مجله علوم دامی ایران
سال چهل و سوم شماره 4 (زمستان 1391)

This experiment was performed to investigate the effects of propolis and chromium picolinate on performance and immune response of broiler chicken under heat stress conditions. Treatments included different levels of propolis (500, 1000, and 1500 mg/kg) and chromium picolinate (1500 µg/ kg) along with a control group. A completely randomized design was taken into account with 4 replicates of 10 Ross (308) male broiler chicks per treatment under heat stress conditions (34 ±2°C, 5 hours/day). The chicks received treatments from 1 to 42 days. Birds fed 1500 mg/kg propolis had significantly higher feed intakes (p<0.01). Weight gain (p<0.01) and feed conversion ratios (p<0.05) were significantly more pronounced than the control for different levels of propolis and chromium picolinate. Experimental diets did not show any significant effect on blood glucose and insulin levels. Chicken fed 1500 mg/kg propolis had more lymphocytes than control did (p<0.05). There were not any significant differences observed in weights of different organs, except for edible carcass and bursa of Fabricius relative weights that were recorded higher than those of control for different levels of propolis and chromium picolinate (p<0.01).

The effects of probiotic (Protexin) and formic acid were studied on humoral and cellular immunity in 200 Cobb broiler chicks in a completely randomized design of with 4 treatments and 5 replications (10 observations per replicate). Control group (C) did not receive any other than the base treatment. The chicks in the second (P), third (F) and forth (P+F) groups were fed with feed, which contained 0.1 g/kg Protexin, 0.8% formic acid vs. 0.1 g/kg Protexin + 0.8% formic acid in their diets, respectively. Daily feed intake weight gain. and feed conversion rates were recorded. The birds were immunized with Sheep Red Blood Cells (SRBC) on days 8 and 22 of age while serum antibody levels (produced in response to SRBC) being assessed through Hemagglutination Assay Technique on days 21, 28, 35, and 42. Skin response to Phytohemagglutinin-P (PHA-P) injected intradermally on day 16 was recorded 24 and 48 h following after injection. The weights of thymus and bursa of fabricius were also recorded following slaughter. The results indicated that daily feed intake and feed conversion rates decreased in the treatment groups (P<0.05). Groups P and P+F increased in mean of total anti-SRBC titer (P<0.05). IgG and IgM titers were not affected by experimental groups. Protexin and formic acid increased cellular immunity upon PHA-P injection after 24 and 48 h (P<0.05). Thymus and bursa of Fabricius weights increased in treatment groups (P<0.05). It is concluded that protexin improved cellular and humoral immunity; formic acid improved cellular immunity but not the humoral immunity. Synergism effect of protexin and formic acid was not observed.

The effects of different levels of Whole Cottonseed (WCS) on feedlot performance and morphology of small intestine were studied in a completely randomized design with four diets containing 0, 4, 8 and 16 percent WCS on 20 Chaal male lambs for 90 days. The metabolisable energy and proteins contents of rations were equal. Number and dimensions of different types of villi and depth of crypt gland were evaluated. Different levels of WCS in the diet had no significant effect on body weight gain and feed conversion ratio, but the sheep consumed diets containing 4 % WCS more than they did the other diets (p<0.01).. The effect of diet was significant only on the number of leaf shape villi. (p<0.01). The difference number of all types of villi in different places of intestine sampling (duodenum, jejunum, ileum), also was significant. Villus dimensions and depth of crypt gland were affected by diet and sites sampling. This experiment showed that, WCS can increase villus heigh:crypt depth ratio and it could be included 16 percent of the fattening male lamb’s diet.

Eight male lambs each aged approximately 11 months and having a body weight of 32.5 ± 2.5 kg were selected as experimental samples in the ongoing experiment. For the supplemented group, Monensin was fed at 22 mg/lamb per day. Relationships between dietary characteristics and fecal as well as urinary nitrogen losses were examined using data from the two treatments. Microbial N production was estimated using Non-linear Multiple regression in which the metabolizable energy and nitrogen intake variables formed part of the equation (r 2 = 0.94). The results revealed that Monensin supplement did not have any significant effect on DMI, ADG, FCR and blood parameters (P>0.05). But, protozoal population, rumen and urine pH, creatinine clearance and glomerular filtrate rate were significantly affected by the treatment (P<0.05). Metabolic Fecal Nitrogen (MPN) ranged from 124 to 181 mg/kg W0.75, and increased by increasing levels of Digestible Organic Matter (DOM) intake (r = 0.79). Endogenous Urinary Nitrogen (EUN) showed an opposite behavior, decreasing from 215 to 158 mg/kg W0.75, which could be attributable to urea recycling to the large intestine being enhanced by increasing hindgut fermentation with increasing DOM levels, as the composition of urinary nitrogen suggests. Total endogenous nitrogen was estimated at 339 mg/kg W0.75, which is very close to AFRC recommendations (350 mg/kg W0.75).

A study was carried out to examine the effect of different levels of Herbal methionine and DL-methionine on the growth performance and immunocompetence of broiler chickens fed on a corn-soybean meal diet. A total of 225 old male broiler chickens (Ross 308) were used as experimental samples in a completely randomized design. They were randomly assigned to 9 treatments each of 5 replicates in every experimental unit (cage). Treatments included basal diet supplemented increasingly with Herbal methionine and DL-methionine during three growth periods of the birds. Treatments included: T1: basal diet without any additional methionine, T2: basal diet plus 0.07, 0.06, 0.05, T3: basal diet plus 0.15, 0.11, 0.10, T4: basal diet plus 0.22, 0.17, 0.14, T5: basal diet plus 0.29, 0.23, 0.19 % DL-methionine for starter, grower and finisher periods respectively, T6: basal diet plus 0.07, 0.06, 0.05, T7: basal diet plus 0.15, 0.11, 0.10, T8: basal diet plus 0.22, 0.17, 0.14, T9: basal diet plus 0.29, 0.23, 0.19 % Herbal methionine for starter, grower and finisher periods respectively. Feed intake and body weights were recorded during the three experimental periods and then, feed conversion ratios calculated. To investigate the immunocompetence of birds at 28 and 42 days of age, the following two tests were carried out: 1) response to antibody titer against antigen of Sheep Red Blood Cells (SRBC) and 2) response to dilution of 1-choloro 2-3- dinitrobenzene (DNCB). The results revealed that the maximum finisher body weight gain was related to the two highest levels of DL-methionine and Herbal methionine with significant differences as compared with the other treatments, while the highest level of DL-methionine causing minimum finisher body weight gain. Birds fed the basal diet plus 0.15, 0.11, 0.10 % DL-methionine for starter, grower and finisher periods respectively and also, the basal diet plus 0.22, 0.17, 0.14 % Herbal-methionine for starter, grower and finisher periods respectively, exhibited the most desirable performance and immunocompetence. Thus, according to the obtained results, it seems that Herbal methionine could in effect replace DL-methionine.

This study was conducted to evaluate the effects of extruded linseed on milk production, dry matter intake and reproduction performance of 300 Holstein lactating cows (35±15 days in milk; 41±9/8 Kg/day of milk production). Cows were utilized in a completely randomized experimental design, comprised of: 2 treatments (concentrate containing 7 percent extruded linseed vs control) with a number of 150 cows per treatment. Cows were fed a balanced total mixed ration (610 g concentrate /kg DM and 390 g forage /kg DM) 3 times daily, and milked 3 times daily. Cows in group 1 were fed TMR without extruded linseed (control); cows in group 2 were fed totally mixed ration with TMR with containing extruded linseed (7 percent of concentrate). Extruded linseed did not affect milk production and dry matter intake (P>0.05). Treatment of feeding cows with extruded linseed caused them to have higher Pregnancy rates, lower number of open days, and fewer number of inseminations (P<0.05). It was concluded that extruded linseed can increase reproduction performance of Holstein dairy cows in their early stages of lactation

The aim followed in this study was to use the multi and single trait analyses for a prediction of genomic and traditional breeding values and to make a comparison of the accuracies of these methods. A base population of 100 animals (50 males and 50 females) was randomly mated for 50 generations to create linkage disequilibrium among loci. The simulated genome size was 10 Morgan, equally divided among 10 chromosomes. On each chromosome, SNP markers were evenly located and QTLs randomly distributed over the genome. Single and multi-trait analyses were employed to BLUP estimate the SNP effects. Genomic breeding values of the animals, for each trait, amounted to the sum of SNP effects for all the loci. Results indicated that the accuracies of genomic breeding values were higher than those of traditional ones. Accuracy of breeding values increased as heritability, map density and the number of individuals, in training population, increased. High genetic correlation between the two traits led to the increased genomic and traditional breeding value accuracies.

Throughout the current study, the appropriate function for a description of egg production curve in a commercial broiler dam line was determined through fittings of a number of six mathematical models, namely: incomplete gamma function (WM): modified incomplete gamma function (MWM): compartmental function (CM): modified compartmental function)MCM): polynomial regression function of Ali and Schaeffer Function (AS): and logistic-curvilinear function (LF). For each model, the parameters were estimated through Gauss-Newton method (implemented in NLIN procedures) in SAS software. The models were compared as based on the adjusted R-square (), Mean Squared Error (MSE) and Akaike Information Criteria (AIC). The results indicated that the compartmental function was of the least MSE and AIC and was therefore the most appropriate function to describe the egg production curve in the current study population.

To investigate the possibility of using ultrasound to estimate carcass composition, 38 Moghani male lambs were made use of. Subcutaneous fat depth (USFT) and longissimus dorsi muscle depth (ULMD) and area (ULMA) were assessed in the site between 12th and 13th ribs by using ultrasound equipped with an 8 MHz probe. The lambs were then slaughtered. Carcasses were cold stored at 4°C for 24 hours and then the corresponding measurements performed on the carcasse. The right half of each carcass was dissected to determine carcass composition including muscle, fat and bone. The results revealed that correlation coefficients between the measurements of USFT, ULMD and ULMA and the corresponding carcass recordings were 0.51, 0.71 and 0.92, respectively. Also the correlation coefficients between ULMA and the levels of muscle and bone were recorded as 0.33 and 0.48, respectively. Coefficient of determination in simple regression equation to estimate the hot carcass weight, cold carcass weight, carcass weight without fat-tail and subcutaneous fat depth as based on body weight were 0.85, 0.87, 0.77 and 0.13, respectively. Multiple regression models while using USFT, ULMD, and ULMA in addition to body weight promoted the R2 to 0.86, 0.88, 0.83 and 0.53, respectively. Also the coefficient of determination in simple regression equation to estimate carcass longissimus dorsi muscle area employing only ULMA and carcass longissimus dorsi muscle depth with an employment of only ULMD were recorded 0.86 and 0.50, respectively. The results show that the use of ultrasound to estimate carcass composition on live sheep can be done successfully. Therefore important traits can be asessed and made use of in breeding programs without the need to slaughter killing the animal.

Efficiency is defined as a concept that determines the input output ratios in an economic system. Data Envelopment Analysis method is a useful tool to estimate the efficiency of a unit. The purpose of this study was to estimate technical efficiency and to determine Return to Scale of Holstein cattle farms in Guilan Province. Therefore, the information including the number of labor and dairy cows as well as the level of feed and milk production related to twenty Holstein cattle farms in Guilan province were collected in 2011 and their efficiencies estimated as based on production and economical performances. Among all the studied units, four were around 100 percent efficient while the remaining ones suffered from various degrees of inefficacy. The average technical efficiency was estimated to be 0.726, suggesting that each production input, including the number of labor, the amount of forage and concentrate, could be reduced on average by about 27.4 percent without any reduction resulting in the current level of production. Technical efficiency difference between the most efficient unit and the least one was 65.4 percent. Seventy percent of the Holstein cattle farms studied benefited from increasing returns to scale, 20 percent had constant returns to scale and 10 percent decreasing returns while. Therefore, in 70 percent of these units, given their input management as efficient, development of activity dimensions in terms of the number of labor and feed consumption could lead to even more production through an increasing return to scale.

The current study was conducted to investigate the effect of short-term selection in Japanese quail for its 4-week body and breast weights. Two selected lines, one for selection of body weight based upon in. breeding values (line 1) and another for breast weight based on between family selections (line 2) were randomly selected from a base population. In each generation, 39 sire and 78 dam-birds were taken as parents in each line and for the next generation. The number of selected replacements in line 2 was less due to decreasing population size. Data were collected over 2 consecutive hatches for 4 generations and selections responses determined for 3 generations. The levels of improvement of 4-week body weights in line 1 were recorded 14.4, 12.6 and 8.1 grams respectively for the 3 generations. Correlated response to breast weight in line 1 was 4.1, 3.6, and 3.2 grams in generations 2, 3, and 4, respectively. Directed selection from 4-week breast weight in line 2 led to improvements of: 4.0, 3.5 and 2.7 grams in generations 2, 3 and 4, respectively. Also, correlated responses for body weight in this line were recorded as: 14.5, 13.0 and 7.4 grams in generations 2, 3 and 4, respectively. There were significant differences in body weight and carcass traits between sexes and also in generations 2 and upward (P<0.01) but not for percentage components of carcass. Higher figures were obtained for femals than for males. Selection for 4-week body weights in line 1 and 4-week breast weights in line 2 improved Feed Conversion Ratios (FCR) for about 0.16 and 0.19 units over the selected periods, respectively. Genetic and phenotypic correlations between body and breast weights in line 1 were 0.90±0.12 and 0.73±0.06 and for line 2 they were: 0.85±0.06 and 0.82±0.02, respectively. Results obtained from this study do not support the in-between family selection as a tool to increase breast weight selection as based on body weight, due to its high genetic correlation with body weight (0.85-0.90), can be employed as a proper selection criterion for improving carcass traits, including breast weight.

Regions on three ovine chromosomes (OAR1, OAR5 and OAR25) were selected to study quantitative trait loci (QTL) segregating for wool traits in Baluchi sheep. A total of 503 progeny from 13 half-sib families were genotyped for 15 microsatellite markers. The average number of progeny per sire was 38 and ranged between 16 and 59. Data were collected from Research Centre on Baluchi breed in 2009 and 2010. A total of 14 wool traits were analyzed and phenotypes were corrected for fixed effects of birth year, sex, flock, litter size and shearing date (year and season). The QTL analyses were performed using regression-based interval mapping with two model of one-QTL and two-QTL model. The results revealed 6 QTL on OAR1 for fiber type traits (hetero-type True and Kemp fibers type percent in fleece), coefficient of variation of fiber diameter and greasy and clean fleece weight, two QTL on OAR5 for clean fleece weight and hetero-type wool and 7 QTL on OAR25 for fiber type traits (HET, KEMP and TRUE), greasy and clean fleece weight, coefficient of variation of average fiber diameter and the percent of fiber diameter with 40 to 50 µm.

The aim followed in this study was to investigate the effects of soybean oil (high in C18:2 n-6, an omega-6 fatty acid) and fish oil (high in EPA 20:5 n-3 and DHA 22:6 n-3, omega-3 fatty acids) on meat quality and on the fatty acid profiles in goat kids. Twenty-four male kids were allocated through stratified randomization and on the basis of body weight (19.43±1.2 kg) into three equal groups. Each group received one of three dietary treatments as follows: control (PO), Soybean Oil (SO) or Fish Oil (FO). Forage/ concentrate ratios in the diets were 30/70 with all the three diets being isonitrogenous and isocaloric, but containing different oil sources. Palm-oil (high in 16:0 a saturated fatty acid), soybean oil and fish oil were supplemented at 2% DMI to CO, SO and FO diets, respectively. After being fed for 12 weeks, kids were slaughtered, longissimus muscle was sampled out, and then meat quality and fatty acid profiles recorded. The acidity (PH) water holding capacity, colour, shear force and sensorial attributes were not affected by treatments. However, inclusion of soybean oil in the diet increased C18:3, C18:2 and P/S ratios in intramuscular fat (P<0.001). Fish oil increased the proportions of C20:5 n-3 and C22:6 n-3 while C20:4 n-6 and n-6/n-3 ratios in the intramuscular fat (P<0.001). The results demonstrated that supplementation of either soybean or fish oil at 2% DM can affect the intramuscular fatty acid profile in kids.