Effect of dietary linseed oil and Ganoderma lucidum or olive leaves supplementation on fatty acid composition and oxidative status of rabbits

The aim of the present study was to evaluate the influence of natural antioxidant supplementation on the oxidative stress induced by a high proportion of polyunsaturated fatty acids (PUFA) in rabbit diets. Forty-eight SIKA rabbits (24 male, 24 female) were penned individually and after a 5-d adaptation period divided into 4 homogeneous groups (2.58±0.3 kg). The CONT– group received a diet with 60 g/kg palm fat, while the other 3 groups received a diet with 60 g/kg linseed oil which was either unsupplemented (CONT+) or supplemented with 10 g/kg of Ganoderma lucidum (REISHI) or 10 g/kg of olive leaves (OLIVE). Rabbits were euthanised at 102 d of age, 22 d after the start of the experiment. Live weight, weight gain, feed intake and feed conversion rate were recorded. The fatty acid composition of back (M. longissimus dorsi) and hind leg muscle (thigh muscle), adipose tissue (abdominal fat) and liver were determined. To evaluate the oxidative status of rabbits, the malondialdehyde (MDA) concentration in the plasma, liver and both muscles was measured. DNA damage in the leukocytes was measured. Linseed oil addition increased the PUFA ratio and decreased the proportion of saturated fatty acids in all tissues (P<0.001), with no detrimental effect on productive performance of rabbits compared to palm fat. Linseed oil also reduced n-6/n-3 PUFA ratio in all tissues (P<0.001). However, linseed oil addition increased the oxidative stress by increasing MDA concentrations in the liver and muscles (P<0.001), but did not affect the plasma MDA concentrations and the extent of DNA damage in the blood leukocytes compared to palm fat. Addition of olive leaves tended to decrease the concentration of MDA in the liver Addition of olive leaves tended to decrease the concentration of MDA in the liver compared to CONT+ (P=0.059), with no effect of Ganoderma lucidum.