ABSTRACT
Published data on the effects of essential oils [EO] on in vivo nutrient digestibility in sheep are contradictory. In 2 experiments, the effect of thymol and carvacrol on nutrient digestibility was studied in sheep fed with high [70%] or low [52%] concentrate diets, using incomplete Latin Square designs. The essential oils were mixed with the concentrate portion of the diet at the rate of 0.0, 0.3, or 0.6 g per kg dry matter [DM] diet. Supplementation of thymol had no significant effect on digestibility of dry matter [DM], organic matter [OM], crude protein [CP] and acid detergent fiber [ADF]. The main effect of thymol on neutral detergent fiber [NDF] and ether extract [EE] digestibility and on nitrogen balance [NB] was significant [P<0.05], but within each level of dietary concentrate no significant differences were observed for these measurements. Overall, ruminal ammonia concentration was higher [P<0.05] in both HCD and LCD lambs receiving 0.3 mg thymol per kg diet. Supplementation of carvacrol had no significant effect on nutrient digestibility. The main effect of carvacrol on ruminal ammonia levels and NB was significant, but within each level of dietary concentrate no significant differences were observed in ammonia levels and NB. Inclusion of 0.3 g/kg diet DM of carvacrol or thyme was more effective than 0.6 g/kg diet DM in terms of NB but neither dose affected nutrient digestibility. Future research should determine the long-term effects of essential oils on digestibility and performance in sheep, before recommendation can be made for their use under practical husbandry conditions
ABSTRACT
This study was carried out to investigate the relationship between early lactation curve parameters and calving interval in Holstein cows of Iran. In order to describe the lactation curve, the incomplete gamma function was fitted to 5,754,428 test-day milk records corresponding to 766,108 lactations on 315,634 cows in 2,448 herds. Cows with higher milk yield during early lactation had shorter calving intervals; however, longer calving intervals increased the 305-d milk production [P<0.01]. Cows with higher yield at the beginning of lactation, steeper ascending, and steeper descending slope had shorter calving intervals [P<0.01]. Calving interval was increased by 2.73 [+/- 0.12] d for every extra kg of milk at peak lactation [P<0.01]. The calving interval was directly impacted by the persistency of milk yield, but milk yield persistency was reduced in cows with shorter calving intervals [P<0.01]
ABSTRACT
No domestic availability to breeder turkey stocks and turkey hatching eggs prompted the present experiment that aimed to evaluate the feasibility of a conventional artificial insemination [AI] procedure in British United Turkey [BUT] for the first time in Iran. Broiler turkeys were restrictedly fed, grown for 46 weeks, and used for the current study [10 turkey toms and 24 turkey hens in total]. After a 3 week period of habituating the toms to abdominal massage, the pooled semen was used for insemination after the dilution in sterilized and homogenized low-fat milk [at the ratio of 1 to 6]. The hens were inseminated [14:00 h] and hatching eggs were collected [n = 148]. All the eggs were broken open to assess the fertility rate. Although being lower than the conventional average fertility rate noticed for breeder turkeys in the production manuals [91%], a fertility rate of 61.5% was obtained. The present report provided a preliminary data on the feasibility of the conventional procedure used in chickens to artificially inseminate the turkey, using low-fat milk as a simple available extender. The present findings might also be promising to the future establishment of turkey breeder enterprise in Iran
ABSTRACT
The Increase of oxidative stress production a causes after oxygen free radicals one of the factors involved in male infertility. In this study the role of leptin in product reactive oxygen species in seminal plasma in adult rat were evaluated Sixty-five male rats were randomly divided into four groups. The control group receives normal saline and other animal, in experimental groups 2, 3 and 4 were given daily intraperitoneal leptin injections of 5, 10, or 30 mg/kg body weight for 7, 15 and 42 at all. Reactive Oxygen Species Levels and Expression of leptin were measured respectively with DCFH-A and immunohistochemical and sperm parameters were assessed by computer-assisted semen analysis [CASA]. Two ways ANOVA with Tukey post hoc test were conducted to compare mean of groups. P-value < 0.05 was considered significant. The results show that sperm count was higher in treated groups than that of control group. These differences were significant [p
ABSTRACT
Effect of propylthiouracil [PTU]-induced hypothyroidism during the prepubertal period, at a dose of one g per kg of the diet, on serum testosterone level and seminal characteristics of Pars indigenous chickens was studied. PTU was fed between 7th to 13th weeks of age and semen was collected at weekly intervals, starting at 21st week of age and continued for seven weeks. The effect of PTU treatment on serum testosterone level and body weight was significant [P<0.05], The effect of age on all parameters, including body weight, semen volume, sperm motility, percentage of live sperm, sperm concentration, total number of live sperm, and serum testosterone and thyroxine T[4] levels was also significant [P<0.01]. The interaction effect of PTU treatment and age on semen volume, sperm motility, and percentage of live sperm was not significant [P>0.05]; but it was significant for body weight, sperm concentration, total number of live sperm, and serum testosterone and T[4] levels [P<0.01]. At weeks 11 and 13 of age, serum T[4] concentration in PTU birds was significantly lower but serum testosterone level was higher than in the control group. Sperm concentration in PTU birds was generally higher than in the control group, although the differences between the two groups were significant at weeks 20, 23 and 24. The total number of live sperm produced by PTU birds at week 21 of age was about 60% of the control group [P<0.01]. A positive correlation [P<0.01] was found between testosterone level and body weight [r = 0.54 and 0.36 for the control and PTU groups, respectively]. A small but significant positive correlation was found between T[4] levels and body weight in the PTU group [r = 0.23; P<0.01], but not in the control group [P>0.05]. The correlation between testosterone and T[4] levels was not significant. Transient prepubertal PTU-induced hypothyroidism resulted in an increase in sperm concentration and production at certain stages after treatment, but the effect did not seem to last for a long period. The potential for increased efficiency associated with raising smaller birds which pass a neonatal hypothyroidism and eat less feed and produce normal semen, may be economical