The compositions and concentrations of lipid classes, fatty acids, tocopherols were determined in the lipids from blue-green microalga Spirulina platensis. Total lipids (TL) recovered using chloroform: methanol (2:1, v/v) were found to be 163.5 g/kg (on dry weight basis). The level of neutral lipids was the highest, followed by glycolipids and phospholipids, respectively. Among TL and lipid classes, palmitic, γ-linolenic and linoleic acids were the dominating fatty acids. Compared to the neutral lipids, the polar fractions were generally characterised by higher percentages of saturated fatty acids. The recovered lipids were characterised by high percentage of tocopherols, wherein α-tocopherol constitutes about 73% of total tocopherols present, the rest being γ-tocopherol. Spirulina platensis lipids exhibited a strong radical scavenging activity towards stable DPPH free radicals, whereas 27% of DPPH radicals were quenched after 2 h incubation. TL and lipid classes inhibited the growth of different microorganisms except gramnegative bacteria. At high concentrations, the tested lipids appeared more effective against a. niger (28.3 ± 1.53 mm). The information obtained in the present investigation is useful for lipid characterisation and further chemical and nutritional investigations of Spirulina platensis.

Key words:Oxidative stress, antioxidants, pneumonia in calves.Pneumonia and pneumoenteritis are the major problems affect health and performance of calves and induce many losses even with treatment. Thirty calves were subjected to study; fifteen calves (group 1) showed fever, cough, bilateral mucopurulent nasal discharges with abnormal lung sound on auscultation. The remained fifteen calves were apparently clinically healthy and kept as control group (group 2). Clinical observation had been done and complete blood picture, oxidant/antioxidant profile and serum sodium, potassium and chloride were evaluated. Results of hematological analysis of group 1 showed a significant reduction in the RBCs count, Hb content, PCV and MCV indicating microcytic hypochromic anemia associated with a non-significant increase in the MCH and significant increase in both of MCHC and WBCs indicating leukocytosis. Results of oxidant/antioxidant profile of group 1 showed a significant reduction in the activity of CAT, SOD, GSH, GSH-Px and TAC values associated with a significant increase in the MDA level. While levels of serum electrolytes of group 1 showed a significant reduction in Na and Cl with a significant increase in K.