Effects Of Dietary Lysine Levels Research Articles

Effects of Dietary Lysine Level on Growth Performance and Protein Metabolism in Juvenile Leopard Coral Grouper (Plectropomus leopardus).

An 8-week feeding trial was conducted to evaluate the effects of dietary lysine level on growth performance and protein metabolism of juvenile leopard coral grouper (Plectropomus leopardus) and thereby obtained the optimal dietary lysine requirement of P. leopardus. Six isoproteic and isolipidic experimental diets were formulated to contain 1.10%, 1.69%, 2.30%, 3.08%, 3.56%, and 4.36% lysine of diets, respectively. Each diet was assigned at random to triplicate groups of 25 juveniles (initial mean weight is 10.57 g) per tank in a flow-through mariculture system maintained at 27-30°C. Dietary inclusion of 2.30-3.08% lysine improved the weight gain rate (WGR) and specific growth rate and decreased the feed conversion ratio (FCR) of juveniles (P < 0.05). The intestinal digestive enzyme (trypsin, amylase, and lipase) activities were overall enhanced by dietary inclusion of 3.08-3.56% lysine (P < 0.05). The mammalian target of rapamycin (mTOR) signaling pathway was activated in fish fed diets with 1.69-2.30% lysine by upregulating the relative expression levels of hepatic TOR and S6K1 (p70 ribosomal protein S6 kinase 1) but downregulating the relative expression level of hepatic 4E-BP2 (eIF4E-binding protein 2). Conversely, the amino acid response signaling pathway was inhibited in fish fed diet with 2.30% lysine by downregulating the relative expression levels of hepatic GCN2 (general control nondepressible 2), ATF3 (activating transcription factor 3), ATF4a (activating transcription factor 4a), and ATF4b (activating transcription factor 4b). Additionally, dietary 1.69-3.08% lysine enhanced the plasma total protein level and hepatic lysine α-ketoglutarate reductase activity but depressed the blood urea nitrogen level and hepatic adenosine monophosphate deaminase activity (P < 0.05). Moreover, dietary 3.08% lysine increased the contents of whole-body crude protein and total amino acids, while 1.69%-4.36% lysine depressed the whole-body lipid content (P < 0.05). These results indicated that optimal dietary lysine increased the digestive enzyme activities, promoted protein synthesis but depressed protein degradation, and thereby improved the growth performance of P. leopardus. Based on the second-order polynomial model, the optimal lysine requirement of juvenile P. leopardus for WGR, FCR, and lysine deposition was 2.60%-2.97% of diets (4.91%-5.60% of dietary protein).

Effects of dietary lysine level on the growth performance, protein metabolism, and antioxidant status in Hemibagrus wyckioides juveniles

AbstractAn 11‐week feeding trial was conducted to assess the dietary lysine requirement for juvenile Hemibagrus wyckioides. Six isoproteic and isoenergetic diets (41.66% crude protein, 20.56 kJ/g gross energy) containing 1.1%, 1.5%, 1.9%, 2.3%, 2.7%, and 3.1% lysine were prepared to feed juveniles (average initial body weights of 1.25 g), respectively. The weight gain, specific growth rate (SGR), feed conversion ratio (FCR), and protein efficiency ratio significantly improved with the dietary lysine level up to 2.3%, 1.9%, 2.3%, and 2.3%, and then plateaued afterwards. The highest midgut trypsin and lipase activities as well as plasma antioxidant enzyme activities and nitric oxide content but the lowest plasma malondialdehyde content were recorded in fish fed diet with 2.3% lysine. Fish fed diets with 1.9% or 2.3% lysine exhibited the highest plasma total protein and insulin contents, the lowest plasma ammonia content, and relative expression levels of glutamate dehydrogenase in the liver and adenosine monophosphate deaminase in the liver and muscle. Similarly, fish‐fed diet with 2.7% lysine showed the lowest hepatic alanine aminotransferase activity but the highest hepatic expression level of the mammalian target of rapamycin. Broken‐line regression analysis based on SGR and FCR showed that the dietary lysine requirement for juvenile H. wyckioides was 2.04% to 2.09%, while dietary lysine of 2.3% was optimum for the antioxidant status of H. wyckioides.

Effects of dietary lysine levels on growth performance, nutrient digestibility, serum metabolites, and carcase and meat quality of Yacha pigs

The objective was to evaluate the effect of different standardised ileal digestible lysine (SID-Lys) levels on performance, nutrient digestibility, serum metabolites, and carcase and meat traits of Yacha pigs. A total of 50 pigs were blocked by body weight and randomly assigned to five dietary treatments with six replicate pens (2 pigs/pen) per treatment using a randomised complete block design. Five diets in mash form were formulated to contain SID-Lys at 0.57%, 0.62%, 0.67%, 0.72%, 0.77% of diet in phase 1 (15 ∼ 30 kg), at 0.40%, 0.48%, 0.56%, 0.64%, 0.72% of diet in phase 2 (30 ∼ 50 kg), and at 0.30%, 0.39%, 0.48%, 0.57%, 0.66% of diet in phase 3 (50 ∼ 90 kg), respectively. The results showed that the average daily gain and gain to feed ratio increased with increasing dietary Lys levels in phases 1 and 2 (p ≤ 0.05). Increasing dietary Lys levels increased linearly (p ≤ 0.05) apparent total-tract digestibility of dry matter, gross energy, crude protein, and phosphorus in Phase 3 and also increased (p ≤ 0.05) concentration of serum glucose and tended to increase (p < 0.10) serum total protein in Phase 2. Compared with the Lys deficiently treatment, the adequate Lys treatment had increased carcase weight, lean meat percentage, and shear force and decreased cooking loss (p ≤ 0.05). Moreover, the optimal dietary SID-Lys levels preliminarily determined for 15 ∼ 30 kg, 30 ∼ 50 kg, and 50 ∼ 90 kg Yacha pigs were 0.760%, 0.628%, and 0.553% of the diet, respectively. HIGHLIGHTS Dietary appropriate SID-Lys levels can improve performance and feed utilisation in Yacha pigs. Dietary appropriate SID-Lys levels contributed to enhancing carcase lean meat yield of Yacha pigs.

O71 Effects of dietary lysine levels on feed intake of weanling-growing pigs—a possible role of serum amino acids profile

O71 Effects of dietary lysine levels on feed intake of weanling-growing pigs—a possible role of serum amino acids profile

Effects of Dietary Lysine Levels on Growth Performance, Nutrient Digestibility, Serum Metabolites, and Meat Quality of Baqing Pigs.

Simple SummaryThis study investigated the effects of different standardized ileal digestible (SID) Lys levels on growth performance, nutrient digestibility, serum metabolites, and carcass and meat traits of Baqing pigs. The results revealed that the addition of dietary SID Lys was beneficial for the average daily feed intake (ADFI), gain to feed ratio (G/F), and average daily gain (ADG) of Baqing pigs at the growth phase. The serum concentrations of triglycerides, lysine, and histidine increased by increasing dietary Lys levels. Compared with the treatment three group, dietary SID Lys addition content at treatment four increased the shear force of the longissimus dorsi muscle, but it did not affect the other carcass and meat traits. The SID Lys requirement of 20–40 kg, 40–60 kg, and 60–90 kg of Baqing pigs fed corn–soybean meal-based diets is estimated to be 0.92%, 0.66%, and 0.55% of the diets, respectively.This study was carried out to determine the Lys requirements of Baqing pigs and the effects of different dietary lysine levels on growth performance, apparent nutrient digestibility, serum metabolites, and carcass and meat traits. A total of 120 castrated Baqing pigs were selected by body weight and randomly assigned to five dietary treatments with six replicate pens (4 pigs per pen, castrated) per treatment in a randomized complete block design. Five diets in mash form were formulated to contain SID Lys at 0.56%, 0.68%, 0.80%, 0.92%, and 1.04% of diet in phase 1 (20–40 kg), at 0.45%, 0.54%, 0.63%, 0.72%, and 0.81% of diet in phase 2 (40–60 kg), and at 0.39%, 0.47%, 0.55%, 0.63%, and 0.71% of diet in phase 3 (60–90 kg), respectively. The results showed that the bodyweight of pigs was not affected by dietary SID Lys content during each period. However, the addition of dietary SID Lys linearly reduced F/G in the first period and quadratically increased ADG during the second period (p < 0.05). The digestible energy (DE) was increased linearly and quadratically in the first phases with the dietary increased SID Lys levels, while DE was reduced in the third and second phases (p < 0.05). Increasing SID Lys contents linearly increased the serum TG concentration and quadratically decreased the serum GLU concentration, while linearly reducing the serum HDLC concentration of first period pigs (p < 0.05). Serum concentrations of TP, TG, TC, and LDLC were increased linearly with the increasing dietary SID Lys levels in the second period (p < 0.05). The serum concentrations of Lys increased quadratically, and histidine increased linearly with the increased dietary SID Lys levels (p < 0.05). Compared with the treatment three group, dietary SID Lys addition content at treatment four increased the shear force of the longissimus dorsi muscle (p < 0.05), but it did not affect the other carcass and meat traits. The optimal SID Lys requirement of 20–40 kg, 40–60 kg, and 60–90 kg of Baqing pigs fed corn–soybean meal-based diets is estimated to be 0.92%, 0.66%, and 0.55% of the diets by the quadratic curve models, respectively.

Dietary lysine level affects digestive enzyme, amino acid transport and hepatic intermediary metabolism in turbot (Scophthalmus maximus)

Lysine is one of the most important essential amino acids in fish, especially in the feed formulated with high levels of plant ingredients. Lysine restriction always led to growth inhibition and poor feed utilization. However, little information was available on its effects on digestion, absorption, and metabolism response in fish. In the present study, three experimental diets were formulated with three lysine levels, 1.69% (LL group), 3.32% (ML group), and 4.90% (HL group). A 10-week feeding trial was carried out to explore the effects of dietary lysine levels on the digestive enzymes, amino acid transporters, and hepatic intermediary metabolism in turbot (Scophthalmus maximus). As the results showed, the activities of lipase and trypsin in ML group were higher than in other groups. Lysine restriction inhibited the expression levels of peptides and amino acid transporters such as PpeT1, y+LAT2, b0,+AT, and rBAT but significantly induced the expression of CAT1. Meanwhile, lysine deficiency elevated the content of T-CHO and LDL-C in plasma, while a higher HDL-C/LDL-C ratio was observed in ML group. For hepatic intermediary metabolism, the increase of lysine level induced the mRNA expression of G6Pase1 and FBPase, but no differences were observed in the expression of the key regulators in glycolysis pathway, such as GK and PK. Furthermore, an appropriate increase in the level of lysine promoted the genes involved in lipolysis, including PPARα, ACOX1, CPT1A, and LPL. However, no differences were observed in the expression of PPARγ, FAS, SREBP1, and LXR, which were important genes related to lipid synthesis. These results provide clues on the metabolic responses on dietary lysine in teleost.

Dietary lysine levels modulate the lipid metabolism, mitochondrial biogenesis and immune response of grass carp, Ctenopharyngodon idellus

A 10-week experiment was conducted to evaluate the effects of dietary lysine levels on growth performance, lipid metabolism, anti-oxidant capacity, mitochondrial biogenesis and immune response of grass carp, Ctenopharyngodon idella. Fish (mean initial weight 51.01 ± 0.17 g) were fed seven diets containing graded levels of lysine (1.69 %, 1.79 %, 1.91 %, 2.01 %, 2.11 %, 2.24 % and 2.31 %). Results showed that fish fed the control diet (1.69 %) showed lower weight gain (WG) and higher feed conversion rate FCR than those fed 2.01–2.31 % lysine (P < 0.05). Viscerosomatic index decreased when dietary lysine increasing from 1.69 % to 2.11 % (P < 0.05). Suitable dietary lysine levels enhanced the lipolysis and mitochondrial biogenesis of grass carp. Total antioxidant capacity (T-AOC) in the liver was higher in fish fed 2.24 % dietary lysine than those fed diets containing 1.69 % and 1.79 % lysine (P < 0.05). The malonaldehyde (MDA) contents in liver decreased when dietary lysine increased from 1.69 % to 2.01 % (P < 0.05). Relative mRNA levels of glutathione peroxidase and catalase in liver and intestine were affected by dietary lysine levels (P < 0.05). B-cell lymphoma 2 (Bcl-2) mRNA level in liver was up-regulated and inhibitor kappa B kinase β (IKKβ) mRNA level in the intestine was down-regulated by increasing dietary lysine levels (P < 0.05). Second-order regression based on WG indicated the suitable level of lysine in feed of grass carp was 2.24 % (6.19 % protein).

Effects of dietary lysine levels on growth performance and antioxidative capacity in channel catfish Ictalurus punctatus

A feeding trial was performed to investigate the effects of dietary lysine levels on growth performance and antioxidative capacity of channel catfish Ictalurus punctatus. Five isonitrogenous and isoenergetic diets with 19.3 (the control), 20.5, 22.1, 23.1 and 24.4 g kg−1 of lysine were formulated. Results showed that compared with the control, 23.1 g kg−1 dietary lysine increased the weight gain rate (WGR) and specific growth rate (SGR), and decreased the feed conversion ratio (FCR; p < 0.05). Based on the quadratic regression analysis of SGR and FCR, the optimal dietary lysine level was 22.2 and 21.9 g kg−1, respectively. As dietary lysine levels increasing from 19.3 to 24.4 g kg−1, the catalase activity increased significantly, while the malondialdehyde content decreased (p < 0.05). The mRNA levels of antioxidative genes in liver were markedly upregulated with the increase of lysine levels (p < 0.05). Meanwhile, the mRNA levels of target of rapamycin (TOR), kelch-like ECH-associated protein 1 (Keap1) and nuclear factor erythroid 2-related factor 2 (Nrf2) were increased (p < 0.05). In conclusion, 22.2 and 21.9 g kg−1 dietary lysine could improve the growth performance of channel catfish. Besides, 24.4 g kg−1 dietary lysine enhanced antioxidative capacity via the TOR/Keap1/Nrf2 signalling pathway.

Salinity levels affect the lysine nutrient requirements and nutrient metabolism of juvenile genetically improved farmed tilapia (Oreochromis niloticus).

This 62-d research aimed to evaluate the effects of dietary lysine levels (DLL) and salinity on growth performance and nutrition metabolism of genetically improved farmed tilapia (GIFT) juveniles (Oreochromis niloticus). Six diets with lysine supplementation (1·34, 1·70, 2·03, 2·41, 2·72 and 3·04 % of DM) were formulated under different cultured salinities in a two-factorial design. The results indicated that supplemental lysine improved the specific growth rate (SGR) and weight gain (WG) and decreased the feed conversion ratio (FCR). Meanwhile, the fish had higher SGR and WG and lower FCR at 8 ‰ salinity. Except for moisture, the whole-body protein, lipid and ash content of GIFT were increased by 8 ‰ salinity, which showed that DLL (1·34 %) increased the whole-body fat content and DLL (2·41 %) increased whole-body protein content. Appropriate DLL up-regulated mRNA levels of protein metabolism-related genes such as target of rapamycin, 4EBP-1 and S6 kinase 1. However, 0 ‰ salinity reduced these protein metabolism-related genes mRNA levels, while proper DLL could improve glycolysis and gluconeogenesis mRNA levels but decrease lipogenesis-related genes mRNA levels in liver. 0 ‰ salinity improved GLUT2, glucokinase and G6 Pase mRNA levels; however, sterol regulatory element-binding protein 1 and fatty acid synthase mRNA levels were higher at 8 ‰ salinity. Moreover, 8 ‰ salinity also increased plasma total protein and cholesterol levels and decreased glucose levels. These results indicated that the recommended range of lysine requirement under different salinity was 2·03-2·20 % (0 ‰) and 2·20-2·41 % (8 ‰) and 8 ‰ salinity resulted in higher lysine requirements due to changes in the related nutrient metabolism, which might provide useful information for designing more effective feed formulations for GIFT cultured in different salinity environment.

Effect of dietary lysine level on the growth performance of orange-spotted rabbitfish (Siganus guttatus) fingerlings

The study aimed to determine the optimum dietary lysine level of the orange-spotted rabbitfish Siganus guttatus Bloch, 1787 (average body weight range of 5.2 to 7.6 gxfish-1). The feeding trial was conducted for 8 weeks employing six experimental diets which were isonitrogenous, isocaloric, and isolipidic (35% crude protein (CP), 18.3 MJxkg-1 of gross energy, and 5% lipid). The lysine content ranged from 1.22 g to 2.12 g lysine xkg-1 dry diet (35 to 70 gxkg-1 CP). Results showed that percent weight gain (PWG), and specific growth rate (SGR) peaked at a lysine level of about 55 gxkg-1 CP equivalent to 1.93 gxkg dry diet-1). Feed efficiencies i.e., protein efficiency ratio and food conversion ratio values as well as survival were not affected by the dietary treatments. Lysine requirement level for juvenile rabbitfish was estimated using both broken-line and quadratic regression analyses of PWG and SGR against dietary lysine levels to be between 15.9 and 18.3 gxkg-1 diet (=45.3 and 52.3 gxkg-1 CP).

Effects of Dietary Lysine Levels on Growth Performance and Glycolipid Metabolism via the AKT/FoxO1 Pathway in Juvenile Largemouth Bass, Micropterus salmoides

A 56-day feeding experiment was conducted to determine the dietary lysine requirement of juvenile largemouth bass (Micropterus salmoides) and investigate the effects of dietary lysine on growth, whole-body composition, and hepatic gene expression related to glycolipid metabolism via the AKT/FoxO1 pathway. The juveniles ( 17.34 ± 0.02 g) were fed six graded lysine levels (2.11% (control), 2.56%, 2.92%, 3.33%, 3.68%, and 4.09%, dry diet). The results showed that the 3.33% dietary lysine level significantly increased the final body weight (FBW), weight gain rate (WGR), and specific growth rate (SGR) and improved the feed conversion ratio (FCR) compared with the control group. The whole-body composition was not significantly affected by dietary lysine levels, while lowest hepatic lipid contents were found in the 2.92% and 3.33% dietary lysine groups. Regarding glycolipid metabolism, compared with the control group, 3.33% dietary lysine improved the protein kinase B (AKT) and inhibited the forkhead box O1 (FoxO1), thus upregulated the pyruvate kinase (PK) mRNA levels to enhance glycolysis. Furthermore, sterol-regulatory element binding protein-1c (SREBP1c) and peroxisome proliferator-activated receptor-γ (PPAR-γ) were downregulated by 3.33% dietary lysine, which caused the downregulation of lipid synthesis-related genes acetyl-CoA carboxylase-1 (ACC) and stearyl-CoA desaturase (SCD) mRNA. In addition, 3.33% dietary lysine promoted the expression of the lipolysis-related genes peroxisome proliferator-activated receptor-α (PPAR-α) and carnitine palmitoyl transferase-1 (CPT1). According to the quadratic regression analysis based on the FCR and SGR values, the optimal dietary lysine levels were estimated to be 3.03% and 3.07% of the diet (6.39% and 6.48% of dietary protein), respectively.

Effects of Dietary Lysine Levels on Production Performance and Milk Composition of High-Producing Sows during Lactation.

Simple SummaryModern sows need increased nutrient levels to meet their lactation needs with a high litter size. Compared with multiparous sows, primiparous sows need to meet their lactation, growth, and developmental needs. Therefore, ensuring lactation nutrient intake for primiparous sows is important, and it increases the productivity of the entire breeding population. The objective of this experiment was to evaluate the effect of dietary lysine (Lys) levels for lactating primiparous sows on multiple reproductive cycles including piglet performance and milk composition. Results showed that increasing dietary Lys levels in lactation was beneficial for the survival rate of piglets, litter weight, piglet weight, and average daily gain (ADG) at weaning. The dry matter and protein concentrations in milk were increased by the increase in dietary Lys level. Therefore, when implementing strategies for improving reproductive efficiency, increasing the dietary Lys levels during lactation must be considered, especially for primiparous sows.Modern genotype sows require enhanced nutrition because of their larger body size and higher reproductive performance than 20 years ago. This study aimed to evaluate the effect of dietary Lys on the lactating of primiparous sows and the second lactating period to minimize sow body weight (BW) loss and maximize the survival rate of piglets and litter gain. A total of 160 primiparous Yorkshire sows were randomly allotted to one of four experimental lactation diets. Formulated to contain 0.84%, 0.94%, 1.04%, and 1.14% standardized ileal digestibility (SID) Lys and balanced in Met, Thr, Trp, and Val. No dietary effects were found on sow body weight (BW) and backfat thickness (BF) change and feed intake during lactation. However, the Lys intake (p = 0.04) of lactation increased linearly with increasing dietary Lys levels. In addition, 1.14% Lys for primiparous sow and 0.94% Lys for second parity sow during lactation increased the survival rate (p = 0.04), weight (p = 0.04), and ADG of piglets at d 21 (p = 0.03). The dietary Lys level did not affect colostrum compositions. However, the dry matter (p = 0.04) and protein (p = 0.03) in milk increased linearly with the increase in dietary Lys levels, whereas moisture decreased linearly (p = 0.05). The level of plasma urea nitrogen (PUN) also increased at d 21 of weaning (p = 0.04). These results indicate that high-yielding lactating sows required 1.14% SID Lys during parity 1, and 0.94% SID Lys during parity 2 to maximize the survival rate of piglets and litter gain, respectively. Moreover, the effects of dietary amino acid (AA) on the production performance of weaning pigs could be mediated through milk composition change.

Effects of dietary lysine levels on growth performance, whole body composition and gene expression related to glycometabolism and lipid metabolism in grass carp, Ctenopharyngodon idellus fry

8 weeks rearing trial was designed to estimate the dietary lysine requirement, and evaluate the effects of dietary lysine on glycometabolism and lipid metabolism of grass carp fry. Six practical diets were prepared to feed 720 fish (initial weight 0.36 ± 0.00 g) with graded lysine levels (1.44%, 1.79%, 1.97%, 2.44%, 2.56% and 2.87%, dry diet). The results displayed that the final body weight (FBW), weight gain rate (WGR) and specific growth rate (SGR) were significantly improved by 2.44% dietary lysine, the same as feed intake (FI) and feed conversion ratio (FCR), compared with those of the control group (1.44% dietary lysine). Whole-body lipid contents diminished with raising dietary lysine levels from 1.44% to 2.44% and thereafter the content increased. Regarding glycometabolism, compared to the control diet, the 2.44% dietary lysine level significantly improved glycolysis by increasing glucokinase (GK) and pyruvate kinase (PK) mRNA levels, meanwhile the 2.87% dietary lysine level promoted gluconeogenesis by significantly increasing phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) mRNA levels. Glycogen synthase (GS) mRNA levels were independent of dietary treatment. For the lipolysis pathway, the 2.44% dietary lysine level caused the upregulation of hormone sensitive lipase (HSL), adipose triglyceride lipase (ATGL) and carnitine palmitoyl transferase-1 (CPT1) mRNA levels in the PPAR signaling pathway. Like the fatty acid synthase (FAS), acetyl-CoA carboxylase-1 (ACC1) and stearyl-CoA desaturase (SCD), the relative mRNA expression of peroxisome proliferator-activated receptor-γ (PPAR-γ) related to lipid synthesis in the PPAR signaling pathway, was not remarkably influenced by dietary lysine levels. Furthermore, sterol-regulatory element binding protein-1 (SREBP1) mRNA levels in the intestine were not clearly affected among all the treatments. According to the broken-line regression analysis, based on the SGR and FCR, the optimum requirements of grass carp fry for dietary lysine were 2.39% and 2.13% of diet (6.34% and 5.65% of dietary protein), respectively. Overall, appropriate dietary lysine levels (2.44%) could improve the growth performance, reduce the whole-body lipid, promote glycolysis and lipolysis.

Effects of low protein diets with amino acids supplementation on biochemical and faeces parameters in weaned piglets

Effects of low protein diets with amino acids supplementation on biochemical and faeces parameters in weaned piglets

Effects of dietary lysine levels on jejunal expression of amino acids transporters and hindgut microflora in weaned pigs

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Effect of dietary lysine level on performance, egg quality and serum biochemical indices of laying pigeons

SUMMARY The objective of this study was to evaluate the effect of dietary lysine level on performance, egg quality and serum biochemical indices of laying pigeons, with the aim of discussing the lysine requirements of laying pigeons. A total of 2,400 healthy pigeons (average body weight: 583 ± 77g) with the age of 40 wk were randomly allocated to 6 treatment groups of 5 replicates with 80 female pigeons each (housed 2 per cage). A 16L:8D light cycle was used. The control group fed the basal diet which was primarily composed of corn-soybean meal with a low lysine level of 0.64%. The lysine levels of the other 5 treatment groups were 0.68%, 0.72%, 0.76%, 0.80%, and 0.84% achieved by adding supplemental lysine to the basal diet. The study had lasted for 12 wk after a 1-wk adaptive phase. The results showed that laying rate and average egg weight of the entire experimental period were significantly influenced by dietary lysine level (P

Effects of dietary lysine levels and lighting conditions on intramuscular fat accumulation in growing pigs.

This study was conducted to test our hypothesis that intramuscular fat (IMF) accumulation increases in pigs fed on a low lysine diet during the dark period than those fed on the same diet during the light period. Using barrows aged 6 weeks, we monitored whether serum glucose and insulin levels were affected by light conditions. Two diets with different levels of lysine, 0.78% (LL diet) and 1.37% (control diet) were prepared. Eight pigs were fed on the diet during the light period, while the remaining pigs were fed during the dark period. The pigs were fed either the LL diet or the control diet. Although IMF contents of Longissimus dorsi (LD) muscle were higher in the pigs fed on a LL diet (p < .05), the light conditions had no effect. Low dietary lysine caused reduction in serum glucose levels (p < .05) and serum insulin levels (p = .0613). However, they were also unaffected by the lighting conditions. To gain further insights, we determined the messenger RNA levels of insulin receptor, insulin receptor substrate 1, acetyl CoA carboxylase, and fatty acid synthase in LD and Rhomboideus muscles and in the liver.

Effects of dietary lysine level on the content and fatty acid composition of intramuscular fat in late-stage finishing pigs

This study was conducted to investigate how dietary lysine level affects the intramuscular fat (IMF) content and fatty acid (FA) composition in late-stage finishing pigs. Nine crossbred barrows [94.4 ± 6.7 kg body weight (BW)] were randomly allotted to three treatment groups (n = 3). Three corn- and soybean-meal-based diets were formulated to meet the National Research Council (2012) requirements for various nutrients except for lysine, whose concentrations were 0.43%, 0.71%, and 0.98% (as-fed basis) for Diets 1 (lysine-deficient), 2 (lysine-adequate), and 3 (lysine-excess), respectively. After 5 wk of ad libitum access to diets, pigs were harvested and longissimus dorsi samples were collected. The IMF content and FA composition of the samples were analyzed by gas chromatography. Results showed that the IMF content of the muscle was increased linearly (P &lt; 0.05) with decreasing dietary lysine level from 0.98% to 0.43%. Dietary lysine level altered the composition of FA, especially the unsaturated FA, in the muscle. Particularly, the percentages of C18:1 n-9 and total monounsaturated FA were higher, whereas the percentages of C18:2 n-6 and total polyunsaturated FA were lower, in the muscle of the pigs fed Diet 1. Collectively, dietary lysine deficiency increased the proportion of monounsaturated FA and decreased the proportion of polyunsaturated FA, which may benefit pork palatability.

Effects of dietary lysine levels on the concentrations of selected nutrient metabolites in blood plasma of late‐stage finishing pigs

Lysine is the first-limiting amino acid (AA) in typical swine diets and plays very important roles in promoting growth performance of pigs. This research was conducted to study the effects of dietary lysine on blood plasma concentrations of protein, carbohydrate, and lipid metabolites of pigs. Eighteen crossbred finishing pigs (nine barrows and nine gilts; initial BW 92.3±6.9kg) were individually penned in an environment controlled barn. Pigs were assigned to three dietary treatments according to a randomized complete block design with gender as block and pig as experimental unit (6 pigs/treatment). Three corn and soybean meal-based diets were formulated to contain total lysine at 0.43%, 0.71%, and 0.98% (as-fed basis) for Diets I (lysine deficient), II (lysine adequate), and III (lysine excess) respectively. After 4weeks on trial, jugular vein blood was collected and plasma was separated. The plasma concentrations of total protein, albumin, urea nitrogen (UN), triglyceride, total cholesterol, and glucose were determined using an ACE Clinical Chemistry System (Alfa Wassermann, Inc., West Caldwell, NJ, USA). Data were analysed using the GLM Procedure with PDIFF (adjust=T) option of SAS. No differences (p>0.10) were found between barrows and gilts for any of the metabolites measured. While there were no differences (p>0.10) between pigs fed Diets II and III in plasma concentrations of UN, albumin, and total cholesterol, the concentration of albumin in these pigs was higher (p<.05) than that of pigs fed Diet I, and the concentrations of UN and total cholesterol in these pigs were lower (p<.05) than that of pigs fed Diet I. There were no differences (p>0.10) among the three dietary treatments in plasma concentrations of total protein, triglycerides, and glucose. These findings indicated that the plasma metabolite profile can be affected by changing dietary lysine content only. Thorough understanding how the plasma metabolite profile is alternated by dietary lysine will facilitate nutrient management for more sustainable swine production.

174 Effects of dietary lysine level and amino acid ratios on nursery pig performance

174 Effects of dietary lysine level and amino acid ratios on nursery pig performance