Digestible Lysine Requirement Research Articles

20 Assessment of lysine requirement in lipopolysaccharide-challenged pigs

Abstract This study was conducted to investigate the effect of immune challenge (IC) on digestible lysine (Lys) requirement of growing pigs using the Goettingen approach. Twenty-four 19kg-pigs were used in three nitrogen balance (NB) trials. The trials were performed in a complete randomized block design, with six nitrogen levels (NL), two sanitary status (control and IC) and two individual replicates per treatment (6 x 2 x 6). Dietary NL concentration ranged from 1.06 to 4.48 % in DM, being Lys limiting in all the levels assessed. For two consecutive days, Escherichia coli lipopolyssacharide (LPS) was intramuscular injected in challenged pigs at 30 and 34μg/kg. Data were fitted to nonlinear models to estimate nitrogen requirement for maintenance (NMR) and the maximum nitrogen deposition (NDmaxT). Both information were associated with the maximum nitrogen retention (NRmaxT), Lys efficiency (bc-1) and nitrogen retention (NR) to determine Lys requirements as follows: Lys = (lnNRmaxT-ln(NRmaxT-NR))/(16×bc−1). The NRM of pigs from control group was estimated in 152mg of N/kg of BW0,75/day, whereas LPS-challenged pigs had such requirements estimated in 197 N/kg of BW0,75/day. NDmaxT was estimated in 3525 and 2078mg of N/kg BW0,75/day in for pigs form control and LPS-challenged group, respectively. Requirements for Lys were estimated based on 68% and 54% of NDmaxT, being such percentage based on the mean value of ND for each group. Pigs from control group had the requirements for Lys estimated in 1.42 and 1.58%, based on a feed intake of 1000 and 900g/day, respectively, whereas Lys requirements of LPS-challenged pigs were estimated in 0.76 and 0.84%, based 893 and 803g/day of feed intake, respectively. Compared with control, LPS group exhibited a reduction of approximately 11% in feed intake. The model enables to estimate Lys requirement, taking into account protein deposition potential, feed intake, and immune challenge.

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

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

Digestible lysine requirement for Tambaqui (Colossoma macropomum) juveniles using the diet dilution technique

This study aimed at determine the digestible lysine requirement of tambaqui juveniles using the diet dilution technique. A total of 250 juveniles tambaqui with an initial mean of 22.99 ± 1.06 g were used in a dose-response experiment with five levels of digestible lysine (0.865, 1.125, 1.383, 1.644 and 1.903%) and five replication per treatment. The digestible lysine levels evaluated did not influence the feed intake (P > 0.05), but there was a linear effect (P < 0.05) on the digestible lysine intake. Quadratic effects on weight gain, specific growth rate, feed conversion ratio, and body protein deposition were observed, estimating the requirements at 1.39; 1.37; 1.37 and 1.58% digestible lysine, respectively. Since there was no effect on the feed intake and, consequently, on energy consumption, the improvements in feed conversion ratio and weight gain occurred owing to the better amino acid balance of the rations in the requirement of digestible lysine. The requirement for digestible lysine in the diet for tambaqui juveniles was determined at 1.58% by the body protein deposition, which corresponds to 5.76% dietary crude protein.

Simulated amino acid requirements of growing pigs differ between current factorial methods

Significant differences in the estimation of amino acid requirements exist between the available factorial methods. This study aimed to compare current factorial models used to estimate the individual and population standardised ileal digestible (SID) lysine (Lys) requirements of growing pigs during a 26-day feeding phase. Individual daily feed intake and BW data from 40 high-performance pigs (25-kg initial BW) were smoothed by linear regression. Body weight gain was constant (regression slope not different from 0) for all the pigs. The CV of the SID Lys requirements ranged from 22% at the beginning of the trial to 8% at the end. The population Brazilian tables (BT-2017) and National Research Council (NRC-2012) SID Lys requirements for the average pig were 16% higher than the average requirement estimated by the individual precision-feeding model (IPF), but similar to the estimated for the population assuming that population requirements are those of the 80th-percentile pig of the population (IPF-80). Meaning that, the IPF-80, BT-2017, and NRC-2012 models would yield similar recommendations when pigs are group-fed in conventional multi-phase systems. Additionally, the IPF-80 estimates are independent of the phase length, whereas the BT-2017 and NRC-2012 models use average population values in the middle of the feeding phase for the calculations and therefore, conventional requirement estimations decrease as the length of the feeding phase increases. In conclusion, the BT-2017 and NRC-2012 methods were calibrated for maximum population responses, which explains why these methods yield higher values than those estimated for the average pig by the IPF model. This study shows the limitations of conventional factorial methods to estimate amino acid requirements for precision-feeding systems.

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.

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.

Digestible lysine requirement for European laying quail

The experiment was carried out to evaluate the productive performance of European quails (Coturnix coturnix) in the production phase, fed with diets containing different levels of digestible lysine. A total of 175 female quails, aged 65 days, were randomly distributed in a completely randomized design with five treatments and five replicates per treatment. The animals were housed in 25 metal cages, and each cage represented an experimental parcel, with seven birds per parcel. The birds were fed the experimental rations containing 1.177, 1.217, 1.317, 1.417, and 1.517% digestible lysine. The parameters evaluated were: laying rate, mass of eggs produced, feed intake in the period, lysine intake, feed conversion per dozen and per mass. Significant differences were observed for posture rate with quadratic behavior, which indicated higher production for the level of 1.23% of digestible lysine. There was an increasing linear behavior for the feed and lysine intake, and for conversion feed per dozen and by mass, we observed quadratic behaviors. This indicates better feed conversion index when the optimal inclusion level was 1.33% and 1.404% of digestible lysine in the diet, respectively. The requirement of digestible lysine in diets for European quails is 1.404%, which corresponds to a daily intake of 421.20 milligrams of digestible lysine.

Evaluation of factorial methods to estimate lysine requirements for barrows and immunocastrated pigs

The aim of this study was to compare the digestible lysine requirements of castrated and immunocastrated pigs, generated via three factorial methods based on the performance of these animals. This study was divided into two steps. In the first step, an experiment was conducted to evaluate the performance of castrated and immunocastrated pigs. In the second step, the performance data were used to evaluate the nutritional requirements generated by three factorial methods. A total of 48 pigs (24 barrows and 24 immunocastrated) from a commercial line, with an average initial body weight of 29.3 ± 1.9 kg at 75 days of age and a final body weight of 129.9 ± 9.0 kg at 177 days of age, were used. The experimental diets were formulated based on the ideal protein concept in a nutritional programme of four diets. Immunocastrated pigs had lower feed intake, greater weight gain and better feed conversion in relation to physically castrated pigs, but after the application of the second dose of the vaccine, there was an increase in feed intake. There was a difference between the factorial methods used to estimate the lysine requirement of growing and finishing pigs, especially considering lysine deposition efficiency. According to the tested methods, entire males submitted to immunocastration require a higher amount of lysine, compared with surgically castrated pigs.

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).

Determining the digestible lysine requirement of 22- to 47-week-old Lohmann laying hens using an increasing protein titration methodology

A laying hen trial was conducted from 22 to 47 wk of age to determine the digestible lysine (DLYS) requirement of laying hens by using an increasing CP titration method. A total of 896 Lohmann LSL-Lite caged layers (22 wk of age) were allotted to 8 dietary treatments and each treatment had 8 replications of 14 hens. The first 7 experimental diets initially contained DLYS levels increasing from 0.565 to 0.980% with respective protein levels increasing from 13.8 to 21.7%. Dietary treatment 8 was a control diet which was calculated to contain 18.6% CP and 0.807% DLYS. These DLYS levels were reduced from 0.468 to 0.845% for diets 1 to 7 (0.688% for diet 8) at week 12 so that greater differences in production parameters could be obtained. Increasing DLYS levels had a significant (P < 0.05) effect on egg production, egg weight, egg mass, and feed efficiency. However, DLYS levels had no significant effect on egg component measurements such as percentage of yolk, white, and solids. Broken line regression, maximum of the quadratic polynomial (QP max) regression, and the intercept of the broken line and QP regressions were used to estimate the DLYS requirement. Broken line regression yielded the lowest requirement and QP max regression yielded the highest, with the intercept of the broken line and QP regressions yielding an intermediate requirement estimate. The DLYS requirements were consistently lower for egg production than for egg mass and feed efficiency. For egg mass and feed efficiency, DLYS requirements were 655 and 690, 817 and 866, and 706 and 778mg/hen/d for the broken line, QP max, and the intercept of the broken line and QP regressions, respectively.

Evaluation of standardized ileal digestible lysine requirement for 8-20kg pigs fed low crude protein diets.

Two experiments were conducted to determine the standardized ileal digestible lysine (SID Lys) requirement for weaned pigs fed with low crude protein (CP) diet. In Experiment 1, 144 pigs were fed a normal CP (20%) diet with 12.3g/kg SID Lys and five low CP (18.5%) diets providing SID Lys levels of 9.8, 11.1, 12.3, 13.5, and 14.8g/kg, respectively, for 28days. Reducing dietary CP from 20% to 18.5% enhanced (p<0.05) the growth performance. The average daily gain (ADG) and gain to feed ratio (G:F) increased (linear and quadratic; p<0.05), serum urea nitrogen (SUN) decreased (linear and quadratic; p<0.05) as SID Lys increased. The SID Lys levels required to maximize ADG and optimize G:F were 12.8 and 13.1g/kg using a curvilinear plateau model, and to minimize SUN was 13.4g/kg using a two-slope broken-line model, which averaged 13.1g/kg SID Lys. In Experiment 2, 18 pigs were used in a 12-day N balance trial and received the same diets of Experiment 1. Total N excretion was decreased when dietary CP reduced and further decreased when SID Lys increased. Collectively, 1.5% dietary CP reduction improved the growth performance and decreased the N excretion; the optimal SID Lys requirement was at 13.1g/kg of 8-20kg pigs fed with 18.5% CP diet.

PSIII-31 Standardized ileal digestible lysine requirement of Ross 308 broilers at the age of 10 to 21 days.

PSIII-31 Standardized ileal digestible lysine requirement of Ross 308 broilers at the age of 10 to 21 days.

Digestible Lysine Requirements the Performance, Carcass Traits and Breast Meat Quality of Slow-Growing Broilers

ABSTRACT Three experiments were conducted to estimate the digestible lysine requirements of slow-growing broilers on their performance, carcass traits, and breast meat quality. Different broilers were evaluated in each experiment. In Experiment 1, broilers were evaluated from 29-49 days of age (grower phase I), in Experiment 2, from 50 to 69 days old (grower phase II), and in Experiment 3, from 70-84 days old (finisher phase). A completely randomized design with five treatments of four replicates each was applied in all experiments. The following dietary digestible lysine values were investigated: 0.871, 1.011, 1.151, 1.291 and 1.431% in Experiment 1; 0.803, 0.943, 1.083, 1.223 and 1.363% in Experiment 2; and 0.766, 0.906, 1.046, 1.186 and 1.326% in Experiment 3. In all three experiments, digestible lysine values quadratically affected feed intake, weight gain, and feed conversion ratio. Lysine intake linearly increased with increasing digestive lysine values, whereas lysine utilization efficiency linearly decreased. Lysine requirements for maximum feed intake (1.298, 1.109, 1.150%), weight gain (1.183, 1.199, 1.162%), and feed conversion ratio (1.203, 1.162, 1.126%) were estimated in Experiments 1, 2 and 3. Digestible lysine requirement for carcass yield were estimated as 1.162, 1.068 and 1.107% in experiments 1, 2 and 3, respectively. Lysine influenced the physical-chemical parameters broiler breast meat. Digestible lysine levels of 1.203, 1.162 and 1.126% are recommended in the diets of Redbro Plume broilers during the phases 29-49, 50-69 and 70-84 days of age to optimize feed conversion ratio.

Standardized ileal digestible lysine requirement of male broilers at the age of 0–10 days

Two experiments were conducted to determine the standardized ileal digestible (SID) lysine requirement for 10-day-old male broilers. In experiment 1, 3 experimental diets including 2 diets composed of corn or soybean meal as the sole source of amino acids and an N-free diet were used to investigate standardized ileal digestibility of amino acids in corn and soybean meal for 11-day-old broilers. A total of 480 birds were allocated to the 3 treatments with a randomized complete block design, and each treatment included 8 cages per treatment and 20 birds per cage. In experiment 2, a total of 720 1-day-old birds were used for 10 days. The birds were allocated to 6 diets and 8 blocks with a randomized complete block design to estimate the SID lysine requirements. The 6 experimental diets were based on corn-soybean meal, and the concentrations of SID lysine in the diets increased equally from 9.8 g/kg to 14.8 g/kg with a consistent ratio of other indispensable amino acids. As the SID lysine increased, the average daily gain and gain:feed ratio increased linearly and quadratically (P < 0.05). The SID lysine requirements for average daily gain and gain:feed ratio were 13.27 g/kg and 12.89 g/kg for the one-slope broken-line, 15.33 g/kg and 13.99 g/kg for the quadratic broken-line, 14.56 g/kg and 13.24 g/kg for 95% of the upper asymptote of the quadratic model, and 14.18 g/kg and 13.56 g/kg for the first intercept between the plateau of the one-slope broken-line and quadratic models, respectively. In conclusion, the SID lysine requirements for 10-day-old broiler chicks fed corn-SBM-based diets ranged from 13.27 g/kg to 15.33 g/kg for average daily gain and from 12.89 g/kg to 13.99 g/kg for gain:feed ratio.

Evaluation of the standardized ileal digestible lysine requirement of nursery pigs from 28 to 63 d of age in a three-phase feeding program

The objective of this study was to determine the standardized ileal digestible lysine (SID Lys) requirement of nursery pigs from 28 to 63 d of age fed a multi-phase feeding (PF) program and its possible adaptation to SID Lys-deficient diets. Ninety-six commercial hybrid piglets (Topigs Norsvin, 46 castrated males and 50 females) that had been weaned at 28 d of age with an initial body weight of 8.82 ± 0.28 kg were distributed in a randomized block design composed of four treatments, with eight replicates per treatment and three animals per replicate. The treatments were as follows: PF1, SID Lys levels of 1.05, 0.95, and 0.85%; PF 2, SID Lys levels of 1.15, 1.05, and 0.95%; PF 3, SID Lys levels of 1.25, 1.15, and 1.05%; and PF 4, SID Lys levels of 1.35, 1.25, and 1.15% from 28 to 35, 36 to 49, and 50 to 63 d of age, respectively. From 28 to 63 d of age, the average daily feed intake (ADFI) and average daily gain (ADG) were not affected by the SID Lys levels tested; however, final body weight (fBW) was affected, with PF1 having the lowest fBW. The SID Lys levels tested had a significant effect on the feed conversion ratio (FCR), which varied linearly from 28 to 35 d of age. In the period from 28 to 63 d of age, pigs fed PF4 had the highest FCR results. The protein deposition ratio (PDR) was also affected by the SID Lys levels tested, with PF3 and PF4 having the highest PDR results. Therefore, the optimal SID Lys requirement for nursery pigs from 28 to 35 d of age that provided better performance results was 1.25%, corresponding to a daily Lys intake of 4.13 g/d. PF3 provided the best performance and PDR results for piglets from 28 to 63 days of age.

Standardized ileal digestible lysine requirement of white commercial layers in peak egg production

This study was conducted to determine the standardized ileal digestible lysine (SID Lys) requirements for white commercial layers in peak egg production phase. A total of two hundred eighty-eight 24 week-old Hy-Line W-36 layers were randomly assigned to one of six treatments groups, with eight replicates of six hens each. A basal diet, SID Lys-deficient, was graded supplemented with L-Lysine HCl (78.4%) in order to produce experimental treatments (6.0, 6.6, 7.2, 7.8, 8.4 and 9.0 g SID Lys/kg diet). Throughout the 16-week-feeding trial (24 to 40 weeks of age) hens had free access to water and mash feed. Data were analyzed as one-way ANOVA and optimum SID Lys level for each dependent variable assessed were estimated using polynomial and linear broken-line regression model. Feed intake and SID Lys intake were both linearly enhanced by graded SID Lys levels. According to linear broken-line regression model, the breakpoint for egg production, egg weight, and egg mass occurred at 8.14, 8.56 and 8.35 g SID Lys/kg diet, respectively. The breakpoint for feed conversion per egg mass (kg/kg) and per dozen of eggs (kg/dozen) occurred at 8.48 and 7.80 g SID Lys/kg diet, respectively. Eggshell weight and albumen weight were unaffected by dietary SID Lys supply. Weight gain and yolk weight reached optimum values at 8.33 and 8.03 g SID Lys/kg diet, respectively, according to linear broken-line regression model. In conclusion, SID Lys requirement for white commercial layers in peak egg production phase is 8.48 g/kg diet, which corresponds to an average daily SID Lys intake of 813 mg/hen.

Digestible lysine requirements of male broilers from 1 to 42 days of age reassessed.

Three experiments were conducted separately to estimate the digestible Lys (dig. Lys) requirements of Cobb × Cobb 500 male broilers using different statistical models. For each experiment, 1,200 chicks were housed in 48 floor pens in a completely randomized design with 6 treatments and 8 replicates. Broilers were fed diets with increasing dig. Lys levels from 1 to 12 d (Exp. 1), from 12 to 28 d (Exp. 2), and 28 to 42 d (Exp. 3). Increasing dig. Lys levels were equally spaced from 0.97 to 1.37% in Exp. 1, 0.77 to 1.17% in Exp. 2, and 0.68 to 1.07% in Exp. 3. The lowest dig. Lys diets were not supplemented with L-Lysine and all other essential AA met or exceeded recommendations. In Exp. 3, six birds per pen were randomly selected from each replication to evaluate carcass and breast yields. Digestible Lys requirements were estimated by quadratic polynomial (QP), linear broken-line (LBL), quadratic broken-line (QBL), and exponential asymptotic (EA) models. Overall, dig. Lys requirements varied among response variables and statistical models. Increasing dietary dig. Lys had a positive effect on BW, carcass and breast yields. Levels of dig. Lys that optimized performance using QP, LBL, QBL, and EA models were 1.207, 1.036, 1.113, and 1.204% for BWG and 1.190, 1.027, 1.100, and 1.172% for FCR in Exp. 1; 1.019, 0.853, 0.944; 1.025% for BWG and 1.050, 0.879, 1.032, and 1.167% for FCR in Exp. 2; and 0.960, 0.835, 0.933, and 1.077% for BWG, 0.981, 0.857, 0.963, and 1.146% for FCR in Exp. 3. The QP, LBL, QBL, and EA also estimated dig. Lys requirements as 0.941, 0.846, 0.925, and 1.070% for breast meat yield in Exp. 3. In conclusion, Lys requirements vary greatly according to the statistical analysis utilized; therefore, the origin of requirement estimation must be taken into account in order to allow adequate comparisons between references.

Effect of feeding different levels of lysine and protein on the performance of WLH layers

A trial was conducted to evaluate the requirement of digestible lysine at various protein levels in the diet of WLH layers (BV-300) from 25-44 weeks of age. Layers (528) were fed with diets containing two protein levels i.e. 13.36 and 15.78 % each with 5 % concentration variations of lysine (0.50, 0.55, 0.60, 0.65, and 0.70) and a control with 17 % CP and 0.70 % lysine. Each diet was fed to six replicates of eight birds. Egg production, feed intake, body weight were not influenced either by the concentration of lysine or by level of protein in diet. Increased (P d” 0.05) egg weight and egg mass were observed with increasing lysine in diets. Better feed efficiency was observed with increasing lysine concentration. It can be concluded that WLH layers require approximately 0.65% lysine with 13.36% CP or 0.63% lysine with 15.78% CP (i.e. 598.80 vs 570 mg/h/day) in diet.

Estimation of the optimum digestible lysine level for Cherry Valley ducks

The aim of the current study was to determine the digestible lysine (DLys) requirement of Cherry Valley ducks from 1 to 14 d and from 15 to 35 d of age. One-day-old male Cherry Valley ducks (n = 320) were divided randomly and evenly into five treatments with 8 replicates of 8 birds. Ducks were fed adequate levels of digestible amino acid but with graded levels of DLys: 0.80, 0.88, 0.96, 1.04, and 1.12% from 1 to 14 d; 0.60, 0.68, 0.76, 0.84, and 0.92% from 15 to 35 d. At 35 d of age, 8 ducks per treatment were slaughtered for evaluating the yields of abdominal fat, subcutaneous fat, breast meat, and leg meat. Additionally, a 7-d metabolizable experiment was conducted with ducks of the same hatch beginning on d 35 (8 ducks per treatment). The results showed that the DLys level in diet had a quadratic relationship both with the average daily gain (ADG) and feed:gain ratio (F/G). According to the quadratic model, an optimum digestible lysine level was 0.948% from 0 to 14 d and 0.758% from 15 to 35 d based on ADG. The digestible lysine level for obtaining minimum F/G were 0.986% (0 ∼ 14 d) and 0.792% (15 ∼ 35 d), respectively. Breast meat yield (P = 0.110) and subcutaneous fat percentage (P = 0.021) showed a quadratic or linear response to the increasing dietary DLys level. To achieve maximum breast meat yield, the digestible lysine level of 0.961% and 0.761% were needed for the starter period (1 ∼ 14 d) and the growth period (14 ∼ 35 d), respectively. N excretion showed a quadratic response to the increasing dietary DLys level (P = 0.103). The results of the current study suggested that the optimum digestible lysine level was very different with the response criterion. The dietary digestible lysine levels were 0.948, 0.961% in the starter period (1 ∼ 14 d) and 0.758, 0.761% in the growth period (15 ∼ 35 d) for ADG, F/G, respectively.

273 Standardized ileal digestible lysine requirements for finishing PIC pigs under commercial conditions: A meta-analysis

273 Standardized ileal digestible lysine requirements for finishing PIC pigs under commercial conditions: A meta-analysis