Exposure of rabbit bucks to summer heat stress reduces their homeostasis and semen quality leading to a temporal subfertility. The potentiality of ethanolic extract of Moringa oleifera leaves (M. oleifera ethanolic extract (MLEE)) to reduce negative impacts of heat stress on physiological and semen quality traits was investigated. A total of 28 adult V-line rabbit bucks were randomly distributed among four experimental groups of seven rabbits each. The first group received water (placebo) and served as a control (M0). The other three groups were given orally MLEE at levels of 50 (M50), 100 (M100) and 150 (M150) mg/kg BW every other day for 12 consecutive weeks during the summer season. Chemical constituents of MLEE were detected by gas chromatography/MS. During the experimental period, ambient temperature and relative humidity were recorded daily and were used to estimate temperature and humidity index. Feed intake, BW, rectal temperature were recorded and blood serum biochemical attributes were determined. Semen samples were collected weekly and were analyzed for semen quality traits. Results showed that MLEE contained high percentages of long-chain fatty acids and antioxidant agents. Feed intake and BW were not affected significantly by the treatment, however rectal temperature was decreased significantly by 0.42°C, 0.24°C and 0.40°C in the M50, M100 and M150 groups, respectively, compared with the M0 group. Treatment with 50 mg/kg BW increased concentration of serum albumin (115%; P<0.05), total antioxidant capacity (132%; P<0.05) and testosterone (160%; P=0.098) as well as seminal plasma initial fructose (127%; P=0.092) compared with the control group. Compared with the control, MLEE supplementation with 50, 100 and 150 mg/kg BW increased significantly sperm concentration by 118%, 151% and 158%, sperm progressive motility by 117%, 120% and 118%, sperm viability by 129%, 137% and 127%, sperm normal morphology by 114%, 113% and 114%, intact acrosome sperm by 109% (on average) and sperm with integrated cell membrane by 109%, 123% and 114%, respectively. In conclusion, MLEE supplementation at a level of 50 mg/kg BW could be effectively used to improve heat tolerance, oxidative status and semen quality of rabbit bucks during summer season.

Heat stress can impair the general health of rabbit bucks by disturbing physiological homeostasis with negative consequences in animal welfare and remarkable decline in reproductive performance. Selenium (Se) can control a number of vital biological processes. Thus, the effects of organic selenium (OSe) supplementation on the blood metabolites, redox status, semen quality, testicular histology, seminal plasma protein profile, and fertility of rabbit bucks kept under natural heat stress conditions were studied. Adult V-line male rabbits were fed a basal diet supplemented with 0.3 mg OSe/kg dry matter (DM) diet (OSe, n = 9) or not (control, CON, n = 9) for 12 weeks. The results showed that rabbits fed the OSe diet had 73.68 and 68.75% higher (P < 0.05) OSe concentrations in the blood serum and seminal plasma, respectively, than rabbits fed the CON diet. The OSe diet significantly decreased the rectal temperature and respiration rate and significantly increased the blood serum concentrations of total protein, albumin, glucose, and glutathione peroxidase compared to the CON diet. Rabbits fed the OSe diet had lower reaction times (12.53 vs. 5.84 s, ± 0.79, P < 0.01) and higher total functional sperm counts (116.74 vs. 335.23 × 10 6 /ml, ± 24.68, P < 0.001) and percentages of integrated sperm membranes (60.38 vs. 79.19%, ± 1.69, P < 0.01) than rabbits fed the CON diet. Rabbits fed the OSe diet had higher (P < 0.01) contents of seminal plasma total protein, albumin, alanine transaminase, fructose, and total antioxidant capacity and lower (P < 0.001) malondialdehyde (MDA) levels than those fed the CON diet. Rabbits fed the OSe diet had sperm cells with higher levels of integrated DNA than those fed the CON diet. The seminal plasma of rabbits fed the OSe diet contained four new proteins, with molecular weights of 19.0, 21.5, 30.0, and 44.0 kDa. The kindling rates, litter size, and weight at birth of females mated with males fed the OSe diet were significantly higher than those of females mated with males fed the CON diet. In summary, the inclusion of 0.3 mg OSe/kg DM diet of naturally heat-stressed rabbit bucks countered the negative impacts of elevated environmental temperature on physiological homeostasis, semen quality, and fertility.

No abstract

The present study was undertaken to determine the effect of chronic treatment with two sublethal doses of Dimethoate (organo-phosphorus) or Deltamethrin (pyrethroid) on body weight and semen characteristics in adult male rabbits. Pesticide treatment resulted in a decline in body weight, libido, ejaculate volume, sperm concentration and semen initial fructose; and an increase in abnormal and dead sperm and methylene blue reduction time. In this regard Dimethoate showed greater effects than Deltamethrin. The hazardous effect of these pesticides on semen quality continued during the post-treatment period, and was dose-dependent. This deleterious effect on sperm formation together with the decline in libido suggest a decrease in testosterone secretion by pesticide treatment.

Water requirements and metabolism were studied in eight each of Barki and Rahmani sheep and eight Baladi goats. The animals were individually housed in the shade in semi-open pens that were located in a non-desert area. The experiments were carried out during spring, summer and winter seasons, and each experiment lasted for 3 weeks during each season. After a preliminary period of 1 week, an 8-day period was then followed during which body weight, daily feed intake and daily drinking water were recorded. Rectal temperature and respiration rate were also recorded in the early morning and late afternoon. Four animals from each group were then weighed and injected intravenously with tritiated water, TOH (001 mCi/kg body weight) and blood samples were collected during a 4-day period to estimate total body water (TBW) and water turnover rate (WTR).In all seasons studied, the Rahmani sheep had higher TOH disappearance rate (^-values) and WTR and consequently shorter biological half-time (t0 than the Barki. Moreover, the Barki sheep showed less thermal discomfort than the Rahmani particularly during the summer. Although the Rahmani sheep ingested more water than the Barki sheep during the summer, the Rahmani sheep had a lower percentage of TBW and their calculated water loss revealed that they were in negative water balance during this season. Accordingly, the Barki sheep seem to perform better than the Rahmani in newlyreclaimed desert areas. Baladi goats appear to be more adapted to unfavourable environmental conditions than sheep. This is based upon the findings that they had lower ^-values, lower WTR, longer ti and higher TBW, than the two breeds of sheep.TNTRODnrTTON w e " a s * ne phy s '°'°g' ca ' responses (rectal temperature and respiration rate) of Barki and Rahmani Determination of daily water exchange between sheep and of Baladi goats during spring, summer animals and their environment is important for the and winter seasons, estimation of their water requirements and the evaluation of their adaptability and productivity. In MATERIALS AND METHODS ruminants daily water turnover rate is influenced by breed, environmental temperature, pregnancy, lacta-The present study was carried out on 16 ewes tion, age, sex and availability of water in the (including eight desert-adapted Barki and eight environment (MacFarlane & Howard, 1972; Mackie, temperate-evolved Rahmani) and eight Baladi 1977;Degen & Young, 1981;Khan, 1983). Intro-goats belonging to the University of Alexandria duction of sheep and goats to the newly-reclaimed Experimental Station. The experiments were indesert areas of Egypt necessitates the determination itiated in April 1983 and were terminated in February of their daily water turnover rate, in order to ensure 1984. All animals were dry, non-pregnant and were adequate water supply and to choose the species or 1-2 years of age at the beginning of the experiment, the breed which is better adapted to arid and semi-The animals ^were individually housed in semi-open arid conditions. Such animals should b...