Lysine Restriction Research Articles

Effect of Dietary Lysine Restriction and Energy Density on Performance, Nutrient Digestibility and Meat Quality in Finishing Pigs

This experiment evaluated the effects of dietary lysine restriction and energy density on growth performance, nutrient digestibility and meat quality of finishing pigs. A 2x2 factorial arrangement of treatments was utilized in a randomized complete block (RCB) design, and factor 1 was lysine restriction and factor 2 was energy density. The control diet was formulated to contain 3.265 Mcal of ME/kg, 0.75% lysine in the early-finishing phase and 3.265 Mcal of ME/kg, 0.60% lysine in the late-finishing phase and other nutrients met or exceeded NRC (1998) standards. Compared to the control diet (CON), lysine levels of experimental diets were restricted to 15% (treatment EL, EEL) or 30% (treatment ELL, EELL), whereas energy level of experimental diets was increased by 0.100 or 0.200 Mcal of ME/kg. A total of 100 crossbred pigs ([YorkshirexLandrace]×Duroc), with average initial body weight of 58.47±1.42 kg, were allotted to 5 dietary treatments based on sex and body weight. Each treatment had 5 replicates with 4 pigs (two barrows and two gilts) per pen. ADG, ADFI and feed efficiency were calculated in an 8-week growth trial. In the late finishing period (5-8 weeks), pigs fed ELL or EELL diets had decreased ADG and feed efficiency (p 0.05). In a metabolic trial, 15 pigs were used to evaluate the effect of dietary lysine restriction and energy density on nutrient digestibility. The digestibility of dry matter, crude fat and crude ash was not improved by restricting dietary lysine or energy density. However, crude protein digestibility was decreased (p<0.05) as dietary lysine was restricted. When dietary lysine was restricted, fecal nitrogen was increased whereas nitrogen retention was decreased. BUN concentration was affected by dietary lysine restriction; treatments ELL and EELL had higher BUN values than other treatments (p<0.01). Carcass characteristics and meat quality were measured when average body weight of pigs reached 107.83±1.50 kg. Treatment ELL had higher last rib backfat depth (p<0.05) than treatment CON, but ELL and EEL did not differ significantly. The ELL and EEL treatments had higher (p<0.05) subjective marbling score than treatment CON. Treatment EEL showed higher longissimus fat content than treatment EL and CON (p<0.01). The results indicated that finishing pigs fed a diet with 15% lysine restriction and 3.465 Mcal of ME/kg energy density had no detrimental effects on growth performance and N utilization, and could achieve substantial increases in marbling and longissimus fat content of pork.

Lysine restriction and realimentation affected growth, blood profiles and expression of genes related to protein and fat metabolism in weaned pigs

To investigate the effects of lysine restriction and subsequent realimentation on growth performance, blood profiles and gene expression of leptin and myostatin, 128 weaned pigs [initial body weight (BW) 6.96 ± 1.07 kg, 26 ± 2 days of age] were randomly allotted to four treatments. The starter diets during the first 2 weeks (P1) contained 100%, 80%, 70% or 60% of recommended lysine levels (National Research Council, 1998). Then, common grower 1 and 2 diets were offered for 2 weeks (P2 and P3) each. During P1, average daily gain (ADG) was linearly reduced (p < 0.05) with the increasing levels of lysine restriction. Growth rate was greater in pigs previously fed lysine-restricted diets than well-fed pigs although it did not reach a significant level during realimentation. However, the final BW and overall ADG were the lowest (p < 0.05) and F/G was poor in pigs fed 60% lysine diet. Relative visceral organ weights and composition of skeletal muscle were similar (p > 0.05) among the treatment. Blood triglyceride and glucose levels were increased (p < 0.05) during P1, while blood urine nitrogen, total protein and albumin levels were decreased (p < 0.05) during P2 with the reduction in dietary lysine levels. The abundance of myostatin mRNA in skeletal muscle and leptin mRNA in subcutaneous adipose tissue were lower (p < 0.05) in lysine-restricted pigs than in pigs fed non-restricted diets. In conclusion, 80% and 70% lysine restriction of starter diets resulted in inferior growth and compensatory growth effect was noted during realimentation, while 60% lysine restriction had a negative influence on growth performance. Moreover, the changes in myostatin and leptin mRNA abundance caused by nutritional manipulations may be involved in the regulation of protein and fat deposition in young pigs.

Effects of metabolizable energy and lysine restrictions on growth performance, blood profiles, and expression of myostatin and leptin genes in broilers

To investigate the effects of metabolizable energy and lysine restriction on performance, and gene expression of leptin and myostatin, three hundred twenty day-old Ross broiler chicks were randomly allotted to four treatments. Birds were subjected to their respective diets comprising two levels of ME (3200; 2880 kcal kg-1) and two levels of lysine (1.10; 0.88%) during days 8 to 21. The dietary crude protein levels were reduced with the proportion to the lysine levels, while ratios of essential amino acids relative to lysine were similar for all diets. During restriction, weight gain, breast muscle and abdominal fat yield were lower in birds fed lysine-restricted diets. Relative myostatin mRNA abundance was increased in breast muscle of lysine-restricted birds, while expression of leptin mRNA in abdominal fat was downregulated by energy and lysine restriction. During realimentation, birds previously fed with energy and/or lysine-restricted diets had comparable performance as birds fed unrestricted diets. At day 42, energy and lysine restriction increased relative myostatin mRNA expression in breast muscle and birds previously fed diet restricted in both energy and lysine had the highest relative myostatin mRNA expression (energy × lysine interaction, P &lt; 0.001). The relative leptin mRNA abundance was significantly lower in birds previously fed energy-restricted diets. These results indicated that early energy and lysine restriction from day 8 to 21 exhibited growth compensation during realimentation. In addition, myostatin and leptin mRNA expression in breast muscle and abdominal fat were modulated by nutritional treatments and were closely associated with changes in breast muscle yield and abdominal fat deposition. Key words: Metabolizable energy, lysine, myostatin, leptin, broiler

Lysine restriction during grower phase on growth performance, blood metabolites, carcass traits and pork quality in grower finisher pigs

The effects of lysine restriction during grower phase and realimentation during finisher phase on growth performance, nutrient digestibility, blood metabolites, carcass traits and pork quality were studied. Sixty-four pigs (two castrated males and two females per pen) weighing 34.34±5.22 kg were assigned to four dietary treatments. During grower (35–55 kg), pigs were fed isoenergetic lysine-restricted diets. The different lysine content of diets were 0.950 (NRC recommendation), 0.760, 0.665 and 0.570%, corresponding to lysine restriction of 20, 30 and 40%. Then all pigs were fed with common finisher 1 (55–85 kg) and 2 (85–115 kg) diets. Lysine restriction during the grower phase resulted in poor performance and lower concentration of blood metabolites but improved the nutrient digestibility and efficiency of lysine utilization. Compensatory growth response in terms of improved weight gain and feed efficiency was observed in pigs previously fed lysine-restricted diets during finisher 1, but the concentration of blood urea nitrogen and total protein were lower. No differences in growth performance, digestibility of nutrients and blood metabolites were noted during finisher 2. Lysine restriction of grower diets decreased the dressing percentage (quadratic, P=0.024), and protein content of longissimus muscle (linear P=0.034, and quadratic P=0.009). Thus, it could be concluded that pigs subjected to lysine restriction during grower phase exhibited compensatory growth responses in weight gain and improved efficiency of feed and lysine utilization for weight gain and lean accretion during finisher phase.

Lysine intake and neurotoxicity in glutaric aciduria type I: towards a rationale for therapy?

Glutaric aciduria type I (GA-I) is a rare cerebral organic acid disorder caused by inherited deficiency of glutaryl-CoA dehydrogenase (GCDH; EC 1.3.99.7), a mitochondrial flavoprotein catalysing the oxidative decarboxylation of glutaryl-CoA to crotonyl-CoA in the final catabolic pathways of the amino acids l-lysine, l-hydroxylysine and l-tryptophan (Goodman et al ., 1975). Biochemically, GA-I is characterized by an accumulation of the dicarboxylic acids glutaric acid (GA) and 3-hydroxyglutaric acid (3-OH-GA) as well as glutarylcarnitine (Baric et al ., 1999). Clinically, the disease course is complicated by striatal injury during an acute encephalopathic crisis, which is usually precipitated by a catabolic state (e.g. infectious diseases) in infancy or early childhood (Strauss et al ., 2003; Kolker et al ., 2006). If treated before the onset of irreversible neurological symptoms, the encephalopathic crises can be prevented in the majority of children (Strauss et al ., 2003; Naughten et al ., 2004; Kolker et al ., 2006). In particular, maintenance treatment with l-carnitine supplementation and lysine restriction is beneficial for pre-symptomatically diagnosed children (Kolker et al ., 2006). An animal model of GA-I has been developed to study pathophysiology. A detailed analysis of the histopathology, biochemistry, bioenergetics and behaviour of these mice has previously been published (Koeller et al ., 2002; Sauer et al ., 2005). In spite of high levels of GA and 3-OH-GA, these Gcdh−/− mice do not develop striatal degeneration either spontaneously or following a number of triggers, inducing a catabolic state (Koeller et al ., 2002), which contrasts with the association between catabolism and encephalopathic crises in GA-I patients. Recently, Zinnanti et al . reported in Brain (2006) that excessive dietary intake of lysine or protein produced a phenotype in Gcdh−/− mice that resembled some important clinical and neuroradiological …

The effect of dietary lysine restriction during the grower phase and subsequent dietary lysine concentration during the realimentation phase on the performance, carcass characteristics and nitrogen balance of growing–finishing pigs

Two experiments (exp.) were conducted to determine the effect of dietary lysine restriction during the grower phase and subsequent dietary lysine concentration during realimentation on the performance, carcass characteristics and nitrogen (N) balance of growing–finishing pigs. Seventy-two pairs of crossbred [meatline sires × (Large White × Landrace) dams] pigs (36 pairs entire male, 36 pairs female) were used in a 2 × 4 factorial performance study (exp. 1, 35 to 96 kg). The two factors were Diet1 (two lysine levels: LO or HI, day (d) 0 to 35) and Diet2 (four lysine levels: LO, M1, M2 and HI, d36 to slaughter). A further 30 boars were used in a 2 × 3 factorial N-balance study (exp. 2, 31 to 42 kg; Diet1: LO or HI; Diet2: LO, M3 and HI). The crude protein (CP) and lysine contents of the five isoenergetic (14.0 MJ DE/kg) diets were: LO (139 g/kg CP, 8.1 g lysine/kg), M1 (162 g/kg CP, 9.7 g lysine/kg), M2 (190 g/kg CP, 11.4 g lysine/kg), M3 (180 g/kg CP, 10.7 g lysine/kg) and HI (217 g/kg CP, 13.1 g lysine/kg). Diets were based on barley, wheat and soyabean meal with added vitamins, minerals and amino acids. Ratios of amino acids relative to lysine were similar for all diets. From d0 to 35 in exp. 1, pigs fed LO had lower daily gains (ADG: 785 vs. 939 g/day; P < 0.001), daily lysine intakes (DLYIN: 14.4 vs. 22.6 g/day; P < 0.001) and poorer feed conversion ratios (FCR: 2.28 vs. 1.84 kg/kg; P < 0.001) than pigs fed HI. From d36 to slaughter, pigs initially fed LO had higher ADG than those initially fed HI (948 vs. 879 g/day; P < 0.01). However, from d0 to slaughter, pigs initially fed LO had lower ADG (868 g/day; P < 0.01) and DLYIN (19.1 g/day; P < 0.001) than those fed HI (913 g/day and 23.3 g/day respectively). There was a Diet1 × Diet2 interaction for FCR from d36 to slaughter and d0 to slaughter ( P < 0.05). FCR of pigs previously fed LO improved with each increase in dietary lysine concentration up to 13.1 g/kg (HI), but improvement was only evident for lysine concentrations up to 11.4 g/kg (M2) for pigs previously fed HI. In exp. 2, Diet1 was fed for an initial 5-day collection period (after adjustment to crate; C1). Diet2 was then fed and immediately there were 2 successive 5-day collection periods (C2 and C3). A Diet1 × Time interaction ( P < 0.001) indicated that although N retention (NRET) during C1 was lower for pigs fed LO, there was no difference during C2 and C3 in NRET of pigs initially fed either LO or HI (14.5 vs. 25.0 g/day; 23.2 vs. 23.0 g/day; 26.0 vs. 26.6 g/day, for C1, C2 and C3, respectively). However, a similar interaction indicates that although N excretion (NEX) was 23% lower for LO compared with HI pigs during C1, there was no residual reduction in NEX of pigs initially fed LO ( P < 0.01: 8.9 vs. 11.6 g/day; 12.3 vs. 12.7 g/day; 13.8 vs. 14.0 g/day, for C1, C2 and C3, respectively). Exp. 1 indicated improved performance and an ability to respond positively to higher lysine concentrations during realimentation for previously restricted compared with unrestricted pigs, however, overall performance was reduced. However, exp. 2 indicated that although NRET of initially restricted pigs increased during realimentation, it did not surpass that of unrestricted pigs. This apparent discrepancy may have been due to the time period of the N balance study.

Neonatal Screening by Tandem Mass Spectrometry

After completing this article, readers should be able to: 1. List the major categories of diseases detectable by expanded newborn screening. 2. Give examples of the benefits and limitations of screening by tandem mass spectrometry. 3. Describe the appropriate follow-up for an abnormal screening result. The screening of newborns for inherited metabolic disorders is a well-established public health activity, first implemented in the early 1960s for the presymptomatic identification of patients who have phenylketonuria (PKU). Since then, significant technological advances, most importantly the development of tandem mass spectrometry (MS/MS), have enabled the detection of an increasing number of metabolic disorders in newborn blood. This article reviews the basic technology of MS/MS and its application to newborn screening, with the aim of highlighting the benefits and pointing out some limitations of this powerful technology. Early screening for PKU used the bacterial inhibition assay of Guthrie, in which inhibition of bacterial growth on an agar medium, introduced by the addition of a phenylalanine analog, was overcome by the presence of dried blood discs containing high levels of phenylalanine (such as from a PKU patient). This approach later was adapted for the detection of leucine in patients who have maple syrup urine disease (MSUD), methionine in patients who have classic homocystinuria, and tyrosine in patients who have tyrosinemia. Over the years, other techniques have been implemented to screen for additional disorders, including congenital hypothyroidism, biotinidase deficiency, galactosemia, hemoglobinopathies, and congenital adrenal hyperplasia. The classic criteria used to determine whether a disorder is suitable for screening include: 1) the disorder is clinically and biochemically well defined, 2) it is associated with significant morbidity or mortality, 3) an effective treatment is available, and 4) there is a simple and safe screening test. (1) By the early 1990s, all states offered screening for at least PKU and congenital hypothyroidism, …

Growth of the gastrointestinal tract in weaning pigs as affected by crude fibre content in the diet

1. Lysine restriction during grower phase on growth performance, blood metabolites, carcass traits and pork quality in grower finisher pigs Y. X. Yang, Z. Jin, S. Y. Yoon, J. Y. Choi, P. L. Shinde, X. S. Piao, B. W. Kim, S. J. Ohh, B. J. Chae Acta Agriculturae Scandinavica, Section A - Animal Science CrossRef

Physiological aspects of compensatory growth in pigs

1. Lysine restriction and realimentation affected growth, blood profiles and expression of genes related to protein and fat metabolism in weaned pigs Y. X. Yang, J. Guo, Z. Jin, S. Y. Yoon, J. Y. Choi, M. H. Wang, X. S. Piao, B. W. Kim, B. J. Chae Journal of Animal Physiology and Animal Nutrition CrossRef

Aging Increases N epsilon -(Carboxymethyl)lysine and Caloric Restriction Decreases N epsilon -(Carboxyethyl)lysine and N epsilon -(Malondialdehyde)lysine in Rat Heart Mitochondrial Proteins

The present investigation studies the effect of aging, short-term and long-term caloric restriction on four different markers of oxidative, glycoxidative or lipoxidative damage to heart mitochondrial proteins: protein carbonyls (measured by ELISA); N epsilon -(carboxyethyl)lysine (CEL), N epsilon -(carboxymethyl)lysine (CML), and N epsilon -(malondialdehyde)lysine (MDA-lys) measured by gas chromatography/mass spectrometry. Aging increased the steady state level of CML in rat heart mitochondria without changing the levels of the other three markers of protein damage. Short-term caloric restriction (six weeks) did not change any of the parameters measured. However, long-term (one year) caloric restriction decreased CEL and MDA-lys in heart mitochondria and did not change protein carbonyls and CML levels. The decrease in MDA-lys was not due to changes in the sensitivity of mitochondrial lipids to peroxidation since the measurements of the fatty acid composition showed that the total number of fatty acid double bonds was not changed by caloric restriction. The decrease in CEL and MDA-lys in caloric restriction agrees with the previously and consistently described finding that caloric restriction agrees with the previously and consistently described finding that caloric restriction lowers the rate of generation of reactive oxygen species (ROS) in rodent heart mitochondria, although in the case of CEL a caloric restriction-induced lowering of glycaemia can also be involved. The CEL and MDA-lys results support the notion that caloric restriction decreases oxidative stress-derived damage to heart mitochondrial proteins.

Nutrition support for glutaric acidemia type I

Glutaric acidemia type I is a rare, autosomal recessive, inborn error of lysine and tryptophan metabolism. This disorder is caused by a defect in the mitochondrial enzyme glutaryl-coenzyme A dehydrogenase, resulting in permanent or episodic elevations of glutaric acid. Despite clinical variability, untreated children often experience progressive neurologic damage that frequently leads to death. Recent evidence suggests that a lysine- and tryptophan-restricted diet and pharmacologic therapy with oral riboflavin and l-carnitine may arrest the neurologic deterioration. Several cases of normal growth and development have been reported in children diagnosed and treated before neurologic insult. In this article, we review previously published experience with dietary and pharmacologic therapy and provide guidelines for nutrition support based on our experience of treating four affected children. We suggest that dietary restriction of lysine and tryptophan is a safe and potentially effective therapy for individuals with glutaric acidemia type I.

Effect of method and phase of nutrient restriction during rearing on productive performance of light hybrid pullets and hens

1. An experiment was conducted to study the effect of method (low-lysine or quantity of food) and phase (starter or grower) of restriction during rearing on growth and laying performance in Leghorn hybrids. 2. A reduction in body weight gain was achieved by feeding pullets a low-lysine diet in either the starter phase (0-6 weeks of age: 4.0 g/kg digestible lysine) or the grower phase (7-18 weeks of age: 3.0 g/kg digestible lysine). 3. In each phase, the lysine restriction was compared with a daily food restriction, in which pullets received a quantity of food sufficient to pair-gain with their lysine-restricted counterparts. 4. The delay in onset of production was greatest in the lysine-restricted birds, for both phases of restriction. 5. Hens restricted during the grower phase laid heavier eggs than those restricted during the starter phase, despite having similar body weights at end of rearing. This effect was not influenced by the restriction method. 6. Production traits varied between pullets reared on different feeding strategies up to similar body weights at 18 weeks and onwards. It is concluded that body weight is not the only factor determining laying performance.

Combined effect of dimethylnitrosamine and a lysine-restricted diet on O6-methylguanine-DNA methyltransferase levels in mouse tissues

O6-Methylguanine is a lesion produced in DNA after exposure of animals to the procarcinogen dimethylnitrosamine. The lesion may lead to mutagenesis or carcinogenesis if not repaired. Repair is accomplished by the protein O6-methylguanine-DNA methyltransferase (MT). The methyl group is transferred to a cysteine residue of the protein, which is not regenerated. In mice, after exposure to alkylating agents, the synthesis of the protein is non-inducible. The inactivation of MT as a result of the transmethylation makes new synthesis of the protein molecules necessary for further dealkylation reactions. Protein synthesis activity correlates well with dietary protein quality. Nutritional conditions of amino acid restriction will limit the number of MT molecules synthesized. Continuous exposure of mice to dimethylnitrosamine will further diminish the pool of the protein.In this study, mice were fed a diet low in lysine and simultaneously given dimethylnitrosamine in the drinking water at concentrations resulting in dosages of zero, 0.4 mg or 1.2 mg/kg body weight/day. After 6 days MT was assayed in liver, kidney and lung. In liver and kidney, lysine restriction provoked a decrease in MT levels per mg of tissue DNA which was intensified by the presence of dimethylnitrosamine in the drinking water. Recovery from lysine restriction with respect to MT levels was achieved within 2 days. In lung, moderate effects on MT levels were observed when dietary lysine restriction was combined with the highest dosage of dimethylnitrosamine used (1.2 mg/kg body weight/day).The data strongly emphasize the importance of an adequate amino acid mixture in the diet, to support protein synthesis and to allow for high MT levels and repair of DNA lesions at the O-6 position of guanine during the exposure of the animals to alkylating agents.