Effect of dietary synbiotic supplementation on performance parameters in turkey poults administered a mixed Eimeria species inoculation I.

This study examined the effects a synbiotic feed additive (PoultryStar meUS) on performance and intestinal health parameters in turkey poults administered a mixed Eimeria inoculation. The synbiotic feed additive consisted of Lactobacillus reuteri, Enterococcus faecium, Bifidobacterium animalis, Pediococcus acidilactici and a fructo-oligosaccharide prebiotic. Dietary treatments began on day of hatch, and poults were placed on a normal starter, starter containing Clinacox, or starter containing PoultryStar until the conclusion of the experiment on day 42. In addition, on day of hatch, all poults, with exception of the negative control, were orally inoculated with Salmonella enterica Enteritidis. On day 16, poults in inoculated treatment groups received an oral dose of Eimeria adenoides and Eimeria meleagrimitis oocysts resulting in a 2 × 3 factorial arrangement of treatments. BW were measured at weekly intervals after challenge, and fecal samples were collected from all pens during day 21 to day 33 to monitor fecal shedding and calculate oocyst per gram of feces. Five day after Eimeria inoculation, inoculated PoultryStar-fed (I-PS) and inoculated Clinacox-fed (I-CL) poults, on average, weighed and gained significantly more weight (P < 0.05) than inoculated controls (I-CON) and were similar to uninoculated treatments. Between day 21 and day 28, I-PS and I-CL poults showed a 23% improvement (P < 0.001) in percent change in BW gained relative to I-CON, and overall weight gain as a percentage was similar to the uninoculated control. Overall incidence of macroscopic intestinal lesions on day 21 and day 28 was low, but I-PS and I-CL poults were generally less positive than I-CON, and no oocysts were detected in the feces of any group except I-CON which cycled as expected. From this study, it can be concluded that incorporating PoultryStar into the diet of poults reared to 6 wk ameliorates and prevents aspects of performance loss and negative impacts on gut health seen with mixed Eimeria inoculation.

Effect of a post-hatch lipopolysaccharide challenge in Turkey poults and ducklings after a primary embryonic heat stress.

The effect of embryonic thermal manipulation on the post-hatch immune response to a lipopolysaccharide (LPS) challenge was studied in Pekin ducklings and turkey poults. Commercial duck and turkey eggs were distributed among four treatments: SS-Control (37.5 °C from embryonic day [ED] 1 to 25); SS-LPS (37.5 °C from ED1 to 25 + LPS at D0 [hatch]); HH-LPS (38 °C from ED1 to 25 + LPS at D0; SH-LPS (37.5 °C from ED1 to 10 and 38 °C from ED 11 to 25 + LPS at D0). At ED16 and ED24, the egg shell temperature of the duck and turkey eggs in the HH and SH treatments were higher (P ≤ 0.01) than the SS treatment. Ducklings and poults in the HH treatment had the lowest yolk free body weight at hatch (P ≤ 0.05). At 24, 48, and 72 h post-LPS injection, ducklings and poults in the HH-LPS treatment had significantly reduced BW compared with the SS-Con treatments (P ≤ 0.05). Ducklings and poults in the SH-LPS and HH-LPS treatments had increased plasma heat shock protein 70 (HSP70) and lower splenic HSP70 mRNA amounts than the SS-LPS treatments at 24, and 48 h post-challenge (P ≤ 0.05). At 48 and 72 h, macrophage nitric oxide (NO) production in ducklings and poults in the SH-LPS and HH-LPS treatments was lower than in the SS-LPS treatments (P ≤ 0.05). Ducklings and poults in the SH-LPS treatment had increased thymocyte proliferation compared to the SS-LPS treatment at 24, 48 and 72 h (P ≤ 0.05). At 24 h, ducklings in the SH-LPS treatment had increased splenic IL-10 and reduced IFNγ and IL-6 mRNA abundance. However, both ducklings and poults in the HH-LPS treatment had increased IFNγ, and IL-10 mRNA abundance compared to the SS-LPS treatment (P ≤ 0.05). At 48 h, SH-LPS ducklings and poults had lower splenic IL-10 mRNA abundance (P ≤ 0.05) while the HH-LPS treatment resulted in comparable splenic IL-10 mRNA compared to the SS-LPS treatment (P ≥ 0.05). Ducklings and poults in the SH-LPS treatment had increased thymic and splenic CD8+/CD4+ ratios at 24 h versus the SS-LPS treatment (P ≤ 0.05). In conclusion, embryonic thermal manipulation from ED11-25 increased extracellular HSP70 release, thymocyte proliferation and IL-10 but decreased splenic HSP70 and IFNγ mRNA amounts at 24 h post-LPS injection. This suggests that mild heat stress during the later stages of incubation could potentially prime the embryonic immune system thereby enhances the immune response as earlier than 24 h to eliminate the inflammatory response without affecting the growth performance by increase the extracellular release of HSP70 in both ducklings and poults. Continuous exposure to the small increase in temperature from ED 1-25 (HH) caused an imbalance between pro (IFNγ)- and anti-inflammatory cytokines(IL-10) which affects hatchling responses to an inflammatory challenge and increased mortality. The amount of extracellular HSP70 could potentially play an important role in modulating the immune response against inflammatory challenges.

Effect of embryonic thermal manipulation on heat shock protein 70 (HSP70) expression and subsequent immune response to post-hatch lipopolysaccharide challenge in Pekin ducklings.

During the course of multi-stage incubation, small locational differences in incubation temperature within a machine are not uncommon and so the goal of this study was to study the immune response of ducklings exposed to thermal manipulation during incubation. Commercial Pekin duck eggs (n = 200) were distributed among four treatment: SS-Control (37.5°C from embryonic day [ED] 1 to 25); SS-LPS (37.5°C from ED1 to 25 + LPS at D0 [hatch]); HH-LPS (38°C from ED1 to 25+ LPS at D0); SH-LPS (37.5°C from ED1 to 10 and 38°C from ED 11 to 25 + LPS at D0). At D0, ducklings received a lipopolysaccharide (LPS) injection. At D1 and D5, the HH-LPS treatment significantly reduced body weight (P ≤ 0.05). At D1 and D3 post-LPS injection, the SH-LPS and HH-LPS treatments significantly reduced splenic and bursal heat shock protein 70 (HSP70), mRNA abundance, and macrophage nitric oxide production compared with the SS-LPS treatment (P ≤ 0.05). At D1, the HH-LPS and SH-LPS treatments had increased splenic IL-10 mRNA and lower MHC I mRNA compared with the SS-LPS treatment (P ≤ 0.05). At D1, the HH-LPS treatment increased splenic IL-6 mRNA and bursal IFNγ mRNA transcription while the SH-LPS treatment reduced splenic IL-6 mRNA compared with the SS-LPS treatment (P ≤ 0.05). The HH-LPS treatment reduced thymocyte proliferation efficiency, while at D1, D3, and D5, the SH-LPS treatment increased thymocyte proliferation efficiency compared with the SS-LPS treatment (P ≤ 0.05). Ducklings in the HH-LPS treatment had a higher splenic CD8+/CD4+ ratio compared to the SS-LPS treatment at D3 post-LPS injection (P ≤ 0.05). In summary, the HH-LPS treatment compromised immunocompetence via decreased NO production and thymocyte proliferation efficiency, while the SH-LPS treatment increased body weight and thymocyte proliferation and reduced IL-6 mRNA abundance. This suggests that an embryonic temperature stress during the latter half of incubation may prime the immune system which may be beneficial during secondary post-hatch inflammatory challenges.

From muscle to food: oxidative challenges and developmental anomalies in poultry breast muscle.

The glycolytic capacity in the "white muscle fibers" found predominantly in broiler and turkey breast muscle have long been recognized as being key components contributing to optimal pH changes post-harvest and the quality of breast muscle products. The pectoralis major (PMAJ) is the predominant breast muscle and is almost exclusively comprised of fast-twitch glycolytic (anaerobic) type IIb muscle fibers (white). In nature, the pectoralis muscles are designed to meet the intense, periodic energy demands of flight in contrast to the continual, oxidative metabolism (aerobic) inherent to the type I slow twitch fibers (red) in the thigh and drum. Within the past decade, it has been recognized that increased breast muscle yield in modern broiler strains may have contributed to muscle myopathies characterized by visible white striations (white striping; WS) often accompanied by surface hemorrhages and areas of extreme firmness (woody breast; WB). The research to date has primarily addressed differences in muscle physiology and processing characteristics in "normal" and "abnormal" muscle samples from older broilers. One hypothesis is that the extensive accretion of protein in a poorly vascularized breast muscle overwhelms the capacity for coping with excessive production of reactive oxygen species and the term "oxidative stress" has been used to describe this condition. There are few recent reports in poultry, however, which have addressed the potential negative physiological effects imposed by multiple layers of fascia surrounding individual muscle fibers, fiber bundles, and intact muscles on circulation and oxidative stability. The objective of this review is to support our hypothesis that the extensive accretion of breast muscle in a poorly vascularized and tightly bound PMAJ could be creating a "compartment syndrome" like condition leading to the development of the WS and WB anomalies in heavy, high yielding birds. Recent gene expression data support this hypothesis.

Transcriptional comparison of myogenesis in leghorn and low score normal embryos.

In a previous study, we reported on a quantitative transcriptomic method which confirmed the temporal transcription of developmental fast skeletal muscle myosin heavy chain (fsMyHC) embryonic isoforms in the embryonic Pectoralis major (PM) of the Single Comb White Leghorn (SCWL). The objective of the current study was to further investigate the transcriptional events underlying embryonic PM growth in the SCWL and a genotype exhibiting partial muscular dystrophy, the Low Score Normal (LSN). We hypothesized that within the SCWL and LSN embryos, there would be differences in the temporal transcription of the fsMyHC isoforms and other myogenic regulatory genes. Samples of PM tissues were collected daily from embryonic day (ED) 6 through ED19. Total RNA was isolated from each PM tissue sample and mRNA transcripts from 28 target genes were simultaneously quantified using a probe hybridization method. Raw data counts were normalized against the geometric mean of 5 housekeeping genes and analyzed using Local Regression (LOESS) smoothing methods. Predicted estimates based on LOESS smoothing were plotted with 95% upper and lower confidence intervals, allowing for line comparisons between the SCWL and LSN. Differences (P < 0.05) were determined by non-overlapping confidence intervals between the SCWL and LSN. Among genes exhibiting line differences (P < 0.05), were the developmental fsMyHC isoforms, transcription factors, growth factors, and proteoglycans. The current study is the first to report transcription of the chicken fast skeletal adult myosin isoform (Cad) during PM myogenesis. Samples were submitted for capillary-liquid chromatography-tandem mass spectrometry analysis which confirmed the translation of all the developmental fsMyHC isoforms including Cad in both lines. The LSN exhibited altered transcription patterns of early myogenic markers (MYOD, MRF4, Cemb1, six4, and pax3) during late embryogenesis, continued transcription of Cvent, and delayed transcription of Cneo.

Early intestinal development and mucin transcription in the young poult with probiotic and mannan oligosaccharide prebiotic supplementation.

Alternative and adjunctive approaches to decreasing the use of dietary antibiotics are becoming popular areas of study. Supplemental probiotics (commensal microbes) and prebiotics (indigestible complex carbohydrates) are 2 dietary approaches to facilitating the intestinal colonization of beneficial bacteria to compete with potential pathogens, thus creating a healthy mucosal environment. The intestinal mucosa is composed of mucin glycoproteins, which play a key role in preventing the attachment of pathogenic bacteria. At hatch, the neonatal turkey intestine is relatively aseptic and vulnderable to bacterial colonization by both commensal and pathogenic microbes. In the current study, we determined the transcription of MUC2, the primary mucin protein produced by goblet cells within the small intestine, and we also measured intestinal morphology immediately post-hatch through d 11. Poults were fed a conventional starter diet, the starter diet supplemented with one of 2 commercial probiotics (A, B), or a commercial mannan oligosaccharide. MUC2 transcription increased from d zero to d 4 post-hatch (P< 0.05), but there was no effect of probiotic or prebiotic supplementation. Villus height and villus area both increased with Probiotic B and mannan oligosaccharide supplementation (P<0.05) and there was a significant d X treatment interaction effect for crypt depth (P=0.007). These results suggest that probiotic and prebiotic supplementation can positively alter the intestinal microenvironment.

Temporal embryonic transcription of chicken fast skeletal myosin heavy chain isoforms in the single comb white leghorn.

There are numerous factors that can significantly influence embryonic development in poultry and thus make simple days of incubation (chronological age) a less than perfect metric for studying embryonic physiology. The developmental fast skeletal muscle myosin (MyHC), the predominant protein in the Pectoralis major (PM), is temporally expressed as a cadre of highly specific developmental isoforms. In the study described herein, a novel molecular technology (NanoString) was used to characterize the myosin isoform transcriptional patterns in the PM of Single Comb White Leghorn (SCWL) embryos. NanoString technology is based on quantitative analysis of the transcriptome through digital detection and quantification of target mRNA transcripts. Total RNA was isolated and gene transcription quantified using NanoString in embryonic muscle samples collected daily from 6 through 19 days of incubation. Data were analyzed using the LOESS smoothing function at a 95% confidence level. The temporal transcription of MyHC isoforms obtained in this study was consistent with the literature at higher specificity and resolution, thus validating NanoString for use in gene transcription analyses. The results support a hypothesis that the transcription patterns of the embryonic MyHC isoforms may be used as molecular clocks to further investigate the developmental relationships underlying embryonic fast skeletal muscle growth and development.

Early intestinal growth and development in poultry.

While there are many accepted "facts" within the field of poultry science that are in truth still open for discussion, there is little debate with respect to the tremendous genetic progress that has been made with commercial broilers and turkeys (Havenstein et al., 2003, 2007). When one considers the changes in carcass development in poultry meat strains, these genetic "improvements" have not always been accompanied by correlated changes in other physiological systems and this can predispose some birds to developmental anomalies (i.e. ascites; Pavlidis et al., 2007; Wideman et al., 2013). Over the last decade, there has been increased interest in intestinal growth/health as poultry nutritionists have attempted to adopt new approaches to deal with the broader changes in the overall nutrition landscape. This landscape includes not only the aforementioned genetic changes but also a raft of governmental policies that have focused attention on the environment (phosphorus and nitrogen excretion), consumer pressure on the use of antibiotics, and renewable biofuels with its consequent effects on ingredient costs. Intestinal morphology has become a common research tool for assessing nutritional effects on the intestine but it is only one metric among many that can be used and histological results can often be interpreted in a variety of ways. This study will address the broader body of research on intestinal growth and development in commercial poultry and will attempt to integrate the topics of the intestinal: microbial interface and the role of the intestine as an immune tissue under the broad umbrella of intestinal physiology.

Influence of plastic slatted floors compared with pine shaving litter on Pekin Duck condition during the summer months.

The management and well-being of commercial Pekin ducks has been studied in the European Union where straw is the predominant litter source. In the United States, however, the most prevalent litter is wood shavings, with a recent trend toward using plastic slatted flooring. A previous study in the United States evaluated the relationship between flooring type (litter, slats) and duck condition during winter months and found very few differences between the 2 in terms of overall duck condition. The purpose of the current study was to reevaluate the 2 flooring systems during the summer months to determine if seasonal differences would interact with flooring type to have an impact on duck condition. Eighteen commercial barns that produce Pekin ducks for Maple Leaf Farms Inc. (Leesburg, IN), located in northern Indiana and southern Wisconsin (n = 9 litter; n = 9 raised slatted floor), were used for this study. Twenty ducks were randomly selected from 5 predetermined areas within each house (n = 100 total) and scored for eye condition, nostril and feather cleanliness, and feather and foot pad quality at 7, 21, and 32 d of age. Environmental data, including carbon monoxide, ammonia, RH, and temperature, were also obtained at each collection day. The only statistical differences in body condition occurred at 7 d; there were more ducks with clear eyes and eye rings on the litter flooring, whereas average nostril scores were better on the plastic slatted floors. Live weight, weight gain per day, flock mortality, and condemnations at the plant were collected, and the only statistical difference was a higher gain per day for ducks reared on slatted floors compared with litter (P < 0.05). There were no differences between flooring systems in the environmental parameters measured within the barns. In summary, there were very few differences between the litter and slatted flooring systems, indicating that there may not be clear advantages for one particular flooring system over the other from the point of view of duck well-being and production.

Influence of raised plastic floors compared with pine shaving litter on environment and Pekin duck condition.

Commercial poultry production management practices have been under increased public scrutiny driven by concerns for food safety and animal welfare. Within the United States, wood shavings and raised plastic floors are common flooring systems used in duck production. It is intuitive that each flooring type would present different management challenges influencing physical characteristics of growing ducks. This study evaluated the relationship between flooring type and duck condition during the winter. Random samples of 20 ducks from 5 predetermined areas (n = 100) were examined in commercial duck houses (n = 9, litter; n = 11, raised plastic slats). Ducks were assessed at 7, 21, and 32 d of age for eye, nostril, and feather cleanliness, feather and foot pad quality, and gait. The data were analyzed to determine the proportion of ducks with a given score. In both housing types, the proportion of 0 scores for foot pad quality improved during the production cycle (P < 0.0001). Feather hygiene declined with age in ducks reared on litter flooring, whereas ducks reared on slatted flooring had cleaner feathers at d 32 (P < 0.011). With the exception of foot pad scores, the majority of ducks had no detectable problems for any single trait. The only main effect due to flooring pertained to feather quality with the proportion of ducks having a 0 or 1 score greater in litter flooring systems than slats (P < 0.05). Overall, the condition of ducks reared, regardless of flooring system, was considered to be good.

Feed restriction delays developmental fast skeletal muscle myosin heavy chain isoforms in turkey poults selected for differential growth.

Genetic selection has been very successful at significantly increasing BW and breast muscle proportion in commercial broiler and turkey strains. The mechanisms of breast muscle growth in poultry and the interactive effects of nutritional status and selection are not fully understood. The hypothesis underlying the current study is that feed restriction, simply as a vehicle for controlling early growth, would delay the temporal expression pattern of neonatal (nMyHC) and adult (aMyHC) fast skeletal muscle myosin heavy chain (MyHC) isoforms in the pectoralis major muscle of turkey poults. The poultry growth model used to evaluate this hypothesis consisted of a randombred control turkey line (RBC2) that represents commercial turkeys of the 1960s and a line developed from the RBC2 by selection for BW at 16 wk of age (F line). The F line has significantly heavier breast muscles than the RBC2 concomitant with increased BW, but the proportion of breast muscle relative to BW is similar. A quantitative indirect ELISA using fast skeletal MyHC isoform specific monoclonal antibodies revealed no significant line differences in the temporal expression of posthatch fast skeletal muscle MyHC in ad libitum fed poults. Feed restriction, however, altered the temporal expression patterns of nMyHC and aMyHC in both F line and RBC2 poults compared with the poults fed ad libitum.

The morphological, material-level, and ash properties of turkey femurs from 3 different genetic strains during production.

Femoral fractures are observed in selective-bred commercial turkeys; however, the etiology of such fractures is unknown. The current study investigated the whole bone morphological, material-level mechanical, and bone ash properties to determine the effect of selective breeding on bone strength. Femora from 3 divergent strains of turkeys, a commercial line, a different selectively bred heavy line (F-line), and a lighter age or weight matched random-bred line (RBC2/R-EQ, respectively), were compared. Bone geometric properties were measured with micro-CT and bone mechanical properties were measured using 3-point bending tests. Whole bone ash quantities were also recorded. Statistics were run using a general linear model multivariate ANOVA (GLM ANOVA). Results showed that at similar ages, the faster growing birds (commercial and F-line) had femurs twice the size of the RBC2 line as measured by cross-sectional area as early as 8 wk into the study. The femurs of the commercial and F-lines also exhibited as much as 20% greater mechanical strength than femurs from the RBC2 line at 16 and 20 wk of age as measured by properties such as elastic modulus and ultimate tensile strength. However, at similar BW, the slower growing R-EQ line had higher mechanical properties than the other lines, with the elastic modulus being 40% greater and the ultimate tensile strength being 37% greater at weights equivalent to those of the commercial and F-lines at 12 wk of age. Moreover, it was observed that the morphological properties (i.e., cross-sectional area, moments of inertia) are largely governed by BW, as there is little difference in the amount gained per week of age across the different lines. Conversely, the mechanical properties, as well as the related ash content, appear to be governed at least in part by time. Therefore, whereas modulation of bone geometry is the key responder for changes in BW, sufficient time for matrix mineralization or maturation or both to occur is also essential for mechanical competence of bone.

A comparison of long bone development in historical and contemporary ducks.

The selection for growth and carcass traits in poultry meat species has contributed to increased interest in understanding and characterizing skeletal growth as the birds struggle to balance skeletal development with increased BW and muscle mass. The objective of this study was to compare the physical characteristics and mineralization of the tibia and femur from commercial Pekin ducks representing circa 1993 and 2010 commercial strains. In 1993, the femur and tibia were collected from 8 ducks at 11 ages between 11 and 53 d. A similar study was done in 2010 in which the femur and tibia were collected from 8 ducks at 12 sample ages between 10 and 49 d. All bones were weighed and the length and width at 50% of length were measured. Each bone was subsequently cut into epiphyseal (top 25% of length) and diaphyseal (midregion at 50% of length) sections. Each bone segment was extracted with ether, hot weighed, and ashed. The 2010 contemporary ducks reached market weight faster than the 1993 ducks. Therefore, statistical comparisons were made at common BW as well as at common ages. The mean tibia length of the 2010 duck was 0.75 cm greater (P < 0.05) at similar ages and similar BW. The percentage ash in the diaphyseal region of the tibia was 3% greater (P < 0.05) in the 2010 versus 1993 ducks. The percentage epiphyseal ash in the femur was 10% lower (P < 0.01) at 10 d and 14 d in the 2010 ducks but there were no significant differences by 18 d of age. The lower epiphyseal ash values at both younger ages and smaller BW in the 2010 contemporary ducks suggests that it is critical to monitor those factors that influence bone mineralization in contemporary ducklings that can achieve market BW at earlier chronological ages.

Comparative proteomic characterization of the sarcoplasmic proteins in the pectoralis major and supracoracoideus breast muscles in 2 chicken genotypes.

The selection processes that have resulted in broiler (meat) and leghorn (eggs) chickens have had very different effects on the pectoralis major and supracoracoideus muscles. The objective of this study, therefore, was to analyze the one-dimensional proteomic profiles of sarcoplasmic protein fractions isolated from the p. major and supracoracoideus muscles collected from 10 chicks from each genotype to compare developmental differences. The sarcoplasmic protein fraction was analyzed by SDS-PAGE. The mean band percentages were analyzed using a mixed model, with strain and muscle type as main effects. Six bands were found to be significantly different across the 2 strains. Strain differences in glycogen phosphorylase, enolase, elongation factor 1, creatine kinase, fructose-bisphosphate aldolase, and glyceraldehyde 3-phosphate-dehydrogenase suggest a genotype-specific shift in energy metabolism during breast muscle growth and development.

The effects of genotype on embryonic development in eggs from divergent turkey genotypes.

Unique turkey genotypes and reciprocal crosses of these lines were used to study the relationship between egg size, posthatch growth potential, and selected aspects of embryonic development. A line of turkeys selected for increased egg production (E), its randombred control line (RBC1), a line selected for increased 16-wk BW (F line), and its randombred control line (RBC2) were the pure lines used in each of 2 experiments. In experiment 1, a sample of E-line hens were mated to either E line (E/E) or RBC1 toms (RBC1/E), and RBC1 hens were mated to RBC1 toms (RBC1/RBC1). Egg weight at set and at 25 d of incubation was significantly lower in the E/E and RBC1/E crosses compared with that of the RBC1/RBC1 eggs. On d 21 and 25 of incubation and at hatch, the yolk-free wet embryo weights of E/E and RBC1/E embryos were similar, and both weighed significantly less than the RBC1/RBC1 embryos (P ≤ 0.001). Similar observations were observed for the residual yolk sac weight at each of those developmental ages. In experiment 2, embryos from the F line, RBC2, RBC1, E, and 2 reciprocal crosses (RBC1/E, E/RBC1) were compared at various time points during the course of incubation. Egg weight was consistently highest in the F line and lowest in the E line and intermediate in the RBC1 and RBC2 lines. Egg weight followed the maternal genotype in the E/RBC1 and RBC1/E reciprocal crosses. On embryonic d 19, 23, and 26, the order of yolk-free weight embryo weights followed closely the pattern observed for egg weight. In summary, egg weight and embryonic development is largely controlled by the maternal genotype. This should be considered when making inference to posthatch selection effects on embryonic development.

Effect of recycled litter on immune cells in the cecal tonsils of chickens.

This experiment was conducted to study selected aspects of the gut immune response in broiler chicks reared on fresh or recycled litter that were fed diets with and without subtherapeutic antibiotic supplementation. All of the chicks were reared in pens that contained either fresh pine shavings (fresh litter) or litter that was recycled for 3 consecutive flocks (recycled litter). The experiment was a 2 × 2 factorial arrangement of treatments with 4 replicate pens (n = 4) per treatment. At 10 and 35 d of age, the cecal tonsils were analyzed for intestinal immune measurements. The cecal tonsils of birds reared on recycled litter had increased IL-1 mRNA (P < 0.01) and a lower percentage of CD4(+)CD25(+) cells at 10 and 35 d of age when compared with those of chicks reared on fresh litter. Birds fed diets supplemented with bacitracin had a reduction in CD4(+) cells (P = 0.01) at 10 d of age when compared with that of chicks that were not fed the antibiotic. The combination of bacitracin supplementation and fresh litter resulted in an approximate 10-fold increase in IL-10 mRNA (P = 0.01) at 10 d of age when compared with that of the unsupplemented chicks in fresh litter. Among those chicks that were not supplemented with bacitracin, the recycled-litter treatment resulted in 25-fold (P = 0.01) and 39-fold (P = 0.02) higher IL-4 mRNA levels at 10 and 35 d of age, respectively, when compared with those of the chicks reared on fresh litter. In conclusion, the intestinal immune response of birds reared on recycled litter is skewed toward an inflammatory response, whereas the fresh litter treatment was skewed toward an anti-inflammatory response. Bacitracin supplementation did not interact with the litter type to alter IL-1 mRNA levels in cecal tonsils, suggesting the low efficiency of bacitracin in alleviating the inflammatory response induced by recycled litter.

Multivariate evaluation of 1-dimensional sarcoplasmic protein profile patterns of turkey breast muscle during early post-hatch development.

Proteins are the main participants in metabolic pathways. However, the analysis of protein abundance patterns associated with those pathways is complicated by the large number of proteins involved. In this study, the objective was to present the application of principal component analysis (PCA) to permit the visualization of developmental proteomic patterns of sarcoplasmic proteins found in breast muscle. Different turkey genotypes and nutritional regimens were used to potentially increase the variability within the sarcoplasmic protein profile. Sarcoplasmic protein fractions from turkey breast muscle samples were collected at 6 ages between 7 to 24 d. Breast muscle samples were collected from 2 distinctly different turkey lines. The poults within each line were either ad libitum or restrict fed. Proteomic PCA plots showed a visual developmental pattern from 7 until 17 d. Multivariate ANOVA highlighted the effect of time point and feeding regimen among profile patterns. The use of different genotypes and feeding regimens influenced variability, which was measured by mean Euclidean distances and ellipses of the PCA plots. These treatment effects, however, did not mask the developmental patterns. After 17 d, the proteomic patterns converged, suggesting that a level of biological stability was achieved regardless of the genotype or treatment. The developmental pattern obtained by the PCA methodology can aid in the planning of more efficient experimental designs so the developmental stage of individuals can be more accurately assessed.

Intestinal physiology and regulatory T cell response to immediate or delayed access to feed and water in Pekin ducklings.

This study investigated the effects of delayed access to feed and water on early duckling growth, selected aspects of intestinal physiology, and immune responses. Ducklings were assigned to one of 2 experimental groups. In one treatment group (referred to as the fed group), feed and water were provided beginning on d 0, and in the other treatment group (referred to as the withheld group), feed and water were withheld until d 2. The ducklings in the withheld treatment had lower BW at 2 and 6 d posthatch than ducklings in the fed group. At 8 d posthatch (6 d postfeeding), the BW of the ducklings in the withheld group was comparable to the BW of the 6-d-old ducklings in the fed group. At 2 d posthatch, withheld ducklings had lower absolute and relative duodenum plus pancreas weight than fed ducklings. At 8 d posthatch (6 d postfeeding), withheld ducklings had higher absolute and relative duodenum plus pancreas weight than fed ducklings at 6 d posthatch. At 2 d posthatch, mucin 5B mRNA content was approximately 2 times lower in withheld ducklings (P = 0.09) than in fed ducklings. At 6 d posthatch, mucin 5b mRNA content was approximately 2.5-fold higher in withheld ducklings (P = 0.07) than in fed ducklings. Delayed access to feed and water increased the CD25(+) cell number in the cecal tonsil at 2, 6, and 8 d posthatch. The IL-10 content of CD25(+) cells was higher in the withheld ducklings than in the fed ducklings at 2 and 6 d posthatch. In conclusion, delaying access of ducklings with no experimental pathogen infection to feed and water has no long-term effects on early growth parameters, intestinal physiology, and immune responses.

Factors affecting endogenous amino acid flow in chickens and the need for consistency in methodology.

Accurate estimation of ileal endogenous amino acid (EAA) losses is important when formulating diets on a standardized ileal digestible amino acid basis. In addition to the undigested and unabsorbed amino acids of dietary origin, amino acids of endogenous origin, which can be basal or diet specific, are found in digesta. The improvement in the techniques used in amino acid analysis as well as a shift from sampling excreta to ileal digesta has resulted in more accurate amino acid digestibility coefficients. Despite this, however, it is important to determine the amino acids in the digesta that are of endogenous origin. Although the need for standardization and its associated advantages is still subject to debate, it is important to evaluate how values from various methodologies compare. Several methods have been used to estimate ileal EAA flow. The classical methods, including the regression method, the use of nitrogen-free diet (NFD), and the fasted cecectomized rooster method, are the most widely used. The criticisms with the last 2 methods are that birds are not in a normal physiological state and the ileal EAA flow is, therefore, underestimated. Different methods have resulted in different endogenous flow estimates, with the NFD method having the lowest values when compared with flows from the regression and highly digestible protein methods. In addition to the influence of methods on ileal EAA flows, the influence of the age of the birds on flow is important. Data on EAA losses are copious in the literature; however, variation in data across and within laboratories calls for investigation of factors contributing to the variation. This review compares results from different methods and examines the issue of repeatability and consistency of EAA losses data from different laboratories. Finally, composition of an NFD for estimating EAA losses is proposed.

Comparison of amino acid digestibility of feed ingredients in broilers, laying hens and caecectomised roosters.

1. This study determined the effect of bird type (broilers, laying hens, or caecectomised roosters) on amino acid digestibility of feedstuffs from 5 plant sources and one animal source. 2. The standardised amino acid digestibility (SAAD) were obtained by correcting apparent ileal amino acid digestibility (AIAAD) values for basal ileal endogenous amino acid (EAA) flow obtained by feeding a N-free diet (NFD) to broilers and laying hens or from fasted EAA flow from caecectomised roosters. 3. The apparent total amino acid (TAA) digestibilities did not differ between broilers and roosters for three of the 6 feed ingredients. 4. Broilers had higher apparent total amino acid (TAA) digestibility than laying hens and roosters when fed on the maize diet (canola meal, maize, and soybean meal). 5. The apparent TAA digestibilities were similar across bird types for the dark distillers' dried grain with solubles, but the apparent lysine digestibility was much lower in the caecectomised roosters (15%) than the broilers (49%) and laying hens (43%). 6. The standardised TAA digestibility values in roosters were higher than in broilers for three of the 6 feed ingredients (canola meal, soybean meal, or meat and bone meal). 7. There were no differences between broilers and roosters, however, in the standardised TAA digestibility values for maize, dark and light DDGS. 8. The standardised TAA digestibility values for laying hens were lower for maize, higher for meat and bone meal, but no different for the remaining ingredients when compared with broilers. 9. The results from this study showed that both the apparent and standardised amino acid digestibility values in caecectomised roosters, laying hens, and broilers ingredients are similar for some, but not all, feed ingredients. 10. Nutritionists should, therefore, be cautious about using digestibility coefficients obtained by different methodologies as values may differ.