Evidence from Studies with Heat-Stressed Caco-2 Cells, C. elegans and Growing Broilers

Climatic changes and heat stress have become a great challenge in the livestock industry, negatively affecting, in particular, poultry feed intake and intestinal barrier malfunction. Recently, phytogenic feed additives were applied to reduce heat stress effects on animal farming. Here, we investigated the effects of ginseng extract using various in vitro and in vivo experiments. Quantitative real-time PCR, transepithelial electrical resistance measurements and survival assays under heat stress conditions were carried out in various model systems, including Caco-2 cells, Caenorhabditis elegans and jejunum samples of broilers. Under heat stress conditions, ginseng treatment lowered the expression of HSPA1A (Caco-2) and the heat shock protein genes hsp-1 and hsp-16.2 (both in C. elegans), while all three of the tested genes encoding tight junction proteins, CLDN3, OCLN and CLDN1 (Caco-2), were upregulated. In addition, we observed prolonged survival under heat stress in Caenorhabditis elegans, and a better performance of growing ginseng-fed broilers by the increased gene expression of selected heat shock and tight junction proteins. The presence of ginseng extract resulted in a reduced decrease in transepithelial resistance under heat shock conditions. Finally, LC-MS analysis was performed to quantitate the most prominent ginsenosides in the extract used for this study, being Re, Rg1, Rc, Rb2 and Rd. In conclusion, ginseng extract was found to be a suitable feed additive in animal nutrition to reduce the negative physiological effects caused by heat stress. View Full-Tex

Acoustic mate choice, proximate mechanism of decision making and selective phonotaxis under laboratory and real world conditions in the field cricket Gryllus bimaculatus

Individuen m\ufcssen in unterschiedlichsten Situationen Entscheidungen treffen, um ihre evolution\ue4re Fitness zu maximieren. Dabei ist die Wahl eines geeigneten Paarungspartners eine der folgeschwersten Entscheidungen. Weibliche Feldgrillen evaluieren die Qualit\ue4t potentieller Paarungspartner anhand m\ue4nnlicher Ges\ue4nge, die sich in mehreren Parametern wie Frequenz, Gesangsrate und Amplitude unterscheiden. Der Gro fteil bisheriger Studien zum weiblichen Pr\ue4ferenzverhalten untersuchte die Phonotaxisleistung unter kontrollierten Laborbedingungen ohne auf den Einfluss der Komplexit\ue4t eines Habitats auf die Verhaltensantwort einzugehen.Der Schwerpunkt der vorliegenden Arbeit liegt in der Etablierung einer realistischen Wahlsituation in einer wirklichkeitsnahen physikalischen Umwelt, um Vorhersagen \ufcber das Entscheidungsverm\uf6gen von Weibchen der Grillenart Gryllus bimaculatus in deren nat\ufcrlichem Habitat treffen zu k\uf6nnen. Zwar zeigen sich im Freiland dieselben Pr\ue4ferenzen wie unter Laborbedingungen f\ufcr eine hohe Rrate, eine hohe Signalamplitude und eine bestimmte Tr\ue4gerfrequenz, doch m\ufcssen die Unterschiede der gebotenen Signalparameter deutlich gr\uf6 fer sein um auch im nat\ufcrlichen Habitat erkannt zu werden.Physikalische Hindernisse der biologischen Umwelt beeinflussen den akustischen cbertragungskanal und st\uf6ren den Intensit\ue4tsgradient der Grillenges\ue4nge bzw. degradieren deren Richtungsinformation. Subtile Unterschiede zwischen mehreren Gesangsvarianten, die unter Laborbedingungen signifikante Entscheidungen hervorrufen, k\uf6nnen somit im nat\ufcrlichen Habitat nur eine untergeordnete Rolle bei der Partnerwahl spielen.Obwohl eine komplexe Umwelt eine erh\uf6hte Unterscheidungsschwelle bewirkt, so zeigen kombinierte Verhaltens- und neurophysiologische Untersuchungen, dass die Detektionsleistung von G. bimaculatus im Freiland selbst nach einer Manipulation des Druckgradientenempf\ue4ngers kaum beeinflusst, wodurch sie sich stark von der nahe verwandten Art G. campestris unterscheidet.Individuals have to make decisions in choice situations of variable context to maximize their evolutionary fitness. One of the most crucial decisions in an animal?s life is to choose a proper mate. Female field crickets evaluate the quality of potential mating partners on male calling songs differing in various song traits as the carrier frequency, chirprate or their amplitude. Most studies on sexual selection investigated the phonotactic performance under controlled laboratory conditions without dealing with the influence of habitat complexity on female choice behaviour.The aim of the present study was the establishment of realistic choice situation under real world conditions, to make predictions on the decision making process of females of the cricket species Gryllus bimaculatus in their natural habitat. Indeed, in outdoor experiments we observed the same female preferences for a high chirprate, high amplitude and a certain carrier frequency, but the differences necessary for a significant preference between two song models were considerably larger in the natural habitat compared to laboratory conditions.Due to obstacles in the transmission channel of the signal the directional information is strongly degraded and also the intensity gradient of calling songs is impaired in the natural habitat. As a consequence, subtle differences between alternative song models, which may be relevant for a significant choice under lab conditions, will no more be detectable and play only minor role for mate choice under natural conditions.Although females showed increased detection thresholds for song trait differences in more complex environments, a neuroethological approach revealed, that female G. bimaculatus easily localize sound sources in their natural habitat even with a manipulated pressure difference receiver, which is not true for the closely related cricket species G. campestris.Stefan HirtenlehnerZsfassung in dt. und in engl. SpracheGraz, Univ., Diss., 2014 2.163

Maskierung der Phonotaxis bei der Mittelmeerfeldgrille, Gryllus bimaculatus : Verhalten und Neurophysiologie

Die F\ue4higkeit eines Tieres Raubfeinde zu detektieren oder Sexualpartner zu lokalisieren ist in vielen F\ue4llen mit der Perzeption von akustischen Signalen gekoppelt. Hintergrundrauschen reduziert diese Detektions- und Diskriminationsleistung auf Empf\ue4ngerseite und minimiert so die evolution\ue4re Fitness der Invididuen. Dies trifft auch auf die Situation von Feldgrillen zu.In Habitaten hoher Diversit\ue4t, wie dem tropischen Regenwald von Panama, ergibt sich durch die Konkurrenz von bis zu 50 nachtaktiven, sympatrischen Grillenarten ein Schallpegel von max. 70 dB SPL, der die Verbreitungsdistanz von akustischen Signalen minimiert.Die vorliegende neuroethologische Studie untersucht die Maskierung einer Verhaltensantwort von Grillenweibchen (Phonotaxis) durch Hintergrundrauschen sowie m\uf6gliche neuronale Korrelate bei der Feldgrille Gryllus bimaculatus. Dazu wurden 1) Grillench\uf6re unterschiedlicher spektraler Zusammensetzung zwischen 3kHz und 6,8kHz und 2) ein einzelner heterospezifischer Grillengesang, dessen Frequenz mit jener des arteigenen Signals \ufcbereinstimmte, der aber im Duty-Cycle variiert wurde, als Maskierung eingesetzt. Die Ergebnisse zeigen einen gr\uf6 feren maskierenden Einfluss auf das phonotaktische Verhalten hervorgerufen durch den einzelnen artfremden Grillengesang als durch die Grillench\uf6re. Je h\uf6her der Duty-Cycle lag, desto gr\uf6 fer waren der Fehler im mittleren Laufwinkel und die gelaufene Distanz.Weiters untersuchte ich in denselben Individuen die Aktivierung des AN1-Neurons, dessen Relevanz f\ufcr das phonotaktische Verhalten hinl\ue4nglich bekannt ist. Die akustische Stimulation glich jener aus den Verhaltensexperimenten. Die Ergebnisse zeigen eine Abschw\ue4chung der neuronalen Antwort auf das Rauschen, sofern der Schallpegel des arteigenen Signals den des Rauschens \ufcbertraf. Dieser als 'Selective Attention' beschriebene neuronale Mechanismus bedingt ebenso eine Reduktion der Antwort auf arteigene Signale geringer Intensit\ue4t in lauten Umweltbedingungen.The ability of animals to detect predators or to localize mates is often linked to the perception of acoustic signals. Background noise reduces the performance of detection and discrimination of receivers and lowers their evolutionary fitness. So is the situation in field crickets. Masking noise conditions are even more pronounced in habitats with high diversity of species. For example, in the tropical nocturnal rainforest of Panama a background noise level of 70 dB SPL has been recorded due to singing activity of about 50 cricket species.In my Master thesis I analyzed the phonotactic behaviour of female Gryllus bimaculatus under masking noise conditions, and subsequently the possible neuronal substrates for this behaviour. I used two noise stimuli, which were presented non-directionally in a no-choice paradigm together with the conspecific calling-song: 1) a mix of nine heterospecific cricket songs with carrier frequencies ranging between 3 kHz to 6.8 kHz and 2) a single heterospecific song at a carrier frequency of 4.9 kHz. The latter noise was varied in his duty-cycle (i.e. the on-time) from 10% to 90%. Behavioural results demonstrate stronger masking of phonotaxis due to the single heterospecific song compared to the whole chorus of crickets. The higher the duty-cycle of noise the larger was the error in the walking angle and the larger was the walking distance.I also studied the activation of ascending neurone 1, whose relevance for phonotactic behaviour is well-established. The acoustic stimulation was equal to the stimulation used in the behavioural experiments. The results demonstrate an attenuation of neuronal response to noise, if the sound level of the calling-song was higher than the intensity of noise (selective attention). The same mechanism also had the effect, that the representation of the calling-song in the nervous response was strongly reduced when the sound pressure level of masking noise was higher than the one of the conspecific signal.Stefan HirtenlehnerGraz, Univ., Dipl.-Arb., 201

Extracts Prepared from Feed Supplements Containing Wood Lignans Improve Intestinal Health by Strengthening Barrier Integrity and Reducing Inflammation

Lignans are known to exhibit a broad spectrum of biological activities, indicating their potential as constituents of feed supplements. This study investigated two extracts derived from the feed supplements ‘ROI’ and ‘Protect’—which contain the wood lignans magnolol and honokiol (‘ROI’), or soluble tannins additional to the aforementioned lignans (‘Protect’)—and their impact on selected parameters of intestinal functionality. The antioxidant and anti-inflammatory properties of the extracts were determined by measuring their effects on reactive oxygen species (ROS) and pro-inflammatory cytokine production in vitro. The impact on intestinal barrier integrity was evaluated in Caco-2 cells and Drosophila melanogaster by examining leaky gut formation. Furthermore, a feeding trial using infected piglets was conducted to study the impact on the levels of superoxide dismutase, glutathione and lipid peroxidation. The Protect extract lowered ROS production in Caco-2 cells and reversed the stress-induced weakening of barrier integrity. The ROI extract inhibited the expression or secretion of interleukin-8 (IL-8), interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor α (TNFα). Moreover, the ROI extract decreased leaky gut formation and mortality rates in Drosophila melanogaster. Dietary supplementation with Protect improved the antioxidant status and barrier integrity of the intestines of infected piglets. In conclusion, wood lignan-enriched feed supplements are valuable tools that support intestinal health by exerting antioxidant, anti-inflammatory and barrier-strengthening effects

Ginseng Extract Ameliorates the Negative Physiological Effects of Heat Stress by Supporting Heat Shock Response and Improving Intestinal Barrier Integrity: Evidence from Studies with Heat-Stressed Caco-2 Cells, C. elegans and Growing Broilers

Climatic changes and heat stress have become a great challenge in the livestock industry, negatively affecting, in particular, poultry feed intake and intestinal barrier malfunction. Recently, phytogenic feed additives were applied to reduce heat stress effects on animal farming. Here, we investigated the effects of ginseng extract using various in vitro and in vivo experiments. Quantitative real-time PCR, transepithelial electrical resistance measurements and survival assays under heat stress conditions were carried out in various model systems, including Caco-2 cells, Caenorhabditis elegans and jejunum samples of broilers. Under heat stress conditions, ginseng treatment lowered the expression of HSPA1A (Caco-2) and the heat shock protein genes hsp-1 and hsp-16.2 (both in C. elegans), while all three of the tested genes encoding tight junction proteins, CLDN3, OCLN and CLDN1 (Caco-2), were upregulated. In addition, we observed prolonged survival under heat stress in Caenorhabditis elegans, and a better performance of growing ginseng-fed broilers by the increased gene expression of selected heat shock and tight junction proteins. The presence of ginseng extract resulted in a reduced decrease in transepithelial resistance under heat shock conditions. Finally, LC-MS analysis was performed to quantitate the most prominent ginsenosides in the extract used for this study, being Re, Rg1, Rc, Rb2 and Rd. In conclusion, ginseng extract was found to be a suitable feed additive in animal nutrition to reduce the negative physiological effects caused by heat stress