Increasing Standardized Ileal Digestible Lys Research Articles

25 Effects of dietary standardized ileal digestible lysine on growth performance, carcass characteristics, and economics of pigs from 100 to 130 kg

Abstract A total of 1,570 finishing pigs (337 × 1050, PIC; initially 103.4 ± 0.85 kg) were used in a 28-d trial to determine the effects of feeding increasing standardized ileal digestible (SID) Lys to pigs between 100 to 130 kg on growth performance, carcass characteristics, and economics. Before the beginning of the study, the 3 heaviest pigs per pen were removed and marketed with all remaining pigs marketed 28-d later at the end of the study. Pigs were housed in mixed sex pens, with 20 pigs per pen and 20 pens per treatment. The experiment was a randomized complete block design with four dietary treatments: 0.63, 0.68, 0.75, and 0.82% SID Lys. Diets were corn-soybean meal-based and fed in meal form. Dietary treatments were similar in NE and increasing SID Lys was achieved by increasing soybean meal and feed grade amino acids. For the first 14 d from 100 to approximately 118 kg, there was a linear tendency for increased (P = 0.074) average daily gain (ADG), a linear improvement (P < 0.05) in gain to feed ratio (G:F), and increase (P < 0.001) in SID lysine intake per kg of gain as SID Lys increased (Table). For the second 14 d from 118 to 128 kg, SID Lys intake per kg of gain increased (P < 0.001) as SID Lys increased, however; there was no evidence for difference (P > 0.10) for any growth performance traits. Overall, there was a linear increase (P = 0.018) in G:F and increase (P < 0.001) in SID lysine intake per kg of gain as SID Lys increased. Increasing SID Lys also linearly increased (P < 0.05) percentage lean and decreased (P < 0.05) backfat depth with no evidence for differences (P > 0.10) in other carcass criteria. For economics, feed cost and feed cost per kg of gain linearly increased (P < 0.05) as SID Lys increased in both low and high-price scenarios. Income over feed cost linearly decreased (P < 0.05) as dietary SID Lys increased in a low-price scenario, but there was no difference between treatments in a high-price scenario (P > 0.10). In conclusion, increasing dietary SID lysine in the last 28-d of the finisher period linearly increased G:F and SID Lys intake per kg of gain without significantly influencing other growth performance traits. Feed cost per kg of gain was linearly increased for both low and high-price scenarios with a detriment for IOFC with increasing SID Lys in the low-price scenario.

11 The effect of increased standardized ileal digestible lysine through increased soybean meal during late gestation on lactating sow and litter performance

Abstract A total of 87 sows (Line 241, DNA) and their offspring were used to evaluate the effect of increasing standardized ileal digestible (SID) lysine through increasing soybean meal (SBM) concentration in late gestation diets on lactating sow and litter performance. Sows were blocked by parity and body weight (BW) on approximately d 90 of gestation and allotted to 1 of 3 treatments with 29 replications per treatment. Diets included increasing SID lysine (0.60, 0.80, or 1.00%) through increased SBM (14, 21, or 29% of the diet). Sows received approximately 2.04 kg/d of their treatment diet for an average SID Lys intake of 11.9, 15.8, or 19.9 g/d, respectively. Diets were fed from d 90 of gestation until farrowing. After farrowing, all females were fed a common lactation diet containing 1.10% SID Lys until weaning (19 d post-farrow). Sow BW, caliper score, and backfat and loin depth were collected on d 90, upon entry into the farrowing house (d 110), and at weaning. Urine samples were collected on d 90 and 110 of gestation to ascertain urinary creatinine concentrations. Litters were cross-fostered within sow treatment by 48 h after farrowing to equalize litter size. Parity was included in the statistical model as a fixed effect with females being classified as either a primiparous (n = 35) or multiparous (n = 52) sow. Body weight gain from d 90 to 110 of gestation increased as SID Lys increased (linear, P < 0.001; Table). There were no differences in starting litter size or piglet birth weight with increasing SID Lys in late gestation (linear, P > 0.10). Change in urinary creatinine level from d 90 to 110 of gestation tended to decrease as SID Lys increased in the diet (linear, P = 0.063) suggesting that less muscle catabolism occurred with increasing SID Lys. Piglet average daily gain (ADG) from d 2 to 10 of lactation linearly increased as SID Lys increased (P = 0.017), but not from d 2 to weaning. From d 2 until weaning, litters from sows fed the 0.80% SID Lys gestation diet had the greatest litter gain (quadratic, P = 0.044). Pre-weaning mortality from birth until d 2 of lactation was greatest for sows fed 0.80% SID Lys (quadratic, P = 0.025). There was a parity × gestation diet interaction for pre-weaning mortality from d 2 to weaning (P = 0.049) where mortality increased as SID Lys increased in primiparous sows but decreased in multiparous sows. In conclusion, increased SID Lys through increased SBM linearly increased late gestation sow BW gain and piglet ADG during the first portion of lactation. However, litters from sows on the 0.80% SID Lys treatment exhibited the highest litter ADG during late lactation and overall.

141 Determination of the optimum standardized ileal digestible lysine for nursery pigs fed high levels of dietary fiber

Abstract An experiment was conducted to determine the optimum standardized ileal digestible (SID) Lys for nursery swine-fed high levels of dietary fiber. A total of 2,525 pigs [PIC 337 × 1050, initial body weight (BW) = 6.5 kg], placed in pens of 36 mixed-sex pigs, were used in a 42-d trial. Pigs were allotted to 1 of 5 dietary treatments with 14 replicates per treatment. Increasing dietary SID Lys concentrations of 1.14, 1.22, 1.30, 1.38, and 1.45% were obtained by blending the 1.14% and the 1.45% SID Lys diets via Big Dutchman DryExact Pro feeding system (Big Dutchman, Holland, MI). The different SID Lys levels were obtained by changing the inclusion rate of soybean meal, which ranged from 15 to 28%. The experimental diets contained sugar beet pulp and soy hulls, resulting in an NDF level of 10.5%. Experimental diets were fed for 17 d and followed by a common corn, soybean meal, and 10% DDGS diet with 1.30% SID Lys from d 17 to 42. Pigs were weighed on d 0, 17, and 42 to calculate average daily gain (ADG), average daily feed intake (ADFI) and gain to feed ratio (G:F). From d 0 to 17, a quadratic (P < 0.05) improvement in ADG and ADFI was observed for pigs fed increasing SID Lys up to 1.38%, plateauing thereafter. Pigs fed increasing SID Lys had linearly (P = 0.001) improved G:F (Table 1). From d 17 to 42, there was no evidence (P > 0.10) for differences in ADG, yet ADFI increased linearly (P = 0.004) while G:F decreased linearly (P = 0.001) for pigs previously fed increasing concentrations of SID Lys. Overall (d 0 to 42) for pigs fed increasing SID Lys, ADG and ADFI increased quadratically (P < 0.05) up to 1.38% SID Lys, whereas G:F increased linearly (P = 0.001) up to 1.45% SID Lys. Mortality and removal rate was quadratically influenced (P < 0.05) by feeding increasing SID Lys. Our findings suggest feeding weaned pigs from d 0 to 17 a diet containing 1.38% SID Lys is optimal for growth performance while minimizing mortality and removal rate.

208 Effect of SID LYS Level with Constant Non-Essential Amino Acids

Abstract Many investigations on the effect of low protein diets reduce crude protein (CP) and have a constant standardized ileal digestible (SID) LYS resulting in reductions in ADG, ADFI, and gain:feed is some cases. This experiment was conducted to determine the impact of maintaining constant non-essential amino acids and changing SID LYS and other essential amino acids. For the experiment, 288 pigs (~22 d of age, 6.61 ± 0.95 kg, 8 replicates/treatment, 6 pigs/pen) were stratified by body (BW) and randomly allotted to one of 6 treatments in a randomized complete block design. Non-essential amino acids were fixed in all diets and synthetic amino acids were added to increase SID LYS from 1.15% to 1.4% while maintaining constant ratios of MET+CYS, THR, TRP, VAL, and ILE to LYS. Diets were corn, wheat, barley, and soy based with 1.1% corn starch in the least SID LYS diet. Synthetic amino acids were added to the diet at the expense of corn starch to maintain non-essential amino acid levels. The CP ranged from 17.8% when SID LYS was 1.15% and 18.6% when SID LYS was 1.4%. Experimental diets were fed for 21 d. Body weight, feed disappearance, visual fecal scores, and visual piglet scores were measured. Visual fecal scores (1 = normal to 4 = watery) and visual pig appearance scores (1 = pale and hairy to 4 = normal color and well-rounded muscle) were assessed on ordered likert scales to determine the probabilities of observing a more normal stool quality and a worse visual appearance, respectively. Performance data were analyzed as a general linear model. Stool quality and visual appearance were analyzed as a generalized linear mixed model. Contrasts were used to test linear and quadratic effects of dietary SID LYS. Results of the experiment are presented in Table 1. Increasing SID LYS with constant non-essential amino acids did not affect ADG or BW. The ADFI was linearly decreased (P < 0.1) and gain:feed was linearly increased (P < 0.0001) with increasing SID LYS (Table 1). Stool quality was not affected. Visual appearance of the pigs was quadratically affected (P < 0.05) by changing SID LYS. Pigs that had consumed diets with the lowest or highest SID LYS had the best visual appearance (lowest probability). The results of the current experiment differ suggest SID LYS may regulate feed intake and nutrient efficiency, but BW gain is not affected when non-essential amino acids are held constant. This differs from cases where CP is reduced, which results are decreased growth in many cases.

130 Effects of Increasing Dietary Standardized Ileal Digestible Lysine Levels on Growth Performance of 102- to 127-kg Immunocastred Gilts and Boars

Abstract Our objective was to determine the effects of increasing dietary standardized ileal digestible (SID) lysine (Lys) on growth performance of immunocastrated gilts and boars. A total of 3,519 split gender pigs [PIC 337×Camborough, initial body weight (BW) = 101.7 ± 3.89 kg] were used in a 21-d trial in 2 replicates. Following the immunization against gonadotropin-releasing hormone (administrated with Vivax, Zoetis, São Paulo, SP, Brazil) in both genders, pens of pigs were weighed, blocked by BW, and randomly allotted to 1 of 5 treatments. Treatments consisted of 1.69, 1.90, 2.11, 2.32, and 2.53 g of SID Lys:Mcal of ME, which corresponded to 80, 90, 100, 110, and 120% of PIC SID Lys recommendations for mixed gender between barrow and gilts. This resulted in 0.56, 0.63, 0.70, 0.77, and 0.84% SID Lys given that the treatment diets were corn-soybean-meal-based and contained 3,300 Kcal of ME/kg. There were 6 split gender pens∙treatment-1∙replicate-1 and 29 pigs/pen. Data were analyzed using generalized linear and nonlinear mixed models with a pen as the experimental unit. Competing models included linear, quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ). There was no evidence of linear or quadratic SID Lys concentration by gender interaction (Table). Increasing SID Lys concentration improved average daily gain (ADG; quadratic, P < 0.01) and gain-to-feed ratio (G:F; quadratic, P < 0.01). The QP, BLL, and BLQ had a similar fit for the ADG and G:F. In the QP model, 95% and 100% of the ADG were achieved at 0.64 and 0.76% of SID Lys, respectively, and at 0.61 and 0.75% for G:F. The BLL and BLQ models estimated the breakpoint at 0.70% (95% CI: 0.65-0.74%) and 0.68% SID Lys (95% CI: 0.50-0.85%), for ADG, respectively. For G:F, the BLL, and BLQ models estimated the breakpoint at dietary SID Lys of 0.69% (95% CI: 0.52-0.86%) and 0.68% (95% CI: 0.58-0.78%), respectively. There was no evidence that increasing dietary SID Lys levels impacted the average daily feed intake or the removal and mortality rate. In the current trial the estimated optimum SID Lys:Mcal of ME ratio for 102- to 127-kg immunocastrated gilts and boars ranged from 2.06-2.30 (0.68-0.76% SID Lys based on a 3,300 kcal of ME/kg diet), depending on the statistical model.

Reducing dietary crude protein in broiler diets does not compromise performance and reduces environmental impacts, independently from the amino acid density of the diet

The objective of the present experiment was to investigate the influence of dietary CP, standardized ileal digestible ( SID) Lys level and their interaction in male Ross 308 broilers. From day 10, six experimental treatments were tested until day 35. The six experimental treatments consisted in a 3 × 2 factorial design with 3 levels of dietary SID Lys/CP (equaivalent to 3 levels of dietary CP) and 2 levels of dietary SID Lys. Growth performance, uniformity, carcass traits, litter quality, blood & gut parameters, nitrogen ( N ) emissions and global warming potential ( GWP ) were measured or calculated. There was no interaction for all criteria except for NH 3 and N 2 O volatilization. The increase of dietary SID Lys/CP did not affect growth performance or uniformity, increased abdominal fat yield, decreased all N related parameters (litter N, blood uric acid, N excretion, NH 3 and N 2 0 volatilization). There was an interaction between dietary CP and AA origin for GWP; GWP was further reduced after CP reduction when using AA from EU. Increasing SID Lys improved growth performance, increased uniformity, increased breast meat yield, reduced abdominal fat yield, but increased N emissions and GWP. This study indicates that dietary CP can be drastically reduced in different nutritional contexts without negatively affecting growth performance, and with positive benefits on the environment.

Effects of standardized ileal digestible lysine level on growth performance and economic return for 18 to 128 kg Duroc-sired pigs.

The recent shift of the U.S. swine industry toward improved pork quality, such as color, marbling, and firmness, has led to increased use of Duroc-sired pigs in the marketplace. Our objective was to determine the standardized ileal digestible (SID) Lys requirement estimates for Duroc-sired (600 × 241, DNA, Columbus, NE) pigs from 18 to 128 kg BW. We conducted a series of experiments using corn-soybean meal-based diets with pigs allotted to 6 or 7 treatments in randomized complete block designs. In all experiments an equal number of barrows and gilts were used within a pen. In experiment 1, 300 pigs (initially 18.4 ± 0.50 kg) were used with 5 pigs per pen and 10 pens per treatment with 6 SID Lys levels from 1.00% to 1.50%. Increasing SID Lys increased (linear, P < 0.040) final BW, ADG, G:F, and Lys intake/kg of gain, and decreased (linear, P = 0.012) ADFI. In experiment 2, 608 pigs (initially 36.3 ± 0.91 kg) were used with 7 to 9 pigs per pen and 12 pens per treatment with 6 SID Lys levels from 0.80% to 1.20%. Increasing SID Lys increased (linear, P ≤ 0.036) ADG, G:F, and Lys intake/kg of gain. In experiment 3, 700 pigs (initially 53.2 ± 0.86 kg) were used with 8 to 10 pigs per pen and 12 pens per treatment with 6 SID Lys levels from 0.65% to 1.00%. Increasing SID Lys increased (linear, P < 0.001) final BW, ADG, and Lys intake/kg of gain, decreased (quadratic, P = 0.004) ADFI, and improved (quadratic, P < 0.001) G:F. In experiment 4, 616 pigs (initially 76.4 ± 1.25 kg) were used with 8 to 10 pigs per pen and 5, 6, or 11 pens per treatment with 7 SID Lys levels from 0.58% to 1.00%. Increasing SID Lys increased (linear, P ≤ 0.022) ADG, Lys intake per kilogram of gain, and G:F. In experiment 5, 679 pigs (initially 103.8 ± 1.32 kg) were used with 8 to 10 pigs per pen and 11 or 12 pens per treatment with 6 SID Lys levels from 0.43% to 0.78%. Increasing SID Lys increased (linear, P ≤ 0.043) final BW, ADG, and Lys intake per kilogram of gain, and improved (quadratic, P ≤ 0.032) G:F. Using results from all experiments, the quadratic equation of Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0002611 × BW2 - 0.0711037 × BW + 7.284 was developed to reflect the requirement for maximal growth performance from 18 to 128 kg BW. Maximal income over feed cost (IOFC) is best described by the quadratic equation: Lys:calorie ratio, g of SID Lys/Mcal of NE = 0.0001558 × BW2 - 0.04030769 × BW + 5.410. These data provide updated SID Lys estimates for Duroc-sired grow-finish pigs.

158 Effects of Increasing Dietary Standardized Ileal Digestible Lysine Levels on Growth Performance of Grow-Finish Pigs That Were Sired by PIC 800 Boars

Abstract A total of 1,092 pigs (PIC 800 × Camborough) were used to investigate the effects of increasing dietary standardized ileal digestible (SID) Lys on growth performance in 4 experiments covering body weight ranges of 25-45 kg (Exp. 1), 45-73 kg (Exp. 2), 74-91 kg (Exp. 3), and 98-120 kg (Exp. 4). Pigs were placed in 1 room and divided into 2 groups with 42 pens/group and 13 pigs/pen (6 or 7 gilts and 7 or 6 barrows, balanced among treatments). Group 1 was used in Exp. 1 and 3; group 2 was used in Exp. 2 and 4. At the beginning of each trial, on-trial pens were blocked by body weight and randomly allotted to one of 6 treatments (85.0, 90.0, 95.0, 100.0, 107.5, or 115.0% of PIC SID Lys recommendations) in a randomized complete block design. Data were analyzed using generalized linear and nonlinear mixed models with pen as the experimental unit. In Exp. 2 to 4, the competing nonlinear models did not fit the data or improve the fitness compared with the linear models. Greater SID Lys linearly increased (P &amp;lt; 0.05) average daily gain in Exp. 1 and 3 (Table 1). Increasing SID Lys tended to increase gain to feed ratio (G:F; quadratic, P &amp;lt; 0.10) in Exp. 1, and broken-line linear and broken-line quadratic models estimated the maximum G:F at 99.9 and 98.5% SID Lys, respectively. In Exp. 2 and 3, increasing SID Lys also increased G:F (linear, P &amp;lt; 0.10). Growth performance did not differ among treatments in Exp. 4. Results indicated that the optimum SID Lys concentration for 25 to 45 kg PIC 800 pigs was between 98.5 and 99.9% of PIC SID Lys recommendations. More research is needed to validate the optimum SID Lys concentrations for pigs above 45 kg.

144 Effects of Increasing Dietary Standardized Ileal Digestible Lysine Levels on Growth Performance of 15- to 23-Kg Maternal Barrows

Abstract Our objective was to determine the effects of increasing dietary standardized ileal digestible (SID) lysine (Lys) on growth performance of late nursery pigs. A total of 1,125 barrows (L02 ′ L03, initially 15.4 kg ± 0.003) were used in a 14-d study. Pens of pigs were weighed, blocked by location in the barn, and randomly allotted to 1 of 6 treatments that contained 1.05, 1.16, 1.23, 1.29, 1.39, and 1.52% of dietary SID Lys. Diets were corn-soybean meal-based and contained 3,300 Kcal of ME/kg, with treatments achieved by increasing the inclusion of synthetic lysine. There were 9 pens per treatment and 25 barrows per pen. Data were analyzed using generalized linear and nonlinear mixed models with pen as the experimental unit. Competing models included linear, quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ). Increasing SID Lys concentration improved average daily gain (ADG; linear, P &amp;lt; 0.05) and gain to feed ratio (G:F; quadratic, P &amp;lt; 0.05). Although no model provided better fit to the ADG data compared with the linear model, the greatest improvement in growth rate was observed as SID Lys increased from 1.05 to 1.41%. The best-fitting models for G:F were QP and BLL. The QP and BLL models estimated the plateau or breakpoint at dietary SID Lys of 1.45% (95% CI: 1.21 to &amp;gt;1.52%) and 1.41% (95% CI: 1.40 to 1.42%), respectively. There was no evidence that increasing dietary SID Lys levels impacted average daily feed intake or the removal and mortality rate (P &amp;gt; 0.10). Increasing SID Lys concentration increased (linear; P &amp;lt; 0.05) the grams of SID Lys intake per kg of gain. In the current trial, the estimated optimum SID Lys concentration for 15- to 23-kg maternal barrows ranged from 1.41 to 1.46%, depending on the statistical model.

143 Effects of Increasing Dietary Standardized Ileal Digestible Lysine Levels on Growth Performance of 13- to 23-Kg Pigs Sired by PIC 800 Boars

Abstract An experiment was conducted to determine the effects of increasing dietary standardized ileal digestible (SID) Lys on growth performance of late nursery pigs. A total of 546 pigs (PIC 800 × Camborough, initially 12.6 ± 0.56 kg) were used in a 21-d trial. Pens of pigs were weighed, blocked by body weight, and randomly allotted to 1 of 6 treatments that contained 1.10, 1.16, 1.23, 1.29, 1.39, or 1.49% SID Lys (corresponding to 85.0, 90.0, 95.0, 100.0, 107.5, or 115.0% of PIC SID Lys recommendations). Diets were corn-soybean meal-based and contained 2,450 kcal/kg net energy (NE). There were 7 pens/treatment and 13 pigs/pen (6 or 7 gilts and 7 or 6 barrows, balanced among treatments). Data were analyzed using generalized linear and nonlinear mixed models with pen as the experimental unit. Competing models included linear, quadratic polynomial, broken-line linear (BLL), and broken-line quadratic (BLQ). Increasing SID Lys concentration increased average daily gain (ADG; quadratic, P = 0.05) and gain to feed ratio (G:F; linear, P &amp;lt; 0.05; Table 1). Although the best fitting model for G:F was linear, the greatest improvement in efficiency was observed as SID Lys increased from 1.10 to 1.23%. The best-fitting models for ADG were BLL and BLQ. The BLL and BLQ models estimated the breakpoint of SID Lys at 1.26% (95.4% of PIC SID Lys recommendation; 95% CI: 1.17 to 1.29%) and 1.23% (95.0% of PIC SID Lys recommendation; 95% CI: 1.18 to 1.28%), respectively. There was no evidence that increasing dietary SID Lys levels impacted average daily feed intake or the removal and mortality rate. In the current trial with dietary NE at 2,450 kcal/kg, the estimated optimum SID Lys concentration for 13 – 23 kg pigs sired by PIC 800 boars ranged from 1.23 to 1.26%, depending on the statistical model.

142 Effects of Increasing Dietary Standardized Ileal Digestible Lysine Levels on Growth Performance of 11- to 25-Kg Pigs Sired by PIC 337 High Index Boars

Abstract Our objective was to determine the effects of increasing dietary standardized ileal digestible (SID) lysine (Lys) on growth performance of late nursery pigs. A total of 1,116 pigs (PIC 337×Camborough, initially 11.1±0.11 kg) were used in a 21-d study. The pigs were sired by boars ranked in the top 15% of a selected PIC elite boar stud based on index. Pens of pigs were blocked by body weight and randomly allotted to 1 of 5 treatments that contained 1.13, 1.26, 1.32, 1.38, and 1.51% of dietary SID Lys (corresponding to 90, 100, 105, 110, and 120% of PIC SID Lys recommendations). Diets were corn-soybean meal-based and contained 2,385 Kcal of NE/kg. There were 9 mixed gender pens per treatment and 24 or 25 pigs per pen. Data were analyzed using generalized linear and nonlinear mixed models with pen as the experimental unit. Competing models included linear, quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ). Increasing SID Lys concentration improved average daily gain (ADG, linear, P = 0.001) and gain to feed ratio (G:F, quadratic, P = 0.011, Table 1). Although the best fitting model for ADG was the linear, the greatest improvement was observed as SID Lys level increased from 1.13 to 1.32%. The best-fitting models for G:F were BLL, BLQ, and QP. The BLL and BLQ models estimated the breakpoint at 1.31% (95% CI: 1.24 to 1.37%) and 1.30% (95% CI: 1.24 to 1.37%), respectively. The QP model estimated the maximum G:F at 1.44% (95% CI: 1.35 to &amp;gt;1.51%), with 98.7% of maximum G:F achieved at 1.30%. Increasing dietary SID Lys levels marginally reduced removal and mortality rate (linear, P = 0.061). In conclusion, the estimated optimum SID Lys concentration for 11- to 25-kg pigs sired by high index boars ranged from 1.30 to 1.44%, depending on the response criteria and statistical model.

145 Effects of Increasing Dietary Standardized Ileal Digestible Lysine Levels on Growth Performance of 12- to 23-Kg Boars and Gilts

Abstract Our objective was to determine the effects of increasing dietary standardized ileal digestible (SID) lysine (Lys) on growth performance of late nursery boars and gilts. A total of 1,920 pigs (PIC 337×Camborough, initially 12.1±1.34kg) were used in a 21-d trial. Pens of pigs were weighed, blocked by body weight, and randomly allotted to 1 of 5 treatments containing 1.10, 1.16, 1.29, 1.42, and 1.48% SID Lys (corresponding to 85, 90, 100, 110 and 115.0% of PIC SID Lys recommendations). Diets were corn-soybean-meal-based and contained 3,300 Kcal of ME/kg. There were 6 split gender pens/treatment and 32 pigs/pen. Data were analyzed using generalized linear and nonlinear mixed models with pen as the experimental unit. Competing models included linear, quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ). There was no evidence of linear or quadratic SID Lys concentration by gender interaction. Increasing SID Lys concentration improved average daily gain (ADG; quadratic, P &amp;lt; 0.05) and gain to feed ratio (G:F; quadratic, &amp;lt; 0.01). The QP, BLL, and BLQ had similar fit for the ADG and G:F. In the QP model, 95% and 100% of the ADG were at 1.18 and 1.36% of SID Lys, respectively, and 1.17 and 1.35% for G:F. The BLL and BLQ models estimated the breakpoint at 1.20% (95% CI: 1.06-1.35%) and 1.22% SID Lys (95% CI: 0.97-1.47%), for ADG, respectively. For G:F, the BLL and BLQ models estimated the breakpoint at dietary SID Lys of 1.20% (95% CI: 1.07-1.33%) and 1.20% (95% CI: 1.03-1.38%), respectively. There was no evidence that increasing dietary SID Lys levels impacted average daily feed intake or the removal and mortality rate. In the current trial with dietary ME level at 3,300 kcal/kg, the estimated optimum SID Lys concentration for 12- to 23-kg boars and gilts ranged from 1.20-1.36%, depending on the statistical model.

Effects of standardized ileal digestible lysine on growth performance and economic return in duroc-sired finishing pigs.

In the United States, emphasis has shifted toward improved pork quality and has resulted in greater use of Duroc-based terminal sires. Duroc sires have differences in ADG, ADFI, G:F, and carcass leanness compared to other sires. Therefore, our objective was to determine the standardized ileal digestible (SID) Lys estimates for Duroc-based sired finishing pigs. In Exp. 1, 2,124 pigs (DNA 600 ×PIC 1050, initially 48.9 kg) were used with 24–27 pigs per pen and 16 pens per treatment. Corn-soybean meal-based diets were fed in three phases (49–59, 59–71, and 71–81 kg). Pens were randomly allotted to 1 of 5 treatments based as a percentage of PIC (2016) SID Lys estimates for gilts (85%, 95%, 103%, 110%, and 120%). Phase 1 diets were formulated to 0.90%, 1.01%, 1.09%, 1.17%, and 1.27%, phase 2 to 0.79%, 0.87%, 0.94%, 1.03%, and 1.10%, and phase 3 to 0.71%, 0.78%, 0.85%, 0.92%, and 0.99% SID Lys. Increasing SID Lys increased (linear, P < 0.001) ADG and Lys intake/kg of gain. A marginally significant improvement (quadratic, P = 0.071) in G:F was observed as SID Lys increased. Feed cost, feed cost/kg of gain, revenue (linear, P < 0.01) and income over feed cost (IOFC) increased (quadratic, P = 0.045) with increasing SID Lys. In Exp. 2, 2,099 pigs (DNA 600 ×PIC 1050, initially 90.1 kg) were used with 24–27 pigs per pen and 20 pens per treatment. Corn-soybean meal-based diets were fed in 2 phases (90–106 and 106–136 kg). Pens were randomly allotted to 1 of 4 treatments based as a percentage of PIC (2016) SID Lys estimates for gilts (85%, 93%, 100%, and 110%). Phase 1 diets were formulated to 0.65%, 0.71%, 0.77%, and 0.84% and phase 2 to 0.60%, 0.66%, 0.71%, and 0.78% SID Lys. Overall, increasing SID Lys increased (linear, P < 0.05) G:F, Lys intake/kg of gain, live weight and HCW, and increased (quadratic, P = 0.020) ADG. Feed cost (linear, P < 0.01), revenue, and IOFC increased (quadratic, P ≤ 0.053) with increasing SID Lys. In conclusion, the SID Lys estimate for growth and IOFC was 1.19% or 4.63 g SID Lys/Mcal of NE, 1.05% or 4.04 g SID Lys/Mcal of NE, and 0.94% or 3.58 g SID Lys/Mcal of NE for pigs weighing 49–59 kg, 59–71 kg, and 71–81 kg, respectively. The SID Lys estimate for late finishing pigs was 0.74%–0.81% or 2.85–3.10 g SID Lys/Mcal of NE, and 0.69%–0.75% or 2.61–2.84 g SID Lys/Mcal of NE, for 90–106 kg and 106–136 kg pigs, respectively. These data provide SID Lys estimates for current Duroc-sired genetic lines raised in a commercial environment.

168 Effects of Increasing Dietary Standardized Ileal Digestible Lysine Levels on Growth Performance of 12- to 26-kg Pigs Sired by High Index Boars

Abstract Our objective was to determine the effects of increasing dietary standardized ileal digestible (SID) lysine (Lys) on the growth performance of late nursery pigs. A total of 1,125 pigs (PIC 337×Camborough, initially 12.0±0.66 kg) were used in a 21-d study. The pigs used in the study were sired by boars ranked in the top 15% of a selected PIC elite boar stud based on index. Pens of pigs were blocked by body weight and randomly allotted to 1 of 5 treatments containing 0.95, 1.10, 1.20, 1.35, and 1.50% of SID Lys. Diets were corn-soybean meal-based and contained 2,480 Kcal of NE/kg. Treatments were achieved with increasing feed-grade amino acids. There were 9 mixed gender pens per treatment and 25 pigs per pen. Data were analyzed using generalized linear and nonlinear mixed models with pen as the experimental unit. Competing models included linear, quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ). Increasing SID Lys concentration improved average daily gain (ADG, linear, P &amp;lt; 0.001) and gain to feed ratio (G:F, quadratic, P = 0.011). The best-fitting models for ADG were QP and BLL. The QP model estimated the maximum ADG at 1.43% (95% CI: 1.12 to &amp;gt;1.50%), with 99% of maximum ADG achieved at 1.27%. The BLL plateau was estimated at 1.31% (95%CI: 1.06 to &amp;gt;1.50%). The best-fitting models for G:F were QP, BLL, and BLQ. The QP model estimated the maximum G:F at 1.48% (95%CI: 1.23 to &amp;gt;1.50%), with 99% of maximum G:F achieved at 1.24%. The BLL plateau was estimated at 1.30% (95% CI: 1.18 to 1.41%), whereas the BLQ plateau was estimated at 1.36% (95%CI: 1.14 to &amp;gt;1.50%). In conclusion, the estimated optimum SID Lys concentration for 12- to 26-kg pigs sired by high index boars ranged from 1.30 to 1.48%, depending on the response criteria and statistical model.

Modeling standardized ileal digestible lysine requirements during gestation on gilts and sows

The objective of this study was to model daily standardized ileal digestible (SID) Lys-requirements in gestating sows. Data from 877 females (459 gilts, 418 sows; Camborough®, PIC, Hendersonville, TN) was collected and modeled using Dourmad et al. (2008) equations. Individual feed intake and body weight (BW) were recorded daily throughout gestation. Dietary treatments included 11, 13.5, 16, and 18.5 g/d SID Lys-intake throughout gestation. Data were divided into 2 parity groups: gilts and sows, and gestation was divided into 3 stages: d 5 to 39 (early), 40 to 74 (mid), and 75 to 108 (late). The model follows the principle that energy is partitioned between maintenance, growth of conceptus (fetus, placenta, and fluids), and maternal protein and lipid deposition. Requirements for SID Lys-were estimated based on predicted whole body protein deposition. After dividing energy requirements into tissue pools for maintenance, products of conceptus, and maternal reserves, the greatest portion of the energy requirement was for maintenance. Estimated protein retention of the conceptus increased in each sequential stage of gestation (P < 0.05) but there were no differences (P > 0.05) among treatments. Regardless of parity or stage of gestation, increasing SID Lys-increased estimated maternal protein deposition (linear, P < 0.001), but it decreased in each sequential stage of gestation (P < 0.001). Estimated maternal lipid deposition increased with increasing SID Lys (linear, P = 0.076) and decreased in each sequential stage of gestation (P < 0.05), with gilts having to mobilize maternal lipid in late gestation. For gilts and sows, estimated SID Lys-requirements increased in each sequential stage of gestation (P < 0.05). Estimated SID Lys-balance (SID Lys-intake - SID Lys-requirement) increased with increasing SID Lys-in the diet (quadratic, P < 0.054), and decreased (P < 0.05) in each sequential stage of gestation. Overall, the model shows how changes in protein retention of the conceptus and maternal protein deposition differ by parity and stage of gestation for a single gestation phase. Based on predicted changes in protein deposition, and SID Lys-balance, providing females with 11.0 g/d SID Lys-throughout gestation adequately meets Lys-requirements for most of gestation; however, gilts and sows were in a negative SID Lys-balance for the last 5- to 10 d of gestation and this can be prevented by providing gilts and sows with 13.5 g/d SID Lys.

78 Evaluation of the growth performance of finishing pigs (Genesus genetics) to titrated levels of dietary lysine

Abstract A total of 1,000 Genesus (Oakville, Manitoba, Canada) genetics pigs (51.8 kg body weight) were used to estimate the standardized ileal digestible (SID) lysine requirement by dietary phase. Pigs were penned by sex at 25 pigs per pen. Pens were allotted to one of five dietary treatments in a completely randomized design with eight replicate pens (four barrow, four gilt) per treatment. Growth performance was evaluated in four independent phases in which pens were re-allotted to dietary treatment between phases. Dietary SID Lys concentrations evaluated were 0.78, 0.88, 0.98, 1.08, and 1.18% for phase 1, 0.68, 0.77, 0.86, 0.95, and 1.04% for phase 2, 0.60, 0.67, 0.75, 0.83 and 0.90% for phase 3, and 0.53, 0.60, 0.67, 0.74, and 0.81% for phase 4. Diets were formulated to be isoenergetic within each phase. During phase 1 (52-64 kg), average daily gain (ADG) and gain to feed ratio (G:F) increased (P &amp;lt; 0.01) quadratically with increasing SID Lys. Breakpoint analysis estimated the SID Lys requirement for ADG and G:F for phase 1 at 0.99 and 1.02%, respectively. During phase 2 (64-82 kg), ADG increased (P &amp;lt; 0.10) quadratically as dietary SID Lys increased with a plateau observed above 0.86% SID Lys. Gain:feed increased linearly (P &amp;lt; 0.01) with increasing SID Lys. During phase 3 (82-97 kg) cost of gain was a quadratic response (P &amp;lt; 0.10) with the breakpoint being at 0.76% SID Lys. During phase 4 (97-131 kg), a linear response (P &amp;lt; 0.02) in G:F was observed with increasing SID Lys but with no improvement above 0.67% SID Lys. These data indicate the SID lysine requirement for Genesus finishing pigs to be approximately 0.99% (23.0 g/d) for 52-64 kg, 0.86% (21.9 g/d) for 64-82 kg, 0.76% (20.2 g/d) for 82-97 kg, and 0.67% (21.6 g/d) 97-131 kg.

202 Determining the effects of increasing dietary standardized ileal digestible lysine levels on growth performance and carcass characteristics of growing-finishing pigs from 29- to 129-kg

Abstract Our objective was to determine the effects of increasing standardized ileal digestible (SID) lysine (Lys) levels on growth performance and carcass characteristics of growing-finishing pigs. A total of 1,013 barrows and gilts (PIC337×Camborough, initially 29.2±0.21 kg) were used in a 112-d growth trial with 25 or 26 pigs per pen and 13 pens per treatment in a randomized complete block design. Diets were corn-soybean meal (SBM)-dried distillers grains with solubles-based, and treatments were achieved through the inclusion of SBM at the expense of corn. Diets were fed in 6 phases and formulated to be iso-caloric within each phase. Treatments consisted of: 1) Low Lys: overall dietary SID Lys levels as 87% of PIC2016 Lys requirement; 2) Medium Lys: overall dietary SID Lys levels as 97% of PIC2016 Lys requirement; 3) High Lys: overall dietary SID Lys levels as 106% of PIC2016 Lys requirement. Experimental data were analyzed using generalized linear mixed models with pen as the experimental unit. Pigs fed High or Medium Lys had greater (P&amp;lt; 0.01) average daily gain compared to pigs fed Low Lys. There was no evidence (P &amp;gt;0.10) for the difference between treatments for average daily feed intake. Pigs fed High Lys had the greatest (P&amp;lt; 0.01) feed efficiency (G:F) followed by Medium Lys, with pigs fed Low Lys with the lowest G:F. Pigs fed High or Medium Lys had greater (P&amp;lt; 0.01) hot carcass weight, loin depth, and lean percentage compared to pigs fed Low Lys. There was no evidence (P &amp;gt;0.10) for treatment effect on carcass yield and backfat. Pigs fed Low Lys had greater removal and mortality rate than those fed High or Medium Lys (P&amp;lt; 0.01). In conclusion, increasing SID Lys over PIC2016 recommendations through increasing SBM levels resulted in increased growth performance and carcass characteristics, and reduced removal and mortality rate of 29- to- 129 kg pigs.

280 Effects of metabolizable energy and standardized ileal digestible lysine levels on lactating sow and litter performance

Abstract The objective was to determine the effects of metabolizable energy (ME) and standardized ileal digestible (SID) lysine (Lys) levels on lactating sows and litter performance. A total of 600 sows (Camborough; PIC, Hendersonville, TN) were blocked by parity (P1, P2, P3+) on d 112 of gestation and allotted to 1 of 6 treatments arranged in a 2 x 3 factorial with the main effect of ME (3.2 and 3.4 Mcal/kg) and SID Lys (0.70, 0.85, and 1.00 %). Corn-soybean meal-based diets were fed from farrowing until weaning (d 21±2.3). Litters were cross-fostered until 48-h after farrowing to equalize litter size. Sows were weighed at d 112 of gestation and at weaning. Litter size and weight were collected at 24-h post-farrow and weaning. Daily feed intake was recorded from 48-h post-farrow until weaning. Data were analyzed using the GLIMMIX procedure of SAS with sow as the experimental unit. There was no evidence of interaction between ME and SID Lys for any response criteria. There was no evidence for an ME effect on sow performance. There was a quadratic effect (P&amp;lt; 0.05) of SID Lys on sow average daily feed intake, with the greatest intake at 0.85% SID Lys. Increasing SID Lys levels increased sow BW change (linear, P&amp;lt; 0.05). Litters from sows fed 3.4 Mcal of ME/kg had greater (P&amp;lt; 0.05) daily gain compared to those from sows fed 3.2 Mcal of ME/kg. Increasing SID Lys levels increased (linear, P&amp;lt; 0.05) litter weight at weaning and piglet daily gain. Wean-to-estrus interval, percentage of sows bred after weaning, total born on the subsequent parity, litter size at weaning, and percent of piglet removals were not influenced by dietary treatments. In summary, increasing ME levels did not affect sow performance, but improved litter and piglet daily gain. Increasing SID Lys levels improved both litter and sow performance.

Standardized ileal digestible lysine and valine-to-lysine requirements for optimal performance of 4 to 9-week-old Piétrain cross piglets

Reduction of crude protein (CP) content in swine diets must be associated with an adequate quantitative and qualitative provision of amino acids (AA). In piglet diets, the fifth limiting AA is Val, where deficiency has been proven to reduce feed intake. In addition, depending on the overall level of CP and AA, diets high or low in standardized ileal digestible (SID) Lys will have different branched chain amino acid (BCAA) balances, which may in turn affect the feed intake response. Therefore, two Lys dose response trials (Exp. 1 and 2) were performed to study the influence of different AA concentrations on feed intake and overall performance. CP levels differed between the two experiments (201–210 g/kg in Exp. 1 and 180 g/kg in Exp. 2). Next, one Val dose response (Exp. 3) was carried out to establish the optimal SID Val:Lys ratio for 4 to 9-week-old Piétrain piglets. In Exp. 1, raising dietary SID Lys from 8.50 to 13.50 g/kg resulted in a significant linear and quadratic increase of average daily gain (ADG) and gain to feed (G:F) (P < 0.001 and P < 0.01 respectively), while average daily feed intake (ADFI) showed a linear increase with increasing SID Lys levels (P < 0.001), with a tendency to a quadratic effect (P = 0.08). In Exp. 2, ADG and G:F responded linearly and quadratically to SID Lys levels from 8.50 to 13.50 g/kg (P < 0.001), and ADFI showed a quadratic (P < 0.001) but not linear (P = 0.144) response to increased dietary SID Lys. For Exp. 1, the break points were above the tested SID range. For Exp. 2, quadratic polynomial (QP) and broken line quadratic (BLQ) model for ADG gave an optimal SID Lys of 12.05 and 11.39 g/kg, respectively, the QP ADFI reached an optimum of 11.33 g/kg of SID Lys. For G:F an optimal SID Lys level of 13.23, 11.72, and 13.28 g/kg SID Lys were estimated with a QP, broken line linear (BLL), and BLQ respectively. In Exp. 3, increasing the dietary SID Val:Lys level resulted in a linear and quadratic increase of ADG and ADFI (P < 0.001), but not G:F (P = 0.626 and P = 0.114). For ADG and ADFI it was possible to fit a QP and a BLQ model, with an optimal SID Val:Lys of 0.74 for the QP and 0.68 for the BLQ model, respectively, for the two response variables. In conclusion, SID Lys requirements of 4 to 9-week-old piglets are estimated to be equal or greater than 11.4 g/kg (1.14%), and SID Val:Lys requirements were found to be between 68 and 74% for optimal growth and feed intake.

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%.