مجله پژوهش در نشخوار کنندگان
سال دهم شماره 1 (بهار 1401)

Provision of food in a fattening period includes about 65 to 70% of the costs related to livestock breeding and maintenance. The most important issue in preparing the ration is choosing raw materials with high availability, cheap price and nutritional value to meet the recommended nutritional needs of each type of livestock. corn steep liquor is one of the industrial wastes, which is produced during the wet milling process of corn kernels for the extraction of corn starch and oil. Processing is one of the ways to change and improve the nutritional value of grains, especially starch and protein. Among the reasons for using corn steep liquor, we can mention the high nutritional value of corn steep liquor (high protein content), the level of corn steep liquor production in the country and the cheap price of this by-product.

The aim of this experiment was to evaluate the effect of aldehyde-treated corn steep liquor on soybean meal on growth performance, ruminal parameters and purine derivatives of fattening lambs. 37% formalin at a concentration of 3.5% was used to process corn steep liquor. Twenty-five male Lori Bakhtiari lambs with an average weight of 26±3 kg and an age of about 3 months were allocated in a 105 day period (15 days of adaptation and 90 days of the main period) in a completely randomized design with 5 experimental treatments and 5 replications. Experimental treatments included soybean meal with different levels of corn steep liquor processed with formaldehyde (0, 25, 50, 75 and 100%) replaced in the diet.

The highest body weight, daily feed intake and daily weight gain were related to lambs fed with 100% Formaldehyde-processed corn steep liquor and the lowest feed intake and daily daily weight gain. It was related to lambs fed with control treatment (P<0.05). The feed conversion ratio improved but did not increase with increasing the level of formaldehyde-treated corn steep liquor. With increasing the amount of formaldehyde-treated corn steep liquor in the diet, the pH of the lambs rumen decreased significantly (P<0.05). In all experimental diets, ruminal fluid ammonia concentration was reported in the optimal range (8.5 to more than 30 mg/dL). Total concentrations of volatile fatty acids, acetate, propionate and butyrate density, acetate to propionate ratio in ruminal fluid of experimental animals fed a diet containing formaldehyde-treated corn steep liquor were not affected by the experimental diets. However, the ruminal density of valerate and isovalerate decreased significantly with increasing the salinity of formaldehyde-processed corn steep liquor (P<0.05). Excretion of each purine derivative (allantoin, uric acid, xanthine + hypoxanthine) and total excretion and absorption of purine derivatives from urine and the amount of microbial protein produced in the rumen were affected by experimental diets and the observed difference was significant. (The control treatment showed the highest and the 100% level treatment of formaldehyde processed corn steep liquor showed the lowest) (P<0.05). Urinary excretion of nitrogen decreased with increasing fat content of formaldehyde-treated corn steep liquor in the diet.

The results of the present experiment showed that the use of formaldehyde-processed corn steep liquor in lambs diet, body weight, daily dry matter intake and daily weight gain, increase and amount of ammonia, pH, valerate and isovalerate fatty acids and microbial protein production Reduces rumen in lambs and reduces the breakdown of protein in the rumen, and the feed protein is broken down in the small intestine and the use of formaldehyde-treated corn steep liquor with soybean meal has no adverse effect on livestock performance.

Imbalance of between rumen degradable protein (RDP) and microbial protein (MP) production decrease animal performance and increase environmental pollution. Therefore to meet the requirements for microbial protein without excessive N, rations must also be balanced for RUP and RDP. Sunflower meal (SFM) is a protein feedstuff for ruminants. However, its use in ruminant nutrition is often limited by high protein degradability in the rumen. Irradiation is new method that is considered in protein feedstuffs processing. The aim of this study was to investigate the effect of irradiation on rumen degradation kinetics and in vitro digestibility of SFM.

SFM samples were irradiated with the use of the gamma ray (GR) in doses of 20 and 40 KGy and microwave (MV) at 800 W for 3 and 5 minutes. Irradiations of samples were done in Radiation Applications Research School, Nuclear Science and Technology Research Institute. Chemical composition of unirradiated and irradiated SFM were determined. Degradability parameters of the samples were measured by nylon bag technique using three rumen fistulated Dashtyari cattle for 0, 2, 4, 8, 16, 24 and 48 hours. The two-step digestion technique was used to determine digestibility of SFM. Statistical analysis of data was performed using SAS software.

GR irradiation decreased DM of SFM. Irradiation of SFM caused a reduction in EE, NDF, ADF and Ash and increased CP compared to unirradiated SFM. GR irradiation decreased wash out fraction degradation, rate constant of degradation of b fraction and ERD and increased potentially degradable fraction of SFM. MV irradiation for 5 minutes increased washout fraction of CP and decreased potentially degradable fraction (P<0.05). Treatment of SFM by MV for 5 minutes caused a reduction in potential degradability of CP (P<0.01). Processing of SFM with MV for 3 minutes decreased ERD of CP at rumen outflow rate of 0.02h-1(P<0.05). GR irradiation decreased RDP and increased RUP and metabolizable protein (MP) (P<0.01). Irradiation of SFM with GR increased ERD of CP at rumen outflow rate of 0.05h-1 and 0.08h-1 (P<0.01). Irradiation of SFM with MV increased RDP(P<0.01) and increased ERD and MP at rumen outflow rate of 0.02h-1 (P<0.01). MV irradiation for 3 minutes at rumen outflow rate of 0.02h-1and 0.05h-1increased RUP(P<0.05). The coefficient of crude protein convert in to RDP and RUP in GR- irradiated SFM was decreased and increased respectively (P<0.01). MV irradiation for 3 minutes at rumen outflow rate of 0.02h-1 coefficient of crude protein convert in to RDP and RUP decreased and increased respectively (P<0.05). In vitro digestibility of SFM was unaffected by irradiation (P>0.05).

The experiment results indicated that, irradiation of SFM with GR had better effect on increasing of RUP and improving of quality of SFM.

Luteinizing hormone (LH) is one of the most important reproductive hormones that is secreted by the anterior pituitary gland and plays a key role in regulating the estrous cycle, maturation of ovarian follicles, ovulation, corpus luteum formation, corpus luteum development and maintenance. The LH message is transmitted through by binding it to its extracellular receptors, so that after binding to its own receptor (LHR), LH activates the intracellular cascade chain by activating the secondary messenger cAMP, and ultimately the expression of specific proteins and enzymes. Therefore, the interaction of luteinizing hormone (LH) with its specific receptor (LHR) is one of the key steps in the path of follicular maturation and ovulation. Polymorphisms and LHR splicing are among the genetic changes that can affect LH function and consequent reproductive efficiency.The aim of this study was to compare the tertiary structure of different LHR polymorphisms and their binding affinity to LH in dairy cows.

For this purpose, LHR amino acid sequences were obtained from Gene bank. Firstly, Polymorphisms were identified by alignment analysis. Their related third structures were predicted by homology modeling technique using Modeller software. The created structures were observed and evaluated using PyMol 2.5.1 graphics software and Ramachandran plot. Also, different physico-chemical parameters of the modeled proteins such as isoelectric point, molecular weight, and number of negative and positive sequences and Grand Average of hydropathicity (GRAVY) were calculated using ProtParam tool in Expasy database. Then, the affinity of LH to each of the LHR polymorphism was evaluated using molecular docking technique based on binding energy and spatial position indices.

Based on the results, only two polymorphisms (LHR1 and LHR2) were identified among the studied sequences. The predicted models for the two polymorphisms have a good quality and there was no difference in structural and physicochemical parameters between them. Docking results showed that, despite the difference in total binding energy between the two polymorphisms, this difference could not be attributed to amino acid substitution and this difference is probably related to an orientation of the LH relative to the LHR1 and LHR2. Most of the amino acids that were involved in hydrogen bonding were similar in both the LH-LHR1 and LH-LHR2 complexes.

In general, the results of this study can be used to the relationship between LHR polymorphism and its physiological activity.

Investigation of fermentation parameters by gas production method is one of the common methods for evaluating feeds and can be a reflection of the fermentation pattern in the rumen. The gas production method in a relatively short time can evaluate the fermentation process of feeds and a large number of samples, and also used to determine the quantity and quality of value and digestion rate of a feed. In recent years, the flaxseed and its oil, due to high concentration of α-linolenic acid extremely considered and used as a fat supplementation in diets of ruminant, but one of the most important concerns in the nutrition of oilseeds is the negative effects of their unsaturated fatty acids on ruminal fermentation. The aim of this study was to evaluate the digestibility, gas and microbial protein production of diets with different forms of flaxseed (whole, grounded and extruded) and the high (40%) and low (20%) levels of rumen undegradable protein (RUP).

Two hundred mg of each feed sample was incubated with ruminal fluid with buffer and gas production was measured at 2, 4, 6, 8, 10, 12, 24, 36, 48, 72, 96 and 120 h. The experimental diets were: 1) diet no flaxseed + 20% RUP; 2) diet no flaxseed + 40% RUP; 3) diet containing 10% whole flaxseed + 20% RUP; 4)diet containing 10% whole flaxseed + 40% RUP; 5) diet containing10% grounded flaxseed + 20% RUP; 6) diet containing10% grounded flaxseed + 40% RUP; 7) diet containing10% extruded flaxseed + 20% RUP, and 8)diet containing 10% extruded flaxseed + 40% RUP.

The results showed that the amount of gas production during 96 hours incubation was higher with control diets compared to other diets (255.8 vs 217.8, 198.1 and 200.4 ml/g DM, P=0.001) and also at 20% RUP level (255.5 vs 210.1 ml/g DM, P=0.049). True digestibility of control diets (684 vs 568, 619 and 538 mg/g DM) and NH3-Nof diets containing grounded flaxseed compared to other diets (1.12 vs 0.41, 0.49 and 0.21 mg), was higher (P>0.05), but microbial nitrogen production by diets containing grounded flaxseed compared to other diets (2.72 vs 3.29, 3.36 and 3.45 mg), was lower (P>0.01). The disappeared DM (161.6 vs 149.9 mg), neutral detergent insoluble nitrogen (1.63 vs 1.35 mg) and NH3-N (0.76 vs 0.35 mg) with 40% RUP, and microbial nitrogen production (3.48 vs 2.93 mg) in 20%RUP (P>0.05), was higher.

Since one of the main objectives of the present experiment was to examine the production of microbial protein in experimental diets, diets containing whole and extruded flaxseed despite their low digestibility, but showed higher microbial protein production. On the other hand, 20% RUP level also showed the highest amount of gas and microbial protein production. So, it seems from an economic point of view as well as the performance of the diets, using a diet containing 10% extruded flaxseed along with 20% RUP can be beneficial and effective.

As newborn farm animals are almost lacking adequate immunoglobulins to tolerate against environmental pathogens, feeding colostrum is a pivotal action in first days of their life and finding approaches to enhance immunoglobulins absorption into neonates' blood is highly interested. Therefore, the goal of the study was to investigate the effect of controlled-heating of colostrum on immunoglobulins' absorption and some blood and immunity parameters.

Forty neonatal male Zel lambs (4.49±1.21) were divided into two groups; one group was fed with three equal meals of raw colostrum as 15% of BW during the first 36 hours of age and the other group was fed with the equal amount of heat-treated colostrum. For this purpose, a pool of colostrum was first collected from the previously lambed ewes of the herd and gently mixed. Then, half of collected colostrum was heated indirectly in water bath (bain-marie) at 63 °C for 30 minutes. Both raw and heated colostrums were stored and frozen in 2.5kg nylon packs. Immediately after birth, lambs were ear-tagged and weighed and then first blood samples were taken. The assigned colostrums then were fed to lambs by bottles. After the end of feeding colostrum, lambs were fed with milk and starter feed until d 35 of age. Fasted blood samples were taken immediately after birth (day 0) and days 5, 20 and 35 of age and the sera were frozen until serological assay of total protein, albumin and immunoglobulin G. Apparent efficiency of absorption of immunoglobulins was calculated by the respective equation. The data were statistically analyzed as a repeated measures design with a completely randomized arrangement including two treatments and 10 replicates.

The results showed that feeding the heat-treated colostrum had significant effects on serum immunoglobulins, globulins and albumin concentrations of lambs (p<0.05), where feeding the controlled-heated colostrum caused about 39.5 and 38.1% significant increases in serum immunoglobulins levels of lambs in days 5 and 15, respectively. Serum globulins level was significantly greater in lambs fed heat-treated colostrum than other group. In contrast, serum albumins level was significantly greater in lambs fed raw colostrum in days 5, 20 and 35 (p<0.05) as compared the other group. Heating the colostrum caused a marked increase (p=0.0001) in apparent efficiency of absorption of consumed colostral immunoglobulins into lambs blood (43.04 vs. 23.05%). No significant effects were observed in serum total protein concentrations of lambs in both groups.

In general, the results of the study showed that the controlled, in-direct heating of ewes' colostrum at 63 °C for 30 minutes causes an increase in immunoglobulins absorption into lambs' blood.

Consumable fats in ruminant products are the main source of various conjugated linoleic acid isomers with a wide range of positive effects on human health. Various genetic factors such as race type are considered as one of the effective factors on the effect of different environmental factors on plasma levels, growth, energy distribution between different tissues of the body and the pattern of fatty acids and the chemical composition of the carcass. There are several studies on dairy cows on the role of various dietary factors including fatty acids in their effect on performance and energy metabolism. However, there is not much research on other ruminant species, including Iranian sheep, and comparisons between tail and tail tails in response to different dietary energy sources. Therefore, this study was performed to evaluate the effect of high-energy diets rich in carbohydrates or protected fat sources on performance, expression of TNF-α gene and some blood metabolite in male lambs of Taleshi and Zel.

This study was performed in an experimental period of 116 days (14 days of habituation and 102 days of sampling). At the end of the habituation period before breakfast, the animals were weighed and kept individually (6 lambs of Taleshi breed and 6 lambs of Zel breed for each treatment). Control diet (fat-free diet), diet containing 4% saturated fat supplement rich in stearic acid and diet containing 4% unsaturated fat supplement Protected apparent digestibility of dry matter, organic matter, fat Crude, crude protein and insoluble fibers in neutral detergent and insoluble fibers in acidic detergent were measured by the recommended method. The amount of dry matter consumed was measured by taking into account the amount of dry matter remaining in the manger (post-manger) and the amount of dry matter in the diet.

The highest amount of feed consumed at the end of the period belonged to Zell and Talshi periods consuming feed containing stearic saturated fatty acid. The digestibility of dry matter, organic matter, NDF and ADF was affected by the effect of fat, but the effect of race and the interaction of race and type of fat did not affect their digestibility. The interaction effect of race and fat on the digestibility of crude protein and ether extract was significant (p <0.05). Crude protein digestibility was not affected by fat type. The highest crude protein digestibility was observed in the treatment of protected unsaturated fat of Taleshi breed and the lowest amount was observed in the treatment of protected unsaturated fat of Zell. The highest digestibility of ether extract was observed in the treatment of Taleshi protected unsaturated fat (p <0.05). The expression of TNF-α gene was higher in the subcutaneous fat of the protected lambs of the unsaturated treatment (p <0.05). Also, TNF-α gene expression was higher in tail fat and tail fat samples of talus lambs with protective unsaturated treatment and less stearic acid treatment in Zell lambs than other treatments (p <0.05).

In general, it can be concluded that the addition of fat supplement in the diet of Taleshi and Zel lambs improves blood parameters and increases the immune system according to the expression of the tumor necrosis factor alpha gene (TNF-α) and thus improves Due to the fact that the best results were obtained in the treatment of protected unsaturated fat supplement, the use of this fat supplement at the level of 4% in the feeding of fattening lambs of Taleshi and Zel breeds is recommended.

Mature milk is the most complete feed for weaning calf, but use of liquid feeds such as milk replacers, transition milk (TM) and waste milk results in maximum benefit due to their lower cost. This experiment was aimed to study the effect of extended transition milk feeding on nutrients intake, feeding behavior and rumination pattern of f Holstein dairy calves.

Calves were enrolled in the study in chronological order according to their birth date. During 21 consecutive days, calves were enrolled in the individual pens (4 calves daily; one calf per treatment per day) progressively as born. A total of 84 healthy newborn female Holstein calves (3days of age; BW = 35.8 ± 0.56 kg) were randomly allocated to four experimental groups. Four groups included:1- TM0, daily pooled 6 l pasteurized waste milk , 2- TM0.5, a daily mixture of 5.5 l pooled pasteurized waste milk with 0.5 l pooled pasteurized TM, 3- TM1, a daily mixture of pooled pasteurized waste milk with 1 l pooled pasteurized TM, and 4- TM2, a daily mixture of 4 l pooled pasteurized waste milk with 2 l pooled pasteurized TM. Treatments were applied for a 21-day period and all calves were then fed individually with 6 l/day pooled pasteurized waste milk till day 60. Individual daily feed intake, particle size intake of starter diet, sorting index and feeding behavior were determined.

The results showed that the interaction of period and level of TM and level of MT had no effect on starter nutrients intake. However, intake of dry matter, crude protein, neutral detergent fiber, non -fibrous carbohydrates and ether extract were higher in post weaning period that pre weaning period for all of experimental groups. Feed sorting index data showed that calves selected for feed particle with 2.36 mm and calved fed TM0 had the highest sorting value for particle size 2.36 mm. Particle size intake of starter diet nutrients were not different among experimental groups. The interaction of period and level of TM had no significant effect on feeding behavior and meal pattern. However, meal interval was affected by the interaction of period and level of TM, so that calves received 1 L TM had the greatest meal interval. Furthermore, calves received 2 L TM had the highest eating time.

The results showed that mature milk could be replaced by TM in dairy calf nutrition without any negative effect on dry matter intake and feeding behavior.

The bovine rumen is the suitable growth medium to many of the bacteria responsible for converting food into energy. In recent years, many rumen microbes have been identified and isolated using 16sRNA gene sequencing. Some microbes are suggested as food additives to promote the growth and production of animals. The use of probiotics as feed additive has been induced by stimulating the positive effects on the host by creating a favorable balance of intestinal microflora. Therefore, is study aimed to isolate, identify and select lactic acid bacteria to produce probiotics from the rumen and feces of Sistani cows.

In this experiment, samples were taken from the rumen of 12 and the feces of 4 Sistani cows in the industrial slaughterhouse of Zabol city. The samples were transferred to test tubes containing liquid MRS culture medium and incubated at 39 ° C for 48 hours. After growing from the mentioned medium, the plates containing MRS agar were linearly cultured and the plates were incubated in aerobic conditions at 39 ° C for 48 hours. The emerged colonies were examined for growth characteristics and morphology as well as purity. Gram-positive, spore-free, spherical negative catalase, and rod-shaped bacteria that did not produce beta hemolysis were tested for antimicrobial, acid, bile salt, and antibiotic susceptibility testing.

Of the initial 158 isolates of lactic acid bacteria, 84 isolates were tested for antimicrobial activity against four species of Salmonella and one species of E. coli. Then the isolates obtained from the antimicrobial test were examined for pH resistance test. Thirteen samples selected from this experiment were studied for bile resistance test, of which five isolates were examined for antibiotic susceptibility testing and entered the final stage for genetic and molecular testing.There were only two isolates that were obtained by molecular testing and after sequencing and using NCBI software had a high genetic affinity with two bacteria Streptoccos infantarius (isolate A) and Entrococcos faecium isolate B. These two isolates were observed as potential probiotics in Sistani cows.

The general results of the study showed that isolates A and B have suitable properties for the use of probiotics. . These characteristics are high survival rate at low pH and 3% bile concentration and inhibition of pathogenic bacteria such as E. coli and Salmonella, as well as antibiotic resistance. Therefore, isolates A and B will later be used as probiotics the ruminants feed.