Behavioural and Physiological Aspects of Cardiac Development in the Dog

Abstract— Aspects of development of the canine heart were investigated. During postnatal growth, a linear relationship between heart weight and total body weight was found. There was a decrease in heart rate after 2 weeks of age which was not correlated with alterations in size of the heart but with increasing vagal tone for atropine caused the greatest increase in heart rate from the resting level at 2 weeks of age. Rearing pups under conditions of stress (supra-normal stimulation or “handling”) abolished the vagal-slowing which occurred in normal pups at 2 weeks of age. A marked increase in heart rate (increased sympathetic tone) was observed in these handled subjects and it was surmised that early experience (e.g. stress factors in early life) can significantly modify the ontogeny of the heart. The clinical significance of these observations is discussed. Résumé— Les aspects du developpement du coeur du chien ont été investigués. Durant la croissance postnatale, une relation linéaire entre le poids du coeur et le poids total du corps a été trouvée. Il y a eu un décroissement dans le taux du coeur après 2 semaines, décroissement qui n'est pas en corrélation avec les alterations dans la taille du coeur mais avec un accent pneumogastrique augmentant car l'atropine a causé la plus grande augmentation des battements du coeur du repos à 2 semaines. Elever des chiots sous des conditions de contrainte (stimulation supra-normale ou “maniement’) abolit le ralentissement pneumogastrique qui survient chez des chiens normaux à 2 semaines. Une augmentation marquée des battements du coeur (accent sympathique augmenté) a été observed chez ces sujets manipulés et il a été conjectureé qu'une expérience précoce (c.a.d. des facteurs de contrainte dans le jeune ǎge) peut modifier d'une maniere significative Pontogenèse du coeur. La signification clinique de ces observations a été discutée. Zusammenfassung— Einige Faktoren über die Entwicklung des Hundeherzes wurden untersucht. In den Tagen nach der Geburt, eine linealische Beziehung zwischen dem Herzgewicht und Körpergewicht wurde festgesetzt. Abnahme der Herzfrequenz tratt nach 2 Wochen an, und hatte keine Beziehung mit den Anderungen der Herzgrösse. Diese Abnahme ist mit zunehmenden Vagustonus verbunden, Atropine verursachte die grösste Herzfrequenz im Alter von 2 Wochen. Vagustonus konnte man nicht in jungen Hunden finden welche unter Aufstrengung aufgezogen waren (supra-normale Reizung oder “handling’). In diesen Hunden eine auffallende Verstarkung der Herzfrequenz wurde gefunden, (erhöht sympathischer tonus) und man kann vermuten dass früheErfahrung die Ontogenese des Herzes bedeutend modifiziert.     

Leukaemia in a cat with concurrent Cladosporium infection

A case of lymphocytic leukaemia with metastatic brain lesions and a concurrent Cladosporium trichoides infection is described in a cat. The lesions in the brain consisted of haemorrhage, foci of neoplastic cells in the parenchyma and perivascular cuffing with neoplastic cells. Lesions due to Cladosporium were found only in the kidney and were circumscribed necrotic areas surrounded by neutrophils and macrophages with hyphae in the centre. Identification of the fungus was made by growth characteristics, morphology, biochemical tests and experimental animal inoculation. Résumé. On décrit, chez un chat, un cas de leucétmie lymphocytique avec des lésions cérébrales métastatiques et une infection concourante Cladosporium trichoides. Les lésions cérébrales consistaient en une hémorragie, des foyers de cullules néoplastiques dans le parenchyme et un cuffing périvasculaire avec cellules néoplastiques. On a trouvé des lésions dues au Cladosporium dans le rein seulement et elles étaient des régions nécrotiques circonscrites entourées de neutrophils et de macrophages avec des hyphes au centre. On a identifié le fongus grâce aux caractéristiques de croissance, à la morphologie, à des tests biochimiques et à une infection chez des animaux expérimentaux. Zusammenfassung. Lymphozythämische Leukämiemit metastatischer Gehirnverletzung und begleitender Cladosporium trichoides Infiszierung, ist im Fall einer Katze beschrieben. Die Gehirnverletzung bestand aus Blutung, Foci der neoplastischen Parenchyma Zellen und perivaskularer Cuffing der neoplastichen Zellen. Cladosporium entstammende Verletzungsspuren wurden nur in der Niere entdeckt, und zwar, als abgestorbene Zonen, die von Hyphen-kernigen Neutrophil und Makrophage umrahmt waren. Die Fungus Identifikation wurde an Merkmale des Wachstums, Morphologie, biochemischen Proben und Infektion der Versuchstiere, vorgenommen.     

An assessment of cereal grains and other starch sources in diets for barramundi (Lates calcarifer) – implications for nutritional and functional qualities of extruded feeds

This study examined the digestibilities of whole diets and ingredients of a range of starch/cereal grains when fed to barramundi (Lates calcarifer). The ingredients included wheat, oats, sorghum, triticale, barley, among others. Twelve diets were prepared using a twin‐screw extruder to mimic modern aquafeed‐manufacturing processes. The diets were then fed to juvenile barramundi and the faeces collected using stripping methods. Significant variability in the digestible energy and starch value was seen among the test ingredients and diets. Diet starch digestibility ranged from 49.1% to 93.9%. Ingredient starch digestibility ranged from 18.0% to 96.5%. Among the different starch ingredients, a strong negative correlation between the ingredient amylopectin content and starch digestibility of that ingredient was observed. This relationship was also mirrored by a similar relationship, although not as strong, between total starch and starch digestibility. This study demonstrates that barramundi have limited ability to digest starch and that there is an effect of inclusion level on the ability of the animal to digest this nutrient. But it also demonstrates that there is a wide range of cereal sources that can be effectively used as starch sources in extruded diets for this species.     

Intra‐population variability of life‐history traits and growth during range expansion of the invasive round goby,Neogobius melanostomus

Abstract Fish can undergo changes in their life‐history traits that correspond with local demographic conditions. Under range expansion, a population of non‐native fish might then be expected to exhibit a suite of life‐history traits that differ between the edge and the centre of the population’s geographic range. To test this hypothesis, life‐history traits of an expanding population of round goby, Neogobius melanostomus (Pallas), in early and newly established sites in the Trent River (Ontario, Canada) were compared in 2007 and 2008. Round goby in the area of first introduction exhibited a significant decrease in age at maturity, increased length at age 1 and they increased in GSI from 2007 to 2008. While individuals at the edges of the range exhibited traits that promote population growth under low intraspecific density, yearly variability in life‐history traits suggests that additional processes such as declining density and fluctuating food availability are influencing the reproductive strategy and growth of round goby during an invasion.     

Spawning of North Sea fishes linked to hydrographic features

Spawning of fishes takes place across a wide area of the North Sea. However, more intense spawning is seen in restricted areas, indicating that such areas present favorable conditions. To update information on fish spawning in the North Sea and analyze potential linkages to hydrographic characteristics, an internationally coordinated survey was conducted in the winter/spring of 2004. Oblique hauls for fish eggs and larvae and vertical profiles of temperature and salinity were carried out at 393 stations across the entire North Sea. The hydrography was strongly influenced by the interfacing of water masses of different salinity, and frontal zones were seen along all coastal areas and off the Dogger and Fisher Banks. Total abundances of eggs and larvae, including fish species such as cod, haddock, plaice, long rough dab and sandeel, peaked in the vicinity of the frontal areas. Hence our findings indicate that the main spawning locations of fish are linked to recurrent hydrographic features such as salinity fronts. Such a linkage may provide survival advantages, as the fronts present favorable feeding conditions, and the related physical processes may confine egg and larval dispersal and transport them towards suitable nursery habitats.     

Reducing fish losses to cormorants using artificial fish refuges: an experimental study

Abstract  The hypothesis that the introduction of artificial refuges might provide protection for fish and reduce the level of cormorant predation was tested in two, paired-pond, cross-over trials during the winters of 2003 and 2004, using a 'refuge' pond and an adjacent equivalently stocked 'control' pond. There were 77% fewer cormorant visits to the refuge pond than the control pond, on average. There was also a 67% fall in the mean mass of fish consumed per cormorant visit and 79% less fish mass lost in the refuge pond. The results are discussed in the context of interactions between cormorants and fish and the potential use of the tool in fisheries management.     

The Clinical Significance of Age Differences in the Effects of Decerebration and Spinal Cord Transection in the Dog

Abstract— The effects of decerebration and spinal cord transection were observed in twenty-two dogs aged from birth to 6 wk of age. In the youngest dogs, decerebrations caused no marked neurologic or behavioural changes and similarly spinal shock was not observed in the more immature subjects. These findings are discussed in the light of neurophysiological development of the dog and related (non-precocial) species. Diagnosis and prognosis of neurologic disorders in the neonate dog should be guarded since few higher cortical structures are integrated in behavioural organization until at a later age. The gradual emergence of clinical symptoms if studied early in life may constitute a regime of developmental neurologic diagnosis which would aid prognosis, location and extent of the lesion. Résumé— Les effets de la décérébration et de la section transversale de la moelle épinière ont été observés chez 22 chiens, leur âge variant du moment de la naissance jusqu'à six semaines. Chez les jeunes chiens, la décérébration n'a pas causé des changements neurologiques ou de comportement, marquées; un choc spinal n'a été observé non plus chez les sujets plus immatures. Ces résultats sont discutés dans la lumière du développement neurophysiologique du chien et des espèces apparentées (non précoces). Le diagnostique et le pronostique de désordres neurologiques chez le chien nouveauné devraient être pris en consideration, étant donné que peu de structures corticales plus importantes sont integrées dans l'organisation du comportement, avant un âge plus avancé. L'apparition progressive de symptomes cliniques, s'ils sont étudés tôt, dans le première de la vie, peut constituer une méthode de diagnostique neurologique qui peut aider la pronostique, la localisation et l'étendue de la lésion. Zusammenfassung— Der Effekt von Hirnentfernung und Rückenmarktransektion wurde bei 22 neugeborenen bis 5 Wochen alten Hunden beobachtet. Bei den jüngsten Hunden verursachte Hirnentfernung weder bemerkenswerte neurologische noch psychologische Veränderungen; auch Rückenmarkschock wurde bei weniger entwickelten Versuchstieren nicht beobachtet. Diese Feststellungen sind im Sinne neuro-physiologischer Entwicklung bei Hunden und verwandten (nicht frühreifen) Tierarten besprochen. Diagnosen und Prognosen über neurologische Störungen bei neonatalen Hunden sollten mit Vorchicht behandelt werden, da wenige höhere, äussere Strukturschichten vor einem gewissen Alter in den Aufbau des Behaviorsmus' einbezogen werden. Das im frühen Alter beobachtete allmähliche Auftauchen von klinischen Symptomen könnte zu einer Richtung in neurologischer Entwicklingsdiagnose führen, welche zu Prognosen, zu örtlichen Bestimmungen und nur Beurteiluzg des Ausmasses der Verletzung beitragen würde.