Standardized Ileal Digestible Lysine Research Articles

Dietary lysine affects amino acid metabolism and growth performance, which may not involve the GH/IGF-1 axis, in young growing pigs1.

Lysine is the first limiting amino acid (AA) in typical swine diets. Our previous research showed that dietary lysine restriction compromised the growth performance of late-stage finishing pigs, which was associated with the changes in plasma concentrations of nutrient metabolites and hormone insulin-like growth factor 1 (IGF-1). This study was conducted to investigate how dietary lysine restriction affects the plasma concentrations of selected metabolites and three anabolic hormones in growing pigs. Twelve individually penned young barrows (Yorkshire × Landrace; 22.6 ± 2.04 kg) were randomly assigned to two dietary treatments (n = 6). Two corn and soybean meal based diets were formulated to contain 0.65% and 0.98% standardized ileal digestible lysine as a lysine-deficient (LDD) and a lysine-adequate (LAD) diets, respectively. During the 8-week feeding trial, pigs had ad libitum access to water and their respective diets, and the growth performance parameters including average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F) were determined. At the end of the trial, jugular vein blood was collected for plasma preparation. The plasma concentrations of free AA and six metabolites were analyzed with the established chemical methods, and the hormone concentrations were analyzed with the commercial ELISA kits. Data were analyzed with Student's t-test. The ADG of LDD pigs was lower (P < 0.01) than that of LAD pigs, and so was the G:F (P < 0.05) since there was no difference in the ADFI between the two groups of pigs. In terms of free AA, the plasma concentrations of lysine, methionine, leucine, and tyrosine were lower (P < 0.05), while that of β-alanine was higher (P < 0.01), in the LDD pigs. The total plasma protein concentration was lower (P < 0.02) in the LDD pigs, whereas no differences were observed for the other metabolites between the two groups. No differences were observed in the plasma concentrations of growth hormone (GF), insulin, and IGF-1 between the two groups as well. These results indicate that the lack of lysine as a protein building block must be the primary reason for a reduced body protein synthesis and, consequently, the compromised G:F ratio and ADG. The changes in the plasma concentrations of total protein and four AA suggest that the compromised growth performance might be associated with some cell signaling and metabolic pathways that may not involve the GH/IGF-1 axis.

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.

Effects of Timing and Amount of Feed Prior to Farrowing on Sow and Litter Performance Under Commercial Conditions

A total of 727 mixed parity (mean = 3.8) sows were used to evaluate the effects of timing and size of meals before farrowing on sow and litter performance. Upon entry to the farrowing house (d 113), sows were blocked by weight within parity and allotted to 1 of 3 feeding management strategies until farrowing: 1) 6.0 lb lacta­tion diet (1.15% standardized ileal digestible lysine and 1,150 kcal/lb NE) once daily at 0700 h; 2) 4 daily meals of 1.5 lb (0100 h, 0700 h, 1300 h, 1900 h); 3) ad libitum lactation diet and encouraged to consume feed at 0100 h, 0700 h, 1300 h, and 1900 h. After farrowing, all sows were provided lactation diet ad libitum until weaning. Data were analyzed for treatment effects within parity category in a mixed model with block as a random effect. Feeding sows ad libitum before farrowing tended to reduce sow body weight loss (P = 0.077) and reduce backfat loss (P = 0.003) from entry into the farrowing house until weaning compared to sows fed 4 daily meals, with sows fed once daily intermediate. Litter gain from 24 h to weaning tended to be greater (P = 0.064) in sows fed ad libitum or 4 times daily prior to farrowing compared to sows fed one meal. Piglet weaning weight increased (P = 0.050) in sows fed ad libitum before farrowing compared to those fed one meal, with those fed 4 times daily intermediate. There was no evidence for difference in farrowing duration, stillborn rate, colostrum yield, or 24 h piglet survival regardless of treatment. However, from 24 h after farrowing to weaning, sows fed one daily meal prior to farrowing had an increased (P = 0.012) percentage of fall-behind pigs compared to sows fed ad libitum, and increased (P = 0.027) preweaning mortality compared to sows fed four daily meals, resulting in reduced (P = 0.006) weaned percentage compared to sows fed four daily meals. There was no evidence for difference (P > 0.10) in subsequent reproductive performance regardless of treatment. In conclusion, when sows were fed ad libitum from 2 to 3 days before farrowing there was an observed improvement in sow body weight and backfat maintenance, and piglet weaning weight during lactation. Increased frequency of meals prior to farrowing improved the survival of pigs to weaning compared to sows fed a single meal prior to farrowing.

Improving the estimation of amino acid requirements to maximize nitrogen retention in precision feeding for growing-finishing pigs

Precision feeding requires a mathematical model to estimate standardized ileal digestible (SID) lysine (Lys) requirements (SIDLysR) in real time. However, this type of model requires constant calibration updates. The objective of this study was to review the calibration of the model used to estimate the real-time Lys requirements of individual growing-finishing pigs. A digestibility trial (n = 10) was conducted to evaluate amino acids digestibility during the growing and finishing phases. Additionally, 120 pigs were used in two 28-day growth experiments conducted as completely randomized design with growing (25 ± 2.1 kg BW, n = 60; 10 pigs per treatment) or finishing barrows (68.1 ± 6 kg BW, n = 60; 10 pigs per treatment). In each experiment, the pigs were divided into six equal treatment groups and fed 60%, 70%, 80%, 90%, 100% or 110% of their estimated individual SIDLysR. The Lys requirement of each pig was estimated daily using a real-time model. Body composition was measured with dual-energy X-ray densitometry on day 1 and 28 of the experiments. Average daily feed intake increased quadratically (P < 0.05) during both growth phases. Maximum average daily gain (ADG) (0.98 kg) and maximum protein deposition (PD; 170 g/day) were observed in growing pigs fed 100% of the estimated SIDLysR (P < 0.001). During the growing period, PD in BW gain (17% to 19%) and N efficiency (52% to 65%) increased linearly (P < 0.01) with increasing inclusion rates of SID Lys. Finishing pigs had maximum ADG (1.2 kg/day) when they were fed 100% of the requirements. However, the amount of protein in BW gain (13% to 16%) and N efficiency (40% to 55%) increased linearly (P < 0.01) with increasing inclusion rates of SID Lys. In conclusion, the model proposed for precision feeding is correctly calibrated to predict SIDLysR that maximize PD and ADG of average pigs from 25 to 50 kg BW. Still, there is an opportunity to improve the estimation of SIDLysR and N retention in individual pigs by better representing the individual proportion of protein in BW gain and the factors controlling the efficiency of Lys utilization in individual pigs.

Determining the Phosphorus Release Curve for Smizyme TS G5 2,500 Phytase in Nursery Pigs

A total of 280 nursery pigs (DNA 241 × 600, initially 22.8 lb) were used in a 21-d growth trial to determine the available P (aP) release curve for Smizyme TS G5 2,500 (Origination, LLC., Maplewood, MN). Pigs were weaned at approximately 21 d of age, randomly allotted to pens based on initial body weight (BW), and fed common starter diets. On d 21 post-weaning, considered d 0 of the study, pens were blocked by BW and randomly allotted to 1 of 7 dietary treatments with 5 pigs per pen and 8 pens per treatment. Seven 1-ton batches of basal diet were manufactured and subsequently divided to be the major portion of experimental diets. Dietary treatments were formu­lated to include increasing aP derived from either an inorganic P source (0.11%, 0.19%, or 0.27% from monocalcium P) or increasing phytase (250, 500, 1,000, or 1,500 FTU/ kg). Diets were corn-soybean meal-based and contained 1.24% standardized ileal digestible (SID) lysine with other amino acids set to meet or exceed NRC5 require­ment estimates. Prior to beginning the 21-d study, all pigs were fed the negative control diet containing 0.11% aP for a 3-d period (d 18 to 21 post-weaning). Diets containing phytase were submitted for complete phytase analysis (Eurofins Scientific Inc., Des Moines, IA) using the AOAC official method 2000.12,6 and analyzed concentrations were 265, 470, 1,000, or 1,450 FTU/kg. On d 21 of the experiment, the pig closest to the mean BW in each pen was euthanized and the right and left fibula were collected to determine bone ash with one fibula defatted and the other not prior to ashing. Overall (d 0 to 21), pigs fed increasing aP from inorganic P had improved (linear, P < 0.01) performance across all response criteria measured. When using both the defatted and non-defatted bone mineral procedures, pigs fed increasing aP from inorganic P had increased (linear, P < 0.01) bone ash weights and percentage bone ash. Pigs fed increasing phytase had increased (linear, P < 0.01) bone ash weights and percentage bone ash (linear and quadratic, P < 0.05). The aP release increased (linear, P < 0.01) up to the highest phytase dose when using gain-to-feed ratio (G:F), bone ash weight, or defatted percentage bone ash as indicators of release. When using average daily gain and non-defatted percentage bone ash, aP release increased in a linear and quadratic fashion (P < 0.01). In conclusion,

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.

PSIX-30 Effects of dietary lysine restriction on plasma amino acid profile and growth performance of growing pigs

Abstract Muscle growth requires a constant supply of free amino acids (AAs) from blood stream. Thus, a balanced blood plasma AA profile is critical for optimizing the growth performance of pigs. This research was conducted to study how dietary lysine restriction affects the plasma AA profile in growing pigs. Twelve crossbred young barrows (initial BW 22.6 ± 2.04 kg) were individually penned in an environment controlled barn. Pigs were assigned to one of the two dietary treatments according to a completely randomized experiment design (n = 6). Two corn- and soybean meal-based diets containing 0.65% (Diet I, lysine-deficient) and 0.98% (Diet II, lysine-adequate) standardized ileal digestible lysine were fed to the pigs. The growth performance of pigs with parameters including ADG, ADFI, and G:F was measured for the 8 week feeding trial. At the end of the trial, jugular vein blood was collected and the plasma samples were obtained for AA analysis using HPLC methods. Data were statistically analyzed using Student’s t-test. As expected, the ADG of Diet I pigs was lower (P &amp;lt; 0.01) than Diet II pigs, and so was G:F (P &amp;lt; 0.05) since there was no difference in ADFI between the two groups. In terms of plasma free AAs, the concentrations of lysine, methionine, leucine, and tyrosine were lower (P &amp;lt; 0.05), while the concentration of b-alanine was higher (P &amp;lt; 0.01), in Diet I vs. Diet II pigs. The concentrations of other AAs were not different (P &amp;gt; 0.05) between the two groups. It can be concluded that besides lysine, the reduced plasma supply of methionine, leucine, and tyrosine is all responsible for the reduced ADG and G:F in pigs fed the lysine-deficient diet. Whether or not the increased plasma concentration of b-alanine in lysine-deficient pigs can reduce the occurrence of PSE pork warrants further investigation.

120 Awardee Talk: Amino acid and energy requirements of high producing sows

Abstract Improvements in genetic selection, nutrition, health, and management has led to continuous improvement in sow productivity over the past 10 to 20 years. Today’s sows are more prolific with greater number of pigs gestated, nursed, and weaned per litter than in the past. Modern genotype females are also faster growing and leaner than predecessors. These changes in reproductive performance and body composition alter nutrient requirements during gestation and lactation. Gestation nutrient requirements appear to be met with approximately 11 to 12 g/d of standardized ileal digestible (SID) lysine and 5,000 to 6,000 Kcal/d NE. Providing greater lysine intake increases protein deposition and sow weight gain and may reduce stillbirth rate; however, the magnitude of economic benefit provides marginal economic response. Increasing energy and amino acid intake the last 3 to 4 days pre-farrowing appears to be a better alternative to shorten farrowing duration, increase the number of pigs born alive, and their weaning weights, than providing extra feed from d 90 of gestation through farrowing. During lactation, the goal is still to increase feed intake to minimize sow weight loss. Lysine requirement estimates in lactation seem to vary from study to study possibly reflecting the degree of sow muscle and fat catabolism. A summary of several lactation studies predicts a daily lactation requirement of 27 g SID Lys from the diet with an additional 13 g mobilized from body tissue for each 1 kg of litter growth. From a feed management standpoint, the availability of equipment to provide ad libitum consumption has been a major benefit in lactation. In conclusion, the literature suggests there are many successful ways to feed sows in gestation, peri-partum, and lactation, indicating that today’s sows are extremely resilient to nutritional challenges.

The effect of pregnancy on nitrogen retention, maternal insulin sensitivity, and mRNA abundance of genes involved in energy and amino acid metabolism in gilts.

Twenty-one of each pregnant (P) and nonserviced, nonpregnant (NP) sister-pairs of gilts were selected to investigate the effect of pregnancy on protein deposition (Pd; whole body and maternal), insulin sensitivity, and mRNA abundance of genes involved in energy and AA metabolism. Between breeding (study day 0) and day 111, P and NP gilts received 2.16 kg of the experimental diet (3.34 Mcal ME/kg, 17.6% crude protein, 0.78% standardized ileal digestible lysine) that was formulated to meet the estimated ME requirements of pregnant gilts (and meet or exceed AA requirements). Nitrogen balances were conducted on day 63 and 102 ± 0.2 of the study during 4-d periods. Blood samples were collected on day 43, 56, 71, 85, 98, and 108 ± 0.3 of the study to determine plasma concentrations of fasted IGF-1, estradiol (E2), and estrone sulfate (E1S). Frequently sampled intravenous glucose tolerance tests (FSIGTT) were conducted on day 75 ± 0.7 in 6 P and 5 NP gilts and on day 107 ± 0.4 in 17 P and 17 NP gilts and the MINMOD approach was applied to evaluate whole body insulin sensitivity and pancreatic responsiveness. Longissimus muscle (LM) and s.c. adipose tissue (AD) samples were excised from 12 P and 12 NP gilts at day 111 ± 0.4 of the study after euthanasia to determine mRNA abundance of key genes. Whole body Pd was greater (P < 0.001) at day 102 and maternal Pd was lower (P < 0.002) at day 63 and 102 for P compared to NP gilts. Plasma concentrations of E1S and E2 increased (P < 0.05) with study day for P gilts and remained constant for NP gilts, which coincided with reduced plasma concentrations of IGF-1 and increased estrogen receptor alpha (ESR1) mRNA abundance in LM of P gilts. Glucose effectiveness was not different between P and NP gilts, but whole body insulin sensitivity was lower (P = 0.004) in P compared to NP gilts on day 75 and 107, which corresponded with reduced mRNA abundances of SLC2A4, HK2, SREBF1, and FASN, and increased abundances of PDK4 and PPARGC1A in LM and AD. When fed identically, P gilts had greater whole body Pd at day 102, which reflects Pd in the pregnancy-associated tissues (at the expense of maternal Pd), likely driven by estrogen-stimulated insulin resistance in peripheral tissue and subsequent modulation of gene expression relating to glucose metabolism.

155 Effects of soybean meal level and distillers dried grains with solubles inclusion on growth performance of late nursery pigs

Abstract Two experiments were conducted to determine the effects of soybean meal (SBM) level in diets with or without distillers dried grains with solubles (DDGS) on growth performance of late nursery pigs. A total of 1,064 and 1,011 pigs (PIC 280×1050; initially 10.5 ± 0.36 and 10.9 ± 0.22 kg) were used in Exp. 1 and 2, respectively, with 21 to 27 pigs per pen. Pens were assigned to treatments in a randomized complete block design with 7 replicates per treatment per experiment. Treatments 1 to 3 were diets with 23% DDGS and 21, 27, or 35% SBM. Treatments 4 and 5 were corn-SBM diets with 27 or 35% SBM. Diets were balanced to 1.30% standardized ileal digestible lysine and 2,606 kcal of net energy/kg. Data were analyzed with the GLIMMIX procedure of SAS with pen as the experimental unit and block as random effect. There was no evidence for treatment × experiment interactions, thus data from both trials were combined. Feeding diets with 23% DDGS decreased (P = 0.033) ADFI and improved (P = 0.033) G:F compared to corn-SBM diets, which may indicate underestimation of DDGS net energy. When analyzed as a factorial with or without DDGS, pigs fed diets with 35% SBM had a tendency (P = 0.052) for increased ADG and improved (P = 0.001) G:F compared with diets with pigs fed 27% SBM. As SBM increased from 21 to 35% in diets with DDGS, ADG (linear, P = 0.001) and G:F (quadratic, P = 0.007) improved. In summary, feeding diets with increasing SBM improved growth performance in late nursery pigs.

20 Nutritional strategies to manage gilt growth and optimize lifetime productivity

Abstract Improving gilt development is key to maximizing sow longevity. How to best manage and feed gilts during development is heavily debated. A series of studies were conducted to determine the optimal feeding program for gilts during development. The hypothesis was that metabolizable energy (ME) and standard ileal digestible lysine could be varied under commercial conditions (ad libitum feeding) to optimize body weight gain and composition, age at puberty, and mammary gland development to support increased productivity of gilts. Studies were conducted in commercial production facilities in Iowa and Utah using large numbers of maternal-line gilts that were monitored, under various dietary treatments from 100 to 200 d of age, for growth, body composition, age at puberty and development of reproductive organs and mammary glands. Varying the dietary Lysine:ME ratio (g:mcal) had modest effects on growth and body composition of gilts. Likewise, development of reproductive organs was minimally affected by diet, but slower growth delayed development of terminal lobular ductal units in mammary glands. Growth rates were slowed by reducing dietary lysine:ME ratio below the requirement and increasing fiber. Gilts still had adequate growth (&gt; 600 g/d) and body composition (≥ 15 mm backfat) for good reproductive performance. Although dietary treatments did not affect the average age of puberty (205 d) or the total number of gilts that reached puberty, a greater percentage of gilts fed higher lysine diets exhibited puberty during the first 40 days of boar exposure. Gilts lost 2 to 3 mm backfat once moved from the development unit to the breeding farms, but pregnancy rates were ≥ 95%. Culling of gilts before first breeding did not vary with diet but was considerably higher than expected. Investigation of how these developmental traits affect productivity through subsequent parities is ongoing.

19 Overview of the National Pork Board replacement gilt feet and leg evaluation trial

Abstract Replacement gilt feet and leg conformation traits are subjectively evaluated at early ages (150 d) in order to select acceptable replacements. The objectives of this study were to: 1) evaluate replacement gilt feet and leg conformation (FLC) using subjective and objective measurement methods, 2) estimate objective joint angle changes over two parities, and 3) evaluate the effect of three diets differing in standardized ileal digestible (SID) lysine concentrations on FLC traits using the objective evaluation method. Crossbred Large White × Landrace gilts (n = 641) were used. Gilts were moved to GDU at 77 days-of-age and randomly allotted to three ad libitum fed dietary treatments providing similar ME but differing in SID lysine concentrations (low, medium, and high) during the grow-finisher period. All animals received common gestation and lactation diets. Feet and leg conformation traits were evaluated at 100 d, 200 d, 1st litter (392 ± 25 d) and 2nd litter (548 ± 49 d) weaning events. Subjective evaluation was done on a scale from 1 to 5. Data were analyzed using mixed linear model methods. The majority of gilts received the intermediate score (i.e. 3) when joint angles were subjectively evaluated. No differences (P ≥ 0.05) were observed for knee, front pastern and hock objective joint angles between subjective scores assigned. Differences in subjectively evaluated rear pastern (P &lt; 0.05) were observed, where objective joint angles associated with scores of ≤ 2 and 3 were lower than score of ≥ 4. There was no interaction between dietary treatment and objective evaluation time-period for any FLC traits studied (P &gt; 0.05). Females with greater knee, hock, front and rear pastern objective joint angles at 100 d of age, continued to have greater joint angles (0.2 ± 0.04 degrees; P &lt; 0.001) later in life. Front and rear pastern joint angles decreased (P &lt; 0.001) and hock joint angles increased from 100 d to end of study (P &lt; 0.001).

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.

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%.

Diet formulation method influences the response to increasing net energy in finishing pigs.

An experiment was conducted to compare the effects of increasing dietary net energy (NE) in finishing pig diets while either maintaining a standardized ileal digestible lysine:NE ratio (SID Lys:NE) or maintaining SID Lys as a constant percentage of the diet across increasing energy densities. A total of 150 pigs (Line 600 × 241; DNA, Columbus, NE; initially 35.7 kg) were used in a 91-d study. Pigs were blocked by sex and weight and randomly assigned to 1 of 5 treatments with 2 pigs per pen and 15 pens per treatment. Treatments included a low-energy control diet that was corn-soybean meal-based with added soybean hulls, and a 2 × 2 factorial arrangement of treatments with main effects of increasing dietary NE (medium or high by adding choice white grease) and formulation method (with a SID Lys:NE ratio or maintaining the same percentage SID Lys). Linear and quadratic contrasts were made using the control diet and the medium- and high-energy diets within each formulation method. Pigs and feeders were weighed approximately every 30 d to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F). At the end of the experiment, pigs were sent to a commercial processing facility for carcass data collection. From days 0 to 34 and 34 to 61, ADG and SID Lys intake increased as NE increased (linear, P < 0.05) in pigs fed diets with a Lys:NE ratio, but not for those fed the same percentage Lys. As NE increased, NE intake and G:F increased (P < 0.01) in pigs fed diets with either formulation method. From days 61 to 91, increasing NE had no effect (P > 0.10) on ADG. There was no change in G:F in pigs fed diets with the same percentage Lys (P > 0.10), but G:F decreased then increased (quadratic, P < 0.01) in response to increasing NE in pigs fed diets with a SID Lys:NE ratio. Overall, increasing dietary NE increased (linear, P < 0.001) daily NE intake and G:F (linear, P < 0.018) with either formulation method. However, SID Lys intake, ADG, and hot carcass weight only increased (linear, P < 0.01) when a SID Lys:NE ratio was maintained. Increasing NE without maintaining a constant SID Lys:NE ratio increased backfat depth (quadratic, P = 0.01), whereas it did not in pigs fed diets with a SID Lys:NE ratio. In conclusion, increasing dietary energy density increased NE intake and G:F regardless of formulation method. However, a SID Lys:NE ratio must be maintained to achieve increased ADG and minimize fat deposition.

Dynamic modeling of nutrient use and individual requirements of lactating sows1.

Nutrient requirements of sows during lactation are related mainly to their milk yield and feed intake, and vary greatly among individuals. In practice, nutrient requirements are generally determined at the population level based on average performance. The objective of the present modeling approach was to explore the variability in nutrient requirements among sows by combining current knowledge about nutrient use with on-farm data available on sows at farrowing [parity, BW, backfat thickness (BT)] and their individual performance (litter size, litter average daily gain, daily sow feed intake) to estimate nutrient requirements. The approach was tested on a database of 1,450 lactations from 2 farms. The effects of farm (A, B), week of lactation (W1: week 1, W2: week 2, W3+: week 3 and beyond), and parity (P1: 1, P2: 2, P3+: 3 and beyond) on sow performance and their nutrient requirements were evaluated. The mean daily ME requirement was strongly correlated with litter growth (R2 = 0.95; P < 0.001) and varied slightly according to sow BW, which influenced the maintenance cost. The mean daily standardized ileal digestible (SID) lysine requirement was influenced by farm, week of lactation, and parity. Variability in SID lysine requirement per kg feed was related mainly to feed intake (R2 = 0.51; P < 0.001) and, to a smaller extent, litter growth (R2 = 0.27; P < 0.001). It was lowest in W1 (7.0 g/kg), greatest in W2 (7.9 g/kg), and intermediate in W3+ (7.5 g/kg; P < 0.001) because milk production increased faster than feed intake capacity did. It was lower for P3+ (6.7 g/kg) and P2 sows (7.3 g/kg) than P1 sows (8.3 g/kg) due to the greater feed intake of multiparous sows. The SID lysine requirement per kg of feed was met for 80% of sows when supplies were 112 and 120% of the mean population requirement on farm A and B, respectively, indicating higher variability in requirements on farm B. Other amino acid and mineral requirements were influenced in the same way as SID lysine. The present modeling approach allows to capture individual variability in the performance of sows and litters according to farm, stage of lactation, and parity. It is an initial step in the development of new types of models able to process historical farm data (e.g., for ex post assessment of nutrient requirements) and real-time data (e.g., to control precision feeding).

Efficiency of utilizing standardized ileal digestible lysine and threonine for whole-body protein retention in pregnant gilts during early, mid-, and late gestation1.

Two experiments were conducted to determine the efficiency of utilizing SID Lys and Thr for whole-body protein retention (kSIDLys and kSIDThr) in pregnant gilts. In Exp. 1, 45 gilts (158.0 ± 8.0 kg at day 39.4 ± 1 of gestation) in 2 groups were used in a 3-period nitrogen (N)-balance study. Gilts were assigned to 1 of 4 diets set to provide 60, 70, 80, and 90% of predicted daily SID Lys requirement for protein retention (NRC, 2012) in each of early (day 41 to 52, 10.44 g/d), mid- (day 68 to 79, 9.60 g/d), and late gestation (day 96 to 107, 16.04 g/d). Diets contained 3,300 kcal ME/kg and 11.6% CP; given at a rate of 2.13 kg/d in early and mid-gestation and at 2.53 kg/d during late gestation. The 12-d balance period (7-d adaptation; 5-d urine and fecal collection) was based on total urine collection using urinary catheters and determination of fecal N digestibility using indigestible marker. The SID Lys required for whole-body protein retention was estimated using the NRC (2012) model and the predicted Lys content of each gestation pool. Lysine efficiency at each diet Lys level was calculated as the ratio of daily Lys retention and SID Lys intake. The linear and quadratic response in whole-body N and Lys retention and Lys efficiency for each balance period was determined. The kSIDLys was determined from the slope generated by regressing whole-body Lys retention vs. SID Lys intake, with y-intercept set to 0. In Exp. 2, 45 gilts (165.7 ± 13.6 kg at day 39.1 ± 2 of gestation) were assigned to 1 of 4 diets set to provide 60, 70, 80, and 90% of the predicted daily SID Thr requirement for protein retention in each of early (6.46 g/d), mid- (6.05 g/d), and late gestation (9.75 g/d). Animal management, N-balance procedure, data collection and calculation, and statistical analyses were patterned from Exp. 1. In early and mid-gestation, whole-body N retention, as well as Lys and Thr retention, was not affected by the dietary SID Lys and Thr. In late gestation, there was a linear increase (P < 0.001) in whole-body N, Lys and Thr retention. The kSIDLys and kSIDThr in late gestation were determined to be 0.54. The lack of response in whole-body protein retention in early and mid-gestation may in partly reflect excess Lys and Thr intake. Lysine and Thr efficiency calculated at the lowest dietary Lys and Thr was 0.49 and 0.32 in early gestation and 0.61 and 0.52 in mid-gestation, respectively. Based on the available evidence, kSIDLys and kSIDThr do not appear to be constant throughout gestation.

Effect of dietary standardized ileal digestible lysine and copper density on growth performance, nutrient digestibility, blood profiles, fecal microbiota, backfat thickness and lean meat percentage in growing pigs

This study was conducted to evaluate the effect of dietary standardized ileal digestible lysine (SID Lys) and copper (Cu) density on growth performance, nutrient digestibility, blood profiles, fecal microbiota, backfat thickness and lean meat percentage in growing pigs. A total of 240 castrated male growing pigs [(Yorkshire × Landrace) × Duroc)] with an average BW of 22.7 ± 0.11 kg were used in this 42-day trial. Pigs were randomly allocated to 3 treatments plus control based on the BW. Basal diet contained 100% SID Lys of the estimated NRC (2012) requirement and 17 mg/kg Cu. Dietary treatments included different SID Lys of the estimated NRC (2012) requirement (100, 103 and 106%) with an extra 150 mg/kg supplemental Cu. Final BW, ADG and estimated SID Lys intake in pigs fed diets with 103 and 106% SID Lys and supplemental Cu were increased (P < 0.05) compared with those fed control diet. With the increasing SID Lys level, final BW, ADG, ADFI, G: F and estimated SID Lys intake in supplemental Cu treatments increased (P < 0.05) linearly. The apparent digestibility of dry matter (DM), nitrogen (N) and gross energy (GE) in supplemental Cu treatments showed a linear increase (P < 0.05) in response to increasing SID Lys level. Pigs fed control diet had higher (P < 0.05) blood urea nitrogen (BUN) than those fed diets with 103 and 106% SID Lys and supplemental Cu. The creatinine in supplemental Cu treatments with 100% SID Lys group was increased (P < 0.05) compared with control, and the creatinine in supplemental Cu treatments increased (P < 0.05) linearly with the increasing SID Lys level. Fecal Escherichiacoli (E. coli) counts were linearly (P < 0.05) decreased by supplemental Cu treatments with the increasing SID Lys level. Taken together, increasing SID Lys in 150 mg/kg supplemental Cu treatments improved growth performance, nutrient digestibility, backfat thickness, but decreased fecal E. coli counts in growing pigs.

Optimal dietary standardized ileal digestible lysine and crude protein concentration for growth and carcass performance in finishing pigs weighing greater than 100 kg1,2.

Three experiments were conducted to determine the optimal dietary standardized ileal digestible (SID) lysine and CP concentrations for finishing pigs over 100 kg BW. In Exp. 1, 253 pigs (DNA 600 × 241, initially 102.0 kg) were used in a 23-d trial with 7 to 8 pigs per pen and 8 pens per treatment. Dietary treatments contained 4 SID lysine concentrations (0.45, 0.55, 0.65, or 0.75%). To formulate the experimental diets, a corn-soybean meal diet with 0.45% SID lysine was formulated without L-lysine HCl. Then, a corn-soybean meal diet containing 0.75% SID lysine was formulated including 0.23% L-lysine HCl. The 0.45 and 0.75% SID lysine diets were blended to provide the 0.55 and 0.65% SID lysine diets. Increasing SID lysine increased (quadratic, P < 0.05) ADG and ADFI with pigs fed 0.55% SID lysine having the greatest final BW. Marginal improvements in gain:feed (G:F; quadratic, P = 0.058) and carcass yield (linear, P = 0.051) and reduction in backfat (quadratic, P = 0.074) were also observed with increasing SID lysine. The quadratic polynomial models predicted maximum ADG and G:F at 0.62 and 0.63% SID lysine, respectively. The broken-line linear model predicted no further improvement in G:F over 0.55% SID lysine. In Exp. 2, 224 pigs (PIC 327 × 1050, initially 109.4 kg) were used in a 20-d trial with 7 pigs per pen and 7 to 8 pens per treatment. Dietary treatments included 4 concentrations of CP (10, 11, 12, or 13%) that were formed by reducing the amount of L-lysine HCl in a corn-soybean meal diet. Increasing CP increased (linear, P < 0.05) ADG and ADFI with the greatest responses observed in pigs fed the diet with 12% CP. Increasing dietary CP also improved (linear, P < 0.05) G:F, final BW, and hot carcass weight (HCW). In Exp. 3, 238 pigs (DNA 600 × 241, initially 111.8 kg) were used in a 26-d trial with 7 to 8 pigs and 6 pens per treatment. Dietary treatments included 5 concentrations of CP (9, 10, 11, 12, or 13%). Increasing CP improved (quadratic, P < 0.05) ADG and G:F with the greatest response observed in pigs fed 13% CP. Increasing CP marginally increased (quadratic, P < 0.074) HCW, with the greatest response observed in pigs fed 12% CP. In conclusion, the SID lysine requirement for pigs from 100 to 122 kg was 0.55 to 0.63% depending on the response criteria with performance maximized with diets containing 12 to 13% CP.

Impact of feed intake during late gestation on piglet birth weight and reproductive performance: a dose-response study performed in gilts

The effects of increasing feed intake (1.8, 2.3, 2.8, and 3.3 kg/d) during late gestation of gilts on piglet birth weight and female reproductive performance were evaluated. A total of 977 gilts were fed a diet based on corn-soybean meal (3.29 Mcal ME per kg and 0.64% standardized ileal digestible lysine) from day 90 of gestation until farrowing. Gilts were weighed on days 90 and 112 of gestation, at farrowing and weaning. Born alive and stillborn piglets were weighed within 12 h of birth. Colostrum yield (CY), lactation feed intake, and litter growth rate were measured in a randomly selected subsample of 245 gilts. The data were analyzed using generalized linear mixed models. As expected, gains in body weight (BW) were different at day 112 (P < 0.001) with the greatest values observed in the 3.3 kg/d treatment. As feed intake increased during late gestation, BW, body condition score (BCS), backfat (BF), and Caliper unit also increased between day 112 and weaning (P < 0.001). No differences were found among treatments in total number of piglets born, mummified fetuses, sum of born alive and stillborn piglets, and within-litter birth weight CV (P > 0.05). Tendencies for quadratic effect of feed intake were observed for born alive piglets (P = 0.079), average birth weight of piglets (P = 0.083), and litter weight (P = 0.059). Gilts with lower feed intake during late gestation had reduced percentages of stillborn piglets than gilts with greater feed intakes. The CY decreased linearly (P < 0.05) as the feed intake was increased. No differences among treatments were found at weaning in individual piglet weight and litter weight, as well as in percentage of weaned piglets (P > 0.05). Lactation feed intake decreased as gestation feeding level increased (P < 0.05). No differences in the subsequent cycle were observed among treatments for farrowing rate, retention rate up to the next farrowing, number of total piglets born, born alive, stillborn piglets, and mummified fetuses (P > 0.05). In conclusion, increased feed intake from day 90 of gestation until farrowing resulted in increased maternal BW gain and stillborn rate, but reduced CY and lactation feed intake. A slight increase in birth weight was observed for the 2.3 kg/d treatment. Furthermore, litter growth and subsequent female reproductive performance were not affected by feed intake during late gestation.