مجله علوم دامی ایران
سال سی و نهم شماره 1 (بهار 1387)

The present study was carried out to investigate the effects of different levels of canola meal eithr with or without phytase addition on laying hen's performance. A number of 288 layer hens (the strains of Hy-line W36) at the 60th week of age, selected as based on the same egg production percentage and body weight were, assigned to a factorial arrangement with a completely randomized design of 18 treatments (each treatment in 4 replicates). The factors included 6 levels of canola meal replacements (0, 20, 40, 60, 80 and 100%) and 3 methods of enzyme addition namely: 1-without enzyme 2-with enzyme (rations balanced with nutrient’s derived from the enzyme accounted for in feed formulation and 3-with enzyme and derived nutrients from the enzyme not taken into account in formulating the ration. The experiment was performed in three 28 day periods. The results indicated that feed intake was not affected by canola meal and enzyme and it was not affected by the interaction between enzyme and canola meal either. Phytase and canola meal addition to layer diet had no significant effect on mass egg production. Egg weight was affected by different levels of canola meal (P<0.01). The effect of interaction between phytase supplementation and canola meal in diet was significant on egg weight (P<0.05). Egg mass didn’t affect by canola meal, phytase and their interaction (P>0.05).There were no significant effects of different levels of canola, enzyme and their interaction on body weight changes, soft and cracked shell egg percentage and FCR (P>0.05). The effect of canola meal and phytase on toe ash as well as its Ca and P content was significant (P<0.01).

The effect of in ovo injection of olive leaf extract as a growth promoter antibiotic was studied on hatchability, day old chick weight, growth rate, feed conversion ratio, mortality and carcass efficiency. Three hundred and twenty eggs were divided into 4 groups, and injected on day 18. Treatments consisted of: 1- control (no injection). 2- injection of 1 ml of distilled water in air sac (DW), 3- injection of 1 ml olive leaf extract containing 0.75% of oleuropein (OL0.75) in the air sac. 4- Injection of 1 ml of olive leaf extract contain 0.9% of oleuropein (OL0.9) in air sac. No significant differences were observed in hatchability and in day old chick weight in eggs treated with olive leaf extract. OL0.9 treatment resulted in lowest mean live weight (P<0.05). Feed intake was not significantly affected by in ovo injection. The highest feed conversion ratio was observed in OL0.9 treatment during the final rearing period. Mortality was not found to be significantly different. Plucked carcass weight ecreased in eggs injected with 0.9% OL and the weight of bursa of fabricius was decreased in OL0.75 and in OL0.9 treatments (P<0.05). Other carcass parameters were not significantly affected by the treatment. It is concluded that a low dose of olive leaf extract may be recommended to promote egg quality, though more research is needed for further clarification.

One of the traits of the greatest financial impact on sheep production is the number of lambs weaned per ewe with FecB considered as the most well known major gene concerned with this trait. In order to conduct a marker assisted introgression (MAI) program the presence of FecB responsible mutation in Afshari sheep breeding flock was surveyed. Direct test to detect FecBB allele was conducted on 74 DNA samples through PCR-RFLP assay. Also the polymorphism content of the breeding flock was investigated by genotyping of one hundred randomly sampled animals at eighteen microsatellite loci selected on the chromosomes that did or did not carry introgressed gene. Except for MCMA26 monomorphic locus, other microsatellite loci exhibited a moderate level of polymorphism. As such a total of 102 alleles were detected with a mean number of 6 alleles per locus. A full characteristics assay of this set of seventeen polymorphic loci was carried out, generating allele frequency distributions that were employed to estimate genetic parameters of these loci, including expected heterozygosity, polymorphism information content (PIC), probability of identity (I), and discrimination power (D). The average expected heterozygosity was 0.72 (SD=0.07) and the average PIC were 067 (SD=0.08). Cumulative value of I corrected for linked loci was estimated as 3.128E-13. The results of microsatellite analysis indicated that, despite the selective breeding along with closed flock system over a number of generations, a relatively high level of allelic variability still exists in the breeding flock. Besides, the results of banding patterns from AvaII digestion of PCR products indicate the absence of FecB mutation in this elite flock. These observations demonstrate the applicability of marker data and would assist in making decisions on starting MAI program for an inclusion of FecB gene into the Afshari breed.

Honeybees like the other animal creatures require proteins, fats, carbohydrates, minerals vitamins and water for their maintenance, growth and reproduction. Normally they obtain their nutritional requirements from flowers but there are times when there aren’t sufficient flowers within reach they become in need of supplemental feeding. Some such nutritional substances as soybeans, glutens, yeasts, oilseed meals, milk powder, egg powder and others, are used as protein supplements, but their efficiency and digestibility are unknown as yet. In this research 6 diets comprised of 3 protein supplements (corn gluten, soybean meal and bakery yeast) at two levels of protein content (20 and 25%) along with 4000 kcal/kg GE of dry matter and sugar syrup (as control) were employed in a completely randomized design of 5 replicates (nucleuses). Data for body weight, carcass protein and fat percentage, as well as feed consumption were gathered and analyzed using SAS software. Results indicated that the difference between treatments was significant (P<0.01) for: feed consumption, feeding period, carcass protein, fat percentage a well as for body weight in worker group of bees.

Twenty four multiparous Holstein cows in their early stage of lactation with a mean of 59±20 DIM and a mean of 615±40.5 Kg of BW were employed in a complete randomized block design to evaluate the effects of different levels of sugar beet pulp in a partial replacement for alfalfa, the only source of forage in their previous diet (treat 1, 0% beet pulp and 35% alfalfa, treat 2, 6% beet pulp and 28% alfalfa, and treat 3, 12%beet pulp and 22% alfalfa) on milk yield and composition, dry matter intake, chewing activity, rumen and fecal pH, blood metabolites and digestibility of nutrients. The experiments were based on the new effective fiber hypothesis. Diets were formulated to contain 19.3% crude protein and 32.5% neutral detergent fiber.Cows were divided in three equal groups, each group receiving one of the diets in the form of TMR. There was not any treatment effect observed on DMI, milk yield and composition, and on fat corrected milk. Time of ruminating activities were significantly different among treatments (p<0.05).Chewing activity per kilogram of DMI, and forage NDF intake also were of significant differences(p<0.05). Rumen pH was of significant difference among treatments (p<0.05). Experimental diets did not show any significant effects on fecal pH, BW and BCS during the whole experimental period. Blood metabolites and digestibility of nutrients did not also differ among treatments.

A pedigree file of 382831 Holstein cows and bulls, collected from herds registered by Animal Breeding Center of Iran during 1967 to 1999, was used to calculate the inbreeding coefficient. The mean inbreeding coefficient for the whole population (male and female), on a base year of 1946, was 0.184%. The means for cows (94 percent of the whole population) and bulls (6 percent of the whole population) were 0.180% and 0.240%, respectively. Minimum inbreeding coefficient was zero, while the maximum values were 39.844, 39.844, and 25.780 for the whole population, cows and bull populations, respectively. In this population 9.5, percent of animals were inbred with a mean inbreeding coefficient of 2.175%. The regression coefficients of inbreeding on year for the whole population and for the population of cows were similar and positive (0.021%). This regression was positive for bulls but higher than that for the population of cows (0.026%).

The availability of the saturated DNA marker maps in livestock has made it possible to locate quantitative trait loci (QTL) in these domestic animals. The objective of this research was to investigate the principles of applying the simple regression for QTL analysis in paternal half-sib (PHS) design commonly used in livestock species. The theoretical aspects of the simple regression approach for QTL mapping in PHS design were studied. Simulation study showed that the power of QTL detection using the regression method increased as the sample size and QTL effect increased. Also increasing family size led to improved precision and accuracy of QTL parameters (estimates of QTL location and effect). The experimental beef cattle weaning data recorded on 366 animals from three half-sib families genotyped for 189 microsatellite markers were analyzed exploiting the simple regression approach. The results revealed two large QTL affecting weaning weight. The two detected QTL were located on Bovine chromosome 14 (BTA14) and (BTA16) at 29 and 81 cM, respectively.

This study was conducted to determine the effects of four different dietary levels of fish oil on performance, fatty acids composition, cholesterol and triglyceride in liver, breast and thigh muscle of broiler chicks. Two hundred and forty d-old male broiler chicks in a completely randomized design were allotted with four replicates. Broilers were fed isonitrogenous and isoenergetic diets containing 0, 1, 2 and 3% fish oil levels (treatments 1, 2, 3 and 4 respectively) ad-libitum in both starter (11 to 21 d) and growth periods. During the final week of the experiment (42 to 49 d) fish oil was removed from the diets. All of experimental groups were fed with the same diet to 10 d-old. The body weight gain, as well as feed efficiency were higher in broilers fed with fish oil as compared with control. The differences in feed intake were not significant. The fatty acid profiles in tissues were altered by fish oil. The effects of different levels of FO were not significant on cholesterol and triglyceride, except for the concentration of cholesterol in liver (p<0.05), that was lowered with 3% FO, but after withdrawal of FO from diet (49 days of age) the concentration of cholesterol and triglyceride significantly decreased in thigh and liver samples (p<0.05). Increased levels of fish oil clearly increased the amount of? -3 and? -6 polyunsaturated fatty acids in liver, breast an thigh muscle (p>0.05), and increased? -6 linoleic acid only at 42 days of age which was significant in liver tissue. In conclusion, the addition of FO in diet up to 2-3% and removing of FO during the last week and before slaughtering of the birds can be used for enrichment of meat.

The effect of three different levels of dietary electrolyte balance (DEB), in mean values of 114, 183 and 250 (mEq/kg), on broiler performance was evaluated. A number of 486 Arian male chicks were employed in a randomaized block design of three replicates and 54 chicks in each level replication. Diets were available to chicks ad lib and in three dietary phases. Serum Na+,K+, Cl- concentrations were measured at the end of each dietary phase. Leg bone(Tibia) ash content in each experimental group was tested at the end of day 42. In starter phase, feed intake and weight gain were decreased significantly by rising DEB (p<0.05). After that, no response was detected in on broiler performance in grower or finisher phases by an increase in DEB (p>0.05). In all the three phases, rise in DEB increased serum Na+,while decreasing serum Cl-, but having no significant effect on serum K+. As well, there was no significant differences observed among leg bone ash in different experimental groups (p>0.05) In addition, an increase in DEB did not have any effect on either Ascites syndrome or Tibia Dyschondroplasia. The results of this study have finally shown that DEB changes in a range of 114 to 250 mEq/kg of diet have no significant effect on broiler performance as observed throughout the experiment.

The effect of saline water and dietary betaine on growth performance of 576 male broiler chicks from 11 to 42 days of age, and on carcass composition (percentages of carcass, sartorial, breast, liver, abdominal fat and heart) of a sub sample of 96 birds was studied in a CRD experiment. Three dose levels of sodium chloride (0, 1000 and 2000 mg/L) and 4 levels of betaine (0.000, 0.075, 0.150 and 0.225 percent) were added to drinking water and basal diet, respectively. Feed was provided ad libitum and water in free access. Data showed that betaine supplementation and added NaCl in water increased and improved body weight and FCR, respectively (P< 0.05). Feed intake increased through a consumption of high levels of added NaCl, at the 11 to 21 and 29 to 42-d age periods(P< 0.01). Chicks which consumed higher levels of NaCl in water showed higher percentages of breast (P< 0.01). Interaction between betaine and water salinity was significant on body weight and FCR at 21-d age experimental period(P< 0.05). The data imply that betaine supplementation may have been involved in protection of intestinal epithelium against osmotic disturbance (saline water), improved digestion and absorption conditions of the gastrointestinal tract and amended the usage of nutrients.

Proliferation trend and polymorphism in 8 microsatellite dinucleotidalloci, a characteristic of Japanese quail, were described in the present study. The primers concerned were tested in 200 birds from Bonab Research Station. Samples were taken from four strains of Pharach, Golden, Tuxedo, and Panda. In total, all loci were polymorphic, except for GUJ0001 and GUJ0041 in respective strains of Panda and Tuxedo which were monomorphic. Various interpopulation variability parameters were studied for the tudy population. The average heterozygosity for all loci was 0.366. Furthermore the average rate of heterozygosity, without an inclusion of monomorphic loci, was estimated as 0.374. Maximum and minimum polymorphism Information content (PIC) and Shannon Information Index (I) were respectively obtained for GUJ0059 and GUJ0001 loci. Results indicate that in spite of selection for successive years along with closed mating system, there still exists a rather high level of polymorphism in the study population.

This study was carried out to determine the effects of gamma irradiation on dry matter (DM) and on crude protein (CP) degradation of rapeseed meal, using nylon bags and SDS-PAGE techniques. Ruminal nylon bags of either untreated or irradiated rapeseed meal at doses of 25, 50 and 75 kGy were suspended in the rumen of four non-lactating Holstein cows for up to 48 h. Intestinal crude protein digestibility was assessed using mobile nylon bag technique. Subunits of rapeseed meal proteins and disappearance patterns were traced and determined using sodium dodecyl sulphate polyacrylamid gel electrophoresis and densitometrical scanning. There were significant differences (P<0.05) observed (for DM and CP degradation characteristics and for effective degradability values) between untreated and gamma irradiated rapeseed meals. Gamma irradiation decreased wash-out fractions, degradation rate as well as effective degradability while increasing potentially degradable fractions of DM and CP. The effective DM and CP degradability of untreated and gamma irradiated rapeseed meal (at a rumen outflow rate of 0.05/h) were 67.8, 61.1, 54.1 and 50.5 % for DM, and 65.9, 53.4, 47.9 and 44.5 % for CP, respectively. According to slab gel analysis, rapeseed meal proteins were composed of two major components of napin and cruciferin, accounting for approximately 24 and 51 percent of the total meal proteins, respectively. Both proteins were multi-subunits. The molecular weights of 31.9, 26.0, 21.4, 19.5 kDa for cruciferin subunits and 8.0, 9.6 kDa for napin subunits were observed. Electrophoretic and densitometric analyses of untreated rapeseed meal protein residues revealed that napin subunits were degraded completely within 2 h, whereas the four subunits of cruciferin were not degraded even after 24 h of incubation. In gamma irradiated rapeseed meal, napin subunits were resistant until 12 h of incubation. The four subunits of cruciferin were not degraded even after 48 h of incubation. There were differences observed (P<0.05) between crude protein digestibility of untreated and gamma irradiated rapeseed meals. Crude protein digestibility of untreated, 25, 50 and 75 kGy gamma irradiated rapeseed meals were 72.3, 76.2, 78.5 and 80.1 %. The results finally indicate that gamma irradiation of rapeseed meal appears to be effective in decreasing ruminal protein degradability and increasing intestinal protein digestibility.