Effect of antioxidants on oxidative stability of edible fats and oils: thermogravimetric analysis

Thermogravimetric analysis was used to determine the oxidative stability of various edible oils (olive oil, milkfat) and triacylglycerides (triolein, trilinolein), while the effect of natural (alpha-tocopherol, ascorbic acid) and synthetic antioxidants (butylated hydroxytoluene (BHT), butylated hydroxyanisole (BHA), and tertiary butyl hydroquinone were evaluated by addition to trilinolein. Oil resistance to oxidation was obtained by measuring the increase in sample weight due to the uptake of molecular oxygen, the temperature at maximum sample weight, and the temperature at the onset of oxidation. When comparing sample weight increase, trilinolein proved to be oxidatively less stable than triolein, olive oil, and milk fat, while triolein was less stable than olive oil and milk fat. Olive oil showed significantly higher stability than milkfat when comparing the temperature at the onset of oxidation. When comparing effectiveness of antioxidants, a combination of 0.01% BHA and 0.01% BHT increased trilinolein stability the most.     

Evidence that nitric acid increases relative humidity in low-temperature cirrus clouds

In situ measurements of the relative humidity with respect to ice (RHi) and of nitric acid (HNO3) were made in both natural and contrail cirrus clouds in the upper troposphere. At temperatures lower than 202 kelvin, RHi values show a sharp increase to average values of over 130% in both cloud types. These enhanced RHi values are attributed to the presence of a new class of HNO3-containing ice particles (Delta-ice). We propose that surface HNO3 molecules prevent the ice/vapor system from reaching equilibrium by a mechanism similar to that of freezing point depression by antifreeze proteins. Delta-ice represents a new link between global climate and natural and anthropogenic nitrogen oxide emissions. Including Delta-ice in climate models will alter simulated cirrus properties and the distribution of upper tropospheric water vapor.     

Dynamics of free amino acids in the hemolymph of Pacific whiteleg shrimp Litopenaeus vannamei exposed to different types of stress

We analyzed the dynamics of amino acids, ammonia-N, and carbohydrates in hemolymph when Pacific whiteleg shrimp Litopenaeus vannamei was subjected to air-exposure and low-salinity stresses. Glycine, l-arginine, and d- and l-alanine levels in hemolymph were increased under both stress conditions. Ammonia-N, a product of amino acid catabolism, also increased in level. These results suggest that the above-mentioned amino acids are used as energy sources. Levels of total carbohydrates, the sum of glucose and other carbohydrates, in the hemolymph showed different dynamics between the two types of stress and were not always high. This suggests that other energy sources, such as amino acids, are important when animals are subjected to stress. It is possible that particular amino acids act as energy sources under various stress conditions.     

Prevalence and intensity of non-strongyle intestinal parasites of horses in northern Queensland

A quantitative post-mortem study of 57 horses from northern Queensland was done to determine the prevalence and intensity of non-strongyle intestinal parasites. The following species (% prevalence) were found: Draschia megastoma (39%); Habronema muscae (43%); Gasterophilus intestinalis (34%), G. nasalis (30%); Parascaris equorum (15%); Strongyloides westeri (6%); Probstmayria vivipara (2%); Oxyuris equi (26%); Anoplocephala magna (2%); A. perfoliata (32%). Mean parasite numbers of individual species ranged from 10 to 1310. Prevalence and intensity data were compared to recent studies in Western Australia and in the United States of America. Differences between stabled and paddocked horses were noted, particularly for botfly larvae and spiruroids. Climatic and seasonal changes in prevalence were restricted to H. muscae, G. nasalis and P. equorum with highest prevalence in the wet season or in horses from wet coastal areas. Only P. equorum showed any age effect being restricted to horses less than 5 years old. Breed and sex of horses was not important. The likelihood of changing parasite population dynamics with improved anthelmintic regimen is discussed.     

Strategic use of crutching and dicyclanil to protect unmulesed sheep against breech strike

Objective   To test strategies for the application of dicyclanil and mid-season crutching to maximise protection of unmulesed sheep against breech strike.
Procedure   Three hundred and eighty unmulesed Merino weaners were randomly allocated to four groups either left untreated or treated by different strategies with 50 g/L dicyclanil. Treatments included breech treatment alone and breech plus body treatment, with two application times, immediately after shearing and 6 weeks after crutching or shearing. To assess protection, larval implants with newly hatched Lucilia cuprina larvae were applied to 10 different sheep from each group at 3, 4, 5 and 6 months after crutching and shearing and assessed for the development of strike at 48 hours. The concentration of dicyclanil was measured in wool samples clipped from the breeches of the test sheep.
Results   All dicyclanil treatments gave significant reduction in strike in comparison to controls up until 4 months after crutching but protection in the sheep treated immediately after shearing had waned at 5 months. Treating at 6 weeks after crutching provided significant reduction ( P < 0.05) in strike for 6 months. Results for strike incidence immediately after shearing and concentration of dicyclanil in the breech wool also suggested improvements in protection by delaying treatment for 6 weeks.
Conclusion   In most environments it should be possible to protect unmulesed sheep against breech strike with a carefully planned integrated control program incorporating strategically timed crutching, shearing and dicyclanil application. Delaying treatment with dicyclanil to at least 6 weeks after shearing or crutching increased the protection provided in comparison to treatment immediately after shearing.