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Все статьи: 898
Статья научная
Background: The present study investigated the effects of four days of fasting on colonic temperature (CT) and body weight responses in 20 adult male Rouen ducks (Anas platyrhynchos domesticus) during the hot-dry (12:12 light/dark cycles) and cold-dry (harmattan) (11:13 light/dark cycles) seasons under natural light/day cycles in tropical conditions. The ambient temperature and relative humidity of the pen and the CT of the ducks were recorded bihourly for four days before fasting and subsequently for another four days during fasting. During the fasting period food was completely withdrawn from the ducks at 06:00 h for four days (96 h), but the ducks were given access to clean drinking water ad libitum throughout the fasting period. Results: A major finding in the present study was that four days of food deprivation, photoperiods, season and duration of fasting did not induce hypothermia or changes in circadian rhythmic pattern of CT in the Rouen ducks. The result, for the first time, suggests that circadian modulation of fasting-induced hypothermia was lacking in Rouen ducks. The mesor and amplitudes of CT obtained during both the harmattan and hot-dry seasons before fasting were not different (P > 0.05) from those obtained during fasting. The acrophases in both seasons before and during fasting were restricted to the photophase at 14:00 h, except for the acrophase in fasted ducks during the hot-dry season, which was delayed to 16:00 h. Body weight of the ducks decrease significantly (P > 0.05) only on the 4th day of fasting. Conclusion: Overall, unlike other birds and mammals, the Rouen ducks showed greater starvation resilience, apparently due to an unknown component of fasting resistance or regional heterothermy. Future studies to elucidate the mechanism by which Rouen ducks were resistant to fasting are still required.
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Effects of Ni2+ toxicity on hill reaction and membrane functionality in maize
Статья научная
Soil contamination with heavy metals has become a worldwide problem, leading to losses in agricultural yield and hazardous health effects as they enter the food chain. Nickel as an essential trace element, affect a number of biochemical and physiological processes in plants in toxic levels. The most common symptoms are chlorosis, and inhibited photosynthesis and respiration. Zea mays seeds were germinated and cultured on nutrient solution with nickel concentrations of 50-200 μmol for a period of two weeks. Studied physiological makers included photosynthetic pigments content, the rate of Hill reaction, K+ efflux and carbohydrate leakage from the roots to the external solution and cell death as a Ni-induced membrane damage. By increasing Ni concentration up to 100 μmol, the content of chlorophyll a increased, but decreased at 200 μmol Ni. No significant changes in chlorophyll b and carotinoids content observed. The rate of Hill reaction as an ability of chlorophyll a in the reaction center of PSII680 to split water, decreased by increasing Ni concentration. Different concentrations of nickel increased the K+ efflux and sugar leakage from roots to the culture and the cell death of root tips. The present results suggested that the disruption of photosynthesis by Ni cannot be attributed to any single factor and appears to result from its combined effects on chloroplast structure, chlorophyll content and photosynthetic protein complexes and treatment with different levels of nickel may induce structural damage and alterations in membrane properties by generation of reactive oxygen species.
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Effects of Pseudomonas putida and Vitazyme® on growth and development of the potato tuber moth
Статья научная
The ability of Pseudomonas putida strain BTP1 and the biostimulant (Vitazyme®) to protect potato plants from the potato tuber moth Phthorimaea operculella (PTM) (Zeller) was investigated. Significant negative effects on survival, pupal weight, and fertility of the insect were observed between treatments and control. The results revealed that the BTP1-treated foliage had significantly the highest negative impact on PTM development and reproduction compared to other treatments. The combination of BTP1 and Vitazym® did not result in a synergistic detrimental effect on potato tuber moth reproduction. However, the biostimulant and BTP1 treatments showed the largest negative effects on PTM reproduction due to the density of hairs and trichomes on the treated foliage. Application of BTP1 and Vitazyme® could be a potential tool to reduce the use of insecticides and enhance integrated pest management against potato tuber moth.
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Статья научная
Background. Diabetes mellitus has been a menace to healthy human condition from antiquity. There has been continuous search for plant medicinal substances for drug development with an aim to managing this ailment with minimal drug side effects. In this research work, effects of fractions of aqueous root-bark extract of Nauclea latifolia on blood glucose, lipid profile and serum liver enzymes in diabetic rats were investigated. Thirty -five Wistar albino rats weighing 164.1 - 171.6 grammes were used for this study involving aqueous root-bark extract fractions A, B, C and D. The rats were divided into 7 groups of 5 rats each. Group 1 was normal non-diabetic control, group 2 was diabetic control and groups 3, 4, 5 and 6 were rats treated with 250 mg/kg body weight of varying root-bark fractions while group 7 was diabetic rats treated with 5mg/kg. body weight of glibenclamide, the standard anti-diabetic drug. Fasting blood glucose levels were determined using digital glucometer (Acuu-chek, Mannheim, Germany). Lipid profile was determined using standard procedures. Serum liver enzymes were determined using assay kits. Fraction A was analyzed using gas chromatography- mass spectroscopy and nuclear magnetic resonance spectroscopy.
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Effects of exercise on cardiovascular dysfunctions induced by cigarette smoking
Статья научная
Abstract - Smoking is known to adversely affect many organs and systems in human, where the cardiovascular system is one of the important targets. However, the exact mechanisms by which cigarette smoke alters myocardial and endothelial cells function and induces cardiovascular pathology are not clear. There are no reports especially with nitric oxide (NO), uric acid and hemodynamics after acute exercise in smokers up to date. This study is designed to investigate the role of oxidative stress, NO and uric acid in the pathophysiologic mechanisms of smoking- induced cardiovascular diseases. 40 apparently healthy subjects were studied. Depending on their previous physical conditioning status subjects were divided into equal four groups (n=10), physically active nonsmokers, physically active smokers, sedentary nonsmokers and sedentary smokers. Exercise tolerance was evaluated for each subject by using a running race (3 kilometers) after a worming up period of 5 minutes. The obtained data revealed that regular exercise significantly decreased the plasma malonaldehyde, total cholesterol, LDL and uric acid levels below sedentary levels. Pre and post race plasma level of malonaldehyde and uric acid levels were significantly increased, while, plasma glutathione and NO were decreased in sedentary smokers than the sedentary non smokers, physically active smokers and physically active non smokers. These findings point to the role of NO, uric acid and lipid peroxide in the pathophysiologic mechanisms of smoking induced cardiovascular diseases. Sedentary smokers may be at an even greater risk of oxidative stress-related cardiovascular diseases. Finally, every body should include in a regular exercise.
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Статья научная
By regulating the pineal hormone, photoperiods affect many physiological characteristics in small mammals. Thus, melatonin might take part in the thermoregulation of seasonal variations in small mammals. This study determined the influence of melatonin treatment on thermogenic pattern, we measured body mass, thermogenic activities and hormone concentrations of Eothenomys miletus were given exogenous melatonin (MLT) for 28 days. The results shown that body mass was reduced significantly, whereas resting metabolic rate (RMR) and nonshivering thermogenesis (NST) increased at 28 days in MLT group compared to control group as well as the oxidative capacities of mitochondria in liver and brown adipose tissue (BAT) were enhanced; the contents of total and mitochodrial protein increased markedly. Melatonin treatment significantly increased the State 3, State 4 respiration of liver mitochondria, and the activity of cytochrome C oxidase (COX) in liver; but the α-glerocephasphate oxidase (α-PGO) capacity showed no differences during the acclimation in liver. Furthermore, the State 4 respiration, the activities of COX and α-PGO in BAT increased, respectively. The activity of thyroxin 5’-deiodinase (T 4 5’-DII) in BAT increased remarkably. The serum content of thyroxine (T 4) decreased, and that of tri-iodothyronine (T 3) increased. Moreover, serum leptin levels showed no significant differences in MLT group compared to control group. Together, these data indicate that melatonin enhances thermogenic capacity in E. miletus. Our results suggested that melatonin is potentially involved in the regulation of body mass, adaptive thermogenic capacity and hormone concentrations in E. miletus.
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Статья научная
This pot experiment investigated the effect of treatment with exogenous silicic (Si) and/or salicylic acids (SA) on dry matter (DM), nitrogen yield (NY) and soil N uptake from soil (Ndfs) and from fertilizer (Ndff) nitrogen use efficiency (%NUE) of barley plants ( Hordeum vulgare L.) grown under varying levels of watering regimes (high stress I1, mild stress I2 and well-watered I3). Results showed that, foliar application of Si and/or SA markedly improved the overall studied growth parameters of barley plants and decreased the water-deficit influences. The synergistic effects of Si + SA application were more effective as compared with Si or SA applied separately indicating that Si and SA supports each other’s in improving plant performance which was more pronounced under high water-deficit than other watering regimes. A proper application of Si and SA might represent a suitable agricultural approach and result in increased production of barley, particularly, in the semi-arid areas under rain-fed conditions.
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Статья научная
In order to explore the adaptive changes in energy metabolism and body composition in response to a gradual reduction in both ambient temperature and photoperiod, male adult tree shrews Tupaia belangeri chinensis were raised under the conditions of 30 oC and 12L:12D photoperiod (control group). The treatment group was changed from 25 oC and 16L:8D photoperiod to 5 oC and 8L:16D photoperiod (treatment group) over a period of four weeks and then maintained at those conditions for a further 4 weeks. Changes in body mass, resting metabolic rates (RMR),energy intake, and wet and dry mass of organs and tissues were measured at the end of the acclimation. Body mass in treatment tree shrews was higher than control. RMR showed significant differences between groups. No significant differences were detected in dry matter intake, energy intake, and digestible energy intake in control tree shrews during the whole acclimation period, while these parameters were significantly increased within treatment tree shrews at the end of acclimation, and were significantly higher than those in control tree shrews. Small intestine and stomach dry mass, as well as the wet mass of small intestine, heart, lung, liver and kidney were significantly higher in treatment groups than in controls, but no significant differences were found in the mass of other organs and tissues. These results suggest that increasing body mass and energy intake, together with adjusting the mass of some organs and tissues, are important physiological changes in tree shrews to adapt the changing environmental conditions.
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Статья обзорная
Heavy metals that enter the aquatic environment pose a serious threat to the biota due to their toxicity. This review reveals that various concentrations of copper and mercury at varying lengths of exposure alter the activity of protein, carbohydrate, lipid, phosphatase, and aminotransferase significantly in the different soft tissues and hemolymph of molluscs, and toxicity is metal, organ, or species specific. The alterations in the levels of biochemical constituents and enzymes suggest adaptations of molluscs to meet high metabolic needs under metal stress. The apparent sensitivity of these biochemical and enzymatic parameters’ activities suggests that they have the potential to be promising and reliable biomarkers of water pollution due to copper and mercury and can constitute an important diagnostic tool in toxicological studies. Additionally, the shells of molluscs should be considered contamination biomarkers as they sequester pollutants. A review of the literature also indicates that molluscs can be considered full-time biomonitors as they react to pollutants and can provide useful information on the water quality over time. The “Molluscs Watch” program should be included in environmental surveillance programs to keep watch on the health of the aquatic ecosystem and to protect aquatic biodiversity. This review provides an overview of the effects of heavy metals (copper and mercury) on biochemical constituents such as protein, carbohydrate, lipid, and the activity pattern of enzymes such as acid and alkaline phosphatases, aspartate, and alanine aminotransferases in molluscs.
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Статья научная
Cold temperature damage is a common problem for plant in temperate regions. Physiological responses to low temperature were investigated in sorghum to identify mechanisms of tolerance. Sorghum (Sorghum bicolorL.)seeds were soaked in different concentrations (0, 3, 6 and 12 mg L-1) of sodium selenate for 6 h before sowing, during the germination period seedlings were exposed to 4 °C or 8 °C for 7 days and allowed to recover at 25 °C for 3 days. Selenate at lower concentrations (3 & 6L-1) enhanced the growth and levels of chlorophylls, anthocyanine, sugar, proline, ascorbic acid and enzymatic activities. However, high level of selenate (12 mg L-1) exert toxic effects. The levels of non-enzymatic antioxidants (ascorbic acid and carotenoids) were increased by selenate. Low selenate (3 & 6L-1) diminished lipid peroxidation as measured by malondialdehyde. The activities of enzymatic antioxidants (ascorbic acid peroxidase and guaiacol peroxidase) in sorghum seedlings were enhanced by low level of selenate. The results showed that both enzymatic and non enzymatic antioxidants played significant roles in selenate detoxification.
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Статья научная
The experiment was conducted with two IRRI lines and two BRRI varieties at the research field of Plant Physiology Division of Bangladesh Rice Research Institute (BRRI), Gazipur during October 2010 to September 2011 in Boro season to study the low temperature as cold tolerance effect on rice at vegetative and reproductive stages. All the genotypes (IR77496-31-2-1-3-1, IR62266-42-6-2, BRRI dhan28 and BRRI dhan36) of transplanting date 30 November, 15 December and 30 December showed higher yield except 15 November transplanted rice. The 15-November transplanted rice appeared with a significant cold in the reproductive stage. Moreover, BRRI dhan28 was not found to observe as tolerant to low temperature in reproductive stage, and produced the lowest yield 0.71 t/ha and highest (39.47%) sterility. BRRI dhan36 resulted yield 2.18 t/ha and exerted its ability to withstand the jolt of cold to some extent at the reproductive phase and IR62266-42-6-2 pronounced significantly better performance compared to BRRI dhan36...
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Статья научная
Environmental cues play important roles in the regulation of an animal’s physiology and behavior. In the present study, we performed a factorial experiment (temperature/photoperiod) in which Tupaia belangeri was acclimated to different photoperiods (long photoperiod, 16L:8D; short photoperiod, 8L:16D) and temperatures (warm, 30 oC; cold,5 oC) to test the hypothesis that photoperiod, temperature, or both together can trigger changes in energy budgets and endocrine hormones concentrations. The results showed that temperature, photoperiod had a significant effect on energy intake, and digestible energy intake. Both short photoperiod and cold caused animal's gross energy intake to increase by 25.6% and 89.1 %, and caused digestible energy intake to increase by 24.1% and 83.5% respectively compared with that of the initial, but there was no significant interaction between photoperiod and temperature on energy intake and digestible energy intake. Temperature had significant effect on serum thyrotropin (TSH) concentrations, serum leptin level, photoperiod had a significant effect on TSH and melatonin. The present results suggested that T. belangeri adapt cold stress or short photoperiod by increasing energy intake, and may be regulated by endocrine hormones. Furthermore, leptin and melatonin seem to be involved in the regulation of body mass and energy balance in T. belangeri.
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Статья научная
Many small mammals respond to seasonal changes in photoperiod by altering body mass and adiposity. These animals may provide valuable models for understanding the regulation of energy balance. In present study, we examined the effect on body mass, rest metabolic rate, food intake and body composition in cold-acclimated (5 °C) in Eothenomys miletus by transferring them from a short (SD, 8h :16h L: D) to long day photoperiod (LD, 16h: 8h L:D). During the first 4 weeks of exposure to SD, E. miletus decreased body mass. After the next 4 weeks of exposure to LD, which the average difference between body masses of LD and SD voles was 4.76 g. This 14.74% increase in body mass reflected significant increases in absolute amounts of body components, including wet carcass mass, dry carcass mass and body fat mass. After correcting body composition and organ morphology data for the differences in body mass, only livers, kidney, and small intestine were enlarged due to photoperiod treatment during cold exposure. E. miletus increased RMR and energy intake exposure to LD, but maintained a stable level to SD after 28 days. Serum leptin levels were positively correlated with body mass, body fat mass, RMR as well as energy intake. All of the results indicated that E. miletus may provide an attractive novel animal model for investigation of the regulation of body mass and energy balance at organism levels. Leptin is potentially involved in the photoperiod induced body mass regulation and thermogenesis in E. miletus during cold exposure.
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Статья научная
Haematological analyses has been routinely used in determining the physiological state of animals and known to be affected by different environmental factors, the present study was therefore designed to assess the effect of 24 hours of light (00D: 24L), 24 hours of darkness (24D: 00L) and 12 hour light / 12 hours darkness (12D: 12L) photoperiod on the haematological parameters of the African Catfish. At the end of the six weeks experiment, it was observed that some haematological parameters such as Mean Corpuscular Haemoglobin Concentration (MCHC), the Mean White Blood Cells (WBC), Mean Red Blood Cells (RBC), Haemoglobin content (HGB), Platelet count (PLT) showed significant difference (P0.05). However MCHC and MCH were noticed to increase as the light period increased while the other parameters reduced as the light period increased. The findings indicate that exposure of the African Catfish to continuous light for six weeks duration elicits response in the haematological profile of the fish.
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Effects of plant growth regulators on the carbohydrate accumulation in Simarouba glauca seedlings
Статья научная
A study was conducted to assess the accumulation of carbohydrate in germinating seeds as well as leaves, stem and roots of Simarouba glauca in response to various Plant Growth Regulators (PGRs). Field experiment was carried out to investigate effect of foliar application of PGRs like 6-benzylaminopurine (6-BA), gibberellic acid (GA), chlormequat (CCC), salicylic acid (SA), cysteine and methionine with 5 and 20 ppm concentration on carbohydrate content of Simarouba glauca DC whereas Seeds were subjected to 100 ppm solutions of various PGRs, which include GA, 6-BA, CCC, SA, Cysteine, and Methionine. It could be concluded that application of PGRs affect the carbohydrate metabolism or synthesis. Thus, the application of growth regulators in present study will be beneficial for induction of synthesis of primary metabolic products followed by synthesis of secondary metabolites of S . glauca .
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Effects of pre-application with gibberellic acid on germination of soybean under salt stress
Статья научная
This study was conducted to determine the effect of GA3 applied on soybean seeds before germination in Sinop University Department of Biology Laboratory. Soybean seeds were treated with different doses of GA3 (50, 100 and 150 ppm) for three different application times (6, 12 and 24 hours). After this, soybean seeds pretreated GA3 irrigated with different doses of pure water and NaCl (50, 100 and 150 mM). Germination rate and germination time at room temperature, radicle and hypocotyl lenght, wet and dry weight of radicle, hypocotyl and cotyledon values were examined. Study, the highest germination rate was by (42.83% and 41%) and 6 hours in GA3 pre and NaCl application (pure water) group, the highest germination time (6.80 and 6.81 days) at 6 hours with control (pure water) and at 50 ppm GA3 pre and 150 mM NaCl. The highest radicle and hypocotyl length were obtained from 12 hours pre-application control (pure water) and 100 ppm GA3 dose. As a result; it has been observed that as the salt ratio increases, all the parameters decrease significantly and the soybean seed is very sensitive to salt, especially 6 hours control (pure water) and 50 ppm GA3 pretreatment provides salinity resistance.
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Статья научная
This investigation was aimed to study the response of potato plants to water deficit and exogenous application of salicylic acid (SA) and glycine betaine (GB). Potato cultivars, Spirit, Born, Arinda and Banba were experienced under two irrigation regimes, 30 and 60 % depletion of available soil water, and two concentrations of both SA (0.5 and 1.0 mM) and GB (1.0 and 2.0 mM) additionally the control (0.0 mM SA and GB). Gas exchanges, proline content (Pro), root volume (RV), root/shoot ratio (R/S), plant dry mass (PDM), number tuber (NT) and yield of potato cultivars were measured. With the exception of R/S, water de cit led to notable decreases in gas exchanges, RV, PDM, NT and yield of potato cultivars and increases in Pro content. Foliar application of SA and GB resulted in signi cant increases in photosynthesis (Photo), carbon dioxide concentration in the sub-stomatal chamber (Ci), stomatal conductance (Gs), Pro, PDM and yield in some levels of SA and GB; the level of the increases appeared more when potato plants were grown under water de cit conditions. All the overhead effects supported PDM and yield of potato cultivars to increase by exogenous application of SA and GB and directed to the assumption that water deficit converted harmful effects on potato cultivars could be released by exogenous applied SA and GB.
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Статья научная
Salicylic acid is involved in the regulation of metabolic activity and defense mechanism in plants under various stress conditions. Present study was conducted to determine the effects of salicylic acid (10 to 500 M) on seedling growth, development and nitrogen use efficiency in cucumber (Cucumis sativus L.) plants with or without nitrogen nutrient. Salicylic acid increased contents of chlorophyll, total non-structural carbohydrate and total nitrogen, as well as nitrate assimilation through the induction of nitrate reductase (EC 1.6.6.1) activity in isolated cucumber cotyledons. Accumulation of salicylic acid was two-fold higher in cotyledons without nitrate supply in comparison to that with nitrate supply. Further 50 M of SA induced enhancement in seed germination and growth characteristics. However higher salicylic acid concentrations inhibited above physiological characteristics. Results show that, field application of salicylic acid need optimum physiological concentration (e.g., 50 M) to increase nitrogen use efficiency particularly during germination and seedling growth.
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Статья научная
Present study aims to evaluate the impacts of salinity and water stress factors on seed germination and early seedling growth under ex-vitro conditions in an oil crop, black sesame ( Sesamum indicum L., cv. TMV3). During salinity stress, various concentrations of NaCl-solutions (10mM, 25mM, 50mM, 100mM, and 250mM) were employed while during water stress treatments, mannitol and sorbitol solutions in equal concentrations (10mM, 25mM, 50mM, 100mM, 250mM, and 500mM) and polyethylene glycol (PEG) solution (5%, 10%, 15%, 25%, and 50%) were considered. Furthermore, after 3-days and 7-days of stress treatments, observations were recorded as partial and full germination respectively. Results indicate that with 100mM of NaCl solution, sesame seed was found to germinate without root development (80±0.0%) after 7-days of treatments in comparison to control experiment (100±1.0%) and further high concentration (250mM) of NaCl solution was proved to be completely toxic for sesame seed germination. Additionally, seedling growth was also affected with NaCl concentrations and seedling’s height was recorded as minimum with root and shoot lengths (0.5±0.21cm/2.1±0.78cm) in seeds growing with NaCl solution (50mM) while further high concentration (100mM) was proved to be strongly inhibitory for root development in germinated seeds. During water stress treatments, results indicated that mannitol (100mM) turns out to be relatively strong inhibitor for seed germination (50±0.5%) than sorbitol (60±1.0%) with (250mM) solution. However, both mannitol and sorbitol solutions (500mM) were proved to be fully toxic for seed germination. Furthermore, during PEG treatments, PEG solution (25%) was found to be significantly inhibitory and germination frequency (40±0.0%) was recorded while further increase in PEG concentration (50%) was proved to be lethal. Moreover, during early seedling growth, mannitol (100mM) was turned out to be strongly inhibitory for root development and root-shoot length ratio was recorded as (0.0cm/0.25±0.41cm) while sorbitol (100mM) was proved to be slightly weak inhibitor (0.71±0.27cm/0.93±0.32cm). Significantly high concentration of mannitol (250mM) was turned out to be toxic for seedling growth while even very high concentration of sorbitol (500mM) was failed to suppress seedling growth completely. During PEG treatments, the minimum seedling height (0.79±0.31cm/1.43±0.32cm) was recorded with PEG (15%) solution while PEG (25%) solution was found to suppress root formation completely. Furthermore, during endogenous proline content estimation in tissues growing with NaCl salt solutions, results indicated that proline content gradually increases with the increase in NaCl concentrations and was found to be maximum (128.3x10-3g-1) in tissues growing with very high concentration of NaCl (100mM) solution than the tissues growing with very low concentration (10mM) of NaCl salt solution (10.94x10-3g-1).
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Effects of short-term low-intensity laser radiation on muscle reactions in young lambs
Статья научная
The article is based on the results of a study of the effect of short-term, low-intensity laser radiation on the meat yield of young lambs in the farm "Gulandom ona" of the Kushrabot district of the Samarkand region. Analysis of the change in body weight by age in absolute and daily growth rates showed that the lambs of the experimental group differed from the control lambs in significantly higher body weight and daily growth rates. In this case, it was shown that, according to the studied indicators, the lambs in the experimental group were significantly superior to those in the control group. It was established that the night gain obtained in the lambs of the II and III experimental groups was 3.6-4.4% higher than that in the lambs of the control group.
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