Document Type : Research Paper

Authors

• Katayoun Mehrani ¹
• Taghi Ghoorchi ²
• Abdolhakim Toghdory ¹

¹ Department of Animal and Poultry nutrition, Animal Science Faculty, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran

² Department of Animal and Poultry nutrition, Animal Science Faculty, Gorgan University of Agricultural Science and Natural Resources, Gorgan, Iran.

Abstract

Keywords

• Blood parameters
• Dalagh ewe
• Heat stress
• Hematology
• Vital signs

Main Subjects

• Animal Nutrition and poultry

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 Availability Statement

Data available on request from the authors.

Acknowledgements

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.

Ethical considerations

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.

Conflict of interest

The author declares no conflict of interest