Antioxidantes e ácidos graxos poli-insaturados no leite de vacas em lactação em resposta à ingestão de linhaça

• Autor(a) principal: Kazama, Daniele Cristina da Silva
• Data de Publicação: 2009
• 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/1/1500
• topic: Bovino de leite; Comportamento ingestivo; Digestibilidade; Ácidos graxos; Alimento funcional; Nutrição; Vaca em lactação; Casca de linhaça; Enterolactona; Lignanas; Monensina; Sais de cálcio de óleo de linhaça; Brasil.; Bovine milk; Feeding behavior; Digestibility; Fatty acids; Functional food; Nutrition; Lactating cow; Flaxseed hulls; Enterolactone; Lignans; Monensin; Linseed oil calcium salts; Brazil.; Ciências Agrárias; Zootecnia

In vitro and in vivo studies were conduced to evaluate the potential of flaxseed to increase concentration of mammalian lignans in milk. In a first trial, flax seeds and hulls were incubated to determine the in vitro conversion of plant lignans from two flax products (hull and seed) into the mammalian lignans enterolactone and enterodiol by bovine ruminal and fecal microbiota. Plant lignans in flax seeds and hulls averaged 9.2 and 32.0 nmol mg`1, respectively. The highest net production of enterodiol at 72 and 96 h of incubation was obtained with flax hulls incubated with fecal microbiota. There was no difference in net production of enterodiol between flax products within the first 24 h of incubation. ln general, net production of enterolactone over the 96 h time course was significantly higher for flax products incubated with ruminal than with fecal microbiota. Net production of enterolactone at 72 and 96 h of incubation was greater for flax hulls than flax seeds. A second experiment, was conducted in vivo with four lactating Holstein cows assigned to a 4 x 4 Latin square design that were fed one of the four treatments: control with no flaxseed hulls (CO), control with flaxseed hulls (FH), monensin (16 ppm) with no flaxseed hulls (MO), and monensin (16 ppm) with flaxseed hulls (HM). The apparent digestibility of CP was higher for diets containing flaxseed hulls and for diets supplemented with monensin. Significant higher digestibility of ether extract was observed for treatments with flaxseed hulls compared with treatments without flaxseed hulls. Feeding flaxseed hulls increased concentrations of total trans fatty acids (FA), monounsaturated FA, polyunsaturated FA, long-chain FA and n-3 FA, and the polyunsaturated to saturated FA ratio in milk fat. The n- 6 to n-3 ratio in milk fat was lower for cows fed flaxseed hulls compared with those fed no flaxseed hulls. Monensin supplementation increased the concentrations of cis9-l6:l and cis9,l2-18:2 in milk fat. Intake of dry matter (DM) was higher for treatments without flaxseed hulls than for treatments with flaxseed hulls. Moreover, milk production was decreased for cows fed flaxseed hulls. Concentration of enterolactone in both ruminal fluid and milk was higher for cows fed flaxseed hulls compared with those fed no flaxseed hulls. Concentration of ferric reducing antioxidant power was similar among treatments. A third experiment was conducted in vivo with four Holstein cows used in a 4 x 4 Latin square design. The four treatments were: a control diet containing no flaxseed products (CO), 4.l8 g/kg DM of whole flaxseed (WF), 1.87 g/kg DM of calcium salts of flaxseed oil (CF) or a mixture of 2.30 g/kg DM of whole flaxseed and 0.83 g/kg DM of calcium salts of flaxseed oil (MF). Dry matter intake, digestibility, and milk production and composition were similar among treatments except for milk fat percentage that was lower for CF compared to CO with no difference between CF and WF and MF. Concentrations of intermediates of biohydrogenation of FA in the rumen were higher when calcium salts of flaxseed oil were fed, and rumenic acid (cis9,transl l-1822) concentration was higher for CF compared to WF treatment. Milk fat concentration of alpha-linolenic acid was higher for CF and MF than CO, but was similar to WF. Feeding whole flaxseed did not alter enterolactone in milk compare to calcium salts of flaxseed oil. Both ruminal and fecal microbiota are able to transform plant lignans into mammalian lignans. Feeding flaxseed hulls was a good strategy to improve milk FA composition and increase enterolactone concentration in milk. Calcium salts of flaxseed oil depressed milk fat concentration and whole flaxseed had no effect on milk enterolactone concentration.