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Deals with a study which evaluated the effect of milk replacers utilizing liquid egg as an alternative protein on the performance of dairy calves. Materials and methods; Results; Discussion; Conclusions.

An experiment was conducted with 351 sows (PIC Camborough) to evaluate the effects of SID lysine intake on sow and litter performance during a 23-d lactation period. Sows were randomly allotted within parity block (parity 1, parity 2, and parity 3+) to one of five corn soybean meal based lactation diets formulated to contain different levels of SID lysine (49, 57, 65, 73, and 81 g/d, respectively). All diets were formulated to be isocaloric (3.3 ME Mcal/kg) and contained vitamins and minerals that exceeded recommendations (NRC, 2012). Experimental diets were given to sows from 112 d of pregnancy throughout the 23-d lactation period. Litters were standardized within 48 h after farrowing, and sows were allowed 5.9 kg of feed/d throughout the lactation period. Sows were fed with a computerized feeding system to record daily sow feed intake during lactation. Data were analyzed as a randomized complete block design using the PROC MIXED procedure of SAS with sow as the experimental unit and treatment as a fixed effect and parity as the random effect. Results were considered significant at P ≤ 0.05 and considered a trend at P > 0.05 and P ≤ 0.10. There were approximately 70 replications per treatment. Sow ADFI was lower (P >0.10) than calculated (5.14, 5.05, 5.20, 5.19, 5.15 kg/d) resulting in a SID Lys daily intake of 42.8, 48.9, 57.4, 64.5, 71.1, respectively. Increasing dietary lysine intake resulted in a significant linear increase (2.04, 2.42, 2.80, 3.16, 3.47; P < 0.05) in litter average daily gain as dietary lysine increased. There were no differences in wean to estrus interval, sow weight loss, or subsequent total born across the dietary treatments. Overall, increasing levels of SID lysine resulted in a linear increase in litter average daily gain during lactation with no major influence in the other parameters. The lower than expected lactation intake could have caused energy to be a limiting factor in this study. [ABSTRACT FROM AUTHOR]

Camborough PIC sows (n = 255) were fed either increasing lysine levels or feeding amounts to determine the influence on piglet birth weight. Gestating sows (56 sows per pen) were fed with electronic sow feeding stations and had a body condition score of 3.00-3.25 on a 1-5 scale. One diet per pen was fed to minimize diet crossover. Litters were weighed within 16 h of birth. Sows were weighed at the initiation of the study, d 112 of gestation. Post-farrowing weight was calculated using a B W equation based on d 112 gestation weight. Data were analyzed using a randomized complete block design and treatment as the fixed effect, as well as, pairwise contrasts. In study one, females were fed 1 of 2 treatments (Control-1.8 kg/d of feed (9 g SID lysine/d intake) or Bump- Control diet fed at 2.7 kg/d (14 g SID lysine/d)). P2 females were housed separately and were fed either Control (24 sows) or Bump (17 sows) diets for 2 wk due to pen allowance. P3+ females were fed diets for a period of 3 wk (40 Control and 45 Bump sows). For P3+ sows fed the Bump, 48-hr post farrow BW was higher (P = 0.02). Average piglet weight was not different (1.28 vs. 1.31 kg; P > 0.10). For the P2 females, average piglet weight (P > 0.10) and 48 hpost-farrow body weight (181.8 vs. 189.7 kg; P > 0.10) was not different between treatments. Since there was no effect on bump feeding sows, primiparous females were fed 1 of 3 diets (Control- 1.8 kg/d (9 g SID lysine/d, 53 gilts); Bump- control diet fed at 2.7 kg/d (14 g SID lysine/d, 30 gilts); or High- 1.8 kg/d (13.5 g SID lysine/d, 46 gilts)) for 3 wk pre-farrow to determine the impact of different feeding programs on gilt litter performance in study 2. The Bump had lighter piglets at birth compared to the Control (1.12 vs. 1.24 kg; P = 0.04). However, this was likely due to the higher total born, which was not attributed to treatment (14.07 vs. 12.66 pigs). The High did not produce heavier piglets compared to the Control (1.28 vs. 1.24; P > 0.10) or reduce the percentage of < 0.90 kg pigs (10.11 vs. 11.32%; P > 0.10). Feeding increased Lys levels or additional feed to gestating animals in good body condition did not result in improved piglet birth weight. [ABSTRACT FROM AUTHOR]

A study was conducted to test the effects of liquid L-Lys supplementation on growth performance in growing-finishing pigs compared with crystalline L-Lys HC1. A total of 126 pigs at 70 d of age (29.5 kg B W) in 42 pens were randomly allotted to 7 dietary treatments which were, CON: a control diet without supplemental Lys meeting 75% of SID Lys requirement, Level 1 diets with crystalline L-Lys HC1 (CI) or liquid L-Lys (LI) meeting 82% of SID Lys requirement, Level 2 (C2 or L2) diets meeting 89% of SID-Lys requirement and Level 3 (C3 or L3) diets meeting 96% of SID Lys requirement. Each treatment had 6 pens (3 barrow and 3 gilt pens) with 3 pigs/ pen. All 7 diets were formulated to contain nutrients meeting the requirements suggested by NRC (2012) except for SID Lys. Pigs were fed experimental diets for 9 wk based on 3 phases until 90 kg BW (30 to 45, 45 to 75, and 75 to 90 kg BW, respectively). All experimental diets were pelleted. Body weight and feed disappearance were measured to calculate ADG, ADFI, and G:F. Data were analyzed using the MIXED procedure in SAS. A mutilinear regression analysis was used to evaluate the relative bioavailability of liquid L-Lys to crystalline L-Lys HC1. Increasing Lys from 75 to 96% of SID Lys requirement improved (P < 0.05) ADG from 0.83 to 1.00 kg/d and G:F from 0.384 to 0.430 without affecting ADFI. Forms of Lys (crystalline vs. liquid) did not affect performance of pigs. Rates of increases in ADG and G:F of pigs fed diets with liquid L-Lys was not different (P = 0.803 and 0.336) from that of pigs (39.4 vs. 37.0 g/g daily intake of supplemental Met and 0.00828 vs. 0.00696/g daily intake of supplemental Met) fed diets with crystalline L-Lys HC1. This study demonstrates that efficacy of liquid L-Lys is not different from that of crystalline L-Lys HC1 for performance of pigs from 30 to 90 kg. [ABSTRACT FROM AUTHOR]

Lysine is the first limiting amino acid in practical swine diets, so it is important to optimize the dietary digestible lysine to maximize growth and profitability. Two experiments were conducted to estimate the standardized ileal digestible (SID) Lys requirement for pigs from 25- to 50-kg BW (Exp. 1) and 50- to 75-kg BW (Exp. 2) using ADG and G:F as criteria responses. A total of 1050 barrows and gilts (FAST Fl female x PIC380 boar line) were used in each experiment, blocked by gender, with 10 pens per treatment and 21 pigs per pen. Experimental diets were formulated to contain 2.3 Meal NE/ kg and to meet or exceed all nutrient requirements except Lys, according to NRC (2012). Minimum ratios of 30% Met:Lys, 60% Met+Cys:Lys, 21% Trp:Lys, 70% VakLys, 55% Ile:Lys, and 102% Leu:Lys on a SID basis were used for all diets. The SID ThnLys ratio was 65 and 66% for Exp. 1 and 2, respectively. In Exp. 1, pigs were fed diets formulated to contain 0.72, 0.80, 0.88, 0.96 or 1.04% SID Lys whereas in Exp. 2 diets were formulated to contain 0.68,0.75, 0.82,0.89 or 0.96% SID Lys. Responses measured at the pen level were analyzed using general linear and nonlinear heteroskedastic mixed models. Dose response curves were evaluated using linear (LM), quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic (BLQ) models. For each response variable, the best-fitting model was selected using Bayesian information criterion. Gender was used as covariate when significant. Increasing SID Lys content in the diet quadratically (P < 0.01) increased ADG and G:F in Exp. 1 and linearly (P < 0.001) increased ADG and G:F in Exp. 2. From 25- to 50-kg, the best-fitting models for ADG and G:F were the LM and QP, respectively, with the maximum response estimated at > 1.04% SID Lys. From 50- to 75- kg BW, the best-fitting model for ADG was the BLQ estimating the requirement at 0.83% (95% confidence interval [CI]: [0.80%, 0.86%]) SID Lys, with 99% of maximum achieved with 0.82%. For G:F, the BLL was the best-fitting model and the SID Lys requirement estimated at 0.85% (95% CI: [0.75%, 0.94%]) with 99% of maximum achieved with 0.80%. In conclusion, the SID Lys requirement for 25- to 75-kg pigs may be higher than the recommendation from NRC (2012). [ABSTRACT FROM AUTHOR]

Barrows and gilts (PIC 29 x 380, n = 147) were blocked by initial BW (6.42 ± 1.21 kg) at weaning (21 ± 3 d) and allotted to pens (7 pigs/pen) within each of 7 blocks to evaluate the effects of aggressive feed-grade AA supplementation with reduced CP (RCP) diets formulated on either a ME or NE basis on growth performance of nursery pigs. Pens within blocks were randomly assigned to 1 of 3 treatments: 1) corn-SBM-corn DDGS-based diets formulated to meet the Tip requirement without addition of feed-grade Trp (feed-grade Trp was added in phase 3 to increase the Trp:Lys ratio from 17 to 19; Ctrl); 2) RCP diets formulated to meet the His:Lys ratio requirement (His:Lys = 32) without added feed-grade His and formulated on a ME basis (RCP-ME); or 3) RCP diets to meet the His:Lys requirement without feed-grade His and formulated on a NE basis (RCP-NE). Feed-grade AA were added to diets to meet all SID AA:Lys ratio requirements (M+C:Lys, 58; Thr:Lys, 60; Trp:Lys, 17 in phase 1 and 2 and 19 in phase 3; Ile:Lys, 55; Val:Lys, 65 in phase 1 and 2 and 70 in phase 3; His:Lys, 32) during each phase. During phases 1 and 2, feed-grade AA in RCP diets completely replaced poultry byproduct and partially replaced SBM in Ctrl diets. In phase 3, feed-grade AAs were included at the expense of SBM. Poultry fat was reduced inNE compared to ME-based diets. Neither ADG, ADFI, G:F, nor BW at the end of phases 1 and 2, as well as the end of the study, were affected (P > 0.40) by high inclusion levels of feed-grade AA in either ME- or NE-formulated diets. These results indicate that similar performance can be achieved with either ME-or NE-based nursery diets formulated to meet the His:Lys ratio without adding feed-grade His when supplemented with high levels of essential feed-grade amino acids to meet the AA:Lys ratios. [ABSTRACT FROM AUTHOR]

Previous research indicates aggressive feeding of AAto growing/finishing pigs results in reduced intake, gain, and fatter carcasses. This study investigated the role of dietary essential AA, nonessential AA, and electrolyte balance on these outcomes. PIC C29 x 380 pigs (n = 196) were blocked by BW and treatments assigned to gender-balanced pens within block. Treatments were: 1) corn-soybean meal diets formulated to meet a constant Trp:Lys ratio (20) without feed grade Trp (PC); 2) RCP diets meeting the His:Lys ratio requirement (32) without added feed grade His but with feed grade indispensable AA added to control levels (Met+Cys:Lys, 60 to 65; ThnLys, 65 to 68; Trp:Lys, 20; Ile:Lys, 73 to 78; Val:Lys, 79 to 88; His:Lys, 45 to 51; EAA); 3) as 2 but with feed grade Glu and Gly (67:33) added to the same N in PC (NEAA), or 4) as 3 but with diets formulated using NaHCO3 to create the same dietary electrolyte balance as PC (dEB). All diets met the SID AA:Lys ratio requirement for each phase (23 to 41, 41 to 59, 59 to 82, 82 to 104, and 104 to 131 kg BW). Rac-topamine (10 mg/kg) was fed during the last 3 wk. Pig BW and pen feed disappearance data were used to calculate ADG, ADFI, and G:F for each pen. HCW, LM and fat-depth (10th rib) were captured by Fat-O-Meter at slaughter. Pig growth performance and carcass composition were maintained by adding feed grade EAA to the RCP diet. ADG, ADFI, G:F and carcass characteristics did not respond to NEAA or NaHCO3 additions. These results suggest the reduced performance of growing/finishing pigs fed RCP diets formulated to meet the His:Lys requirement without using feed grade His in previous studies may be attributed to improper AA:Lys ratios and not from total N or dietary electrolyte balance. [ABSTRACT FROM AUTHOR]

A total of 280 pigs (PIC 327 x 1050; initially 6.53 kg BW) were used in a 28-d trial to evaluate the effects of increasing standardized ileal digestible (SID) Val:Lys ratio on nursery pig growth performance. Pigs were weaned at 21 d of age and 5 pigs allotted to each nursery pen according to BW and gender. A common diet was fed for 5 d when pens were assigned to 1 of 7 dietary treatments in a randomized block design with 8 pens per treatment. Experimental diets were fed from d 0 to 14 followed by a common diet from d 14 to 28. The 7 dietary treatments were 50, 57, 63, 68, 73, 78, and 85% SID Val:Lys. A prior experiment demonstrated a Lys requirement of 1.44 and 1.45% SID Lys for ADG and G:F, respectively, for pigs in this facility. Thus, diets were formulated to 1.24% SID Lys to ensure pigs were below the Lys requirement. As SID ValLys increased, ADG, ADFI, and G:F increased (quadratic, P < 0.05). Growth response variables were fitted using linear and nonlinear dose-response models with pen as the experimental unit and initial BW as a covariate with ADG and G:F fitted using heterogeneous and homogenous residual variance, respectively. Models fit were quadratic polynomial (QP), broken-line linear (BLL), and broken-line quadratic with best fit determined according to Bayesian information criterion. For ADG, the best fitting model was BLL and maximum ADG was achieved with a minimum of 62.9% SID ValLys (95% CI: [52.2, 73.7%]). For G:F, the best fitting model was QP [0.010294 + 0.017526*(Val:Lys)- 0.000122*(Val:Lys)2] using a 6.53-kg initial BW. This resulted in a maximum G:F at 71.7% SID ValLys and 99% of maximum achieved at a 64.4% ratio. In summary, the SID ValLys requirement ranged from 62.9 to 71.7% depending on the response model. [ABSTRACT FROM AUTHOR]

Two experiments were conducted to estimate the standardized ileal digestible (SID) Val:Lys requirement for growth performance in 25- to 45-kg pigs. In Exp. 1, 1134 gilts (PIC 337), initially 31.2 kg (SD 2.0) BW, were used in a 19-d trial with 27 pigs/pen and 7 pens/treatment. In Exp. 2, 2100 gilts (PIC 327), initially 25.4 ± 1.9 kg BW, were used in a 22-d trial with 25 pigs/pen and 12 pens/treatment. In both experiments, treatments were blocked by initial BW in a randomized complete block design. In Exp. 1, there were 6 treatments with SID Val:Lys at 59.0, 62.5, 65.9, 69.6, 73.0, and 75.5%. For Exp. 2, there were 7 treatments with SID Val:Lys at 57.0,60.6, 63.9, 67.5, 71.1, 74.4, and 78.0%. Diets were formulated to ensure that Lys was the second limiting AA throughout the experiments. Responses were analyzed separately for each experiment using general linear and nonlinear heteroskedastic mixed models, including initial BW as an explanatory covari-ate and B W block as a random effect. In Exp. 1, ADG linearly increased with increasing SID ValLys (P = 0.009; 680, 717, 717,712,744, and 726 ± 17.1 g, respectively), whereas no significant treatment differences were observed for G:F (0.467, 0.467, 0.472, 0.474, 0.481, and 0.472 ± 0.0084, respectively). InExp. 2, ADG (quadratic, P = 0.002; 621,662,717,708,708, 726, and 717 ± 16.1 g, respectively) and G:F increased (linear, P < 0.001; 0.415, 0.420, 0.437, 0.429, 0.433, 0.441, and 0.439 ± 0.0046, respectively) with increasing SID VakLys. There was no evidence of experiment x treatment interaction. Therefore, data from the 2 experiments were combined for analysis using experiment and BW block within experiment as random effects. Competing models, namely a broken-line linear model, a broken-line quadratic model, and a quadratic polynomial (QP), were compared using Bayesian information criterion. In the combined analysis, the best-fitting model for ADG was a QP (prediction equation: -1.15 + 4.13 x SID VakLys - 2.78 x SID ValLys2 + 0.012 x initial BW) with optimum ADG estimated at 74.4% (95% confidence interval [CI] 69.5 to > 78.0) SID ValLys. The best-fitting model for G:F was also a QP (prediction equation: -0.04 + 1.36 x SID ValLys - 0.94 x SID ValLys2) with optimum G:F estimated at 72.3% (95% CI 64.0 to > 78.0) SID ValLys. In conclusion, 67% SID VakLys was able to capture 99% of maximum ADG and G:F in 25- to 45-kg pigs. [ABSTRACT FROM AUTHOR]

Three experiments (Exp) were conducted to determine optimal digestible Ile to Lys ratios for male Yield Plus × Ross 708 broilers from approximately 1.0 to 4.0 kg BW. Broilers were fed dose-response diets with inclusions of blood cells that were formulated to contain a gradient of digestible Ile to Lys ratios (0.46 to 0.83). Treatments for Exp 1 to 3 were fed from 21 to 35, 28 to 42, and 35 to 49 d of age, respectively, to target market weights from 2.5 to 4.0 kg. Experiments utilized positive control (PC) diets that did not contain blood cells and were formulated to the same Ile ratios as Treatment 5. Birds and feed were weighed by pen on the first and last days of the experimental period to determine growth performance. Selected broilers were processed and deboned to determine carcass characteristics. For all Exp, quadratic effects (P ≤ 0.001) were observed with BW gain, feed conversion ratio (FCR), breast meat weight, and breast meat yield (BMY) as digestible Ile to Lys ratios increased. Contrasts between PC and Treatment 5 for each Exp displayed no effect of blood cell inclusion with the exception of FCR in Exp 1 (P = 0.001) and BMY in Exp 3 (P = 0.017). Optimum digestible Ile to Lys ratios for Exp 1 were determined to range from 0.640 to 0.725 for growth from 1.0 to 2.5 kg BW (P ≤ 0.001) and breast meat characteristics. In Exp 2, optimum ratios ranged from 0.664 to 0.682 for growth and breast meat characteristics from 1.6 to 3.1 kg BW (P ≤ 0.001). For growth and breast meat characteristics of broilers in Exp 3, optimum ratios ranged from 0.625 to 0.730, from 2.6 to 3.9 kg BW (P ≤ 0.001). Based on these findings, optimum digestible Ile to Lys ratios were determined to range from 0.63 to 0.73 for broilers from 1.0 to 4.0 kg BW., Competing Interests: DISCLOSURES The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

The efficiency of SID Lys utilization (kSID Lys) in gilts and sows during early (days 48 to 52), mid (days 75 to 79), and late gestation (days 103 to 107) was investigated using 88 pregnant females (PIC 1050; 27 gilts, 27 parity 1 sows, 34 parity 2+ sows; 192.96 ± 22.84 kg at days 42 ±1 of gestation) and whole body nitrogen (N) retention balance studies. Females were assigned to 1 of 4 SID Lys levels ranging from 40% to 70% of the daily SID Lys requirements above maintenance for a parity 1 sow according to the NRC (2012) gestating sow model in each gestation period. Experimental diets were isocaloric (3,335 kcal ME/kg) and isoproteic (11.75 % CP) and dietary indispensable AA were set to meet or exceed 100% of AA:Lys ratios. The slope of the linear response to graded SID Lys intake was defined as kSID Lys. With the aim of increasing the accuracy of kSID Lys estimates, gilt data from the current study was combined with gilt data from a previous study conducted at the same facility using 4 SID Lys levels ranging from 60% to 90% of the daily SID Lys requirements above maintenance for gilts according to the NRC (2012) gestating sow model. Whole body Lys retention of the combined gilt data set was assessed with different broken-line and nonlinear models. The kSID Lys was 0.65, 0.38, and 0.52 for early-, mid-, and late-gestation, respectively, in gilts. A linear response to graded SID Lys intake was found in late gestation only in parity 1 and 2+ sows; kSID Lys was determined as 0.44 and 0.52 in late gestation for parity 1 and parity 2+ sows, respectively. There were no differences in kSID Lys in late gestation between parities. For the combined gilt data, the model of best performance (reduced error and greater goodness of fit) was the Hoerl model. Maximum kSID Lys (i.e., g SID Lys retention/g SID Lys intake) in gilts was 0.67, 0.54, and 0.53 in early, mid, and late gestation predicted at 7.2, 9.1, and 13.5 g of SID Lys intake/d, respectively, based on the Hoerl model. Maximum SID Lys retention in gilts was similarly predicted at 8.5, 10.5, and 20.9 g of SID Lys intake per day in early, mid, and late gestation and resultant kSID Lys of 0.61, 0.51, and 0.44, respectively. The findings of this study demonstrate that kSID Lys varies by stage of gestation and SID Lys intake level and that, at least in gilts, a dynamic kSID adjusted for daily intake more adequately reflects biological response and hence allows more precise feeding of pregnant females., (© The Author(s) 2020. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

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., (© The Author(s) 2019. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Early growth is an important determinant of gain and efficiency in growing pigs. A major limiting factor of piglet growth is feed intake. Orexins, newly discovered neuropeptides, may be important regulators of appetite. The orexin gene, which encodes orexin-A and -B, was recently identified in rodents and man. The objectives of this study were to clone the cDNA for porcine orexin, utilize the cDNA sequence information to produce synthetic hormone, and evaluate the effect of orexin administration on feed intake in weanling pigs. Oligonucleotide primers were designed for reverse transcription polymerase chain reaction production of porcine orexin cDNA. The polymerase-chain-reaction products were cloned, sequenced, and found to be 88.5% homologous to the human orexin sequence. Predicted translation of porcine orexin cDNA revealed orexin-A and -B amino acid sequences that were 100% and 96% homologous to the known human peptides, respectively. Porcine orexin-B was synthesized according to the predicted sequence. Twenty-six cross-bred piglets were utilized in three replicates (n = 8-10/replicate). Piglets were weaned between 2-3 wk of age. One week after weaning, equal numbers of animals in each replicate received intramuscular (i.m.) injections of orexin-B (3 mg/kg body weight) or vehicle (sterile water). Feed intake was monitored from -24 to 24 h relative to injection (time 0). The orexin-injected pigs ingested an additional meal at 12 h when compared with the control animals (P = 0.02). Cumulative feed intake was increased by orexin-B administration from 12 to 24 h postinjection (P < or = 0.05). Total feed intake at 24 h was improved by 18% in orexin-treated pigs (P = 0.05). The ability to stimulate appetite during critical periods of early growth, particularly following weaning, could result in significant improvements in swine-production efficiency.