Evaluating lysine requirements of nursery pigs fed low protein diets with different sources of nonessential amino acids

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.

Effects of L-lysine·H2SO4 product on the intestinal morphology and liver pathology using broiler model

Background

Lysine is used widely in livestock production due to the shortage of feed protein resources. L-lysine·H₂SO₄ contains L-lysine sulphate as well as fermentation co-products which contain other amino acids and phosphorus. However, there are few articles about L-lysine·H₂SO₄ product regarding intestinal morphology and liver pathology of broiler chickens. In this article, we focus on the absorption and metabolism of L-lysine·H₂SO₄ revealed in the variation of intestinal morphology and liver pathology to determine the tolerance of chicks for L-lysine·H₂SO₄.

Methods

To evaluate the tolerance of broilers for L-lysine·H₂SO₄, 240 one day old broilers were allocated randomly to one of five dietary treatments which included corn-soybean diets containing 0, 1%, 4%, 7% or 10% L-lysine·H₂SO₄ (L-lysine content = 55%).

Results

Supplementation of 1% L-lysine·H₂SO₄ in the diet had no negative effects. However, 4%, 7% or 10% L-lysine·H₂SO₄ supplementation produced negative responses on broiler performance, carcass characteristics, blood biochemistry, and particularly on intestinal morphology and liver pathology compared with broilers fed the control diet.

Conclusion

Our results show that supplementation with 1% L-lysine·H₂SO₄ had no negative effects on performance, carcass characteristics, blood biochemistry, intestinal morphology and liver pathology in broilers, but supplementation with 4%, 7% or 10% L-lysine·H₂SO₄ produced a negative response, particularly with respect to intestinal morphology and liver pathology.

Meeting Global Feed Protein Demand: Challenge, Opportunity, and Strategy

Feed protein supplements are one of the most expensive and limiting feed ingredients. This review offers a comprehensive analysis of how the expected expansion of animal production, driven by the rising world population and living standards for more animal-sourced foods, is creating a global shortage of feed protein supply. Because ruminants, chickens, and pigs contribute to 96% of the global supply of animal protein and aquaculture is growing fast, means of meeting the feed protein requirements of these species are elaborated. Geographic variation and interdependence among China, Europe, and North America in the demand and supply of feed protein are compared. The potential and current state of exploration into alternative feed proteins, including microalgae, insects, single-cell proteins, and coproducts, are highlighted. Strategic innovations are proposed to upgrade feed protein processing and assessment, improve protein digestion by exogenous enzymes, and genetically select feed-efficient livestock breeds. An overall successful and sustainable solution in meeting global feed protein demands will lead to a substantial net gain of human-edible animal protein with a minimal environmental footprint.

Increased lysine: metabolizable energy ratio improves grower pig performance during a porcine reproductive and respiratory syndrome virus challenge

Porcine reproductive and respiratory syndrome virus (PRRSV) reduces grower pig performance. The amino acid (AA) requirements and lysine:metabolizable energy ratio (Lys:ME) of health-challenged pigs for optimum performance are poorly understood. Two experiments were conducted to evaluate the effect of increasing standardized ileal digestible (SID) Lys:ME (g SID Lys per Mcal ME) on growth performance during a PRRSV challenge. In Exp. 1, a total of 379 barrows (51.3 ± 0.3 kg body weight [BW]) were allotted to one of six diets (1.87 to 3.41 Lys:ME) for a 35-d growth study. In Exp. 2, a total of 389 barrows (29.2 ± 0.23 kg BW) were allotted to one of six diets (2.39 to 3.91 Lys:ME) for a 49-d growth study. These isocaloric diets represented 80% to 130% of National Research Council (NRC) SID Lys requirement. For each experiment, pigs were randomly allotted across two barns of 24 pens each with seven to nine pigs per pen (four pens per diet per health status). On day 0, one barn was inoculated with live PRRSV, one barn sham inoculated (control), and all pigs were started on experimental diets. Pen growth performance and feed intake were recorded weekly and gain-to-feed ratio (G:F) was calculated. Breakpoint analysis was used to determine the Lys:ME that maximized average daily gain (ADG) and G:F over the 35 or 49-d test periods for Exp. 1 and 2, respectively. In Exp. 1, increasing Lys:ME increased ADG (quadratic P = 0.01) and G:F (linear and quadratic P = 0.04) in control pigs over 35 d. In PRRSV-infected pigs, ADG and G:F increased linearly with increasing Lys:ME (P < 0.01). The Lys:ME for optimum ADG and G:F during PRRSV challenge was 2.83 and 3.17, respectively, compared to 2.24 and 2.83, respectively, in control pigs using a one-slope broken-line model. In Exp. 2, pigs in the control barn became naturally infected after 21 days post inoculation. Before infection, ADG and G:F increased with increasing Lys:ME in control and PRRSV-infected pigs (linear and quadratic P < 0.05), and optimum ADG and G:F were achieved at 3.02 and 2.92 Lys:ME, respectively, in PRRSV-infected pigs compared to 2.82 and 3.22 Lys:ME, respectively, in control pigs. Over the 49-d period, increasing Lys:ME improved ADG (P < 0.01, linear and quadratic) and G:F (linear P < 0.01) in naturally infected pigs. The response was similar in experimental infection for ADG (P < 0.01, linear and quadratic) and G:F (linear P = 0.01). The optimum ratio for ADG (2.86 vs. 3.12 Lys:ME) and G:F (3.18 vs. 3.08 Lys:ME) were similar between natural and experimental infection. In summary, increasing Lys:ME by 10% to 20% above NRC requirements improved performance and feed efficiency during an experimental and natural PRRSV challenge.

Effect of standardized ileal digestible lysine on growth and subsequent performance of weanling pigs

A total of 320 weanling pigs (all barrows, initially 5.71 kg BW; Line 1050, PIC Hendersonville, TN) were used to determine whether the Lys level fed during one phase of the nursery influences the response to Lys during subsequent phases. Our hypothesis was that feeding decreasing dietary Lys concentration in early phases, but feeding adequate concentrations in later phases might result in similar pig growth as those fed a more conventional approach with step-wise decreases in dietary Lys as pigs become heavier. Eight dietary regimens were used in a split-plot design. There were three dietary phases, and within phase, a high or low standardized ileal digestible (SID) Lys diet was fed. Pigs were fed either 1.35% or 1.55% SID Lys during phase 1 (days 0 to 7), 1.15% or 1.35% SID Lys in phase 2 (days 7 to 21), and 1.05 or 1.25% SID Lys during phase 3 (days 21 to 35). The low dietary Lys concentrations were achieved by reducing both crystalline Lys and intact protein sources from the high Lys diets. From days 0 to 7, feeding high SID Lys improved (P < 0.01) G:F, but no evidence for differences in ADG or ADFI were observed. Similarly, from days 7 to 21, there were no evidence for differences in ADG or ADFI among pigs fed the two Lys levels, but those fed high SID Lys had improved (P < 0.03) G:F. From days 21 to 35, pigs fed the high Lys diet had increased (P < 0.01) ADG and G:F compared with those fed low SID Lys, but there were no effects on ADFI. For the overall trial (days 0 to 35), there were no dietary interactions among phases, indicating that the Lys level fed in each phase did not influence the response to Lys in subsequent phases. Thus, pigs fed the high Lys level during phase 3, regardless of previous Lys levels in phases 1 and 2, had greater (P < 0.05) overall ADG and G:F compared with other treatment groups. In conclusion, relatively low dietary Lys concentrations can be fed in the early nursery phases (approximately 6 to 12 kg) without any negative impact on overall growth performance provided that adequate Lys levels are fed thereafter (12 to 20 kg).