FAIMS Enhances the Detection of PTM Crosstalk Sites

Protein post-translational modifications (PTMs) enable cells to rapidly change in response to biological stimuli. With hundreds of different PTMs, understanding these control mechanisms is complex. To date, efforts have focused on investigating the effect of a single PTM on protein function. Yet, many proteins contain multiple PTMs. Moreover, one PTM can alter the prevalence of another, a phenomenon termed PTM crosstalk. Understanding PTM crosstalk is critical; however, its detection is challenging since PTMs occur substoichiometrically. Here, we develop an enrichment-free, label-free proteomics method that utilizes high-field asymmetric ion mobility spectrometry (FAIMS) to enhance the detection of PTM crosstalk. We show that by searching for multiple combinations of dynamic PTMs on peptide sequences, a 6-fold increase in candidate PTM crosstalk sites is identified compared with that of standard liquid chromatography-tandem mass spectrometry (LC-MS/MS) workflows. Additionally, by cycling through FAIMS compensation voltages within a single LC-FAIMS-MS/MS run, we show that our LC-FAIMS-MS/MS workflow can increase multi-PTM-containing peptide identifications without additional increases in run times. With 159 novel candidate crosstalk sites identified, we envisage LC-FAIMS-MS/MS to play an important role in expanding the repertoire of multi-PTM identifications. Moreover, it is only by detecting PTM crosstalk that we can “see” the full picture of how proteins are regulated.

Combined transcriptomic and phosphoproteomic analysis of BMP4 signaling in human embryonic stem cells

Human embryonic stem cells (hESCs) are an invaluable tool in the fields of embryology and regenerative medicine. Activin A and BMP4 are well-characterised growth factors implicated in pluripotency and differentiation. In the current study, hESCs are cultured in a modified version of mTeSR1, where low concentrations of ActivinA substitute for TGFβ. This culture system is further used to investigate the changes induced by BMP4 on hESCs by employing a combination of transcriptomic and phosphoproteomic approaches. Results indicate that in a pluripotent state, hESCs maintain WNT signaling under negative regulation by expressing pathway inhibitors. Initial stages of differentiation are characterized by upregulation of WNT pathway ligands, TGFβ pathway inhibitors which have been shown in Xenopus to expand the BMP signaling range essential for embryonic patterning, and mesendodermal transcripts. Moreover, BMP4 enhances the phosphorylation of proteins associated with migration and transcriptional regulation. Results further indicate the vital regulatory role of Activin A and BMP4 in crucial fate decisions in hESCs.

Vomocytosis of live pathogens from macrophages is regulated by the atypical MAP kinase ERK5

Vomocytosis, or nonlytic extrusion, is a poorly understood process through which macrophages release live pathogens that they have failed to kill back into the extracellular environment. Vomocytosis is conserved across vertebrates and occurs with a diverse range of pathogens, but to date, the host signaling events that underpin expulsion remain entirely unknown. We use a targeted inhibitor screen to identify the MAP kinase ERK5 as a critical suppressor of vomocytosis. Pharmacological inhibition or genetic manipulation of ERK5 activity significantly raises vomocytosis rates in human macrophages, whereas stimulation of the ERK5 signaling pathway inhibits vomocytosis. Lastly, using a zebrafish model of cryptococcal disease, we show that reducing ERK5 activity in vivo stimulates vomocytosis and results in reduced dissemination of infection. ERK5 therefore represents the first host signaling regulator of vomocytosis to be identified and a potential target for the future development of vomocytosis-modulating therapies.

Regulation of Platelet Derived Growth Factor Signaling by Leukocyte Common Antigen-related (LAR) Protein Tyrosine Phosphatase: A Quantitative Phosphoproteomics Study

Intracellular signaling pathways are reliant on protein phosphorylation events that are controlled by a balance of kinase and phosphatase activity. Although kinases have been extensively studied, the role of phosphatases in controlling specific cell signaling pathways has been less so. Leukocyte common antigen-related protein (LAR) is a member of the LAR subfamily of receptor-like protein tyrosine phosphatases (RPTPs). LAR is known to regulate the activity of a number of receptor tyrosine kinases, including platelet-derived growth factor receptor (PDGFR). To gain insight into the signaling pathways regulated by LAR, including those that are PDGF-dependent, we have carried out the first systematic analysis of LAR-regulated signal transduction using SILAC-based quantitative proteomic and phosphoproteomic techniques. We haveanalyzed differential phosphorylation between wild-type mouse embryo fibroblasts (MEFs) and MEFs in which the LAR cytoplasmic phosphatase domains had been deleted (LARΔP), and found a significant change in abundance of phosphorylation on 270 phosphosites from 205 proteins because of the absence of the phosphatase domains of LAR. Further investigation of specific LAR-dependent phosphorylation sites and enriched biological processes reveal that LAR phosphatase activity impacts on a variety of cellular processes, most notably regulation of the actin cytoskeleton. Analysis of putative upstream kinases that may play an intermediary role between LAR and the identified LAR-dependent phosphorylation events has revealed a role for LAR in regulating mTOR and JNK signaling.

LAR protein tyrosine phosphatase regulates focal adhesions via CDK1

Focal adhesions are complex multi-molecular structures that link the actin cytoskeleton to the extracellular matrix via integrin adhesion receptors and play a key role in regulation of many cellular functions. LAR is a receptor protein tyrosine phosphatase that regulates PDGF signalling and localises to focal adhesions. We have observed that loss of LAR phosphatase activity in mouse embryonic fibroblasts results in reduced numbers of focal adhesions and decreased adhesion to fibronectin. To understand how LAR regulates cell adhesion we used phosphoproteomic data, comparing global phosphorylation events in wild type and LAR phosphatase-deficient cells, to analyse differential kinase activity. Kinase prediction analysis of LAR-regulated phosphosites identified a node of cytoskeleton- and adhesion-related proteins centred on cyclin-dependent kinase-1 (CDK1). We found that loss of LAR activity resulted in reduced activity of CDK1, and that CDK1 activity was required for LAR-mediated focal adhesion complex formation. We also established that LAR regulates CDK1 activity via c-Abl and PKB/Akt. In summary, we have identified a novel role for a receptor protein tyrosine phosphatase in regulating CDK1 activity and hence cell adhesion to the extracellular matrix.

FAIMS and Phosphoproteomics of Fibroblast Growth Factor Signaling: Enhanced Identification of Multiply Phosphorylated Peptides

We have applied liquid chromatography high-field asymmetric waveform ion mobility spectrometry tandem mass spectrometry (LC-FAIMS-MS/MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) to the investigation of site-specific phosphorylation in fibroblast growth factor (FGF) signaling. We have combined a SILAC approach with chemical inhibition by SU5402 (an FGF receptor tyrosine kinase inhibitor) and dasatinib (a Src family kinase inhibitor). The results show that incorporation of FAIMS within the workflow results in (a) an increase in the relative proportion of phosphothreonine and phosphotyrosine sites identified, (b) an increase in phosphopeptide identifications from precursors with charge states ≥ +3 (with an associated increase in peptide length), and (c) an increase in the identification of multiply phosphorylated peptides. Approximately 20% of the phosphorylation sites identified via the FAIMS workflow had not been reported previously, and over 80% of those were from multiply phosphorylated peptides. Moreover, FAIMS provided access to a distinct set of phosphorylation sites regulated in response to SU5402 and dasatinib. The enhanced identification of multiply phosphorylated peptides was particularly striking in the case of sites regulated by SU5402. In addition to providing a compelling example of the complementarity of FAIMS in phosphoproteomics, the results provide a valuable resource of phosphorylation sites for further investigation of FGF signaling and trafficking.

Eps8 controls Src- and FAK-dependent phenotypes in squamous carcinoma cells

Eps8 is an actin regulatory scaffold protein whose expression is increased in squamous cell carcinoma (SCC) cells. It forms a complex with both focal adhesion kinase (FAK, also known as PTK2) and Src in SCC cells derived from skin carcinomas induced by administration of the chemical DMBA followed by TPA (the DMBA/TPA model). Here, we describe two new roles for Eps8. Firstly, it controls the spatial distribution of active Src in a FAK-dependent manner. Specifically, Eps8 participates in, and regulates, a biochemical complex with Src and drives trafficking of Src to autophagic structures that SCC cells use to cope with high levels of active Src when FAK is absent. Secondly, when FAK is expressed in SCC cells, thereby meaning active Src becomes tethered at focal adhesion complexes, Eps8 is also recruited to focal adhesions and is required for FAK-dependent polarization and invasion. Therefore, Eps8 is a crucial mediator of Src- and FAK-regulated processes; it participates in specific biochemical complexes and promotes actin re-arrangements that determine the spatial localization of Src, and modulates the functions of Src and FAK during invasive migration.

The non-receptor tyrosine kinase Ack1 regulates the fate of activated EGFR by inducing trafficking to the p62/NBR1 pre-autophagosome

Growth factor signalling regulates multiple cellular functions and its misregulation has been linked to the development and progression of cancer. Ack1 (activated Cdc42-associated kinase 1, also known as TNK2) is a non-receptor tyrosine kinase that has been implicated in trafficking and degradation of epidermal growth factor receptor (EGFR), yet its precise functions remain elusive. In this report, we investigate the role of Ack1 in EGFR trafficking and show that Ack1 partially colocalises to Atg16L-positive structures upon stimulation with EGF. These structures are proposed to be the isolation membranes that arise during formation of autophagosomes. In addition, we find that Ack1 colocalises and interacts with sequestosome 1 (p62/SQSTM1), a receptor for selective autophagy, through a ubiquitin-associated domain, and this interaction decreases upon treatment with EGF, thus suggesting that Ack1 moves away from p62/SQSTM1 compartments. Furthermore, Ack1 interacts and colocalises with NBR1, another autophagic receptor, and this colocalisation is enhanced in the presence of ectopically expressed p62/SQSTM1. Finally, knockdown of Ack1 results in accelerated localisation of EGFR to lysosomes upon treatment with EGF. Structure-function analyses of a panel of Ack1 deletion mutants revealed key mechanistic aspects of these relationships. The Mig6-homology domain and clathrin-binding domain both contribute to colocalisation with EGFR, whereas the UBA domain is essential for colocalisation with p62/SQSTM1, but not NBR1. Taken together, our studies demonstrate a novel role for Ack1 in diverting activated EGFR into a non-canonical degradative pathway, marked by association with p62/SQSTM1, NBR1 and Atg16L.

Regulation of fibroblast growth factor receptor signalling and trafficking by Src and Eps8

Fibroblast growth factor receptors (FGFRs) mediate a wide spectrum of cellular responses that are crucial for development and wound healing. However, aberrant FGFR activity leads to cancer. Activated growth factor receptors undergo stimulated endocytosis, but can continue to signal along the endocytic pathway. Endocytic trafficking controls the duration and intensity of signalling, and growth factor receptor signalling can lead to modifications of trafficking pathways. We have developed live-cell imaging methods for studying FGFR dynamics to investigate mechanisms that coordinate the interplay between receptor trafficking and signal transduction. Activated FGFR enters the cell following recruitment to pre-formed clathrin-coated pits (CCPs). However, FGFR activation stimulates clathrin-mediated endocytosis; FGF treatment increases the number of CCPs, including those undergoing endocytosis, and this effect is mediated by Src and its phosphorylation target Eps8. Eps8 interacts with the clathrin-mediated endocytosis machinery and depletion of Eps8 inhibits FGFR trafficking and immediate Erk signalling. Once internalized, FGFR passes through peripheral early endosomes en route to recycling and degredative compartments, through an Src- and Eps8-dependent mechanism. Thus Eps8 functions as a key coordinator in the interplay between FGFR signalling and trafficking. This work provides the first detailed mechanistic analysis of growth factor receptor clustering at the cell surface through signal transduction and endocytic trafficking. As we have characterised the Src target Eps8 as a key regulator of FGFR signalling and trafficking, and identified the early endocytic system as the site of Eps8-mediated effects, this work provides novel mechanistic insight into the reciprocal regulation of growth factor receptor signalling and trafficking.

Differential phosphoproteomics of fibroblast growth factor signaling: identification of Src family kinase-mediated phosphorylation events

Activation of signal transduction by the receptor tyrosine kinase, fibroblast growth factor receptor (FGFR), results in a cascade of protein−protein interactions that rely on the occurrence of specific tyrosine phosphorylation events. One such protein recruited to the activated receptor complex is the nonreceptor tyrosine kinase, Src, which is involved in both initiation and termination of further signaling events. To gain a further understanding of the tyrosine phosphorylation events that occur during FGF signaling, with a specific focus on those that are dependent on Src family kinase (SFK) activity, we have applied SILAC combined with chemical inhibition of SFK activity to search for phosphorylation events that are dependent on SFK activity in FGF stimulated cells. In addition, we used a more targeted approach to carry out high coverage phosphopeptide mapping of one Src substrate protein, the multifunctional adaptor Dok1, and to identify SFK-dependent Dok1 binding partners. From these analyses we identify 80 SFK-dependent phosphorylation events on 40 proteins. We further identify 18 SFK-dependent Dok1 interactions and 9 SFK-dependent Dok1 phosphorylation sites, 6 of which had not previously been known to be SFK-dependent.

To gain a further understanding of the tyrosine phosphorylation events that occur during FGF signaling, with a specific focus on those that are dependent on Src family kinase (SFK) activity, we have applied SILAC combined with chemical inhibition of SFK activity to search for phosphorylation events that are dependent on SFK activity in FGF stimulated cells. Also, we used a targeted approach to carry out high coverage phosphopeptide mapping of one Src substrate protein, Dok1, and to identify SFK-dependent Dok1 binding partners.

Database search strategies for proteomic data sets generated by electron capture dissociation mass spectrometry

Large data sets of electron capture dissociation (ECD) mass spectra from proteomic experiments are rich in information; however, extracting that information in an optimal manner is not straightforward. Protein database search engines currently available are designed for low resolution CID data, from which Fourier transform ion cyclotron resonance (FT-ICR) ECD data differs significantly. ECD mass spectra contain both z-prime and z-dot fragment ions (and c-prime and c-dot); ECD mass spectra contain abundant peaks derived from neutral losses from charge-reduced precursor ions; FT-ICR ECD spectra are acquired with a larger precursor m/z isolation window than their low-resolution CID counterparts. Here, we consider three distinct stages of postacquisition analysis: (1) processing of ECD mass spectra prior to the database search; (2) the database search step itself and (3) postsearch processing of results. We demonstrate that each of these steps has an effect on the number of peptides identified, with the postsearch processing of results having the largest effect. We compare two commonly used search engines: Mascot and OMSSA. Using an ECD data set of modest size (3341 mass spectra) from a complex sample (mouse whole cell lysate), we demonstrate that search results can be improved from 630 identifications (19% identification success rate) to 1643 identifications (49% identification success rate). We focus in particular on improving identification rates for doubly charged precursors, which are typically low for ECD fragmentation. We compare our presearch processing algorithm with a similar algorithm recently developed for electron transfer dissociation (ETD) data.

Strategies for improved protein database searching of electron capture dissociation (ECD) mass spectrometry data sets are presented. We show that identification rates can be significantly increased (19−49%) by a combination of presearch processing of ECD mass spectra, optimizing search parameters, and postprocessing of the results.

SLoMo: automated site localization of modifications from ETD/ECD mass spectra

Recently, software has become available to automate localization of phosphorylation sites from CID data and to assign associated confidence scores. We present an algorithm, SLoMo (Site Localization of Modifications), which extends this capability to ETD/ECD mass spectra. Furthermore, SLoMo caters for both high and low resolution data and allows for site-localization of any UniMod post-translational modification. SLoMo accepts input data from a variety of formats (e.g., Sequest, OMSSA). We validate SLoMo with high and low resolution ETD, ECD, and CID data.

Large scale localization of protein phosphorylation by use of electron capture dissociation mass spectrometry

We used on-line electron capture dissociation (ECD) for the large scale identification and localization of sites of phosphorylation. Each FT-ICR ECD event was paired with a linear ion trap collision-induced dissociation (CID) event, allowing a direct comparison of the relative merits of ECD and CID for phosphopeptide identification and site localization. Linear ion trap CID was shown to be most efficient for phosphopeptide identification, whereas FT-ICR ECD was superior for localization of sites of phosphorylation. The combination of confident CID and ECD identification and confident CID and ECD localization is particularly valuable in cases where a phosphopeptide is identified just once within a phosphoproteomics experiment.

Fertility in men with cystic fibrosis: an update on current surgical practices and outcomes

BACKGROUND

Men with cystic fibrosis (CF) have bilateral absence of the vas deferens causing an obstructive azoospermia that is not amenable to surgical correction. Advances in the field of reproductive medicine allow for the procurement of viable sperm and facilitate fertilization and pregnancy in couples where the man has CF.

OBJECTIVES

To describe patient anatomy and semen characteristics and to determine the pregnancy rates of couples in whom the male partner has CF and who have undergone microsurgical epididymal sperm aspiration coupled with in vitro technology, specifically intracytoplasmic sperm injection (ICSI).

DESIGN

Retrospective analysis.

SETTING

Clinical department of urology and two reproductive medicine units.

PATIENTS

Thirteen married men with CF who were referred for infertility.

INTERVENTIONS

History, physical examination, semen analysis, transrectal and renal ultrasonography, CF mutation analysis, and microsurgical sperm aspiration coupled with ICSI.

RESULTS

All 13 men had low-volume azoospermia, absent vasa, and aplasia/hypoplasia of the seminal vesicles. CF mutation analysis was carried out in 11 of 13 men, and 9 of 11 were DeltaF508 homozygous. Eight men underwent microsurgical sperm aspiration, and their partners underwent one or more cycles of ICSI. Five couples (62.5%) achieved a pregnancy, with four couples delivering (three sets of twins and one singleton).

CONCLUSIONS

CF in men is accompanied by bilateral vasal aplasia. The resultant obstructive azoospermia can be treated quite successfully with a combination of sperm aspiration and ICSI. It is important for physicians involved in the care of men with CF to convey the message that prospects for fatherhood are excellent with current technology.

ACAPELLA-1K, a capillary-based submicroliter automated fluid handling system for genome analysis

The Genomation Laboratory in the Electrical Engineering Department at the University of Washington has been developing an automated, high-throughput, submicroliter-scale fluid-handling system for use in molecular biology, especially as part of the Human Genome Project and other high-throughput DNA sequencing endeavors. Small glass capillaries enable the preparation, handling, and monitoring of 1-microliter reaction volumes. The Genomation Laboratory, with corporate partners Orca Photonic Systems, Inc. and Engineering Arts, has developed modules for aspiration, dispensing, mixing, transport, and rapid thermal processing of biological samples contained in glass capillaries. The ACAPELLA-1K is the first integration of these modules, designed to process 1000 samples in an eight-hour day. It has served as a test bed for the technologies as well as for performing biological experiments in conjunction with the University of Washington Genome Center. This system and related results are presented in this paper. A video of the system in operation is provided at. The Genomation Laboratory is presently developing the next-stage ACAPELLA-5K system based on the results of the ACAPELLA-1K system.

Evaluation of molt induction to body weight loss of fifteen, twenty, or twenty-five percent by feed removal, daily limited, or alternate-day feeding of a molt feed

Postmolt egg production variables were compared among hens induced into molt by feed removal, by limited daily feeding of a low-density and low-energy molt feed at 22.8 g per hen, or by limited alternate-day feeding at 45.5 g per hen, until approximate body weight loss of 15, 20, and 25% was obtained. Hens were housed two per cage (25.4 x 45.7 cm) in a house of environmental design, and photoperiod was reduced to 8 h during the 28-d molt period. When target body weight loss was obtained, packed cell volume was determined and hens were maintained on 45.5 g/d of 1.2% calcium prelay feed through the 28-d molt period. Egg production and mortality were recorded daily; egg weight, egg specific gravity, body weight, and feed intake were recorded at 4-wk intervals postmolt. Packed cell volume of hens molted by feed removal (36.4%) was higher (P < .01) than that of alternate-day (34.1%) or daily limited (33.6%) hens. Hens that lost 25% of their body weight had higher packed cell volume (36.3%) than hens that had body weight loss of 20% (34.4%) or hens that lost 15% (33.4%). Postmolt mortality and egg production were not different (P > .05) as a result of molt induction method or percentage body weight loss. At the 4th wk postmolt, body weights were 50 and 57 g heavier for hens that had lost 15% body weight than those that lost 25 or 20%, respectively, and egg production was negatively linearly related to body weight loss.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of two different molting procedures on a Salmonella enteritidis infection

Previous studies have shown that inducing a molt using feed removal exacerbated an intestinal infection by Salmonella enteritidis (SE). The current study was conducted to determine whether inducing a molt using a molt diet would still cause a pause in egg laying but not exacerbate an intestinal SE infection. In Experiments 1 and 2, hens were either provided ad libitum access to layer feed (control), fed 45 g molt diet (molt-feed) daily, or deprived of feed for 14 d (molted), and were orally infected with 1 x 10(7) SE on Day 4 of molt. Egg lay ceased in hens subjected to both molt treatments. The percentage of hens shedding SE did not differ among treatment groups in Experiment 1, whereas in Experiment 2 the molted hens had significantly higher shed rates than the controls on Days 10, 17, and 24 postinfection and the molt-feed hens on Days 17 and 24 postinfection. Compared with both fed groups of hens, the molted hens shed significantly more SE in Experiment 1 on Day 10 postinfection, and in Experiment 2 the molted hens shed significantly more SE on all 4 sampling days. In Experiment 3, subgroups of hens within each treatment group received serial 10-fold dilutions of SE and intestinal shedding of the organism in each subgroup was determined 7 d later. The 50% infectious dose (ID50) was calculated for each treatment group from these shedding results.(ABSTRACT TRUNCATED AT 250 WORDS)

Beak trimming and sex effects on behavior and performance traits of large white turkeys

The effects of beak trimming at day old on performance and behavioral activities of male and female Large White turkeys were evaluated. One hundred and twenty poults of each sex were evenly assigned to 20 treatment pens and evaluated for body weight, feed usage, and livability characteristics to 18 wk of age. Behavioral observations were conducted for feeding, drinking, sleeping, huddling, resting, and agonistic activities. Beak trimming affected body weight and feed usage levels for the sexes differently. From 6 wk, trimmed males were significantly heavier than untrimmed males, whereas untrimmed females were heavier than trimmed females from 12 wk. Similar to body weights, feed usage levels from 13 to 18 wk were higher for trimmed males compared with untrimmed males and lower for trimmed females compared with untrimmed females. Feed conversion ratios after 12 wk and survival to 18 wk were not affected by trimming treatment. Livability rates, however, were lowest for untrimmed males and highest for untrimmed females. Effects on behavioral activities were confined primarily to the brooding and early rearing phases. Beak trimming reduced feeding activity of females and drinking activity of both males and females during the first 2 wk. Sleeping, huddling, and resting activities were increased by beak trimming for both sexes during brooding. Agonistic acts were reduced by beak trimming main effect at 3 and 6 wk. Trimmed males committed fewer agonistic acts at 6 wk than untrimmed males.

Penile ecthyma gangrenosum. Complication of drug addiction

We present a case of ecthyma gangrenosum involving the penis in an IV drug abuser probably resulting from direct arterial septic embolization from a femoral injection site. An increased awareness of this condition is essential because misdiagnosis has been reported in up to 100 percent of cases. Prompt diagnosis is essential to begin appropriate therapy.

Comparison of the Cornell and Bio-mittent reduced lighting programmes for laying hens

The Cornell (8L:10D:2L:4D) and (Ralston Purina) Biomittent lighting programmes were applied to a commercial strain of White Leghorn laying hens from 20 to 64 weeks of age. 2. The egg production of hens exposed to the Cornell lighting was reduced compared to the Bio-mittent programme. 3. Food consumption was less and efficiency of utilisation significantly improved for the Cornell programme during phase I (20 to 36 weeks) of the study. Significant differences were not observed during phase II (37 to 64 weeks) or for the whole cycle (20 to 64 weeks). 4. Body weights were significantly greater for hens exposed to the Bio-mittent programme during both phases I and II. 5. Egg weights, egg mass and egg weight distributions were not different for hens exposed to the 2 programmes. 6. Food costs and the margin of income over food costs were significantly in favour of the Cornell programme during phase I. However, differences for phase II and the complete cycle were not significant. 7. The Bio-mittent programme offered a computed advantage of 14.4% fewer hours of light usage compared to the Cornell programme.

Population size, cage area, and dominance rank effects on productivity and well-being of laying hens

The effect of two cage population sizes (four vs. six/cage) and two cage area treatments (316 cm2 vs. 406 cm2/bird) were compared in a nonconfounded design while maintaining feeder space constant (8.9 cm/bird) for egg production performances and behavioral and physiological indicators of well-being of laying hens. Egg production rates were determined for all members of each cage group (palpations at 48 to 50 wk) and on a cage group basis (20 to 60 wk). Heart weights, plasma corticosterone levels, durations of tonic immobility (TI), and plumage conditions were compared for top and bottom birds in the dominance ranks. Significant reductions in egg production were observed for low ranking hens in the high density (4 and 6/316-cm2) treatments. In addition, high ranking hens of the 6/316-cm2 treatment produced fewer eggs than high ranking hens in the 4/316-cm2 treatment. When high and low ranking individuals were housed in single-hen cages, egg production was improved relative to performances in the social environments. Heart weights of hens, as a percentage of body weight, were increased in the low ranking hens and for hens in the smaller cage size. Plasma corticosterone did not prove to be a useful indicator of well-being. Low ranking individuals had greater durations of TI but differences in feather condition were not detected. The results support the contention that appropriate population sizes and cage space allocations can be determined that will optimize the performance and welfare of layers in cage environments.

Effects of population size and cage area on agonistic activity and social structure of White Leghorn layers

Four caging environments consisting of two population sizes (4 vs. 6 birds/cage) and two cage area allocations (316 vs. 406 cm2/bird) were evaluated for their effects on agonistic activity, social structure, and egg production of Single Comb White Leghorn layers. Wire battery laying cages were designed and constructed to study these effects in a nonconfounded approach while maintaining feed trough space constant. Agonistic activities and dominance structure for the treatment groups were assessed during Weeks 23 to 26 and 37 to 40; egg production was obtained for Weeks 20 to 40. Cage groups demonstrated a high degree of linearity (K) for dominance hiearchies during both observational periods. Values for K ranged from a low of .69 during Period 1 to as high as .91 during Period 2. Cage groups were also very stable over observation periods; correlation coefficients for dominance ranks between Periods 1 and 2 averaged .95 and .89 for the four and six-bird groups, respectively. Greater cage area and population size resulted in more agonistic activity during Period 1, but only in the 6/406 cm2 treatment during Period 2. The alpha individual was responsible for the most aggressive acts committed in all cage groups (40 to 50%). Aggressive activity was observed to decline in a linear manner with declining dominance rank. Egg production was significantly affected by population and density treatments during Period 2; however, correlations between aggressive acts per cage and egg production were not generally significant.

Effects on productivity and aggressive behavior of laying hens of solid versus wire cage partitions and bird density

The effects of solid metal cage partitions or wire mesh cage partitions and two cage densities (5 or 7 birds/60.9 cm X 35.6-cm shallow cage) on production performance traits, aggressive behavior, and feather covering of White Leghorn layers were assessed from 20 to 60 wk of age. Type of cage partition had no significant effects on any of the traits measured. Higher cage density, however, was associated with significantly lower hen-day egg production, feed usage, final body weights, and feather covering. No differences were observed for egg weights, egg loss, mortality, or aggressive head pecking activity of birds housed in the two cage densities.

Performance and physiological profiles of high dietary zinc and fasting as methods of inducing a forced rest: a direct comparison

Equal periods of fasting or high zinc feeding as a means of inducing a forced rest were examined. Single Comb White Leghorn hens (60 weeks of age) were fasted (F) or fed a layer diet containing 20,000 ppm zinc (Zn) for either 4 or 10 days in a 2 X 2 factorial arrangement of treatments. Feed intake was markedly depressed in the first day of high zinc feeding and averaged 10.7 and 6.1 g/hen-day during the 4 or 10 days of Zn feeding. Body weight losses of hens fasted or fed high dietary zinc were not significantly different. Egg production rate was highest for hens treated 10 days (both F and Zn) in the immediate weeks following the rest. However, over the entire 6-month experimental period, there were no significant differences among the four treatments. Ovary and oviduct regressed similarly in F and Zn hens. Tissue zinc concentration greatly increased during zinc feeding, especially in the pancreas, and rapidly returned to normal upon refeeding a normal layer diet. Fasting also caused a substantial increase in tissue zinc. The results show that the effectiveness of zinc as a forced-resting agent for hens is related to changes in feed intake.

Response to divergent selection for early growth of chickens fed a diet deficient in selenium

Three generations of divergent selection for 21-day growth response to a diet deficient in selenium (-Se) were bred using a meat-type chicken. The Athens-Canadian Randombred (AC) population of chickens served as the base population for this study. Mass selection was used to establish a -Se refractory line (SDR) and a -Se susceptible line (SDS). A genetic control line was maintained during the selection process to facilitate evaluation of the responses of the selected lines. The SDR males and females had an average of 17% increase in weight gain at 21 days of age when fed the -Se diet compared with the control line males and females fed the same diet for the three generations of selection. The SDS line had an average reduction in weight gain of 27% during the same period of selection. A difference of 25 g was observed between the mean body weights of SDR males and females and between the SDS males and females after one generation of selection. By the third generation of selection, the difference between SDR and SDS males had increased to 31 g, whereas the SDR and SDS females differed by 41 g. Early response to selection was asymmetrical because the response was greater in the SDS than in the SDR line. Response to selection, however, generally declined after the first generation. Realized heritability estimates for individual generations for this trait were variable (ranging from -.26 to .95), but cumulative estimates (.15 to .39) for growth through three generations were similar to those reported for chickens and quail.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cage and floor pen management on behavior, production, and physiological stress responses of laying hens

Behavior, physiology, health, egg production, and egg quality characteristics of laying hens housed either 1/1394-cm2 cage (S), 2/1394-cm2 cage (HD), 2/2788-cm2 cage (LD), or in floor pens (P), each containing 25 hens, were monitored in order to assess hen welfare in different management systems. Egg production was highest in P and S hens. There were no differences among treatment groups in feed efficiency, egg weight, or egg taste, although egg shell breaking strengths were lower in HD hens despite their relatively low egg production. Blood spots were most common in eggs from caged hens. With respect to behavior, penned hens locomoted more, spent less time in stationary exploration than caged birds, and utilized nest boxes for activities in addition to egg laying. The HD hens fed less frequently than did the LD, and HD cage pairs engaged less frequently in simultaneous feeding, drinking, and resting behavior than LD pairs. Plasma corticosterone levels were initially found to be higher in pens than cages; this difference disappeared when the use of trap-nesting to capture P birds for sampling was discontinued. Nighttime corticosterone levels were higher in HD hens. In contrast, primary and secondary hemagglutination titers to sheep erythrocyte (SRBC) antigen, heterophil to lymphocyte ratios, hepatic zinc metallothionein, serum zinc, and body weights did not differ among treatments. Mortality, however, was lower in pens. It was concluded that, although there were striking dissimilarities in behavior between the pen and cage environments, physiological and production data did not provide evidence of stress associated with cage housing per se. High density caging, however, may be a stressor; this is discussed with reference to other research.

Behavioral effects of intraventricular dibutyryl cyclic AMP in domestic fowl

Intraventricular administration of dibutyryl cyclic AMP (dbcAMP) to domestic fowl induced behaviors within 60 seconds which persisted for 7-120 minutes. Stereotyped head movements and increases in preening were observed at the lowest dose (50 nmol), while at higher doses (150 and 225 nmol) head movements were interspersed with escape behavior, increases in locomotor activity, salivation and a loss of coordination. Administration also elicited vocalizations, mainly laying and type 1 warning calls. These calls contained many abnormal elements, possibly caused by relaxation of the syringeal musculature. The rate of calling was influenced by testosterone, being greater in hens and capons than in roosters or capons implanted with testosterone propionate. Caponization also intensified escape behavior. No behaviors were induced by administration of the hydrolysis product of dbcAMP, butyric acid. These behavioral effects of dbcAMP are similar to those reported to occur during electrical stimulation of loci in the avian brain.

Effects of feed restriction on growth and metabolism of replacement pullets

The effects of feed restriction on lipogenesis, carcass composition, and protein utilization were investigated. Two feed restriction programs were used: restricted duration of feeding (RDF) whereby pullets had access to feed for 7 or 9 hr/day and restricted access to feed (ADF) in which feed was available on alternate days. A control group received the same diet as the restricted groups but on an ad libitum basis. The feeding programs were applied to a white egg and brown egg strain of commercial laying hens from 1 until 5 weeks of age or from 3 days (RDF) or 10 weeks (ADF) until 19 weeks of age. The ADF restriction resulted in 12 to 25% decrease in body weights at 5 weeks and 5 to 11% decrease in body weights at 18 or 19 weeks. The RDF depressed body weights 24% at 5 weeks and 2% at 18 weeks. The RDF and ADF increased hepatic malic enzyme and glutamic oxaloacetic transaminase activities in both age groups. Plasma uric acid and hepatic glutamic pyruvic transaminase were affected, but not consistently, by ADF. It is hypothesized that ADF and RDF lead to increased lipogenesis and increased utilization of amino acids as sources of energy. Under conditions of mild restriction, this may result in increased carcass fat content.

A comparison of controlled feeding programs for maximizing returns of white Leghorn layers

Three controlled feeding programs initiated after peak egg production and a full feeding program were evaluated for their effects on production and income performance of White Leghorn layers. Program 1 consisted of full feeding from 20 to 64 weeks of age. Controlled feeding programs were initiated at 36 weeks and consisted of feeding approximately 105 g/bird/day to 64 weeks (Program 2), a phase reduction feeding program consisting of feeding approximately 105 g/bird/day to 53 weeks of age followed by feeding approximately 95 g/bird/day to 64 weeks (Program 3), and feeding approximately 95 g/bird/day continuously from 36 weeks (Program 4). Controlled feeding programs resulted in significant (P less than .05) reductions in total feed usage compared to full fed birds. Eggs per hen, however, were significantly (P less than .05) reduced only for feeding Programs 3 and 4, and egg weights were reduced only with feeding Program 4. Egg mass production and body weights were significantly affected by controlled feeding programs. Egg grade distributions were not significantly (P greater than .05) different among Programs 1, 2, or 3; however, Program 4 produced a significant (P less than .05) increase in the percentage of medium grade eggs obtained. Egg incomes over pullet and feed costs favored all controlled feeding programs, demonstrating that maximum production levels do not always mean maximum returns.

Forced resting by high dietary zinc: tissue zinc accumulation and reproductive organ weight changes

An experiment was conducted to investigate the effects of high dietary zinc, as a means of inducing a forced-rest, on selected organ accumulation of zinc and reproductive function in terms of ovary and oviduct weight in the laying hen. Single Comb White Leghorn hens laying approximately at 60% production were fed either 10,000 ppm zinc as zinc oxide (10 Zn) or 20,000 ppm zinc (20 Zn) for a period of 4 days. At the initiation of the experiment (Day 0), five hens were killed and organs obtained for analysis. On 4, 10, 16, and 22 days afterward, similar samples were obtained from 5 hens per treatment. Ovary and oviduct weights were determined and zinc analysis performed on the latter as well as liver, kidney, and pancreas. The brief 4-day feeding of either high zinc diet caused a marked 80% reduction in ovary weight by Day 10. The oviduct, although less affected, was still reduced approximately 60% in weight after feeding either 10 Zn or 20 Zn for 4 days. The oviduct exhibited a statistically significant elevation in zinc concentration on Day 4 but was normal by Day 10 (6 days following the refeeding of a normal diet) and not different between treatments. There was extensive accumulation of zinc in kidney, liver, and especially pancreas after 4 days of feeding either 10 Zn or 20 Zn. The level of dietary zinc had no effect on the extent of accumulation in any tissue. The depletion of tissue zinc roughly corresponded to the magnitude of increase in the concentration of zinc observed at Day 4. Possible ramifications of the dramatic increase observed in pancreatic zinc were discussed. We concluded that feeding either 10 Zn or 20 Zn as a means of inducing a forced rest effects a marked and rapid reduction in ovary and oviduct weight as well as an extensive increase in renal, hepatic, and especially pancreatic zinc.

High dietary zinc and fasting as methods of forced resting: a performance comparison

A study was conducted to compare fasting and high dietary zinc as procedures to induce a forced rest of laying hens. Five to six replicates (25 hens each) of Single Comb White Leghorn hens laying approximately 60% were fasted for 10 days (fasted) or fed either 10,000 ppm zinc (10 Zn) or 20,000 ppm zinc (20 Zn) for a period of 4 days. A fourth treatment consisted of feeding 20,000 ppm zinc for 8 days (20 Zn-8). During the rest-inducing period, hens consumed little of either high zinc diet. Four-day intake by 20 Zn hens averaged 17.6 +/- .2 g/hen/day compared to 32.6 +/- 1.5 g/hen/day (means +/- SEM) for 10 Zn hens. Those fed 20 Zn-8 consumed the least amount, 12.6 +/- .2 g/hen/day during the 8 days of high zinc feeding. Body weight loss of hens in this last group was comparable to hens fasted for 10 days (fasted), i.e., 24.6 +/- .3% vs. 27.6 +/- .4%. Weight loss of hens in the remaining two groups reflected, to some extent, differences in feed consumption. The 20 Zn hens lost significantly more body weight during the 4-day period when compared with 10 Zn hens (16.2 +/- .4% vs. 11.9 +/- .5%). Each treatment resulted in a sharp drop in egg production. By the 5th day, fasted, 20 Zn, and 20 Zn-8 hens had ceased producing eggs. Egg production by 10 Zn hens declined at a slightly slower rate. There were considerable differences in post-rest egg production among the various treatments.(ABSTRACT TRUNCATED AT 250 WORDS)

Production and income performance of white leghorn layers feed restricted at various stages of production

Four feeding programs were conducted to evaluate the effects of feed restriction initiated at different stages of production on performance and economic returns of White Leghorn layers. Program 1 consisted of full feeding from 20 weeks of age. Feeding Programs 2, 3, and 4 consisted of feeding 105 g/bird/day starting at 28, 38, and 45 weeks of age, respectively. Information on production performance and egg grade distributions were collected and used to compare egg returns over feed costs for feed costs of 140, 160, and $180/ton and egg prices of 52, 50, 48 and 26 cents for extra-large, large, medium, and small sizes of eggs. Prices for mediums varied from -2 to -8 cents under large. Early feed restriction (Program 2) resulted in reduced egg production, feed usage, body weights, and average egg weights. Restriction from 38 and 45 weeks (Programs 3 and 4) resulted in levels of egg production comparable to the full-fed hens. Significantly (P less than .05) less feed was used, smaller body weights and egg weights were obtained, and more medium grade eggs were produced with Programs 3 and 4. Egg incomes over feed costs were greatest for the restriction programs initiated from 38 and 45 weeks of age.

The effects of management program and social rank on behavior and productivity of white leghorn layers in cages

The effects of three management programs for behavioral and production performance traits of caged layers were evaluated. Management programs consisted of 5 birds per cage; (1) in deep cages, (2) shallow cages, both with full feed, and (3) shallow cages with restricted feeding. Feeding frequencies, aggressive activity, egg production, egg weights, body weights, and egg shell strengths were determined for social ranks within cage groups. Feed usage was determined for management programs only. Social rank effects for feeding frequencies were observed (P less than or equal to .05) with reduced feedings for the lowest rank in Programs 1 and 3. Egg production was significantly (P less than or equal to .05) reduced for the lowest social rank with the feed restriction program. No differences for body weights, weight gains, egg size, and shell breaking strength were observed among social ranks. Management program significantly (P less than or equal to .05) affected aggressive activity, body weights and feed usage. Birds in shallow cages with full feeding recorded the fewest number of total aggressive acts, whereas birds in shallow cages with feed restriction recorded the most total aggressive acts. Birds in shallow cages with full feeding had larger body weights, weight gains, and used more feed.

Effects of feed restriction on production performance of replacement pullets

Two experiments were conducted to evaluate the effects of feed restriction on production performance of egg production pullets. In Experiment 1, two brown-egg strains (A and B) were subjected to full feeding, a restricted duration of feeding program, and a quantitative feed restriction program. Two White Leghorn strains (C and D) were subjected to full feeding and restricted duration of feeding only. For Experiment 2, only strains B and D were used and an additional restricted duration of feeding program was studied. Pullets were maintained on these programs to 20 weeks of age. Production data were collected to 66 and 62 weeks of age for Experiments 1 and 2, respectively. Restricted duration of feeding was found to depress body weight by 2 to 3%, and quantitative feed restriction depressed body weight by 5% with feed intake depressed by the same magnitudes. Feed restriction at these levels had no significant effects on hen-day or hen-housed egg production, egg weight, egg mass, or egg grades. Net egg income over feed cost was significantly improved by feed restriction in Experiment 2. Pullets on quantitative restriction produced the greatest returns. This was due to increased numbers of large eggs and the decrease in rearing feed consumption. Feed restriction had no effect on mortality or sexual maturity. Feed consumption, body weight, egg weight, and economic returns were higher for the heavy strain of pullets. Mortality was highest within the light strains.

Response to bidirectional and reverse selection for mating behavior in Japanese quail Coturnix coturnix japonica

Reported is a genetic analysis of mating behavior in male Japanese quail. Data were obtained from replicated experiments involving 12 generations of divergent selection for high and low cumulative number of completed matings (CNCM). No trait measured in the randombred control population changed significantly over time. Asymmetrical responses between the divergent lines were observed during various phases of selection. Reversed selection showed that additive genetic variance remains in the high lines. Small and unimportant were drift and error variances. Genetic and phenotypic relationships between CNCM and body weight were small but positive, while those between CNCM and relative aggressiveness were positive and intermediate. Also positive and intermediate were the correlations between CNCM and cloacal gland size.

Microscopic effects of meglumine iothalamate. Ventriculography in canines

Meglumine iothalamate, an iodinated contrast agent, is commonly used in humans for roentgenographic outlining of cerebral ventricles. Although clinical studies have shown meglumine iothalamate to be less toxic than other radiopaque materials, its microscopic effects on brain tissue have never been studied in a controlled manner. For this study canine cerebral tissue was exposed to intraventricular saline or saline plus meglumine iothalamate and the results were compared by light microscopy. Reactive changes were found in both groups. They occurred with greater frequency and degree in the group exposed to meglumine iothalamate, but permanent damage to brain tissue, did not occur.