Relative bioavailability of l-lysine sulfate is equivalent to that of l-lysine HCl for nursery piglets

Modulation of broiler plasma metabolic spectrum by the addition of lysine residue to the diet

Flavour is an important factor in evaluating meat quality, and amino acids and fats are important components affecting meat flavour. In this study, we evaluated the relationship between the variation of lysine residue addition and the slaughter performance and meat quality of broilers, which decreased with the addition of lysine residues but improved the meat quality of the broilers. 10% lysine residue addition was the most beneficial for reducing feed cost and improving meat quality. Meanwhile, the plasma metabolites of broilers fed increasing concentrations of lysine residue supplemented feeds were analysed using liquid chromatography-mass spectrometry (LC-MS). Principal component analysis (PCA) and partial least square discriminant analysis (OPLS-DA) were used screen, the differential metabolites induced by lysine residue. In the broilers 29, 37, 63, 87, 80 and 111 differential metabolites were detected (p < 0.05). Amongst them, 3-iodotyrosine, N-methyl-L-glutamic acid, coumaraldehyde, 2-dimethylphenol, N-methylnicotinamide and L-erythrone were the common differential metabolites between group A and groups B, C, D, E, F and G. The addition of lysine residue was positively correlated with alanine aminotransferase (p < 0.05, r = 0.942) and high-density lipoprotein cholesterol (p < 0.05, r = 0.798) and negatively correlated with aspartate aminotransferase (p < 0.05, r = 0.822). According to the classification of differential metabolites and their enriched pathway analysis, differential metabolites mainly caused changes in amino acid and lipid metabolism. Our study shows that a certain proportion of lysine residue in diet affects the specific metabolic pathway of broilers, which may affect amino acid and fat metabolism by regulating alanine aminotransferase, aspartate aminotransferase and high-density lipoprotein cholesterol, ultimately affecting the flavour.

Evaluation of a novel threonine source for nursery pig diets

Four hundred and eighty (PIC 337 X 1050, PIC Genus, Hendersonville, TN) pigs were used to evaluate a novel threonine source (ThrPro, CJ America Bio, Fort Dodge, IA) for nursery pigs from approximately 7 to 20 kg body weight (BW). After weaning, pigs were sorted by sex and fed a common diet for 1 wk. Upon completion of the first week, pigs were sorted into randomized complete blocks, equalized by weight, within 16 replications. Pigs were allocated to one of three dietary treatments: positive control (POS)—standard ileal digestible threonine-to-lysine ratio (SID; Thr:Lys) 0.60, negative control (NEG)—SID Thr:Lys ≤0.46, and alternative Thr source (TEST)—SID Thr:Lys 0.60. The alternative Thr source included fermentative biomass and was assumed to contain 75% Thr and a digestibility coefficient of 100% based on the manufacturer’s specifications. All other nutrients met or exceeded the NRC recommendations. Growth and intake data were analyzed as repeated measures with a compound symmetry covariance structure using the MIXED procedure in SAS 9.4 (SAS Institute Inc., Cary, NC) with pen as the experimental unit. Treatment, phase, the interaction between treatment and phase, and block were included as fixed effects in the model. Differences in total removals were tested using Fisher’s Exact Test of PROC FREQ. Results were considered significant at P ≤ 0.05 and considered a trend at P > 0.05 and P ≤ 0.10. During the first 14 d, pigs fed TEST had decreased gain-to-feed ratio (G:F; 0.77 vs. 0.80, P = 0.022) compared to POS and increased G:F (0.77 vs. 0.73, P < 0.001) compared to NEG. Over days 14–28, pigs fed TEST had similar G:F (0.71 vs. 0.70, P = 0.112) compared to POS and increased G:F (0.71 vs. 0.63, P < 0.001) compared to NEG. Overall (days 0–28), pigs fed TEST had similar average daily gain (ADG; 0.47 vs. 0.47 kg/d, P = 0.982) and G:F (0.76 vs. 0.74, P = 0.395) compared to POS and increased ADG (0.47 vs. 0.43 kg/d, P < 0.001) and G:F (0.76 vs. 0.67, P < 0.001) compared to NEG. The average daily feed intake was not significantly different across treatments for the entirety of the study. In conclusion, the replacement of crystalline L-Thr with a novel Thr source resulted in similar growth performance in nursery pigs from approximately 7 to 20 kg.

Bioavailability of l-lysine sulfate relative to l-lysine HCl for growing-finishing pigs

The objective of this study was to evaluate the relative bioavailability (RBV) of l-Lys sulfate in comparison to l-Lys HCl based on the growth performance response from approximately 26 to 48 kg and from approximately 68 to 114 kg. The effect of Lys source on blood urea nitrogen (BUN), digestibility of dry matter (DM) and sulfur (S), as well as carcass characteristics was determined. A total of 280 growing pigs (25.9 ± 0.25 kg BW) were randomly assigned to one of seven dietary treatments in 56 pens, with five pigs per pen. The diets included a Lys-deficient basal diet (65% of requirement) and the basal diet supplemented with three graded levels of Lys (75%, 85%, and 95% of requirement), as either l-Lys HCl (78.8% Lys purity) or l-Lys sulfate (54.6% Lys purity). The experiment lasted for 112 d, with four dietary phases: Phase 1 lasted for 4 wk (BW: 25.9 to 47.5 kg), Phase 2 lasted for 3 wk (common commercial diet as washout period), Phase 3 lasted for 5 wk (BW: 67.5 to 98.2 kg), and Phase 4 lasted for 3 or 4 wk to reach an average market weight of 114.2 kg. Fresh fecal samples of pigs fed the highest levels of Lys (both Lys sources) were collected on 7 to 10 days after the beginning of Phase 3 for digestibility assay. Blood samples were collected on day 21 and day 81 to determine BUN. Carcass data were collected at a commercial packing plant. Data were analyzed using PROC GLM of SAS (9.4) according to a completely randomized design with pen as the experimental unit. The RBV of l-Lys sulfate was determined using the multiple regression slope-ratio method. Increasing levels of Lys, independent of source, increased (P < 0.05) BW, ADG, and feed efficiency during Phases 1, 3, and 4; market BW increased linearly (P < 0.01) and backfat and BUN decreased linearly (P < 0.01). Lysine source had no impact on growth performance, carcass characteristics, BUN, or digestibility of S and DM. The RBV of l-Lys sulfate compared with l-Lys HCl was also not different based upon ADG or G:F during Phase 1, 3, or 4. These data suggest that the bioavailability of Lys in l-Lys sulfate and l-Lys HCl is at least equivalent for growing–finishing pigs.