Effects of Varying Levels of Phytase Supplementation on Nutrient Digestibility in Horses Fed a Common Textured Ration

Department of Animal Scienc

Upland Nesting of American Bitterns, Marsh Hawks, and Short-Eared Owls

Nests of American Bitterns (Botaurus lentiginosus), marsh hawks (Circus cyaneus), and short-eared owls (Asio flammeus) are usually found in wetland habitats. Although large marshes containing dense stands of bulrushes (Scirpus), cattails (Typha), or other wetland vegetation are favored nesting cover, these birds have also been reported to nest in stands of tall, dense shrubs and grasses on the upland (Bent 1961, 1963; Palmer 1962; Sealy 1967; Stewart 1975). During 1968-74, we regularly found upland nests of these three species while conducting duck nesting studies in planted fields of undisturbed grass-legume cover in the Dakotas (Duebbert and Lokemoen 1976). Our findings on nest densities, hatching success, site characteristics, clutch sizes, and other ecological factors are presented in this paper. A bib (1975) indicated that the three species discussed in the present paper, in all or a significant part of their range, currently exhibit potentially dangerous, apparently non-cyclical population declines. Our general observations in North Dakota over the past 20 years also suggest an alarming decrease in populations of these birds during the breeding season. We believe that these population declines may be correlated with the widespread destruction or degradation of essential nesting habitats as agriculture has become increasingly more intensive

Conservation Tillage and Wildlife

The objective of the study conducted during 1984 and 1985 and reviewed here was to evaluate the amount of nesting and reproductive success of ducks in no-till winter wheat

Island Nesting of the Gadwall in North Dakota

Volume: 78Start Page: 12End Page: 2

From injury to full repair: nerve regeneration and functional recovery in the common octopus, Octopus vulgaris

Spontaneous nerve regeneration in cephalopod molluscs occurs in a relative short time after injury, achieving functional recovery of lost capacity. In particular, transection of the pallial nerve in the common octopus (Octopus vulgaris) determines the loss and subsequent restoration of two functions fundamental for survival, i.e. breathing and skin patterning, the latter involved in communication between animals and concealment. The phenomena occurring after lesion have been investigated in a series of previous studies, but a complete analysis of the changes taking place at the level of the axons and the effects on the animals' appearance during the whole regenerative process is still missing. Our goal was to determine the course of events following injury, from impairment to full recovery. Through imaging of the traced damaged nerves, we were able to characterize the pathways followed by fibres during regeneration and end-target re-innervation, while electrophysiology and behavioural observations highlighted the regaining of functional connections between the central brain and periphery, using the contralateral nerve in the same animal as an internal control. The final architecture of a fully regenerated pallial nerve does not exactly mirror the original structure; however, functionality returns to match the phenotype of an intact octopus with no observable impact on the behaviour of the animal. Our findings provide new important scenarios for the study of regeneration in cephalopods and highlight the octopus pallial nerve as a valuable 'model' among invertebrates

An epigenetic basis for essential hypertension

Essential hypertension – high blood pressure – is responsible for more disease and deaths worldwide than any other single health risk factor. Despite its thoroughly researched and confirmed heritability, essential hypertension lacks a genetic explanation. An underexplored cause for essential hypertension could be related to epigenetics. Epigenetic states dictate gene expression independent of variation in the underlying DNA sequence, and as such an aberrant epigenetic state would be invisible to conventional genetic association studies. In this work I proposed to investigate the hypothesis that epigenetic changes could contribute to the development of hypertension. In order to investigate this, I utilised the canonical model for human hypertension, the spontaneously hypertensive rat (SHR). Comparison of cytosine methylation patterns of SHR to the related normotensive Wistar Kyoto rats (WKY) identified thousands of methylation differences between the kidneys of the two strains. Further exploration of the brain and liver of the same animals showed that some of these methylation differences were represented in all three germ layers, and thus hold the potential to be both inborn and transmissible events. Even though the vast majority of differences were located in yet to be annotated regions of the rat genome and could not be explored at this point, at least two candidates for so called “germline epimutations” were identified in Arhgap11a and Tomm20. Neither of the two had previously been linked to hypertension but are involved in biological pathways that can be associated with blood pressure regulation. In a complementary experiment I confirmed that transient exposure to Captopril caused reversion to normotension in the SHR. In contrast to previous reports, lowering of blood pressure was not heritable. However methylationdifferences induced by transient Captopril treatment were subtle and less numerous than those seen in the comparison of WKY and SHR. Nevertheless, hundreds of methylation differences were found and 41 were the same as seen in all three tissues between SHR and WKY. The results of this thesis are consistent with some epigenetic involvement in blood pressure regulation, and provide a platform for future studies into the investigation of the role of epigenetics in human hypertension