نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه تغذیه دام و طیور، دانشکده علوم دامی، دانشگاه علوم کشاورزی و منابع طبیعی گرگان، گرگان، ایران
2 گروه تغذیه دام طیور، دانشکده علوم دامی، دانشگاه علوم کشاورزی منابع طبیعی گرگان، گرگان، ایران
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
This study aimed to compare the effect of different fat sources on vital signs, biochemical and hematological blood parameters of pregnant and non-pregnant ewes under heat stress conditions. For this purpose, 40 ewes were selected (20 three-month pregnant and 20 non-pregnant). This experiment was conducted according to a four-by-two factorial experiment based on a completely randomized design with five replications. The treatments included: 1- control diet, 2- diet containing 6% safflower seeds, 3- diet containing 1.5% safflower oil and 4- diet containing 1.5% palm oil. The animals were kept for 42 days. According to the results of the present study, the body temperature, heart rate and breathing rate of the ewes were not affected by the physiological state and the type of fat consumed. The concentration of glucose, triglyceride and blood urea in the non-pregnant group was higher than in the pregnant group (P≥0.05). Ewes receiving different fat sources had higher cholesterol, triglyceride, urea, total protein, albumin and globulin concentrations than the control (P≥0.05). The concentration of beta-hydroxybutyrate, non-esterified fatty acids, malondialdehyde and total antioxidant capacity of pregnant ewes was higher than that of non-pregnant ewes (P≥0.05). No significant difference was observed between pregnant and non-pregnant ewes in cortisol and insulin concentrations. Adding different sources of fat decreased the concentration of cortisol, malondialdehyde, non-esterified fatty acids and increased the total antioxidant capacity. In general, according to the present results, the use of different sources of fat in pregnant and non-pregnant ewes reduced the negative effect of heat stress on the measured parameters.
کلیدواژهها [English]
Extended Abstract
Objective
Climate change caused by greenhouse gas emissions is an event that affects the production of animal-based food and food security in general. Global warming creates climatic conditions and intensifies heat stress for domestic animals. As a result, high temperatures can negatively affect livestock growth and productivity, because with thermoregulation mechanisms' activation, dry matter intake decreases and energy demand increases. Heat stress occurs when the temperature and relative humidity of the air, wind, and sunlight change, such that the neutral zone, defined as the area of heat production and heat loss from the body, changes. Information on dry air temperature and relative humidity, wind speed, and rainfall help diagnose heat stress; but the combination of dry air temperature and relative humidity gives the temperature-humidity index. Also, the blood parameters of livestock are sensitive to changes in environmental temperature and play an important role in physiological responses to stressors. This study was designed to investigate the effects of feeding different fat sources on vital signs, biochemical and hematological parameters of pregnant and non-pregnant ewes. Specifically, the effects of different fats such as palm oil and safflower seed on parameters such as glucose concentration, triglycerides, cholesterol, plasma proteins, antioxidant capacity and liver enzymes in pregnant and non-pregnant ewes were investigated.
Method
For this purpose, forty Dalagh ewes (20 three-month pregnant and 20 non-pregnant) were selected. This experiment was conducted in a four-by-two factorial experiment based on a completely randomized design with five replications. The treatments included: 1- basal diet without fat supplement, 2- basal diet containing 6% safflower seeds, 3- diet containing 1.5% safflower oil, and 4- basal diet containing 1.5% palm oil. The animals in each group were kept in individual cages for 42 days. The daily feed was supplied to the animals in a completely mixed form, and fat supplements were provided to the animals daily. A digital thermometer was used to measure rectal temperature, which was placed in the animal's rectum and its temperature was recorded immediately. The heart rate was measured by placing a stethoscope in the chest area of the animals. Respiratory rate was assessed by visual observation of the number of times the animal's flanks rose and fell in one minute. Blood samples were taken from the jugular vein of pregnant and non-pregnant ewes in the final week of the period, four hours after morning feeding (at peak heat).
Results
According to the present study, body temperature, heart rate, and respiratory rate of ewes were not affected by physiological status and type of fat consumed. Blood glucose, triglyceride, and urea concentrations were higher in the non-pregnant group than in the pregnant group (P≥0.05). Different fat sources could also affect the concentrations of cholesterol, triglyceride, urea, total protein, albumin, globulin, and the ratio of these two (P≥0.05). Among these, ewes receiving palm oil and safflower seeds had higher cholesterol concentrations than the other two groups (P≥0.05). The triglyceride concentration of ewes receiving palm oil was higher than the other three groups (P≥0.05). The interaction effect of physiological status and type of dietary fat caused significant differences in blood parameters such as glucose, cholesterol, triglyceride, urea, total protein, albumin, globulin, and the ratio of these two (P≥0.05). According to the results of the present study, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) were not affected by the physiological status of ewes, nor was HDL affected by the interaction effects. Meanwhile, the very low-density lipoprotein concentration of non-pregnant ewes was higher than that of pregnant ewes (P≥0.05). According to the results of the present study, the LDL concentration of pregnant ewes × palm oil also increased under the interaction effects (P≥0.05); however, this difference was not significant with pregnant ewes × safflower seed, non-pregnant × safflower seed, and non-pregnant × safflower oil. According to the results of the present study, the white blood cell concentration of pregnant ewes in the control group and those receiving different sources of fat also increased under the interaction effects with non-pregnant × palm oil (P≥0.05); however, this difference was not significant with non-pregnant × control, non-pregnant × safflower seed, and non-pregnant × safflower oil. According to the results of the present study, the concentration of beta-hydroxybutyrate, non-esterified fatty acids, malondialdehyde, and total antioxidant capacity of pregnant ewes was higher than that of non-pregnant ewes (P≥0.05), although there was no statistical difference between the cortisol concentration of pregnant and non-pregnant ewes. The concentration of alanine transaminase enzyme in the liver of ewes was not significantly affected by the physiological status, type of fat and their interactions, and the concentration of aspartate aminotransferase in the liver was not affected by the physiological status of ewes.
Conclusions
Considering the positive effects of fat sources on cortisol and total antioxidant capacity, using these sources is recommended during heat stress.
Author Contributions
Conceptualization, Taghi Ghoorchi., and Abdolhakim Toghdory.,methodology, Katayoun Mehrani and Taghi Ghoorchi software, Katayoun Mehrani and Abdolhakim Toghdory.;validation, Taghi Ghoorchi., and Abdolhakim Toghdory.; formal analysis, Katayoun Mehrani and Abdolhakim Toghdory.; investigation Katayoun Mehrani and Taghi Ghoorchi., resources, Katayoun Mehrani and Taghi Ghoorchi.;data curation, Taghi Ghoorchi.; writing—original draft preparation, Katayoun Mehrani., writing—review and editing, Taghi Ghoorchi.; visualization, Taghi Ghoorchi.; supervision, Taghi Ghoorchi.; project administration, Taghi Ghoorchi.; funding acquisition, Katayoun Mehrani and Taghi Ghoorchi. All authors have read and agreed to the published version of the manuscript
Data available on request from the authors.
We would like to thank the Faculty of Animal Sciences, Gorgan University of Agricultural Sciences and Natural Resources, for providing the field and laboratory facilities for this research.
The study was approved by the Ethics Committee of Gorgan University of Agricultural Sciences and Natural Resources. The authors avoided data fabrication, falsification, plagiarism,and misconduct.
The author declares no conflict of interest
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