Dietary Lysine Supplementation Research Articles

Dietary supplementation of methionine, lysine, and tryptophan as possible modulators of growth, immune response, and disease resistance in striped catfish (Pangasius hypophthalmus).

The present study investigated the potential role of different essential amino acids (AA) in striped catfish (Pangasius hypophthalmus). Fish (initial weight = 17.91±0.27 g, n = 260) were fed with eight isonitrogenous (30%), and isolipidic diets (6%) formulated to include different combinations of tryptophan (Trp), methionine (Met), and lysine (Lys) (T0: Zero AA, T1: Trp, T2: Lys, T3: Met, T4: Trp+Met, T5: Lys+Trp, T6: Met+Lys, T7: Lys+Trp+Met) for eight weeks. The dose of amino acid supplementation, whether individually or in combination, was 5g of each amino acid per kg of diet. The trial comprised eight treatments, with each treatment consisted of three replicates (n = 10/replicate). At the end of the growth experiment, the highest total body weight, crude protein, digestive enzymatic activity, immune response, and amino acids level were observed in treatments supplemented with amino acids compared to T0. After the growth experiment, fish in all treatments were exposed to Staphylococcus aureus (5×105 CFU/ml). For bacterial challenge trial, the T0 treatment was designated as positive (+ve T0) and negative control (-ve T0). Following the S. aureus challenge, fish fed with amino acids showed a better response to reactive oxygen species and lipid peroxidation, as indicated by the increased levels of catalase and superoxide dismutase. Conversely, the concentration of malondialdehyde gradually decreased in all treatments compared to the +ve T0 treatment. It is concluded that supplementation of amino acids improved the growth, protein content, and immunocompetency against S. aureus in striped catfish. The most favorable outcomes in striped catfish were shown by fish supplemented with T7 diet. These essential amino acids hold potential as efficient supplements for use in the intensive aquaculture for striped catfish.

Evaluation of Dietary Essential Amino Acid Supplementation on Growth, Digestive Capacity, Antioxidant, and Intestine Health of the Juvenile Redclaw Crayfish, Cherax quadricarinatus.

The present study was an 8-week feeding trial investigating the effects of lysine and threonine supplementation in vegetable-based diets on growth, antioxidative capacity, and gut microbiota of juvenile redclaw crayfish, Cherax quadricarinatus (initial weight 11.52 ± 0.23 g). The lysine and threonine were supplemented to formulate five isonitrogenous (37%) and isolipidic (9%) diets containing 0% (control), 0.2% lysine (L0.2), 0.2% threonine (T0.2), 0.4% lysine (L0.4), and 0.4% threonine (T0.4), respectively. Compared to the control, weight gain rate (WGR) and specific growth rate (SGR) of C. quadricarinatus significantly increased with increasing dietary lysine and threonine supplementation from 0.2% to 0.4% (P < 0.05). Hepatopancreas trypsin activity significantly increased with increasing levels of lysine and threonine in diets (P < 0.05). However, the pepsin, lipase, and amylase activities were not affected by dietary levels of lysine and threonine (P > 0.05). Compared with the control, crayfish in T0.4 and L0.4 showed significantly higher glutathione peroxidase (GPx) activity (P < 0.05), lower alanine aminotransferase (ALT) activity, and lower malondialdehyde (MDA) content (P < 0.05). Supplementation with 0.4% lysine significantly changed the composition of the gut microbiota (P < 0.05), which showed a significantly increased relative abundance of Proteobacteria and decreased Firmicutes, Actinomycetes, and Pontomyces (P < 0.05). The PICRUSt analysis demonstrated that the abundance of the metabolism and cellular processes pathways in the L0.4 group were markedly decreased compared with the control (P < 0.05). Meanwhile, a tighter interaction of the microbiota community in crayfish was observed in the T0.4 experimental group. In conclusion, these results suggested that dietary supplementation with 0.4% threonine could significantly promote growth and improve microbial health in juvenile C. quadricarinatus.

Effects of Dietary Supplementation of Lysine and Methionine on Growth Performance, Blood Parameters and Body Composition of Common Carp (Cyprinus Carpio) Fingerling

Effects of Dietary Supplementation of Lysine and Methionine on Growth Performance, Blood Parameters and Body Composition of Common Carp (Cyprinus Carpio) Fingerling

Effect of Milk or Milk Derived Food Supplementation on Body Composition of Young Indian Women

Background: Lysine intake in India is low mainly due to consumption of cereals as staple diet and processing loss of lysine. The present study was aimed to assess the impact of supplementation either in the form of dietary supplements of lysine, calcium and vitamin D in order to identify an appropriate approach for the improvement of body composition. Methods: One hundred and twenty volunteer subjects in the age group of 20-30 years residing in Punjab Agricultural University hostels were selected for supplementary trial. Supplementation of milk and its products in amounts to fill the gap of dietary intake and adequacy of protein as well as limiting amino acid lysine in their diets for a period of 12 weeks was done to determine its effect on body composition. Result: The diets were also poor in protein quality as the limiting amino acid lysine was only 55% of the recommended level. Supplementation of milk and its products resulted in a significant reduction in body fat (6.62%) and visceral fat rating (9.47%) and a significant increase in skeletal muscle mass (3.98%) and bone mass (2.72%). The study recommends that improving the quality of diets through dietary supplementation of lysine, calcium and vitamin D is an effective approach to achieve optimum body composition.

Effect of Dietary Lysine and Methionine Supplementation on the Growth and Physiological Responses of Pearlspot Fingerlings, Etroplus suratensis

Background: Successful and sustainable culture of finfish and shellfish depends on the use of nutritionally balanced, low-cost and eco-friendly feeds. This experiment was conducted to evaluate the effect of dietary supplementation of lysine and methionine on the growth and physiological responses of juvenile pearlspot, Etroplus suratensis. Methods: Fingerlings with an average initial body weight of 8.7±0.04 g were distributed to the 300 L FRP tank (n=30 pieces/tank). The pearl spot fingerlings were fed with isonitrogenous (25% Crude protein) feeds supplemented with methionine (1.8, 2.2 and 2.6 g/100 g of diet) and lysine (0.5, 0.9 and 1.3 g/100 g of diet). The growth performance and physiological response of the fishes were assessed. The feeding trial was conducted for a period of 60 days. Result: The methionine supplemented diets at 2.2 g/100 g (T2) and Lysine supplemented diet at 0.9 g/100 g (T5) yielded the best results within the treated groups in terms of average body weight gain, FCR (feed conversion ratio), SGR (specific growth rate), PER (protein efficiency ratio) and FER (feed efficiency ratio). The maximum mean body weight gain recorded in methionine supplemented diet was 20.68±0.20 g in T2 and the maximum mean body weight gain recorded in lysine supplemented diet was 19.6±0.15 g in T5. The mean body weight gain in control was recorded as 12.12±0.20 g. The present study revealed that methionine incorporation at 2.2 g/100 g (T2) and lysine incorporation at 0.9 g/100 g (T5) resulted in better growth performance of the pearl spot Etroplus suratensis fingerlings. Results of challenge tests confirmed that V. anguillarum could act as a primary pathogen for pearlspot reared in freshwater. In the present study, the Hb, RBC, MCV, MCH and MCHC were also affected by dietary methionine and lysine supplementation and were found significantly (p less than 0 .05) higher in fish fed methionine at 2.2% and lysine at 0.9% of diet, indicating that dietary methionine and lysine supplementation activates immune response and promotes fish health. Second-order polynomial regression analysis of weight gain against dietary methionine and lysine levels indicated that the optimum dietary methionine and lysine requirement for maximum growth and feed utilization of pearlspot fingerlings was methionine at 2.2% and lysine at 0.9%.

Dietary lysine supplementation improves growth performance and skeletal muscle development in rabbits fed a low protein diet

The purpose of this study was to investigate the effects on growth of Lysine (Lys) supplementation in a low protein diet. We also investigated the gene or protein expression related to skeletal muscle development and intestinal amino acid transporters, and determined the major signalling associated with Lys-regulating skeletal muscle development. 1000healthy, weights averaging 938.6±6.54g weaned rabbits were randomly divided into five groups (five replicates in each group and 40 rabbits in each replicate). These groups consisted of the normal protein group (NP group, consuming a diet containing 16.27% protein), the low protein group (LP group, 14.15%-14.19% protein) and the LP group with an addition of 0.15%, 0.3% or 0.45% Lys. The trial included 7 d of pre-feeding and 28 d of exposure to the treatment. Compared with NP diet and LP diet, LP+0.3% Lys group improved growth performance (p<0.05), full-bore weight and half-bore weight of rabbits (p<0.05). The LP+0.3% Lys group also resulted in a decrease in the excretion of faecal nitrogen and urinary nitrogen (FN; UN; p<0.05), and an increase in nitrogen utilisation rate (NUR; p<0.05). LP diet increased the mRNA expression of MSTN and WWP1, and decreased the mRNA expression of IGF1 (p<0.05). LP diet decreased the protein expression of P-P70S6K1, P-4EBP1 and P-S6 (p<0.05). LP+0.3% Lys group attenuated the effects of LP diet on the expression of MSTN, WWP1, IGF1, P-P70S6K1, P-4EBP1 and P-S6 (p<0.05). LP+0.3% Lys group resulted in an increase in mRNA expression of MyoD and protein expression of P-mTOR relative to the NP and LP groups (p<0.05). In summary, the addition of Lys to a LP diet provides a theoretical basis for the popularisation and application of Lys in rabbit production.

Utilization of different lysine isomers: A case study on the growth, metabolic enzymes, antioxidant capacity and muscle amino acid composition in Macrobrachium rosenbergii

An 8-week feeding trial was conducted to compare the effects of different lysine isomers on growth performance, amino acid metabolism-related enzyme activities, antioxidant capacity and muscle amino acid composition of giant river prawn (Macrobrachium rosenbergii). The basal diet was formulated to be low in lysine and contained only 10.9 g/kg lysine. The other three experimental diets were supplemented with 12 g/kg D-lysine, L-lysine, and DL-lysine, respectively. Dietary lysine supplementation improved the growth rate and feed utilization of M. rosenbergii, but significant differences were only found between the prawn fed the control diet and the L-lysine diet. L-lysine supplementation significantly improved the intestinal and hepatic trypsin activities, but unaffected the lipase and amylase activities. The highest hepatic aspartate aminotransferase and alanine aminotransferase activities were observed in prawn fed the L-lysine diet, whereas the highest γ-glutamyl transferase activity was found in prawn fed the D-lysine diet. D-lysine supplementation significantly increased the intestinal and hepatic D-amino acid oxidase activities. However, L-lysine supplementation improved the hepatic lysozyme activity and total antioxidant capacity, depressed the hepatic lactate dehydrogenase and alkaline phosphatase activities. Conversely, D-lysine supplementation generally depressed the hepatic superoxide dismutase and peroxidase activities, and nitric oxide content. Furthermore, L-lysine supplementation increased the muscle aspartic acid, serine, glutamic acid, alanine, lysine, arginine, delicious amino (DAA), non-essential amino acids, total amino acids (TAA) contents and DAA/TAA ratio. These results indicate that M. rosenbergii can effectively utilize L-lysine for growth; D-lysine may partly be used but reveal specific toxic effects on antioxidant response.

Lysine supplemented to poultry by‐product meal replacement diet modulates body growth, metabolism and related gene expressions of hybrid sturgeon (Acipenser schrenckii ♀ × Acipenser baerii ♂)

Hybrid sturgeon (Acipenser schrenckii♀×Acipenser baerii♂) were fed with four isonitrogenous (approximately 43.0%) and isolipidic (approximately 13.6%) diets: FM-based diet (lysine control diet, LC diet), poultry by-product meal totally substitute diet (lysine low diet, LL diet), LL diet supplemented lysine to match the LC diet group level (lysine medium diet, LM diet) and LL diet supplemented lysine over the LC diet group level (lysine high diet, LH diet) for 8 weeks to determinate the effect of dietary lysine supplementation on growth performance, metabolism and immunity response. The results indicated that compared with control diet, LL diet led to depressed growth performance and feed utilization. Lysine supplementation had a significant effect on improving the growth performance and feed utilization. Moreover, LL diet also decreased the plasma-free amino acid concentration, nutrient content and mRNA expression level of IGF system and increased plasma immunity indexes and gene expression level of HSP70 than the control diet. LM diet had marked efficiency to eliminate the differential effects caused by lysine insufficiency. However, high-level lysine addition had undesirable effect on regulating the growth performance, feed utilization, plasma-free amino acid concentration, nutrient content, immunity indexes and gene expression level. Present study demonstrated that poultry by-product meal with lysine addition could totally substitute FM without adverse effects on growth performance, plasma AA concentration, nutrient content and immune response in hybrid sturgeon. Our results provide a solid evidence for using lysine to improve the body growth performance and metabolism in hybrid sturgeon.

Effect of herbal lysine supplementation on performance of broiler chicken

To evaluate the effect of herbal lysine supplementation on performance of broiler chicken, a study was conducted on 200, one day-old commercial broiler chicks randomly distributed into 20 subgroups means five dietary treatments with four replicates per treatment and each replicate had ten birds. Feeding trial was conducted for 42 days. The control group (T1) was offered maize-soybean meal based diet without lysine while in second group (T2) basal diet was supplemented with 100% synthetic lysine. In T3 group basal diet was supplemented with 50% herbal + 50% synthetic lysine, while in T4 with 100% herbal lysine and in T5 with Herbal lysine at 50% Higher Level Than T4 group. Feed intake (g/bird), body weight gain (g/bird) significantly (P< 0.05) increased in T4 group as compared to the non supplemented group (T1). Feed conversion ratio was significantly better with herbal lysine supplementation as compared to synthetic lysine and the control. Dietary supplementation of herbal lysine resulted in slightly higher dry matter metabolizability, gross energy metabolizability and nitrogen retention as compared to control group. Thus, it can be concluded that supplementation of herbal lysine at 100% level was found to improve the growth performance in terms of body weight gain, feed conversion ratio, nutrient metabolizability and achieving profitable poultry production.

Abstract P026: The Accumulation Of Lysine In The Kidney Cortex Protects From Proximal Tubule Damage And Salt-Sensitive Hypertension.

The kidneys are highly sensitive to metabolic changes. Metabolic phenotyping uncovered a number of pathways associated with high blood pressure and kidney diseases, which sheds light on the complex pathophysiology of hypertension and associated kidney injury. However, the mechanisms underlying the effects of dietary interventions on kidney function and associated changes in cellular metabolic intermediates remain incompletely understood. L-lysine, one of the essential amino acids, is necessary for many physiological functions. Among all organs, the kidney is a key organ in lysine turnover and metabolism, in particular for modified lysines. Our recent metabolomics study revealed that intrarenal levels of L-Lysine are reduced in Dahl salt-sensitive (SS) rats fed an HS diet. This finding provided further evidence that L-Lysine is critical for metabolic states in the kidney. Using a well-established SS rat model of hypertension and kidney injury, we found that administration of lysine at a concentration of 17mg/ml in drinking water counteracted the lysine deficit in kidneys, restored albumin balance, triggered diuresis, and diminished the development of salt-sensitive hypertension (133±2 vs. 165±4 (136±4 vs. 166±7), mmHg in L-Lysine treated rats vs. control rats male (female) after 14 (21) days of an 8 (4) % NaCl diet). HPLC analysis revealed a significant elevation of lysine in the renal cortex of treated rats. In contrast, the concentration of other amino acids, such as glycine and arginine, did not change with increasing blood pressure. Overall, dietary lysine supplementation of SS rats on the HS diet leads to significant protection of proximal tubule damage, shown by Kim-1 immunostaining. Also, it restores kidney function by the rapid excretion of the pathologically accumulated renal albumin and rebalancing megalin abundance. Moreover, the analyses of glomerular damage showed improvement for the lysine treated group. In conclusion, dietary L-Lysine supplementation significantly enhanced cardiorenal protection via acute inhibition of metabolic load and oxidative stress triggered by hypertension.

EVALUATION OF DIETARY SUPPLEMENTATION OF L-LYSINE AND PHYTASE IN CORN GLUTEN MEAL-SOYBEAN MEAL BASED DIETS FOR PACIFIC WHITE SHRIMP PENAEUS VANNAMEI (BOONE, 1931)

An eight-weeks feeding trial was conducted to study the effects of dietary L-lysine and/or phytase supplementation in corn gluten meal-soybean meal (CGM-SBM) protein blend diets on the growth, apparent digestibility, whole body chemical composition and digestive enzyme activity of Pacific white shrimp Penaeus vannamei (Boone, 1931) juveniles. Five isonitrogenous and isolipidic diets were formulated viz., control diet (T0), with 20% fishmeal was compared against four CGM-SBM based diets, T1 with no supplementation, T2 supplemented with L-lysine, T3 supplemented with phytase and T4 supplemented with L-lysine + phytase. Dietary lysine supplementation had a significant effect (p&lt;0.05) on growth performance and feed conversion ratio (FCR), while supplementation of dietary phytase had no effect on growth performance. Apparent digestibility coefficient (ADC) value for crude protein increased by 2.5 to 3% on supplementation of phytase (500 FTU kg-1 feed) in the diets. The protein digestibility increased by 8 to 11% with the addition of dietary phytase than other treatment groups with no supplementation of phytase. The amylase and lipase enzyme activity of T3 and T4 supplemented with dietary phytase was higher than the groups that were not supplemented with dietary phytase. Higher protease activity was observed in T2 diet supplemented with dietary L-lysine. L-lysine and phytase supplementation in plant based CGM-SBM protein blend diets resulted in better growth performance of P. vannamei.

Effects of dietary L‐lysine supplementation on growth, body composition and muscle‐growth‐related gene expression with an estimation of lysine requirement of GIFT tilapia

An 8-week feeding trial was conducted with extruded practical diets containing 320 g/kg of crude protein from plant-based sources to determine the effects of L-lysine on growth performances, muscle-growth-related gene (myoD, myogenine and myostatin) expression and haemato-biochemical responses in juvenile genetically improved farmed tilapia (GIFT). Five isonitrogenous and isoenergetic diets were formulated to contain graded levels of lysine (14.3, 16, 17.5, 19 and 20.5 g/kg of diet). Each diet was randomly assigned to triplicate groups of 30 juvenile fish (5.2 ± 0.1 g), which were fed thrice a day (9:00, 13:00 and 17:00 hr). Maximum growth performances were observed in fish fed with lysine at 19 g/kg of diet. There was no significant (p > .05) effect on whole-body composition and amino acids profile by dietary lysine supplementation. Significant (p < .05) changes were observed in relative expression of muscle-growth-related genes namely myoD and myogenine and in plasma metabolites by dietary lysine supplementation. In contrast, the relative expression of myostatin was not affected by dietary lysine supplementation. Broken-line regression analysis and second-order polynomial regression analysis of weight gain and N gain against dietary lysine levels showed that the dietary lysine requirement for juvenile GIFT tilapia was 18–18.3 g/kg of diet and 19.3–19.5 g/kg of diet, respectively.

The dietary lysine requirement for optimum protein retention differs with rainbow trout (Oncorhynchus mykiss Walbaum) strain

A 12-week feeding trial was conducted to compare the dietary lysine requirement of a fast-growing strain (FGS) and a slow-growing strain (SGS) of rainbow trout, Oncorhynchus mykiss. Five isonitrogenous (37% digestible protein) and isocaloric (17.6 MJ/kg of digestible energy) diets were formulated and supplemented with l-lysine HCl (98.5% lysine) in increments of 0.40% (1.80, 2.20, 2.60, 3.00 and 3.40% diet) resulting in analyzed lysine values of 1.83 (Lys1.83), 2.20 (Lys2.20), 2.67 (Lys2.67), 3.06 (Lys3.06) and 3.52 (Lys3.52) g/100 g diet, respectively. Juvenile rainbow trout from the FGS (initial weight 12.2 ± 0.3 g) and the SGS (initial weight, 8.54 ± 0.19 g) were randomly stocked to 145-L tanks, each containing 35 fish per tank, in a 2 by 5 factorial design. Each diet was fed to three replicate tanks of each strain to apparent satiation three times daily. After 12 weeks of feeding, the FGS had significantly higher final weight and daily feed intake (g/fish) than the SGS. No significant diet by strain interactions were detected. Dietary lysine significantly improved body weight gain, and calculated indices of weight gain in both strains up to 2.20% dietary lysine, but not higher. However, whole body crude protein and crude lipid levels significantly increased and decreased, respectively, in both strains with increasing dietary lysine supplementation up to 2.7%–2.8% using broken line regression. The only significant difference between strains was found in protein retention, indicating differences in lean body weight gain. Using broken-line regression analysis of protein retention, the optimum dietary lysine level for the FGS and SGS were 2.75 (6.18) and 2.23 (5.01) % of diet (% of dietary protein), respectively. Lysine retention decreased with increasing dietary levels in both strains. Whole body essential amino acid content, with the exception of arginine, showed significant increases with dietary lysine levels in both strains of rainbow trout. Liver aspartate transaminase activity significantly increased with increasing dietary lysine in both strains, but alanine transaminase activity did not. The results suggest that the optimum dietary lysine requirement of rainbow trout for lean-body growth and protein retention differs with fish strain and is independent of feed intake.

Ffects of dietary methionine and lysine supplementation on growth performance, meat composition and rumen fermentation pattern in goats

This experiment was conducted to determine the effect of methionine and lysine supplementation on growth performance, meat quality and rumen fermentation parameters in growing goats. Twenty Xiangdong black goats with initial body weights of 18.1 ± 2.07 kg were used and randomly assigned into four treatments including: no additive (Control), 1.27% Methionine (T1), 2.45% Lysine-HCl (T2), 1.27% Methionine plus 2.45% Lysine-HCl (T3). After 28 days of feeding, the goats were slaughtered and samples were collected for the study. Supplementation of methionine and lysine had no effect on growth performance, meat quality, tissue chemical composition and rumen fermentation parameters. These findings suggest that the mode of supplementation of methionine and lysine used failed to detect the variation.

The Effect of Barley and Lysine Supplementation of Pasture-Based Diet on Growth, Carcass Composition and Physical Quality Attributes of Meat from Farmed Fallow Deer (Dama dama).

Simple SummaryInterest in deer farming has become more popular in European countries and, thus, production of venison under farm conditions is of utmost importance. Despite an increasing demand and interest in venison, only a few studies summarizing the effects of different diets on the growth, carcass parameters and the quality of meat from fallow deer have been published. Our study was the first to evaluate the effects of dietary barley and lysine supplementation on carcass parameters and physical quality of venison from farm-raised fallow deer. Supplementation with barley increased live weight gain, slaughter and carcass weights and fatness characteristics, whereas the addition of lysine to the barley-supplemented diet reduced the amounts of internal and carcass fat.Fallow deer (Dama dama) are important meat producing species providing venison and other products to an international market. The present study investigated the effects of different feed rations on the growth, carcass characteristics and physical attributes of the longissimus lumborum (LL) and semitendinosus (SET) muscles of 45 farm-raised male fallow deer. The animals were divided into three separate groups: 15 pasture-fed (P), 15 pasture-fed and supplemented with barley (B), and 15 pasture-fed and supplemented with barley and lysine (BL). The animals were slaughtered at an average age of 17 months at three time points: after 155, 169 and 183 days on feed. The addition of barley to the feed ration significantly increased weight gain and had positive effects on slaughter and carcass weights, dressing-out proportion, carcass composition, the weight of LL muscle, and increased the redness, yellowness and chroma values of LL muscle. The supplementation with lysine reduced the amounts of carcass and internal fats without compromising other economically important traits.

Effects of dietary methionine and lysine supplementation on nutrients digestion, serum parameters and mRNA expression of related amino acid sensing and transporting genes in growing goats

Sufficient amino acid is necessary to the growth of animals. The experiment investigated the effects of dietary unprotected methionine (Met) and lysine (Lys) sources on nutrient digestion, nitrogen utilization and mRNA expression of related genes in growing goats fed a maize stover-based diet. Twenty Liuyang black weather goats were used and assigned randomly to 4 dietary treatments: (1) the control (basal) diet (NS:), (2) control diet with a supplementation of unprotected DL-Met (SM), (3) control diet with a supplementation of unprotected L-Lys-HCI (SL), (4) control diet with a supplementation of unprotected DL-Met and L-Lys-HCI (SML). The experiment showed that there were no differences of DMI (dry matter intake), fecal output, apparent digestibility, energy balance and N balance (P > 0.05). Adding Lys decreased serum threonine, isoleucine, phenylalanine, total amino acids (P < 0.05) comparing with NS, SM and SML (P < 0.05). SL and SML reduced serum Met and arginine compared with NS and SM (P <0.05). Compared to NS, SM and SL, SML lowered serum leucine (P = 0.057). SM, SL and SML had lessen: total cholesterol (TC) and SLC38A2 mRNA expression in jejunum compared to NS (P < 0.05). SM had the lowest mRNA expression of SLC7A7 in jejunum, SLC7A9 in ileum, SLC7A1 in cecum (P < 0.10). NS had the lowest mRNA expression of EIF4B in the duodenum (P = 0.057). Overall, adding a small amount of free Met and Lys did not affect apparent digestibility but changed serum AAs profile and tended to influence protein synthesis resulted from expression changes of related AAs transporters in the specific intestine tract and mTOR pathway. Our findings provided valuable information for improving animal production through amino acid nutrition regulation.

Dietary lysine deficiency increases the incorporation rate of nitrogen-free compounds in muscle of pacu (Piaractus mesopotamicus)

Isotopic experiments are conducted to evaluate turnover rates in fish tissue, especially as a function of nutrition. In 2007, Cerling et al. proposed an approach they named the reaction progress variable, which among other functions, allows to correct for growth during the period of data collection and to treat the isotopic incorporation system as a linear function, irrespective of the growth rate model. The objective of present study was to apply “the reaction progress variable” approach to describe stable isotope turnover in muscle tissue of pacu fed a lysine-deficient and a lysine-supplemented diet in order to determine the incorporation rates of nitrogen-free compounds, considering the correction for increases in mass during turnover. Since in muscle tissue carbon compounds are proteins, nucleic acids, lipids and carbohydrates and nitrogen compounds include only proteins and nucleic acids, the incorporation rates of nitrogen-free compounds were calculated by the difference between the incorporation rates of carbon and nitrogen compounds. The δ13C and δ15N values were adjusted for the increase in mass of fish to determine incorporation rate constants through linear fit. High turnover rates were observed when the increase in mass was considered. There was no effect of the diets on the incorporation rates of carbon compounds into muscle tissue of juvenile pacu. Fish fed the lysine-deficient diet exhibited a higher metabolic δ15N turnover rate, probably because of the greater degradation of nitrogen compounds; consequently, the incorporation rate of nitrogen-free compounds was 1.23% day−1. A higher incorporation rate of nitrogen compounds was observed in fish fed the lysine-supplemented diet and the incorporation rate of nitrogen-free compounds was therefore lower in this group (0.05% day−1). The incorporation rate of nitrogen-free compounds (e.g., lipids and glycogen) into muscle tissue was higher in juvenile pacu fed the lysine-deficient diet compared to animals receiving the lysine-supplemented diet. We therefore propose to adopt the reaction progress variable approach as a more useful tool for describing isotopic incorporation datasets.

Effects of dietary lysine supplementation on performance, egg quality, and development of reproductive system in egg-laying ducks

ABSTRACTThis study was conducted to examine five lysine (Lys) levels (0.75, 0.80, 0.85, 0.90, and 0.95%) to estimate the optimal level of Lys for Longyan laying ducks from 22 to 38 wk of age. Nine hundred Longyan ducks aged 22 wk were assigned randomly to the 5 dietary treatments, where each treatment comprised 6 replicate pens with 30 ducks per pen. Lys had no effects on egg production, egg mass, feed conversion ratio, shape index, Haugh unit, yolk colour, yolk weight, or albumen weight, but the egg weight was improved significantly (P < 0.05) by dietary Lys supplementation, whereas the eggshell thickness, eggshell weight, and eggshell proportion decreased significantly as the Lys levels increased. Dietary supplementation of Lys did not affect the reproductive organ indices or the plasma levels of estradiol, luteinizing hormone, or follicle-stimulating hormone, whereas the plasma level of progesterone declined significantly (P < 0.01) as elevation the concentrations of Lys in the diets. In conclusion, the results indicate that the optimal Lys level in Longyan laying ducks diets is 0.80% to produce eggs with normal egg weight without adverse effects on the eggshell weight, eggshell proportion, or eggshell thickness.

Interaction effects of dietary lipid and lysine on growth feed utilization and body composition of juvenile grass carp (Ctenopharyngodon idella)

An 8-week feeding trial was designed to investigate the effects of varying dietary lipid and lysine levels on the growth, feed utilization, and blood characteristics of juvenile grass carp (Ctenopharyngodon idella). Six diets were formulated to contain one of three lysine levels (1.5, 1.7, and 2.0%) and one of two lipid levels (2.4 and 5.4%). Each diet was randomly assigned to triplicate tanks of 30 juvenile fish (initial body weight, 3.00 ± 0.02 g). The results showed that the weight gain, specific growth rate, feed efficiency, protein efficiency ratio, nitrogen retention, and lipid retention were significantly affected by dietary lipid and lysine levels (P 0.05). All growth and feed efficiency indices decreased with an increasing dietary lipid level and significantly improved with lysine supplementation (P < 0.05). The dietary lipid levels significantly influenced the moisture and lipid contents of the whole body and muscle: the lipid content of tissue significantly increased with increasing dietary lipid and was inversely correlated with tissue moisture content (P < 0.05). The hepatosomatic index, intraperitoneal fat index (IPF), and serum cholesterol and triacylglycerol contents were significantly higher in fish that were fed the high-lipid diet (P < 0.05). Fish fed the low-lipid diet showed significantly higher amino acid concentrations compared to those fed the high-lipid diet, and the amino acid content improved with lysine supplementation (P < 0.05). Furthermore, dietary lipid, lysine, and their interaction had significant effects on growth performance, IPF, and tissue lipid content (P < 0.05). The results of the present study suggest a positive effect of dietary lysine supplementation on the growth and feed efficiency, serum lipid metabolism improvement, and reduction of IPF in juvenile grass carp.

Effects of dietary lysine and methionine supplementation on Ross 708 male broilers from 21 to 42 d of age (I): growth performance, meat yield, and cost effectiveness

SUMMARY The effects of dietary lysine (Lys) and methionine (Met) supplementation on the growth performance and meat yield of male Ross × Ross 708 broilers were determined. A completely randomized block design with 2 × 4 factorial arrangement of treatments was applied. The diets, including 2 Lys levels [100 and 120% of NRC recommended levels (RL)] and 4 Met levels (80, 100, 120, and 140% of RL), were fed from 21 to 42 d of age. A 100% Lys and 100% Met RL diet corresponded respectively to 1.01% and 0.38% calculated levels in the diet. When the broilers were fed Lys at 100% RL, feed conversion ratio (FCR) was lowest when diets contained Met at 120% RL. However, when broilers were fed Lys at 120% RL, FCR was linearly reduced as the inclusion of dietary Met increased. Similarly, BW on d 41 increased and then plateaued when Lys was maintained at 100% RL and as dietary Met increased. However, BW increased linearly as Met level increased and while Lys was maintained at 120% RL. Relative pectoralis major, wing, and front half (pectoralis major, minor, and wings) to carcass yields were increased as dietary Met increased. However, relative leg to carcass yield was decreased by an increase in Met supplementation. Although the cost of the 80% RL Met in the diets was lowest at either Lys level, the amount necessary to produce 1 kg of live body or carcass weight cost the most. Similarly, the use of supplementary Met lowered the ratio of feed cost:cut-up part yield. In conclusion, the improvement in meat yield in response to Met supplementation was mainly due to improvements in relative front half yield rather than in leg yields. In addition, although feed with higher amino acid levels is more expensive, the realized improvements in growth performance and meat yield in response to supplemental Lys and Met in the diets of male broilers from d 21 to 41 made their use cost effective.