فصلنامه پژوهشهای تولیدات دامی
پیاپی 7 (بهار و تابستان 1392)

The first experiment was designed to determine the effect of divergent selection for increase (HEW) and decrease in egg weight (LEW) in Japanese quail during three generations. These lines were established previously during two generations of divergent selection for increase and decrease in egg weight. A random bred group was also used as control group (C) that was established during three generations of random selection. After third generation selection, direct responses to selection for egg weight were 0.39 and -0.48 g in HEW and LEW lines, respectively. Also realized heritability of HEW and LEW lines were 0.30 and 0.28, respectively. There was a positive correlation between egg weight and4-wk BW in both lines (P<0.001). In the second experiment, two lines were selected for decrease (LMA) and increase (HMA) age at sexual maturity during generation 4 to 7. After four generations of individual phenotypic selection, direct responses to selection for age at sexual maturity were low. These values were –1.21 and 2.39 days for LMA and HMA lines, respectively. Realized heritability estimates of age at sexual maturity were greater in HMA (0.16) than LMA line (0.10). There was a negative correlation between age at sexual maturity and 4-wk BW in both divergent lines. BW at 4 weeks was positively correlated with BW at sexual maturity in both lines with the exception of the HMA line in the fourth generation. Age at sexual maturity and BW at the same time were positively correlated(P< 0.001) in generations 4 and 6 in the LMA and generation 6 in the HMA line.

A factorial arrangement with three levels (0, 50 and 100 mg/kg of diet) of fennel extract (FE) and three levels (0, 3500 and 4200 IU/kg of diet) of Vitamin D3 (VitD3) was carried out with 360 Ross 308 broiler breeders after molting (84 - 92 weeks). Broiler breeders were weighed at 18 weeks after molting (82 weeks of age) and then randomly distributed into 36 pens with a similar mean body weight. Each pen consisted of 10 hens and 1 rooster. The birds received experimental diets during 84-92 weeks of age. Performance data were recorded daily and egg quality traits were recorded every 4 weeks. To determine the settable hatch and fertile hatch eggs, eggs collected three times a week and incubated for 21 days. Four blood samples were taken from each pen to assay serum calcium and phosphorus concentration at the end of the experiment. Fennel extract supplementation to breeder diet significantly decreased deformed eggs and increased yolk color index and serum calcium. There were significant interactions between FE and Vit D3 levels for egg production, egg mass, feed conversion ratio, shell weight and serum calcium. The results of this experiment showed that incorporation of 50 mg/kg FE and 3500 IU/kg Vit D3 to the diet exhibit beneficial effects without any adverse effect on productive performance.

An experiment was conducted to investigate the effects of dietary conjugated linoleic acid (CLA), fish oil (n-3 rich), soybean oil (n-6 rich) or palm oil (rich in saturated and mono-unsaturated fatty acids) on performance and fatty acid profile of breast and thigh tissues in broiler chickens. The experiment was carried out as a completely randomized design with 4 treatments consisted of the experimental diets contain the different fats, 4 replicates and 20 chicks per replicate. The dietary fats were included in the experimental diets at 7% but because of the lower metabolisable energy content of palm oil, its inclusion rate was about 12.5%. The present study indicates that dietary supplementation with soybean oil or palm oil performed better than supplementation with fish oil or CLA in broiler production, but such observations occurred despite the less favored fatty acid profile of the meat produced. On the other hand, despite the acceptable effects of fish oil and CLAsupplements on enrichment of chicken’s meat, due to the poor performance, the 7% dietaryfish oil or CLA inclusion is not commercially recommended.

Four ruminally cannulated sheep were used in order to investigate the effects of alfalfa particle size (long vs fine) and canola meal treatment with hydrochloric acid solution (untreated vs treated) on feed physical characteristics, distribution of ruminal content particle size and the effect of initial chewing on decrease of particle size. Data documented from experiment analyzed at Latin square design. The method of wet sieve was used in order to determine distribution of rumen content and mild flow of water on sieves was used for dissociation of particles. Using two methods of BD100 and BD50, determination of bulk density were done. The effect of initial chewing on the amount of decrease of particle size determined by measurement of ruminal content distribution of particle size emptied at the time of measurement of saliva secretion rate. The results of this experiment showed that decrease of particle size caused increase of bulk density and insoluble ash (P = 0.0001) and in the other hand increase of particle size caused increase of water holding capacity and insoluble dry matter (P= 0.0001). Treatment with acid caused no change in physical characteristics (P> 0.05). Comparison to alfalfa, Canola meal had higher insoluble dry matter. Trend of particle size distribution for all hours showed that increase of time after feeding caused decrease of long particles percent and increase of remained particles on the end sieves (P< 0.05). Investigate the results related to escapable phase particles percent from rumen showed that Increase of time post-feeding caused increase of escapable phase particles percent from rumen and decreased of nonescapable phase particles percent from rumen (P< 0.05)

This study was carried out to determine the nutritional value and the effect of different levels of prosopis juliflora pods (fruit contain seed and pod) on laying hen performance. The amount of AME, AMEn, TME and TMEn of prosopis juliflora were 3041.81, 3041.75, 3591.51 and 3592.97 kcal/kg, respectively. Crude protein, crude fiber, ash, crude fat, calcium, phosphorus, total tannins and total extractable phenolic were 11.75, 18.8, 0.5, 1.60, 0.55, 0.09, 5.03 and 4.8 percent, respectively on dry matter basis. There were significant differences for TME and TMEn among treatments (P <0.05). In order to study the effects of mesquite pods on laying hens performance, 120 white Leghorn laying hens(at 47 weeks of age) were allocated in a completely randomized design with four treatments and six replications (five hens in each replicate) for 14 weeks (two weeks for adaption and 12 weeks for sampling). Experimental treatments were diets with 0, 5, 10 and 15 percent of mesquite pods. The results showed that there were significant differences (P< 0.05) for egg production, egg mass, feed intake, feed conversion ratio, albumen height, haugh unit, egg shell weight and specific gravity among experimental groups. In conclusion, it is suggested that Prosopis juliflora pods can be included up to 10% in diet of laying hens.

The effect of adding Carum copticum, Thymus vulgaris, Mentha piperita and Cirtus lemon essential oils (EO) to growing chick's diets at levels of 50,100 and 150 ppm on shear force value, color (CIE values L*a*b*), sensory characteristics and chemical composition (DM, CP, CF, Ash) of breast meat were investigated. A total of 312 male one-day old chicks (Local strain), were divided into 13 treatments (EO groups and control) with six replicates and 4 observations in each replicate. The results showed that the crude fat content of breast muscle derived from mint group (at low level, 50 ppm) were significantly higher compared to other ones (P<0.05). The higher EO supplementation resulted in a descending trend in the fat content of breast meat samples. Shear force value in chicks fed diets supplemented with mint EO at 150 mg/Kg diet were significantly higher than other groups (P<0.05). Our result showed that C. copticum and C. lemon EO in contrast to M. piperita improved some of the sensory characteristics of broiler breast meat (odor, taste and overall acceptability) as evaluated by trained panelists. Lemon essential oil when supplemented at 150 mg/Kg diet improved L* values compared to control (P<0.05). A* value, also was higher in control than other treatment groups (P<0.05).

In this research, a total of 11,837 weight records of Baluchi lamb (6,030 males and 5,807 females) representing 300 rams and 3,694 ewes of Baluchi collected during 1978- 2008 from Abbas Abad breeding centre, Mashhad were utilized for investigating inbreeding trend and its effect on pre-weaning weight traits. The traits under consideration were birth weight (BW), weaning weight (WW) and pre-weaning daily gain (PWDG). Inbreeding coefficient of all animals was computed using CFC software. A linear model was applied for analyzing the data using SAS software. Among the animals, 8,903 (75.21%) were inbred. Average (standard deviation) of inbreeding coefficient were found to be 3.17 (3.94) and 4.22 (4.02) % for whole and inbred populations, respectively. Minimum and maximum inbreeding coefficients were 0 and 33.23 %, respectively. In whole population, average (standard deviation) of inbreeding coefficients were 3.20 (3.92) and 3.14 (3.95) % for male and female lambs,respectively. The corresponding figures were 3.07 (3.89) and 3.32 (4.00) % for single and twin lambs, respectively. Inbreeding depression was detected for BW, WW, W3 and PWDG in single male and single twin lambs and for BW in twin male lams (P<0.05). Annual trends of inbreeding coefficient were 0.117 and 0.022 % for whole and inbred animals which were found to be statistically significant (P<0.0001).

Biochemical compositions of ovarian follicular fluid may be influenced by blood serum metabolic changes and metabolic function of follicular cells. This study was performed to investigate some metabolic and hormonal changes of blood sera and ovarian follicular fluid of different-sized follicles in dairy cows. Follicular fluid from three groups of differentsized follicles; small (< 5 mm), medium (5-10 mm) and large (> 10 mm) in diameter were extracted, separately. Tail vein blood samples were obtained from 10 cows before slaughtering. Concentrations of hormones including IGF-1, estrogen, progesterone and concentrations of metabolites such as glucose, urea, cholesterol and triglyceride of blood sera and follicular fluid were determined using related commercial kits. For comparison metabolites and hormones concentration in blood sera and follicular fluid the linear mixed model, was used. This study showed a significant increase in glucose, estrogen and IGF- 1concentrations of follicular fluid by increasing of follicular size, but a significant decrease in urea, triglyceride and progesterone concentrations by increasing of follicular size. In addition, this study indicated a significant partial correlation for IGF-1(r=0.48), progesterone (r=0.47), urea (r=0.76) and cholesterol (r=0.74) concentrations between blood sera and follicular fluid. The results of this study showed that, biochemical compositions of follicular fluid is influenced by biochemical compositions of blood sera. Moreover, This study revealed a clear relationship between the follicular fluid concentrations of stradiolhormones, IGF-1, glucose, urea, cholesterol and triglyceride with follicle growth. Overall, the identification of essential biochemical compounds for growth and maturation of follicles, provides background to the requirement for enhancing the oocyte growth and ultimately to provide optimal reproduction.

Effects of different levels of cottonseed meal on milk composition and blood parameters of Zel ewes were investigated. Eighteen ewes with an average body weight of 39±0.5 Kg with at least, lambed once, were selected and divided to three groups of six ewes. A ration was formulated for control group containing 13% soybean meal, group one; 5% soybean meal and 15% cottonseed meal, group two; 25% cottonseed meal, group three. Milk sampling was carried out weekly for seven weeks. Blood samples were collected twice at the end of each month. Data were analyzed using Minitab by the procedure of General Linear Model (GLM). Results showed that there was not significant differences between control and treatment groups (P>0.05). Means of percentages of milk fat, SNF, protein, density and freezing point for control and treatment groups were 8.38±0.2, 8.89±0.24, 8.86±0.27 and 9.7±0.09, 9.43±0.19, 9.5±0.14 and 3.61±0.04, 3.46±0.65, 3.54±0. 04 and 30.32±0.53, 28.43±0.81, 29.6±0.53 and 58.34±0.64, 57.59±1.12, 54.92±1.78 respectively. Differences between milk yields and lamb body weights were not significant (P>0.05). Ewes milk yield and lambs body weight for control group and treatments one and two were 839±0.05, 773±0.04, 895±0.05 g/d and 10.5, 10.36, 11.08 (kg), respectively. Results also showed that blood parameters, except mean corpuscular hemoglobin concentration, were not significantly different between two months of experiment (P>0.05). The use of rations containing 15 and 25 percentage of cottonseed meal (830 PPM free gossypol) for feeding Zel ewes during lactation did not caused any negative effects on milk yield, milk composition and lambs body weight during lactation. Therefore, cottonseed meal can be used up to 25% in Zel ewes ration without any adverse effect on milk compositions and yield during lactation.