Blood Lipid Components and SREBP-1 Gene Expression in Broiler Chickens Fed Different Dietary Lipid Sources

Abstract

Background: Liver plays an important role in energy homeostasis. Intense liver diseases are accompanied with lower concentrations of n-3 and n-6 poly unsaturated fatty acids (PUFA). It has been found that n-3 PUFA play importantly protective roles in the liver. There was limited information about the effects of lipid sources on serum lipid components and liver sterol regulatory element binding-1 (SREBP-1) gene expression. Therefore, the aim of this study was to evaluate and compare the effects of fish oil, corn oil, olive oil and tallow, respectively, as dietary sources of n-3, n-6, n-9 and saturated fatty acid on serum lipid compound and liver SREBP-1 gene expression in broiler chicks.Materials, Methods & Results: In a completely randomized design, 240 one-day-old broiler chicks were allocated to five dietary treatments, four replicates and 12 chicks per each. Dietary treatments included of: control (diet without lipid supplementation) and diet supplemented with fish oil as a n-3 fatty acid source, corn oil as a n-6 fatty acid source, olive oil as a n-9 fatty acid source and tallow as a saturated fatty acid which were added to diets at 1.5, 3 and 4% in the starter, grower and finisher, respectively. At days 28 and 42 of age, liver tissue was dissected out and samples were placed in liquid nitrogen, also blood samples were collected. The SREBP-1 mRNA expression in liver tissue was quantitated using RT-PCR. Broilers fed diets containing fish oil, corn oil and olive oil as unsaturated fatty acid sources had lower concentrations of triacylglycerol than those fed other diets. Also, diets containing fish oil and tallow showed the lowest low density lipoprotein (LDL) levels at day 28 of age. Diets containing corn oil and olive oil showed higher levels of cholesterol and high density lipoprotein (HDL) than other diets but, these differences were not significant at days 28 and 42 of age (P ≥ 0.05). In both sampling periods, the chickens fed diets containing tallow expressed higher (P < 0.05) SREBP-1 gene as compared to those fed other dietary lipids. Broilers fed diet containing corn oil had higher (P < 0.05) SREBP-1 gene expression than those fed diet containing fish oil and olive oil.Discussion: Serum lipids were affected by dietary fat source. Lower concentration of serum triacylglycerols was found in broilers fed fish oil and corn oil diets as dietary n-3 and n-6 fatty acid sources. It was shown that dietary PUFA, especially n-6 and n-3 fatty acids could reduce hepatic fatty acid and triacylglycerol synthesis. Broilers fed corn oil diet showed elevated LDL levels respect with those fed fish oil or tallow at day 28 of age. The results showed that dietary polyunsaturated fatty acids and saturated fatty acids substantially affected on SREBP-1 gene expression at days 28 and 42 of age. The birds fed fish oil as n-3 PUFA source expressed lower SREBP-1 gene compared with other groups at day 28 of age. Longer chain length, high number of double bonds, and the presence of the first double bond gives these fatty acids distinct and unique properties that separate them and their metabolic products from the more common n-6 and n-9 fatty acids. The finding of this study indicated lipogenic effects of tallow and then corn oil. The results confirmed that each of dietary lipid sources had different effect on serum lipid components. It was also found that SREBP-1 gene expression is age-dependent and it increased as age of broilers increased.

Inclusion of vegetable oils in diets of broiler chicken raised in hot weather and effects on antioxidant capacity, lipid components in the blood and immune responses

“…Cholesterol level was the highest in chickens fed palm oil and the lowest in those received olive oil. In contrast to our finding, researchers who found that diets containing different lipid sources did not affect blood cholesterol values (Sadeghi et al, 2014;Moslehi et al, 2016). In general, these results agree with the findings of other authors who reported changes in the concentration of serum lipids of chickens with the dietary lipid sources differing in their degree of saturation (Adeyemi et al, 2016;Tari et al, 2020).…”

“…Lower concentration of serum triacylglycerol was found in broilers fed diets containing flaxseed oil, corn oil and olive oil as dietary n -3, n-6 and n-9 fatty acid sources. Consistence with our result, Moslehi, Sadeghi, Shawrang, and Aminafshar (2016) showed that dietary Pufa may reduce hepatic fatty acid and triacylglycerol synthesis. Moreover, an inhibition of the activity of Δ 9 -desaturase, which leads to a limited triacylglycerol secretion from the liver to the blood reported, also, PUFAs may show a higher rate of β-oxidation and as a result a higher rate of uptake of triacylglycerol from blood stream to tissue compared with saturated fatty acids such as those found in palm oil.…”

Effects of single‐species microalgae diet on accumulation of lipid and carotenoid and expression of lipid‐related genes in Nan'ao Golden ScallopChlamys nobilis

“…For the SRB-like-3 gene, the relative expression of the SRBlike-3 gene was positively correlated with PUFA content of the adductor muscle. This observation is consistent with Spady et al (1999) and Moslehi et al (2016) who reported that a diet rich in PUFA upregulated the expression of SRB-like-3 gene. It is worth noting that, except for intestine, the up-regulation of SRB-like-3 expression was not associated with high TCC.…”

Dietary vegetable oils inclusion on the performance, hormonal levels and hsp 70 gene expression in broilers under heat stress

“…Some studies speculated that inclusion of vegetable oils in broiler diets could enhance the performance (Ailhaud et al, 2006;He, Yang, & Guo, 2007), increase the function of immune system and antibody titer production (Sadeghi, Mirmohseni, Shawrang, & Aminafshar, 2013) and improve the health status (Moslehi, Sadeghi, Shawrang, & Aminafshar, 2016) in normal and heat stress conditions. In contrast, some reports (Sijben, De Groot, Nieuwland, Schrama, & Parmentier, 2000) rejected mentioned benefits.…”