فهرست مطالب امیر کرم زاده دهاقانی

Selenium, a vital element in the body, plays a crucial role in the functioning of enzymes related to antioxidant defense, fertility, and the immune system. This study seeks to explore how various selenium sources impact the semen quality of aging broilers under lipopolysaccharide stress (LPS). A 2×3 factorial experiment involved 96 Ross 308 strain roosters at 45 weeks of age, organized into four replications of three birds each. The experiment included three selenium sources: mineral selenium (sodium selenite), organic selenium, and nano-bio chelate of selenium, added to the diet. Semen was assessed before LPS injection and after the final LPS injection at the experiment's conclusion. Evaluation indicators comprised malondialdehyde (MDA) concentration in semen, total oxidative capacity, glutathione peroxidase activity in semen, and testosterone levels in blood plasma. Statistical analysis utilized SAS 9.4 through GLM or MIXED procedures.The total antioxidant capacity and glutathione peroxidase activity levels exhibited variations among the groups. Specifically, in the LPS-receiving group, the control group demonstrated significantly lower total antioxidant capacity compared to the Selmax and Bendacel groups that received PBS. Additionally, the control group exhibited lower glutathione peroxidase activity compared to the Selmax group that received PBS, although no differences were observed between this group and others. Moreover, the Selmax group that received PBS displayed the lowest amount of MDA, a significant difference from the control and sodium selenite groups that received LPS. Notably, the testosterone concentration in birds that received Bendacel and sodium selenite, and were challenged with PBS, was significantly higher than in birds that received LPS without any source of selenium. The study demonstrated that using organic selenium from Selmax and Bendacel sources has the potential to enhance the reproductive performance of aged roosters, mitigating the adverse effects of aging. Notably, the effective addition of 0.30 mg/kg of organic selenium emerged as a positive intervention in improving reproductive outcomes in the study's context.

In order to improve fertility, selenium supplementation serves as an important consideration in animals' diets. The impacts of selenium supplementation depend on the source and quantity of selenium in the diet, so this study was performed to evaluate the effects of different selenium sources on sperm quality parameters in aged broiler breeder roosters (BBR). The study took place over a 40-day period; for the first two weeks, all birds received the same basal diet, and then for the next 40 days, the roosters were fed the experimental diets containing different sources (i.e., sodium selenite, organic selenium, and selenium nano-bio-chelate) and levels of selenium (i.e., 0, 0.15, 0.30, and 0.45 mg/kg). Every ten days, sperm was collected from the BBR by the belly rub method. The collected sperm was evaluated for several qualitative parameters such as volume, concentration, viability, and plasma membrane function. Each parameter was assessed using the General Linear Model (GLM) procedure of SAS 9.4 software. The results of the present study showed that supplementing the diet with selenium at a level of 0.30 mg/kg, regardless of its source, led to an increase in the concentration and motility percentage of sperm, as well as a decrease in the percentage of abnormal sperm. Furthermore, the plasma membrane function of sperm was also enhanced following the addition of selenium to the diet. These findings suggest that selenium supplementation, particularly at a level of 0.30 mg/kg, may improve sperm quality parameters and promote fertility in aged BBR. The present study indicated that the dietary supplementation of selenium, particularly at a level of 0.30 mg/kg, has a positive impact on the reproductive performance of old roosters. The results revealed that the organic form of selenium, such as Selmax and selenium nano-bio-chelate were more effective than sodium selenite, a popular inorganic form of selenium, in enhancing the fertility of the roosters.

To investigate the effect of oral administration of prepared specific egg yolk antibody (IgY) against enterotoxigenic Escherichia coli K99 on growth performance, health, the prevalence of diarrhea of neonatal calves, an experiment was conducted using 60 newborn calves in a completely randomized design with two treatments. Calves were kept individually. Calves in the control group received only milk or colostrum for 30 days and calves in the treatment group received milk or colostrum with IgY against inactivated K99. During the experiment, health parameters and the prevalence of diarrhea were recorded daily, and growth performance was evaluated weekly. The results showed that average daily gain, starter dry matter intake and feed and milk efficiency were higher in the IgY group than the control group (P<0.05). The general health score in the IgY group was higher than control group and fecal and ear scores in this group were significantly lower than the control group (P<0.05). The count of fecal coliforms in the IgY group was decreased by approximately one log compared to the control group (P<0.05). The results of the present study showed that oral administration of IgY against enterotoxigenic Escherichia coli K99 has beneficial effects on health and average daily gain of suckling Holstein calves and It can be a good way to replace antibiotics.

Introduction Dry period is an important factor for milk yield, udder health and also cow's reproduction. Persistency of milk production in high producing dairy cows, increased income from milk production per cow in 305 days. In the other side, in recent decades, much attention to increasing milk production in dairy cows and genetic selection of high producing animals, has been caused many problems such as negative energy balance and reproductive disorders. Shortening or removing the dry period, may to improve health status and reproductive performance of cows. The relationship between energy balance and reproduction is well proven. Body condition score (BCS) at mating, and duration and severity of negative energy balance after calving affect pregnancy rate. The purpose of this study was to evaluate the effect of shortening the dry period and the number of parturition and interaction between them, on health and reproduction and productive performance in Holstein dairy cow.
Materials and Methods 80 Holstein cows were used in a 2 × 2 factorial design from 56 days before to 56 days after calving. Cows (n=20) were randomly assigned to two groups on the basis of dry period length (56 or 28 days) and number of calving (two or three times of calving rate). The animals were fed three times a day. Dairy cattle rations based on the requirements was adjusted in the period before and after calving. Cows were milked three times a day and the amount of milk yield was recorded for six weeks. To determine the composition of milk, a mixture of daily milk was used and evaluated weekly. BCS, based on the system of five numbers was determined. Reproductive records including open days, pregnancy rate in four inseminations and days to first service was determined. The indicators of the uterine health of the cow containing metritis and endometritis incidence was assessed. Blood samples of cattle, on the day of entry into the study (56 days before the expectable calving), 28 and 7 days before calving and day 7, 28 and 56 after calving were measured. The concentrations of glucose, urea, triglycerides, total cholesterol, LDL-cholesterol, beta-hydroxy butyric acid (BHBA) and non-esterified fatty acids (NEFA) in the blood were measured. Data were analyzed by SAS software.
Results Milk yield was tended to be lower in group 28 than that in group 56 (P= 0.06). But milk composition and somatic cells of cows with 28 days dry period, does not have a significant difference with control group (56 days dry period). Means BCS after calving in the 28 days group, was lower than those of 56 day group (P