SID Lys Research Articles

The Implications of Nutritional Strategies that Modify Dietary Energy and Lysine for Growth Performance in Two Different Swine Production Systems.

Simple SummaryReducing dietary energy is a common practice for dealing with the price volatility of high energy sources, such as fats and oils, which are the costliest constraints in swine feed formulation. Theoretically, pigs can overcome a reduced energy density by increasing feed intake; however, as other factors like fibrous ingredients limit feed intake physically rather than metabolically, reducing dietary energy could also entail a lower energy intake. The expected effect on feed intake also influences lysine intake, and therefore, when NE trials are conducted, it is necessary to ensure that lysine is not a limiting factor for growth. In the present work, the effects of two dietary energy and lysine levels were tested in a factorial arrangement. The same approach of different levels was analyzed in two different swine production systems targeting different carcass traits. The experiment showed that in one system, reducing energy density did not impair growth; however, in the other system, it limited growth slightly by limiting fat deposition. Although reducing energy density increased feed intake, pigs could not reach a similar energy intake, and consequently were more efficient using energy for growth.This work aimed to determine the impacts of lowering dietary net energy (NE) density in two swine production systems that produce pigs with different carcass traits. To ensure that dietary lysine was not limiting growth, two studies were conducted in a 2 × 2 factorial arrangement with NE and standardized ileal digestible lysine (SID Lys) as experimental factors. A total of 1248 pigs were used in each study, Pietrain (Exp. 1, males non-castrated) or Duroc (Exp. 2, males castrated) sired. Reducing NE resulted in a greater feed intake; however, this was not sufficient to reach the same NE intake. While in Exp. 1 a 3.2% lower NE intake did not impair average daily gain (ADG; p = 0.220), in Exp. 2 a 4.7% lower NE intake reduced ADG by 1.4% (p = 0.027). Furthermore, this effect on ADG entailed a reduced ham fat thickness (p = 0.004) of the first marketed pigs. Increasing SID Lys only had a positive effect in Exp. 1, but no significant interaction between NE and SID Lys was reported (p ≥ 0.100). Therefore, dietary NE can be reduced without impairing growth performance when pigs can increase feed intake sufficiently, and thus, limit energy deficiencies.

Evaluation of a decision support system for precision feeding of gestating sows.

Precision feeding (PF) with the daily mixing of 2 diets with different lysine content (high (H) or low (L)) was previously reported for growing pigs to reduce protein intake and N excretion compared with a conventional feeding (CF) based on a single diet (C). Using a simulation approach based on farm data, the objective of the present paper was to describe and evaluate a decision support system for the PF of gestating sows allowing the daily distribution of a tailored ration to each sow. Two datasets, 1 of 2,511 gestations (farm A) and 1 of 2,528 gestations (farm B), reporting sows’ characteristics at insemination and objectives at farrowing were used as inputs for a Python model. This model, mainly based on InraPorc, calculates the nutrient requirements of each sow over gestation and simulates the impact of PF in comparison to CF. Simulated diets L, H, and C contained 3.0, 6.5, and 4.8 g/kg of standardized ileal digestible lysine (SID Lys) and 2.0, 3.3, and 2.5 g/kg of standardized total tract digestible phosphorus (STTD-P), respectively. The influence of farm, parity, gestation week, and their interactions, on calculated SID Lys and STTD-P requirements was analyzed applying a mixed model. The calculated SID Lys and STTD-P requirements increased markedly in the last third of gestation (P < 0.01) and were higher for primiparous than for multiparous sows, unless after week 14 for STTD-P requirement. The calculated SID AA and mineral requirements were lower for farm B than farm A (respectively, 2.94 vs. 3.08 g/kg for SID Lys and 1.30 vs. 1.35 g/kg for STTD-P, P < 0.01). On average, feed L represented 86% and 92% of the feed projected to be delivered by the PF strategy in farms A and B, respectively. Compared to CF, average calculated dietary SID Lys content was lowered by 27% and 32% with PF, for farms A and B, respectively, while average calculated dietary phosphorus content was lowered by 13% and 16%. The simulated proportions of sows in excess and deficient in SID Lys were reduced with PF. Compared to CF, the PF strategy allowed for a 3.6% reduction in simulated feed cost per sow during gestation, and reduced nitrogen and phosphorus intake (by 11.0% and 13.8%, respectively) and excretion (by 16.7% and 15.4%, respectively). To conclude, these simulations indicate that PF of gestating sow appears to be relevant to meet the amino acid requirement while reducing feed cost, and supplies and excretion of nitrogen and phosphorus.

Interrelationships between sex and dietary lysine on growth performance and carcass composition of finishing boars and gilts.

The main goals of this study were to determine whether boars and gilts respond differently to the standardized ileal digestible lysine to net energy ratio (SID Lys:NE) and model the response to optimize growth performance. A total of 780 finishing pigs, 390 boars and 390 gilts [Pietrain NN × (Landrace × Large White)], with an initial individual body weight of 70.4 ± 9.2 for boars and 68.7 ± 8.0 kg for gilts, were used in a 41-d dose–response experiment. Pens (13 pigs per pen) were randomly allocated to a dietary treatment (2.64, 3.05, 3.46, 3.86, 4.27 g SID Lys/Mcal NE) by block and sex, with six replicates per treatment and sex. Two isoenergetic diets (2,460 kcal NE/kg), representing the extreme SID Lys:NE, were formulated and then mixed. Pigs were individually weighed at days 0, 22, and 41, when the experiment finished. The differential effect of SID Lys:NE on growth performance and carcass composition between sexes was analyzed with orthogonal polynomial contrasts to compare the linear and quadratic trends in each sex. In addition, broken-line linear (BLL) models to optimize average daily gain (ADG), including average daily feed intake (ADFI) as a covariate, were fitted when possible. As expected, boars had a greater ADG and feed efficiency (G:F; P < 0.001) than gilts, but there was no evidence of differences in ADFI (P = 0.470). Increasing SID Lys:NE had a greater linear impact on boars ADG (P = 0.087), G:F (P = 0.003), and carcass leanness (P = 0.032). In contrast, gilts showed a greater linear increase in SID Lys intake per kg gain (P < 0.001) and feed cost per kg gain (P = 0.005). The best fitting BLL models showed that boars maximized ADG at 3.63 g SID Lys/Mcal NE [95% confidence interval (CI): (3.32 to 3.94)], although another model with a similar fit, compared with the Bayesian information criterion, reported the optimum at 4.01 g SID Lys/Mcal NE [95% CI: (3.60, 4.42)]. The optimum to maximize ADG for gilts was estimated at 3.10 g SID Lys/Mcal NE [95% CI: (2.74, 3.47)]. Thus, the present study confirmed that boars and gilts have a different linear response to SID Lys:NE, explained by the greater protein deposition potential of boars. Likewise, BLL models indicated that boars require a higher SID Lys:NE to maximize ADG from 70 to 89 kg. These results suggest that split feeding of finishing boars and gilts could be beneficial in terms of both performance and cost return.

Increasing Dietary Lysine Impacts Differently Growth Performance of Growing Pigs Sorted by Body Weight.

Simple SummaryThe increasing demand on animal products expected for the next decades requires animal production systems to become more efficient in resource use. Most commercial operations feed all pigs the same feed at a determined time depending on the average BW of the batch, but without considering the variability of the population. However, low body weight (BW) pigs have been related to extra costs as reduced barn utilization, losses due to the poor carcass grading and inefficiency of phase feeding strategies. Some studies have previously hypothesized the need to do different phase feeding strategies to pigs sorted by initial BW. This work aimed to compare the effect of increasing the standardized ileal digestible lysine to net energy ratio (SID Lys:NE) over the performance of growing pigs sorted by initial BW in 3 categories (small, medium, and large). The results showed that small pigs could use more efficiently high SID Lys:NE diets compared to the large pigs during the growing phase (28–63 kg). The conclusions imply positive effects of feeding higher dietary lysine to small pigs to compensate for their reduced feed intake capacity. This strategy might improve growth rate and feed efficiency, without increasing feed costs per kg gain.An experiment was conducted analyzing whether growing pigs classified in different initial body weight categories (BWCAT) have a different response to increasing standardized ileal digestible lysine to net energy ratio (SID Lys:NE), to assess whether light pigs might benefit from being differentially fed. A total of 1170 pigs in pens of 13 were individually weighed, classified in 3 BWCAT (Lp: 32.1 ± 2.8 kg, Mp: 27.5 ± 2.3 kg, and Sp: 23.4 ± 2.9 kg), and afterwards pens were randomly allocated to 5 dietary SID Lys:NE treatments (3.25 to 4.88 g/Mcal) fed over 47 days. Results reported a greater linear improvement of growth and feed efficiency of Sp compared to Lp when increasing SID Lys:NE. Modelling the response to SID Lys:NE using quadratic polynomial models showed that the levels to reach 98% of maximum growth from day 0–47 were 3.67, 3.88, 4.06 g SID Lys/Mcal NE for Lp, Mp, and Sp, respectively. However, due to the overlapping SID Lys:NE confidence intervals at maximum performance, it was not possible to determine if requirements were different between BWCAT. Summarizing, the results suggested that feeding small pigs greater SID Lys:NE than large pigs can improve their performance and increase the efficiency of the overall production system.

Increasing the ratio of SID lysine to metabolizable energy improves pig performance during a viral challenge.

Porcine reproductive and respiratory syndrome virus (PRRSV) compromises pig performance. However, increasing standardized ileal digestible Lys per Mcal metabolizable energy (SID Lys:ME) above requirement has been shown to mitigate reduced performance seen during a porcine reproductive and respiratory syndrome (PRRS) virus challenge. The objective of this study was to evaluate the effects of increasing the dietary SID Lys:ME from 100% National Research Council (NRC) requirement to 120% of the requirement in vaccinated (vac+; modified live vaccine Ingelvac PRRS) and non-vaccinated (vac−; no PRRS vaccine) grower pigs subjected to a PRRSV challenge. In addition, the dietary formulation approach to achieve the 120% ratio by increasing Lys relative to energy (HL) or diluting energy in relation to Lys (LE) was evaluated. This allowed us to test the hypothesis that pigs undergoing a health challenge would have the ability to eat to their energy needs. Within vaccine status, 195 mixed-sex pigs, vac+ (35.2 ± 0.60 kg body weight [BW]) and vac− (35.2 ± 0.65 kg BW) were randomly allotted to one of three dietary treatments (2.67, 3.23, or 3.22 g SID Lys:ME) for a 42-d PRRS virus challenge study representing 100%, 120%, and 120% of NRC requirement, respectively. Pigs were randomly allotted across two barns, each containing 24 pens with 7 to 10 pigs per pen (8 pens per diet per vaccine status). On day post-inoculation 0, both barns were inoculated with PRRSV and started on experimental diets. Within vaccine status, weekly and overall challenge period pig performance were assessed. In both vac+ (P < 0.05) and vac− (P < 0.05) pigs, the HL and LE diets increased end BW and overall average daily gain (ADG) ADG compared with pigs fed the control diet (P < 0.05). Overall, average daily feed intake (ADFI) during the challenge period was greater (P < 0.05) for pigs fed the LE diet compared with pigs fed control and HL treatments, regardless of vaccine status (20% and 17% higher ADFI than the control in vac+ and vac− pigs, respectively). The HL vac+ pigs had the greatest gain to feed (G:F) compared with the control and LE pigs (0.438 vs. 0.394 and 0.391 kg/kg, respectively; P < 0.01). Feed efficiency was not impacted (P > 0.10) by treatment in the vac− pigs. In summary, PRRSV-challenged grower pigs consumed feed to meet their energy needs as indicated by the increase in ADFI when energy was diluted in the (LE) diet, compared with control pigs. In both PRRS vac+ and vac− pigs subsequently challenged with PRRSV, regardless of formulation approach, fed 120% SID Lys:ME diets resulted in enhanced overall growth performance.

Effects of different standardized ileal digestible lysine: net energy proportion in growing and finishing pigs.

This experiment was performed to evaluate the optimal proportion of dietary standardized ileal digestible lysine (SID Lys) to net energy (NE) proportion in growing to finishing pigs. A total of seventy-two pigs were used at phase 1 (initial body weight 37.23 ± 0.23 kilogram, for 42 d) and at phase 2 (initial body weight 54.16 ± 0.20 kilogram, for 77 d). They were arbitrarily assigned to three treatments groups consisting of four duplicates per treatment (six pigs in duplicates, respectively). Diet treatments were as follows: CON = basal diets (phase 1, crude protein (CP): 19.1%; SID Lys: 0.94%; SID Lys: NE proportion: 0.91 g/MJ / phase 2, CP: 17.0%; SID Lys: 0.84%; SID Lys: NE proportion: 0.79 g/MJ), TRT1 (phase 1, CP: 18.0%; SID Lys: 0.92%; SID Lys: NE proportion: 0.89 g/MJ / phase 2, CP: 15.8%; SID Lys: 0.8%; SID Lys: NE proportion: 0.75 g/MJ), TRT2 (phase 1, CP: 17.3%; SID Lys: 0.82%; SID Lys: NE proportion: 0.79 g/MJ / phase 2, CP: 14.8%; SID Lys: 0.7%; SID Lys: NE proportion: 0.65 g/MJ). In phase 1 and 2, growth performance did not meaningfully be affected when SID Lys: NE proportion decreased with reducing CP content. In phase 2, the nitrogen digestibility of CON group in 11 week was higher (p < 0.05) than other treatments. Also, marbling and firmness scores of TRT2 group diets increased (p < 0.05) compared with those of CON group, but dissimilarities of other meat qualities did not be detected among treatments. In conclusion, introduction of NE system can reduce negative problems introduced when dietary CP decreased. Also, 0.79 and 0.65 g/MJ of SID Lys: NE proportion is the optimal Lys: NE proportion to achieve improved pork quality without impairing the growth performance in growing-finishing pigs, respectively.

Effect of Increasing Dietary Aminoacid Concentration in Late Gestation on Body Condition and Reproductive Performance of Hyperprolific Sows.

Simple SummaryNutrition during gestation is relevant for the success of reproductive sows and the late pregnancy is an especially critical period. Currently, the usual feeding management includes only one diet supplied at different levels through pregnancy and it could not be enough. Additionally, modern sows are producing large litters; their requirements are probably higher than those of commercial sows and they have to be met. With the current study, it can be concluded that a high level of amino acids in the diet provided approximately during the last month of gestation (around 10 g of standardized ileal digestibility lysine/kg of feed, with the remaining essential AA following the ideal protein concept) could be a strategy to improve the sow body condition and the reproductive performances.A total of 62 highly prolific Danbred sows was used to evaluate the implications of increasing dietary amino acid (AA) concentration during late gestation (from day 77 to 107 of pregnancy) on body condition and reproductive performances. Sows were assigned to one of the two treatments (n = 31, with similar number of sows in the second-, third- and fourth-cycle); control diet (containing 6 g of standardized ileal digestible lysine -SID Lys-)/kg) and high AA level (containing 10 g SID Lys/kg and following the ideal protein concept for the remaining essential AA). On day 108 of pregnancy, animals were moved to the farrowing-lactating facilities where they spent until weaning receiving a common standard lactation diet. After farrowing, litters were standardized to 13 piglets each. At 107 d of gestation, backfat depth was thicker in sows fed high AA concentration than in those fed control diet (p < 0.0001) but these significant differences disappeared at weaning (p > 0.05). Additionally, at farrowing, the litter size (p = 0.043) and weight (p = 0.017) were higher in sows fed high AA level. It can be concluded that the increase in the AA content in the feed during the last month of gestation could improve the body condition of the sows and their performance results.

Effects of different amounts and type of diet during weaning-to-estrus interval on reproductive performance of primiparous and multiparous sows

During weaning-to-estrus interval (WEI), the sows are usually fed with high feed level to improve the reproductive performance. However, the WEI has been reduced over the years which may reduce the impact of feed level on performance in the modern genetic lines. The aim of this study was to evaluate the effect of two feeding levels (moderate feeding level (MFL): 2.7 kg/day and high feeding level (HFL): 4.3 kg/day) and two diet types (gestation: 13.67 MJ/kg of metabolizable energy (ME) and 0.62% of standard ileal digestible lysine (SID Lys) and lactation: 14.34 MJ ME/kg and 1.20% of SID Lys) offered during the WEI on reproductive performance. In total, 19.0% of sows were excluded from the analysis due to feed intake below 75% (9.6% and 28.5% in MFL and HFL groups, respectively), remaining 254 primiparous and 806 multiparous sows. Follicular size and change in BW were measured in subsamples of 180 and 227 females, respectively. Data were analyzed considering the sow as the experimental unit. Feeding level, diet type, parity and their interactions were included as fixed effects, whereas the day of weaning was considered as a random effect. The feed intake of MFL and HFL groups averaged 2.5 ± 0.02 and 3.8 ± 0.02 kg/day, respectively. There was an interaction between feeding level and parity for daily feed intake. Within HFL, multiparous sows consumed 181 g/day more than primiparous sows (P < 0.01), but no difference was observed within MFL (P > 0.05). Both primiparous and multiparous sows lost proportionally less weight when fed HFL than MFL gestation diet during WEI. The percentage of weight loss was lower in HFL than in the MFL group in multiparous sows fed the lactation diet. The WEI was not affected by feeding level, diet type or its interaction (P > 0.05), but it was longer in primiparous than in multiparous sows (P = 0.001). There was no effect of feeding level, diet type, parity or their interactions on anestrus and farrowing rates. Multiparous sows showed greater follicular size, and greater numbers of total born and born alive piglets in the subsequent cycle than primiparous sows (P < 0.05). In conclusion, feeding weaned primiparous and multiparous sows with 4.3 kg/day of a gestation (58.78 MJ ME and 26.66 g SID Lys) or a lactation diet (61.66 MJ ME and 51.60 g SID Lys) does not improve follicular size and reproductive performance in the subsequent cycle.

Effect of Fiber Source and Crude Protein Level on Nursery Pig Performance

A total of 360 pigs (200 × 400; DNA, Columbus, NE; initially = 11.0 lb) were used in a 45-d growth trial to evaluate the effects of fiber source and crude protein level on growth performance and fecal dry matter of nursery pigs. Upon arrival to the nursery research facility, pigs were randomly assigned to pens with 5 pigs per pen and 9 replicate pens per treatment. Dietary treatments were arranged in a 2 × 4 completely random­ized factorial with main effects of crude protein (21 or 18% CP) and fiber source (none, coarse wheat bran, oat hulls, or cellulose; Arbocel, J. Rettenmaier USA, Schoolcraft, MI). Treatment diets were formulated in two dietary phases from d 0 to 10 and 10 to 24, with a common post-treatment diet fed from d 24 to 45. The 21% CP diets contained 1.40% standardized ileal digestible lysine (SID) in phase 1 and 1.35% SID Lys in phase 2. Treatment diets were formulated to a maximum SID Lys:digestible CP level of 6.35%, thus SID Lys decreased in the 18% CP (1.25% SID Lys) diets to main­tain the ratio. Diets containing a fiber source were formulated to the level of insoluble fiber provided by 4% coarse wheat bran, resulting in the addition of 1.85% oat hulls and 1.55% cellulose to the respective diets. No fiber source × CP level interactions (P > 0.05) were observed throughout the study. During the experimental period, decreasing dietary CP (and subsequently SID Lys) decreased (P = 0.05) ADG, and d 24 body weight (BW) and worsened feed efficiency (F/G). Average daily gain and d 45 BW decreased (P < 0.05) for pigs fed 18% CP diets compared to pigs fed 21% CP diets overall from 0 to 45. Fecal dry matter on d 17 was increased (P < 0.001) for pigs fed 18% CP diets compared to pigs fed 21% CP diets. No main effects of fiber source were observed for growth performance throughout the study. However, fecal dry matter percentage increased (P < 0.05) for pigs fed added cellulose compared to pigs fed no fiber or coarse wheat bran on d 10 and 24 of the trial. Similarly, pigs fed cellulose had increased (P = 0.028) fecal dry matter compared to pigs fed no fiber, with pigs fed coarse wheat bran and oat hulls intermediate. In conclusion, reducing dietary crude protein resulted in decreased growth performance while minimal improvements in fecal dry matter were observed during the experimental period. The source or inclusion of insoluble fiber in nursery diets had no impact on performance. The inclusion of cellu­lose improved fecal dry matter compared to feeding no dietary fiber or coarse wheat bran.

PSVII-25 Intra-Farm Variability: Growing pigs have different SID Lys:NE requirements depending on their BW category

Abstract The objective of this experiment was to determine if pigs with different initial body weight within the same farm batch have different SID Lys:NE requirements. In the trial 1,170 growing crossbred pigs were distributed in 90 pens (13 pigs/pen) and split in three initial BW categories: Large, Medium and Small (32.1 ± 2.8, 27.5 ± 2.3 and 23.4 ± 2.9 kg, respectively). Each pen was randomly assigned by BW to one of the SID Lys:NE levels (3.25, 3.66, 4.07, 4.47 and 4.88 g SID Lys/Mcal NE), with 6 replicates per dietary treatment. All diets were isoenergetic (2460 kcal NE/kg), and CP ranged from 14.50 to 17.50 %. The dietary treatments were fed for 26 days. Statistical analysis to determine the effect of SID Lys:NE was performed using the GLM procedure of SAS with linear and quadratic polynomial contrasts. In addition, broken-line linear models were fit with the NLIN procedure of SAS to determine the break-point to maximize ADG or minimize FCR for all categories together or independently. The ADG break-point for all pigs was determined at 3.89 g SID Lys/Mcal NE. However, when analyzed by categories, the break-point was 3.86, 4.07 and 4.76 g SID Lys/Mcal NE for large, medium and small pigs respectively. The general break-point for FCR was determined at 4.25 g SID Lys/Mcal NE. By BW categories the different break points determined were: 4.27, 4.15 and 4.59 g SID Lys/Mcal NE for large, medium and small pigs, respectively. In conclusion, the estimated requirement to maximize ADG and optimize FCR via broken-line models is higher for small pigs than large or medium. Therefore, pigs within the same farm batch should be differentially fed in relation to the SID Lys:NE ratio.

83 The impact of xylanase on arabinoxylan hydrolysis when included in corn or wheat based diets fed to swine

Abstract Carbohydrases added to swine diets hydrolyze non-starch polysaccharides (NSP) to smaller oligosaccharides, decreasing their degree of polymerization (DP). Wheat contains more NSP in the form of arabinoxylans (AX), however corn AX have higher arabinose:xylose. This experiment determined the potential for a differential response to the carbohydrase, xylanase, when added to corn or wheat based diets for swine. Twelve ileal cannulated barrows (BW 37±2.1kg) were used in a modified crossover design with a 2x2 factorial arrangement of treatments in two periods (n = 6). Grain (81.5% corn or 90.5% wheat) and xylanase (±0.01%, 16,000 XU/kg feed) were main effects. The crossover occurred only between xylanase; pigs remained on the same grain throughout and pig was randomized within sequence. Isoenergetic/isonitrogenous (3,500 Kcal ME/kg, 0.87% SID Lys) diets were fed at 3x maintenance for 18d; fecal and digesta samples were collected on d15-16 and d17-18, respectively. Ileal energy digestibility tended to improve with xylanase (71.3–73.8%; P &amp;lt; 0.10). Fecal energy digestibility was improved by xylanase in wheat, but not corn, based diets (grain*xylanase, P &amp;lt; 0.05). Ileal butyric acid was highest when pigs received the wheat diet without xylanase (grain*xylanase, P &amp;lt; 0.05). Xylanase had no effect on fecal short chain fatty acids (P &amp;gt; 0.10). Pigs fed wheat diets had increased percent fecal propionic and lower butyric and valeric acid than those fed corn diets (P &amp;lt; 0.05). Ileal arabinose:xylose ratio was reduced with xylanase in corn, but not wheat diets, while the opposite was observed in fecal samples (grain*xylanase, P &amp;lt; 0.05). Ileal samples from pigs receiving corn without xylanase had the highest AX-DP (grain*xylanase, P &amp;lt; 0.05). Fecal AX-DP was reduced with xylanase inclusion (P &amp;lt; 0.05) and was lower in wheat, than corn based diets (P &amp;lt; 0.05). Xylanase decreased AX-DP throughout the gastrointestinal tract and tended to improved ileal energy digestibility in corn and wheat based diets.

PSVII-27 Effects of dietary near ideal amino acid profile on amino acid utilization efficiency for milk production in sows under thermoneutral or heat stress conditions

Abstract The objective was to estimate essential AA (EAA) utilization efficiency for milk production in sows (n = 24) fed control (19.6% CP) or reduced CP (RCP; 14.2% CP) diets under thermoneutral (TN; 21±1.5°C) or cycling heat stress (HS; 32±1.5°C daytime and 24±1.5°C nighttime) conditions. We hypothesized that RCP fed lactating sows with supplemental AA have increased EAA efficiency for milk production under TN and HS conditions. Diets contained 0.90% SID Lys and 2,580 kcal/kg. Sow BW and backfat were recorded on d 1 and 21 to estimate body protein mobilization (BPM). Piglet BW was recorded on d 1 and 21 to estimate milk yield. Amino acid efficiencies were calculated based on milk AA output relative to SID AA intake corrected for AA contribution from BPM. During HS, N, Arg, His, Ile, Leu, Lys, Met, Phe, Thr, Trp, and Val efficiency for milk production did not differ between sows fed control (42, 26, 44, 36, 39, 49, 52, 32, 50, 43 and 44%, respectively) and RCP (56, 39, 51, 49, 56, 47, 42, 39, 50, 59 and 41%, respectively) diets. Compared to control sows, RCP sows had greater (P &amp;lt; 0.05) efficiency of Arg (30% vs. 61%) under TN condition. Efficiencies of His, Ile, Leu, Phe, and Trp tended to be greater (P = 0.07, 0.06, 0.06, 0.07 and 0.06, respectively) in RCP compared to control sows (50, 41, 44, 36, and 50% vs. 74, 67, 75, 54 and 78%, respectively). Efficiencies of Lys, Met, Thr, Trp and Val did not differ between control and RCP sows (56, 59, 57, and 50% vs. 67, 59, 69 and 57%, respectively). In summary, an RCP diet improved efficiency of N, Arg, His, Ile, Leu, Phe, and Trp for milk production in lactating sows under TN but not HS conditions.

PSXIII-6 Fat deposition in castrated pigs for production of dry-cured ham: Evaluation of nutritional and genetic strategies

Abstract Fat deposition is an important trait for the dry-cured ham industry. A minimum ham fat thickness (HFT) is required for adequate processing. The objective of this study was to evaluate two different strategies to meet this minimum requirement, a nutritional and a genetic one. The study involved productive performance of a total of 147,883 animals (barrows and gilts) from 164 farms. The experimental unit for carcass traits harvested was a truck with 200 pigs each. The nutritional strategy consisted in reducing the SID Lys:NE during one month before slaughter in combination with a feed additive to improve meat quality (2500 kcal NE and 8 g SID Lys/kg vs. 2550 kcal NE and 6.5 g SID Lys/kg). Both feeding programs were offered to crossbreds from a lean Duroc sire line with two different synthetic dam lines. The genetic strategy consisted of comparing two crossbred derived from two Duroc sire line (lean vs fat) all fed the same standard finisher diet (2500 kcal NE and 8 g SID Lys/kg). Experimental feeding program impaired FCR by 0.035 kg/kg (P &amp;lt; 0.05), and increased HFT by 0.28 mm (P &amp;lt; 0.01). The fat Duroc sire line impaired FCR by 0.162 kg/kg (P &amp;lt; 0.05) and increased HFT by 0.77 mm (P &amp;lt; 0.001) compared to the lean one. In addition, one of the dam lines showed a greater HFT (P &amp;lt; 0.001) with no effect on FCR. In conclusion, HFT can be increased through nutritional and genetic strategies assuming a negative effect on FCR. The effects were greater by using a genetic strategy (fatter Duroc sire line) than by the nutritional one (decreased SID Lys:NE ratio in a lean Duroc sire line).

Exploration of individual variability to better predict the nutrient requirements of gestating sows1.

Sows often receive the same feed during gestation even though their nutrient requirements vary during gestation and among sows. The objective of this study was to report the variability in nutrient requirement among sows and during gestation, in order to develop a precision feeding approach. A data set of 2,511 gestations reporting sow characteristics at insemination and their farrowing performance was used as an input for a Python model, adapted from InraPorc, predicting nutrient requirement during gestation. Total metabolizable energy (ME) requirement increased with increasing litter size, gestation weeks, and parity (30.6, 33.6, and 35.5 MJ/d for parity 1, 2, and 3 and beyond, respectively, P < 0.01). Standardized ileal digestible lysine (SID Lys) requirement per kg of diet increased from weeks 1 to 6 of gestation, remained stable from weeks 7 to 10, and increased again from week 11 until the end of gestation (P < 0.01). Average Lys requirement increased with increasing litter size (SID Lys: 3.00, 3.27, 3.50 g/kg for small, medium and large litters, P < 0.01) and decreased when parity increased (SID Lys: 3.61, 3.17, 2.84 g/kg for parity 1, 2, and 3++, P < 0.01). Standardized total tract digestible phosphorus (STTD-P) and total calcium (Total-Ca) requirements markedly increased after week 9, with litter size, and decreased when parity increased (STTD-P: 1.36 vs. 1.31 g/kg for parity 1 and parity 3 and beyond; Total-Ca: 4.28 vs. 4.10 g/kg for parity 1 and parity 3 and beyond, P < 0.01). Based on empirical cumulative distribution functions, a 4-diets strategy, varying in SID Lys and STTD-P content according to parity and gestation period (P1 from weeks 0 to 11, P2 from weeks 12 to 17), may be put forward to meet the requirements of 90% of the sows (2 diets for multiparous sows: P1: 2.8 g SID Lys/kg and 1.1 g STTD-P/kg; P2: 4.5 g SID Lys/kg and 2.3 g STTD-P/kg; and 2 diets for primiparous sows: P1: 3.4 g SID Lys/kg and 1.1g STTD-P/kg; P2: 5.0 g SID Lys/kg, 2.2 g STTD-P/kg). Better considering the high variability of sow requirement should thus make it possible to optimize their performance whilst reducing feeding cost and excretion. Feeding sows closer to their requirement may initially be achieved by grouping and feeding sows according to gestation week and parity, and ultimately by feeding sows individually using a smart feeder allowing the mixing of different feeds differing in their nutrient content.

361 Increasing duration of feeding high dietary lysine and energy before farrowing on colostrum quality and yield in mixed parity sows

Abstract A total of 472 mixed parity sows were used from d 106 of gestation until weaning to determine the effects of Lys and energy intake in the last 7 d before farrowing on colostrum production, composition, and immunoglobulin G concentrations. On d 106 of gestation, sows were weighed, blocked by parity and weight, and allotted to dietary treatments. Treatments were based on corn-soybean meal diets fed to provide 1) 12.5 g SID Lys and 6.5 Mcal/d ME from d 107 to 112 of gestation, then 28 g SID Lys and 9.4 Mcal/d ME from until farrowing; 2) 12.5 g SID Lys and 6.5 Mcal/d ME from d 107 to 112 of gestation, then 40 g SID Lys and 13.3 Mcal/d ME from until farrowing; 3) 40 g SID Lys and 13.3 Mcal/d ME from d 107 of gestation until farrowing. After birth of the first piglet, a 50 mL colostrum sample was collected. Colostrum samples were analyzed for fat, protein, total solids, lactose, and IgG concentrations. Individual piglets were weighed at birth and 24 h to determine colostrum intake and yield. Data was analyzed for treatment within parity and treatment main effects. There was a treatment within parity difference observed where sows on treatment 3 had decreased (P &lt; 0.05) fat and total solids concentrations compared to treatment 1 sows, with no evidence for difference within gilts. IgG concentrations tended to increase (P = 0.081) in females fed treatment 2 compared to treatment 1, regardless of parity. Total protein and lactose concentrations as well as colostrum intake and yield were similar across treatments, regardless of parity. In conclusion, feeding high Lys and energy for 7 d before farrowing decreased fat and solid concentrations in colostrum in sows, but did not impact other colostrum nutrients or colostrum production.

183 Effects of increasing duration of feeding high dietary lysine and energy prior to farrowing on sow and litter performance under commercial conditions

Abstract A total of 472 mixed parity sows were used in a study to evaluate the effects of supplying increased Lys and energy for the last 2 or 7 d before farrowing on sow and litter performance. On d 106 of gestation, sows were blocked by parity and weight and allotted to one of three corn-soybean meal-based dietary treatments, which included: 1) 12.5 g SID Lys and 6.5 Mcal/d ME from d 107 to 112 of gestation, then 28 g SID Lys and 9.4 Mcal/d ME until farrowing; 2) 12.5 g SID Lys and 6.5 Mcal/d ME from d 107 to 112, then 40 g SID Lys and 13.3 Mcal/d ME until farrowing; 3) 40 g SID Lys and 13.3 Mcal/d ME from d 107 until farrowing. Data were analyzed for treatment within parity effects using the GLIMMIX procedure of SAS. Sow weight gain from d 106 to 113 increased (P &lt; 0.05) as the length of feeding increased SID Lys and energy increased. Sow backfat gain from d 106 to 113 of gestation increased (P &lt; 0.05) in females fed treatment 3 vs. treatment 1. There was no evidence (P &gt; 0.05) for difference in female BW or backfat loss from d 113 of gestation until weaning. Average total born and born alive piglet birth weight was greater (P &lt; 0.05) in gilts fed treatment 2 or 3 vs 1, with no evidence (P &gt; 0.05) for difference in average piglet birth weight in sows, or weaning weight in gilts and sows. Piglet survival after cross-foster to weaning was improved (P &lt; 0.05) in sows fed treatment 2 vs. 1 or 3, but not in gilts. Providing high Lys and energy intake from d 107 or 113 to farrowing increased birth weight in gilts, while providing high Lys and energy intake from d 113 increased pre-weaning piglet survival in sows.

PSII-5 Carcass characteristics and growth performance of market pigs fed reduced lysine diets in bedded hoop barns

Abstract A 2 × 2 × 2 factorial design was used to compare the effect of SID Lys:ME concentration (current vs. reduced), stocking density (1.30 vs. 4.05 m2/pig), and harvest month (August vs. March) on pigs raised in bedded hoop barns in Western Iowa. For each harvest month, 420 pigs produced from the mating of Duroc boars (Choice Genetics; West Des Moines, IA) to Camborough females (PIC; Hendersonville, TN) were sorted into 12 pens. Six pens were inside 3 large-scale (9.1 × 18.3 m) hoop barns and were stocked with 64 pigs/pen (32 barrows and 32 gilts; 1.30 m2/ pig). Six pens were inside 3 small-scale (6.0 × 10.8 m) hoop barns and were stocked with 6 pigs/pen (3 barrows and 3 gilts; 4.05 m2/pig). Within each stocking density, pens were randomly assigned to 1 of 2 diets which were fed in 2 phases. Corn-soybean meal diets were formulated to deliver 2.94 or 2.34 g SID Lys per Mcal ME in phase 1 (72.6–95.0 kg) and 2.34 or 1.76 g SID Lys per Mcal ME in phase 2 (&gt; 95.0 kg). Pigs were individually weighed every 28 days and feed disappearance was recorded. When pigs in a pen averaged 129.3 kg the entire pen of pigs were harvested. A single chop (last-rib location; 2.54 cm thick) was collected from each carcass to assess pork quality. Pigs harvested in the summer grew faster, more efficiently, and with more intramuscular fat than those harvested in winter (P-value ≤ 0.05) but had lower 10th rib pH (P-value &lt; 0.0001). Pigs allotted 4.05 m2/pig grew more efficiently but had reduced last rib pH as compared to pigs stocked at 1.30 m2/pig (P-value &lt; 0.05). Reducing SID Lys:ME did not impact growth performance or carcass characteristics (P-value &gt; 0.10). Lower concentrations of SID Lys:ME may be adequate for pigs housed in bedded hoop barns but further study is warranted.

373 Efficiency of standardized ileal digestible lysine utilization for whole body protein retention in pregnant gilts and sows during early and mid gestation

Abstract NRC (2012) gestating sow model assumes the efficiency of AA use is constant across gestation, which may not reflect changes in metabolic demand during gestation. Efficiency of utilization is determined as the slope of the response to graded levels of test AA. Previous work reported a lack of response to graded Lys [60–90% of NRC (2012) predicted requirement] in early and mid gestation. Therefore, a study was conducted to determine efficiency of SID Lys utilization for whole body protein retention in gilts and sows during early (d 48–52) and mid (d 75–79) gestation. Four isocaloric (3,373 kcal ME/kg) and isoproteic (12.75 % CP) diets containing 40, 50, 60, and 70% of NRC (2012) model-predicted daily SID Lys requirement (10.1 and 9.3 g/d in early and mid gestation, respectively) were randomly assigned to 50 females (PIC 1050; 12 gilts, 21 Parity 1, 17 Parity 2). Dietary indispensable AA contents were set to meet 100–200% of AA:Lys ratios. Whole body nitrogen (N) retention was based on N-balance studies in early and mid gestation (7-d diet adaptation and 5 d total urine collection and grab fecal sampling). Lysine efficiency was determined by simple linear regression using PROC GLM procedure of SAS. Reproductive performance data were analyzed using PROC MIXED procedure of SAS. Reproductive performance of sows (birth weight, born alive, stillborn, and mummies) was not different by parity or diet. Whole body N and SID Lys retention increased linearly (P &lt; 0.0001) with increasing SID Lys intake in early and mid gestation. Efficiency of Lys utilization in early gestation was 0.60, 0.46, and 0.50, and in mid gestation 0.58, 0.44, and 0.48 for gilts, parity 1, and parity 2 sows, respectively. Parity may play a greater role in efficiency of AA use than stage of gestation.

PSV-2 Effects of protease on growth performance, fecal gas emission of 25- to 55-kg pigs fed low or high density diets

Abstract Volatility in feed ingredient prices prompts animal nutritionists to evaluate alternative methods to control feed costs. The objective of this study was to evaluate the effects of protease in growing pigs fed either high or low-density diets. A total of 140 pigs [(Landrace×Yorkshire)×Duroc] were used in a 6-wk study with an initial BW of 24.1 ± 0.02 kg equally distributed in 7 pens per treatment fed one of the following treatments: High-density diet with 3400 kcal ME/kg, 19.5% CP, and 0.85% SID Lys; High-density diet + 125 g/t Jefo Protease (Jefo, Canada); Low-density diet with 3300 kcal ME/kg, 17.6% CP, and 0.83% SID Lys; and Low-density diet + 125 g/t Jefo Protease. Diets were corn, soybean meal-based with 12% rice bran and 8% wheat bran. Data were subjected to statistical analyses as a completely randomized design using a 2 × 2 factorial arrangement with pen as the experimental unit. Differences among treatment means were determined using Duncan’s multiple range test with level of significance at P ≤ 0.05. High-density diets (P = 0.01) and protease supplementation (P = 0.05) significantly improved G:F in pigs (Table 1) compared to low-density diets and no protease supplementation. NH3 and H2S gas emission tended to be lower (P ≤ 0.10) in diets supplemented with protease. There were no statistical differences (P &gt; 0.10) in initial weight, final weight, ADG, and ADFI. In conclusion, protease supplementation and high density diets improved G:F in 25- to 55-kg pigs.

119 Bioavailability of L-Methionine in comparison to DL-Methionine for nitrogen retention of weaned and growing pigs

Abstract Two nitrogen (N) balance studies were conducted to compare the relative bioavailability (RBV) of L-Met with DL-Met as Met sources in young pigs. In each experiment, 42 barrows (PIC; initial BW in Exp. 1: 10.7 kg and Exp. 2: 20.5 kg) were allotted to 7 experimental diets with 6 pigs per treatment. The basal diets (diet 1) were formulated based on corn and soybean meal being deficient in Met, but adequate for the other AA (Exp. 1: 0.24% standardized ileal digestible [SID] Met; 0.53% SID Met + Cys; 1.30% SID Lys; Exp 2: 0.23% SID Met; 0.47% SID Met + Cys; 1.15% SID Lys). Three graded levels of DL-Met and L-Met (0.03, 0.06 and 0.09%) were supplemented to the basal diet on top to create diets 2 to 7 for both studies. In Exp.1, N retention (% of N absorbed) increased linearly (P &lt; 0.05) with supplementation with both Met sources. The slope-ratio regression estimated the RBV of 106% [95% confidence interval (CI): 39 to 173%] for N retention (% of absorbed) on an equi-molar basis. In Exp. 2, N retained (g/d), N retention (% of N intake and % of N absorbed) increased linearly (P &lt; 0.05) by supplementing with both Met sources. There was no effect of Met sources on all N balance parameters in both studies. The slope-ratio estimated the RBV of 89% (95% CI: -28 to 206%) for N retained (g/d), 95% (95% CI: 13 to 177%) for N retention (% of N intake) and 94% (95% CI: 20 to 167%) for N retention (% of N absorbed), respectively on an equi-molar basis. In conclusion, the 95% CI for the RBV of L-Met covers 100%, indicating the RBV of L-Met is not different from that of DL-Met as a Met source for weaned and growing pigs.