Hepatosis diaetetica in pigs

Extract

Hepatosis diaetetica of pigs (nutritional liver necrosis, toxic liver dystrophy, etc.) is a disease entity characterized by necrosis of parenchymal cells without any particular distribution within the liver. It has long been known that it could be produced by adding cod liver oil to the diet and prevented by adding vitamin E. Nutritional liver necrosis in the pig is now known to be one of the many manifestations of deficiency of vitamin E (α-tocopherol) and/or selenium which occur in numerous animal species. Some of these conditions are: white muscle disease (nutritional muscular dystrophy or degeneration) which is known in all the domestic and many non-domestic species; dietetic microangiopathy (mulberry heart) of pigs; exudative diathesis and encephalomalacia of chickens ; yellow fat disease of pigs, rats and mink ; oesophago-gastric ulcers in pigs.     

Muscle degeneration and yellow fat disease in foals

Extract

The annual yield of lambs from a breeding flock is usually the major factor determining the success of a sheep farm. It is therefore surprising to find how many flocks are apparently reproclucing at a rate far below their genetic potential. There are many points at which the complicated and extended process of reproduction can be clistubed. Limiting factors fall into three main classes, (a) genetic limitations, (b) infective processes, (c) environmental factors (seasonal changes, environmental stresses and nutrition). At present knowledge of these influences is far from complete but it is most encouraging that research is being undertaken in many countries and progress is rapid. There is no reason to doubt that notable improvement could be made in many districts, but it must be stressed that it is difficult or even impossible to exploit all favourable influences; for example, the best time for mating may imply an unfavourable time for lambing or weaning; or market considerations may override physiological desiderata. It is obvious that in each district the pros and cons must be carefully weighed to select the most profitable combination of husbandry procedures; this can be clone rationally only on the basis of a great deal of knowledge.     

Effectiveness of a barrier wall and culverts in reducing wildlife mortality on a heavily traveled highway in Florida

Because of high numbers of animals killed on Paynes Prairie State Preserve, Alachua County, Florida, the Florida Department of Transportation constructed a barrier wall-culvert system to reduce wildlife mortality yet allow for passage of some animals across the highway. During a one year study following construction, we counted only 158 animals, excluding hylid treefrogs, killed in the same area where 2411 road kills were recorded in the 12 months prior to the construction of the barrier wall-culvert system. Within the survey area lying directly in Paynes Prairie basin, mortality was reduced 65% if hylid treefrogs are included, and 93.5% with hylid treefrogs excluded. Sixty-four percent of the wildlife kills observed along the barrier wall-culvert system occurred at a maintenance road access point and along 300 m of type-A fence bordering private property. The 24 h kill rate during the post-construction survey was 4.9 compared with 13.5 during the pre-construction survey. We counted 1891 dead vertebrates within the entire area surveyed, including the ecotone between the surrounding uplands and prairie basin which did not include the barrier wall and culverts. Approximately 73% of the nonhylid road kills occurred in the 400 m section of road beyond the extent of the barrier wall-culvert system. We detected 51 vertebrate species, including 9 fish, using the 8 culverts after the construction of the barrier wall-culvert system, compared with 28 vertebrate species in the 4 existing culverts prior to construction. Capture success in culverts increased 10-fold from the pre-construction survey to the post-construction survey. Barrier wall trespass was facilitated by overhanging vegetation, maintenance road access, and by the use of the type-A fence. Additional problems resulted from siltation, water holes, and human access. These problems could be corrected using design modifications and by routine, periodic maintenance.     

Fibrin–alginate hydrogel supports steroidogenesis,in vitro maturation of oocytes and parthenotes production from caprine preantral follicles cultured in group

This study aimed to establish a culture system that improves the in vitro development of caprine preantral follicles. In a first experiment, follicles were encapsulated as a single unit per bead and cultured singly or in groups or with five follicles in the same alginate (ALG) bead for 18 days. In a subsequent experiment, the “five follicles per bead” design was chosen to culture in ALG, fibrin–alginate (FA) or hyaluronate (HA) for 18 days. In a third experiment, we chose the five follicles per bead in FA to culture for 30 days. The culture set‐up of five follicles per ALG bead increased antrum formation and follicle diameter compared to the other culture designs (p < .05). Moreover, under this condition, 44.44% of the oocytes from in vitro cultured preantral follicles reached meiotic resumption. A significant increase of follicle diameter occurred in attachment system and FA (p < .05), but the ALG condition reached the highest among all groups on day 18 (p < .05). Follicles encapsulated in matrix produced more estradiol and progesterone than attachment system (p < .05). The expression of MMP‐9 mRNA was higher in FA than in other groups (p < .05) and similar to antral follicles from in vivo control (p > .05). Only FA group resulted in oocytes matured. After 30 days, oocytes from preantral follicles in vitro grown in FA developed to eight‐cell parthenotes. In conclusion, a culture system using FA supported the development of caprine preantral follicles cultured in group and included in the same bead of hydrogel, improving the oocyte maturation and producing parthenotes.     

Two Methods of Vitrification Followed by In Vitro Culture of the Ovine Ovary: Evaluation of the Follicular Development and Ovarian Extracellular Matrix

The aim of this study was to evaluate the influence of two vitrification techniques on the extra cellular matrix (ECM) and ovarian follicular development. The ovarian cortex was fragmented (9 mm³) and divided into six groups, viz. fresh control, cultured control, vitrified by the Ovarian Tissue Cryosystem (OTC) method, conventional solid surface vitrification (SSV) method, OTC/cultured and SSV/cultured. Follicles from all the fragments were analysed for morphology, development and viability. The ECM was evaluated based on the condition of collagen and reticular fibres and the immunolocalization of type I collagen and fibronectin. After 7 days of culture, the tissue vitrified by OTC revealed a higher percentage (p < 0.05) of morphologically normal (30.66%) and viable (60.00%) follicles when compared with those vitrified using the SSV technique (21.33% and 23.00%). In all the fragments cultured, regardless of the vitrification method, a significantly higher percentage of developing follicles was observed when compared with the non‐cultured tissue. Analysis of the type I collagen showed increased immunostaining after the in vitro culture in the vitrified fragments. In conclusion, the OTC is better for preserving the follicular viability and morphology and maintaining the integrity of the extracellular matrix components of the ovine ovary.     

Predicting the changes in environmentally and agronomically significant phosphorus forms following the cessation of phosphorus fertilizer applications to grassland

Phosphorus (P) loss from soil can impair surface water quality. Losses from soil are related to soil P concentrations, but agronomic measures such as Olsen P do not in many cases predict the potential for P loss. One possible strategy to decrease P loss is to stop applying P fertilizers. We examined the changes in both agronomic (Olsen P) and environmental [water‐extractable P (WEP) and calcium chloride‐extractable P (CaCl₂‐P)] P tests, and the potential implications following a halt to P fertilizer application to four long‐term grassland field trials on different soil types. Exponential decreases in Olsen P and WEP concentration over time were observed in three of the four trials, but only in one trial for CaCl₂‐P. The rates of decrease in Olsen P (OP) and WEP concentration were best correlated with initial WEP (WEP_i) concentration and the quotient of Olsen P_i/P retention (PR, a measure of Al‐ and Fe‐oxides), respectively. The equation t = 1/(?0.035 × ln OP_i/PR ? 0.0455) × (ln WEP_t ? ln WEP_i) was used to predict the time (t) taken for WEP concentrations at the sites to decrease to 0.02 mg/L (WEP_t), which is proposed as a limit for dissolved reactive phosphorus in overland flow, and the result was 23–44 yr. Results from a similar equation for Olsen P predicted a quicker rate of WEP. A significant decline in dry matter (DM) yield was observed at one trial site. For this site, the rate of decline in DM yield was of a similar magnitude to the rate of decline in WEP concentration. This suggests that halting P fertilizer application to decrease P loss as measured by WEP concentration may decrease farm productivity. An alternative, more financially acceptable, strategy is required, such as a negative P balance while maintaining yields with N fertilizer, but further work is required to assess both the agronomic and environmental implications of this strategy.     

Forgotten fishes: What is the future for small threatened freshwater fish? Population risk assessment for southern pygmy perch,Nannoperca australis

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The effects of allopurinol on the ultrastructure of ischaemic and reperfused large intestine of sheep

Objective To test the possible inhibitory effect of allopurinol on reperfusion injury, caused by oxygen-derived free radicals, of sheep large intestine.
Design An ultrastructural study on caecal tissues from control and treated groups.  

Animals

Fifty sheep in four ischaemic and reperfused (treatment) groups and one control group. Three of the treatment groups were subdivided for half to be injected with allopurinol and the other half with its solvent, potassium hydroxide (KOH).
Procedure Ischaemia of the caecum was induced in the four treatment groups for 60 minutes by clamping the apex. Allopurinol and its KOH solvent were injected intravenously in three treatment groups prior to ischaemia. Samples were collected before and 1 hour after induction of ischaemia and 1 min, 1 h and 8 h after reperfusion. Tissues were processed and examined with an electron microscope.
Results Untreated and solvent injected sheep showed minor ultrastructural changes following ischaemia. With reperfusion, there was severe mitochondrial, goblet cell and basement membrane damage. Tissues from allopurinoltreated sheep were preserved and appeared similar to tissues from the control group.  

Conclusion:

Pre-treatment with allopurinol prevented damage to tissues whereas untreated or allopurinol solventtreated showed severe damage following reperfusion. It is believed that allopurinol, an analogue of hypoxanthine and xanthine, prevents reperfusion injury by competitively binding with xanthine oxidase. This reduces or inhibits the xanthine oxidase mediated conversion of hypoxanthine to xanthine thereby preventing the formation of oxygen-derived free radicals.