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The knowledge of the exact oxygen partial pressure in tissue is crucial for patient care and in the treatment of ischemic medical conditions. However, current methods to assess oxygen partial pressure in tissue suffer from a variety of disadvantages, including complex equipment and procedures that necessitate trained personnel. Additionally, the barrier function of the stratum corneum reduces oxygen exchange and can consequently hamper surface measurements of rapidly changing oxygen partial pressure in tissue. To overcome these challenges, a novel, easy-to-use technique to monitor the oxygen partial pressure in tissue using microneedle arrays (MNAs) has been developed. The MNAs can be made from poly(ethyl methacrylate) and poly(propyl methacrylate) and overcome the skin's barrier function to measure oxygen in the capillary bed and interstitial fluid of the skin. The MNAs' tips are embedded with an oxygen-sensitive phosphorescent metalloporphyrin, where the oxygen partial pressure inversely correlates to changes in both emission intensity and phosphorescence lifetime of the in-house developed red emitting Pt-core porphyrin. It was demonstrated that the oxygen-sensing MNAs are sufficiently robust to puncture human skin via rupture of the stratum corneum, and that the MNAs can detect changes in oxygen partial pressure in skin within the physiologically relevant range (0-160 mmHg). Additionally, the MNAs can be combined with a wearable wireless optical readout system, making these oxygen-sensing MNAs a novel wearable and portable method for user-friendly monitoring of oxygen partial pressure in skin.

Sensor-integrated wound dressings are emerging tools applicable to a wide variety of medical applications from emergency triage to at-home monitoring. Uncomfortable, unnecessary wound dressing changes may be avoided by providing quantitative insight into tissue characteristics related to wound healing such as tissue oxygenation, pH, and exudate/transudate volume. Here, a simple cost-effective methodology for quantifying oxygen and pH in a swellable hydrogel dressing using a single photograph is presented. The red and green luminescence of a novel dendritic polyamine Pt-porphyrin and fluorescein conjugate quantitatively responds to oxygen and pH, respectively, and enables robust sensing. The porphyrin conjugate, when combined with a four-arm star polyethylene glycol (PEG) amine polymer, rapidly crosslinks at room temperature with an N-hydroxysuccinimide (NHS)-PEG crosslinker to form a color-changing hydrogel dressing with tunable swelling capabilities applicable to a variety of wound environments. An inexpensive digital single-lens reflex (DSLR) camera modified with bandpass filters captures the hydrogel luminescence using simple macroscopic photography, and conversion to HSB colorspace allows for intensity-independent image analysis of the hydrogels' dual modality response. The hydrogel formulation exhibits a robust and validated visible red-orange-green "traffic light" spectrum in response to oxygen changes, regardless of swelling state, pH, or autofluorescence from skin, thereby enabling the clinician friendly naked-eye feedback., (© 2022 Wiley-VCH GmbH.)

Wearable devices have found widespread applications in recent years as both medical devices as well as consumer electronics for sports and health tracking. A metric of health that is often overlooked in currently available technology is the direct measurement of molecular oxygen in living tissue, a key component in cellular energy production. Here, we report on the development of a wireless wearable prototype for transcutaneous oxygenation monitoring based on quantifying the oxygen-dependent phosphorescence of a metalloporphyrin embedded within a highly breathable oxygen sensing film. The device is completely self-contained, weighs under 30 grams, performs on-board signal analysis, and can communicate with computers or smartphones. The wearable measures tissue oxygenation at the skin surface by detecting the lifetime and intensity of phosphorescence, which undergoes quenching in the presence of oxygen. As well as being insensitive to motion artifacts, it offers robust and reliable measurements even in variable atmospheric conditions related to temperature and humidity. Preliminary in vivo testing in a porcine ischemia model shows that the wearable is highly sensitive to changes in tissue oxygenation in the physiological range upon inducing a decrease in limb perfusion., Competing Interests: The authors declare no conflicts of interest., (© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.)

Skin burns are a significant source of injury in both military and civilian sectors. They are especially problematic in low resource environments where non-fatal injuries can lead to high morbidity rates, prolonged hospitalization, and disability. These multifaceted wounds can be highly complex and must be quickly diagnosed and treated to achieve optimal outcomes. When the appropriate resources are available, the current gold standard for assessing skin burns is through tissue punch biopsies followed by histological analysis. Apart from being invasive, costly, and time-consuming, this method can suffer from heterogeneous sampling errors when interrogating large burn areas. Here we present a practical method for the early visualization of skin burn severity using a topically applied fluorescein-loaded liquid bandage and an unmodified commercial digital camera. Quantitative linear mixed effects models of color images from a four day porcine burn study demonstrate that colorimetric changes within the HSB colorspace can be used to estimate burn depth severity immediately after burning. The finding was verified using fluorescence imaging, tissue cross-sectioning, and histopathology. This low-cost, rapid, and non-invasive color analysis approach demonstrates the potential of dye-loaded liquid bandages as a method for skin burn assessment in settings such as emergency medicine triage and low resource environments.

Quantification of tissue oxygen partial pressure (pO 2 ) at the skin surface is crucial for diagnostic applications in burns, reconstructive surgeries, diabetic ulcers, etc. Further, current advances in wearable and communications technologies have widened the use of transcutaneous oxygen monitors (TCOM) for home care or even enhance athletic performance. For TCOM technology to find widespread use, devices must function reliably yet independently of changes in environmental conditions, humidity in particular. To this end, we have explored the incorporation of an oxygen-sensing metalloporphyrin within different host matrix materials of different compositions with the goal of overcoming the humidity sensitivity of previously explored oxygen-sensing materials. We developed a tetraethyl orthosilicate (TEOS)-based, highly breathable, oxygen-sensing metalloporphyrin polymer film which responds to changes in oxygenation independent of humidity., (© 2019 American Society for Photobiology.)

A microfluidic device utilizing magnetically activated nickel (Ni) micropads has been developed for controlled localization of plasmonic core-shell magnetic nanoparticles, specifically for surface enhanced Raman spectroscopy (SERS) applications. Magnetic microfluidics allows for automated washing steps, provides a means for easy reagent packaging, allows for chip reusability, and can even be used to facilitate on-chip mixing and filtration towards full automation of biological sample processing and analysis. Milliliter volumes of gold-coated 175-nm silica encapsulated iron oxide nanoparticles were pumped into a microchannel and allowed to magnetically concentrate down into 7.5 nl volumes over nano-thick lithographically defined Ni micropads. This controlled aggregation of core-shell magnetic nanoparticles by an externally applied magnetic field not only enhances the SERS detection limit within the newly defined nanowells but also generates a more uniform (∼92%) distribution of the SERS signal when compared to random mechanical aggregation. The microfluidic flow rate and the direction and strength of the magnetic field determined the overall capture efficiency of the magneto-fluidic nanoparticle trapping platform. It was found that a 5  μ l/min flow rate using an attractive magnetic field provided by 1 × 2 cm neodymium permanent magnets could capture over 90% of the magnetic core-shell nanoparticles across five Ni micropads. It was also observed that the intensity of the SERS signal for this setup was 10-fold higher than any other flow rate and magnetic field configurations tested. The magnetic concentration of the ferric core-shell nanoparticles causes the SERS signal to reach the steady state within 30 min can be reversed by simply removing the chip from the magnet housing and sonicating the retained particles from the outlet channel. Additionally, each magneto-fluidic can be reused without noticeable damage to the micropads up to three times.

The University of Georgia maintains two meat-type chicken control strains: the Athens Random Bred (ARB) and the Athens Canadian Random Bred (ACRB). The Athens Random Bred was developed from colored plumage commercial meat chicken strains in 1956. The ACRB is a replicate population of the Ottawa Meat Control strain which was developed in 1955 from white plumage commercial meat-type chickens. These genetic lines have been extremely valuable research resources and have been used extensively to provide comparative context to modern meat-type strains. The ACRB may be the oldest pedigreed control commercial meat-type chicken still in existence today. This paper reviews the history of the breed backgrounds for both control populations and reviews research utilizing the ACRB., (© 2016 Poultry Science Association Inc.)

Surface-enhanced Raman scattering (SERS) optical nanoprobes offer a number of advantages for ultrasensitive analyte detection. These functionalized colloidal nanoparticles are a multifunctional assay component. providing a platform for conjugation to spectral tags, stabilizing polymers, and biorecognition elements such as aptamers or antibodies. We demonstrate the design and characterization of a SERS-active nanoprobe and investigate the nanoparticles' biorecognition capabilities for use in a competitive binding assay. Specifically, the nanoprobe is designed for the quantification of bisphenol A (BPA) levels in the blood after human exposure to the toxin in food and beverage plastic packaging. The nanoprobes demonstrated specific affinity to a BPA aptamer with a dissociation constant Kd of 54 nM, and provided a dose-dependent SERS spectra with a limit of detection of 3 nM. Our conjugation approach shows the versatility of colloidal nanoparticles in assay development, acting as detectable spectral tagging elements and biologically active ligands concurrently.

Patterns of early embryonic development have traditionally been viewed as invariant within vertebrate taxa. It has been argued that the specific differences which are found arise during the later stages of development. These differences may be a result of allometry, heterochrony or changes in relative growth rates. To test whether early embryonic development is indeed invariant, or whether selection of adult characteristics can alter embryonic growth, we compared embryonic development in birds selected for different patterns of postnatal growth. Using quail lines selected for high and low body mass, we compared somite formation, and muscle and feather development. We obtained data that showed changes in the rate of myotome formation in the brachial somites which contribute to muscle formation in the limbs and thorax. We think these observations are connected with intraspecific changes in adult morphology, ie., breast muscle size. Our findings suggest that selection for late ontogenetic/adult stages affects early embryonic development.

A line of Japanese quail selected for high plasma cholesterol is highly susceptible to diet-induced atherosclerosis. Lymphocyte epitopes recognized by mouse anti-chicken monoclonal antibodies (c-mAb), TCR-1, TCR-2, TCR-3. CD-3, CD-4, CD-8, and BU-1a/b were reacted with spleens from quail selected for high (HL) and low (LL) plasma total cholesterol and their nonselected controls (CL). Cross reactivity to c-mAb and effect of line and gender were immunohistochemically evaluated. Chicken spleens were positive controls. Quail were immunologically stimulated with either sheep red blood cells (SRBC) or Brucella abortus 2 weeks before spleens were removed. Quail spleen epitopes of all lines recognized TCR-3 and CD-8 c-mAb, but no other c-mAb. Number of reacting cells and staining intensity to the TCR-3 c-mAb were greater in the HL than in the LL regardless of the stimulating Ag or dose used. For the CD-8 c-mAb, there were no differences among lines in birds receiving SRBC. In B. abortus-immunized birds, sex x line interactions indicated that males of the HL and CL had lower responses than females but LL males were not different than females. TCR-3 and CD8 c-mAb may be useful in studying immunological mechanisms for atherosclerosis in Japanese quail.

The proportions of plasma high and low density lipoprotein cholesterol have been linked to inherited tendency for atherosclerosis in humans. Studies were conducted with Japanese quail males from lines genetically selected for high and low TC and a randombred (unselected) control line that were fed 0.0 or 0.5% cholesterol for 12 weeks. Atherosclerotic plaques were more severe in the high than in the low line quail and in those fed cholesterol compared to non-cholesterol-fed quail. Serum TG, TC, VLDLC, LDLC, and HDLC were also higher in the high than in the low line quail and in cholesterol-fed vs. non-cholesterol-fed quail. Significant interactions indicated that TC and LDLC concentrations were more affected by dietary cholesterol in the high line than in the low line. The low line quail maintained higher HDLC and lower LDLC than the high line. Regression and correlation analyses revealed that although VLDLC, LDLC, and TC were significant predictors of atherosclerosis in the high line birds, the TC/HDLC ratio was a better predictor in the low line. The Japanese quail lines used herein represent useful experimental models for studies of genetic differences in atherosclerosis in humans.

Dietary cholesterol metabolism was studied, using a single dose of emulsion, per os (test meal), in lines of Japanese quail that were divergently selected for high (HL) and low (LL) plasma total cholesterol. The meal contained [3H] cholesterol, [14C] beta-sitosterol, unlabeled cholesterol, triolein, and bile salt. Recovery of the nonabsorbable beta-sitosterol in the excreta permitted determination of the percentage of cholesterol absorbed. The amounts of [3H] in the plasma, egg yolks, and the excreta neutral and acid sterols were determined. A line-x-time interaction for [3H] in plasma indicated that the level of plasma cholesterol derived from the test meal declined more rapidly in the LL than in the HL. The higher [3H] detected in the excreta acidic sterols of the LL 12 hr after the test meal indicated that bile acid excretion of cholesterol was greater in the LL than in the HL. There were no differences in cholesterol absorption between lines or sexes. Cumulative [3H] radioactivity in the eggs over 18 days following the test meal was higher in the HL yolks; however, this line effect was due to the greater number of eggs produced by the HL. Thus, one of the mechanisms by which the LL maintains low plasma cholesterol levels is by an enhanced excretion of bile acid compared with the HL. The data also suggest that the more severe atherogenic effect of dietary cholesterol observed in the HL could be, in part, due to the longer residence time of cholesterol in circulation.

Long-term selection was conducted for high 4-wk BW in Japanese quail under different selection environments to investigate selection limits and to determine whether genetic parameters for growth are similar to those in chickens. Quail lines were selected under an adequate 28% CP diet (P line) and under a low 20% CP diet (T line). Mean realized heritabilities ranged from 0.32 (T line) to 0.49 (P line) during the first 10 generations. Although genetic variation remained following 97 generations of selection, realized heritabilities obtained agreed with theoretical predictions of loss of additive genetic variability with continuous selection. Similarity of heritability estimates indicates that Japanese quail are an excellent model for genetic studies of growth in meat-type chickens. Positive relationships accompanying selection for high 4-wk BW were increases in adult BW, age at first egg, and egg weight. Negative relationships were decreases in percentage fertility and hatchability, and egg production. Increased growth rate in selected lines was accompanied by an increase in feed and water intake, and by improvement in feed efficiency. Feed efficiency differences appeared to be important only immediately following hatch, whereas feed intake differences were present from 0 to 4 wk. Evidence of major physiological changes accompanying selection for growth were not observed. However, changes were observed in increased "resource allocations" to supply organs, during late embryonic stages and the 1st wk posthatch. Carcass composition was similar between unselected and selected lines except for higher fat and lower moisture levels in selected lines.

Japanese quail have been utilized as a research animal to establish genetic relationships that may be present in other poultry species. In this presentation, short-term selection experiments were reviewed. Selection intensity appeared to be the most effective in improving BW when selection experiments were compared on a response per generation basis; however, when generation interval was reduced, the response per year was superior despite lower selection intensities for lines selected the same number of generations. Correlated responses over 30 generations of divergent selection for 4-wk BW indicated that selection had a negative effect on fitness traits, including egg number and fertility. Traits such as follicle and egg weight and BW at the beginning of and after a 120-d laying period were positively correlated with BW during the growth period. The early response of quail lines selected for increased BW at 10, 17, 28, and 40 d of age indicate that the later selection is applied the greater the selection response at maturity. In fact, lines selected at young ages were competitive with late-selected lines only to the point at which selection occurred.

Japanese quail from lines that had been divergently selected for high (HL) or low (LL) plasma total cholesterol and their unselected control line (CL) were fed an all vegetable diet to which 0 or 0.5% crystalline cholesterol were added. Relationships between plasma and yolk cholesterol fractions were examined at 10, 14, and 18 wk of age, which followed 2, 6, and 10 wk consumption of the cholesterol-enriched diet, respectively. Unesterified cholesterol (UC) and cholesteryl esters (CE) in plasma and yolk were analyzed using HPLC. There were no consistent correlations between yolk and plasma for UC, individual CE, total esterified cholesterol (EC), or total cholesterol in the selected lines at ages tested, whether or not 0.5% cholesterol was added to the diet. Cholesterol concentrations in milligrams per gram of yolk and in milligrams per yolk were higher in the HL than the LL at 10 and 14, but not at 18 wk of age. Yolk weights of the HL females increased from 10 to 18 wk of age, whereas those of the LL did not. Cholesterol concentrations in the LL yolks continued to increase over time, however the increases in yolk weight in the HL were not accompanied by proportional increases in cholesterol deposition in the yolk, leading to a dilution of concentration of cholesterol fractions in the HL yolk. Dietary cholesterol increased egg production rate in the selected lines but did not increase the cholesterol content of the yolk.

A technique was developed to assess the number of cock spermatozoa penetrating the perivitelline layer (PL) in oviposited eggs in vivo. Two trials were conducted to test this technique and to establish correlation values between fertility and sperm penetration (SP). First, three Athens Canadian Randombred males, previously tested as having high fertility (100%), were each housed with seven hens. Sperm penetration was determined from eggs laid over a 3-d period (n = 41) with the mean number of spermatozoa penetrating the PL overlying the germinal disc (GD; 1.35 mm2 area) and nongerminal disc (NGD) areas being 162.8 and 8.4, respectively. Following removal of the males, SP was monitored to establish its duration with an average of 4.6 eggs analyzed per male per day. Mean sperm penetration during this period declined from 167.0 to .2 and from 9.2 to 0 for the GD and NGD regions, respectively. The mean duration of SP was 15.7 and 11.3 d for the GD and NGD PL, respectively. The duration of fertility was also established to be 14.0 d. There was a positive correlation between sperm penetration of the GD PL and fertility from eggs laid by naturally mated hens (r = .89, P < .001). In the second trial, three groups (1, 2, or 3) of 16 hens (35 wk of age) each were artificially inseminated weekly for 4 consecutive wk with either 100, 50, or 25 million sperm/50 microL, respectively. Inseminations were repeated weekly for 12 consecutive wk. Mean values were obtained from each of three 4-wk periods and used as replicates. Mean SP values from the GD PL for Groups 1, 2, and 3 were 402, 19.5, and 14.1, with fertility values of 95.8, 92.4, and 83.3%, respectively. Each replicate mean was obtained from approximately 24 eggs per group per day postinsemination. A significant correlation between SP of the GD PL and fertility (r = .90, P < .001) was established using artificial insemination of hens.

Although nonadditive genetic variation is more important in crosses among laying stocks than among meat stocks, development of special sire and dam lines to control the release of primary lines results in broilers being the product of three- or four-way crosses. Therefore, nonadditive genetic effects are important in meat stocks because of opportunities to combine stocks that complement each other. Four experiments were conducted to investigate heterosis and overdominance arising from crossing Japanese quail lines originating from the same base population and selected long-term ( > 85 generations) for high 4-wk BW under different selection environments. The different selection environments were established by feeding different levels of CP (28 and 20%) and different levels of thiouracil (0 and.2%). Estimates of heterosis were high for hatch of total eggs ( > 25%) and liveability (12 to 47%), and low for hatch weight (2 to 4%). Overdominance estimates followed similar patterns but were of lower magnitude. Percentage heterosis estimates for BW were high at 1 wk (20 to 30%) and declined linearly to 5 to 10% at 4 wk when quail were fed 28 and 24% CP diets. Contrariwise, when fed low-CP (20%) diets, heterosis values were low initially and remained stable or increased across age. Data obtained from measuring feed intake and feed efficiency indicated that heterosis for BW was closely related to change in feed intake. Heterosis values for feed intake closely followed those for BW, including the decline across age. Conversely, heterosis appeared to be absent for feed efficiency, except at 1 wk. Similar to heterosis estimates, overdominance estimates were high initially and declined across age and were more clearly demonstrated under the 24 and 28% diets. It was concluded that considerable heterosis is present for BW in Japanese quail following the crossing of lines selected long-term for high BW, but that it is dependent on both environment (diet) and age.

Three lines of Japanese quail males, unselected controls (CL), high response (HL), and low response (LL) lines, selected for plasma total cholesterol for 18 generations, were fed all-plant source, nonatherogenic diets to which 0 or .5% cholesterol were added from 6 to 18 wk of age. Atherosclerotic scores (AS) of aorta of HL birds fed cholesterol were significantly higher than those of LL birds fed cholesterol. Scores of LL fed cholesterol were not higher than LL not fed cholesterol. Fatty infiltration of muscularis and foam cell disruption of elastic fibers were observed in HL males fed cholesterol. In a second experiment, males of the three lines were fed from 6 to 14 wk of age four plant source diets to which were added: 1) 10% glucose monohydrate (cerelose); 2) 10% cerelose + .1% cholesterol; 3) 4% corn oil; or 4) 4% coconut oil. All diets were calculated to be isocaloric and isonitrogenous. Overall, AS of HL and CL males were significantly higher than LL males, but there were no effects of diet for the 56-d feeding period.

Three lines of Japanese quail females, randombred controls (CL), high response (HL), and low response (LL) lines, selected for plasma total cholesterol for 18 generations, were fed all-plant-source, nonatherogenic diets to which 0 or .5% cholesterol were added from 6 to 18 wk of age. In all three lines, plasma cholesterol increased when cholesterol was fed; however, responses were greater in the HL than in the LL line, with CL intermediate. In a second experiment, females of the three lines were fed, from 6 to 14 wk of age, four isocaloric, isonitrogenous plant-source diets to which were added: 1) 10% glucose monohydrate (cerelose); 2) 10% cerelose + .1% cholesterol; 3) 4% corn oil; or 4) 4% coconut oil. Baseline data obtained before feeding experimental diets indicated that the HL had significantly higher plasma total, esterified (EC) and unesterified (UEC) cholesterol than LL and that nonovulating females had higher concentrations of esterified cholesterol than ovulating females. Diets used did not affect cholesterol fractions in the ovulating females, although there were significant differences among lines. Dietary cholesterol significantly increased the ratio of EC to UEC. Sclerotic lesion scores were higher in the HL than the LL birds and in birds fed the coconut oil diet.

A study was conducted to examine genetic parameters associated with selection for high 8-wk BW in normal and dwarf Athens Canadian randombreds under two nutritional environments (high protein and high energy) and to determine the influence of the selection diet on subsequent water to feed ratios and abdominal fat levels. High-protein lines (HP) received a diet containing 25% CP and 3,100 kcal ME/kg, whereas high-energy lines (HE) received a 22% CP diet containing 3,200 kcal ME/kg. Body weights, selection gains, selection differentials, and heritabilities were similar for normal HP and HE lines. There was evidence, however, that the realized heritability was greater in the HE than the HP dwarf line. Similar selection differentials indicate that this difference was apparently due to the expression of greater genetic variation in the HE dwarf line. Water intake, feed intake, water to feed ratio, and abdominal fat data for the four lines under "selection" and "reciprocal" environments differed between experiments. In Experiment 1, when fed the HE diet, normal birds selected under the HP environment had higher (P < .05) water to feed ratios and lower abdominal fat levels than contemporaries selected under the HE diet. However, these differences were not significant in Experiment 2.

Feed restriction (70% of ad libitum consumption) was carried out from 1 d after hatching until 44 d in a randombred quail line and until 28 d in a quail line selected for high 4-wk BW. Body weights of restricted quail were significantly lower than ad libitum controls during restriction. Two weeks after restriction ended, however, BW were no longer different. Mortalities were twice as high under restriction. Hatchability of eggs was not affected by restriction, but restricted quail of the selected line laid fewer double-yolk eggs than ad libitum controls.

Following 17 generations of divergent selection for 4-wk BW under split- (SD) and complete- (CD) diet environments, two sublines were established from high (H-SD and H-CD) BW lines. Subline H-SDG derived from the H-SD line was selected for BW gain from 2 to 4 wk under the SD environment, whereas Subline H-CDG derived from the H-CD line was similarly selected under the CD environment. These two sublines were maintained and reproduced simultaneously with H-SD, L-SD, H-CD, L-CD lines from Generation 18 through 30. The purpose of changing the selection criterion was to investigate genetic variation in BW gain independent of changes that occur immediately following hatch. Selection progress and heritabilities (approximately .3) in BW lines (H-SD, H-CD, and L-SD) were similar from Generation 18 through 30. However, progress and heritability (approximately .1) was not as great in the L-CD line. These responses indicate that considerable additive genetic variation for 4-wk BW remains in these lines. Selection for increased BW gain from 2 to 4 wk in both sublines (H-SDG and H-CDG) resulted in smaller BW at 2 wk of age than did selection for 4-wk BW. Under the SD environment, H-SDG quail were smaller at 4 wk than H-SD quail following 12 generations of selection, whereas under the CD environment, H-CDG quail were larger than H-CD quail. Results indicate that selection for BW gain was more effective under the CD than SD environment and that the lack of improvement in 2-wk BW accompanying the increase in BW gain may adversely influence the potential benefits obtainable from selection for gain.

Four experiments were conducted to investigate feed and water intake, feed efficiency, and abdominal fat levels of six lines of chickens developed from two randombred control populations following selection for high 8-wk BW under high (1.6%), low (.2%), and normal (.4%) dietary salt selection environments. The Athens-Canadian Randombreds (AC) and Athens Randombreds (ARB) served as base populations for development of the six lines. Progeny from these lines were evaluated in the first, fifth, sixth, and seventh generations in Experiments 1, 2, 3, and 4, respectively. In Experiment 1, abdominal fat levels were shown to be inversely related to dietary salt level. The lowest abdominal fat level was observed in birds fed the 1.6% salt diet and the highest abdominal fat level in birds fed the .2% salt diet. Birds receiving the normal (.4%) salt diet had intermediate abdominal fat levels. In Experiments 2, 3, and 4, selected lines were exposed to different dietary salt levels to measure both line and dietary salt response patterns. Significant (P < .05) differences were observed between genotypes (AC vs ARB) and between dietary salt treatments for BW, feed and water intake, and water to feed ratio. However, there was no evidence of genetic change between lines in abdominal fat level as a result of selection under different salt environments.

A study was conducted to investigate the response to selection for 8-wk BW under selection environments that utilized different dietary salt levels to alter water to feed ratios. The Athens-Canadian (AC) and Athens Randombreds (ARB) served as base populations. A broiler diet consisting of 23% CP and 3,120 kcal of ME/kg was modified to contain .2, .4, and 1.6% dietary salt. Chicks from the AC and ARB populations were divided within full-sib families into three groups, with one group assigned to each of the three dietary salt selection environments. Individual phenotypic selection was conducted within the six lines for high 8-wk BW for six generations with unselected randombred controls included in each generation to measure environmental variation. No differences in 8-wk BW were observed among the three salt selection environments. Lines derived from the ARB population were initially approximately 75 g larger than those derived from the AC population. However, when BW were expressed as percentage deviation from the control in the sixth generation, selection response patterns were similar (AC lines, 28 to 32%; ARB lines, 32 to 36%). These data indicated that selection for 8-wk BW was as effective under high- and low-salt diets as under a normal-salt diet. Realized heritabilities, following correction for environmental variation, ranged from .38 to .46. Failure to correct for environmental variation resulted in large fluctuations in heritabilities across generations. These data provide strong support for inclusion of controls to accurately measure the heritability of BW in selection studies.

For 36 generations, 8-wk body weight was measured in Athens-Canadian Randombred males and females reared at the Southern Regional Poultry Genetics Laboratory (SRPGL) and at Virginia Polytechnic Institute and State University. Regressions of this trait on generations ranged from -.7 g for females reared in Virginia to -2.6 g for males reared at the SRPGL. Chickens were consistently heavier at the SRPGL, where a broiler diet was fed, than at Virginia, where the diet was considerably lower in protein and energy. Highly significant (P < or = .01) location by generation interactions reflected fluctuations at one location that were independent of those at the other location. Correlations between body weight at the two locations increased when chicks were vaccinated for Marek's disease.

Sex-linked dwarfism in chickens is a form of GH resistance that resembles the Laron syndrome in humans. The dwarfism found in chickens is due to a mutant gene (dw) carried on the sex chromosome. The homozygous dwarf (dwdw) chicken is characterized by reductions in stature and plasma insulin-like growth factor-I (IGF-I) levels. Despite the absence of hepatic GH-binding activity, Southern blot analysis shows that there is no gross structural change in the gene for the GH receptor (GHR) in this strain of dwdw chicken. GH-dependent IGF-I production can be restored in cultured dwdw hepatocytes after transfection and transient expression of a chicken GHR (cGHR) cDNA, indicating that other factors that participate in GH-mediated IGF-I synthesis are intact. Northern blot analysis of liver, muscle, fat, and pituitary RNA from normal (DwDw) chickens shows a major transcript of 4.3 kilobases (kb) and three minor transcripts (0.8, 1.7, and 3.2 kb), which correspond to the cGHR. In contrast, the 0.8-kb transcript is the major cGHR transcript expressed in these tissues from dwdw chickens. Northern blot analysis with domain-specific probes shows that the 0.8-kb transcript in DwDw and dwdw liver contains only a small portion of the extracellular domain of the cGHR. A cDNA clone encoding this transcript has been isolated from a liver library prepared from a normal chicken.(ABSTRACT TRUNCATED AT 250 WORDS)

This study investigated genetic variation in growth and final size in relationship to differences in heritabilities under good and poor feeding conditions. Heritabilities of growth and final size were estimated for several traits under ad libitum and restricted feeding conditions. A 30% feed restriction from hatching to 44 days of age in Japanese quail chicks decreased body weight and tarsus length at 44 days of age and the length of the third primary convert feather at 24 days of age relative to controls fed ad libitum. Wing length at 44 days of age was not significantly different for ad libitum fed and restricted quail. Genetic variances for body weight and tarsus length were very large throughout growth which resulted in heritability estimates close to one for these traits. The genetic correlations among feeding treatments were low, indicating that different genes were affecting growth under the two treatments. Growth was described by the components: asymptote, growth period, and shape of the growth curve following the modified Richards growth curve model (Brisbin et al. 1986). Tarsus length, which had high heritability of the parameter 'growth period' of the model, tended to display a higher heritability under the restriction than under ad libitum feeding. Body weight and feather length, which had either no heritable or low heritable 'growth periods' estimates, tended to be more heritable under ad libitum feeding. The shape parameter of the growth curve was not heritable for any trait, except tarsus length under restricted feeding.

Growth patterns of quail lines divergently selected for 4-wk BW under split and complete nutrition environments were investigated utilizing a diallel mating scheme. The design, involving 16 mating combinations, allowed investigation of heterotic effects, reciprocal cross effects, and combining ability. Progeny from Generation 27 breeders were evaluated in two hatches under both selection diets. Heterosis for hatch weight was essentially zero; however, percentage heterosis from High x High crosses and Low x Low crosses ranged from 5 to 18% after 1 wk of age. Quail progeny from Low x High crosses were consistently larger than quail from reciprocal High x Low crosses under both selection diets. Reciprocal differences were greatest immediately posthatch and declined with age. However, in crosses involving males from High and Low split diet lines mated to females from High and Low complete diet lines, large reciprocal differences in BW remained at 8 wk. Mean heterosis values for BW across ages from crossing High and Low lines both within and across selection environments were negative in six of eight comparisons. Mean values ranged from +3 to -11% and indicated that greater selection responses may have been made in divergent selection for low 4-wk BW than for high BW. General combining ability of lines was greater when transmitted via females as opposed to males, and was similar under the two diets (split and complete). There was evidence that high-BW lines exhibited greater general combining ability under both dietary environments than did low-BW lines.

A study was conducted to determine BW, feed intake, feed efficiency, and carcass composition changes following 51 generations of selection for high 4-wk BW in Japanese quail. Quail lines utilized were the P line selected for high 4-wk BW on a normal 28% CP diet and the unselected base population (C line) from which the P line originated. Body weight, feed intake, and feed efficiency data were collected daily from 1 to 28 days, whereas percentage carcass water, ash, protein, and total lipid data were obtained at 0, 4, 7, 10, 14, 21, 28, 42, and 56 days of age. Body weights of P line quail were significantly (P < .05) larger than BW of C line quail at all ages with the greatest deviation occurring at the age of selection. Feed intake was significantly greater in the P line and paralleled BW increases. When feed intake was adjusted for differences in BW, P line quail consumed less feed per gram of BW than C line quail and adjusted feed intake declined with age after Week 1. The P line quail had superior feed efficiency compared with C line quail from 1 to 13 days of age with the greatest deviation immediately posthatch. Carcass composition determinations revealed significant (P < .05) age and line effects. Both percentage ash and protein increased from hatch to 14 days and thereafter remained constant. However, percentage water and total lipid demonstrated contrasting responses to increasing age; percentage water declined whereas percentage total lipid increased. The P line quail had less carcass water and protein, but had more lipid.(ABSTRACT TRUNCATED AT 250 WORDS)

Two experiments were conducted to determine the protein requirement of quail lines (P and T) following selection for increased 4-wk BW under normal-protein (28% CP) and low-protein (20% CP) diets, respectively. Quail progeny from Generation 39 breeders were fed diets containing 18, 21, 24, and 27% CP from 0 to 5 wk of age in Experiment 1, whereas in Experiment 2, quail progeny from Generation 79 breeders were fed diets containing 18, 21, 24, 27, and 30% CP from 0 to 4 wk of age. Quail from the unselected base population (C line) were also included in both experiments. Significant line, diet, and line by diet interactions were present in both experiments. At 2 wk of age, T line quail were significantly (P < .05) larger than P line quail across diets, whereas by 4 wk, BW of P line quail were significantly larger than those of T line quail. Across dietary protein levels, quail receiving diets containing 24% CP or higher were significantly larger than those receiving the 18 and 21% CP diets. Quail in both the P and C lines had larger BW with increasing protein levels and an apparent protein requirement between 24 and 27% CP. However, quail in the T line showed no BW response to increased protein levels, indicating that long-term selection for increased BW on a 20% CP diet had altered the protein requirement in this line.(ABSTRACT TRUNCATED AT 250 WORDS)

A myofiber hyperplastic quail line P has been developed through selection for heavy body weight. Since the number of muscle fibers is determined early in development and skeletal muscle originates from somites, we compared somite formation and muscle-specific gene expression in P- and control C-line quail embryos. At 47 hours of incubation, C embryos had 18 somite pairs and P embryos had 14.3. By 72 and 120 hours, both lines appeared to be at the same stage of somite development. To determine whether the delay in the formation of the brachial somites was accompanied by alterations in muscle-specific gene expression, we conducted whole-mount in situ hybridization and immunofluorescence studies. At 47 hours of incubation, C embryos were expressing qmf1 in the first 12 somites, while in P embryos only the first 7 somites showed qmf1 activation. Delays in expression were also observed for qmf3 at 43 hours and for all three myogenic factors (qmf1, qmf2 and qmf3) at 60 hours. At 65 hours, C embryos expressed myosin heavy chain in the first 15 somite pairs and P embryos in the first 7. At 72 hours, the transient delay in somite formation had disappeared and there was no lag in myosin heavy chain expression between the lines. The phase delay in brachial somite formation, myogenic factors and myosin heavy chain expression may be associated with the observed myofiber hyperplasia in P-line quail by allowing an increase in the muscle stem cell population.

Line by sex interactions of BW, abdominal fat, testes weight, and plasma cholesterol were investigated in two Japanese quail lines. High (H-PCHOL) and low (L-PCHOL) quail lines had been developed by 18 generations of divergent selection for plasma cholesterol response to adrenocorticotropin (ACTH). Quail were from Generation 28 breeders maintained under a normal environment with no exposure to exogenous ACTH after Generation 18. Quail from growth-selected lines were also used to examine relationships between BW and plasma cholesterol. Body weights of H-PCHOL quail were significantly (P less than or equal to .05) heavier than BW of L-PCHOL quail at 2 and 4 wk of age. However, at 8, 16, and 28 wk BW were similar. Quail from long-term, growth-selected lines were observed to have plasma cholesterol levels similar to those of control lines. Therefore, early BW changes in H-PCHOL and L-PCHOL lines may not be related to plasma cholesterol changes. At 2 and 4 wk, male and female plasma cholesterol values were similar in the H-PCHOL and L-PCHOL lines, however, at 8 and 16 wk males had higher values than females in the H-PCHOL line, and females had higher values than males in the L-PCHOL line. Because interactions were present only after sexual maturity was reached, sex hormones may be involved in the expression of these interactions. Quail in the L-PCHOL line were observed to have significantly (P less than or equal to .05) more abdominal fat and significantly (P less than or equal to .05) smaller testes than quail in the H-PCHOL line.

Data are presented on the pattern of organ growth in embryos from a line of Japanese quail selected for high growth rate and compared with those from a non-selected control line. The data reveal that the increased growth rate post hatching is accompanied by a more rapid early development of the digestive organs. It appears from these results that the "genes for" growth rate are the "genes for" early growth of the digestive organs.

Decreased hatchability in Japanese quail following selection for growth and relative improvements in hatchability following selection during goitrogen treatment were investigated. An unselected quail line (Line C) and lines selected for high 4-wk body weight while being fed diets containing either 20% CP and .2% thiouracil (TU) (Line T), or 28% CP and no TU (Lines P and H-CD) were used. Egg weight loss between 0 and 4, and 0 and 14 days of incubation, hatchability, and developmental stage of embryonic mortalities were determined in Experiment 1. Length of the incubation period, and percentages of body water and dry body weight were determined for 10- and 14-day embryos and 18-day-old chicks in Experiment 2. Eggshell quality was determined in Experiment 3. Hatchability was lower in selected than in unselected quail due to increased early and late embryonic mortality. Egg weight loss during incubation was greater in Line P than in Line C eggs. Weight loss, measured across lines, was lower in eggs that hatched than in those in which embryos died early. Percentage body water was higher in Line C than in Lines P and T at 14 and 18 days of incubation; however, percentage body water in Line T was lower than Line P at 14 days. Percentage of dry body weight was greater in Lines P and T than in Line C at 14 and 18 days. Eggshell thickness was greater in Line H-CD when compared with Line C. Increases in eggshell permeability occurring during selection for growth were associated with increased embryonic mortality and decreased hatchability.(ABSTRACT TRUNCATED AT 250 WORDS)

High (H) and low (L) quail lines divergently selected for 4-wk BW under complete-diet (CD) and split-diet (SD) environments were evaluated to examine changes in feed intake and feed efficiency before and after the age at selection. Progeny from the four quail lines (H-SD, L-SD, H-CD, L-CD) were fed the CD in Generation 17 and the SD in Generation 19. The BW of H-line quail were highest under their respective selection environments, and the BW of quail in the L lines were highest under reciprocal environments. However, the BW of the two H lines were similar as were those of the two L lines. Relative growth rates of H-line quail were superior to those of L-line quail for the first 2 wk posthatch but L-line rates were superior after Week 4. However, the BW of H-line birds were always higher than for the L-line birds. Adjusted feed intake (grams of feed per 100 g of BW) values for the H lines were similar but lower than values for the L lines. Differences in adjusted feed intake between the H and L lines from 1 to 10 wk remained constant, although adjusted feed intake declined with age in all lines. Feed efficiencies (grams of gain divided by grams of feed) were superior in the H lines for Weeks 1 through 3 and superior in the L lines for Weeks 5 through 9. The same relative shifts between lines were observed in relative growth rates. Therefore, feed efficiency, in addition to feed intake, appears to play an important role in the divergence of BW in the H- and L-quail lines.

Studies were conducted to determine the effect of divergent selection for plasma cholesterol response to adrenocorticotropin (ACTH) on the levels and relationships between plasma and yolk cholesterol in Japanese quail. Cholesterol data were obtained in Generation 25, following seven generations of relaxed selection, from birds maintained under a normal environment with no exposure to exogenous ACTH. Levels of plasma and yolk cholesterol were determined at 22 and 28 wk. Plasma cholesterol levels of quail in the low cholesterol line were significantly (P less than .01) lower than levels in the high line at both ages (224 versus 383 and 209 versus 326 mg/100 mL, respectively). In contrast, yolk cholesterol levels were significantly (P less than .01) higher in the low line than in the high line (24.1 versus 21.5 and 21.1 versus 16.9 mg cholesterol/g yolk at 22 and 28 wk, respectively). A significant line by sex interaction was present at both ages for plasma cholesterol with females having higher cholesterol values than males in the low line and males having higher values than females in the high line. A negative relationship was observed between changes in plasma and yolk cholesterol in the selected lines. Greater deposition of cholesterol in the yolk of the line with lower plasma cholesterol indicates that excretion rate may play a role in explaining genetic differences in plasma cholesterol.

Divergent selection during Generations 12 to 20 for high (H) and low (L) 4-wk BW under split-(SD) and complete-(CD) diet environments resulted in continued progress in both upward and downward directions. Following 20 generations of selection, there were 4.8- and 3.6-fold differences between BW of H and L lines in the SD and CD environments, respectively. Regression coefficients of mean 4-wk BW on generation of 1.88 and 1.58 g in the H lines and -1.50 and -1.37 g in the L lines indicated symmetrical selection responses. Realized heritabilities for 4-wk BW ranged from .2 to .4; selection differentials were significantly (P less than .01) larger in the H lines than in the L lines. Directional changes in 2-wk and adult BW and in egg weight across generations were similar to that of the selection trait (4-wk BW). Selection resulted in decreased hatchability and egg production and an increase in the age of sexual maturity. However, these changes were smaller than corresponding changes observed in earlier generations (0 to 11). Egg size of lines selected in the SD environment continued to be larger than egg size of corresponding lines in the CD environment. Considerable genetic variation for BW remains under both SD and CD environments following 20 generations of divergent selection. Smaller gains resulting from lower heritabilities agree with theoretical expectations of decreasing responses accompanying continuous selection.

Three experiments were conducted to measure changes in plasma thyroxine (T4) concentrations occurring in male and female Japanese quail in response to treatment with dietary thiouracil (TU) and different CP levels prior to sexual maturity and to determine the influence of selection for growth under TU and protein stress on this response. Selected and unselected lines of quail were fed diets containing .2% TU or two levels of CP (20 or 28%) or both from 0 to 4 wk of age. Body weight and plasma T4 were measured at 5, 7, and 9 wk of age in Experiments 1 and 2. In Experiment 3, body weight was measured at 2, 4, 5, 7, and 9 wk and T4 at 4, 7, and 9 wk. Thiouracil inhibited growth to a greater degree than did decreased dietary CP. However, offspring from selected quail were more resistant to dietary TU when selection diets contained TU. When fed as part of a selection regimen rather than to unselected birds, low CP, TU diets inhibited body weight increase to a greater degree and longer after birds were returned to control diets. Thyroxine concentrations between 4 and 9 wk were affected by TU but not by CP level. Thiouracil significantly reduced T4 during treatment; however, T4 was elevated by 3 wk after cessation of TU treatment. Increases in T4 were greater and more immediate in selected than in unselected birds. These findings reveal the ability of quail to compensate for thyroid suppression after TU is removed from the diet and the influence of selection on this compensatory response.

The in vivo toxicity of aflatoxin and the in vitro microsomal metabolism of aflatoxin B1 (AFB1) were investigated in a population of chickens previously selected for resistance to aflatoxin (AR line) and a corresponding control population (NS line) after in vivo pretreatment with saline, sodium phenobarbital (PB), or beta-naphthoflavone (BNF) solutions. PB pretreatment increased survival and BNF pretreatment increased mortality in both the NS and AR lines when a single oral dose of aflatoxin was administered. The rate of in vitro metabolism of AFB1 was greater with microsomes from saline pretreated AR chicks than with microsomes from similarly treated NS chicks. In vivo pretreatment with PB increased AFB1 metabolism by NS and AR microsomes. After BNF pretreatment of vivo, AR microsomes metabolized more AFB1 than NS microsomes, and there was a dramatic decrease in AFB1 metabolism in NS microsomes. AFB1-dihydrodiol was the major metabolite produced by both lines, with aflatoxin M1 and aflatoxin Q1 recovered in small quantities from BNF-pretreated AR microsomal incubations only. These data indicate that increased in vivo resistance of the AR line to acute aflatoxicosis may be related to increased hepatic AFB1 metabolism and that genetic selection has resulted in altered in vitro quantitative and qualitative metabolism of AFB1 in the AR line.

Six experiments were conducted to investigate abdominal fat levels in mature male and female Japanese quail following selection for 4-wk body weight and to investigate the relationship between testes development and abdominal fat accumulation. The present study utilized P-, T-, and S-line quail selected for more than 75 generations for high 4-wk body weight and also lines divergently selected (16 or more generations) for high (H-SD, H-CD) and low (L-SD, L-CD) 4-wk body weight. Adult males had from two to four times more abdominal fat than females, the reciprocal of abdominal fat patterns in chickens. These differences were observed regardless of the selection environment, direction of selection, or duration of selection. Percentage of abdominal fat was higher in high body weight lines than in low body weight lines, and correlation coefficients between body weight and abdominal fat were moderate to high (mean = .39). Correlations between abdominal fat and testes weights were positive and largest at 5 wk (r = .62).

The resistance to a single oral dose (12 mg of aflatoxin per kg of BW) and 4 wk of dietary aflatoxin (2.5 mg per kg of feed) were investigated in chicks selected for five generations for resistance to acute aflatoxicosis (AR) and unselected control (C) chicks. The AR chicks were more resistant to a single oral dose of aflatoxin and had significantly decreased sodium pentobarbital sleeping time compared to C chicks. Four-weeks exposure to dietary aflatoxin did not result in any significant change in BW or feed conversion ratios of chicks from either the C or AR line. However, more sensitive indicators of aflatoxicosis including plasma total protein, albumin, cholesterol concentrations, and gamma glutamyl transferase activity were significantly altered in C chicks but not in AR chicks fed aflatoxin. Percentages of liver lipid and liver hyperplasia score were also significantly altered as a result of dietary aflatoxin treatment in C but not AR chicks. These data indicate that selection-associated differences exist between the C and AR lines of chickens that convey resistance to not only a single oral dose of aflatoxin but also to a more chronic dietary exposure to aflatoxin.

Japanese quail (Coturnix coturnix japonica) lines were divergently selected for plasma cholesterol response to adrenocorticotropin (ACTH). Data for Generations 9 to 18 indicated a greater response in the low (L) line than in the high (H) line, which was contrary to selection responses for the first eight generations. During Generations 9 to 18, selection differentials were greater in the H line; however, heritability estimates were greater in the L line. These data suggest caution in the interpretation of early selection responses for plasma cholesterol. Selection for plasma cholesterol response following ACTH injection also resulted in divergence in plasma cholesterol levels in the H and L lines in the absence of ACTH. Body weights at 31 days were greater in the H line than in the L line, suggesting a possible relationship with the plasma cholesterol level.

Two experiments were conducted to investigate feed intake and body weight of males restricted to the water intake of ad libitum females immediately after hatch. Ad libitum males were heavier and consumed more feed than ad libitum females, with differences becoming significant after Day 10. Body weight and feed intake of water-restricted males and females were essentially identical, suggesting that when males and females receive the same amount of water, they also consume similar amounts of feed. Ad libitum males tended to have higher feed efficiencies than females, whereas water-restricted males and females had similar feed efficiencies. These data indicate that unless males are able to consume more water than females, there is an absence of development of sexual dimorphism in body weight during early life.

The purpose of this study was to determine if the compositional and cellularity changes associated with selection for rapid growth rate in an optimal and suboptimal nutritional environment were similar. The P-line Japanese quail had undergone long-term selection for high 4-week body weight and received a 28% protein diet. The unselected C-line quail received the same diet. T-line quail were selected by the same criteria as P-line quail but received a 20% protein diet containing .2% thiouracil. Body weights and muscle weights of P- and T-line quail were similar at 10 days of age. At 56 days T-line body weight and muscle weights were intermediate between C- and P-line quail, but whole body composition of P- and T-line quail was similar. The P- and T-line quail possessed a greater apparent number of muscle fibers than C line quail. Total muscle DNA content was lower in T-line muscles compared to P-line muscles at 56 days of age. No differences within age were observed among lines of myofiber diameter, fiber type composition, for concentrations of DNA, RNA and protein, or for protein/DNA and RNA/DNA. At 10 days the weight, length and diameter of the humerus and femur bones were greatest in T-line quail; these same parameters were intermediate between C- and P-line quail at 28 and 56 days of age. It was concluded that selection for rapid growth rate per se caused apparent fiber number and fiber length to increase while the effect of suboptimal nutritional environment was not evident until after 10 days of age. Selection under suboptimal conditions as exercised in this study prevented expression of the maximum number of muscle DNA units.

Two experiments were conducted to investigate the possible relationship of water intake and water/feed ratios in explaining abdominal fat changes associated with changes in dietary protein level and diet form. In Experiment 1, day-old male chicks from two commercial broiler stocks were fed diets containing 26, 22, and 17% protein from 0 to 19 days of age. Chicks fed the 26% protein diet consumed more water, had higher water/feed ratios, and had less abdominal fat than chicks fed lower protein diets. Chicks fed the 22% protein diet were intermediate to the 26 and 17% protein treatments in water consumption, water/feed ratios, and abdominal fat. In Experiment 2, day-old male chicks from two commercial broiler stocks were fed a diet in either mash or crumbled form from 0 to 20 days of age. Chicks fed crumbles had heavier body weights, consumed more feed and water, and had more abdominal fat than birds fed the mash diet. Superior body weights of birds fed the crumbled diet appeared to be due to higher relative growth rates immediately after hatch.