نشریه پژوهش در تغذیه دام
سال دوم شماره 1 (بهار و تابستان 1394)

In order to determine of nutritive value of alfalfa in different cuts using nylon bags and gas production techniques, this study was carried out. Three wethers (49±2.6 kg) were used in in situ method. The gas production was measured at 2,4,6,8,12,16,24,36,48,72 and 96 h and ruminal DM and CP disappearances were measured 0,4,8,12,16,24,36,48,72 and 96 h. Dry matter degradability of mentioned cuts at 96h were 60.47,64.71 and 64.36%,respectively. Crude protein degradability of mentioned cuts were 60.48,63.08 and 58.07%,respectively. The gas production of mentioned cuts at 96 h were 322.54,295.21 and 300.32 ml/g DM. The coefficient of correlation between dry matter and gas production values for mentioned cuts obtained about 0.89,0.85 and 0.84 and this parameter for crude protein and gas production achieved 0.87,0.88 and 0.84,respectively. High correlation between in situ and gas production techniques indicated that digestibility values can be predicted from gas production data.

A study was conducted to evaluate the effect of adding essence and leaves of two species of Oregano (Mentaaquatica and Mentalongifolia) on gas production parameters, digestibility of dry matter and organic matter and microbial biomass production in two experiments separately. Collected two species of Oregano was taken essence by macro wave set at 110 0C and 450 nm for 45 minutes. The experimental treatments were: 1) control containing basal diet with forage: concentrate ratio 50:50 (without additive), 2) basal diet + Mentaaquatica lamiaceae essence, 3) basal diet+ Mentalongifolia lamiaceae essence, 4) basal diet+ Mentaaquatica lamiaceae leave and 5) basal diet+ Mentalongifolia lamiaceae leave. 8 macro liter of essence along 8 macro liter of ethanol in treatment 2 and 3 and 20 mg leaves of two kind of Oregano in treatment 4 and 5 were added to glass vial. The results showed that treatments containing essence and leaves had lower gas production than control treatment. Hence, treatment control and treatmenl) gas production, respectively. In second experiment, there were significantly differences aents that containing leaves of two kind of Oregano had lowest DM and OM digestibility compared with other treatments. Treatments containing essence had higher microbial biomass production and microbial biomass production efficiency. Generally, it can be concluded that essence of two kind of Oregano (even their leaves) has the potential to affect ruminal fermentation efficiency.

The aim of this study was to investigate the effect of different levels of eucalyptus essential oils on in vitro rumen fermentation parameters and methane production. Test gas production has done with using rumen fluid of fistuled sheep and with five replicates for each treatment in a completely randomized design.The parameters of studied was include 96-hour fermentation kinetics, fermentation parameters and protozoa population. The results showed eucalyptus essential oil were increased a (gas production from the immediately soluble fraction), b (gas production from the insoluble fraction) and potential extent of gas production (a+b). The methane produced was reduced (p=0.000) from 8 to 40 percent. Simultaneously with the increase in essential oil, nitrogen ammonia and total concentrations of fatty acids decreased (p<0/001), and partition factor and microbial biomass were increased. Level 5 ml of essential oils cased to improvement parameters of 24-hour gas, organic matter degradation and energy metabolism compared with other treatments. There is the correlation of 48-73 percent between reduction methane gas and protozoa population. The secondary metabolites essential oil reduced the total protozoa population and geneses of Entodinium, Ophryscolex, Isotricha, Dasitricha and Diplodinium. In general, the results of this experiment showed that eucalyptus oil has antimicrobial activity and were reduced methane emissions and improved the production of microbial protein.

In order to evaluate the different levels of a commercial plant-based growth promoter on performance, blood biochemical parameters, immune response and cecal bacterial population, 300 day-old Ross 308 (mixed sex) in 4 treatments, 5 replicates and 15 chicks in each replicate in a completely randomized design manner were employed. Experimental treatments were 1) control (basal diet, without any feed additive); 2) basal diet with 0.045% Flavomycin antibiotic growth promoter; 3) basal diet with 0.05% plant-based growth promoter and 4) basal diet with 0.1% plant-based growth promoter. Results showed that treatment having 0.1% plant-based growth promoter significantly (P<0.05) increased body weight and improved FCR in comparison with control group and also this treatment in decreased cholesterol content and increased HDL and immune response against ND, AI and IBD showed significantly (P<0.05) effective when compared with control and AGP fed groups. The groups fed antibiotic growth promoter have showed significant (P<0.05) decreased in cecal population of coliforms and E.coli than the control group, but for population of salmonella, only the treatment having 0.1% plant-based growth promoter has showed significant reduction (P<0.05).

An experiment was conducted to evaluate the effect of wheat and corn-based diets supplemented with multi-enzyme on growth performance and physiological characteristics of broilers. A total number of 375 one day old Ross-308 broiler chickens were allocated randomly to 3 treatments with 5 replicates at 2 rearing period (1 to 21 and 22 to 42 day) using a CRD statistical design. Treatments were included control, wheat and wheat+ enzyme. Traits were growth performance, carcass traits, serum metabolites and mineral concentrations. According to the results, the effect of wheat with and without enzyme on experimental traits at entire of the period was significant (P<0.01).At the whole of rearing period the maximum and minimum feed intake, gain and adversely the minimum and maximum of FCR observed in control (corn) and wheat groups respectively (P<0.01).The control and wheat+ enzyme groups had the highest and wheat group had the lowest concentration of serum minerals respectively (P<0.01). The maximum and minimum serum concentration of glucose, TG and cholesterol were belonged to control and wheat groups respectively (P<0.01). Enzyme supplementation of wheat diet resulted in improvement of growth and carcass traits and increased the concentration of serum metabolites and minerals (P<0.01).

Dry matter digestibility (DMD) of forages is very important in ruminant nutrition. Because in vivo and in vitro procedures to determine dry matter digestibility are time-consuming and expensive, providing an easy and fast technique would be of interest. Modeling approach is a novel procedure for predicting an output from some predictors in a system. In this study, DMD of several tropical forages were predicted from chemical analyses including crude protein (CP), crude fiber (CF), ash and acid detergent fiber (ADF). Five tropical forages were harvested in 10 replicates and each sample was analyzed for CP, CF, ash and ADF as inputs and DMD as output. A total of 50 data lines were divided into training (35 data lines) and testing (15 data lines) subsets. Three modeling approaches including artificial neural network (ANN), principal component analysis (PCA), and partial least squares (PLS) were implemented; and performance of each model was evaluated using coefficient of determination (R2), mean square error (MSE), mean absolute deviation (MAD), mean absolute percentage error (MAPE), and bias. The results showed that ANN-based model outperformed the classical regression methods. The ANN-based model with the highest R2 (0.95) and lowest residual distribution (MSE = 0.871, MAD = 0.772, and MAPE = 1.44) gave the best predictions for DMD.