فصلنامه پژوهشهای تولیدات دامی
پیاپی 10 (پاییز و زمستان 1393)

The present experiment investigated the effect of different levels of dietary L-carnitine on electrocardiographic pathern of broilers reared at high altitude (2100 m). A number of 192 day-old chicks (Cobb 500) were selected from a group of 300 chicks and assigned to four treatments with four replicates of 12 birds. All chicks were raised on floor pen up to 42 days of age. Treatments composed of four levels of dietary L-carnitine (0, 50, 100, and 150 mg/kg). The control diet was formulated to meet the NRC (1994) nutrients recommendations. Results indicated that in Lead II,the amplitude of S-wave was significantly reduced (P<0.05) in broilers fed 50 mg/kg L-carnitine compared to the control. Such reduction in S-wave was also observed in Leads III and aVF. Amplituds of R-wave in Lead II and T-waves in all Leads did not show any significant difference among treatments. The right ventricular weight ratio tended to reduce in birds fed L-carnitine supplemented diets so that the difference between the control and 50 mg/kg L-carnitine treatment was significant (P<0.05). The results of this study showed that supplementary L-carnitine had beneficial effect on electrocardiographic response, as manifested in reduced S-wave amplitude and heart function in broiler chickens.

This experiment was conducted to examine the effect of different levels of protein (13 and 15%) and methionine (0.25, 0.30 and 0.35%) on performance and some egg indices in the late laying period of layer hens. Ninety six leghorn 80 weeks W-36 layers were used as a 2×3 factorial arrangement based on the completely randomized design. The results have shown that as methionine level was increased, the production percentage and egg weight were increased (P<0.05). Different levels of protein had no significant (P>0.05) effect on the production percentage and egg weight. Treatment effect on the production percentage and egg weight was significant (P<0.05), as birds fed diet containing 15% protein and 0.35% methionine had the highest production percentage and egg weight. Experimental treatments had no significant (P>0.05) effect on other parametes (cracked and soft eggs sell, yolk and albumen indices, egg area, egg weight to area ratio, yolk color, haugh unit, egg content and egg shap index). It can be concluded that the best levels of protein and methionine for egg production in the late laying period of laying hens are 15 and 0.35%, respectively.

An experiment was conducted to investigate the effects of dietary conjugated linoleic acid (CLA) and fish oil (n-3 rich) on the performance and fatty acid profile of breast and thigh tissues in broiler chickens. The dietary fats were included in the experimental diets at 7% for single fats and 3.5% + 3.5% of the dual mix of Luta CLA 60 and fish oil. The results of the present study showed that it is possible to enrich the broiler chicken meat with both the CLA and n-3 fatty acids. The diets containing 7% fish oil or 7% Luta CLA 60 supplement adversely affected the growth rate, carcass yield. The chickens fed the diet containing 3.5% fish oil + 3.5% Luta CLA 60 had an acceptable performance and noteworthy levels of valuable compounds, CLA and n-3 fatty acid, it seems that the enrichment procedure was more effective in the thigh than the breast. The findings of this study showed that the CLA supplement increased the CLA concentration in the breast and thigh tissues in a range of 161-163 and 207-219 per 100 g meat, respectively. This means that a 250 g meal of this enriched chicken meat can meet almost 25% of the daily CLA requirement of an adult human which considerably is higher than the normal CLA content of chicken meat.

An experiment was conducted to investigate the effect of probiotic, prebiotic and synbiotic on performance and Lactobacillus population in broiler chickens. Six hundred and thirty 1-d-old broiler chicks were used in a completely randomized design with 7 treatments and 6 replicates of 15 birds per replicate. Dietary treatments were; 1) basal diet (control diet without supplemental additives), 2) basal diet + probiotic of Perimalac, 3) basal diet + prebiotic of Technomos, 4) basal diet + prebiotic of fermacto, 5) basal diet + perimalac+ technomos, 6) basal diet + perimalac + Fermacto and 7) basal diet + symbiotic of Biomin IMBO. Parameters that were measured were: Feed intake, body weight gain, Feed conversion ratio and Lactobacillus population in ileum and cecum. In the starter period the body weight gain was significantly increased by the inclusion of combination of Perimalac + Fermacto as compared with the control (P<0. 05). In this experiment, feed intake was not affected by treatments (P > 0.05). During the starter period the treatments containing of Perimalac + Fermacto and Synbiotic Biomin, and during the grower and total periods the treatments containing Perimalac + Fermacto led to significant improvement in feed conversion ratio compared with the control group (P<0. 05). In the 23 and 42 days of the experiment, the treatments containing Fermacto alone, or Perimalac + Fermacto and Synbiotic increased the lactobacillus population in in the ileum and cecum in compared with the control group (P<0. 05). In conclusion, combination of probiotic and prebiotic improved the overall performance and increased intestinal population of Lactobacilli in broiler chickens.

This study was carried out to investigate the effect of Natuzyme plus enzyme on energy and protein efficiency for weight gain and metabolizable energy and protein digestibility of diets containing wheat and canola meal in broiler chickens. Seventy two day- old Arbor acres broiler were used in completely randomized design with 6 treatments and three replicates for starting (1-21 d) and grower (22-42 d) periods. Dietary treatments were 1. Corn- soy based diet (control), 2. Diet containing 30% wheat, 3. Diet containing 30٪ wheat +10٪ canola. These diets supplemented with enzyme (Natuzyme plus, 0. 350 g/kg) to provide 6 experimental diets. Results showed that Natuzyme Plus supplement significantly improve energy and protein efficiency for weight gain (P<0. 05). Enzyme addition to diets decreased the gut viscosity and increased metabolizable energy and protein digestibility of diets. The resulted of this study indicated that the supplementation diets containing wheat grain and canola meal increased the metabolizable energy and protein digestibility of diets and lead to improvement in energy and protein efficiency for weight gain, thus, it is recommended to supplement diets containing wheat grain and canola meal by plus natuzyme.

This study was carried out to determine the effects of supplementing fish oil and thyme extract on dry matter, organic matter and nutrient digestibility, chewing activity and rumen metabolites in Mahabadi goat kids. For this aim, twenty-eight Mahabadi goat kids (average initial BW of 17/8 +- 2/8 kg, 4-5mo) were randomly assigned to four treatments: 1) control (basal diet), 2) supplemented with 0.2% thyme extract, 3) supplemented with 2% fish oil and 4) supplemented with 0.2% thyme extract and 2% fish oil. Animals were kept in individual pens with self-mangers for 94 d. Addition of fish oil decreased NDF digestibility (P=0.01) and increased EE digestibility (P=0.05) versus the control. Ruminal ammonia concentration decreased by thyme extract (P=0.05). Addition of thyme increased acetate concentration (P=0.09) and acetate to propionate ratio (P=0.07). It was found that diets 2 and 3 significantly decreased protozoa count compared with diet 1 (P=0.05). Time to eat (minutes per day) was not affected by treatments, but chewing time significantly decreased by with thyme essence (P<0.05). The results of this experiment indicate that supplementation of goat kid diet with fish oil and thyme extract decreased NDF digestibility and increased EE digestibility and increased rumen acetate concentration.

This experiment was conducted to determine nitrogen fractions and ruminal dry matter and protein degradability of raw or heated (roasted or extruded) soybean seed. Samples were incubated for 2, 4, 8, 16, 24 and 48 h in the rumen of 4 cannulated Kurdish male lambs (50 ± 3 kg BW). N itrogen fractions of samples were measured by chemical methods. Results showed that extruding decreased non-protein nitrogen (NPN) and acid detergent insoluble nitrogen (ADIN) in soybean seed. In compared with raw soybean seed, roasting decreased and increased buffer soluble nitrogen and neutral detergent insoluble nitrogen (NDIN), respectively. Lowest NPN and ADIN were observed in extruded soybean seed. Soybean seed extruding decreased and increased the rapidly degradable fraction (a) and the slowly degradable fraction (b) of protein, respectively. Roasting and extruding significantly decreased the rate of degradation (c). Effective degradability (ED) of soybean seed dry matter and crude protein significantly decreased by heat processing. Roasting and extruding had no effect on degradability potential of soybean seed dry matter and crude protein. The results of this experiment showed that heat processing significantly altered nitrogen fractions and decreased ruminal protein degradability of soybean seed. Also, extruding was better than roasting because it decreased NPN, ADIN, a fraction and ED and increased b fraction of soybean seed protein.

The objective of this study was to compare dry matter degradability of some feedstuffs including soybean meal, canola meal, barley grain, corn grain, alfalfa hay and corn silage by in vitro and in situ techniques. The in vitro method includes the ruminal digestion stage of the in vitro dry matter digestibility technique. Significant differences were observed between two methods in the estimation of the immediately soluble fraction for all feedstuffs except for canola meal (P<0.05). Two methods had significant differences with each other for estimating the potentially degradable fraction of soybean meal, barley grain, alfalfa hay and corn silage (P<0.05). It was not observed significant differences between two methods for estimating the degradability rate of the feedstuffs except for forage feeds. But, high correlations were observed between two methods in the estimation of the potentially degradable fraction (r=0.72), rate of degradability (r=0.89), potential of degradability (r=0.98) and the effective degradability (P<0.01). The results showed that there were significant differences between two methods in the estimation of degradability parameters, but the observed high correlation coefficients for some degradability parameters could indicate the relative ability of the innovative method.

The objective of this study was to evaluate the apoptotic effects of increasing granulosa cell density and increasing estradiol on relative gene expression associated with apoptosis factors (Bcl-2, Bax and GADD45β) and cell cycle (CCDN-2). For this reason after collecting ovaries of cows from an abattoir, granulosa cells were separated from 4- to 8-mm follicles. Then, viable cells were counted and granulosa cell samples were cultured for 6 days. Treatments were included 1) 500,000 cell/1000 ml liquid culture (Control), 2) 500,000 cell/500 ml liquid culture (apoptotic group: increasing cell density cause apoptosis), 3) 500,000 cell/500 ml liquid culture and estradiol from day two of culture (apoptotic group+estradiol). Also, expression of genes associated with apoptosis factors and cell cycle, and estradiol of samples were evaluated. Results showed relative gene expression of Bax and GADD45β was greatest in apoptotic group compared to two other groups; but, with adding estradiol expression of these two genes decreased to control level. Bcl-2/Bax ratio decreased in apoptotic group compared with two other groups; while, adding estradiol significantly increased this ration, but, still it was lower than control group. Relative gene expression of CCDN-2 was lowest in apoptotic group compared to two other groups; but, no significant difference was observed between control and estradiol group. Overall results of the present study showed that estradiol can protect granulosa cells against apoptosis induced with increasing in cell density and probably it was done through progression of the cell cycle from G1 to S stage.

The objective of this study was to investigate the effect of different levels of egg yolk on quality of Zel ram spermatozoa in pre and post freezing conditions. Semen samples were collected from 4 healthy and mature rams using an electro-ejaculator and suitable samples were mixed with Tris extender in a ratio of 1:4 semen and samples were assessed, after cooled to 5-0C. Then, 0.5 ml of straws were filled with diluted semen. At first, straws were frozen on liquid nitrogen vapor, then kept in liquid nitrogen and after 10 days straws were thawed to investigation of morphological characteristics, viability, motility and progressive motility of spermatozoa. This experiment was carried out on the basis of completely randomized design with 3 treatments include levels of egg yolk 10, 15 and 20% and 9 replications. Results showed that the effect of egg yolk on viability, motility, progressive motility, normal spermatozoa and recovery percentage of spermatozoa were not significant (P>0.05), but the higher quality of spermatozoa and supply of energy source given in 20% egg yolk for lifespan, despite the absence of significant, if price of egg yolk is economical, 20% egg yolk can be used in Tris extender for maintaining and long term storage of Zel ram spermatozoa.

Besides their role in making energy, polyunsaturated fatty acids can affect on ovarian follicles and corpus luteum by providing the precursors required for the synthesis of signaling molecules such as steroids and prostaglandins. The effects of α-linolenic acid (ALA) on developmental competence of oocytes in goats were evaluated in this study. Initially, ALA content of follicular fluid of small and large follicles was determined using GC–mass chromatography. Our results indicated that the ALA concentration was in a range of 64.6 to 100.6 μM for small and large follicles, respectively. Then, based on preliminary results, goat oocytes were matured in presence of 0 (Control), 10 (ALA-10), 50 (ALA-50), 100 (ALA-100) and 200 (ALA-200) μM of ALA. Twenty four hours after in vitro maturation (IVM), oocytes in each group were evaluated for their cumulus cell expansion and also for their maturation rate. Furthermore, matured oocytes were treated for parthenogenetic activation and the cleavage and blastocyst rates of control and ALA-treated group were recorded at day 3 and 8 post-activation. Data from each stage were recorded and analyzed via Compare Means Test and/or chi-square analysis using SAS software. Supplementation of maturation media with different concentration of ALA had no effect on cumulus cell expansion except in the highest concentration (ALA-200) that decreased the cumulus cell expansion (P˂0.05). Our findings indicated that maturation rate was higher (P˂0.05) in ALA-50 group as compared with the control group (68.1% vs. 58.2%). Moreover, supplementation of maturation medium with 50 μM ALA improved the cleavage rate (65.2% vs. 52.8%) and blastocyst rate (25.1% vs. 16.7%) as compared with the control group (P˂0.05). Collectively, our results showed that treatment of maturation medium with optimum concentration of ALA had a beneficial effect on oocyte maturation by increasing the maturation rate and this in turn, can stimulate the embryonic development.

Recently, mutations with major influence on ovulation rate and litter size were identified in TGFβ superfamily ligands and receptors. This study was conducted to identify polymorphisms in GDF9 and BMP15 genes in Dalagh sheep breed. One hundred mature ewes from two flocks in Golestan province were genotyped for the GDF9 (G1) and BMP15 (B4) variants. Two fragments of 462bp and 153bp of GDF9 and BMP15 genes were amplified by PCR-RFLP method. PCR product was digested using HhaI and DdeI endonuclease restriction enzymes. The results of the digested PCR products, did not confirm mutation at position B4 but Polymorphism was observed at G1position. The heterozygote genotype frequency in the population was estimated at 15%.

OPN gene is located in the middle of chromosome 6 and it is reported that this gene is essential for the growth of mammary glands and lactation. UTMP gene is located on chromosome 21 and it plays a role in embryo survival rates and fertility rates. Studies have also shown that these two genes have a significant association with milk production traits and health traits. The aim of this study was to investigate the polymorphism of OPN and UTMP genes in Iranian Holstein Bulls. Genomic DNA of 100 bulls was extracted from semen samples. Primers were designed with Oligo software and utilized for amplification of 826 bp of OPN gene and 568 bp fragments of UTMP gene. PCR products were digested with BsrI enzyme. Results had shown that genotype frequencies CC, CT and TT of OPN gene were 16.69, 48.62, and 34.69, respectively and the allelic frequencies of C and T were 0.41 and 0.51, respectively. Genotype frequencies2 observed for genotypes AB, BB, BC and CC of UTMP were 0.27, 0.49, 0.13 and 0.11 respectively and genotypes AA and AC were not observed in studied population. Results showed that A, B and C allele frequencies were 0.135, 0.69 and 0.175, respectively. The x2 test has shown deviation from H ardy-Weinberg equilibrium for OPN and UTMP genes in the studied population. With respect to the favoralde effect of both genes on milk production traits, the allelic frequency of these genes could be changed in order to breeding purposes.

Twinning trait is an important trait in sheep breeding. Reproductive traits differ greatly across sheep breeds, but also between sheep in a single flock. Identification of ewes with higher twinning rate and more raised lambs per year is an important parameter for breeding and farming success. A genome-wide haplotype association study, using 42,416 Single Nucleotide Polymorphisms (SNPs) was conducted to identify genomic regions affecting twinning rate in Baluchi sheep. We also studied LD patterns in this population. Blood samples from a total of 96 sheep from two herds and data on their twinning rate during the first four parities were collected. Animals were genotyped using the IlluminaOvineSNP50K BeadChip assay. Genetic stratification and herd effect were included as confounding effects and fitted into the statistical analyses. Haplotype based GWAS for twinning was performed with the first MDS component and herd effect as covariates. To control the Association with twinning rate was tested using the software PLINK. Suggestive associations were identified for SNP on chromosomes 1, 10 and 15. LD was evaluated by measuring r2 between all pairs of loci. For SNPs up to 10 kb apart, the average r2 was 0.33, for SNPs separated by 200–500 kb the average r2 was 0.086. The extent of LD in Baluchi sheep extends over much more limited distances than reported in dairy cattle and seems to be similar to other ovine populations. Further studying of these regions in validation studies will help the identification of candidate genes for twinning rate in sheep.

In this research test-day records of milk, fat and protein yields of first lactation of 11368 Holstein cows were used to comparison of estimated genetic parameters by restricted maximum likelihood method based on single trait and multiple trait random regression models. These data were collected from 133 herds during 2001 to 2010 by Cattle Breeding and Dairy Product Improvement Center. Heritability of milk, fat and protein yield during lactation based on single trait model were ranged from 0.107 to 0.226, 0.049 to 0.145 and 0.087 to 0.239, respectively, but by multiple trait model these values were ranged from 0.109 to 0.223, 0.051 to 0.118 and 0.084 to 0.190, respectively. Minimum genetic and permanent environmental variances were in peak to mid lactation. Assuming independent of traits during lactation, permanent environmental variance was underestimated and heritability was overestimated nearly to end of lactation. Genetic correlations between production traits during lactation were not constant and it was higher at the end of lactation. However, the largest genetic correlation was observed between milk and protein yield.