جستجوی مقالات مرتبط با کلیدواژه « season » در نشریات گروه « کشاورزی »

Honey bees are small insects with many useful products. Venom is one of these products with therapeutic benefits and high commercial value. Many factors affect the bee venom and its main components, namely Melittin, Apamine and Phospholipase A2. This study investigates the effect of seasonal and geographical location on the venom composition in 8 cities, during three seasons of spring, summer and autumn, in a completely randomized design with 4 replications(hives). Analysis of venom samples from the target areas in different seasons by HPLC showed that the mentioned components, other than apamine (correlation=0.339), had no correlation with temperature. The mean amount of Protein, Melittin and Phospholipase A2 of the treatments did not differ significantly during the 3 seasons (p>0.05). The mean percentage of melittin (63.15 %) and phospholipase A2 (8.19 %) in spring; apamine (4.03 %) and protein (48.89 µg/100mg) were maximum in summer. The highest amount of Protein and Apamin in the venom was related to karaj (50.28% and 4.33% respectively), the highest amount of Melittin in khoramabad city and the highest Phospholipase A2 was in birjand city. The effects of season have on venom components through temperature can be in addition to the direct effect on honey bees and venom production glands, through the effect on vegetation of area or the presence of seasonal changes in the venom components in addition to the effect of geographical location, a reflection of the difference in vegetation.

The aim of this study was to evaluate the effect of seasonal variations on some of the hematological and serum biochemical parameters on some 2-3 years' old great sturgeon cultured in brackish water pens for yearlong from autumn 2015 to summer 2016. At different seasons, after anesthetizing the fish with clove extract, blood sampling was done, from a total of 15 great sturgeon specimens were apparentlyat healthy condition in 3 separately pen's. Blood samples was analyzed by the routine method used in fish hematology. There were no significant differences in amount of the cortisol, mean corpuscular volume (MCV) and activity of Alanine aminotransferase (ALT) in the different seasons (p>0.05). The maximum WBCs, Activity of aspartate aminotransferase (AST) and alkaline phosphatase (ALP) were observed in summer (p<0.05).  </span>The maximum RBCs, hematocrit concentration, total serum protein were observed in spring (p<0.05). The maximum hemoglobin concentration, the mean corpuscular hemoglobin (MCH) and the mean corpuscular hemoglobin concentration (MCHC) were observed in autumn (p<0.05). The maximum level of glucose was observed in winter (p<0.05). In conclusion, the result of this study showed that the changes of temperature as a result of season transition may have an important role in the blood parameters of H. huso</em>, resulting that, at the same ecological conditions, any changes in environment temperature, in the water, affecting the blood cells indices in Beluga.</span>

Junipers of Iran are indigenous, beautiful and resistant plants with various usages in horticulture and Forestry. These plants are found in natural resources places naturally; unfortunately they are getting extinct because of Annihilation of natural habitats and also atmospheric changes. So, researches on propagation and protection of them are so important. One of the effective materials on asexual propagation of this plant, cutting, that is really efficient is coconut juice. To introduce natural materials instead chemical hormones for rooting Maymars cuttings and also to select the best season and substrate, recent experiment was done with 5 levels of coconut juice (0, 25%, 50%, 75% & 100%) in 4 substrates contained, perlite, perlite-cocopite (1:1), Pumice and rooting substrate (combination of sand, perlite, cocopeat, vermicompost and peat moss) and 4 seasons of year on Maymars cuttings with length 15 cm. The experiment was done in 3 replications, and each one contained 9 cuttings. The aim of the experiment was finding the best season, substrate and natural treatment to propagate this plant. At the end of each season, rooting percentage, root length, root numbers, fresh and dry weight of roots were registered in each substrate and treatment. The result showed that the best season for rooting the Maymars cuttings is spring. The best rooting between all treatments was related to level 25% coconut juice in perlit-cocopeat (1:1) substrate with more than 30% rooting. In winter no rooting was seen in none of substrates and treatments. Highest amount of roots was seen in fall and also perlit-cocopeat (1:1) substrate. Maximum root length was seen in spring and minimum of that was seen in summer. Also maximum root length was seen in pumice substrate. Highest amount of root fresh and dry weight was resulted in spring. And also highest amount of root fresh weight was found in perlite substrate and there was no different in amount of root dry weight in all substrates equally. Generally, it can be concluded that coconut juice causes rooting percentage increase in cuttings, because of containing auxin. And it is advised to use them instead chemical materials. To propagate Maymars junipers via cutting it is found that spring is the best season to propagate this species and other seasons are not proper and acceptable to propagate this plant. Generally, in can be concluded that coconut juice increases the rooting of Maymars cuttings as containing natural auxin and the best level is 25%. The best rooting between all treatments was related to level 25% coconut juice in perlit-cocopeat (1:1) substrate with more than 30% rooting.

Decreased hatchability and increased embryonic mortality in hatchery are economically important. The purpose of this study was to investigate the effects of month, season, flock age and egg size (weight) on hatchability and embryonic mortality during incubation period. The data were collected by frequent reference to the hatchery, and the total of hatched eggs from broiler breeder flocks was recorded between March 2016 to September 2016. Moreover, unhatched eggs were thoroughly investigated. In this survey, the third method (unhatched eggs breakout in the end of incubation) was used for different stages of embryonic mortality. Of the total number of 2372604 hatched eggs, 75.73% eggs and 24.27% eggs were hatched and unhatched (embryonic mortality), respectively. The effect of months and seasons spring or summer was significant (p<0.05) on the average percentage of hatchability and embryonic mortality, so that September and summer had the lowest hatch and the highest embryonic mortality. Decreased hatchability and increased embryonic mortality were observed with increasing of the flock age and the egg size (p<0.05). The highest rate of embryonic mortality was in infertility and stage VI. The results of this study showed that month, season, flock age and egg size (weight) have an effect on hatchability and embryonic mortality.

Land use change in the northern part of Iran has changed the quality of soil. The aim of this study was to investigate the impacts of different kinds of land use/cover, i.e. virgin natural forest, degraded natural forest, alder plantation, sequoia plantation, improved fallow and home garden areas on soil biological characters in plain area of northern Iran. For this, 30 soil samples were taken from a depth of 0-10cm in the studied land use/covers. Density and biomass of earthworm ecological groups, soil nematodes density and the rate of carbon dioxide emission were evaluated from top soil during 4 seasons. Also, some physicochemical properties were measured at the laboratory. The maximum of earthworms density, (3 n m-2), earthworms biomass (38.76 mg m-2), nematodes density (457 in 100 g soil), and the emission of carbon dioxide (0.47 mg CO2-C gsoil−1 day−1) belonged to Alder land cover. In all the studied land use, every three groups of earthworms and nematodes had jointly the highest activity in the spring and autumn, while the highest amount of carbon dioxide emissions was recorded in the summer. PCA showed the highest positive effect the soil pH, nitrogen and nutrients with biological properties. As a result, it can be concluded that plantation with Alder species is a good way to improve biological indicators and maintain soil quality in degraded areas of forests in the northern Iran with similar condition.

Mycorrhizal fungi, as a part of soil organisms, are mutualism for plant species that lead to an increase in soil fertility by enzymes secretion itself and stimulating the secretion of plant enzymes. The present study was carried out to investigate the potential and identification of arbuscular mycorrhiza fungi associated with Cerasus mahaleb and enzymes activity of acid and alkaline phosphatase, urease and dehydrogenase. For this purpose, roots of five trees of Cerasus mahaleb and their rhizosphere were sampled in ChaharTagh-e-Ardal habitat located in ChaharMahal va Bakhtiari Province. Arbuscular mycorrhizal fungi were isolated by wet sieve and identified using morphological characteristics. After soil extraction and carrying out biochemical reactions, soil enzymes activities were measured by spectrophotometer. In this study, six species of arbuscular fungus from four genera of Funneliformis, Claroideoglomus, Rhizophagus and Septoglomus were introduced as associated species with mahaleb, three species belonging to the genus Rhizophagus. The percentage of root colonization was 70.25% in spring and 76% in autumn. Also, the activities of acid phosphatase, dehydrogenase and urease indicated significant differences among seasons. The results showed that there is a significant positive correlation between percentage of root colonization and enzymes activities that shows influence of mycorrhizal fungi on enzymes activities in spring season. Due to the high percentage of mycorrhizal colonization in Cerasus mahaleb, dependence of this species on mycorrhizal symbiosis is essential and should be considered seriously in planting and rehabilitation programs.

Native juniper of Maymars is one of the valuable species in Mountainous forests of Golestan province and is one of the main pillars of natural ecosystems of Iran’s mountainous forests. At the moment most of these trees have the hardest biological conditions and they try to be survived. So it is needed to practice to find the protection and propagation ways to keep this plants.
Material and To recognize the best season and substrate, and also proper treatment to root the cuttings of Maymars, recent experiment was done with 5 levels of indole butyric acid (0, 1000 ppm, 2000 ppm, 4000 ppm & 8000 ppm) in 4 substrates contained perlite, perlite-cocopite (1:1), Pumice and rooting substrate (combination of sand, perlite, cocopeat, vermicompost and peat moss) and 4 seasons of year on Maymars cuttings with length 15 cm. The experiment was done in 3 replications, and each one contained 9 cuttings. The aim of the experiment was finding the best season; substrate and natural treatment to asexual propagate of this plant (cutting). At the end of each season, rooting percentage, root length, root numbers, fresh and dry weights of roots in each substrate and treatment were registered.
The result showed that the best season for rooting the Maymars cuttings is spring and the best substrate is perlit cocopeat (1:1). The best rooting between all treatments was related to level 4000 and 1000 ppm of indole butyric acid in spring with more than 50% rooting. Lowest amount of rooting was related to all treatments of winter with fewer than 2%. Highest number of roots was seen in spring and level of 2000 ppm of indole butyric acid and also in perlit - cocopeat substrates (1:1) and the fewest one was seen in pumice substrate. Maximum root length was seen in spring and it should be mentioned that between all substrates, the best ones were perlit – cocopeat, perlite and rooting substrate without any significant difference. Highest amount of root fresh and dry weight was resulted in spring. And also highest amount of root fresh weight was found in rooting substrate. On the other hand, highest amount of root dry weight was seen in pumice substrates as well.
So it can be concluded that to propagate Maymars cutting, spring is the best season with the best result of rooting. Also indole butirice acid is effective Plant Growth Regulator to propagate Maymars juniper. The best rooting between all treatments was related to level 4000 and 1000 ppm of indole butyric acid in substrate of perlit cocopeat (1:1) in spring with more than 50% rooting.

The objective of this study was to investigate the effects of season and age at first calving on parameters of Wood function in fitting lactation curves (such as persistency, peak time and peak yield) of primiparous Iranian Holsteins. A total of 580,980 test day records from 953 herds recorded on 58,098 cows calved between 1990 and 2012, were analyzed. Genetic analysis was performed in a univariate animal model using DMU package. The results showed that the effects of herd, year and season of calving, age at first calving and Holstein gene percentage on lactation curve parameters were significant (P

Various factors, including photoperiod, temperature, nutrition, Body condition and age, are responsible for reproductive behaviors of animals. Environmental, physiological and social factors regulate the onset and sustain of reproductive season. Photoperiod and temperature are key environmental factors, but the first one is more important (Hafez and Hafez 2009). The regulation of reproductive activity by phototherapeutic messages due to secretion of melatonin from the pineal gland in most mammals has been reported, but this relationship is not well known in the horse (Diekman et al., 2002(. Regarding the role of the melatonin hormone in the reproductive process, in this study the aim was to investigate the changes in the concentration of the serum melatonin hormone in the Arab stallion, in three age groups including 2 to 6, 6 to 10 and 10 to 14 years old. The study was conducted under natural photoperiod in the seasons of the summer and winter in the Dezful region.
Material and This research was carried out using 33 Arab stallions in three age groups including 2 to 6, 6 to 10 and 10-14 years old under the same nutrition and management condition in the July and January (2012) were as the representative of the heating and cold season, respectively. The experiment done in the Arab horse breeding fields of Dezful. The concentration of melatonin from serum samples was measured by HPLC (Bechgaard et al 1998; Itoh et al 1999; Peniston-Bird et al 1993 and Gupta et al 2006). The results of this research were analyzed using SPSS software (version 18). Comparison of serum melatonin concentration between the summer and winter seasons done by T-test. The difference of these parameters in two seasons, and in three age groups 2 to 6, 6 to 10 and 10 to 14 years old was analyzed with one-way ANOVA and multi-domain tests Duncan.
The results showed that mean serum concentration of melatonin hormone in winter (97.39 ± 16.4 pg/ml) non significantly was higher than summer (20.11±12.3 pg/ml). Research (Casao et al 2010; Altinsaat et al 2009; Elkon et al 2011; Wrench 2007; Cigdem et al 2009; Gerlach and Aurich 2000; Nagy et al 2000 and Guerin et al 1995) on changes in melatonin hormone and seasonal reproduction of Horse, were considered 8 hours of difference during the day between summer and winter seasons, as a factor for significant changes in the concentration of melatonin hormone and horse reproductive activity. Since, in the city of Dezful, the difference in the length of the day in summer (July) and winter (January) is approximately four hours, it can probably be argued that the difference in the length of the day (the duration of lighting) in The hot and cold season is not such as to make a statistically significant difference in the level of serum melatonin of Arab stallion between two seasons. The results indicate that the season has affected on the level of blood hormones, sexual behavior, physical and biochemical properties of semen and its fertility (Hafez and Hafez 2009). In addition, reproductive activity of the horse throughout the year continued with the fact that the size of the testicles, the number of Leydig cells, testosterone concentrations, and therefore the volume and concentration of sperm in the winter, decreased (Wrench 2007). In this study, in both seasons, the mean concentration of melatonin in the 2 to 6 year old stallion was significantly more than 6-10 years old and 10-14 years old (P Due to the shorter photoperiod in winter than summer, a rise in the level of melatonin in this season was seen, but photoperiodic changes between the two seasons are not so significant that the melatonin hormone exhibits significant changes. Therefore, it can be said that in the Arab stallion, the season has no effect on the concentration of serum melatonin, but it decreases with increasing age of melatonin concentration.

In this study, Seasonal variations in the liver and muscle fatty acid composition of Barbus sharpeyi were determined. The samples were collected in the middle month of each season during 2014-2015 and Total fatty acid compositions were investigated by a gas chromatographic method. The most abundant fatty acids in the (SFAs) of the liver and muscle were at the highest in the winter and not significant difference with summer, autumn (P≥0.05). The total monounsaturated fatty acids (MUFAs) were at the highest in the autumn for liver and muscle (P

Wheat bran is a by-product of conventional milling and is commercially available in large quantities. Milling of one million tons of wheat, can yield 0.25 million tons of wheat bran (Javed et al. 2012). Beside its high content of dietary fibre it contains proteins, minerals as well as vitamins (Pomeranz 1988). Wheat bran has a different nutritional value, which is due to climatic conditions, wheat type, wheat variety, storage and etc. Also wheat bran is a feed with high digestibility fiber and palatability with a wide range of applications. Due to its relatively low price, More than 95% of it is used as animal feed. Wheat bran, which consists almost entirely of the coarse outer coating of the wheat kernel, is one of the important livestock feeds.On the other side, goat milk production is a growing industry that is very important to the wellbeing of people worldwide and is an important part of the economy in many countries. The aim of the investigations is to provide an integrated analysis of the major aspects in this field to highlight unexploited nutritional potential of goat milk and the need for improvements, particularly in food safety. Goat milk like cow milk delivers many nutrients with relatively low energy content, and is relevant to the health of consumers (Silanikove et al. 2010). In order to reduce costs in the animal husbandry (especially in the case of dairy goat), it was decided to replace the wheat bran instead of barley in the concentration of Saanen goats. Therefore this experiment follows two goals and was carried out in two stages. In the first step, the nutritive value and chemical composition of different wheat brans produced in flour factories of Khorasan Razavi province were compared in summer and winter using common laboratory methods. In the second step, the effect of replacing various levels of barley with wheat bran in mixed concentrate of Saanen goats was studied.
Material and The chemical composition, gas production parameters and factors estimated from gas production of different wheat brans obtained from 8 flour factories were determined using a completely randomized design with 8×2 factorial arrangement. Changes in body weight, milk production and milk composition of Saanen goats and the effect of substituting different levels of barley with summer wheat bran in the concentrates of under study was investigated using a completely randomized design.
There were a significant differences between all chemical compositions of different wheat brans (with the exception of crude fat) in various factories (P0.05), although the DM, NDF, ADF and CP (%) in the samples was significantly higher in summer than winter (P Wheat bran samples produced by different flour factories in two seasons of the year yielded various nutritive values. Bartnick and Jacobzick (1989) also stated that the difference in the value of wheat bran produced in flour mills could be due to the difference in the stages of crushing wheat in different factories. It was also identified that the replacement of barley with wheat bran in the diet, did not have any effect on body weight, milk production and milk composition. Different researchers believe that in the case of medium-quality diets, goat is the most highly digestible among other ruminant species (Devendra 1978; Illius and Gordon 1991).Whether the barley grain in concentrate can be replaced by wheat bran up to a level of 50 percent in the ration concentrate of Saanen goats needs to be further studied in the future. Similarly, the reasons underlying the difference between bran compositions produced in different factories in different seasons or regions of varying climates need to be further explored.

BAKGROUND: Age and season may affect the thyroid gland, which regulates the metabolism of the body.
The experiment was conducted to study the effects of age and season on the concentration of thyroid hormones T3, T4, T3uptake, T3/T4 and free thyroxin index (FTI).
Blood samples were collected from jugular vein of 21 healthy purebred Arabian male horse in summer (July) and winter (January). The male horses were under the same management and feeding program in three age groups 2-6, 6-10 and 10-14 years. After centrifugation of blood samples and isolation of serum, the concentration of thyroid hormones were measured in serum by standard radio immunoassay (RIA) method.
Results showed that there is significant differences in mean values of serum T4, T3uptake and T4/T3 ratio between summer and winter seasons (P>0.05). The concentration of T3 and free thyroxin index (FTI) did not show a statistically significant differences between summer and winter (P>0.05). In summer, the concentration of T4 and FTI value in 2 to 6 years and the ratio of T4 to T3 in 10 to 14 years old males had significantly differences than other ages (P>0.05). In winter, there were not significantly differences for thyroid parameters among various ages of males (P>0.05).
The results of this study showed that under constant conditions, thyroid gland performance may be affected by season and ages in Arabic male horses.