The Effectiveness of Biotin (Vitamin B7) Added to the Diet in Improving the Efficiency of Productivity, and Some Physiological Traits for Broiler Chickens (Ross-308) Exposed to Oxidative Stress.

Biotin (B7) acts as an antioxidant, as it inhibits the effect of many free radicals that are naturally formed within the organism's body. This study aimed to determine the effect of adding different concentrations of biotin to the diet of broilers exposed to oxidative stress in improving productive and physiological performance. 180 unsexed Ross-308 one-day age chicks of broiler chickens were used, and they were reared together until 7 days. Then the chicks were randomly distributed into 5 treatments; each treatment included 3 replicates, 12 chicks for each replicate. Oxidative stress was induced by adding 0.5% H2O2 to drinking water. The first treatment, T1 (control), was free from adding B7 or H2O2, and the second treatment (T2): was a positive control treatment free from adding vitamin B7 + water added to it H2O2 at an average of 0.5%. The third treatment (T3): adding 550 micrograms of B7/kg of feed + water added H2O2 at an average of 0.5%. Fourth treatment (T4): 650 micrograms/kg vitamin B7 + water with 0.5% H2O2 added on average. Fifth treatment (T5): 750 micrograms of vitamin B7/kg of feed + 0.5% H2O2 added to the water. The results of adding vitamin B7 to the diet of T4 and T5 birds exposed to oxidative stress showed a significant increase (P<0.05) in the average live body weight, total weight gain and cumulative feed consumption average, and the best cumulative feed conversion ratio for treated birds (T3, T4, T5). In comparison to the other therapies, all additional vitamin B7 treatments demonstrated a significant decrease (P<0.05) in the concentrations of glucose, cholesterol, triglycerides, as well as Malondialdehyde (MDA), and low-density lipoproteins (LDL) and a significant increase (P<0.05) in the concentrations of high-density lipoproteins (HDL) and total protein. The concentration of glutathione peroxidase (GSH-Px) was significantly elevated (P<0.05) in the serum of T5-treated birds compared to all other treatments. We conclude that adding vitamin B7 in different concentrations improved the productivity and some physiological traits of broilers exposed to the induced oxidative stress compared with the negative and positive control treatments.

Prediction of the benefits from dose-escalated hypofractionated intensity-modulated radiotherapy for prostate cancer.

PURPOSE: To estimate the benefits of dose escalation in hypofractionated intensity-modulated radiotherapy (IMRT) for prostate cancer, using radiobiologic modeling and incorporating positional uncertainties of organs. MATERIALS AND METHODS: Biologically based mathematical models for describing the relationships between tumor control probability (TCP) and normal-tissue complication probability (NTCP) vs. dose were used to describe some of the results available in the literature. The values of the model parameters were then used together with the value of 1.5 Gy for the prostate cancer alpha/beta ratio to predict the responses in a hypofractionated 3 Gy/fraction IMRT trial at the Christie Hospital, taking into account patient movement characteristics between dose fractions. RESULTS: Compared with the current three-dimensional conformal radiotherapy technique (total dose of 50 Gy to the planning target volume in 16 fractions), the use of IMRT to escalate the dose to the prostate was predicted to increase the TCP by 5%, 16%, and 22% for the three dose levels, respectively, of 54, 57, and 60 Gy delivered using 3 Gy per fraction while keeping the late rectal complications (>/=Grade 2 RTOG scale) at about the same level of 5%. Further increases in TCP could be achieved by reducing the uncertainty in daily target position, especially for the last stage of the trial, where up to 6% further increase in TCP should be gained. CONCLUSIONS: Dose escalation to the prostate using IMRT to deliver daily doses of 3 Gy was predicted to significantly increase tumor control without increasing late rectal complications, and currently this prediction is being tested in a clinical trial.