Ácidos graxos do leite, expressão gênica e atividade de enzimas antioxidantes em vacas leiteiras alimentadas com fontes de ácidos graxos poli-insaturados

• Autor(a) principal: De Marchi, Francilaine Eloise
• Data de Publicação: 2013
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Estadual de Maringá (RI-UEM)
• Texto Completo: http://repositorio.uem.br:8080/jspui/handle/1/1518
• topic: Canola; Vaca leiteira; Qualidade do leite; Estresse oxidativo; Alimento; Girassol; Linhaça; Superóxido dismutase; Glutationa peroxidase; Catalase; Brasil.; Canola; Milky cow; Quality of milk; Oxidative stress; Food; Sunflower; Flaxseed; Superoxide dismutase; Glutathione peroxidase; Catalase; Brazil.; Ciências Agrárias; Zootecnia

To study the lipid composition of milk were performed three experiments: the first study aimed to evaluate the effect of pelleting and monensin addition on intake, digestibility of nutrients and blood parameters of cows on pasture and supplemented with concentrated containing canola seeds. In the second study the goal was to evaluate the chemistry and lipid composition of milk as well as the butter spreadability of cows on pasture and supplemented with concentrated containing canola seeds. The third study aimed to evaluate the effect of flax meal (FM) addition in the concentrate and sunflower oil (SO) infused into the abomasums on antioxidant enzymes activity of blood and mammary tissue, and gene expression on mammary tissue of lipogenic and antioxidants genes. For the first and second study were used four primiparous Hostein cows, with 135+ 64 d in milk and 449.75 + 5,3 kg of body weight. Cows were assigned to a 4 × 4 Latin square with periods of 21 d. The concentrates evaluated were: 1) corn, soybean meal, vitamin and mineral supplement and ground canola seed (CM); 2) concentrate CM with addition of monensin (CMO); 3) concentrate CM pelleted (CPE) and 4) concentrate CM with addition of monensin and pelleted (CMP). In the third study eight lactating Holstein cows fitted with ruminal cannulas were assigned to a replicated 4 × 4 Latin square with a 2 × 2 factorial arrangement of treatments and four 21 d periods balanced for residual effect. The experimental treatments were: 1) no FM in the diet (control); 2) diet containing 13.7 g/kg FM; 3) no FM in the diet and 250 g SO/d infused in the abomasum; 4) diet containing 13.7 g/kg FM and 250 g SO/d infused in the abomasum. The results showed that the pelletization tended to reduce the fed intake of dry matter (DM), neutral detergent fiber (NDF) and organic matter (OM); and reduced the intake of ether extract (EE) and acid detergent fiber (ADF) in 27% and 26.83%, respectively. The ADF digestibility was reduced by pelletization and there were no effects of monensin on apparent digestibility of nutrients and on blood parameters. The pelletization and monensin did not alter the production and composition of milk. Addition of monensin improved the concentration of PUFA, the ratio of PUFA/SFA and the milk concentration of omega 6. Pelletization improved the concentration of MUFA, the ratio of PUFA/SFA and the ratio of omega 6/omega 3 of milk and, reduced the concentration of SFA. The physical characteristics of butter did not change by the diets evaluated. In the first two studies it was concluded that the use 31.54 g/kg of monensin to cows maintained on pasture do not alter the intake, the digestibility and blood parameters of animals and, the pelletization reduces the EE and ADF intake, and also reduces the ADF digestibility of concentrates with ground canola seeds. The monensin addition and the pelletization of the concentrate improves the fatty acid profile of milk without changing the production and milk composition. Finally, the results of the third study showed that FM improved the CAT activity in erythrocytes in the absence of SO, and this effect was absent when the SO was infused into the abomasums. There was a tendency for a reduction in the mRNA abundance of the NF-kB1 in mammary tissue from cows fed with FM, and mRNA abundance of the SOD2 in mammary tissue tended to improve when SO was infused in absence of FM. FASN, LPL and SCD tended to decrease with SO infusion and in absence of FM in the diet; SO infusion decreased the abundance of PPARγ1 in absence of FM and SREBP1 was decreased by SO infusion. PPARγ2 was greater when cows were fed diet without FM and SO infusion. In conclusion, 13.7 g/kg FM not induce changes in antioxidants enzymes of dairy cows that are infused in the abomasum with 250 g SO/d. No significant changes were observed in mRNA abundance of antioxidant enzymes in mammary gland. SO infusion induce inhibitions in the lipogenic-related genes.