Effects Of Dietary Supplementation Of Fish Oil On Fat Deposition,intestinal Barrier Function And Estrus Cycle In Female Mice

Fat deposition not only has an important effect on the carcass quality and meat quality of animals,but also plays an important role in regulating the intestinal health and reproductive performance of animals.Therefore,regulating animal body fat deposition is of great significance for improving animal product quality,intestinal health and reproductive performance.The main component of fish oil is n-3 polyunsaturated fatty acids(n-3 PUFA).Previous studies on fish oil function have focused on reducing blood lipids and anti-inflammatory,while the regulatory role of fish oil in animal fat deposition,intestinal barrier function,and reproductive performance is not fully understood.Therefore,the purpose of this paper is to investigate the effects of dietary supplementation of fish oil on fat deposition,intestinal barrier function and estrous cycle in female mice.Forty-eight 6-week-old C57/BL6 J female mice were randomly divided into control group,fish oil group,high fat diet(HFD)group,high fat + fish oil group(HFD+ Fish Oil),with 12 mice in each group.The mice in the above-mentioned four groups were fed basal diet,basal diet supplemented with 5% fish oil(equal energy),high-fat diet and high-fat diet supplemented with 5% fish oil(equal energy).The test lasted for 21 weeks.The feed intake and body weight of the mice were measured weekly.The body fat content,spontaneous exercise behavior,overall energy metabolism,brown fat temperature,rectal temperature,intestinal permeability,and estrus cycle were measured during the experiment.Meanwhile,mouse feces were collected and the crude fat content and energy value were determined.After the experiment,blood,adipose tissue,and intestinal tissue were collected for examination of related indicators.The experiment results are as follows:1.Effects of dietary supplementation of fish oil on fat deposition in mice: basal diet supplemented with 5% fish oil significantly inhibited feed intake and reduced energy intake,excretion and crude fat content in feces.In contrast,HFD supplemented with 5% fish oil significantly decreased body weight and reduced energy excretion and crude fat content in feces.The results of body composition showed that fish oil significantly increased body fat content in normal diet mice,but significantly reduced body fat content,subcutaneous and abdominal fat deposition in HFD mice.The finding s of metabolic cage demonstrated that compared with normal diet,HFD can significantly reduce the heat production of mice.However,supplementation of 5% fish oil in basal diets and HFD significantly increased the oxygen consumption and heat production of mice.The results of spontaneous exercise experiments in mice indicated supplementation of 5% fish oil in basal diets and HFD in normal diets and HFD significantly increased the average speed and total distance traveled in mice.The thermographic results showed that HFD reduced the brown fat temperature of mice compared to normal diets,wiht no significant effect on rectal temperature.In addition,supplementation of 5% fish oil in basal diets and HFD could significantly increase the temperature of rectal and brown fat in mice.The results of real-time PCR revealed that supplementation of 5% fish oil in basal diets and HFD significantly increased the expression of thermogenesis-related genes(UCP1,PRDM16,PGC1α,Cidea,Elovl3)in brown fat and subcutaneous fat.Taken together,these results indicated that dietary supplementation of 5% fish oil significantly enhanced the movement of mice,promoted the production of brown fat,increased the energy metabolism of mice,and reduce the fat deposition in HFD-fed mice.2.Effects of dietary supplementation of fish oil on intestinal barrier function in mice: H&E staining showed that compared with basal diet,HFD reduced the villus height and crypt depth ratio(V/C)in jejunum and ileum.Supplementation of 5% fish oil in basal diet had no significant effect on the V/C ratio in the jejunum and ileum.However,the addition of 5% fish oil in HFD significantly reversed the HFD-induced reduction of V/C ration in jejunum and ileum.PAS staining results showed that compared with the normal diet,HFD significantly reduced the number and density of goblet cells in mice ileum,which could be rescued by 5% fish oil supplementation in HFD.Intestinal permeability findings showed that HFD significantly increased intestinal permeability and serum endotoxin levels in mice compared with the basal diets.However,the HFD-induced increase in serum levels of FITC-(Dextran)and endotoxin could be abolished by addition of 5% fish oil in HFD.Western Blot results demonstrated that HFD significantly reduced the expression of tight junction proteins in jejunum and ileum of mice compared with normal diets,which could be reversed by supplementation of 5% fish oil.Quantitative PCR results showed that compared with normal diet,HFD significantly increased the expression of proinflammatory cytokines such as IL-8,IL-6 and IL-1β,and decreased the expression of anti-inflammatory factor IL-10 in the jejunum and ileum.However,the HFD-induced changes of inflammatory cytokines expression could be reversed by supplementation of 5% fish oil.Collectively,these results indicated that dietary supplementation of 5% fish oil could alleviate the intestinal barrier function damage caused by HFD in mice.3.Effect of dietary supplementation of fish oil on the estrus cycle of mice: The results showed that compared with basal diet,HFD can significantly prolonged the estrus cycle duration,increased the time percentage of diestrus and decreased the time percentage of estrus.However,dietary supplementation of fish oil could reverse HFD-induced prolonged estrus cycle duration,increased diestrus time percentage of and decreased estrus time percentage.In addition,we found that the percentage of normal estrus cycle of mice in control and fish oil groups was 81.28% and 90.91,respectively.HFD significantly reduced the percentage of normal estrus cycle to 16.67%,while supplementation of 5% fish oil HFD could recover the percentage of normal estrus cycle to 75%.The results ELISA assay demonstrated that compared with the normal diet,HFD significantly reduced the level of E2 in the serum of mice,with no significant effect on serum follicle stimulating hormone(FSH)level.In addition,supplementation of fish oil in basal diets and HFD could both significantly increased the E2 and FSH levels in serum.Together,these results showed that dietary supplementation of fish oil could improve the estrous cycle disorder caused by HFD and increased the level of E2 and FSH caused by HFD.In summary,this study showed that dietary supplementation of fish oil could enhance energy metabolism,reduce fat deposition in mice,and effectively alleviate the damage of intestinal barrier caused by HFD.In addition,fish oil could improve the estrous cycle disorder induced by HFD.These data suggested the beneficial regulatory role of fish oil in animal fat deposition,intestinal barrier function and estrus cycle,providing a scientific basis for the application of fish oil in animal production and human health.