, Korea (No. 201600000000225) and the Brain Pool Program through the National Research Foundation of Korea funded by the Ministry of Science and ICT (No. 2020H1D3A1A04081265).

scholarly journals The Relationship between S. aureus and Branched-Chain Amino Acids Content in Composite Cow Milk

Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 981 ◽  
Author(s):  
L. Grispoldi ◽  
M. Karama ◽  
F. Ianni ◽  
A. La Mantia ◽  
L. Pucciarini ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid Content ◽  
Branched Chain Amino Acids ◽  
Cow Milk ◽  
Total Amino Acid ◽  
Phase Method ◽  
Microbiological Analysis ◽  
Isoleucine Leucine ◽  
Milk Samples ◽  
Branched Chain

The early diagnosis of mastitis is an essential factor for the prompt detection of the animal for further actions. In fact, if not culled, infected cows must be segregated from the milking herd and milked last, or milked with separate milking units. Besides microbiological analysis, the somatic cell count (SCC) commonly used as predictor of intramammary infection, frequently lead to a misclassification of milk samples. To overcome these limitations, more specific biomarkers are continuously evaluated. The total amino acid content increases significantly in mastitic milk compared to normal milk. S. aureus requires branched-chain amino acids (BCAAs—isoleucine, leucine, and valine) for protein synthesis, branched-chain fatty acids synthesis, and environmental adaptation by responding to their availability via transcriptional regulators. The increase of BCAAs in composite milk has been postulated to be linked to mammary infection by S. aureus. The aim of this work is to demonstrate, by a direct ion-pairing reversed-phase method, based on the use of the evaporative light-scattering detector (IP-RP-HPLC-ELSD), applied to 65 composite cow milk samples, a correlation between the concentration of isoleucine and leucine, and S. aureus load. The correlation coefficient, r, was found to be 0.102 for SCC (p = 0.096), 0.622 for isoleucine (p < 0.0001), 0.586 for leucine (p < 0.0001), 0.013 for valine (p = 0.381), and 0.07 for tyrosine (p = 0.034), standing for a positive correlation between S. aureus and isoleucine and leucine concentration. The link between the content of BCAAs, isoleucine and leucine, and udder infection by S. aureus demonstrated with our study has an important clinical value for the rapid diagnosis of S. aureus mastitis in cows.

THE SIGNIFICANCE OF SILAGE PROTEIN DEGRADATION AND PLASMA AMINO ACID RATIOS IN THE CONTROL OF FOOD INTAKE BY LAMBS FED ENSILED AND FRESH ALFALFA

1986 ◽  
Vol 66 (4) ◽  
pp. 1029-1038 ◽  
Author(s):  
D. A. FLORES ◽  
L. E. PHILLIP ◽  
D. M. VEIRA ◽  
M. IVAN
Keyword(s):  
Amino Acids ◽  
Food Intake ◽  
Dry Matter ◽  
Nitrogen Retention ◽  
Essential Amino Acids ◽  
Isoleucine Leucine ◽  
Fresh Frozen ◽  
The Difference ◽  
Branched Chain ◽  
Particle Length

Alfalfa (30% dry matter) was harvested with a particle length of 0.6 cm, conserved fresh (frozen) or as silage and fed to eight lambs during two 27-d periods. The ensiling process resulted in substantial degradation of lysine, threonine, histidine, arginine, tryptophan and tyrosine in the original herbage. Isoleucine, leucine and valine resisted degradation during ensilage. As a consequence of these changes, the ratios of tyrosine: large neutral amino acids and tyrosine: phenylalanine (TYR:LNAA and TYR:PHE) were markedly lower in ensiled compared to fresh alfalfa (0.035 vs. 0.051 and 0.235 vs. 0.313, respectively) but these ratios in plasma were higher (P < 0.05) with silage than with fresh forage (0.114 vs. 0.095 and 1.020 vs. 0.997). Ensiling of alfalfa resulted in a 19% reduction in silage intake but the response did not correlate with changes in plasma ratios of TYR:LNAA and TYR:PHE. Nitrogen retention was 27% lower with ensiled than with fresh alfalfa. Plasma levels of branched chain and other essential amino acids tended to be higher with fresh than ensiled forage but the difference was not significant. It is concluded that the reduction in food intake with alfalfa silage was unrelated to changes in specific ratios of amino acids in plasma but could be related to the supply of essential amino acids to the intestine of lambs. Key words: Silage intake, lambs, nitrogen balance, plasma amino acids, alfalfa

Sign in / Sign up

Export Citation Format

Share Document