Proportion Of Polyunsaturates Research Articles

Viability, susceptibility to peroxidation and fatty acid composition of boar semen during liquid storage.

The changes in viability, susceptibility to peroxidation and fatty acid composition of total phospholipid were studied in boar spermatozoa during 5 day liquid storage in a standard or alpha-tocopherol (alphaT) enriched diluent. The sperm rich fraction of the ejaculates was collected from 6-month old boars. Sperm viability progressively decreased during storage and alphaT inclusion into the diluent significantly inhibited this trend. alphaT inclusion also decreased significantly peroxidation (TBARS production of spermatozoa). Spermatozoa stored in the treatment diluent became rapidly enriched in alphaT with a concomitant decrease of alphaT content in the medium. The proportion of polyunsaturates, mainly 22:6n-3, decreased with a complementary increase in the content of the saturates, mainly 18:0. The inclusion of alphaT into the diluent was effective in totally preventing the significant decrease of 22:6n-3 observed in sperm phospholipid in the control samples during the storage period. It is concluded that the alphaT inclusion in the boar semen diluent increased cell viability through its prevention of an oxidative reduction in the levels of the major polyunsaturated fatty acids, namely 22:6n-3.

Changes in desaturase activity and the fatty acid composition of microsomal membranes from liver tissue of thermally-acclimating rainbow trout

Rainbow trout (Salmo gairdneri) were acclimated to either 5 or 20°C, and then transferred to the opposite temperature, and changes in the fatty acid composition of liver microsomal membranes and the activities of the hepatic Δ9, Δ6, and Δ5 desaturases were measured at intervals of up to one month post-transfer. Inital changes (days 0–3) in fatty acid composition were: (1) an increase in the proportion of saturates and a decrease in the proportion of polyunsaturates during warm acclimation, and (2) a decrease in the proportion of saturates during cold acclimation. The activity of the Δ6 desaturase approximately doubled immediately following the changes in temperature, but alterations in Δ9 and Δ5 desaturase activities required at least 3 days to occur. The results indicate that desaturase enzymes do not play a major role in the initial adaptation of membrane fatty acid composition to changes in temperature. However, the desaturase enzymes may be involved in the later stages (3–28 days) of the acclimatory process. The proportion of monoenes was well correlated with Δ9 desaturase activity during both transfers, and appeared to be adjusted as required to offset changes in the proportion of polyunsaturates.

Effect of Various Endosperm Mutants on Oil Content and Fatty Acid Composition of Whole Kernel Corn (Zea mays L.)1

Abstract Oil content as extracted with chloroform - methanol ranged from 5.2 to 18.4% among the 12 mutant genotypes examined. GLC analysis of the methyl esters of the corn oil fatty acids showed widely significant differences in composition among the genotypes. Action of the opaque-2 gene on the inbred caused the greatest decrease in oil content and greatest increase in the proportion of polyunsaturates. The brittle-2 gene caused the greatest increase in oil content and greatest decrease in the proportion of polyunsaturates. A positive relationship was evident between saturated and oleic acids and oil content. An inverse relationship was evident between polyunsaturated acids and oil content.