Regular vs Low alpha-Linolenic Acid Soy Oil
Regular vs Low alpha-Linolenic Acid Soy Oil
The fatty acid composition of experimental oils is presented in Table 2 . The SBO has a linoleic acid and α-linolenic acid content of 54.8 and 7.5% respectively. The LLO has a content of 60.1 and 1.5% linoleic acid and α-linloenic acids respectively. The fatty acid composition of experimental diets is presented in Table 3 . The CON, SBO and LLO diets have a linoleic acid content of 45.51, 53.59 and 56.90% respectively. The content of α-linolenic in the diets was 3.68, 7.14 and 1.95% for the CON, SBO and LLO diets respectively. The daily feed intakes across treatments were 1.55, 1.19 and 1.16 kg/day for the CON, SBO and LLO diets, respectively, and these were not different statistically. Estimated mean daily energy intakes were 4697.8, 5533.5 and 5394.0 kcal/day for the CON, SBO and LLO diets, respectively. However, because of the higher proportion of fat in the high fat diets ( Table 1 ), estimated daily fat calories consumed in the diets were 512.1, 2263.2 and 2206.2 kcal/day for the CON, SBO and LLO diets, respectively. Total energy and fat calorie intake were similar in the SBO and LLO treatments, but higher than the CON. Although pigs were allowed to eat ad libitum, the total energy intake in the SBO and LLO diets was approximately 17% higher than in the CON diet. However, the fat calorie intake was 336% higher in the SBO and LLO diets than the CON diet. As expected, the differences in fat calories and the quantities of individual fatty acids consumed indicate that these were the main determinants of responses obtained in the diets. The estimated daily intake of fatty acids is presented in Table 5 . The intake of linoleic acid in the CON, SBO and LLO diets were 27.51, 125.62 and 130.03 g/day. The intake of α-linolenic acid was 2.23, 16.73 and 4.46 for the CON, SBO and LLO diets respectively. The n6:n3 fatty acid intake ratios were 12.36, 7.54 and 29.20 for the CON, SBO and LLO diets respectively. Final mean body weights were 38.3, 40.3 and 39.3 kg for the CON, SBO and LLO treatments, respectively, and these were not significantly different.
The serum concentration of selected metabolites is presented in Table 6 . Although the SBO diet resulted in marginal increase in the serum glucose concentration relative to the CON diet, it resulted in a significant increase serum insulin concentration. The LLO diet had a lower concentration of both glucose and insulin than the CON and SBO diets (P < 0.05). However, the SBO and LLO groups had higher serum non-esterified fatty acids (NEFA) concentration than the CON group (P < 0.05). Serum triglyceride concentration was higher in the SBO group compared to LLO and CON groups (P < 0.05). Total and LDL cholesterol concentrations were higher in the SBO group than in the CON and SBO groups. However, serum C-reactive protein (CRP) concentration was lower in the SBO and LLO diets than CON diet (P < 0.05).
Serum and adipose tissue fatty acid composition are presented in Table 7 and Table 8 respectively. The content of SFA was higher in the serum from CON group that the SBO and LLO groups (P < 0.05) ( Table 7 ). Furthermore, the SBO group had a higher content of mono unsaturated fatty acids (MUFA), but a lower content of polyunsaturated fatty acids (PUFA) in the serum ( Table 7 ) and subcutaneous fat tissue ( Table 8 ), than the CON and LLO groups. Pigs in the SBO group had a higher MUFA: SFA ratio, but PUFA: SFA ratio was higher in the serum ( Table 7 ) and subcutaneous fat tissue ( Table 8 ) of pigs on the LLO diet. Additionally, pigs fed the SBO diet had a higher serum and subcutaneous fat tissue α-linolenic and oleic acid content. Serum and subcutaneous fat tissue linoleic acid content was also higher in the LLO group compared to the CON and SBO groups. However, stearic acid content was higher in both the serum and subcutaneous fat tissue of pigs on the CON diet than in those on the SBO and LLO diets. Trans10, cis12 CLA content was higher in the subcutaneous fat tissue of pigs in the CON group than in those in the SBO and LLO groups. However, cis 9, trans11 CLA content was higher in the subcutaneous fat tissue of pigs in the LLO group compared to those in the CON and SBO groups.
Expression of extracellular matrix and inflammatory genes was also determined. The expression of Col1A was lower in SBO group compared to LLO and CON groups (P < 0.05). There was also a tendency (P < 0.1) for a lower expression of COLVIA and fibronectin in the SBO treatment than the CON and LLO treatments ( Table 9 ). However, expression of two inflammatory markers, MCP-1 and CD68 was not different in the subcutaneous tissue in the different dietary groups (P > 0.05) ( Table 9 ). To determine the association fatty acid profile in the serum and adipose tissue and serum metabolite profile, a correlation analysis was conducted between these variables. Serum CRP was the only serum variable that was negatively correlated only to MUFA: SFA ratio (r = −0.53; P < 0.07). Correlation to individual fatty acids was weak (P > 0.1). The MUFA: SFA ratio was higher in both SBO and LLO diets and these diets had lower serum CRP concentration ( Table 6 ). This suggests that the overall fatty acid profile and the sum of action of individual fatty acids may be very important in determining the metabolic response to the diets.
Western blot analysis of adiponectin protein in the subcutaneous adipose tissue is presented in Figure 1. Higher expression of adiponectin protein was observed in pigs on the SBO diet compared to those on the CON diet (P < 0.05). However, similar levels were observed between the SBO and LLO groups.
(Enlarge Image)
Figure 1.
Adiponectin gene expression in subcutaneous fat depot. Expression of adiponectin in the subcutaneous adipose tissue by RT-PCR (A) or western blot (B). Bars represent mean ± SEM. Superscript letters represent significant mean differences (P < 0.05); n = 4.
Results
Fatty Acid Composition and Animal Performance
The fatty acid composition of experimental oils is presented in Table 2 . The SBO has a linoleic acid and α-linolenic acid content of 54.8 and 7.5% respectively. The LLO has a content of 60.1 and 1.5% linoleic acid and α-linloenic acids respectively. The fatty acid composition of experimental diets is presented in Table 3 . The CON, SBO and LLO diets have a linoleic acid content of 45.51, 53.59 and 56.90% respectively. The content of α-linolenic in the diets was 3.68, 7.14 and 1.95% for the CON, SBO and LLO diets respectively. The daily feed intakes across treatments were 1.55, 1.19 and 1.16 kg/day for the CON, SBO and LLO diets, respectively, and these were not different statistically. Estimated mean daily energy intakes were 4697.8, 5533.5 and 5394.0 kcal/day for the CON, SBO and LLO diets, respectively. However, because of the higher proportion of fat in the high fat diets ( Table 1 ), estimated daily fat calories consumed in the diets were 512.1, 2263.2 and 2206.2 kcal/day for the CON, SBO and LLO diets, respectively. Total energy and fat calorie intake were similar in the SBO and LLO treatments, but higher than the CON. Although pigs were allowed to eat ad libitum, the total energy intake in the SBO and LLO diets was approximately 17% higher than in the CON diet. However, the fat calorie intake was 336% higher in the SBO and LLO diets than the CON diet. As expected, the differences in fat calories and the quantities of individual fatty acids consumed indicate that these were the main determinants of responses obtained in the diets. The estimated daily intake of fatty acids is presented in Table 5 . The intake of linoleic acid in the CON, SBO and LLO diets were 27.51, 125.62 and 130.03 g/day. The intake of α-linolenic acid was 2.23, 16.73 and 4.46 for the CON, SBO and LLO diets respectively. The n6:n3 fatty acid intake ratios were 12.36, 7.54 and 29.20 for the CON, SBO and LLO diets respectively. Final mean body weights were 38.3, 40.3 and 39.3 kg for the CON, SBO and LLO treatments, respectively, and these were not significantly different.
Serum Metabolite Profile
The serum concentration of selected metabolites is presented in Table 6 . Although the SBO diet resulted in marginal increase in the serum glucose concentration relative to the CON diet, it resulted in a significant increase serum insulin concentration. The LLO diet had a lower concentration of both glucose and insulin than the CON and SBO diets (P < 0.05). However, the SBO and LLO groups had higher serum non-esterified fatty acids (NEFA) concentration than the CON group (P < 0.05). Serum triglyceride concentration was higher in the SBO group compared to LLO and CON groups (P < 0.05). Total and LDL cholesterol concentrations were higher in the SBO group than in the CON and SBO groups. However, serum C-reactive protein (CRP) concentration was lower in the SBO and LLO diets than CON diet (P < 0.05).
Serum and Tissue Fatty Acid Profile
Serum and adipose tissue fatty acid composition are presented in Table 7 and Table 8 respectively. The content of SFA was higher in the serum from CON group that the SBO and LLO groups (P < 0.05) ( Table 7 ). Furthermore, the SBO group had a higher content of mono unsaturated fatty acids (MUFA), but a lower content of polyunsaturated fatty acids (PUFA) in the serum ( Table 7 ) and subcutaneous fat tissue ( Table 8 ), than the CON and LLO groups. Pigs in the SBO group had a higher MUFA: SFA ratio, but PUFA: SFA ratio was higher in the serum ( Table 7 ) and subcutaneous fat tissue ( Table 8 ) of pigs on the LLO diet. Additionally, pigs fed the SBO diet had a higher serum and subcutaneous fat tissue α-linolenic and oleic acid content. Serum and subcutaneous fat tissue linoleic acid content was also higher in the LLO group compared to the CON and SBO groups. However, stearic acid content was higher in both the serum and subcutaneous fat tissue of pigs on the CON diet than in those on the SBO and LLO diets. Trans10, cis12 CLA content was higher in the subcutaneous fat tissue of pigs in the CON group than in those in the SBO and LLO groups. However, cis 9, trans11 CLA content was higher in the subcutaneous fat tissue of pigs in the LLO group compared to those in the CON and SBO groups.
Inflammatory and Extracellular Matrix Gene Expression in Adipose Tissue
Expression of extracellular matrix and inflammatory genes was also determined. The expression of Col1A was lower in SBO group compared to LLO and CON groups (P < 0.05). There was also a tendency (P < 0.1) for a lower expression of COLVIA and fibronectin in the SBO treatment than the CON and LLO treatments ( Table 9 ). However, expression of two inflammatory markers, MCP-1 and CD68 was not different in the subcutaneous tissue in the different dietary groups (P > 0.05) ( Table 9 ). To determine the association fatty acid profile in the serum and adipose tissue and serum metabolite profile, a correlation analysis was conducted between these variables. Serum CRP was the only serum variable that was negatively correlated only to MUFA: SFA ratio (r = −0.53; P < 0.07). Correlation to individual fatty acids was weak (P > 0.1). The MUFA: SFA ratio was higher in both SBO and LLO diets and these diets had lower serum CRP concentration ( Table 6 ). This suggests that the overall fatty acid profile and the sum of action of individual fatty acids may be very important in determining the metabolic response to the diets.
Adiponectin Expression
Western blot analysis of adiponectin protein in the subcutaneous adipose tissue is presented in Figure 1. Higher expression of adiponectin protein was observed in pigs on the SBO diet compared to those on the CON diet (P < 0.05). However, similar levels were observed between the SBO and LLO groups.
(Enlarge Image)
Figure 1.
Adiponectin gene expression in subcutaneous fat depot. Expression of adiponectin in the subcutaneous adipose tissue by RT-PCR (A) or western blot (B). Bars represent mean ± SEM. Superscript letters represent significant mean differences (P < 0.05); n = 4.