مجله تحقیقات دام و طیور
سال سوم شماره 1 (1393)

Different additivessuch asantibiotics, enzymes, probiotics, prebiotics,synbiotics(peribiotics+probiotics), organicacidsand their derivativescanbeaddedtopoultry feed tostimulate growth,booster theimmune system, relieve foodshortagesanddisease prevention. Inrecentyears,the use of feedadditives with plant origin has increased inpoultry industry and that their benefit their effects on thepoultry performancehave been reported. Thisstudywas conductedina completely randomized design with treatments including cardamom seed extract in threelevels,synbioticandcontrol diet.The resultsindicated significant differencebetweentreatmentgroupsin terms ofaveragefeed intake,average weight gainandfeed conversion implyingthata positiveeffect of cardamomandsynbioticon thegrowth rate. Also changes incholesterol, triglycerides, HDL, LDL, H/Lratiowere observed. No changesinglucose levels, hemoglobinandhematocrit values were detected between treatment groups. Antibody titers againstinfectious bursal disease virus (IBDV) was significantly different betweenexperimental groups andcontrolgroup indicating a positive effect of cardamom seed extract and synbiotic on chicken’s immune system.

This experiment was carried out to determine the effect of organic acid (OA) on some serum metabolites, plasma minerals and some tibia characteristics of Ross 308 broiler chicks. A total of 128 broiler chicks were used in a completely randomized design with four treatments, four replications and eight chicks per each replicate. The treatments were: T1: basal diet (no additives; BD). T2: BD + 0.1% OA, T3: BD + 0.2% OA and T4: BD + 0.3% OA. The results showed that serum concentrations of metabolites including urea, cholesterol, total protein, albumin, globulin and also plasma minerals, including calcium, phosphorus, magnesium and iron at 21 and 42 days of age were not significantly affected by organic acid. Blood triglyceride concentration at 42 days of age significantly affected by treatments so that treatment containing 0.2% organic acid had the highest levels of blood triglyceride and control and treatment containing 0.3% organic acid had lower blood triglyceride level and this difference was statistically significant (P<0.05). Calcium, phosphorus and magnesiumpercentage of tibia of broilers were not significantlyaffected by dietary treatments. Percentage of ash, relative weight, relative length, internal diameter and thickness of the tibia in broiler chickens were not significantly affected by dietary treatments. The results obtained from this experiment indicated that use of organic acid was not able to influence blood parameters and tibia characteristics of broiler chickens.

This experiment was undertaken to evaluate the effects of wheat bran, enzyme and probiotic on performance, egg traits, biochemical parameters and blood cells of commercial laying hens. A total of 384 Hi-line (W36) laying hens was used in a completely randomized design with factorial arrangement (2*2*2) with two levels of wheat bran (0 and 10%), two levels of combo multi-enzyme (0 and 0.05%) and two levels of probiotic protexin (0 and 0.005%).There were eight treatments, four replicates and 12 birds per replicate for a period of 12 weeks (65-76 weeks). Using 10% wheat bran in diets improved the egg weight, egg production percentage, egg mass, feed conversion ratio and egg yolk color index (P<0.05).This treatment had no any significant effects on the amounts of feed intake, blood biochemical parameters and blood cells. Using enzyme decreased the amount of egg weight but with no significant effects on egg traits and blood metabolites. Using probiotic in the diet improved the performance and egg color index, but it had no significant effects on blood metabolites. Two way interactions between wheat bran and enzyme, between wheat bran and probiotic, between enzyme and probiotic, and three way interaction between wheat bran and enzyme and probiotic had significant effects on performance and egg traits but blood metabolites was not significantly changed. It could be generally concluded that, using 10% wheat bran with 0.05% of Combo multi-enzyme and 0.005% of probiotic (protexin) could improve the performance and egg traits without having effects on blood metabolites.

Production of milk with a low bacterial count starts at the level of dairy farm and depends on management practices applied by dairy farmers. The main aim of this research was to study the effect of dairy farmer's management practices on reduction of milk bacterial count. A survey method was used. The population under consideration comprises of all industrial dairy farmers in Shiraz and Marvdasht districts who were delivering their milk to Pegah- e- Fars dairy processing factory. Based upon Morgan table, sample size was determined and it was set to be 175 subjects. A questionnaire was utilised for collecting required information of dairy farmers. Total bacterial count of each dairy farm was obtained by the results of total bacterial count test of Pegah- e- Fars dairy processing factory. The results revealed that total count of the samples was not at an appropriate level. Cleaning of milking machine as well as level of physical development of the dairy farms had negative effects and significant relationship with total bacterial count of milk. Mean total bacterial count of milk were compared between different groups and based on the results, some recommendations were suggested for reduction total milk bacterial count.

The records obtained from fourteenth generation of Azarbaijan's native chickens were used to estimate the genetic and phenotypic parameters for internal quality characteristics of eggs. Performance of 960 chickens and internal quality of 2000 eggs were collected. Genetic and phenotypic parameters were estimated by a set of single-trait and multiple-trait animal models by restricted maximum likelihood (REML) using AIREMLF90 software. Means for traits of Haugh unit, albumen height, albumen weight, yolk weight, yolk width and yolk index were 62.08%, 4.26 mm, 33.29 g, 16.88 g, 40.63 mm and 35.91%, respectively. Heritabilities for the traits were 0.38, 0.3, 0.38, 0.36, 0.27 and 0.22 (by single-trait model) and 0.71, 0.65, 0.71, 0.75, 0.62 and 0.56 (by multiple-trait model). The highest genetic correlation was found between Haugh unit and albumen weight (0.96). Generally, heritabilities estimated by multiple-trait animal model were higher than that of obtained by single trait model and that based on high genetic correlations between traits, the lattermodel is more valid than the former model. Regarding the high value of heritability for albumen weight obtained by multiple-trait model, selection for this trait could result in improving Haugh unit and,as a consequence, quality of Azarbaijan’s native chicken eggs.

A total of 160 Ross 308 male broilers were used in a randomized complete design, with five treatments and four replicates for each treatment (eight chicksper pen),from 7 to 42 days of age. Feed intake (FI), body weight (BW), weight gain (WG) and feed conversion ratio (FCR) were measured during the experiment and carcass yield, relative weight of internal organs were measured at the end of the experiment. A corn-soybean-based diet was used as the basal diet (control, treatment 1). The basal diet was supplemented with an antibiotic growth promoter (Oxytetracycline, 150 g/ton, treatment 2), commercial organic acid (Orgacid, 0.3%, treatment 3), probiotic (Protoxin, 150 g/ton, treatment 4) and prebiotic (Mannanoligosaccharides, 2 kg/ton, treatment 5). Chickens fed with diets containing organic acids had the lowest FI, as well as the best FCR as comparedto other treatments. Numerically, chickens fed with diets containing probiotics had the highest WG during the period of 22 to 42 daysof age, but inclusion of antibiotics caused a non-significant increase in WG. On age 42d, chicks fed with basal diet had the highest BW. However, the lowest BW was relevant to the diet containing organic acids. The relative weight of heart and wing showed significant (P<0.05) increase in the treatment containing prebiotic.Higher levels of the additives are suggested to be utilised for improving performance of the broilers reared under heat stress.

This study examined the effects of saturated and unsaturated fatty acids sources on meat quality (breast muscle fatty acid profile) and performance of broiler chickens. The experiment was carried out based on a completely randomized design with 225 chickens including three treatments and three replications for each treatment. The treatments were 1- diet with no oil 2- diet with soybean oil and 3- diet with sheep fat-tail oil. There were no significant differences among the treatment in terms of feed intake and feed conversion ratio for the whole period of the experiment. During weeks 3-5 there were significant (P<0.05) differences among the treatments for the body weight. Heart and liver weight were significantly (P<0.05) different among the treatment such that the broilers fed with treatment three had greater weight of heart and liver. Feeding soybean oil and sheep fat-tail oil could significantly (P<0.05) affect profile of fatty acids (myristic acid, oleic acid, vaccenic acid and alphalinoleic acid) found within muscle. Myristic and vaccenic acids content of breast muscle increased in the broilers fed with treatment three while they decreased as the treatment two was applied. It could be therefore concluded that using saturated and unsaturated sources may influence fatty acids profile of breast muscle in broilers.

In this study, production, reproduction, management and economic characteristics were measured from the records collected on six flocks (with 1,228 head of breeding ewes) during an annual cycle of production in nomadic system to determine traits performance as well as economic analysis of ewe rearing by the nomads of Chaharmahal and Bakhtiari province.Sensitivity of revenues to changes in production levels and economic variables were analysed. Variable expenses represented about 56.86 % of total costs. Fixed (43.14 %) and labour expenses (37 %) had the highest percentage of total costs, respectively. Feed and transporting costs accounted for 15.35 and 2.74 % of total costs were at the next important costs. Revenue from selling live animals accounted for about 98.7 % while fleece weight selling was only 1.3 % of the total revenues. Profit per ewe per year was estimated to be -373,319 Rials. Economic efficiency of the system (0.9) indicated thatthe revenue from the ewe rearing in nomadic system only covered 90 % of the rearing costs. If lambing rate achieves more than 150 % then economic efficiency will become more than 1 and as a consequence revenues willcoverthe costs of the system and profit isexpected to become positive. If price per kilogram lamb live weight increases from 100,000 to 115,000 Rials then production revenues will become equal to its costs. With respect to economic conditions of the country, number of weaned lambs per ewe in nomadic system is needed to be increased through management and breeding improvement if the job is profitably expected to go on.