Effect of dietary fish oil on the expression of genes involved in lipid metabolism in liver and skeletal muscle of lactating sows

Abstract

This study investigated the hypothesis that dietary supplementation of fish oil as a source of n-3 polyunsaturated fatty acids (PUFA) influences the expression of target genes of sterol regulatory element-binding proteins (SREBP)-1 and (SREBP)-2 involved in triacylglycerol (TAG) synthesis and fatty acid and cholesterol metabolism in the liver, and moreover activates the expression of target genes of peroxisome proliferation-activated receptor (PPAR)-α involved in TAG and fatty acid catabolism in liver and skeletal muscle. Twenty lactating sows were fed a control diet or a fish oil diet with either 50 g of a mixture of palm oil and soya bean oil (4:1, w/w) or fish oil per kg. The diet of the fish oil group contained 19.1 g of n-3 PUFA (mainly 20:5 n-3 and 22:6 n-3) per 100 g of total fatty acids, while the diet of the control group contained 2.4 g of n-3 PUFA (mainly 18:3 n-3) per 100 g of total fatty acids. The fish oil group had reduced relative mRNA concentrations of various target genes of SREBP-1 involved in fatty acid and TAG synthesis in comparison with the control group (p < 0.05). Relative mRNA concentrations of target genes of PPARα involved in fatty acid catabolism in both liver and muscle, and mRNA concentrations of target genes of SREBP-2 involved in cholesterol synthesis and uptake were not influenced by fish oil supplementation. Concentrations of cholesterol and TAG in plasma, fat content of milk and weight gains of litters during the suckling period were not different between the two groups of sows. In conclusion, this study suggests that fish oil has only minor effects on hepatic lipid metabolism, which are non-critical with respect to milk production in sows.

The diets of sows with fish oil might decrease the oxidative stress and inflammatory response in sows, but increase the susceptibility to inflammatory response in their offspring

“…Tanghe et al (2013) reported that the perinatal sows' diet with sh oil had no effect on the oxidative stress state of sows [13]. However, the inconsistent reports found that dietary sh oil had no effect on the expression of genes related to cholesterol synthesis and absorption in the liver of lactation sows, but had minor effect on the hepatic lipid metabolism which had no effect on the milk production of sows [14]. Shen et al (2015) suggested that the supplementation of olive oil in the maternal diets signi cantly reduced IL-1β and TNF-α in the milk, but increased the oxidative stress of sows in sh oil group [15].…”

Dietary Fish Oil Inhibits Pro-Inflammatory and ER Stress Signalling Pathways in the Liver of Sows during Lactation

“…In experiment 2, twenty second parity sows (Large White and German Landrace) were used and artificially inseminated as described recently in more detail [ 35 ]. In brief, after farrowing the sows were randomly divided into two groups (control group and fish oil group) of 10 animals each, and litter sizes were adjusted to 8 piglets per sow and the sows of the two groups received two different diets throughout lactation.…”

“…In the control group, the diet contained 50 g of a mixture of palm oil and soybean oil (4:1, w/w, both oils were obtained from Henry Lamotte Oils GmbH, Bremen, Germany) per kg, whereas in the fish oil group the diet contained 50 g of fish oil (‘Marine oil’, obtained from Henry Lamotte Oils GmbH) per kg. A full description of the housing condition, diet composition, and feeding regime can be found in our recent publication [ 35 ]. In addition, data on daily feed intake, body weight development and energy balance of the sows have been reported there [ 35 ].…”

“…A full description of the housing condition, diet composition, and feeding regime can be found in our recent publication [ 35 ]. In addition, data on daily feed intake, body weight development and energy balance of the sows have been reported there [ 35 ]. All efforts were made to minimize suffering.…”

Effect of a negative energy balance induced by feed restriction in lactating sows on hepatic lipid metabolism, milk production and development of litters

“…Characteristics of primers used for qPCR analysis were as described recently (Rosenbaum et al 2013;Gessner et al 2015), except of primers for LDLR (for: 5ʹTGC GAA GAT ATC GAC GAG TG-3ʹ; rev: 5ʹTAC GGT CCA GGG TCA TCT TC-3ʹ). Characteristics of primers used for qPCR analysis were as described recently (Rosenbaum et al 2013;Gessner et al 2015), except of primers for LDLR (for: 5ʹTGC GAA GAT ATC GAC GAG TG-3ʹ; rev: 5ʹTAC GGT CCA GGG TCA TCT TC-3ʹ).…”