Evaluation of Total Antioxidant Activity and Oxidative Stress in Seminal Plasma from Dogs Supplemented with Fish Oil and Vitamin E.

BACKGROUND: We evaluated the effect of fish oil (FO) and FO in addition to vitamin E (VE) supplementation on total antioxidant activity of dog seminal plasma, and further assessed oxidative stress. Additionally, we measured the effect of this supplementation on hematological parameters and serum biochemistry. MATERIALS AND METHODS: In this experimental study, six male dogs were assigned to one of the following three groups for a period of 60 days using a replicated 3×3 Latin square design: control (CG), FO (FOG) and FO in addition to VE (FOEG). On days 0 and 60 of the trial, semen and blood samples were obtained. 2,2V-azino-bis (3-ethylbenzothiazoline- 6-sulfonate) (ABTS) and ferric reducing antioxidant power (FRAP) assays were used to determine total antioxidant activity. Oxidative stress was determined by measuring total sulfhydryl group (T-SH). RESULTS: Dogs supplemented with FO alone had a lower total antioxidant activity in seminal plasma (ABTS: -59.86% vs. CG and -57.3% vs. FOEG; and FRAP: -37.3% vs. CG and -40.5% vs. FOEG), and higher oxidative stress (T-SH: +53.0% vs. CG and+60.2% vs. FOEG) compared with the other two groups (P<0.05). Serum triglyceride (TG) concentration decreased in FOG and FOEG compared with CG, on day 60 (P<0.01). CONCLUSION: We concluded that total antioxidant activitydecreased and oxidative stress increased in seminal plasma of dogs after FO supplementation for 60 days.

Physical response of dogs supplemented with fish oil during a treadmill training programme.

The rise in popularity of dog sports competitions has led to the evaluation of improvements in dog physical performance. The potential benefit of dietary supplementation with fish oil (FO) on the physical performance of human beings and horses has been reported. However, such effect has not been studied in dogs. We therefore evaluated the effect of FO dietary supplementation on heart rate (HR), rectal temperature (RT) and thigh circumference (TC) in dogs during aerobic treadmill training, and further determined HR response and blood lactate (BL) concentration during an incremental exercise test. Using a cross-over design, eight male dogs were randomly assigned to two groups and received a standard balanced commercial diet (control, CG, n = 7) and the same diet supplemented with 54 mg FO/kg metabolic weight per day (FOG, n = 8). All dogs had 30-min treadmill sessions at 8 km/hr and 7.5% slope twice a week for 12 weeks. Assessment of HR and RT was performed before and immediately after each session; HR was also assessed 5 min after the end of each session. Thigh circumference was evaluated before each session. All dogs performed an incremental exercise test on the treadmill at 0, 6 and 12 weeks to evaluate HR response and BL concentration. Data were analysed using the mixed procedure (SAS 9.4). In FOG, pre-HR (-4.9%) and post-HR (-2.4%) values and post-RT (-0.3%) values were lower during treadmill training, whereas TC (+2.2%) values were higher as compared with CG (p < 0.01). Through the incremental exercise test, mean HR (week 6, -5.3%; week 12, -6.0%) values in FOG were lower than in CG (p < 0.05). In conclusion, FO supplementation slightly improved the physiological response of dogs to exercise during training.

Physiological parameter values in greyhounds before and after high-intensity exercise.

Dog sports competitions have greatly expanded. The availability of reference values for each type of activity could help assess fitness accurately. Heart rate (HR), blood lactate (BL) and rectal temperature (RT) are relevant physiological parameters to determine the dogs response to effort. Previous studies in greyhounds have reported the effect of high-intensity exercise on many physiological parameters immediately after completing different racing distances and recovery times. However, there are no studies concerning physiological changes over shorter racing distances. We therefore assessed the effect of sprint exercise on HR, BL and RT in nine greyhounds performing sprint exercise over a 100-m distance chasing a lure. After the exercise, dogs underwent a passive 10-min recovery phase. Before the exercise, immediately after it and at 5 and 10 min during recovery, HR and RT were assessed and blood samples were collected for BL determination. HR, BL and RT values increased significantly after the exercise (P<0.01). Whereas HR returned to pre-exercise values at 10 min during the recovery phase (P>0.1), BL concentration and RT remained increased (P<0.01). The abrupt increase in HR, BL and RT values observed immediately after the exercise indicates the high intensity of the effort performed. Similarly, BL concentration after the exercise exceeded the 4 mmol/L lactate threshold, suggesting a predominant anaerobic metabolism during effort. Although HR returned to pre-exercise values 10 min after the exercise, a more extensive recovery phase would be necessary for a total return to resting values, particularly for BL and RT. In greyhounds subjected to high-intensity exercise, HR, BL and RT were reliable physiological parameters to accurately assess the physiological response to effort. The use of sprint exercises over short racing distances could be useful for appropriately monitoring fitness in sporting dogs.

Effect of Long-Term Fish Oil Supplementation on Semen Quality and Serum Testosterone Concentrations in Male Dogs.

BACKGROUND: Manipulating the dietary fatty acid (FA) content can alter FA profiles of reproductive tissues. Numerous researchers have evaluated the effect of fish oil (FO) supplementation on reproductive characteristics in domestic animals, but reliable information concerning dietary FO effects on semen quality and testosterone concentrations in dogs has not been reported. Therefore, this study evaluated the effects of dietary FO on semen quality and serum testosterone concentrations in dogs. MATERIALS AND METHODS: In this cross-over experimental study, 5 male dogs consumed either a control diet or the same diet supplemented with 54 mg FO/kg metabolic body weight (BW) for 120 days. After the 120-day wash-out period, control (C) dogs received FO and FO-fed dogs consumed the control diet. In the first period, 2 dogs were allocated to the FO group and 3 to the C group. In the second period, 3 dogs were allocated to the FO group and 2 to the C group. Semen samples collected on days 0, 60, 90 and 120 were evaluated by standard methods. Day 120 semen samples were analyzed for FA profiles. Blood samples were collected on days 0, 30, 60, 90 and 120 to measure serum testosterone concentrations. Data were analyzed by analysis of variance with repeated measures using the Mixed Models procedure of SAS (version 9.0, SAS Institute Inc., Cary, NC, USA). Animals and period of time (first or second 120 days) were random variables; and treatment, time, and the treatment by time interaction were considered fixed effects. RESULTS: FO supplementation increased the percentage of motile sperm (P=0.02), total sperm count (P<0.01), total sperm viability (P<0.01), and total morphologically normal sperm (P<0.01). Supplementation decreased the percentage of viable sperm (P=0.03) and serum testosterone concentration (P<0.01). FO supplementation also increased the percentage of arachidonic acid, eicosapentaenoic acid, (EPA) and total n-3 in semen samples (P≤0.05). CONCLUSION: These results are consistent with the concept that long-term FO supplementation influences semen quality and testosterone concentrations in dogs by altering semen FA profiles.