CA15215 - Innovative approaches in pork production with entire males (IPEMA)

Surgical castration of boars without pain relief is now considered unacceptable. Stakeholders of the pork chain committed themselves to voluntarily end surgical castration of male pigs in Europe by January 1st, 2018. The production of entire males (EM) or immunocastrates (IC) results in new challenges in management of product quality (detecting and reducing boar taint, coping with extreme leanness), specific nutritional requirements, appropriate animal management and housing to reduce boar taint and address associated animal welfare issues (aggression, sexual behaviour). Thus, EM and IC production require reconsideration of the whole pork production system, and innovations at all levels of the food chain to achieve high sustainability and product quality. Partially, these aspects have been studied previously but there are is still a range of unresolved relevant issues. Additionally, a knowledge gap exists between the Western and Eastern parts of Europe, either due to differences in traditional production systems or differences in public perception of animal welfare aspects. A better coordinated research effort and training of young researchers at international level would significantly improve research efficiency, accelerate knowledge acquisition and dissemination. The COST Action will accelerate innovations by networking, by developing and disseminating science-based best practices to achieve good production quality with EM or IC. It will support the meat industry to cope with the challenge to produce equally valuable products from meat of EM or IC which is adequate for regional specific consumer demands. Action keywords Sustainable animal friendly pork production with males - High quality pork production with boars and immunocastrates - Consumer sensibilization and information - Genetics of boar taint prevention - Product development and carcass neo-gradin

Alternatives to Piglet Castration: From Issues to Solutions

Because castrated male pigs convert feed into meat less efficiently than entire males, they are less efficient regarding the utilization of resources. Moreover, surgical castration without pain relief is painful to the piglet. This is why there is a growing consensus, at least in Western Europe, that it should be abandoned. There are currently three possible alternatives: surgical castration with pain relief, immunocastration, also known as vaccination against boar taint, and raising entire males. Using anesthesia and/or analgesia during surgical castration prevents pain to the piglet. Still, this can be considered only as an intermediate solution for the short-term because it is still adverse to animal integrity, it is still resource-inefficient and it adds costs. For these reasons, surgical castration with pain relief is not sustainable for the long run in mainstream production, even if it might possibly be a solution for some production systems aiming at very high-quality products. The review papers presented in this special issue focus on the two remaining alternatives: entire males and immunocastration.info:eu-repo/semantics/publishedVersio

Photoperiodic Effects on Diurnal Rhythms in Cell Numbers of Peripheral Leukocytes in Domestic Pigs

The photoperiod is known to modulate immune cell number and function and is regarded essential for seasonal disease susceptibility. In addition, diurnal variations in the immune system are regarded important for immune competence. Whereas few studies investigated the influence of season, none investigated the specific effect of the photoperiod on these diurnal immune rhythms until now. Therefore, the present study compared diurnal rhythms in cell numbers of peripheral leukocyte types in domestic pigs held either under long day conditions (LD) or short day conditions (SD). Cosinor analyses of cell numbers of various peripheral leukocyte subtypes investigated over periods of 50 h revealed distinct photoperiodic differences in diurnal immune rhythms. Relative amplitudes of cell numbers of total leukocytes, NK cells, T cells, and monocytes in blood were higher under SD than LD. In addition, cell counts of total leukocytes, NK cells, T cells including various T cell subtypes, and eosinophils peaked earlier relative to the time of lights-on under SD than LD. In contrast, diurnal rhythms of neutrophil counts did not show photoperiodic differences. Mesor values did not differ in any leukocyte type. Generalized linear mixed model analyses revealed associations of leukocyte counts with plasma cortisol concentration and activity behavior in most investigated cell types. Moreover, the present study demonstrated photoperiodic effects on diurnal rhythms in plasma cortisol concentrations and activity behavior, which is in agreement with human and primate studies. The results of the present study imply stronger rhythmicity in leukocyte counts in general under SD. Common intrinsic mechanisms seem to regulate photoperiodic effects on diurnal rhythms in leukocyte counts, except for neutrophils, in domestic pigs. Our results reveal considerable insights into the regulation of immune rhythms in diurnally active species

Attitudes and beliefs of Eastern European consumers towards piglet castration and meat from castrated pigs

Castration of male piglets is a common practice to avoid boar taint but is being questioned. The present work has an exploratory character and aims to investigate the beliefs and attitudes of Eastern European consumers regarding boar taint, surgical castration immunocastration and perception of meat from castrated pigs and to find out possible segments of consumers regarding these attitudes and beliefs. For this purpose, a consumer study was carried out involving 5508 consumers from 13 Eastern European countries (Bosnia and Herzegovina, Bulgaria, Czech Republic, Croatia, North Macedonia, Hungary, Moldova, Poland, Romania, Serbia, Slovakia, Slovenia and Ukraine). The questionnaire included statements related to beliefs about castration and perception of meat from castrated pigs, attitudes towards meat from castrated pigs. Results show that in general beliefs and attitudes of the consumers are not defined, probably because of the lack of knowledge (information was not provided to the consumers) towards these issues. Three different clusters of consumers were obtained with different beliefs towards castration.info:eu-repo/semantics/publishedVersio

Connexin30.2:<i>In vitro</i> interaction with connexin36 in hela cells and expression in AII amacrine cells and intrinsically photosensitive ganglion cells in the mouse retina

Electrical coupling via gap junctions is an abundant phenomenon in the mammalian retina and occurs in all major cell types. Gap junction channels are assembled from different connexin subunits, and the connexin composition of the channel confers specific properties to the electrical synapse. In the mouse retina, gap junctions were demonstrated between intrinsically photosensitive ganglion cells and displaced amacrine cells but the underlying connexin remained undetermined. In the primary rod pathway, gap junctions play a crucial role, coupling AII amacrine cells among each other and to ON cone bipolar cells. Although it has long been known that connexin36 and connexin45 are necessary for the proper functioning of this most sensitive rod pathway, differences between homocellular AII/AII gap junctions and AII/ON bipolar cell gap junctions suggested the presence of an additional connexin in AII amacrine cells. Here, we used a connexin30.2-lacZ mouse line to study the expression of connexin30.2 in the retina. We show that connexin30.2 is expressed in intrinsically photosensitive ganglion cells and AII amacrine cells. Moreover, we tested whether connexin30.2 and connexin36 – both expressed in AII amacrine cells – are able to interact with each other and are deposited in the same gap junctional plaques. Using newly generated anti-connexin30.2 antibodies, we show in HeLa cells that both connexins are indeed able to interact and may form heteromeric channels: both connexins were co-immunoprecipitated from transiently transfected HeLa cells and connexin30.2 gap junction plaques became significantly larger when co-expressed with connexin36. These data suggest that connexin36 is able to form heteromeric gap junctions with another connexin. We hypothesize that co-expression of connexin30.2 and connexin36 may endow AII amacrine cells with the means to differentially regulate its electrical coupling to different synaptic partners

Large-scale mapping of mutations affecting zebrafish development

BACKGROUND: Large-scale mutagenesis screens in the zebrafish employing the mutagen ENU have isolated several hundred mutant loci that represent putative developmental control genes. In order to realize the potential of such screens, systematic genetic mapping of the mutations is necessary. Here we report on a large-scale effort to map the mutations generated in mutagenesis screening at the Max Planck Institute for Developmental Biology by genome scanning with microsatellite markers. RESULTS: We have selected a set of microsatellite markers and developed methods and scoring criteria suitable for efficient, high-throughput genome scanning. We have used these methods to successfully obtain a rough map position for 319 mutant loci from the Tübingen I mutagenesis screen and subsequent screening of the mutant collection. For 277 of these the corresponding gene is not yet identified. Mapping was successful for 80 % of the tested loci. By comparing 21 mutation and gene positions of cloned mutations we have validated the correctness of our linkage group assignments and estimated the standard error of our map positions to be approximately 6 cM. CONCLUSION: By obtaining rough map positions for over 300 zebrafish loci with developmental phenotypes, we have generated a dataset that will be useful not only for cloning of the affected genes, but also to suggest allelism of mutations with similar phenotypes that will be identified in future screens. Furthermore this work validates the usefulness of our methodology for rapid, systematic and inexpensive microsatellite mapping of zebrafish mutations

Synaptic Transmission from Horizontal Cells to Cones Is Impaired by Loss of Connexin Hemichannels

In the vertebrate retina, horizontal cells generate the inhibitory surround of bipolar cells, an essential step in contrast enhancement. For the last decades, the mechanism involved in this inhibitory synaptic pathway has been a major controversy in retinal research. One hypothesis suggests that connexin hemichannels mediate this negative feedback signal; another suggests that feedback is mediated by protons. Mutant zebrafish were generated that lack connexin 55.5 hemichannels in horizontal cells. Whole cell voltage clamp recordings were made from isolated horizontal cells and cones in flat mount retinas. Light-induced feedback from horizontal cells to cones was reduced in mutants. A reduction of feedback was also found when horizontal cells were pharmacologically hyperpolarized but was absent when they were pharmacologically depolarized. Hemichannel currents in isolated horizontal cells showed a similar behavior. The hyperpolarization-induced hemichannel current was strongly reduced in the mutants while the depolarization-induced hemichannel current was not. Intracellular recordings were made from horizontal cells. Consistent with impaired feedback in the mutant, spectral opponent responses in horizontal cells were diminished in these animals. A behavioral assay revealed a lower contrast-sensitivity, illustrating the role of the horizontal cell to cone feedback pathway in contrast enhancement. Model simulations showed that the observed modifications of feedback can be accounted for by an ephaptic mechanism. A model for feedback, in which the number of connexin hemichannels is reduced to about 40%, fully predicts the specific asymmetric modification of feedback. To our knowledge, this is the first successful genetic interference in the feedback pathway from horizontal cells to cones. It provides direct evidence for an unconventional role of connexin hemichannels in the inhibitory synapse between horizontal cells and cones. This is an important step in resolving a long-standing debate about the unusual form of (ephaptic) synaptic transmission between horizontal cells and cones in the vertebrate retina

Growth and growth regulation of the pig

Aufbauend auf Literaturbefunden wird ein Überblick über die Grundlagen des Wachstums beim Schwein gegeben und Besonderheiten in der Entwicklung einzelner Gewebe dargestellt. Schwerpunkt stellt die endokrine Steuerung des Wachstums und die Beeinflussung der hormonalen Regulation durch endogene und exogene Faktoren dar. In eigenen experimentellen Arbeiten wurde der Einfluss endogener und exogener Faktoren auf die Sekretion von Wachstumshormon (Growth hormone, GH), IGF-I (Insulin-like growth factor-I) und Insulin sowie Cortisol und Gonadensteroiden beim Schwein untersucht. Zusätzlich wurde auch in einigen Versuchen Osteocalcin gemessen. Die Messung dieser Substanz im Blutplasma erlaubt es, die Syntheseaktivität der Osteoblasten kontinuierlich darzustellen und endokrine Einflüsse auf die Syntheseleistung zu beschreiben. Folgende experimentelle Befunde konnten damit erarbeitet werden: Bei wachsenden Ebern, Jungsauen und Börgen wurden altersabhängige Veränderungen der GH- und IGF-I Sekretion beschrieben und in Beziehung zum Wachstumsverlauf gesetzt. Der Verlauf der IGF-I Werte spiegelt die altersabhängigen Veränderungen des Wachstumsvermögens wider und korreliert mit den täglichen Zunahmen und dem Proteinansatz. Die Osteocalcin-Konzentrationen waren stets mit den IGF-I Werten korreliert, die altersabhängige Reduktion der Osteocalcinwerte war jedoch stärker ausgeprägt. Die Unterschiede stehen in Übereinstimmung mit der Betonung des Knochenwachstums in der frühen Jugendentwicklung. Unabhängig vom Alter und Geschlecht zeigt IGF-I eine deutliche Rhythmik in der Sekretion mit einer Schwingungsdauer von zwei bis drei Wochen. Diese Rhythmik spiegelte sich z.T. auch in der Sekretion von Cortisol und Osteocalcin wider und wird als Hinweis auf Wachstumsschübe interpretiert, wie sie für das Knochenwachstum bei anderen Spezies beschrieben wurden. Die Steuerung der GH-Sekretion erfolgt in Wechselwirkung mit den Hormonen, die die Reproduktion steuern. Bereits auf Ebene der Hypophyse lassen sich Wechselwirkungen zwischen dem Hormon, das die Freisetzung der Gonadotropine steuert (Gn-RH), und GH-RH, das die Freisetzung von Wachstumshormon (GH) bedingt, nachweisen. Die biologische Bedeutung der Wechselwirkungen wird darin gesehen, dass hierdurch sichergestellt wird, dass jeweils nur eine Leistung dominiert. Gonadensteroide haben eine direkte Wirkung auf die Freisetzung von GH und die IGF-I Bildung. Während Testosteron beim Schwein die GH- und IGF-I-Bildung nur geringfügig beeinflusst, stimulierten niedrige Estrogenkonzentrationen sowohl die GH- als auch die IGF-I Sekretion. Weiter steigende Estrogenkonzentrationen stimulierten zwar noch die IGF-I Bildung, die GH-Sekretion war jedoch gehemmt. Progesteron verminderte tendenziell sowohl die GH- als auch die IGF-I Sekretion. Die dargestellten Konsequenzen der Gonadensteroide für die GH-/IGF-I Sekretion konnte auch unter physiologischen Bedingungen an zyklischen Sauen nachvollzogen werden. Zusätzlich wurden Genotypen mit unterschiedlicher Schwerpunktsetzung verglichen. Bei wachsenden männlichen Tieren der Rassen Large White (mittlere Fruchtbarkeit, hohes Wachstumsvermögen) und Meishan (hohe Fruchtbarkeit, geringes Wachstumsvermögen) sowie europäischen Wildschweinen (Stammform, geringes Wachstumsvermögen, geringe Fruchtbarkeit) wurden jeweils der Wachstumsverlauf im ersten Lebensjahr und endokrine Parameter analysiert. Die Studien zeigen, dass sich das hohe Wachstumsvermögen der europäischen Hausschweinrasse Large White sowohl durch ein hohes Niveau des anabolen Hormons IGF-I als auch durch eine verminderte Glucocorticoid-Freisetzung bedingt ist. Das niedrige Muskelbildungsvermögen bei der chinesischen Rasse erklärt sich sowohl durch niedrige Sekretion von IGF-I bei verstärkter Insulinsensitivität als auch eine hohe Cortisolsekretion. Die gleichzeitig erhöhten Androgenwerte erklären jedoch auch, warum die chinesischen Rasse den europäischen Wildschweinen (mit hohen IGF-I Werten, hohen Cortisolwerten aber nur saisonal erhöhten Androgenwerten) dennoch leicht im Wachstumspotential überlegen ist. Die endokrinen Unterschiede lassen sich dahingehend interpretieren, dass die züchterische Steigerung des Wachstumsvermögens nicht nur auf einer Erhöhung der anabolen Vorgänge, sondern auch auf einer Verminderung der katabolen Prozesse beruht. Als wesentlicher exogener Faktor wurde der Einfluss der Photoperiode auf die endokrine Regulation von Futteraufnahme und Wachstum untersucht. Dabei konnte die Abhängigkeit der IGF-I-Sekretion von der Jahreszeit sowohl bei Keilern, als auch bei Hausschweinebern nachgewiesen werden, während die Verlaufskurven bei Meishan-Ebern unabhängig von der Jahreszeit waren. Dass bei europäischen Haus- und Wildschweinen dabei überwiegend Einflüsse der Photoperiode wirken, zeigen die experimentellen Arbeiten mit Lichtprogrammen. Beim Keiler konnten so lichtabhängig drei unterschiedliche Stoffwechselphasen im Jahresverlauf beschrieben werden, die prinzipiell auch beim Hausschwein noch vorhanden sind, auch wenn das Ausmaß geringer ist, als beim Wildschwein. Neben der Photoperiode kommt der Energieversorgung und der Futterzusammensetzung erhebliche Bedeutung für die IGF-I und GH-Sekretion zu. So konnte in mehreren experimentellen Ansätzen nachgewiesen werden, dass die IGF-I Bildung sensibel auf die Energieversorgung reagiert. Die Protein- und Tryptophanversorgung haben hingegen einen weitaus schwächeren Einfluss auf die IGF-I Bildung als die Energieversorgung.The endocrine regulation of growth was studied in wild and domestic pigs by systematic measurements of growth hormone (GH), IGF-I (Insulin-like growth factor-I), insulin and steroid hormones. In some of the studies measurements of osteocalcin were included to monitor the anabolic activity of osteoblasts under different physiological situations. The following results were obtained. Age dependent changes in the secretion of GH- und IGF-I were studied in growing boars, barrows and gilts and compared to growth parameters. IGF-I reflected age dependent changes in the growth potential and were closely correlated with daily gain and protein accretion. Osteocalcin concentrations were always correlated to IGF-I, the age dependent decrease, however, was more pronounced for osteocalcin than for IGF-I, reflecting the allometric predominance of skeletal growth in very young pigs. Osteocalcin concentrations were always correlated to IGF-I, the age dependent decrease was more pronounced for osteocalcin than for IGF-I, reflecting the allometric predominance of bone growth in very young pigs. Additionally a clear rhythm of IGF-I secretion was obvious with a period length of two to three weeks. This rhythm was similarly found for cortisol secretion and peripheral osteocalcin and might be related to allometric growth phenomena, as described for skeletal growth in other species. Regulation of GH-secretion includes interactions with hormones involved in the regulation of reproduction. At the pituitary level such interactions were demonstrated for Gn-RH and GH-RH. Gonadal steroids directly influence the release of GH and IGF-I secretion. The analysis of physiological situations as well as application studies revealed that testosterone had only a minor effect on both hormones. In contrast, low concentrations of estradiol clearly stimulated GH- and IGF-I secretion as well. Further increasing estradiol concentrations were still stimulatory for IGF-I but inhibited GH-secretion. Progesterone tended to lower both, GH and IGF-I secretion. Additionally Large White, Meishan and European wild boar were studied for differences in growth performance and the endocrine regulation during the first year of life. The studies revealed, that the high growth potential of LW is related both, to high levels of anabolic IGF-I and concomitantly low levels of catabolic cortisol. In Meishan and wild boars cortisol levels were high, but in Meishan boars additionally high concentrations of gonadal steroids were measured, which may explain the higher growth rate in MS when compared to wild boars. IGF-I concentrations were even higher in wild boars than in LW. Thus it is assumed that selection for growth potential led to a concomitant change in the level of catabolic glucocorticoids. The influence of the season and photoperiod on endocrine parameter, food intake and growth was investigated in wild and domestic boars. A seasonal influence on IFG-I secretion was obvious in wild and LW boars, but not in Meishan boars. It was further proven by the application of a reverse light programme that the pattern is mainly due to the influence of the photoperiod. In the wild boar three distinct metabolic periods were obvious, which were also found in domestic pigs, but less pronounced. In addition to the photoperiod food intake and food composition modulate GH and IGF-I secretion in the pig. Several experiments revealed, that IGF-I secretion is predominantly influenced by the energy supply and only to a lower extend by protein and tryptophane content of the ration