Thermal stress causes oxidative stress and physiological changes in female rabbits.

The present study investigated the effects of heat stress on oxidative stress status and physiological changes using female New Zealand White rabbits. 24 sexually mature female rabbits weighing 1953.1-2375.4 g were divided into 4 groups of 6 animals each and subjected to ambient temperature (T0: 19-26 °C), 27-28 °C for T1, 31-32 °C for T2 and 35-36 °C for T3 using electrical heaters from 8:00 a.m. to 4:00 p.m. daily for 30 days. Feed intake and body weight gain were recorded daily. Behavioral alterations of anxiety, dizziness, aggression, withdrawal, impaired feed intake were observed. At the end of experimental period animals were sacrificed, blood samples and vital organs such as liver, kidney, heart, ovaries, uterus collected for appropriate analysis. Results revealed that animals of T2 and T3 had an 11% decrease in the final body weights and 62% body weight gain but increase in feed conversion ratio by 64.81%, 24.19% water intake, 3.64% in rectal and 2.42% in skin temperature compared to the control. Dizziness, withdrawal to a corner of the cage and reduced feed intake were observed. The live weight of lungs and kidneys increased by 37.71% and 33.78% while that of ovaries and uterus decreased in the same animals of T2 and T3. Animals from T2 and T3 showed significant decrease (p < 0.05) by 23.64% in hemoglobin concentration, 12.73% in red blood cells, 11.93% in packed cell volume, 12.02% in total protein while mean corpuscular volume, white blood cells, lymphocytes, creatinine, urea and aspartate transaminase increased respectively by 10.73%, 42.37%, 15.53%, 28.98%, 53.2% and 23.31% compared to the control. The kidney level of malondialdehyde was significantly increased in T2 and T3 animals by 74.29%, whereas protein, catalase, superoxide dismutase and glutathione peroxidase activity were significantly lower (p < 0.05) compared with control. It was concluded that long-term exposure of female rabbits to elevated ambient temperatures induces heat stress and accompanying oxidative stress that consequently impairs physiological function.

Effect of dietary inclusion of small quantities of Mucuna pruriens seed meal on sexual behavior, semen characteristics, and biochemical parameters in rabbit bucks (Oryctolagus cuniculus).

The aim of this work was to investigate the effects of Mucuna pruriens seed meal (MSM) on sexual behavior, semen, and biochemical parameters in rabbit bucks. Twenty-four 12-week-old rabbit bucks weighing 1002 to 1156 g were randomly allocated to three experimental diets containing 0, 1.5, and 3% of MSM in a 3-month trial. Sexual behavior parameters such as mounting latency, mounting frequency, successful mounting frequency, intromission latency, and post ejaculatory interval were monitored at the end of the experiment by mating with receptive females. Thereafter, rabbits were weighed, stunned, and humanely sacrificed and testes, epididymis, and vas deferens were harvested for evaluation of organ weights and semen characteristics. Results indicate that supplementing rabbit diet with MSM induced a significant decrease (P < 0.05) in mounting latency (69.7%) and intromission latency (19.7%), while it significantly (P < 0.05) increased successful mounting frequency (60%) as well as relative weight of testis (33.3%) and vas deferens (54.5%). There was a dose-dependent increase (P < 0.05) in sperm motility (35.7%) and concentration (65.9%), serum albumin (19.1%) and protein concentration (9.9%), and a decrease in sperm morphological alterations (68.3%), serum cholesterol (13.4%), and urea (11.6%) in treatment groups where MSM was supplemented at 3% compared to controls. From the findings, it appears MSM is a potential enhancer of male reproductive performance that can be recommended to rabbit farmers for improving reproductive performance and quality of semen, hence a boon to reproduction and production in rabbit farming industry.

Khat (Catha edulis) lowers plasma luteinizing hormone (LH) and testosterone secretion, but increases cortisol levels in male rabbits.

AIM: This study investigated the effects of fresh khat extract on specific circulating hormones in male rabbits. MATERIALS AND METHODS: A total of 25 male New Zealand White rabbits were divided into five groups each comprising five animals. The first four groups were fed four doses (1.5 g/kg, 4.5 g/kg, 13.5 g/kg and 40.5 g/kg body weight) of khat extract twice a week for 5 weeks while the last group, serving as control, was fed only normal saline via intragastric tube. Blood samples were collected at 15 min interval for up to 3 h after khat extract administration and plasma assayed for luteinizing hormone (LH), testosterone and cortisol levels using radioimmunoassay technique. RESULTS: Khat extract at all doses significantly lowered (P<0.05) LH pulse frequency, area under LH curve, mean plasma LH and mean plasma testosterone levels. Plasma cortisol levels were significantly elevated (P<0.05) in khat-treated rabbits in a dose-dependent manner. CONCLUSION: This study demonstrates that khat may impair reproductive function in male rabbits by interfering with sex hormone profiles.