مجله تحقیقات دام و طیور
سال دوم شماره 3 (1392)

This experiment was conducted todetermine chemical composition and degradability parameters of different wheat bran in feed-producing factories in Birjand (Southern Khorasan province) and Iranshahr (Sistan and Baluchistan province). Samples were monthlytaken from four factories.Total duration of sampling was six months. Samples of wheat bran were separated based on particle size and theirs chemical composition were measured. The measured parameters were: crude protein,neutral detergent fiber and weightpercentage. Degradability parameters of wheat bran samples were determined bygas production. The results showed concentration of CP, NDF and weight percentage were not different between different factories, exact amount of NDF in two factories on different months. The highest amount of NDF was for particle size greater than 1.18 mm and the lowest amount of NDF was for particle size lower than 6.25 mm. The highest of weight percentage was for particle size within the range of 0.5 – 1.8 mm. Produced gas (in 24 h) was significant between treatments. The highest amount of gas after 24h incubation was for particle size lower than 0.2 mm and the lowest was for particle size greater than 1.18 mm. Gas produced from insoluble fraction was significantly higher for the particle size lower than 0.25 mm in all factories decreasing of particle size, b coefficientincreased in all factories.

This experiment was conducted to evaluate the effects of different levels of vitamin premix (VP) at the last three weeks of rearing period (22 to 42 days) on performance, immune system status, toe bone characteristics and oxidation in thigh of broilers with four hundred male birds (Ross-308) in a completely randomized design with ten treatments and four replicates. The dietary treatments were: T1 without VP during 22 to 42, treatments 2, 3 and 4 with 33.33% VP, treatments 5, 6 and 7 with 66.66% VP and treatments 8, 9 and 10 with 100% VP that treatments 2, 5 and 8 only from 22 to 28, treatments 3, 6 and 9 only from 22 to 35 and treatments 4, 7 and 10 only from 22 to 42 days of age received diets containing VP. The results indicated that reduction and withdrawal vitamin premix from 22 to 42 days of age did not impair performance and toe bone characteristics. The results of thigh oxidation at three month after slaughter, did not show significant different among treatments, but after 6 month of freezing observed significant different among treatments with 66.66, 100% VP and T1 without VP (P< 0.05). The results of this study demonstrated that it is possible to reduce VP (33.33%) in the last three weeks of rearing period without any negative effects on performance, bone characteristics and meat quality.

This study was conducted to investigate the effect of feeding Ferula Ovina as an alternative to alfalfa hay, on digestibility and blood parametersin Kermani sheep. The design of experiment was 4×4 in four periods of 21-day which include 16 days of adaptation and five days for sampling.Experimental diets were as 1-Control(without Ferula Ovina); 2- diet containing %10 Ferula Ovina; 3- diet containing %20, Ferula Ovina and 4- diet containing 30% Ferula Ovina (completely replaced alfalfa hay).Chemical composition and metabolizable energy of Ferula Ovinaand alfalfa were determined.The result showed that crude protein (CP) and crude fiber were lower but EE, metabolizable energy and ash were higher in Ferula Ovinathan alfalfa. Feeding Ferula Ovina significantlyreduced dry matter intake (P<0.05). However, there was no effect on organic matterdigestibility. Dry matter (DM) and CP digestibilities were changed cubically and quadratic ally, respectively.However, NDFandADFdigestibility were changed linearly. Replacing alfalfa by 30% Ferula Ovina caused an increase following by a decrease in cholesterol and blood creatinine (P<0.05), but no effect onglucose, triglycerides andureanitrogen of blood were achieved.In conclusion,replacing alfalfa by10% Ferula Ovinahad no negative effecton sheepperformance anddue tolessreplacement cost thanhaycrop,the efficiencyoflivestock husbandry will be improved.

This experiment was designed to evaluate the effect of wet feeding on performance, carcass characteristics and some blood biochemical parameters of broilers in corn-soybean meal based diets under heat stressed condition. 160 one day old mail broilerchicks(Ross 308) with equal weight average in a completely randomized design. The experimental units were divided into four treatments,four replications per each treatment(ten chicks into each replication). Chicks up to 7 day fed with diet based on corn-soybean meal in the normal form and after 7 day, experimental treatments including 4 level of moisture (, 50, 100 and 150 percent) were given to them. Foodpreparationwascarried outin several times and was given to broilers.Broilers at 4 weeks were grown with the recommended temperature guide of Ross strain and in the last 2 weeks were grown for eight hours from 9 am to 5 pm under heat stressed conditions at a temperature of 33 ± 1 ° centigrade. At the age 42 d,two chicks from each replication were selected and slaughtered. The results showed that experimental treatments at the end of the growth period were significantly different in feed intake and weight gain and feed conversion ratio (P<0.05). Regarding characters at the end of experimental period, control treatment showed better performance.There were no significant differences between experimental treatments in carcass characteristics and blood biochemical parameters.

Leptin, a 16-kDa protein secreted from white adipocytes, has been implicated in the regulation of feed intake, energy expenditure, and whole-body energy balance, reproductive, immunity, growth and obesity gene product (obese) coded by a gene called ob gene. The present study has been designed to determine polymorphism in exon and intron 2 region of leptin gene in Mahabadi goat using PCR SSCP. Blood samples were collected from150 Mahabadi goat belong to the Department of Animal Science, University of Tehran (Karaj). DNA was extracted using salting out method. DNA quality and quantitative was determined using spectrophotometer and 1% agarose gel. A fragment 271bp of exon and intron 2 region of leptin gene was amplified using the polymerase chain reaction. SSCP technique was used to analyze polymorphism in this segment of DNA. PCR products were run in 12% polyacrylamide gel electrophoresis for 2 h. Gels were stained with silver nitrate. Developing pattern showed the same pattern in all animals and was monomorph. The results of this research showed seven mutations for this locus that the Mahabadi goats breed for these mutations are monomorph and these mutations ordinary was reported in other breeds of goats.

This experiment was conducted to evaluate the effect of choline chloride supplementation in diets containing different levels of fat on the performance, carcass composition and meat quality of broiler chickens underheat stress condition. Broiler chicks fed with one of six treatments contained 2 levels of fat (zero and 5 percent) and 3 levels of choline chloride (zero, 0.1 and 0.2 percent). Birds were exposeddaily 4 hours to 35
c from 22 up to 42 days of age. Broiler chicks were fed diets containing 5 percent fat had significantly higher weight gain during starter and whole period of experiment. The supplementation of choline chloride to diets led to significant increase of feed intake and weight gain during whole period of experiment. The utilization of diets containing 5 percent fat led to increase of breast and abdominal fat weight. The supplementation of choline chloride led to significant increase of carcass, breast and tight weight. The index of a* value in broiler chicks fed diet supplemented with 0.1 percent choline chloride significantly decreased rather than those birds received no choline chloride, but there was no significant difference for L* and b* indexes. The utilization of fat at 5 percent led to significant increase of malondialdehyde value. Broiler chicks received diets without or 0.2 percent choline chloride significantly had higher water holding capacity than those birds received diet containing 0.1 percent choline chloride. The supplementation of choline chloride to diets had no significant effect on meat pH values.

This research aimed to estimate heritability, phenotypic and genetic trends for the trait of energy-corrected test day milk of Iranian first-parity Holstein cows. A total of 774,013 test day recordso 88,456 firstparitycows(three times milking a day) calvedduring 1997-2009 in 165 herds (six provinces) was used
Genetic analysis was carried out by a fixed regression test day model in which the effects of province, herd, calving year, production month, cow genotype (grade or pure Holstein), sperm type, production age, Ali and Schaeffer’s polynomial function, as well as additive genetic and permanent environmental random effects of the cows were included. Heritability and repeatability of the trait were found to be 0.127 and 0.421, respectively. Statistically significant phenotypic (0.414 kg) and genetic (0.076 kg) annual trends were found (P<0.0001). There was a significant difference (P<0.0001) between mean breeding value for the progeny of local (-0.031 kg) and exotic bulls (0.3747 kg). This research revealed that genetic trend for 305-d energy corrected milk trait was found to be 0.26% of the phenotypic mean indicating that selection pressure has not been too effective over the past years.

The aim of this study was to determine the best predictive model for the accurate description of the average daily egg production being produced by the layers during the productive period. A total number of 81,565 daily egg records (1999-2000) were used. In the current study, Modified Gamma, Compartmental, Algebraic, Modified Compartmental, Logistic-Curvilinear, Narushin and Takma 2 (NT2) and Lokhorst functions were fitted using NLIN procedure of SAS software. Mean error sum of squares (MSE), adjusted coefficient of determination (Adj-R2), Akaike information criterion (AIC) and Durbin-Watson (DW) statistics were used for evaluation of the functions. The results revealed that Logistic-Curvilinear function was the most preferable one because its Adj-R2 value was the highest while it’s MSE and AIC values were lower than for the remaining functions. Assessing the goodness of fit of the used functions precisely, however, it was concluded that almost all of the functions are accurate enough in describing the average daily egg production curve. In such conditions, other features of functions should be considered and it seems that the simpler the function is mathematically the more desirable it is for the researcher or farm manager.