Identification of a Putative Sensor Protein Involved in Regulation of Vesicle Production by a Hypervesiculating Bacterium, Shewanella vesiculosa HM13

Bacteria secrete and utilize nanoparticles, called extracellular membrane vesicles (EMVs), for survival in their growing environments. Therefore, the amount and components of EMVs should be tuned in response to the environment. However, how bacteria regulate vesiculation in response to the extracellular environment remains largely unknown. In this study, we identified a putative sensor protein, HM1275, involved in the induction of vesicle production at high lysine concentration in a hypervesiculating Gram-negative bacterium, Shewanella vesiculosa HM13. This protein was predicted to possess typical sensing and signaling domains of sensor proteins, such as methyl-accepting chemotaxis proteins. Comparison of vesicle production between the hm1275-disrupted mutant and the parent strain revealed that HM1275 is involved in lysine-induced hypervesiculation. Moreover, HM1275 has sequence similarity to a biofilm dispersion protein, BdlA, of Pseudomonas aeruginosa PAO1, and hm1275 disruption increased the amount of biofilm. Thus, this study showed that the induction of vesicle production and suppression of biofilm formation in response to lysine concentration are under the control of the same putative sensor protein.

Optimal feed level during the transition period to achieve faster farrowing and high colostrum yield in sows

This study aimed to determine the optimal supply of lactation feed during the transition period to minimize farrowing duration (FD) and maximize colostrum yield (CY) and quality with the overall aim of reducing piglet mortality. A total of 48 sows were stratified for body weight and assigned to six levels of feed supply (1.8, 2.4, 3.1, 3.7, 4.3, and 5.0 kg/d) from day 108 of gestation until 24 h after the onset of farrowing. The number of total born, live-born, and stillborn piglets; birth time and birth weight of each piglet; and frequency of farrowing assistance (FA) was recorded, and blood samples were obtained from newborn piglets at birth. Live-born piglets were further weighed at 12 and 24 h after birth to record weight gain, which in turn was used to estimate intake and yield of colostrum. Colostrum samples were collected at 0, 12, 24, and 36 h after the onset of farrowing. FD was shortest (4.2 h) at intermediate (3.7 kg/d), longest (7.1 to 7.6 h) at low (1.8 and 2.4 kg/d), and intermediate (5.6 to 5.7 h) at high (4.3 and 5.0 kg/d) feed intake (P = 0.004; mean comparison). FA was lowest (0.7% to 0.8%) at intermediate feed intake (3.7 and 4.3 kg/d) and substantially elevated (4.3% to 4.7%) at both lower and higher feed intake (P = 0.01; mean comparison). The cubic contrast revealed 4.1 kg/d as the optimal feed intake to achieve the shortest FD and to minimize FA. Newborn piglets from second-parity sows were less vital than piglets from gilts as evaluated by blood biochemical variables immediately after birth. CY was greatest at 3.1 kg/d (P = 0.04), whereas the cubic contrast revealed 3.0 kg/d as the optimal feed intake to maximize CY. Concentrations of colostral components were affected by the diet, parity, and their interaction except for lactose concentrations. In conclusion, the study demonstrated the importance of proper feed level during the transition period on sow productivity. Moreover, this study estimated 4.1 and 3.0 kg/d as the optimal feed intake during the transition period to improve farrowing characteristic and CY, respectively, and these two feed intake levels supplied daily 38.8 MJ metabolizable energy (ME) and 23.9 g standardized ileal digestible (SID) lysine (3.0 kg/d) or 53.0 MJ ME and 32.7 g SID lysine (4.1 kg/d). The discrepancy of optimal feed intake for optimal farrowing and colostrum performance suggests that it may be advantageous to lower dietary lysine concentration in the diet fed prepartum.

Identification of a Putative Sensor Protein Involved in Regulation of Vesicle Production by a Hypervesiculating Bacterium, Shewanella vesiculosa HM13

Bacteria secrete and utilize nanoparticles, called extracellular membrane vesicles (EMVs), for survival in their growing environments. Therefore, the amount and components of EMVs should be tuned in response to the environment. However, how bacteria regulate vesiculation in response to the extracellular environment remains largely unknown. In this study, we identified a putative sensor protein, HM1275, involved in the induction of vesicle production in a hypervesiculating Gram-negative bacterium, Shewanella vesiculosa HM13. This protein was predicted to possess typical sensing and signaling domains of sensor proteins, such as methyl-accepting chemotaxis proteins. Comparison of vesicle production between the hm1275-disrupted mutant and the parent strain revealed that HM1275 is involved in lysine-induced hypervesiculation. Moreover, HM1275 has sequence similarity to a biofilm dispersion protein, BdlA, of Pseudomonas aeruginosa PAO1, and hm1275 disruption increased the amount of biofilm. Thus, this study showed that the induction of vesicle production and suppression of biofilm formation in response to lysine concentration are under the control of the same putative sensor protein.

PSIII-34 Standardized ileal digestible lysine requirements for 7- to 15-kg weanling pigs with high-lean genetics fed a corn-soybean meal-based diet

Continued genetic improvement necessitates the verification of nutrient requirements for newly developed pig genotypes. Therefore, the objective was to determine the standardized ileal digestible (SID) lysine requirements for 7- to 15-kg high-lean piglets (TN Tempo × TN70) fed a corn-soybean meal-based diet. A total of 144 piglets (6.51 ± 0.56 kg BW) were assigned to 1 of 6 diets in a randomized complete block design based on BW to give 8 replicate pens each with 3 pigs over a 21-d period. Sex was balanced as 4 replicates for each male and female. Diets contained 1.00, 1.16, 1.32, 1.48, 1.64, or 1.80% SID lysine, achieved by adding crystalline L-Lysine·HCl at the expense of cornstarch. Other indispensable AA were provided to meet the requirements. Individual BW and feed disappearance were recorded weekly and blood was sampled on d 1, 14, and 21. Data were analyzed using MIXED procedure of SAS including the SID lysine concentration as the fixed effect and the block as the random effect. Sex effect was not significant, thus was excluded from the model. The SID Lys requirements were estimated for linear and quadratic broken-line using NLIN procedure of SAS. Lysine content did not affect ADG and ADFI during wk 1, but quadratically increased (P < 0.05) G:F. From d 14 to 21, ADG and G:F increased (P < 0.05) quadratically by increasing dietary lysine content. Overall, increasing dietary lysine content quadratically increased (P < 0.05) ADG and G:F; whereas, plasma urea nitrogen quadratically decreased (P < 0.05). In conclusion, the SID lysine requirements for optimal growth performance of 7- to 15-kg piglets fed corn-soybean meal-based diets based on linear and quadratic broken-line models were 1.27 and 1.38% for ADG and 1.36 and 1.46% for G:F, respectively, thus giving an overall average value of 1.37%.

75 Effects of dietary energy and lysine concentration on feed intake and productive performance of lean growing pigs

The aim of this experiment was to determine the response of growing pigs to different standardized ileal digestible lysine (SID Lys) and net energy (NE) levels. A total of 1,248 crossbred boars and gilts (Pietrain x (Landrace x Large White)), with an initial body weight of 19.9±4.0 kg, were individually blocked in 3 categories. Pigs were distributed in 96 pens (13 pigs/pen). The experiment consisted on a 2 x 2 factorial design with 2 SID Lys (1.20 vs. 1.00 %) and 2 NE levels (2,550 vs. 2,350 kcal/kg), fed for 26 days. Data was analyzed with a two-way ANOVA. No significant interaction was observed between SID Lys and NE. Increasing SID Lys improved ADG (0.721 vs 0.679 kg/d, p< 0.001) and FCR (1.56 vs. 1.65 kg/kg, p< 0.001). Increasing NE had no impact on ADG (0.706 vs. 0.695 kg/d, p=0.100) but improved FCR (1.58 vs. 1.63 kg/kg, p< 0.001) as a result of reduction in ADFI (1.10 vs. 1.15 kg/d, p< 0.001). Therefore, energy intake increased when increasing the energy content of the diet (2799 vs. 2697 kcal NE/d, p< 0.001) and SID Lys intake was reduced (12.2 vs. 12.8 g/d, p< 0.001). In addition, FCR expressed as energy per kg gain was reduced when increasing SID Lys (3.81 vs. 4.04 Mcal NE/kg gain, p< 0.001) whereas increased when increasing NE density (4.02 vs. 3.82 Mcal NE/kg gain, p< 0.001). Differential analysis for small, medium and large pigs showed an interaction between SID Lys and NE in ADG of small pigs during the first 14 days (p=0.028). Pigs fed high lysine and low energy diet had a greater ADG than the ones in the high SID Lys and NE treatment (0.636 vs 0.595 kg/d, p=0.028). In conclusion, growing pigs showed 1) greater ADG when increasing SID Lys above 1.00% 2) no impact of energy level on growth.

High-throughput quantification of carboxymethyl lysine in serum and plasma using high-resolution accurate mass Orbitrap mass spectrometry

Background Carboxymethyl lysine is an advanced glycation end product of interest as a potential biomarker of cardiovascular and other diseases. Available methods involve ELISA, with potential interference, or isotope dilution mass spectrometry (IDMS), with low-throughput sample preparation. Methods A high-throughput sample preparation method based on 96-well plates was developed. Protein-bound carboxymethyl lysine and lysine were quantified by IDMS using reversed phase chromatography coupled to a high-resolution accurate mass Orbitrap Exactive mass spectrometer. The carboxymethyl lysine concentration (normalized to lysine concentration) was measured in 1714 plasma samples from the British Regional Heart Study (BRHS). Results For carboxymethyl lysine, the lower limit of quantification (LLOQ) was estimated at 0.16 μM and the assay was linear between 0.25 and 10 μM. For lysine, the LLOQ was estimated at 3.79 mM, and the assay was linear between 2.5 and 100 mM. The intra-assay coefficient of variation was 17.2% for carboxymethyl lysine, 9.3% for lysine and 10.5% for normalized carboxymethyl lysine. The inter-assay coefficient of variation was 18.1% for carboxymethyl lysine, 14.8 for lysine and 16.2% for normalized carboxymethyl lysine. The median and inter-quartile range of all study samples in each batch were monitored. A mean carboxymethyl lysine concentration of 2.7 μM (IQR 2.0–3.2 μM, range 0.2–17.4 μM) and a mean normalized carboxymethyl lysine concentration of 69 μM/M lysine (IQR 54–76 μM/M, range 19–453 μM/M) were measured in the BRHS. Conclusion This high-throughput sample preparation method makes it possible to analyse large cohorts required to determine the potential of carboxymethyl lysine as a biomarker.

Long-term effects of lysine concentration on growth performance, intestinal microbiome, and metabolic profiles in a pig model

Lysine is a common limiting amino acid in human and animal diets and plays an important role in cell proliferation and metabolism.

Effect of feeding different levels of lysine and protein on the performance of WLH layers

A trial was conducted to evaluate the requirement of digestible lysine at various protein levels in the diet of WLH layers (BV-300) from 25-44 weeks of age. Layers (528) were fed with diets containing two protein levels i.e. 13.36 and 15.78 % each with 5 % concentration variations of lysine (0.50, 0.55, 0.60, 0.65, and 0.70) and a control with 17 % CP and 0.70 % lysine. Each diet was fed to six replicates of eight birds. Egg production, feed intake, body weight were not influenced either by the concentration of lysine or by level of protein in diet. Increased (P d” 0.05) egg weight and egg mass were observed with increasing lysine in diets. Better feed efficiency was observed with increasing lysine concentration. It can be concluded that WLH layers require approximately 0.65% lysine with 13.36% CP or 0.63% lysine with 15.78% CP (i.e. 598.80 vs 570 mg/h/day) in diet.