نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه علوم دامی، دانشکده علوم دامی و شیلات، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری، ایران
2 گروه علوم دامی، دانشکده علوم دامی و شیلات، دانشگاه علوم کشاورزی و منابع طبیعی ساری، ساری
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
One of the goals of the sheep industry is to maintain the quality of the meat and increase the muscle mass, as well as to create welfare for the livestock. In this research, in order to investigate the effect of glutamine and protein nutrition on the expression of adipogenic genes (PPARG, LPL, CEBP/B) in the muscle of Zel sheep under heat stress conditions. Sixteen Zel male lambs (average weight 31.5 ± 0.22 kg and age 4 ± 0.5 months) were randomly selected and subjected to four experimental treatments for forty-five days. Experimental treatments include:1) Basic diet 2) Basic diet with glutamine (0.2 grams per kilogram of body weight (, 3) 10% more protein than needed, without glutamine And 4) 10% more protein with glutamine (0.2 g/kg body weight). A thigh biopsy was taken from the thigh muscle on day 42. The relative expression of genes was measured using Real Time-PCR and using specific primers of genes. The results showed that the relative expression of C/EBPB and PPARG genes increased significantly in all treatments compared to the control treatment. Also, the relative expression of LPL gene in treatment 4 (GP) was significantly decreased compared to the control treatment. Also, feeding glutamine and protein levels by changing the expression of adipogenic genes in the muscle of Zel sheep under heat stress conditions can probably have a positive effect on meat quality.
کلیدواژهها [English]
Extended Abstract
Introduction
Currently, the most important reason for raising sheep in Iran is to produce meat. Zel sheep is one of the native breeds of Iran, which is the only tailless sheep in Iran. This breed is predominantly raised in the northern regions of Iran, mainly in Mazandaran province and rarely in Gilan province, and the main purpose of breeding this breed is to produce meat. Heat stress is a multibillion-dollar problem for the livestock industry because it impairs animal performance in the summer months and leads to global economic losses.
Inflammatory factors regulate muscle growth and metabolism. Glutamine is abundant in blood and tissues, but it is consumed quickly. Its high turnover rate is due to its wide range of metabolic functions that depend directly or indirectly on glutamine. The total amount of cellular energy derived from glutamine depends on the amount of oxidation and the amount of glutamine utilization. These factors depend largely on the absolute amounts and relative ratio of glutamine and glucose available, as well as the type and state of cell proliferation.
Skeletal muscles simultaneously participate in fat and glucose metabolism. Research has shown that glucose metabolism specific to skeletal muscles is impaired in lambs exposed to chronic heat stress. Muscle fat content, a critical indicator of meat quality, is influenced by various genes and varies significantly between individuals of the same breed. Muscle fat content also contributes to lamb flavor.
Based on this, in this research, the effect of feeding glutamine as a key metabolite responsible for a wide range of metabolic functions in the body was studied in relation to the expression of adipogenic genes (LPL, C/EBP-β, PPARγ) in the muscles of Zel sheep under heat stress conditions.
Materials and methods
In this research, 16 healthy male lambs of Zel breed (4 ± 0.5 months old) and an average weight of 31.5 ± 0.22 kg with similar physiological conditions were selected for 45 days. The animals were divided into 4 experimental groups with 4 repetitions. Experimental diets were formulated using SRNS software (version 1-9-5566). The rations were adjusted according to the recommendations of the Nutrient Requirements of Sheep (NRC, 2007) as well as the equations proposed by Cannas et al.
In order to protect glutamine, it was sprayed with 1% formaldehyde and dried at room temperature for 72 hours to evaporate any residual formaldehyde. Water was provided ad libitum.
RNA extraction from muscle tissue samples was performed using the Sinaclone commercial kit according to the manufacturer’s protocol. The RNA quality was checked using electrophoresis on a 1% agarose gel, and RNA was converted to cDNA. The clone was synthesized and then put into PCR using the cDNA program (22°C for 14 minutes). In the continuation of this step, the cDNA synthesis kit of Yektatajhiz was used, and after completing the steps, the samples were stored at -80°C.
Common thermal cycling parameters (3 min at 95°C and 40 cycles of 15 s at 95°C and 60 s at 60°C) were used to amplify each transcript. Samples were run in duplicate, and mRNA abundance was expressed relative to GAPDH as the housekeeping gene, which is stable under laboratory conditions. Data were normalized to a calibrator sample using the 2-ΔΔCt method with amplification efficiency correction.
Statistical analysis was conducted as a completely randomized design using SAS statistical software (GLM procedure). Mean comparisons were performed using Duncan's method at a 5% significance level.
Results and discussion
The average temperature-humidity index (THI) was equal to 26.82, which indicates heat stress conditions during the experimental period. Expression levels of PPARG and C/EBPB, which are key transcription factors in adipogenesis, showed significant increases in experimental treatments compared to the control group. These factors regulate fatty acid deposition and decomposition.
The study demonstrated that despite glutamine and protein supplementation, the body relies less on its reserves. Statistical analysis showed that LPL expression in the glutamine + protein treatment was significantly lower than in the control group (without glutamine and protein).
Conclusion
The findings of this research showed that dietary supplementation with glutamine and protein influences the expression of genes related to fat metabolism in skeletal muscle. Glutamine and protein supplementation improved the performance and meat quality of Zel sheep under heat stress conditions. Nutrition of glutamine and protein levels by changing the expression of adipogenic genes in the muscle of Zel sheep under heat stress conditions can probably have a positive effect on meat quality and livestock performance.
All authors contributed equally to the conceptualization, investigation, analysis, and writing of the original and subsequent drafts of the article.
Data available on request from the authors.
The authors appreciate the Sari Agricultural Sciences and Natural Resources University (SANRU) for financial support. We are also grateful to Poultry Research Farm and Laboratory Staff at SANRU for technical assistance.
The study was approved by the Ethics Committee of Sari Agricultural Sciences and Natural Resources University. The authors adhered to ethical standards and avoided data fabrication, falsification, plagiarism, and other forms of misconduct.
The author declares no conflict of interest..
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