Lysine Ratio Research Articles

Ideal ratios of standardized ileal digestible methionine, threonine, and tryptophan relative to lysine for male broilers at the age of 1 to 10 days

The objective of this study was to develop ideal amino acid (AA) ratios based on the standardized ileal digestible (SID) lysine, methionine (in the presence of 4.3 g SID cysteine/kg), threonine, and tryptophan requirements, for 10-day-old male broiler chickens. Three experiments were conducted using Ross 308 male chicks fed diets based on corn, soybean meal, and additional graded crystalline AA with 228 g/kg of crude protein. Each diet contained the same amount of basal diets including corn, soybean meal, corn starch, and soybean oil, and graded AA were substituted at the expense of L-glutamic acid in order to keep all diets isonitrogenous. A total of 720 birds were allocated to 6 treatment groups, with 15 birds per cage and 8 cages per treatment using a randomized complete block design. Body weight and group feed intake were measured on day 10. The dietary SID AA levels in each experiment ranged from 2.9 to 6.9 g of methionine/kg, with increments of 0.8 g/kg (Exp. 1), 4.5–8.5 g of threonine/kg, with increments of 0.8 g/kg (Exp. 2), and 1.1–2.1 g of tryptophan/kg, with increments of 0.2 g/kg (Exp. 3), respectively. The methionine requirement was conducted in the presence of 4.5 g total cysteine/kg diet which was 4.3 g/kg diet in SID cysteine. Average daily gain and gain to feed ratio showed linear and quadratic relations to increasing levels of SID methionine, threonine, and tryptophan, respectively (P < 0.01). The SID requirements for broiler chicks at the age of 1–10 days were determined using 12.4 g/kg of SID lysine concentrations in the dietary treatments. The requirement for average daily gain and gain to feed ratios were 3.85 and 3.84 g/kg for SID methionine when the diet contained 4.3 g SID cysteine/kg diet (thus, total sulfur AA requirements were 8.15 and 8.14 g/kg, respectively), 7.11 and 7.38 g/kg for SID threonine, and 1.58 and 1.36 g/kg for SID tryptophan, respectively. By using the upper limit of the broken-line requirement, the ideal SID AA to lysine ratios of 10-day-old broiler chickens were 0.31, 0.60, and 0.13 for methionine (in the presence of 4.3 SID cysteine/kg diet), threonine, and tryptophan, respectively.

Digestible tryptophan requirement for tambaqui (Colossoma macropomum) fingerlings

The objective of this study was to determine the digestible tryptophan requirement of tambaqui (Colossoma macropomum) fingerlings and its relationship with digestible lysine. A total of 300 tambaqui fingerlings with three initial weights (2.12 ± 1.19, 8.13 ± 0.75, and 15.18 ± 1.91 g) were distributed in a randomized complete block design, consisting of six treatments (0.225, 0.256, 0.288, 0.319, 0.350, and 0.381% of digestible tryptophan) and five replicates of 10 fish per plot. The tryptophan to lysine ratio was estimated using a 1.78% level of digestible lysine. Variables regarding performance, food efficiency, and body deposition of protein, fat, and ashes, and nitrogen retention efficiency were evaluated. Feed intake and nitrogen retention efficiency did not vary. For the digestible tryptophan intake, feed conversion and body deposition of ashes, the model that best fit was the Linear Response Plateau, with these variables improving with the elevation of digestible tryptophan concentration up to the levels of 0.335, 0.276 and 0.259%, respectively. Weight gain, specific growth rate, digestible tryptophan efficiency for weight gain, and body deposition of protein and fat increased in a quadratic manner with elevated digestible tryptophan levels; the estimated optimal levels were 0.320, 0.310, 0.280, 0.323 and 0.299%, respectively. The recommended digestible tryptophan level in rations for tambaqui fingerlings is 0.323%, corresponding to 0.108%/Mcal of digestible energy with a digestible tryptophan to lysine ratio of 18%.

Digestible Threonine to Lysine Ratios for Meat-Type Quails

ABSTRACT Three experiments were conducted to estimate the optimal digestible threonine to lysine ratios (Thr:Lys) of meat-type quails during the pre-starter (1 to 7 days), starter (8 to 14 days) and grower I (15 to 21 days) phases. In each experiment, 600 birds were distributed according to a completely randomized experimental design into five treatments, consisting of five dietary Thr:Lys ratios (0.66, 0.71, 0.76, 0.81 and 0.86%), with eight replicates of 15 quails each. Performance parameters and intestinal morphology were evaluated. During the pre-starter phase, feed intake, threonine intake, weight gain, and ileal villus height linearly increased (p<0.01) as dietary digestible Thr:Lys increased. During the starter phase, increasing digestible Thr:Lys ratios had a linear effect (p<0.01) on threonine intake and livability, and linear and quadratic effects (p<0.01) on feed intake. During the grower I phase, increasing digestible Thr:Lys ratios promoted linear increase in threonine intake and feed conversion ratio (p<0.05), and a linear decrease in weight gain. The estimated digestible Thr:Lys ratios recommended for meat-type quails are 0.85, 0.73 and 0.66%, for the pre-starter, starter and grower I phases, respectively.

The effect of different dietary ratios of arginine, methionine, and lysine on the performance, carcass traits, and immune status of turkeys

The research hypothesis postulated that the optimal dietary inclusion levels and ratios of lysine (Lys), arginine (Arg), and methionine (Met) can increase the growth potential of hybrid turkeys and limit metabolic disorders that weaken immune function. The experiment was carried out in a full rearing cycle, from 1 to 16 wk of age, in a two-factorial randomized design with 3 levels of Arg and 2 levels of Met (90, 100 and 110% of Arg, and 30 or 45% of Met, relative to the content of dietary Lys), with 6 groups of 8 replicates per group and 18 turkeys per replicate. In the first and second month of rearing, a significant dietary Arg-by-Met interaction was noted for daily feed intake and body weight gain, and a more beneficial effect was exerted by higher Met content and medium Arg content. Throughout the experiment, the higher dietary Met level increased the final body weight (BW) of turkeys (P = 0.001). Different dietary Arg levels had no influence on the growth performance of turkeys, but the lowest level decreased dressing yield (P = 0.001), and the highest level increased the percentage of breast muscles in the final BW of turkeys (P = 0.003). The lowest Arg level (90% of Lys content) undesirably increased the concentration of the proinflammatory cytokine IL-6 (P = 0.028) and decreased globulin concentration (P = 0.001) in the blood plasma of turkeys. The higher dietary Met level (45% of Lys content) increased plasma albumin concentration (P = 0.016). It can be concluded that higher dietary levels of Met (45 vs. 30% of Lys content) and Arg (100 and 110 vs. 90% of Lys content) have a more beneficial effect on the growth performance and immune status of turkeys.

Nutritional Characteristics of Selected Insects in Uganda for Use as Alternative Protein Sources in Food and Feed.

Insects are potential ingredients for animal feed and human food. Their suitability may be influenced by species and nutritional value. This study was aimed at determining the nutritional profile of four insects: Dipterans; black soldier fly (Hermetia illucens Linnaeus) family stratiomyidae and blue calliphora flies (Calliphora vomitoria Linnaeus) family Calliphoridae; and orthopterans; crickets (Acheta domesticus Linnaeus) family Gryllidae and grasshoppers (Ruspolia nitidula Linnaeus) family Tettigoniidae to establish their potential as alternative protein sources for animals (fish and poultry) and humans. Gross energy, crude protein, crude fat, crude fiber, carbohydrates, and total ash were in the ranges of 2028.11–2551.61 kJ/100 g, 44.31–64.90, 0.61–46.29, 5.075–16.61, 3.43–12.27, and 3.23–8.74 g/100 g, respectively. Hermetia illucens had the highest energy and ash content; C. vomitoria were highest in protein and fiber content, R. nitidula were highest in fat, whereas A. domesticus had the highest carbohydrate content. All insects had essential amino acids required for poultry, fish, and human nutrition. The arginine to lysine ratios of H. illucens, C. vomitoria, A. domesticus, and R. nitidula were 1.45, 1.06, 1.06, and 1.45, respectively. The fatty acids comprised of polyunsaturated fatty acids (PUFAs) and saturated fatty acids (SFAs). Palmitic acid (23.6–38.8 g/100 g of total fat) was the most abundant SFA, exception R. nitidula with 14 g/100 g stearic acid. Linoleic acid (190–1,723 mg/100 g) and linolenic acid (650–1,903 mg/100 g) were the most abundant PUFAs. Only C. vomitoria had docosahexaenoic acid. The study indicates that the insects studied are rich in crude protein and other nutrients and can potentially be used for human and animal (fish and poultry) feeding.

The Limiting Sequence and Appropriate Amino Acid Ratio of Lysine, Methionine, and Threonine for Seven- to Nine-Month-Old Holstein Heifers Fed Corn-Soybean M-Based Diet.

Simple SummaryResearch on the amino acid nutrition of cattle is limited, particularly research on the amino acid patterns of growing heifer. This lack of research has made it difficult to minimize the costs and reduce nitrogen emission of dairy heifers. Lysine might be the first limiting amino acid for seven- to nine-month-old Holstein heifers that are fed a corn–soybean meal-based diet, followed by methionine and threonine. The appropriate ratio of lysine, methionine, and threonine—calculated based on the nitrogen retention of seven- to nine-month-old Holstein heifers—were 100:32:57. We expect to reduce the input of protein feed and nitrogen emissions for dairy farms by using this ratio.An “Amino acid (AA) partial deletion method” was used in this experiment to study the limiting sequences and appropriate ratio of lysine (Lys), methionine (Met), and threonine (Thr) in the diets of 7- to 9-month-old Holstein heifers. The experiment was conducted for three months with 72 Holstein heifers (age = 22 ± 0.5 weeks old; BW = 200 ± 9.0 kg; mean ± standard deviation). Following an initial two weeks adaptation period, heifers were allocated to one of four treatments: a theoretically balanced amino acid diet (positive control [PC]; 1.00% Lys, 0.33% Met, and 0.72% Thr), a 30% Lys deleted diet (partially deleted Lys [PD–Lys]; 0.66% Lys, 0.33% Met, and 0.72% Thr), a 30% Met deleted diet (partially deleted Met, [PD–Met]; 1.00% Lys, 0.22% Met, and 0.72% Thr), and a 30% Thr deleted diet (partially deleted Thr [PD–Thr]; 1.00% Lys, 0.33% Met, and 0.45% Thr). Experimental animals were fed a corn–soybean meal-based concentrate and alfalfa hay. In addition, the animals were provided with supplemental Lys, Met, and Thr (ruminal bypass). The results found no differences in the growth performance and nitrogen retention between PD–Thr treatment and PC treatment (p > 0.05). The average daily gain (p = 0.0013) and feed conversion efficiency (p = 0.0057) of eight- to ninr-month-old heifers were lower in both PD–Lys and PD–Met treatment than those in PC treatment. According to growth performance, Lys was the first limiting AA, followed by Met and Thr. Moreover, nine-month-old Holstein heifers in PD–Lys treatment and PD–Met treatment had higher levels of serum urea nitrogen (p = 0.0021), urea nitrogen (p = 0.0011) and total excreted N (p = 0.0324) than those in PC treatment, which showed that nitrogen retention significantly decreased (p = 0.0048) as dietary Lys and Met levels decreased. The limiting sequence based on nitrogen retention was the same as that based on growth performance. The appropriate ratio of Lys, Met, and Thr in the diet based on nitrogen retention was 100:32:57. In summary, the limiting sequence and appropriate amino acid ratio of Lys, Met, and Thr for seven- to nine-month-old Holstein heifers fed a corn–soybean meal-based diet were Lys > Met > Thr and 100:32:57, respectively.

Different dietary methionine to lysine ratios in the lactation diet: effects on the performance of sows and their offspring and methionine metabolism in lactating sows

BackgroundOver the last decade, the nutritional requirements of lactating modern genotype sows have increased. The current nutritional recommendations might be unable to meet the needs of increased litter size and milk production, and thus the nutritional requirements need to be re-evaluated. The current study was conducted to investigate the effects of dietary methionine to lysine (Met:Lys) ratios on the performance of and methionine metabolism in lactating sows.ResultsDuring the 1st week of lactation, piglets reared on sows in the 0.37 to 0.57 Met:Lys ratio groups grew faster than those reared on sows in the control group (0.27) (P < 0.01). The 0.37-ratio group showed increased levels of GSH-Px in plasma during lactation (P < 0.01) and decreased concentrations of urea nitrogen in the plasma of sows (P < 0.05). Compared with the 0.27-ratio group, the levels of T-AOC and GSH-Px in the plasma and homocysteine in the milk of lactating sows were significantly increased in sows in the 0.47-ratio group (P < 0.01). In sows fed a 0.57-ratio diet, the levels of glutathione and taurine in the plasma and milk were improved significantly during lactation. However, the content of TBARS in the blood (P < 0.05 at day 7 and P = 0.06 at weaning day) was increased (P < 0.01). Moreover, there were linear increases in the levels of homocysteine in the blood and milk of sows during the lactation period (P < 0.01) with increased dietary Met:Lys ratios in the lactation diet.ConclusionsThe current study indicated that increasing the dietary Met:Lys ratio (0.37~0.57) in the lactation diet had no significant effect on the overall performance of sows or the colostrum and milk composition, but it increased piglet mean BW and piglet ADG during the first week of lactation. Increasing dietary methionine levels had no significant effect on antioxidant function in lactation sows, even though it increased levels of GSH and GSH-Px in the plasma of sows during lactation. However, the content of homocysteine in the plasma and milk increased during lactation due to a high level of dietary methionine.

PSV-18 Effects of varying ratio of L-Arginine and Lysine on the performance of sows and their litters

Abstract The objective of the present study was to evaluate the effects of different ratios of L-Arginine and lysine on the performance of sows and their piglets. A total of 12 (Landrace×Yorkshire) sows, with an average parity of 2.3 (from 1 to 4), were subjected to 3 treatments with 4 sows per treatment. Treatments were as follows: 1) CON, Basal diet (L-arginine: Lysine= 0.95), 2) TRT1, CON + Arginine (A: L = 1), and 3) TRT2, CON + Arginine (A: L = 1.05). The supplementation of 1.05 A: L showed reduction in body weight loss after farrowing (linear, P = 0.0105), at weaning (linear, P = 0.0492), and increased the back-fat thickness loss after farrowing (0.00498) and at weaning (0.0204). Dietary supplementation of 1.05 A: L increased (linear, P = 0.0226) body weight of piglets at weaning. In addition, dietary supplementation of L-Arginine tended to increase (linear, P = 0.0103) the average daily gain (ADG) of piglets at weaning. In conclusion, dietary supplementation with L-arginine (A: L = 1.05) exerted positive effects on some of the reproductive performance parameters in sows and growth performance in suckling piglets. These findings may provide an insight into a new nutritional strategy for sows.

PSVI-3 Estimation of the optimal standardized ileal digestible valine to lysine ratio required for growing-finishing pigs in low crude protein diets

Abstract Aim was to determine standardized ileal digestible Val to Lys ratios for growing - finishing pigs fed low CP diets on performance, BUN and carcass characteristics. SID Val to Lys ratios for BW 42.5 to 70.3 kg, 70.3 to 98.1 kg and 98.1 to 128.7 kg pigs. Pigs (n = 400, 10 pens / treatment, 8 pigs / pen) blocked by BW and randomly assigned to 1 of 5 treatments. Diets were SID Val to Lys of 0.55, 0.60, 0.65, 0.70 and 0.75. Data analyzed as a RCBD with PROC MIXED procedure of SAS with pen (experimental unit), treatment (fixed effect), and BW block (random effect). In phase 1, linear and quadratic increase of ADG (Linear, P = 0.03; Quadratic, P = 0.04), BUN decreased (Linear, P = 0.01; Quadratic, P = 0.04). SID Val:Lys for ADG, linear broken-line and quadratic model were 0.64 and 0.66, respectively. BUN for SID Val:Lys were 0.63 (P = 0.01) and 0.70 (P = 0.04). In phase 2, ADG increased (Linear, P = 0.04; Quadratic, P = 0.01) and G:F increased (Linear, P = 0.02; Quadratic, P = 0.04). a linear (P = 0.04) and quadratic (P = 0.01) increase in ADG. SID Val:Lys ADG were 0.66 and 0.70. with the increase of SID Val:Lys ratios. SID Val:Lys for G:F were 0.70 and 0.75, respectively. In phase 3, the SID Val:Lys to maximize ADG were 0.67 (Linear, P = 0.04) and 0.72 (Quadratic, P &lt; 0.01). as the SID Val:Lys increased. Supplementation of low CP diets with high levels of SID Val:Lys increase decreased (Linear, P = 0.02) fat depth, at 0.65. but no effect on other carcass characteristics. In conclusion, SID Val:Lys requirement for ADG in three phases were 0.64, 0.66, 0.67, and 0.66, 0.70, 0.72, using a linear broken-line and quadratic model respectively. BUN and fat thickness appears to be minimized at Val:Lys ratio of 0.65 and a potential to increase lean percentage.

PSVII-4 Optimal standardized ileal digestible lysine and methionine + cysteine to lysine ratio for 12 to 23 kg pigs fed antibiotic-free diets

Abstract Requirement of Lys is affected by lean gain capacity of the pigs. Methionine is the 3rd limiting AA in typical swine diets. In Exp. 1, 108 crossbred pigs (initial BW 11.8 kg) were assigned to 6 diets adequate in all AA but with increasing Lys content [0.90, 1.00, 1.10, 1.20, 1.30 and 1.40% standardized ileal digestible (SID) Lys] to determine the SID Lys requirement. In Exp. 2, 108 pigs (initial BW 11.9 kg) were assigned to 6 diets to determine the optimal SID Met+Cys:Lys ratio. Diets 1 to 5 were varied in SID Met+Cys:Lys (50, 55, 60, 65 and 70%) and 1.17% SID Lys (second limiting). Diet 6 was formulated to be adequate in all AA (1.25% SID Lys and 62% SID Met+Cys:Lys). There were 6 pens (2 barrows and 1 gilt) per treatment in both experiments and lasted for 21 d. Data were analyzed by ANOVA using the GLM procedure of SAS. In Exp. 1, increasing SID Lys increased the overall ADG and G:F (linear, P &lt; 0.001) and decreased plasma urea nitrogen (PUN; linear, P &lt; 0.001). Regression analysis estimated the SID Lys to be 1.36, 1.38 and 1.28% for ADG, G:F and PUN, respectively with an average SID Lys requirement of 1.34% for 12-23 kg pigs. In Exp. 2, increasing SID M+C:Lys ratio (diets 1 to 5) increased ADG and G:F (linear and quadratic, P &lt; 0.001) and decreased PUN (quadratic, P &lt; 0.001). Pigs fed a high Lys diet (diet 6) tended to have a lower PUN (P = 0.076) but performance was not affected. The regression models estimated the optimum SID M+C:Lys ratio to be 63.1 and 60.7% for ADG, and 62.5 and 61.1% for G:F, respectively while 62.9% SID M+C:Lys optimized PUN. On average, the optimal SID M+C:Lys ratio for 12-23 kg pigs was 62%.

Evidence of nutrient by genotype interaction in meat quail strains through reaction norm models

Quails raised under different nutrition levels could lead to genetic variation affecting the genetic gain due to the genotype by environment (GxE) interaction. Thus, reaction norm models were carried out to evaluate the GxE interaction of two meat quails’ strains (LF1 and LF2) raised under different tryptophan:lysine ratios for body weight and carcass traits. A total of 590 and 587 meat quails for LF1 and LF2, respectively, were raised under five different tryptophan:lysine ratios (0.15, 0.20, 0.25, 0.30 and 0.35) in final growth phase diet. The tryptophan:lysine ratios exhibited an important influence on the genetic parameters of body weight and carcass traits. Heritability and additive genetic variance estimates increased as tryptophan: lysine ratios increased, except for body weight at 28 and 35 days in LF2 strain. Lower correlation estimates and re-ranking of estimated breeding values were observed for slaughter weight, breast weight and thigh + leg yield in LF2 strain and for carcass yield in LF1 strain. It indicated a striking effect of amino acid ratios in quail carcass traits. The genetic evaluation and selection for carcass trait in quail strains raised under different tryptophan:lysine ratios should be considered in quail breeding programs.

In vitro methionine supplementation during lipopolysaccharide stimulation modulates immunometabolic gene network expression in isolated polymorphonuclear cells from lactating Holstein cows

Methionine (Met) is one of the 2 most limiting amino acids for milk production in dairy cow diets. The accepted "ideal" ratio of lysine (Lys) to Met (L:M) when formulating diets is 3:1. However, blood from cows fed corn silage-based diets without supplemental rumen-protected Met averages approximately 3.6:1 L:M. Recent in vivo research on cattle immunonutrition has revealed that the immune system could benefit from greater Met supply. To study more closely the effects of different L:M ratios, blood polymorphonuclear cells (PMN) were isolated from 5 Holstein cows in mid-lactation (238 ± 20 d postpartum, 33.8 ± 3.8 kg of milk/d; mean ± SD). The PMN were incubated at 3 different levels of L:M (3.6:1, 2.9:1, or 2.4:1) and stimulated with lipopolysaccharide (LPS) at either 0 or 50 μg/mL for 2 h at 37°C. Target genes were associated with cytokines, pathogen recognition, nuclear receptors, killing mechanisms, and Met and glutathione metabolism. Data were subjected to ANOVA using PROC MIXED in SAS, with L:M, LPS, and their interaction as fixed effects. Stimulation with LPS upregulated genes related to cytokines (IL1B, TNF, IL10 and IL6) and nuclear receptors, including nuclear factor kappa B (NFKB1) and glucocorticoid receptor (NR3C1), and downregulated the mRNA abundance of chemokine receptor 1 (CXCR1), lysozyme (LYZ) and glutathione reductase (GSR). A linear decrease was observed in the mRNA abundance of TNF when L:M was decreased. A similar response was observed for interleukin-1 receptor-associated kinase 1 (IRAK1) and NFKB1 abundance in cells stimulated with LPS (linear effect). A linear increase of LYZ mRNA expression as L:M decreased was detected in unstimulated cells. Furthermore, a decrease in L:M led to a linear decrease of superoxide dismutase 1 (SOD1) mRNA abundance in cells challenged with LPS. Overall, LPS challenge triggered the activation of isolated PMN from mid-lactation cows. However, data suggest the use of a shorter incubation time to capture the peak response and not the resolution of the inflammatory response as in the present study. Our results indicate a possible involvement of Met in modulating PMN inflammatory and oxidative stress status and in helping the resolution of inflammation after initial stimulation.

Evaluation of the optimal standardized ileal digestible threonine:lysine ratio in lactating sow diets.

Camborough PIC sows (n = 291) were fed 1 of 5 dietary treatments to evaluate the standardized ileal digestible (SID) Thr:Lys requirement during lactation. Sows were blocked by parity (1, 2, and 3+) and randomly allotted to 1 of 5 SID Thr:Lys ratios (52, 60, 68, 76, and 84). SID Lys was formulated to 1.03% and SID methionine and cystine (M + C):Lys was 55%. Sows were allowed 5.45 kg feed/day starting on the day of farrowing. All other nutrients met or exceeded the NRC (2012) requirements. Sows were allowed ad libitum access to water, and piglets were cross-fostered within treatment within 24 h of birth. Data collected during the study included sow prefarrow BW, sow weaning weight, starting litter weight, weaning litter weight, piglet mortality, weaning-to-estrus interval, and subsequent total born piglets. Data were analyzed as a randomized complete block design using PROC MIXED with sow as the experimental unit and treatment and parity as fixed effects. Requirement estimation models evaluated were quadratic polynomial, broken-line linear, and broken-line quadratic (BLQ) using PROC NLMIXED. Models that differed in their Bayesian information criterion (BIC) values by at least 2 points were considered to have meaningful differences in their data fit. The best-fit model was based on the best BIC value. As the SID Thr:Lys ratio increased, there was a quadratic response on ADFI (4.73, 4.57, 4.67, 4.55, and 4.60 kg/d; P = 0.001) and percent of sow BW loss (-6.4, -7.89, -7.35, -6.19, and -5.81; P = 0.004). In addition, there was a trend for weaning-to-estrus interval to be affected by the ratio (5.4, 4.4, 4.6, 4.5, and 4.8; P = 0.07). Daily litter gain was also quadratically improved as the SID Thr:Lys ratio increased (2.67, 2.67, 2.78, 2.77, and 2.68 kg/d; P-value = 0.001). For daily litter gain, the BLQ model was determined to be the best fit with an estimated SID Thr:Lys requirement of 65%. In conclusion, the optimal SID Thr:Lys ratio for litter growth was 65.

Effects of dietary total sulphur amino acids to lysine ratio on performance, nitrogen utilization of Ac layers (black-boned chicken)

A study was conducted to evaluate the effects of dietary total sulphur amino acids (TSAA) to lysine (Lys) ratio on performance of Ac layers (black-boned chicken). A total of 800 laying hens from 38 to 50 weeks old was allocated according to a completely randomized design with five treatments and 20 replicates of 8 birds each. The basal diet was formulated with 16% crude protein (CP), 2755 kcal/kg of metabolizable energy (ME), 0.482% methionine, 0.925% TSAA and 1.12% lysine. The TSAA/Lys ratio of the basal diet was 0.85. The basal diet plus four diets were formulated, two with TSSA levels at 10% and 20% below and two at 10% and 20% above that of the basal diet, giving 0.762%, 0.857%, 1.047% and 1.142% TSAA, respectively with the basal at 0.925% TSAA. The 10% decrease or increase in TSAA from 0.952% did not affect feed intake or egg production. However, further TSAA decreases from 0.857% to 0.762% led to reducing egg weight, which increased with a curvilinear trend as the level of TSAA in the diets was increased. TSAA influenced nitrogen retention in a quadratic trend, with hens fed diets containing 0.952% and 1.047 % TSAA retaining more nitrogen than the other treatments. Increasing dietary TSAA increased the white and yolk index and Haugh unit, whereas egg shell thickness, yolk colour and egg components were not influenced. The TSAA/Lys ratio of 0.85 improved egg weight and nitrogen retention of Ac layers. Keywords: Egg weight, feed intake, performance, production, nitrogen retention, sulphur amino acid

The optimum valine: lysine ratios on performance and carcass traits of male broilers based on different regression approaches

ABSTRACTThree different regression approaches were applied to determine the optimal digestible (d.) and analyzed Val:Lys ratios for broiler performance and carcass yield. One-day-old male Cobb 500 broilers (n = 960) were assigned to 1 of 8 diets, with 6 pens/diet and 20 birds/pen, for 42 days. The negative control consisted of the basal diet with a d.Val:d.Lys ratio of 0.63 and with 93% of the required d.Lys. The positive control consisted of the basal diet with a d.Val:d.Lys of 0.80, with no reduction in d.Lys content. The other (test) diets contained a range of d.Val:d.Lys ratios, all with 93% of the required d.Lys. Data on feed intake (FI), body weight gain (BWG), and feed conversion ratio (FCR) were submitted to regression analysis, applying quadratic polynomial (QP), exponential asymptotic (EA), and linear response plateau (LRP) models. Since Val did not affect carcass or breast meat yield, no regression was performed. Digestible and analyzed Val:Lys ratios were similar based on the regression models. The intercept between the QP and LRP models was used to determine the optimum Val:Lys ratio. Overall, the ideal d.Val:d.Lys ratio will vary according to the main goal of poultry production, i.e., BWG or FCR. For BWG, the ideal ratio was found to be 0.78 (0 to 12 d), 0.73 (0 to 28 d), and 0.76 (0 to 35 or 0 to 42 d). For FCR, the optimum d.Val:d.Lys was found to be 0.80 (0 to 12 d), 0.75 (0 to 28 d), and 0.78 (0 to 35 or 0 to 42 d). The optimum analyzed Val:Lys ratio was slightly higher. For instance, for BWG the optimum ratio was 0.80 (0 to 12 d), 0.76 (0 to 28 d), and 0.79 (0 to 35 or 0 to 42 d). For FCR, the optimum Val:Lys was 0.81 (0 to 12 d), 0.79 (0 to 28 d), and 0.81 (0 to 35 or 0 to 42 d). Valine did not affect carcass or breast meat yield.

METHIONINE PLUS CYSTINE TO LYSINE RATIO IN DIETS FOR TAMBAQUI JUVENILES

ABSTRACT The objective of this study was to determine the appropriate ratio of methionine plus cystine to lysine in rations for tambaqui (Colossoma macropomum) juveniles, with initial weights of 0.28 ± 0.08 g and 0.94 ± 0.33 g. A randomized block design consisting of six treatments, five replicates in two blocks, and 20 fish per replicate was implemented. Six isolisinic (1.45%), isoenergetic, isophosphoric, and isocalcic diets, containing different ratios of methionine plus cystine to digestible lysine (50%, 55%, 60%, 65%, 70%, and 75%) were used. Performance and feed efficiency variables, including body composition (moisture, protein, and fat), daily protein deposition rate, daily fat deposition rate, and nitrogen retention efficiency, were evaluated. The specific growth rate and feed conversion presented quadratic effects, with maximum effects from the digestible methionine plus cystine to lysine ratio of 64.4% and 64.8%, respectively. The increase in digestible methionine plus cystine intake resulted in a linear reduction in body fat content with the elevation of the digestible methionine plus cystine to lysine ratio. The digestible methionine plus cystine to lysine ratio recommended in rations for tambaqui fingerlings is 64.8%.

Evaluating the effect of yeast cell wall supplementation on ideal threonine to lysine ratios in broilers as measured by performance, intestinal mucin secretion, morphology, and goblet cell number

SUMMARY The objective of this study was to investigate whether or not a prebiotic yeast cell wall (YCW), previously shown to improve performance in challenge studies, affects threonine requirements of broilers. Gain, F/G, intestinal morphology, mucin secretion, and goblet cell (GC) number per villi were measured. A total of 240 1-d-old Ross 308 broiler chickens were distributed in 2 Petersime battery brooder units (48 pens; 5 birds per pen). Birds were fed for a 21-d trial with different threonine to lysine ratios (0.65, 0.70, and 0.75) with and without YCW at 250 ppm. A basal diet with 22% protein and 2,980 Kcal/kg ME was used for the dietary treatments. The calculated lysine concentration was 1.35%, while threonine was 0.88%, 0.95%, and 1.02%, respectively. Birds and feed were weighed by pen, and the weights recorded at days 0, 7, 14, and 21 of the experiment for general performance data. At day 21, samples from excreta and small intestine (jejunum and ileum) were collected. YCW did not show any significant effect with respect to the variables evaluated in this non-challenge study. There was no significant effect for threonine to lysine ratios for all performance variables that had been measured throughout the study. With respect to intestinal morphology, there were significant increases in main effects for the threonine to lysine ratio 0.75 compared with 0.65 in mucin secretion, GC, and jejunum VW, while the jejunum VH significantly increased compared with threonine to lysine ratio 0.70.

Pigs receiving daily tailored diets using precision-feeding techniques have different threonine requirements than pigs fed in conventional phase-feeding systems

BackgroundThere is large variation in amino acids requirements among pigs, hence feeding pigs individually with daily tailored diets or in groups with a single feed may require different levels of nutrients. Thus, the response to different threonine levels (70%, 85%, 100%, 115%, and 130% of the ideal threonine:lysine protein ratio of 0.65) was studied in growing pigs raised in a conventional group phase-feeding (GPF) system or fed individually using individual precision-feeding (IPF) techniques. In a 21-day trial, 110 barrows (25 ± 0.80 kg body weight) were housed in the same room and fed using electronic feeders. Five pigs per treatment were slaughtered at the end of the trial.ResultsThreonine intake increased linearly for the IPF and GPF pigs (P < 0.05). Lysine intake was similar across the treatments. Average daily gain, gain:feed ratio, and protein deposition were affected linearly by threonine level (P < 0.05) in both feeding systems. Protein deposition in the GPF pigs was maximized at 150 g/d and a 0.65 threonine:lysine ratio, whereas protein deposition increased linearly in the IPF pigs. Plasma Met and serine levels were 11 and 7% higher, respectively, in the IPF pigs than in the GPF pigs (P < 0.05). Dietary threonine increased (P < 0.05) threonine concentration in the longissimus dorsi in a quadratic manner in the IPF pigs, whereas there was no effect in the GPF pigs. Longissimus dorsi collagen decreased as dietary threonine increased in the IPF and GPF pigs (P < 0.10). Carcass muscle crude protein was 2% higher in the GPF pigs than in the IPF pigs (P < 0.05).ConclusionsIndividual pigs are able to modulate growth and the composition of growth according to threonine intake. The average amino acid ratio value that is currently used for GPF cannot be used for IPF.

The response of performance in grower and finisher pigs to diets formulated to different tryptophan to lysine ratios

Three experiments were conducted to determine the optimal dietary standardized ileal digestible (SID) Trp to Lys ratio (Trp:Lys) for grower-finisher pigs with body weight of 20–50 (Experiment (Exp.) 1), 50–80 (Exp. 2), and 80–110 kg (Exp. 3). A total of 4032 Duroc × Yorkshire × Landrace barrows and gilts were used in the experiments with a randomized complete blocked design. For each experiment, 1344 pigs were randomly assigned into 6 dietary treatments (SID Trp:Lys levels: 0.150, 0.165, 0.180, 0.195, 0.210, and 0.225) with 8 replicate pens per treatment (14 barrows and 14 gilts per pen). Synthetic Trp was used to adjust the dietary SID Trp:Lys, while the Lys content in all 6 diets remained fixed in each experiment. In Exp. 1, the average daily gain (ADG), average daily feed intake (ADFI), gain to feed ratio (G:F), and serum urea N (SUN) were increased quadratically (P < 0.01) as the SID Trp:Lys increased from 0.150 to 0.225. The optimal SID Trp:Lys for ADG estimated using broken-line and curvilinear-plateau models were 0.171 and 0.188, respectively. For G:F, the break-points were 0.192 and 0.207 for the linear and quadratic models, respectively. In Exp. 2, a quadratic increase was observed in ADG, ADFI, G:F, and SUN as the SID Trp:Lys increased from 0.150 to 0.225 (P < 0.05). The optimal SID Trp:Lys for ADG estimated using the broken-line and curvilinear-plateau models were 0.183 and 0.200, respectively. The break-points for G:F estimated using broken-line and curvilinear-plateau models were 0.195 and 0.213, respectively. In Exp. 3, the ADG, G:F, and SUN increased quadratically with increasing SID Trp:Lys, while ADFI increased linearly (P < 0.05). The optimal SID Trp:Lys for ADG estimated using the broken-line and curvilinear-plateau models were 0.184 and 0.201, respectively. Likewise for G:F, the best ratios were 0.174 and 0.198 for the linear and curvilinear models, respectively. In summary, the optimal Trp:Lys for ADG estimated using the broken-line model in pigs weighing 20 to 50, 50 to 80, and 80 to 110 kg were 0.171, 0.183, and 0.184, respectively. The optimal Trp:Lys for G:F estimated using the broken-line model in pigs weighing 20 to 50, 50 to 80, and 80 to 110 kg were 0.192, 0.195, and 0.174, respectively.

Determination of the optimum arginine : lysine ratio in broiler diets

The study was conducted to determine the optimum dietary concentration of arginine relative to lysine on the basis of the performance, carcass traits and blood characteristics of 1–35-day-old broilers using a randomised complete block design. One-day-old broilers (n = 1200) were allocated to five dietary treatment groups receiving different arginine:lysine (Arg:Lys) ratios, where the proportion of Arg was progressively increased by increments of 10%, and the concentration of lysine was kept constant; the final ratios were 0.85, 0.95, 1.05, 1.16 and 1.26. Each diet treatment was composed of eight replicates (4 males and 4 females), with 30 chickens each replicate. All broilers were fed in three phases, namely starter, grower and finisher, at 1–10, 11–24 and 25–35 days of age respectively. An increase in the Arg:Lys ratio in the diet from 0.85 to 1.26 linearly (P &amp;lt; 0.001) increased bodyweight gain by 7% and improved feed conversion ratio by 6%. Feed intake and mortality were not significantly (P &amp;gt; 0.05) different among the treatments. Increasing the Arg:Lys ratio in the diet linearly (P &amp;lt; 0.0001) and quadratically (P &amp;lt; 0.05) improved the carcass yield and relative chilled carcass weight respectively. The percentages of breast meat and creatinine and insulin-like growth factor-1 concentrations also linearly (P &amp;lt; 0.0001) increased by 5.5%, 23.0% and 18.0% respectively, with an increasing dietary Arg:Lys ratio. The results of the present study indicated that the highest dietary Arg:Lys ratio (1.26) improved bodyweight gain, feed conversion ratio, breast meat, creatinine and insulin-like growth factor-1. However, the optimum dietary Arg:Lys ratio to improve carcass yield and weight gain in the grower phase (Days 11–24 of age) was at 1.05.