| This experiment was conducted to investigate the effect of rubber seed oil or flaxseed oil in dairy cow diets on rumen digestion, milk performance, fatty acid composition and oxidation stability of milk fat, fatty acid composition and antioxidant capacity of blood. Forty-eight mid-lactation Holstein dairy cows were randomly assigned to one of four treatments according to a completely randomized block design. Cows were fed a basal diet (Control, CON) or the basal diet supplemented with 4% rubber seed oil (RO),4% flaxseed oil (FO) or 2% rubber seed oil plus 2% flaxseed oil (RFO) on a dry matter (DM) basis for 9 weeks. The results are shown in the below.1. The results showed that feed intake (DMI), milk protein percentage, and milk fat levels did not differ between the treatments. Cows fed the RO, FO or RFO treatments had a higher (P< 0.001) milk yield than the CON group, while milk fat percentages decreased. Compared with the CON, milk concentration of a-linolenic acid (ALA) content was substantially higher in cows receiving RO or RFO and was double in cows receiving FO (P< 0.001). Both C18:1 trans-11(VA) and C18:2 cis-9, trans-11 (CLA) levels were higher (P< 0.001) in cows fed added flaxseed or rubber seed oil. The increase in VA, ALA and CLA was greater in cows fed RFO than in cows fed RO alone. Compared with the CON, the milk fat from cows fed any of the dietary supplements had a higher concentration of unsaturated fatty acids (UFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA); conversely, the saturated fatty acids (SFA) levels in milk fat were 30% lower. The catalase (CAT) activity was decreased (P< 0.05) in FO and RFO groups compared with the CON. The malondialdehyde (MDA) tended to increase (P< 0.10) in RO, FO and RFO treatments compared with the CON.2. The results showed that the pH value, ammonia N, and microbial crude protein (MCP) of ruminal liquid were not affected by rubber seed oil and flaxseed oil supplementation (P> 0.05). The contents of acetate and the rario of acetate to propionate (C2/C3) in the oil supplementation treatments were decreased significantly(P< 0.05) and there were no defference among the oil groups. The total volatile fatty acid (TVFA) was significantly decreased in the RO group(P< 0.05), but there were the tendency of decreased in FO and RFO groups. The contents of acetate, butyrate, isobutyate, and valerate were not affected by rubber seed oil and flaxseed oil supplementation (P> 0.05). The concentration of C8～C18 fatty acid were decreased significantly (P< 0.05); The concentration of oleic acid (t9C18:1, VA, c9C18:1) were higher than the CON (P< 0.05) and the concentration of t9C18:1 and VA in FO and RFO were higher than RO (P< 0.05); The concentration of c9t11 CLA in FO and RFO groups were higher than RO and CON groups (P< 0.05); The content of ALA were increased in RO, FO and RFO treatments, but there were no significant (P> 0.05); The concentration of UFA and MUFA in RO, FO and RFO treatments were higher than the CON (P< 0.05) and it is higher in FO group than the RO (P< 0.05); The concentration of SFA in RO, FO and RFO treatments were decreased than the CON (P< 0.05); The concentration of PUFA were no defference among the FO, RFO and CON treatments, but all higher than the RO group (P< 0.05).3. The results showed that compared with the CON, the RO, FO and RFO groups increased the UFA content and decreased the SFA content in serum (P< 0.05), but the total PUFA content had no change (P> 0.05); All the RO, FO and RFO treatments increased the VA, c9t11 CLA and ALA composition in serum compared with the Control group (P< 0.05); The VA, c9t11 CLA, ALA composition of serum in FO and RFO groups were higher than the RO group(P< 0.05). Insulin and growth hormones were not affected by dietary treatments. However, there was an increase (P< 0.01) in both cholesterol and nonesterified fatty acids (NEFA) levels. The superoxide dismutase (SOD) of serum had no significant differences among the treatments (P> 0.05); The glutathione peroxidase (GSH-Px) in FO and RFO treatments were lower than the Control and RO treatments (P< 0.05); The CAT were decreased in FO and RFO compared with the Control (P< 0.05), but the RO had no significant differences compared with the Control, FO and RFO treatments (P> 0.05); The MDA content in serum in FO and RFO groups were higher than the Control and RO treatments (P< 0.05).These results indicate that a supplement of rubber seed oil and flaxseed oil will increase milk production and the functional fatty acids content (ALA, VA and CLA) in milk fat, while decreasing the content of saturated fatty acids and decreasing the oxidative stability of milk fat; The results also implicated that appropriate dose of rubber seed oil and flaxseed oil supplementation could improve rumen digestion with the pattern of fermentation changed and improve the fatty acid by enhancing the VA, CLA and ALA composition in rumen fluid and serum. The rubber seed oil have no effect on antioxidant capacity of serum, but the flaxseed oil could decrease the antioxidant capacity of serum. |
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