This study investigated the effects of different n-6:n-3 polyunsaturated fatty acid (PUFA) ratios in pig diets using vegetable oil supplementation on growth performance, carcass characteristics, meat quality, and fatty acid composition in the longissimus dorsi muscle (LM) and subcutaneous adipose tissue (SAT) of pigs. Fifty-four cross-bred growing pigs (Large White χ Landrace χ Duroc; 45.03 ± 1.72 kg) were randomly assigned to one of three isoenergetic diets: the 1) basal diet (control), 2) RAPO diet (diet supplemented with 4.5% rapeseed oil), and 3) MIXO diet (diet supplemented with 2.25% rapeseed oil and 2.25% linseed oil), with n-6:n-3 PUFA ratios of approximately 13:1, 7:1, and 2:1, respectively. The experiment lasted 42 days. The RAPO and MIXO diets did not affect the growth performance and carcass characteristics of pigs, while the content of low-density lipoprotein (LDL), triglycerides (TGs), and glucose (GLU) in the serum decreased substantially. Intramuscular fat (IMF) content increased by 19.25% and 20.11% in the LM of pigs fed the RAPO and MIXO diets, respectively, and lower cooking loss and drip loss of meat were observed only in pigs fed the MIXO diet. The RAPO and MIXO diets decreased the stearic acid and palmitoleic acid levels, increased the total PUFA levels (including those of α-linolenic and linoleic acid), and decreased the n-6:n-3 PUFA ratios in LM and SAT. However, the MIXO diet was more effective in improving the fatty acid composition. A mixed oil diet with an n-6:n-3 PUFA ratio of 2:1 is an effective measure for improving meat quality.

RESUMO: O efeito de atrazina e mesotrione e da atividade conjunta de atrazina mais mesotrione no pigmento, n a peroxidação lipídica e na atividade da enzima antioxidante foi estudado. Os tratamentos com atrazina e mesotrione reduziram significativamente as concentrações de clorofila a (Clf a), de clorofila b (Clf b), de carotenoides e o teor de proteína em plantas de grama-seda (Cynodon dactylon L.), mas aumentaram significativamente a peroxidação lipídica. O tratamento com atrazina mais mesotrione causou maior efeito fitotóxico na grama-seda do que o herbicida isolado, o que foi evidenciado pela diminuição significativa da estabilidade da membrana em função dos teores de oxigênio singlete e malondialdeído (MDA), bem como pela maior redução dos teores de Clf a, Clf b e carotenoides. Embora a grama-seda ativasse as enzimas antioxidantes catalase (CAT), peroxidase (POD) e glutationa S-transferase (GST), ela foi significativamente danificada após os tratamentos com herbicidas. Assim, os resultados sugerem que os antioxidantes enzimáticos e não enzimáticos da grama-seda foram sobrecarregados após o tratamento com atrazina mais mesotrione, e as espécies reativas de oxigênio (ERO) causaram peroxidação lipídica, degradação de pigmentos e proteínas, além de outros danos a constituintes celulares.

ABSTRACT: The effect of atrazine, mesotrione, and joint activity of atrazine plus mesotrione on pigment, lipid peroxidation, and antioxidant enzyme activity was studied. Atrazine and mesotrione treatments significantly reduced chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoid concentrations, and protein content in bermudagrass (Cynodon dactylon L.) plants, whereas they significantly enhanced lipid peroxidation. The treatment of atrazine plus mesotrione caused greater phototoxic effect on bermudagrass than either herbicide alone, which was evident from the significantly decreased membrane stability noted as a function of the enhanced singlet oxygen and malondialdehyde (MDA) contents, as well as from the greater reduction in Chl a, Chl b, and carotenoid contents. Although bermudagrass activated the antioxidant enzymes catalase (CAT), peroxidase (POD), and glutathione S-transferase (GST), it was significantly injured after the herbicide treatments. Thus, results suggested that the enzymatic and non-enzymatic antioxidants of bermudagrass was overloaded after the treatment of atrazine plus mesotrione, and the reactive oxygen species (ROS) subsequently caused lipid peroxidation, pigment and protein degradation, as well as other cellular constituent damage.

Higher olefins are produced as a by product in a number of refinery processes and are one of the potential raw materials to produce propylene. In the present study, FCC model feed compound was considered to explore the olefin cracking features and options to enhance propylene using 30% SAPO-34 zeolite as catalyst in a micro-reactor. The superior selectivity of propylene (73 wt%) and higher total olefin selectivity was obtained over 30% SAPO-34 catalyst than over Y or ZSM-5 zeolite catalysts. The thermodynamical constraints were found to be relatively less serious in the case of 1-hexene conversion. Most of the 1-hexene follows a direct cracking pathway to give two propylene molecules, due to weak acid sites and better diffusion opportunities. The higher temperature and short residence time could also suppress the hydrogen transfer reactions. From OPE (olefins performance envelop) the products were classified as primary, secondary, or both. Iso-hexene (2-methyl-2-pentene) cracking was also analyzed in order to justify a shape selective effect of the SAPO-34 catalyst. A detailed integrated reaction network together with an associated mechanism was proposed and discussed in detail for their fundamental importance in understanding the olefin cracking processes over SAPO-34.