Dietary Lys Levels Research Articles

PSII-12 Growth Performance of Pigs Fed Diets Containing Supplemental Lysine and a Low or High Essential Amino Acid-Nitrogen to Total Nitrogen Ratio

Abstract With the provision of low protein (LP) diets, it is possible that N, or non-essential amino acids (NEAA), become limiting. We have previously shown that the lysine (Lys) requirement for N retention is greater when pigs are fed a diet with sufficient N, as indicated by a low EAA-N:total N ratio (EAA-N:TN). The objective of this study was to investigate the effect of EAA-N:TN and Lys content on growth performance of growing pigs. A total of 240 growing pigs (20.6 ± 2.03 kg initial body weight) were randomly placed into groups of 5 pigs/pen (either 2 barrows and 3 gilts, or 3 barrows and 2 gilts) and randomly assigned to 1 of 4 dietary treatments (n = 12 pens/treatment) in 3 blocks in a 2 × 2 factorial design. Factors consisted of dietary EAA-N:TN [optimal ratio (LR) of 0.48 or high ratio (HR) of 0.55] and dietary Lys level of 1.03% SID or 1.22% SID, representing the NRC (2012) requirement and the requirement as determined previously, respectively. Diets were corn and soybean meal based and formulated to meet or exceed nutrient requirements according to NRC (2012). Pigs were individually weighed and feed intake determined weekly to determine average daily gain (ADG), average daily feed intake (ADFI), and gain:feed (G:F). Fecal samples were collected on d 14 for determination of N output. Data were analyzed using a mixed model with fixed effects of ratio, lysine, and their interaction and block as a random effect. Increasing dietary Lys resulted in increased overall ADG and ADFI, regardless of EAA-N:TN ratio (P < 0.01). Pigs fed the HR diets had improved ADG in week 4 (P < 0.05), whereas pigs fed the LR diets had improved ADG and G:F in week 1 (P < 0.01). There was an interactive effect of ratio and Lys on N output (P < 0.01), where N output decreased in the HR diets with 1.22% Lys. Overall, current Lys requirements may not be sufficient to maximize growth in 20-50 kg pigs, and greater Lys may be beneficial for reducing N output in LP diets.

Optimal dietary lysine improves the growth performance, molting frequency, lipid metabolism, immunity and antioxidant of postlarval mud crab Scylla paramamosain

A 56-day feeding trial was designed to investigate the effect of different dietary lysine (Lys) levels on the growth, molting, lipid metabolism, antioxidant, and immunity of postlarva Scylla paramosain. Six diets with 1.20%, 1.46%, 1.84%, 2.06%, 2.35%, and 2.67% Lys levels (dry matter) were formulated and experimented on the postlarva Scylla paramamosain. The results showed that Scylla paramamosain fed with the 2.06% lysine obtained the highest growth performance and the highest molting frequency. Appropriate dietary Lys levels (1.73–2.03%) can improve the antioxidant capacity of Scylla paramamosain. Although unaffected by dietary Lys, the whole-body lipid content of the 1.20% Lys group was numerically higher than those of the 1.46–2.67% Lys groups. The variation in whole-body crude protein content showed a similar trend with those in the content of EAA and NEAAs, with the highest whole-body crude protein content appearing in the 2.06% Lys group. The crabs obtained the highest expression of igf, fas, EcR and fabp genes in the 2.06% Lys group. When dietary Lys levels were > 1.20%, the transcription level of immune related-genes increased. As suggested by the results of the second order polynomial regression analysis of weight gain, the Lys requirement of postlarva Scylla paramamosain is 2.03% (4.51% of dietary protein).

Impacts of Dietary Lysine and Crude Protein on Performance, Hepatic and Renal Functions, Biochemical Parameters, and Histomorphology of Small Intestine, Liver, and Kidney in Broiler Chickens

The present study aimed to investigate the effects of increasing dietary lysine (Lys) levels with an adequate dietary crude protein (CP) content, as well as the effects of a reduction in dietary CP content with the recommended amino acid (AAs) level, on the performance, blood biochemical parameters, and histomorphology of the duodenum, liver, and kidney in broiler chickens. A total of 500 broiler chickens were randomly distributed into five dietary treatment groups, following a completely randomized design, where, at the beginning, the control group (C) was fed a diet containing the standard CP and Lys levels: 23% CP with 1.44% Lys during the starter period; 21.5% CP with 1.29% Lys during the growing period; and 19.5% CP with 1.16% Lys during the finishing period. The Lys content was increased by 10% above the recommended control basal requirements in the second group (Gr1) and by 20% in the third group (Gr2), while using the same recommended CP percentage as the C group. The fourth group (Gr3) had a 1% lower CP content and the fifth group had a 2% lower CP content than the C group, with the same recommended AA level as the C group. Increasing the Lys content in the Gr1 group improved the broilers' weight gains (p < 0.05) during the starter, growing, and finishing periods. Decreasing dietary CP with the standard AA levels (Gr3 and Gr4) did not significantly affect (p > 0.05) the live weight gain, feed intake, or feed conversion ratio (FCR) of the broilers compared with those fed with the C diet. Blood total bilirubin, direct and indirect bilirubin, triglycerides, cholesterol, low-density lipoprotein (LDL), and very LDL were not different among the experimental groups. However, blood aspartate aminotransferase levels were increased (p < 0.05) in the Gr1 and Gr3 groups compared with the other treatment groups. All dietary treatments decreased the serum creatinine levels (p < 0.05) compared with the C group. The Gr2 broilers had greater serum total protein and globulin (p < 0.05) than those receiving the other treatments. Increasing dietary Lys levels resulted in a significant improvement in duodenum villus height and width (p < 0.05), while the low-CP diets resulted in shorter villi length and width, along with degenerated areas and lymphocytic infiltration. Low dietary CP content induced hepatocyte disorganization and moderate degeneration, along with vacuolated hepatic cells, excessive connective tissue, and lymphocytic infiltration. The cortical regions of the kidney exhibited obvious alterations in the Gr3 and Gr4 groups and large interstitial spaces were found between tubules. Renal tubules in the Gr3 and Gr4 groups were smaller in size and some of these tubules were atrophied. In conclusion, reducing dietary CP levels to 1% or 2% lower than the recommended level did not negatively affect growth performance, inducing minimal influence on the blood metabolic indicators of health status, and resulting in moderate alterations to the histomorphology of the duodenum, liver, and kidney. Furthermore, increasing the Lys content by 10% above the recommended level improved the growth performance, health status, and histomorphology of the duodenum, liver, and kidney in broiler chickens.

Optimal dietary standardized ileal digestible lysine level for pigs during the grower, early and late finisher periods

BackgroundLysine (Lys) is the first limiting amino acid for pigs fed corn-soybean meal diets. Three experiments were conducted to estimate the optimal standardized ileal digestible (SID) Lys requirement for growing (Exp. 1), early finishing (Exp. 2), and late finishing (Exp. 3) pigs under commercial conditions.Results and conclusionsIn Exp. 1, a total of 650 growing pigs (32.21 ± 0.33 kg bodyweight), were allocated to 5 dietary treatments supplemented with 0.75, 0.85, 0.94, 1.03, and 1.13% SID Lys. Each treatment had 5 replicate pens with 26 pigs per pen. The lowest feed to gain ratio (F:G) was obtained by pigs fed the 1.03% Lys diet and F:G showed both a linear and a quadratic response with increasing Lys (P < 0.05). Based on broken-line and quadratic analysis models, dietary SID Lys levels for the minimum F:G were 0.94%. In Exp. 2, 650 finishing pigs (57.24 ± 2.00 kg bodyweight) were allotted to 5 dietary treatments providing SID Lys of 0.63, 0.71, 0.79, 0.87, and 0.95%. Each treatment had 5 replicates, 26 pigs per replication. The highest final bodyweight was achieved by 0.79% Lys while the highest average daily gain (ADG) and average daily feed intake (ADFI) was achieved by pigs consuming the 0.87% Lys diet (P < 0.05). Additionally, the lowest F:G was obtained by pigs fed the 0.79 and 0.87% Lys diet (P < 0.05). Based on broken-line and quadratic analysis models, the optimum Lys was 0.81 and 0.82% for ADG and F:G, respectively. In Exp. 3, 600 late finishing pigs (92.22 ± 2.41 kg bodyweight), were divided into 5 treatments providing Lys levels of 0.53, 0.60, 0.66, 0.73, and 0.79%. Each treatment had 5 replicates, 24 pigs per replication. Results showed that final bodyweight, ADG, ADFI, and F:G was not affected by increasing dietary Lys level, suggesting that the lowest SID Lys (0.53%) was sufficient for this group of pigs. Taken together, the SID Lys requirement for pigs from 30 to 60 kg, 60 to 90 kg, 90 to 120 kg was 0.94%, 0.81 to 0.82, and 0.53%, respectively, depending on the response criteria with performance maximized.

Effects of dietary lysine levels on growth performance, nutrient digestibility, serum metabolites, and carcase and meat quality of Yacha pigs

The objective was to evaluate the effect of different standardised ileal digestible lysine (SID-Lys) levels on performance, nutrient digestibility, serum metabolites, and carcase and meat traits of Yacha pigs. A total of 50 pigs were blocked by body weight and randomly assigned to five dietary treatments with six replicate pens (2 pigs/pen) per treatment using a randomised complete block design. Five diets in mash form were formulated to contain SID-Lys at 0.57%, 0.62%, 0.67%, 0.72%, 0.77% of diet in phase 1 (15 ∼ 30 kg), at 0.40%, 0.48%, 0.56%, 0.64%, 0.72% of diet in phase 2 (30 ∼ 50 kg), and at 0.30%, 0.39%, 0.48%, 0.57%, 0.66% of diet in phase 3 (50 ∼ 90 kg), respectively. The results showed that the average daily gain and gain to feed ratio increased with increasing dietary Lys levels in phases 1 and 2 (p ≤ 0.05). Increasing dietary Lys levels increased linearly (p ≤ 0.05) apparent total-tract digestibility of dry matter, gross energy, crude protein, and phosphorus in Phase 3 and also increased (p ≤ 0.05) concentration of serum glucose and tended to increase (p < 0.10) serum total protein in Phase 2. Compared with the Lys deficiently treatment, the adequate Lys treatment had increased carcase weight, lean meat percentage, and shear force and decreased cooking loss (p ≤ 0.05). Moreover, the optimal dietary SID-Lys levels preliminarily determined for 15 ∼ 30 kg, 30 ∼ 50 kg, and 50 ∼ 90 kg Yacha pigs were 0.760%, 0.628%, and 0.553% of the diet, respectively. HIGHLIGHTS Dietary appropriate SID-Lys levels can improve performance and feed utilisation in Yacha pigs. Dietary appropriate SID-Lys levels contributed to enhancing carcase lean meat yield of Yacha pigs.

Effects of Dietary Lysine Levels on Production Performance and Milk Composition of High-Producing Sows during Lactation.

Simple SummaryModern sows need increased nutrient levels to meet their lactation needs with a high litter size. Compared with multiparous sows, primiparous sows need to meet their lactation, growth, and developmental needs. Therefore, ensuring lactation nutrient intake for primiparous sows is important, and it increases the productivity of the entire breeding population. The objective of this experiment was to evaluate the effect of dietary lysine (Lys) levels for lactating primiparous sows on multiple reproductive cycles including piglet performance and milk composition. Results showed that increasing dietary Lys levels in lactation was beneficial for the survival rate of piglets, litter weight, piglet weight, and average daily gain (ADG) at weaning. The dry matter and protein concentrations in milk were increased by the increase in dietary Lys level. Therefore, when implementing strategies for improving reproductive efficiency, increasing the dietary Lys levels during lactation must be considered, especially for primiparous sows.Modern genotype sows require enhanced nutrition because of their larger body size and higher reproductive performance than 20 years ago. This study aimed to evaluate the effect of dietary Lys on the lactating of primiparous sows and the second lactating period to minimize sow body weight (BW) loss and maximize the survival rate of piglets and litter gain. A total of 160 primiparous Yorkshire sows were randomly allotted to one of four experimental lactation diets. Formulated to contain 0.84%, 0.94%, 1.04%, and 1.14% standardized ileal digestibility (SID) Lys and balanced in Met, Thr, Trp, and Val. No dietary effects were found on sow body weight (BW) and backfat thickness (BF) change and feed intake during lactation. However, the Lys intake (p = 0.04) of lactation increased linearly with increasing dietary Lys levels. In addition, 1.14% Lys for primiparous sow and 0.94% Lys for second parity sow during lactation increased the survival rate (p = 0.04), weight (p = 0.04), and ADG of piglets at d 21 (p = 0.03). The dietary Lys level did not affect colostrum compositions. However, the dry matter (p = 0.04) and protein (p = 0.03) in milk increased linearly with the increase in dietary Lys levels, whereas moisture decreased linearly (p = 0.05). The level of plasma urea nitrogen (PUN) also increased at d 21 of weaning (p = 0.04). These results indicate that high-yielding lactating sows required 1.14% SID Lys during parity 1, and 0.94% SID Lys during parity 2 to maximize the survival rate of piglets and litter gain, respectively. Moreover, the effects of dietary amino acid (AA) on the production performance of weaning pigs could be mediated through milk composition change.

Cobb MV × Cobb 700 broiler responses to eight varying levels of amino acid density with emphasis on digestible lysine

Summary The percentage of broiler complex processing plants slaughtering big birds (e.g., those greater than 3.5 kg) has steadily increased in the United States the past 15 yr. Precision amino acids in dietary formulation is key as the growing cycle for these birds is extended, as well as total feed consumed. Furthermore, broilers reared for big-bird slaughter plants are destined for specialty breast meat yield portioning, making digestible Lys one of the key nutrients in feed formulation. This work assesses dietary Lys levels in graduations across feed phases to 53 D in Cobb MV × Cobb 700 female and male broilers. Optimizing digestible Lys in the starter phase (to 14 D) occurred between 1.26 and 1.31%. On average, dietary Lys intake per bird needed to optimize live performance, and white meat yield was higher in male birds (64 g) than in female birds (58 g). Optimization of Lys amino acid density in the Cobb MV × Cobb 700 broilers resulted in increased white meat yields in larger broilers, resulting in increased fillet weights per bird with white striping and woody breast being unaffected.

Effects of dietary lysine on productivity, reproductive performance, protein and lipid metabolism-related gene expression in laying duck breeders

This study investigated whether dietary lysine (Lys) affects productive performance and expression of genes related to protein and lipid metabolism in laying duck breeders. Longyan duck breeders (n = 540, 19 wk of age) were randomly assigned to 6 groups with 6 replicates of 15 birds each. Breeders were fed diets with 6 total Lys levels (6.4, 7.2, 8.0, 8.8, 9.6, and 10.4g/kg) for 26 wk duration. Egg production, egg weight, egg mass, feed conversion ratio, hatchability, hatchling weight, albumen weight, eggshell weight, yolk weight, and yolk proportion increased with dietary Lys levels (P < 0.05). Dietary Lys level had a linear (P < 0.05) and quadratic (P < 0.05) effects on maternal hepatic expression of mechanistic target of rapamycin, eukaryotic translation initiation factor 4E binding protein 1, ubiquitin conjugating enzyme E2K (UBE2K), cathepsin B (CTSB), and quadratically (P < 0.05) increased the concentrations of plasma Lys, leucine, threonine, and tryptophan in duck breeders. In contrast, maternal dietary Lys suppressed expression of proteasome 26S subunit, UBE2K, and CTSB in the liver of hatchlings. Moreover, relative expression of peroxisome proliferator-activated receptors alpha, carnitine palmitoyltransferase 1A, and very low density apolipoprotein-II increased linearly (P < 0.05) and quadratically (P < 0.05), and that of VLDL receptor (VLDLR) decreased quadratically (P < 0.05) in the liver of duck breeders with increasing dietary Lys levels; hepatic triglyceride and cholesterol contents were reduced. Maternal dietary Lys suppressed hepatic expression of VLDLR in the hatchlings. A diet containing 8.6g Lys/kg promoted protein turnover and lipid metabolism in laying duck breeders, which positively reflected in the productivity and reproductive performance.

Effects of dietary surpluses of methionine and lysine on growth performance, blood serum parameters, immune responses, and carcass traits of broilers

ABSTRACT We evaluated the effects of dietary surpluses (100%, 110%, and 120% of Ross recommendations) of methionine (Met) and lysine (Lys) on growth performance, blood serum parameters, immune responses, and carcass traits of broilers using a completely randomized design with a 3 × 3 factorial arrangement. Broilers fed a diet containing Met and Lys according to Ross recommendations had maximal growth performance. During the starter period, higher Lys decreased intake of feed, energy, and protein (linear, P < 0.01) and weight gain (linear, P = 0.01). A diet with 110% Lys decreased feed efficiency (quadratic, P = 0.03) during the grower period and decreased the pre-slaughtered body weight (tendency; quadratic, P = 0.10), and increased serum uric acid (quadratic, P = 0.03). Dietary Lys level had an inverse correlation with serum phosphorus (linear, P = 0.02) and immune response against Newcastle disease virus after the first vaccination (linear, P = 0.03). There were Met × Lys interaction effects on serum glucose (P = 0.01), and relative weights of the rectum (P = 0.02) and liver (P = 0.02). Taken together, our results indicate that dietary surpluses of Met and Lys provided no additional benefits in broiler performance.

Effects of dietary lysine levels on growth, feed utilization and related gene expression of juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂)

An 8-week growth trial was undertaken to evaluate the effects of dietary lysine (Lys) levels on growth, feed utilization and related gene expression of juvenile hybrid grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂). Six isonitrogenous (53.5% of dry matter) and isolipidic (7% of dry matter) were formulated to contain 1.74%, 2.18%, 2.94%, 3.28%, 3.66% and 3.99% dietary Lys levels. Triplicate groups of 15 fish (average initial body weight: 11.44 ± 0.07 g) were fed each experimental diet to apparent satiation by hand twice daily (08:00 h and 16:30 h). Results showed that weight gain % (WG%) were significantly (P < .05) affected by different dietary Lys levels, and fish fed 1.74% dietary Lys had lower WG% than fish fed other dietary Lys levels. Daily feed intake (DFI) of fish fed 1.74% dietary Lys was higher than that of fish fed 2.18%, 2.94%, 3.28%, 3.66% or 3.99% dietary Lys. Feed efficiency (FE), protein efficiency ratio (PER) and protein productive value (PPV) showed similar variation trends as WG%. Hepatosomatic index (HSI) was reduced as dietary Lys levels increased. The protein contents in whole body, muscle as well as liver of fish fed 1.74% dietary Lys were lower than those of fish fed other dietary Lys levels. Fish fed 1.74% dietary Lys showed lower relative mRNA expression levels of insulin like growth factor-I (IGF-1), target of rapamycin (TOR) and S6 kinase 1 (S6K1) in liver than fish fed 2.18%, 2.94%, 3.28%, 3.66% and 3.99% dietary Lys. Based on the straight broken-line analysis of WG% against dietary Lys levels, the optimal dietary Lys requirement for hybrid grouper was estimated to be 2.16% of dry matter (corresponding to 4.05% of dietary protein on a dry weight basis).

Subsequent Effect of Dietary Lysine Regimens Fed in the Starter Phase on the Growth Performance, Carcass Traits and Meat Chemical Composition of Aseel Chicken in the Grower Phase

ABSTRACT This study was designed to examine carryover effect of dietary lysine (Lys) levels fed during the starter phase on the growth performance of three varieties of Aseel chickens. A total of 378 birds (126 from each variety) derived from a previous experiment, in which birds were distributed according a randomized block design in a 3×3 factorial arrangement, were evaluated from 7-18 weeks of age. Treatments consisted of three varieties of Aseel chicken [(Mianwali (MW), Peshawari (PW) and Lakha (LK)] fed three dietary Lys regimes (high, medium and low) during the starter phase (0-6 weeks). In the present experiment, the performance parameters, carcass traits, and meat chemical composition six replicates of seven birds per treatment were evaluated. The MW variety exhibited higher weight gain and better feed to gain ratio (p<0.05). Previous medium dietary Lys regimen improved weight gain, feed to gain ratio, final weight gain (p≤0.05). Birds previously fed medium dietary Lys showed higher thigh dry matter content (p<0.05), and those previously fed low Lys significantly higher thigh crude protein (CP) content (p<0.05). The highest breast muscle CP % were observed birds previously fed the high Lys regime (p<0.05), those of the MW variety (p<0.05). Higher slaughter weight and carcass weight and yield were obtained in the birds previously fed to medium dietary Lys level (p<0.05), and the MW variety showed overall better carcass traits (p<0.05). It is concluded that medium Lys levels in the starter feed promote subsequent better growth performance and that the MW variety has better carcass traits, it may be used as for rural chicken meat production.

Effects of dietary energy and lysine levels on growth performance and carcass yields of Pekin ducks from hatch to 21 days of age

A 2 × 6 factorial experiment, using 2 dietary apparent metabolizable energy (AME) levels (2,750 and 3,050 Kcal/kg) and 6 supplemental lysine (Lys) levels (0, 0.10, 0.20, 0.30, 0.40, and 0.50%), was conducted to study the effects of dietary energy and lysine levels on growth performance and carcass yields of Pekin ducks from hatch to 21 d of age. A total of 576 one-day-old male White Pekin ducks was randomly allotted to 12 dietary treatments, each containing 6 replicate pens with 8 birds per pen. At 21 d of age, body weight gain, feed intake, and feed/gain were measured, and then 2 ducks selected randomly from each pen were slaughtered to evaluate the yields of abdominal fat, breast meat, and leg meat. As a result, birds that were fed basal diets with no Lys supplementation showed growth depression, and significant positive effects of dietary Lys supplementation on body weight gain (P < 0.001), feed intake (P < 0.001), and feed/gain (P = 0.002) were observed as dietary Lys increased gradually among all the groups. In addition, increasing energy levels did not affect overall body weight gain (P > 0.05), but feed intake (P = 0.001) and feed/gain (P = 0.009) decreased significantly between the groups. Dietary Lys levels influenced the yields of breast (P < 0.001) and leg (P = 0.001) meat among all the groups, but dietary energy levels had a significant positive effect only on abdominal fat yield (P = 0.014). The interaction between dietary energy and Lys influenced body weight gain of ducks significantly (P = 0.004). According to the broken-line regression analysis, Lys requirements of Pekin ducks for weight gain at 2,750 and 3,050 Kcal of AME/kg were 0.94 and 0.98%, respectively. It suggested that Lys requirement was higher at 3,050 Kcal of AME/kg than at 2,750 Kcal of AME/kg. Dietary energy content determined feed intake of the ducks, and high-energy diets will require a higher amino acid concentration to compensate for a lower feed intake.

Effects of lysine and tryptophan supplementations in plant protein-based diets on the performance of Nile tilapia (Oreochromis niloticus)

ABSTRACTIn this experiment, six soybean-based diets were formulated to be isonitrogenous and isoenergetic on a digestible basis. The treatments consisted of two levels of lysine (Lys) (0.25%, 0.5%) with three levels of tryptophan (Try) (0.05%, 0.1%, and 0.2%): D0.25°.05, D0.25°.1, D0.25°.2, D0.5°.05, D0.5°.1, and D0.5°.2 (Diets 1–6), where the subscripts and superscripts refer to the levels of Lys and Try, respectively. A total of 270 Nile tilapia (Oreochromis niloticus; initial body weight: 4.43g ± 0.01 g) were randomly assigned to 18 tanks with 15 fish per tank, three replicate tanks per treatment. After an 8-week growth period, the results showed that the interaction between dietary Lys and Try levels and the main effect of dietary Lys levels were not significant on the final body weight (FBW), while dietary Try levels significantly affected FBW (P < 0.05). Fish fed Try°.2 diets had significantly higher final body weight (FBW) compared with all the other dietary treatments, while fish fed Try°.05 had the lowest FBW. Furthermore, no significant differences were observed among dietary treatments for proximate whole body composition. The results of this study indicate that Try can be supplemented at a level up to 0.2% in Nile tilapia diets containing high levels of soybean meal (44%) to maximize the growth of fingerlings.

Assessing Lysine Requirement of Growing Chicken by Direct Comparison between Supplementation Technique and “Goettingen Approach”

Validated procedures play an important role to obtain accurate information about individual amino acid requirement data. The aim of the present study was to assess lysine (Lys) requirement of growing chicken both by classical supplementation technique and principles of diet dilution technique as applied with “Goettingen approach”. During the starter period (1 - 21 d), a growth study with male meat type chicken (Ross 308) was conducted making use of five graded dietary Lys-levels (3 repetition boxes with 3 birds/box). L-Lys×HCl was gradually added to a diet based on wheat, soybean protein concentrate, wheat gluten and fishmeal to yield 80%, 87.5%, 95%, 102.5% and 110% of the expected requirement level (13 g Lys/kg as fed). Diets were iso-energetic (12.8 MJME/kg) and iso-nitrogenous (21.65% crude protein). Birds were fed on free choice level also to assess the feed intake (FI) effects as important factor on traditional response criteria. Analyzed body composition at start and end of the growth study yielded N deposition (ND) data for further data assessment using exponential approximations depending on dietary Lys content or observed Lys intake. The results indicated significant differences (p (BWG, ND) taking also into account the expected real feed intake to formulate the needed in-feed concentration.

Effects of protein intake on rate of growth, protein deposition, and carcass traits of heavy Iberian pigs.

A feeding, digestibility, and balance trial was performed to determine the effect of the incorporation of increasing amounts of soybean protein concentrate (SPC) to a basal acorn diet at a fixed energy intake on the rate of growth, protein deposition (PD), and carcass traits of heavy Iberian (IB) pigs. Sixteen purebred IB barrows (103.9 ± 0.9 kg initial BW) were used. The pigs were individually confined and allocated to 4 groups of 4 pigs each. Whole acorns were provided with slight restriction to minimize acorn kernel (AK) remains. Water was freely available. The incorporation of SPC raised the available CP from 49.1 g/kg DM (1.91 g total Lys/kg DM) in AK up to 135 g/kg DM (7.24 g total Lys/kg DM). After 72 d of trial, the pigs achieved 134.4 ± 1.3 kg BW and were then slaughtered. Average daily BW gain increased with increasing dietary CP (linear, P < 0.001; quadratic, P < 0.01), with a plateau at dietary CP concentrations (provided by AK and SPC) beyond 72.2 and 100 g/kg DM, respectively, for which an ADG of 449 g was achieved. There was a linear and quadratic effect of dietary CP and Lys level on the apparent digestibility of CP (linear, P < 0.001; quadratic, P < 0.05) and on the efficiencies of utilization of total N (retained N/N intake; linear, P < 0.001; quadratic, P < 0.001) and N apparently absorbed (retained N/apparent digestible N; linear, P < 0.05; quadratic, P = 0.067). Protein deposition ranged between −4.59 g/d in pigs not provided with SPC to 61.4 g/d in pigs fed the greatest level of SPC inclusion. The lowest daily intake of total Lys resulting in maximum PD (69.5 g/d) at the fixed level of energy intake observed (2.36 × ME maintenance requirements) was 21.0 g. Hot carcass and cold carcass weights, but not carcass yield, increased when feeding the daily ration containing 100 g SPC and leveled off thereafter (linear, P < 0.01; quadratic, P < 0.01). An average increase of 8.3% and 8.7% was obtained, respectively. The provision of SPC had no effect on back fat thickness. Primal cuts, but not yield (except for loin), increased (sirloin: linear, P < 0.05; loin: linear, P < 0.001; quadratic, P < 0.05; ham: linear, P < 0.05) or showed a tendency to increase (butt lean: linear, P = 0.068; quadratic, P = 0.077; ribs: quadratic, P = 0.067; shoulder: quadratic, P = 0.064) with the provision of dietary protein. No effect of the level of incorporation of SPC to the diet was observed on CP, total fat, total ash, and energy contents or on relative fatty acid profile of loin and sirloin.

The effects of previous dietary Lys concentration on subsequent growth performance of two different pig genotypes

The aims of this study were to determine whether Lys restriction immediately after weaning could be compensated for when pigs were switched to a high-Lys diet, and to determine whether this may be influenced by genotype. The experiment was a 2×2 factorial arrangement of diets and genotypes with 8 replicate pens per treatment and 8 or 9 mixed sex pigs per pen. Pigs received either a high- (Control; 17.5g/kg of Lys) or a low-Lys (WR; 8.0g/kg of Lys) diet during the first 3 week post-weaning followed by a high-Lys diet (15.5 and 12.0g/kg of Lys during the grower and finisher phases, respectively) to facilitate compensation until slaughter (approximately 101.2 ± 4.9kg). Two hundred and sixty four pigs [132 Hampshire sire×(Large White×Landrace) dam and 132 Large White sire×(Large White× Landrace) dam] were used and are referred to as Hampshire pigs and Large White pigs. Blood samples were collected from 2 selected pigs per pen at 6, 9, and, 15 week of age for blood urea nitrogen (BUN), non-esterified fatty acids (NEFA), and leptin analysis. Throughout the weaner phase, Control pigs gained more (105±1g/d) than WR pigs (P<0.001). However, once pigs were switched to a high-Lys diet, WR pigs gained more (44±9kg/d) than Control pigs and utilised their feed more efficiently (P<0.001), and thus compensatory growth was observed. Pigs of both genotypes performed similarly throughout the weaner stage when fed the low-Lys diet, however, when fed the high-Lys diet, Hampshire pigs had a greater rate of gain compared to Large White pigs (308 vs. 296±8g/d). Throughout the experiment, Hampshire pigs ate more feed (P<0.001), gained more (P<0.001), and had a greater Lys intake (P<0.001) compared to Large White pigs. Lean meat percentage at slaughter was greater for the Large White pigs compared to Hampshire pigs (P<0.05). At 6 week of age NEFA concentrations were greater for Control pigs compared to WR pigs (P<0.05). Hampshire pigs on the WR treatment had lower BUN levels during the weaner period compared to Hampshire pigs on the Control treatment (P<0.10). In conclusion compensatory growth was observed in both genotypes. The fact that Hampshire pigs grew faster when fed a non-limiting diet but grew at a similar rate compared to Large White pigs when fed a limiting Lys diet indicates that limiting dietary Lys level rather than genotype determined growth performance.

Estimation of the standardized ileal digestible lysine requirement and the ideal ratio of threonine to lysine for late finishing gilts fed low crude protein diets supplemented with crystalline amino acids

Two experiments were conducted to investigate the effects of various standard ileal digestible (SID) lysine (Lys) levels and SID threonine (Thr) to Lys ratios on the performance and carcass characteristics of finishing gilts receiving low crude protein (CP) diets supplemented with crystalline amino acids (CAA). In Exp. 1, 108 gilts (87.8±5.9kg) were randomly allotted to one of six diets which consisted of a high CP (135g/kg) diet with 6.1g/kg SID Lys or five low CP (100g/kg) diets providing SID Lys levels of 4.9, 5.5, 6.1, 6.7 and 7.3g/kg, respectively. Gilts were housed in three pigs per pen with six pens per treatment. At the end of the 28 days experiment, 36 gilts (one pig per pen) with average body weight (BW) of 116kg were killed to evaluate carcass traits. The SID Lys levels required to maximize average daily gain (ADG) and optimize feed conversion ratio (FCR) as well as to minimize serum urea nitrogen (SUN) levels were 5.7, 5.8 and 6.1g/kg using a linear-break point model and 6.5, 6.5 and 6.6g/kg using a quadratic model. The fat-free lean gain tended to increase linearly with the increase in dietary SID Lys levels from 4.9 to 7.3g/kg when gilts receiving a low CP diet (linear effect, P=0.06). In Exp. 2, 90 gilts (90.6±5.7kg) were utilized in another dose–response study. Based on the Lys requirement estimated in Exp. 1, dietary treatments were formulated to contain 5.1g/kg SID Lys to ensure the dietary Lys level was marginally deficient for late finishing gilts. Graded levels of crystalline Thr (0, 0.3, 0.6, 0.9 or 1.2g/kg) were added to the basal diet providing SID Thr to Lys ratios of 0.54, 0.60, 0.66, 0.72 or 0.78, respectively. Each diet was fed to six pens with three gilts per pen. At the end of Exp. 2, 30 gilts (one pig per pen) were slaughtered to evaluate carcass traits (average BW=118kg). The optimum SID Thr to Lys ratios to maximize ADG and FCR as well as to minimize SUN levels were 0.61, 0.63 and 0.64 using a linear-break point model and 0.70, 0.75 and 0.74 using a quadratic model. With the exception of L* light (linear effect, P<0.05), no effect on carcass characteristics was observed with increasing dietary SID Thr to Lys ratio.

Effect of increasing lysine supply during last third of gestation on reproductive performance of Iberian sows

Ninety purebred Iberian (IB) sows in second or third parity were used to determine the effects of dietary lysine (Lys) concentration during last third of pregnancy on sow and litter performance. The sows were randomly assigned to one of three dietary treatments: 5.5 (LLys, Control), 7.4 (MLys) and 8.7 (HLys) g Lys kg-1 diet. Feed allowance was 2.30-2.33 kg d-1. Close to farrowing a conventional lactation diet was used. Dietary Lys did not affect body-weight (BW) gain in late gestation of second-parity sows. However, in third-parity sows, a strong tendency was observed for BW gain to increase during late pregnancy with dietary Lys levels higher than 5.5 g kg-1 (p=0.061). Body-weight losses during lactation were never influenced by Lys supply. A strong tendency (p=0.064) for a lower ratio between piglets born alive and total piglets born was observed in second-parity sows fed the Control gestation diet. Litters and piglets from sows on this diet had the lowest weight at birth (p0.05). In conclusion, under moderate energy supply, adequate reserves for subsequent lactation can be achieved in second- and third-parity IB sows with a daily provision of at least 17.2 g lysine over the last third of pregnancy, what implies a substantial increase in protein supply respect to traditional practices.

Estimation of dietary lysine requirement based on broken line and quadratic model analyses with the use performance and immune responses criterion

The aim of this study was to determine the effects of supplementing Lysine (Lys) at on growth performance and immune responses of broiler chickens challenged with infectious bursal disease (IBD) and estimation of Lys requirement based on different response criterions. A total of 400-day-old male broiler chicks were assigned to eight dietary treatments. Chickens were fed by eight graded levels of Lys (0.8 National Research Council (NRC) (0.75% of diet), 0.9 NRC (0.85% of diet), NRC (0.94 of diet), 1.1 NRC (1.03% of diet), 1.2 NRC (1.13% of diet), 1.3 NRC (1.22% of diet), 1.5 NRC (1.41% of diet) and 1.8 NRC (1.69% of diet)) from day 21 to 42 of age. On day 28, all birds were challenged with a commercial live-IBDV vaccine. Body weight gains (BWG), feed conversion ratio (FCR) and carcass characterization (breast, thigh and fat pad percentage) were significantly influenced by dietary Lys levels. With increasing Lys level up to 1.22% of diet, performance improved significantly and with higher than this level decreased. Antibody titre against IBD was influenced by Lys levels. On 7 and 14 days after IBD challenge, antibody titre against IBD of broilers that receive diet that contain Lys higher than NRC recommendation wwas significantly higher than those receive lower level and the highest antibody level found in 1.22% Lys in diet. The highest (1.2519±0.0441) and the lowest (1.0408±0.11) Lys requirements with straightbroken line analysis were estimated for immune response and carcass efficiency percentage, respectively. The results obtained on the present study indicated that Lys requirements of broiler based on recommendation of NRC are not sufficient to meet the requirement of the new commercial poultry and commercial broiler companies under non-hygienic condition.

The interactive effects of glycine, total sulfur amino acids, and lysine supplementation to corn-soybean meal diets on growth performance and serum uric acid and urea concentrations in broilers

Four experiments were conducted to determine the interactive effects of Gly, TSAA, and Lys in corn-soybean meal diets on growth performance of broilers. All experiments were conducted with female Ross x Ross 308 or 708 broilers in brooder batteries from 0 to 18 d posthatching. Treatments had 5 to 8 replications with 5 or 6 broilers per replicate pen. Diets in all experiments were fed without or with Gly (2.32% total Gly + Ser). All diets contained 0.25% l-Lys.HCl except in experiment 1, where no crystalline Lys was added. In experiment 1, the total dietary Lys level was 1.26% with TSAA:Lys of 0.72 and 0.76. Increasing TSAA:Lys increased (P < 0.07) G:F. The main effect of Gly was not significant for ADG, ADFI, or G:F; however, G:F was increased by Gly in broilers fed 0.72 but not in those fed 0.76 TSAA:Lys (Gly x TSAA:Lys, P < 0.03). In experiment 2, the total dietary Lys level was 1.26% with TSAA:Lys of 0.51, 0.68, 0.72, and 0.76. Glycine addition did not affect ADG, ADFI, or G:F; however, increasing TSAA:Lys linearly increased (P < 0.01) ADG, ADFI, and G:F and the response was quadratic for ADG and G:F. Experiment 3 was similar to experiment 2 except the total dietary Lys level was 1.35%. Glycine addition increased (P < 0.03) G:F and decreased (P < 0.04) serum uric acid (SUA) and serum urea N concentrations. Also, increasing TSAA:Lys linearly and quadratically (P < 0.02) increased ADG, ADFI, and G:F. In experiment 4, broilers were fed 2 levels of total dietary Lys (1.26 and 1.35%), 3 levels of TSAA:Lys (0.72, 0.76, and 0.80), and without or with Gly supplementation up to a total of 2.32% Gly + Ser. Glycine addition increased ADG (P < 0.02) and G:F (P < 0.01). The increase in G:F with Gly was not the same for all TSAA:Lys (Gly x TSAA:Lys, P < 0.07). Increasing Lys increased (P < 0.01 to 0.10) ADG, ADFI, and G:F. Glycine addition increased ADG and ADFI more in broilers fed 1.35% Lys than in those fed 1.26% Lys (Lys x Gly, P < 0.09). Glycine addition increased SUA in broilers fed 1.26% Lys but decreased SUA in broilers fed 1.35% Lys (P < 0.01). Glycine addition decreased SUA in broilers fed the TSAA:Lys of 0.80 but not at the other TSAA:Lys (P < 0.08). These data indicate that Gly increased G:F and decreased SUA in diets with 1.35% Lys and excess TSAA.