Bitter taste elicits an aversive reaction, and is believed to protect against consuming poisons. Bitter molecules are detected by the Tas2r family of G-protein-coupled receptors, with a species-dependent number of subtypes. Chickens demonstrate bitter taste sensitivity despite having only three bitter taste receptors—ggTas2r1, ggTas2r2 and ggTas2r7. This minimalistic bitter taste system in chickens was used to determine relationships between in-vitro (measured in heterologous systems) and in-vivo (behavioral) detection thresholds. ggTas2r-selective ligands, nicotine (ggTas2r1), caffeine (ggTas2r2), erythromycin and (+)-catechin (ggTas2r7), and the Tas2r-promiscuous ligand quinine (all three ggTas2rs) were studied. Ligands of the same receptor had different in-vivo:in-vitro ratios, and the ggTas2r-promiscuous ligand did not exhibit lower in-vivo:in-vitro ratios than ggTas2r-selective ligands. In-vivo thresholds were similar or up to two orders of magnitude higher than the in-vitro ones.

In order to examine the differences in bone properties between fast-growing and slow-growing broiler embryos and to understand the effects of genotype and egg size on these differences, fast- and slow-growing hens and males were reciprocally crossed to create 4 egg groups: FST (laid by fast-growing hens, inseminated by fast-growing males), H-FST (fast-growing hens and slow-growing males), H-SLW (slow-growing hens and fast-growing males), and SLW (slow-growing hens and slow-growing males). Embryos (n = 8) from these 4 groups were sacrificed and weighed, and both tibiae were harvested on embryonic d (E) 17, 19, and 21. Left tibiae were tested for their whole-bone mechanical properties using a micromechanical device. Cortical bone structure and bone mineral density (BMD) were examined by micro-computed tomography of the left tibiae. Bone mineralization was evaluated by measuring BMD and ash content, while the rate and location of mineralization were evaluated by fluorochrome labeling. Osteoclastic activity and osteocyte density were evaluated by histological stains [TRAP (Tartrate resistant acid phosphatase) and H&E (Hematoxylin and Eosin), respectively]. Groups with larger eggs (FST and H-FST) had higher BW and tibia weight than groups with smaller eggs (SLW and H-SLW); however, they had a lower ratio of tibia weight to BW. Between groups with similar egg weight, stiffness, maximal load, and yield load of the bones were higher in the SLW than the H-SLW, while no differences were found between the FST and H-FST. Additionally, the tibiae of the SLW were stiffer and their osteocyte density higher than in the FST on E21 and their periosteal mineralization rate was higher between E19 and E21. No differences were found between the groups in cortical bone structure. This study demonstrates that faster growing hatchlings, especially those that hatch from relatively small eggs, have inferior bone mechanical properties in comparison to slower growing hatchlings, and suggests that fast-growing chicks hatching from small eggs are at a higher risk for developing bone pathologies. Accordingly, selection for increased egg size may lead to improved mechanical performance of the skeleton of fast-growing broilers.

The sense of taste has a key role in nutrient sensing and food intake in animals. A standardized and simple method for determination of tastant-detection thresholds is required for chemosensory research in poultry. We established a 24-h, 2-alternative, forced-choice solution-consumption method and applied it to measure detection thresholds for 3 G-protein-coupled receptor-mediated taste modalities—bitter, sweet, and umami—in chicken. Four parameters were used to determine a significant response: 1) tastant-solution consumption; 2) water (tasteless) consumption; 3) total consumption (tastant and water together); 4) ratio of tastant consumption to total consumption. Our results showed that assignment of the taste solutions and a water control to 2 bottles on random sides of the pen can be reliably used for broiler chicks, even though 47% of the chicks groups demonstrated a consistently preferred side. The detection thresholds for quinine (bitter), L-monosodium glutamate (MSG) (umami), and sucrose (sweet) were determined to be 0.3 mM, 300 mM, and 1 M, respectively. The threshold results for quinine were similar to those for humans and rodents, but the chicks were found to be less sensitive to sucrose and MSG. The described method is useful for studying detection thresholds for tastants that have the potential to affect feed and water consumption in chickens.

Histone variants and their chaperones are key regulators of eukaryotic transcription, and are critical for normal development. The histone variant H3.3 has been shown to play important roles in pluripotency and differentiation, and although its genome-wide patterns have been investigated, little is known about the role of its dynamic turnover in transcriptional regulation. To elucidate the role of H3.3 dynamics in embryonic stem cell (ESC) biology, we generated mouse ESC lines carrying a single copy of a doxycycline (Dox)-inducible HA-tagged version of H3.3 and monitored the rate of H3.3 incorporation by ChIP-seq at varying time points following Dox induction, before and after RA-induced differentiation. Comparing H3.3 turnover profiles in ESCs and RA-treated cells, we identified a hyperdynamic H3.3-containing nucleosome at the −1 position in promoters of genes expressed in ESCs. This dynamic nucleosome is restricted and shifted downstream into the +1 position following differentiation. We suggest that histone turnover dynamics provides an additional mechanism involved in expression regulation, and that a hyperdynamic −1 nucleosome marks promoters in ESCs. Our data provide evidence for regional regulation of H3.3 turnover in ESC promoters, and calls for testing, in high resolution, the dynamic behavior of additional histone variants and other structural chromatin proteins.

ABSTRACT Previous studies demonstrated that in ovo photostimulation with monochromatic green light increases body weight and accelerates muscle development in broilers. The mechanism in which in ovo photostimulation accelerates growth and muscle development is not clearly understood. The objective of the current study was to define development of the somatotropic axis in the broiler embryo associated with in ovo green light photostimulation. Two-hundred-forty fertile broiler eggs were divided into 2 groups. The first group was incubated under intermittent monochromatic green light using light-emitting diode (LED) lamps with an intensity of 0.1 W\m2 at shell level, and the second group was incubated under dark conditions and served as control. In ovo green light photostimulation increased plasma growth hormone (GH) and prolactin (PRL) levels, as well as hypothalamic growth hormone releasing hormone (GHRH), liver growth hormone receptor (GHR), and insulin-like growth factor-1 (IGF-1) mRNA levels. The in ovo photostimulation did not, however, increase embryo's body weight, breast muscle weight, or liver weight. The results of this study suggest that stimulation with monochromatic green light during incubation increases somatotropic axis expression, as well as plasma prolactin levels, during embryonic development.

Heterophil/lymphocyte (H/L ratio) statistics and total white blood cell counts (TWBC) determined by light microscopic examination of blood from isolator raised specific pathogen free (SPF) chicks indicated complex hemograms. Brachial vein blood (N =12) obtained at 6 wk was spread into films, air dried, post-fixed in MeOH and Wright’s stained. H/L 1 ratios were calculated by dividing all heterophil types, typical (HT) variant (HV) and classic (HC) by the number of small (resting) lymphocytes (Ls) H/L 1 = (HT + HV + HC)/(Ls). A second ratio (H/L 2) obtained by dividing heterophils by all lymphocytes (resting, reactive and atypical, (HT + HV + HC)/ (Ls + Lm) was calculated; as was the H/L 1-H/L 2 difference (ΔH/L). TWBC’s were determined from the same films. Sorting, non-random distribution of cells and atypia affected all H/L statistics. The mean H/L 1 ratio from standard differential counts (SDC) = 0.17 and H/L 2 = 0.16. Edge based ratios (EB) were  8 times the SDC values. Atypical cells were in all samples and more common in EB counts. The H/L ratios and ΔH/L calculated from SDC and EB values were significantly different (p<0.02). Collectively these observations support earlier conclusions regarding the lack of sensitivity of a single H/L ratio, without a TWBC, or consideration of atypia to estimate welfare. Furthermore, hemograms of SPF chickens reared in isolation may be complex. © Asian Network for Scientific Information, 2016.

Avian reovirus (ARV) is a disease-causing agent. The disease is prevented by vaccination with a genotype-specific vaccine while many variants of ARV exist in the field worldwide. Production of new attenuated vaccines is a long-term process and in the case of fast-mutating viruses, an impractical one. In the era of molecular biology, vaccines may be produced by using only the relevant protein for induction of neutralizing antibodies, enabling fast adjustment to the emergence of new genetic strains. Sigma C (SC) protein of ARV is a homotrimer that facilitates host-cell attachment and induce the production and secretion of neutralizing antibodies. The aim of this study was to identify the region of SC that will elicit a protective immune response. Full-length (residues 1-326) and two partial fragments of SC (residues 122-326 and 192-326) were produced in Escherichia coli. The SC fragment of residues 122-326 include the globular head, shaft and hinge domains, while eliminating intra-capsular region. This fragment induces significantly higher levels of anti-ARV antibodies than the shorter fragment or full length SC, which neutralized embryos infection by the virulent strain to a higher extent compared with the antibodies produced in response to the whole virus vaccine. Residues 122-326 fragment is assumed to be folded correctly, exposing linear as well as conformational epitopes that are identical to those of the native protein, while possibly excluding suppressor sequences. The results of this study may serve for the development of a recombinant subunit vaccine for ARV. © 2016 Elsevier Ltd.

The combined temperature-humidity heat stress is estimated in farm animals by indices derived of an index based on human thermal comfort sensation. The latter index consists of temperature and humidity measures that sum to form the temperature-humidity index (THI). The hitherto unknown relative contribution of temperature and humidity to the THI was examined. A temperature-humidity data set (temperature 20–42 °C and relative humidity 10–70 %) was used to assess by regression procedures the relative weights of temperature and humidity in the variance of THI values produced by six commonly used heat stress indices. The temperature (Ta) effect was predominant (0.82–0.95 of variance) and humidity accounted for only 0.05 to 0.12 of THI variance, half of the variance encountered in animal responses to variable humidity heat stress. Significant difference in THI values was found between indices in the relative weights of temperature and humidity. As in THI indices, temperature and humidity are expressed in different physical units, their sum has no physical attributes, and empirical evaluations assess THI relation to animal responses. A sensible heat THI was created, in which at higher temperatures humidity reaches 0.25 of sensible heat, similarly to evaporative heat loss span in heat stressed animals. It relates to ambient temperature-humidity similarly to present THI; its values are similar to other THI but greater at higher humidity. In warm conditions, mean animal responses are similar in both indices. The higher sensitivity to humidity makes this index preferable for warm-humid conditions. © 2016, ISB.

Due to increase in awareness of poultry welfare and concomitant legislation, it has become necessary to determine poultry's response to stress, with minimal harm and maximum reliability. Several methods to determine the response to physiological stress were developed throughout the years to identify stressors and to measure stress in poultry. The most commonly used are plasma corticosterone levels and peripheral blood heterophil/lymphocyte ratio (H/L ratio). However, the value of these responses to determine a state of stress has been questioned in several instances, as these parameters are increased during the process of bird handling and blood sampling irrespective of the general state of stress. Due to these limitations, it appears that the classic stress markers might be sub-optimal in evaluating stress in poultry, particularly those encountered in high-stress environments. Thus, there is a continuing need for stress indicators, preferably indicators that are quantitative, highly repeatable, not influenced by handling and sampling, determined in peripheral blood, represent an initial response to the stressor, and do not daily fluctuate. As the immune system has been shown to rapidly respond to stress, we assessed pro-inflammatory gene expression in peripheral blood cells as an indicator for stress. We initially show that while corticosterone plasma levels and the H/L ratio were responsive to handling and blood sampling, pro-inflammatory gene expression (lysozyme, IL-1β, IL-6, and HSP-70) was not. We then determined the expression of the same pro-inflammatory genes during acute stress (transit) in layer pullets (hen and turkey) and during chronic stress (different caging densities of layers utilizing 2, 3, and 4 hens/cage). While gene expression was significantly and highly elevated during transit, the effect of differing caging densities on gene expression was minimal; collectively, this might indicate that expression of pro-inflammatory genes is more responsive to acute stress than to chronic stressors. We propose to use pro-inflammatory gene expression in peripheral blood cells to measure responses to stress in poultry.

BackgroundFuran fatty acids (F-acids) are valuable minor fatty acids which are appraised for their protective role against lipid oxidation of polyunsaturated fatty acids (PUFAs). The most relevant dietary source for F-acids is fish with the predominant occurrence of up to five dimethyl- or monomethyl-substituted homologues. During the screening of fish from a zero discharge aquaculture (ZDA) system we noted the potential presence of unusual F-acids. Methods We developed a method by gas chromatography with mass spectrometry operated in the selected ion monitoring mode for elucidation of the structures of the uncommon F-acids. Results Carp from the ZDA system contained seven non-methylated F-acids with dominance of 8-(5-hexylfuran-2-yl)-octanoic acid (8F6). Non-methylated F-acids have never been detected before in fish. Subsequent analysis of other fish species and a batch of the fish feed confirmed the presence of non-methylated F-acids. Conclusions F-acids in fish are derived from the feed. Our investigation indicates that more emphasis should be put on the F-acid concentrations in fish from aquaculture, which appears to depend on the quality of the fish feed.

Reuse of grey water (GW) enables to reduce fresh water consumption, but a treatment is required to prevent potential transmission and propagation of pathogenic organisms. This study presents results on the removal of pathogenic bacteria from GW as well as reduction of turbidity, TSS COD, and BOD by a novel treatment system. Compared to previous studied methods, three new elements are presented in the current treatment of GW: (1) A granulated complex of micelles of the organic cation octadecyltrimethylammonium (ODTMA) with montmorillonite was employed in filtration of GW. This complex was efficient in purifying GW due to its large surface area, positive charge and existence of hydrophobic domains. The granulated complex enabled flow when present exclusively in the filter; (2). A moving bed reactor for decomposition of part of the organic matter in the GW. This pretreatment stage, prior to the micelle-clay filter, was also efficient in removing pathogenic bacteria; (3) A regeneration stage of the micelle-clay filter conducted by passing either dilute solutions of Na-hypochlorite or HCl through the micelle-clay complex, or by heating the complex. Incubation of GW for either two weeks or one day in the pretreatment stage yielded a 10- and 7-fold enhancement in the volume filtered, which did not contain fecal coliforms, i.e., 300 and 210L for 40g of complex, respectively. The capacity of purified volume per gram of the complex increased further several-fold (>23L/g) for filters filled exclusively with granules. Regeneration of the complex in the filter further enhanced the capacity.