effect of feeding oxidized soybean oil against antioxidant role of pomegranate seed on physiology and metabolism of periparturient saanen goats

introduction oxidative stress is metabolic and physiologic status caused by imbalance between free radical production and antioxidant defense of body. in some physiological status such as rapid growth, parturition, disease and high production rate that imbalance would occur. high producing dairy animals are suspected to oxidative stress and require to antioxidant supplementation. negative energy balance in early lactation force the nutrition specialist to apply oil and high nfc diet to exceed the requirement of high producing dairy animals such as holstein cows and saanen goats. in recent years, the attention to the use of herbal or organic antioxidant in animal nutrition has increased. this study was carried out to investigate the effects of feeding oxidized soybean oil (oso) plus pomegranate seed (ps) as a natural antioxidant, on metabolism and physiology of preparturient saanen goats. materials and methods eighteen saanen dairy goats with initial body weight of 47 ± 9 kg were assigned to three dietary treatments in a completely randomized design with repeated measurements for 21 days before anticipated parturition. experimental treatments including: 1) base diet and 4% fresh soybean oil (fso), 2) base diet and 4% oxidized soybean oil (dm basis) respectively, and 3) base diet plus 4% oso and 8% pomegranate seed (oso-ps). after 2 weeks of feeding trial diets, goats were sampled for blood, rumen liquor, faeces and urine for measuring parameters of blood glucose, bhba, lipid and nitrogen profile, rumen liquor ammonia nitrogen, urine ph and volume, faeces qualitative and quantitative variables and other responses such as nutrients digestibility. the glm procedure of sas software v.9.2 were used for statistical analysis. initial body weight and metabolic variables were used as covariate in the model. results and discussion all nutrients digestibility, ruminal ammonia nitrogen and voluntary feed intake were decreased by oso (p<0.05) and increased significantly by oso-ps vs. fso. urinary ph was significantly decreased by oso-ps in comparison with other treatments. urinary volume was increased (p<0.05) and the faeces bolus volume and humidity significantly reduced by oso vs. other treatments. triiodothyronine and creatinine concentration were significantly decreased by oxidized soybean oil (treatment 2) and oso-ps (treatment 3) compared to sham control (fso), and fasting glucose was significantly decreased and increased by oso and oso-ps vs. fso (p<0.05), respectively. the metabolism of all types of cholesterol was significantly altered by the treatments but the fluctuations of other parameters were not significantly differed among diets. this result is in accordance with other studies on herbal antioxidant feeding to ruminant, but the difference is in study situation of stimulated oxidative stress in this trial. its might be suggested that antioxidant capacity of pomegranate seed could be an effective agent on saving turnover rate of epithelium against free radicals and other lipid peroxides. conclusion generally, oxidative stress metabolic signs and statues were stimulated by oso but most metabolic and physiological indices were improved by hormonal and antioxidant effects of ps. improved nutrients digestibility, blood parameters, urine and faces variables and rumen statues regarding to the results, proposed that pomegranate seed or other derivatives, raw or processed form could have a potential effect on economical and health parameters of domestic animals. also regarding to lowering ph potential of pomegranate seed, it's supplementation in preparturient dairy animals might be a good strategy for acidifying diet and animal body to the prevention of metabolic disorders.