Effects of increasing crystalline lysine and dietary fat on finishing pig growth performance

A total of 1,024 barrows (each initially 157 lb, PIC L337 x C22) were used in a 28-d study to evaluate the effects of increased crystalline amino acids (none versus 4.5 lb/ton of L-lysine HCl plus L-threonine to maintain the proper ratio relative to lysine) and added dietary fat (none, 3 or 6% choice white grease) on finishing pig growth performance. All experimental diets were formulated with a constant true ileal digestible lysine:ME ratio based on NRC, (1998) ingredient values for ME. A minimum true ileal digestible threonine:lysine ratio of 68% and a minimum true ileal digestible methionine + cystine:lysine ratio of 55% were used in diet formulation. There was no synthetic amino acid by added fat interactions. Increasing added fat increased (linear, P<0.01) ADG and improved F/G. Replacing soybean meal with crystalline amino acids had no affect on growth performance. This indicates that the increased amounts of L-lysine HCl and added L-threonine were used as efficiently as amino acids provided from soybean meal. Neither adding fat nor crystalline lysine affected feed cost/lb of gain using current ingredient prices. However, margin over feed cost (profit) increased as added fat increased because of the increased pig weight due to improved ADG. In summary, these results confirm the improved ADG and F/G when adding fat to finishing pig diets. Furthermore, 4.5 lb/ton of Llysine HCl and L-threonine can effectively replace soybean meal without negatively affecting growth performance of pigs from 157 to 217 lb

Effects of replacing soybean meal with high- protein dried distillers grains with solubles on growth performance, carcass characteristics, and carcass fat quality in finishing pigs

A total of 204 barrows and gilts (PIC, 337 × 1050, initially 129.6 lb) were used in a 73-d study to determine the effects of replacing soybean meal (SBM) with high-protein dried distillers grains with solubles (HPDDGS) on growth performance, carcass characteristics, and carcass fat quality in finishing pigs. Pens of pigs (3 barrows and 3 gilts per pen) were randomly allotted by initial BW to 1 of 4 treatments with 8 or 9 replications per treatment. All pigs were fed diets with 15% HPDDGS for 10 d prior to the start of the study. Treatments included: (1) corn-soybean meal diet with 0.15% crystalline lysine, (2) HPDDGS and crystalline amino acids replacing 50% of the SBM in diet 1, and two diets in which 100% of the SBM was replaced by either: (3) HPDDGS and a high amount of crystalline amino acids or (4) a high amount of HPDDGS and low levels of crystalline amino acids. Diets with low amounts of crystalline amino acids (Treatment 4) contained 10% more HPDDGS to replace SBM than diets with high amounts of crystalline amino acids (Treatment 3). Diets were fed in three 28-d phases (130 to 180 lb, 180 to 240 lb, and 240 to 280 lb) for Phases 1, 2, and 3, respectively. Diets 1 and 3 in all phases were blended (50:50) via the FeedPro system (Feedlogic Corp., Willmar, MN) to make diet 2. Overall, replacing 50% of the SBM with HPDDGS and crystalline amino acids had no effect on growth performance; however, replacing 100% SBM with HPDDGS and crystalline amino acids resulted in decreased (P 0.75) in F/G. In the two diets where 100% of the soybean meal was replaced with HPDDGS, the amount of added crystalline amino acids had no effect on growth performance

The optimal true ileal digestible threonine requirement for nursery pigs between 24 to 49 lb

A 22-d growth assay was conducted to determine the appropriate true ileal digestible threonine requirement to maximize growth performance of pigs between 24 and 49 lb. The 10 experimental treatments consisted of two basal diets (1.1% and 1.2% true ileal digestible lysine; 16.1% and 17.4% CP) with increasing levels of threonine (50, 55, 60, 65, 70% threonine:lysine). Pigs fed 1.2% true ileal digestible lysine had improved ADG and F/G compared to pigs fed 1.1% lysine, this suggest that the requirement was greater than 1.1% true ileal digestible lysine. There was a threonine × lysine interaction for feed efficiency. Pigs fed 1.1% true ileal digestible lysine had a greater response to increasing levels of threonine than pigs fed the diet containing 1.2% lysine. Increasing levels of threonine had no effect on ADG. Feed efficiency improved with increasing levels of true ileal digestible threonine:lysine and was maximized at 70% and 65% threonine:lysine for pigs fed 1.1% and 1.2% true ileal digestible lysine, respectively. However, the greatest improvements in feed efficiency were observed as the ratio increased to approximately 60%

Effects of increasing dietary lysine in transition diets on nursery pig growth performance

A total of 1,400 weanling pigs (initially 13.6 lb) was used in a 9 d growth assay (d 4 to 13 postweaning) to determine the effects of increasing lysine in the transition diet on nursery pig growth performance. All pigs were fed a common SEW diet until d 4 after weaning. Pigs were then switched to experimental diets with total dietary lysine levels of 1.40, 1.50, 1.60, 1.70 or 1.80%. All diets were formulated to contain 20% soybean meal, with increasing amounts of synthetic amino acids to achieve desired amino acid concentrations in the diets. From d 4 to 9 postweaning, increasing lysine increased ADG (linear, P<0.03) and improved feed efficiency (linear, P<0.001), but ADFI was not affected. Overall (d 4 to 13 postweaning), pigs fed diets containing increasing dietary lysine had improved ADG (linear, P<0.03) and feed efficiency (linear, P<0.001), with no differences in ADFI. Although responses to increasing dietary lysine were linear, there was little improvement either ADG or F/G above 1.7% lysine. There was no difference in average pig weight at the end of the trial, probably because of the short duration of the study. In conclusion, increasing dietary lysine up to 1.7% in transition diets (13 to 19 lb) for nursery pigs maximized growth performance

Effects of increasing dietary lysine in phase ii diets (15- to 25-lb) on nursery pig growth performance

A total of 1,260 weanling pigs (initially 18.6 lb) was used in a 19 d growth assay (d 10 to 29 after weaning) to determine the effects of increasing lysine in Phase II diets on nursery pig growth performance. All pigs were weaned and fed 1.2 lb per pig of a SEW diet, then switched to a transition diet until day 10 after weaning. Pigs were then weighed and switched to experimental diets containing true digestible lysine levels of 1.22, 1.32, 1.42, 1.52, and 1.62%, corresponding to approximately 1.36, 1.47, 1.56, 1.65, and 1.75% total lysine. All diets were formulated to contain 30% soybean meal, with increasing amounts of synthetic amino acids to achieve desired amino acid concentrations in the diets. From d 10 to 17 after weaning, increasing lysine increased ADG (quadratic, P<0.04) and improved feed efficiency (quadratic, P<0.01), with both appearing to be maximized at 1.52% true ileal digestible lysine. From d 17 to 24 and 24 to 29, ADFI and F/G improved (linear, P<0.05) with increasing true ileal digestible lysine. For the overall study, (d 10 to 29 after weaning), increasing true ileal digestible lysine increased ADG (quadratic, P<0.07) and improved feed efficiency (quadratic, P<0.001). In conclusion, 1.52% true ileal digestible lysine maximized both ADG and F/G early in the study, but the lysine requirement appeared to decrease to 1.42% from d 17 to 24. Results of two recent studies conducted at the University of Missouri with similar lysine levels fed to 15- to 25-lb pigs suggest a requirement estimate between 1.32 and 1.42% true ileal digestible lysine, slightly lower than the requirements observed in the present study

The optimal true-ileal-digestible lysine and threonine requirements for growing-finishing pigs from 80 to 130 and 170 to 230 pounds

A total of 4388 pigs (PIC 337 × C22; Exp. 1: 1070 gilts, initially 79 lb BW; Exp. 2: 3318 pigs, initially 170 lb BW) were used in 28-d growth assays to examine both the true-ileal-digestible (TID) lysine and threonine requirements, and then determine the appropriate TID threonine-to-lysine ratio in growing-finishing pigs from 80 to 130 lb and 170 to 230 lb. In Exp. 1, four TID lysine (0.71. 0.81, 0.91, and 1.01%) and five TID threonine (0.50, 0.56, 0.62, 0.68 and 0.74%) concentrations were evaluated. In Exp. 2, four TID lysine (0.56, 0.64, 0.72, and 0.80%), and five TID threonine (0.43, 0.48, 0.53, 0.58 and 0.63%) concentrations were evaluated. The diet with the highest concentration of lysine and second- highest concentration of threonine served as a positive control in both studies, and this diet was combined as one treatment to give a total of nine treatments in each study. Other amino acids were formulated to meet, or exceed, requirement estimates to ensure that lysine and threonine were the only limiting amino acids. In Exp. 1, increasing TID lysine tended to increase ADG (quadratic, P<0.06), with the greatest response occurring from 0.71 to 0.81%. Increasing TID lysine also quadratically increased ADFI (P0.69) or ADFI (P>0.29), but improved F/G (linear, P<0.05), with the maximum response occurring at 0.68% TID threonine. Values of 1.01% TID lysine and 0.68% TID threonine in Exp. 1 suggest an optimal TID threonine-to-lysine ratio of 67% for F/G. In Exp. 2, a treatment × gender interaction was observed for F/G (P<0.02). This was because gilts had a greater response to increasing TID lysine, whereas barrows had a greater response to increasing TID threonine. In Exp. 2, increasing TID lysine improved ADG (linear, P<0.05) in gilts and barrows (P<0.07), and improved F/G (linear, P<0.01) in gilts, as the TID lysine concentration increased to 0.72%. Increasing TID threonine improved ADG and F/G (linear, P<0.04) in barrows and increased ADG and ADFI (linear, P<0.06) in gilts as the threonine concentration increased to 0.48%. Values of 0.72% TID lysine and 0.48% TID threonine in Exp. 2 suggest an optimum TID threonine-to-lysine ratio of 67%. The practical TID threonine-to-lysine ratio suggested by this study for pigs from 80 to 130 lb and from 170 to 230 lb is 67%. Further research is needed to verify these results and evaluate the economics of feeding higher threonine concentrations

Effects of porcine circovirus type 2 vaccine and increasing standardized ileal digestible lysine:calorie ratio on growth performance and carcass composition of growing and finishing pigs

A series of 4 experiments was conducted to determine the effect of porcine circovirus type 2 (PCV2) vaccination on the lysine requirement of growing and finishing pigs. Experiments 1 and 2 evaluated the requirement for 85- to 140-lb gilts and barrows, respectively. Experiments 3 and 4 evaluated the requirement for 225- to 275-lb gilts and 215- to 260-lb barrows, respectively. Data from each trial were analyzed as 2 × 4 factorial designs with 2 PCV2 vaccination treatments (vaccinates and non-vaccinates) and 4 levels of increasing standardized ileal digestible (SID) lysine:ME ratio (2.24, 2.61, 2.99, and 3.36 g/Mcal in Exp. 1 and 2 and 1.49, 1.86, 2.23, and 2.61 g/Mcal in Exp. 3 and 4). No PCV2 vaccination × SID lysine:ME ratio interactions were observed (P > 0.14) in any of the 4 studies. In Exp. 1 and 2, PCV2 vaccinates had increased (P < 0.04) ADG, ADFI, final weight, and daily SID lysine intake and tended to have improved (P < 0.09) F/G compared with non-vaccinates. In Exp. 1, ADG and F/G improved (quadratic; P < 0.03) as the SID lysine:ME ratio increased, with increases through 2.99 g/Mcal. In Exp. 2, increasing the SID lysine:ME ratio improved (linear; P < 0.001) F/G and increased (linear; P < 0.001) daily SID lysine intake and SID lysine intake per pound of gain. Thus, 3.36 g SID lysine/Mcal ME appears to maximize efficiency for 85- to 140-lb barrows. In Exp. 3, PCV2 vaccinates had improved (P < 0.02) F/G and increased (P < 0.03) final weight, SID lysine intake per pound of gain, and backfat thickness compared with non-vaccinates. Both ADG and F/G improved (quadratic; P < 0.05) as the SID lysine:ME ratio increased, with ADG improving through 1.86 g/Mcal and F/G improving through 2.23 g/Mcal, indicating the requirement may be between those levels. In Exp. 4, both ADG and ADFI were decreased (P < 0.04) in vaccinates compared with non-vaccinates. In this study, ADG, F/G, daily SID lysine intake, and SID lysine intake per pound of gain increased (linear; P < 0.001) and F/G improved (linear; P < 0.001) through the highest level of 2.61 g lysine/Mcal, with the greatest magnitude of change when lysine was increased from 2.23 to 2.61 g/Mcal. Because of the lack of any interactions between dietary SID lysine level and PCV2 vaccination, it appears that PCV2 vaccination did not increase the lysine requirement for growing and finishing barrows and gilts. On the basis of these studies, which used corn-soybean meal-based diets with 3% added fat, the requirement was 1.04% SID lysine or 1.17% total lysine for 85- to 135-lb gilts, 1.17% SID lysine or 1.31% total lysine for 85- to 140-lb barrows, 0.78% SID lysine or 0.88% total lysine for 225- to 275-lb gilts, and 0.91% SID lysine or 1.02% total lysine for 215- to 260-lb barrows

The interactive effects of pST and salbutamol on the lysine requirement of finishing pigs

A metabolism study was conducted to evaluate the interactive effects of daily pST injections and the β-agonist salbutamol on the lysine requirement of finishing pigs based on nitrogen retention. Sixteen finishing pigs (137 lbs initially) were exposed to one of four biological treatments for 32 d. These treatments were: 1) non-treated control; 2) 4 mg/d pST; 3) 2.75 ppm of dietary salbutamol; 4) both salbutamol and pST. Pigs were kept on the same biological treatment and offered one of four diets for an 8 d period in a Latin square arrangement. Diets were formulated to contain .8, 1.2, 1.6, and 2.0% dietary lysine, the assumed first-limiting amino acid. Pigs were acclimated to each diet for a 4 d period, after which feces and urine were collected for 4 d to evaluate nitrogen retention. Results indicate that the β-agonist salbutamol increased the daily feed consumption, daily gain, and the efficiency of gain; whereas pST injection reduced feed consumption and increased efficiency of gain. No interaction occurred between pST and salbutamol for percent nitrogen retention; however, pigs injected with pST and fed salbutamol had a higher daily nitrogen retention because of an increased nitrogen intake and improved nitrogen utilization. Pigs treated with pST had leaner carcasses with a higher percent muscle than non-treated controls or pigs fed salbutamol. These data suggest that pigs injected with pST have a dietary lysine requirement between 1.2 and 1.6%, whereas those fed salbutamol have a requirement similar to that of non-treated pigs, which may be confounded with increased daily feed intake. Pigs treated with both pST and salbutamol appear to have a lysine requirement slightly lower than that of pigs injected with pST alone, which appears to be due to increased feed intake

Effects of porcine circovirus type 2 vaccination on nursery and finishing pig performance under a PRRS challenge

A total of 2,571 barrows and gilts (PIC 337 × 1050) were used to determine the effects of porcine circovirus type 2 vaccine (PCV2) on nursery and finishing pigs that were challenged with porcine respiratory and reproductive syndrome (PRRS). Treatments were arranged in a 2 × 2 factorial design with main effects of gender (barrow or gilt) and vaccine (PCV2 vaccinates or non-vaccinates). Vaccinated pens received 2 doses of commercial PCV2 vaccine (Circumvent PCV, Intervet Inc., Millsboro, DE) according to label directions on d 1 and 22 in the nursery. All pigs were also inoculated on d 30 with serum containing PRRS virus as part of this production system’s protocol. Barns were double stocked from d 0 to 51. On d 51, gilts were moved to an adjacent facility and barrows were split into 2 pens. In the period after the initial PCV2 vaccination (d 0 to 15), no difference in ADG, ADFI, or F/G was observed (P > 0.13) between genders or between vaccinates and non-vaccinates. However, in the period after the second PCV2 vaccination (d 15 to 29), vaccinated pigs had decreased (P 0.61) for ADG, ADFI, or final weight among gender or PCV2 vaccinates and non-vaccinates. However, F/G was improved (P < 0.001) with PCV2 vaccination. Pig weights on d 71 and 99 were increased (P < 0.001) in vaccinates compared with non-vaccinates, and barrows had increased (P < 0.001) BW compared with gilts on d 99. At the conclusion of the study (d 132 for barrows and d 142 for gilts), the percentage of pigs remaining on test was decreased (P < 0.001) in non-vaccinated pens compared with vaccinated pens (70.2% vs. 94.7%, respectively). This study suggests that despite the decrease in performance related to the second vaccination of PCV2, the second vaccination improved final performance and decreased the number of removals due to the PRRS health challenge