Animal mortality

About: Animal mortality is a research topic. Over the lifetime, 526 publications have been published within this topic receiving 14887 citations.

Ecological guidelines for waterpoints in extensive protected areas

Abstract: Augmenting natural water supplies by providing artificial waterpoints is an intervention commonly adopted by managers of national parks and other large protected areas. Contrasting policies are currently being followed in three of the premier national parks in southern Africa. Some empirical guidelines for waterpoint provision are suggested by case histories of these and other wildlife reserves. A geometric model, based on the rotation of water-dependent herbivores between wet season and dry season ranges, is outlined to indicate the appropriate spacing between perennial waterpoints. The aim is to apportion vegetation impacts evenly between these ranges, and allow plants a period of recovery from severe grazing pressure. The model suggests that a much wider spacing between perennial water sources is advisable than is currently operative in most conservation areas. Seasonal waterpoints reduce the period of concentration near perennial water, but prolong use of vegetation in the wet season range. Excessive waterpoints (1) favour water-dependent ungulates and elephants at the expense of rarer ungulates, (2) increase predator impacts on prey populations, (3) widen vegetation degradation, (4) worsen animal mortality during droughts, (5) decrease ecosystem stability, and (6) lead to a loss of biodiversity.

Gymnodinium Brevis Sp. Nov., A Cause of Discolored Water and Animal Mortality in the Gulf of Mexico

Abstract: I. DEAN, B. E. Effect of soil type and aeration upon root systems of certain aquatic plants. Plant Physiol. 8: 203-2 2 2. I 9^33 . 2. DITTMER, H. J. A quantitative study of the roots and root hairs of a winter rye plant (Secale cereale). Amer. Jour. Bot. 24:4I7-420. I937. 3. . The efficiency of monocotyledon roots in soil conservation. Univ. Iowa Nat. Hist. Stud. I 7 343-346* I 938. . A quantitative study of the subterranean members of three field grasses. Amer. Jour. Bot. 25 :654-657 I938S. KRAMER, P. J. Water made available by root extension. Plant Physiol. I5: 743-747. I940. 6. PAVLYCHENKO, T. K. Quantitative studies of the entire root systems of weed and crop plants under field conditions . Ecology I 8:6 2-79 . I 93 7.

Causes of mortality in laying hens in different housing systems in 2001 to 2004

Abstract: The husbandry systems for laying hens were changed in Sweden during the years 2001 – 2004, and an increase in the number of submissions for necropsy from laying hen farms was noted. Hence, this study was initiated to compare causes of mortality in different housing systems for commercial laying hens during this change. Based on results from routine necropsies of 914 laying hens performed at the National Veterinary Institute (SVA) in Uppsala, Sweden between 2001 and 2004, a retrospective study on the occurrence of diseases and cannibalism, i.e., pecking leading to mortality, in different housing systems was carried out. Using the number of disease outbreaks in caged flocks as the baseline, the expected number of flocks with a certain category of disease in the other housing systems was estimated having regard to the total number of birds in the population. Whether the actual number of flocks significantly exceeded the expected number was determined using a Poisson distribution for the variance of the baseline number, a continuity correction and the exact value for the Poisson distribution function in Excel 2000. Common causes of mortality in necropsied laying hens included colibacillosis, erysipelas, coccidiosis, red mite infestation, lymphoid leukosis and cannibalism. Less common diagnoses were Newcastle Disease, pasteurellosis and botulism. Considering the size of the populations in the different housing systems, a larger proportion of laying hens than expected was submitted for necropsy from litter-based systems and free range production compared to hens in cages (P < 0.001). The study showed a significantly higher occurrence of bacterial and parasitic diseases and cannibalism in laying hens kept in litter-based housing systems and free-range systems than in hens kept in cages (P < 0.001). The occurrence of viral diseases was significantly higher in indoor litter-based housing systems than in cages (P < 0.001). The results of the present study indicated that during 2001–2004 laying hens housed in litter-based housing systems, with or without access to outdoor areas, were at higher risk of infectious diseases and cannibalistic behaviour compared to laying hens in cages. Future research should focus on finding suitable prophylactic measures, including efficient biosecurity routines, to reduce the risk of infectious diseases and cannibalism in litter-based housing systems for laying hens.

Pulmonary physiological and surfactant changes during injury and recovery from hyperoxia.

Abstract: The time course of lung injury and recovery from a sublethal exposure to 100% O2 was investigated in adult rabbits. Animals were exposed to 100% O2 for 64 h and then returned to room air for varying periods of time up to 200 h. By the end of the exposure period, the alveolar permeability to solute increased significantly, and biochemical analyses of bronchoalveolar lavages showed a 30% decline in phospholipid content and a threefold increase in protein levels. However, other parameters such as wet-to-dry lung weight ratios, blood gas values, and pressure-volume mechanics were not significantly different from control levels after 64 h of hyperoxia. Twenty-four hours postexposure, alveolar phospholipid levels had declined even further (51% of control), and mean protein levels in lavage increased to eight times control values. These lavages exhibited severely impaired dynamic surface activity at 37 degrees C and 100% humidity in an oscillating bubble apparatus. In addition, total lung capacity, lung compliance, and arterial O2 partial pressure declined greatly at this time. Between 12 and 48 h postexposure, animal mortality was 35%; the remaining animals survived, and physiological parameters returned to normal by 200 h postexposure. Bronchoalveolar lavages from the recovered animals contained protein levels equal to those of controls and phospholipid levels approximately twice those in control lavages. Lavage surface activity also returned to normal by the 200 h postexposure time point.

Heat Shock Protein 20 Interacting With Phosphorylated Akt Reduces Doxorubicin-Triggered Oxidative Stress and Cardiotoxicity

Abstract: Doxorubicin (DOX) is a widely used antitumor drug, but its application is limited because of its cardiotoxic side effects. Heat shock protein (Hsp)20 has been recently shown to protect cardiomyocytes against apoptosis, induced by ischemia/reperfusion injury or by prolonged beta-agonist stimulation. However, it is not clear whether Hsp20 would exert similar protective effects against DOX-induced cardiac injury. Actually, DOX treatment was associated with downregulation of Hsp20 in the heart. To elucidate the role of Hsp20 in DOX-triggered cardiac toxicity, Hsp20 was first overexpressed ex vivo by adenovirus-mediated gene delivery. Increased Hsp20 levels conferred higher resistance to DOX-induced cell death, compared to green fluorescent protein control. Furthermore, cardiac-specific overexpression of Hsp20 in vivo significantly ameliorated acute DOX-triggered cardiomyocyte apoptosis and animal mortality. Hsp20 transgenic mice also showed improved cardiac function and prolonged survival after chronic administration of DOX. The mechanisms underlying these beneficial effects were associated with preserved Akt phosphorylation/activity and attenuation of DOX-induced oxidative stress. Coimmunoprecipitation studies revealed an interaction between Hsp20 and phosphorylated Akt. Accordingly, BAD phosphorylation was preserved, and cleaved caspase-3 was decreased in DOX-treated Hsp20 transgenic hearts, consistent with the antiapoptotic effects of Hsp20. Parallel ex vivo experiments showed that either infection with a dominant-negative Akt adenovirus or preincubation of cardiomyocytes with the phosphatidylinositol 3-kinase inhibitors significantly attenuated the protective effects of Hsp20. Taken together, our findings indicate that overexpression of Hsp20 inhibits DOX-triggered cardiac injury, and these beneficial effects appear to be dependent on Akt activation. Thus, Hsp20 may constitute a new therapeutic target in ameliorating the cardiotoxic effects of DOX treatment in cancer patients.