مجله علوم دامی ایران
سال پنجاه و دوم شماره 3 (پاییز 1400)

This experiment was conducted to evaluate effect of feed form and stocking density on performance and some behavioral parameters of 208 one-day-old broiler chickens (Ross 308), for 42 days.  Treatments were 2 feed forms (pellet versus mash) and 2 levels of density (10 and 16 birds/m2) that was performed in completely randomized design with 2×2 factorial arrangement and 4 replicates. Performance parameters were recorded weekly and carcass characteristics measured on day 42 of age. For evaluating behavioral parameters, 8 cameras were used. The results showed that feed intake, body weight gain and feed conversion ratio were improved in broilers fed pellet diets compared to the birds fed mash diets at whole period of experiment (P<0.05). Abdominal fat was increased in birds that consumed mash diet in high stocking density (P<0.05). In the morning of the third week, the activity index of birds that consumed mash diet in high stocking density increased significantly (P<0.05). The results of this study indicate that feed form could not affect performance and behavioral parameters of broilers in high stocking density, although, pelleting diets improved performance parameters and high stock density increased average around feeder activity of broiler chickens.

The objective of this study was to compare solvent soybean meal with extruded soybean meal at 135°C on performance and metabolic status of fresh Holstein cows. Twenty-four Holstein cows (BW± SD; 614.45± 28.33) were randomly assigned to 1 of 2 experimental treatments from caving until 21 days in milk: 1- control (containing solvent soybean meal; SSBM) and 2- experimental (containing extruded soybean meal; ESBM). Cows were housed in individual stalls, fed with total mixed ration, and feed offered and ort were recorded daily. Milk yield was recorded daily and milk sampls were taken weekly to determine its composition. Body weight and body condition score of cows were determined at immediately after calving and 21 DIM. Dry matter intake in ESBM cows was greater than SSBM cows (P˂ 0.01). Cows fed ESBM produced 3.71 kg/d more milk than SSBM cows (P< 0.05). Milk fat content in ESBM cows was lower than SSBM cows (P<0.05). The ESBM cows had lower serum glucose concentration (P<0.01) and higher cholesterol (P<0.01) than SSBM cows. Rectal temperature, BCS and BW changes, and feed efficiency were not different between treatments (P>0.1). Overall, the results of this study showed that replacing solvent soybean meal with extruded soybean meal increased DMI and milk yield of fresh cows.

With the aim of investigation, the effects of oak acorn (OA) (0 or 20 % of diet) and tannin-reducing feed additives (without additive, 10 g polyethylene glycol (PEG)/kg of diet and 0.25 % diet sodium bicarbonate) on performance and liver and kidney tissues of broiler chickens, a total of 480 Ross 308 broiler chicks (average body weight of 41 gram and same male to female ratio) were distributed among 6 experimental treatments (4 replicates of 20 birds) in a 2×3 factorial arrangement and reared for 42 days. The results indicated that application of OA had no significant effect of overall feed conversion ratio, but significantly decreased overall body weight gain. However, sodium bicarbonate improved overall body weight gain, compared to the diet without additive. Feeding birds with OA significantly increased relative weight of gizzard, ileum and caecum at 24 d of age and relative weight of caecum and duodenum at 42 d of age. On d 24, more sever cellular congestion was observed in liver tissue of OA fed birds, but on d 42, the number of liver fat vacuole was less in these birds. Feeding with OA increased diameter of renal corpuscle. In conclusion, dietary inclusion of 20% OA had no significant effects on feed conversion ratio and liver as well as kidney tissue of broilers, but because of significant reduction in overall body weight gain and production efficiency factor, this level is not recommended. However, inclusion of additives did not prevent this reduction.

Using 36 Hubbard grandparent roosters at 45 weeks of age, the present study investigated the effects of supplementing vitamin E and soybean lecithin in the roosters' diet on their semen quality. The experiment was conducted in a completely randomized design with four treatments including basal diet, basal diet supplemented with vitamin E (300 mg/kg), basal diet supplemented with lecithin (1%), and basal diet supplemented with lecithin & vitamin E. Roosters were fed their diets for 60 days and semen collection was performed on days 0, 20, 40 and 60 of the experiment. The results showed that the treatment containing vitamin E + lecithin significantly improved total sperm motility and sperm concentration (P<0.05). The semen volume and sperm kinematic values were not affected by experimental diets (P>0.05). Although experimental treatments had no effect on abnormal morphology of sperm and DNA fragmentation, but membrane integrity and sperm viability were significantly increased in roosters fed diet supplemented with soybean lecithin and vitamin E (P<0.05). Malondialdehyde (MDA) concentration was also shown to be significantly lower in treatment containing vitamin E and soybean lecithin (P<0.05). The interaction effects of time× diet on total and progressive motility, sperm concentration, viability, membrane integrity and MDA content were significant (P<0.05) and these traits improved in the last days of the experiment due to diet supplemented with vitamin E+ soybean lecithin. Overall, it was concluded that supplementing aged roosters' diet with vitamin E and lecithin appears to improve sperm quality traits.

To compare the effects of injection different levels of selenium and vitamin E in late pregnancy on thyroid hormone metabolism and biochemical parameters of Holstein cows and their calf performance, 28 pregnant Holstein cows were selected in 8 weeks before calving and randomly assigned to 4 treatments and 7 replications. Cows were then injected with selenium and vitamin E four and two weeks before the expected time for calving. Treatments included: injection of 0 (contro), 15, 30 and 45 ml of selenium and vitamin E supplements. Each ml of supplement contained 0.5 mg of selenium in the form of sodium selenite salt and 50 international units of vitamin E in the form of DL alpha tocopherol acetate. Cows were balanced in terms of age, weight and calving time. The results showed that injection of selenium and vitamin E in pregnant cows affected the weight performance of their calves (P<0.05) so that the daily weight gain and weight of calves at 30 and 45 days of age in Selenium and vitamin E treatments increased, compared to the control group (P<0.05). Receiving of selenium and vitamin E makes pregnant cows resistant to low blood glucose and triglycerides in the postpartum period. At one week after delivery. The concentration of glucose and blood triglycerides in the injected cows increased compare to the control treatment (P<0.05). Also, one week before and after delivery, with increasing the dose of selenium and vitamin E, the activity of glutathione peroxidase and the concentration of tetrahydrotyronine and triiodothyronine increased (P<0.05). In general, according to the present results, at least 30 ml of selenium and vitamin E at the end period of pregnancy for Holstein cows, could be recommended.

The present study was conducted to investigate the effect of different levels of alkaline treated feather meal and dried corn steep liquor on the performance of broiler chickens. A total of 720 one-day-old broiler chicks were randomly distributed into six experimental groups in a simple randomized experimental design (each experimental group had six replicates; 20 birds per each). Experimental groups contained: 1: Feed without dried corn steep liquor (DCSL) and alkaline treated feather meal (ATFM), 2: 4% DCSL and 3.29% ATFM, 3: 5.5% DCSL and 2.47% ATFM, 4: 7% DCSL and 1.65% ATFM, 5: 8.5% DCSL and 0.82% ATFM, 6: 10% DCSL. The results showed that experimental treatments could not affect feed intake, weight gain and feed conversion ratio (P> 0.05). The average production cost per kilogram of live weight at 11-24 days did not show a significant difference (P>0.05). The highest average production cost per kilogram of live weight in the grower period (25-42 days) and the whole experimental period (11-42 days) was related to the control group (P<0.05). The use of different levels of alkaline treated feather meal and dried corn steep liquor had a significant effect on the percentage of crude fat and lipid oxidation of meat (P<0.05). According to the results, it can be concluded that partially substitution of soybean meal with alkaline treated feather meal and dried corn steep liquor can be done without any negative effects on performance and it reduces production costs.