LA Diet Research Articles

Diet high in linoleic acid dysregulates the intestinal endocannabinoid system and increases susceptibility to colitis in Mice

ABSTRACT Inflammatory bowel disease (IBD) is a multifactorial disease with increasing incidence in the U.S. suggesting that environmental factors, including diet, are involved. It has been suggested that excessive consumption of linoleic acid (LA, C18:2 omega-6), which must be obtained from the diet, may promote the development of IBD in humans. To demonstrate a causal link between LA and IBD, we show that a high fat diet (HFD) based on soybean oil (SO), which is comprised of ~55% LA, increases susceptibility to colitis in several models, including IBD-susceptible IL10 knockout mice. This effect was not observed with low-LA HFDs derived from genetically modified soybean oil or olive oil. The conventional SO HFD causes classical IBD symptoms including immune dysfunction, increased intestinal epithelial barrier permeability, and disruption of the balance of isoforms from the IBD susceptibility gene Hepatocyte Nuclear Factor 4α (HNF4α). The SO HFD causes gut dysbiosis, including increased abundance of an endogenous adherent invasive Escherichia coli (AIEC), which can use LA as a carbon source. Metabolomic analysis shows that in the mouse gut, even in the absence of bacteria, the presence of soybean oil increases levels of LA, oxylipins and prostaglandins. Many compounds in the endocannabinoid system, which are protective against IBD, are decreased by SO both in vivo and in vitro. These results indicate that a high LA diet increases susceptibility to colitis via microbial and host-initiated pathways involving alterations in the balance of bioactive metabolites of omega-6 and omega-3 polyunsaturated fatty acids, as well as HNF4α isoforms.

Effects of Microencapsulated Probiotics on Performance, Organ Development, Diarrhoea Incidences, Blood Parameters, Intestinal Histomorphology and Microflora in Weaning Piglets

The study aimed to assess the effects of the dietary supplementation of microencapsulated L. acidophilus and L. plantarum and their combination on the growth performance, organ development, diarrhoea incidences, blood profiles, intestinal histomorphology and microflora in weaned piglets. For that, 160 piglets with an average body weight (BW) of 8.52 ± 0.15 kg were divided into four groups (40 piglets/group) and allotted to one of the four dietary treatments as follows: a basal diet (C diet) or a basal diet containing 1 × 108 CFU/g of L. acidophilus (LA diet), or a diet containing 3 × 108 CFU/g of L. plantarum (LP diet) and a diet with the combination of both bacterial strains (LA + LP diet) for 21 days. On day 14, probiotics significantly increased ADFI, while FCR was higher in the LA and LP groups than the C and LA + LP groups. No effects (p > 0.05) on visceral organs weight, intestinal pH and biochemical parameters among treatments were noticed. Treatments significantly lowered diarrhoea incidence compared to control. Villus width was greater (p < 0.05) in all small intestinal segments in piglets fed probiotics. In the jejunum and ileum villus length, crypt length, and total villi length were higher (p < 0.05), particularly in the LA + LP group. The probiotics, particularly the LA + LP group, modulated the cecal, jejunum and ileum microbial community structure and increased (p < 0.05) the amount of Lactobacillus spp. while decreasing the populations of Escherichia coli and Staphylococcus. Our results indicated that dietary supplementation of microencapsulated probiotics, particularly the combination of L. plantarum and L acidophilus strains, maintained growth performance, lowered diarrhoea incidence and beneficially altered the intestinal architecture and microbial populations of weaned piglets.

Effects of Replacing Alfalfa Hay With Native Grass Hay in Pelleted Total Mixed Ration on Physicochemical Parameters, Fatty Acid Profile, and Rumen Microbiota in Lamb.

This study aimed to investigate the effects of replacing alfalfa with native grass on growth performance, meat quality, and rumen microbiota of lambs. Forty-five 6-month-old Ujimqin lambs with live body weight (BW) of 29.50 ± 0.26 kg were used for the experiment, and the lambs were assigned to three diet treatments (three pens per treatment and five lambs per pen) with 30 square meters per pen in semi-open housing based on similar BW. The lambs have received 30% alfalfa (HA, high alfalfa percentage group), 20% alfalfa (MA, moderate alfalfa percentage group), and 10% alfalfa (LA, low alfalfa percentage group) diets, respectively (dry matter basis). The diet treatments had a significant (P < 0.05) influence on the dry matter intake of lambs and the dry matter intake increased with the increasing percentages of native grass hay, while the significantly (P < 0.05) lower final BW and average daily gain were observed in the MA and LA groups compared with that in the HA group. The diet had a significant (P < 0.05) difference in meat pH value, water loss rate, cooked meat rate, moisture, and intramuscular fat, while no significant (P > 0.05) difference was found in protein. As native grass hay percentages increased in the diet, the contents of palmitic (C16:0) and palmitoleic (C16:1 cis-9) in the HA and MA groups were significantly (P < 0.05) lower than that in the LA groups, and compared with the HA group, the contents of elaidic (C18:1 trans-9), oleic (C18:1 cis-9), and linoleic (C18:2 cis-9–cis-12) were significantly (P < 0.05) increased in the MA and LA groups. The content of α-linolenic (C18:3n3) was significantly (P < 0.05) higher in the LA group than that in the HA and MA groups. The principal coordinate analysis profile displayed that the composition of the bacterial community of these groups was distinctly separated from each other. No significant (P > 0.05) difference was observed in the dominant rumen bacteria at the phyla and genus levels. In conclusion, the meat quality and fatty acid profile analysis revealed that replacing alfalfa hay with native grass hay is more beneficial for Mongolian lambs, and the meat from LA diet treatment is better than the others. In addition, correlation analysis of the association of rumen microbiome with growth performance, meat quality, and fatty acid profile provides us with a comprehensive understanding of the composition and function of rumen microbiota. These findings could provide knowledge of how the diet affects the animal performance, meat quality of lambs, and microbiota of the rumen, laying a theoretical basis for replacing alfalfa with native grass.

Estrogen Deficiency And Diet Differentially Regulate Goblet Cell Count And Inflammation In Gut

Estrogen is known to regulate many processes in women that protect them from inflammation prior to menopause. Upon menopause and estrogen deficiency, many women experience increased risk for inflammatory-based chronic diseases that can be comorbid with weight gain. Our lab has previously shown increased weight gain and increased intestinal inflammation in ovariectomized (OVX) animals. 4-Vinylcyclohexene dioxide (VCD) is an injectable chemical used to induce menopause and decrease estrogen production. However, the extent to which VCD is like OVX and how VCD may interact with high-fat diets is not well understood. PURPOSE: The purpose of this study was to investigate the effect of estrogen deficiency, via VCD injection, in animals fed diets that contains high (22.5%) and low (1%) amounts of omega-6 fatty acids (LA). METHODS: Forty 4-month old C57BL/6 J female mice were fed a chow diet and injected with either VCD or oil (control). After 4 weeks of injections, mice were fed either 22.5% or 1% LA diets for an additional 4 weeks until sacrifice, accounting for estrous phase. Colon samples were collected and preserved in 3% paraformaldehyde 2% sucrose solution for immunohistochemistry. Tissue staining included (1) Periodic acid-Schiff (PAS) to observe goblet cells and (2) the inflammatory marker cyclooxygenase-2 (COX-2). RESULTS: VCD-injections did not cause significant weight gain in either 22.5% (35.8 ± 2.6 vs 31.7 ± 1.5, p = 0.524; oil vs VCD) or 1% (36.7 ± 2.1 vs 33.2 ± 2.2, p = 0.670; oil vs VCD) LA groups. Mice consuming a 22.5% LA diet had a significantly higher number of goblet cells compared to VCD-injected mice on the same diet (18.0 ± 0.8 vs 13.0 ± 0.5, p = 0.001; oil vs VCD) or 1% LA group (8.4 ± 0.3, p < 0.001). COX-2 expression was highest in oil-injected 22.5% LA animals. CONCLUSION: VCD did not increase weight gain as normally seen with OVX. The 22.5% LA oil-injected animals had the highest inflammation and goblet cell counts. VCD injections did increased the number of goblet cells compared to control, independent of diet. While VCD animals did not have similar body weight changes as seen in OVX, we found that inflammation manifested a compensatory response in goblet cell count which may be an attempt to protect the gut lining from inflammation.

Low dietary protein increases vitamin A absorption and deposition into milk in periparturient rats.

Our objective was to study the effect of differing dietary crude protein and vitamin A on retinoid metabolism in a periparturient rat model. Sixty female rats, approximately 21 d before parturition, were fed rations containing either low protein (13%; LP) or high protein (22%; HP) crude protein and either low vitamin A (3IU/g; LA) or high vitamin A (5IU/g; HA), yielding treatments HPHA, HPLA, LPHA, and LPLA. Samples were collected at d -14, d +3, and +10 relative to parturition and analyzed for all-trans retinoid acid (RA), 13-Cis RA, and retinol. At d -14, serum all-trans RA concentrations decreased compared to baseline. At both d +3 and d +10, serum retinol increased and liver 13-Cis RA decreased. In the small intestine, 13-cis RA was higher in HPHA than HPLA pre-partum (0.93±0.12 vs. 0.40±0.12ng/ml, P=0.04). Post-partum, 13-cis RA was lower in high vitamin HPHA and LPHA groups (0.35±0.06 and 0.38±0.06ng/ml) than in low vitamin A HPLA and LPLA treatments (0.50±0.06 and 1.32±0.06ng/ml, P<0.01). In rats fed LA diets, TNF-alpha expression tended to be lower in HPLA than LPLA groups on day +3 (0.69±0.34 vs 1.00±0.52, P=0.08), but not day +10 (0.56±0.25 vs. 1.00±0.49 fold change, P>0.10). Retinoids accumulated during pregnancy and were mobilized during lactation. The sequestration of retinoids was increased when dietary protein content was low. Further studies are needed to investigate how retinoid metabolism could be manipulated to improve vitamin A delivery to milk.

Maternal diet high in linoleic acid alters offspring fatty acids and cardiovascular function in a rat model.

Linoleic acid (LA), an essential n-6 fatty acid (FA), is critical for fetal development. We investigated the effects of maternal high LA (HLA) diet on offspring cardiac development and its relationship to circulating FA and cardiovascular function in adolescent offspring, and the ability of the postnatal diet to reverse any adverse effects. Female Wistar Kyoto rats were fed low LA (LLA; 1·44 % energy from LA) or high LA (HLA; 6·21 % energy from LA) diets for 10 weeks before pregnancy and during gestation/lactation. Offspring, weaned at postnatal day 25, were fed LLA or HLA diets and euthanised at postnatal day 40 (n 6-8). Maternal HLA diet decreased circulating total cholesterol and HDL-cholesterol in females and decreased total plasma n-3 FA in males, while maternal and postnatal HLA diets decreased total plasma n-3 FA in females. α-Linolenic acid (ALA) and EPA were decreased by postnatal but not maternal HLA diets in both sexes. Maternal and postnatal HLA diets increased total plasma n-6 and LA, and a maternal HLA diet increased circulating leptin, in both male and female offspring. Maternal HLA decreased slopes of systolic and diastolic pressure-volume relationship (PVR), and increased cardiac Col1a1, Col3a1, Atp2a1 and Notch1 in males. Maternal and postnatal HLA diets left-shifted the diastolic PVR in female offspring. Coronary reactivity was altered in females, with differential effects on flow repayment after occlusion. Thus, maternal HLA diets impact lipids, FA and cardiac function in offspring, with postnatal diet modifying FA and cardiac function in the female offspring.

Effects of dietary incorporation of linseed oil with soybean isoflavone on fatty acid profiles and lipid metabolism-related gene expression in breast muscle of chickens

The meat quality of chicken is an important factor affecting the consumer’s health. It was hypothesized that n-3 polyunsaturated fatty acid (n-3 PUFA) could be effectively deposited in chicken, by incorporating antioxidation of soybean isoflavone (SI), which led to improved quality of chicken meat for good health of human beings. Effects of partial or complete dietary substitution of lard (LA) with linseed oil (LO), with or without SI on growth performance, biochemical indicators, meat quality, fatty acid profiles, lipid-related health indicators and gene expression of breast muscle were examined in chickens. A total of 900 males were fed a corn–soybean meal diet supplemented with 4% LA, 2% LA + 2% LO and 4% LO and the latter two including 30 mg SI/kg (2% LA + 2% LO + SI and 4% LO + SI) from 29 to 66 days of age; each of the five dietary treatments included six replicates of 30 birds. Compared with the 4% LA diet, dietary 4% LO significantly increased the feed efficiency and had no negative effect on objective indices related to meat quality; LO significantly decreased plasma triglycerides and total cholesterol (TCH); abdominal fat percentage was significantly decreased in birds fed the 4% LO and 4% LO + SI diets. Chickens with LO diets resulted in higher contents of α-linolenic acid (C18:3n-3), EPA (C20:5n-3) and total n-3 PUFA, together with a lower content of palmitic acid (C16:0), lignoceric acid (C24:0), saturated fatty acids and n-6:n-3 ratio in breast muscle compared to 4% LA diet (P < 0.05); they also significantly decreased atherogenic index, thrombogenic index and increased the hypocholesterolemic to hypercholesterolemic ratio. Adding SI to the LO diets enhanced the contents of EPA and DHA (C22:6n-3), plasma total superoxide dismutase, reduced glutathione (GSH)/oxidized glutathione and muscle GSH content, while decreased plasma total triglyceride and TCH and malondialdehyde content in plasma and breast muscle compared to its absence (P < 0.05). Expression in breast muscle of fatty acid desaturase 1 (FADS1), FADS2, elongase 2 (ELOVL2) and ELOVL5 genes were significantly higher with the LO diets including SI than with the 4% LA diet. Significant interactions existed between LO level and inclusion of SI on EPA and TCH contents. These findings indicate that diet supplemented with LO combined with SI is an effective alternative when optimizing the nutritional value of chicken meat for human consumers.

Expression of cholesterol packaging and transport genes in human and rat placenta: impact of obesity and a high-fat diet.

Evidence suggests that sub-optimal maternal nutrition has implications for the developing offspring. We have previously shown that exposure to a low-protein diet during gestation was associated with upregulation of genes associated with cholesterol transport and packaging within the placenta. This study aimed to elucidate the effect of altering maternal dietary linoleic acid (LA; omega-6) to alpha-linolenic acid (ALA; omega-6) ratios as well as total fat content on placental expression of genes associated with cholesterol transport. The potential for maternal body mass index (BMI) to be associated with expression of these genes in human placental samples was also evaluated. Placentas were collected from 24 Wistar rats at 20-day gestation (term = 21-22-day gestation) that had been fed one of four diets containing varying fatty acid compositions during pregnancy, and from 62 women at the time of delivery. Expression of 14 placental genes associated with cholesterol packaging and transfer was assessed in rodent and human samples by quantitative real time polymerase chain reaction. In rats, placental mRNA expression of ApoA2, ApoC2, Cubn, Fgg, Mttp and Ttr was significantly elevated (3-30 fold) in animals fed a high LA (36% fat) diet, suggesting increased cholesterol transport across the placenta in this group. In women, maternal BMI was associated with fewer inconsistent alterations in gene expression. In summary, sub-optimal maternal nutrition is associated with alterations in the expression of genes associated with cholesterol transport in a rat model. This may contribute to altered fetal development and potentially programme disease risk in later life. Further investigation of human placenta in response to specific dietary interventions is required.

Linoleic acid in diets of mice increases total endocannabinoid levels in bowel and liver: modification by dietary glucose.

SummaryAimLinoleic acid (LA) is an essential fatty acid involved in the biosynthesis of arachidonic acid and prostaglandins. LA is known to induce obesity and insulin resistance. In this study, two concentrations of LA with or without added glucose (G) were fed to mice to investigate their effects on endocannabinoid (EC) biology.Materials and MethodsFour groups of C57BL/6 mice were provided with diets containing 1% or 8% LA with or without added G (LAG) for 8 weeks. Body weights, food intake, circulating glucose and insulin levels were measured throughout the study. Following euthanasia, plasma, bowel and hepatic ECs, monoacylglycerol lipase and fatty acid amide hydroxylase protein levels (enzymes responsible for EC degradation) and transcriptional activity of PPARα in liver were quantified. Liver was probed for evidence of insulin receptor activity perturbation.ResultsIncreasing dietary LA from 1% to 8% significantly increased circulating, small bowel and hepatic ECs. 1%LAG fed mice had lowest feed efficiency, and only liver levels of both ECs were reduced by addition of G. Addition of G to 1% LA diets resulted in elevated monoacylglycerol lipase and fatty acid amide hydroxylase protein levels (p < 0.001 and p < 0.001, respectively) in liver due to increased transcriptional activity of PPARα (p < 0.05). The reduced EC levels with addition of G also correlated with a measure of enhanced insulin action.ConclusionIn conclusion, body weight of mice is influenced by the source of calorie intake. Furthermore, tissue EC/g are dependent on tissue‐specific synthesis and degradation that are modulated by dietary LA and G which also influence food efficiency, and down‐stream insulin signalling pathways. The findings could potentially be useful information for weight management efforts in humans.

The comparisons in protective mechanisms and efficiencies among dietary α-lipoic acid, β-glucan and l-carnitine on Nile tilapia infected by Aeromonas hydrophila

Dietary α-lipoic acid (LA), β-glucan (Gluc) and l-carnitine (L-Ca) are commonly used additives to promote fish growth and stress resistance in aquaculture production. However their mechanisms and efficiencies in helping fish to resist diseases have not been compared before. In this study, we fed Nile tilapia (Oreochromis niloticus) with diets containing appropriate doses of LA, Gluc and L-Ca for five weeks and further intraperitoneally injected the fish with Aeromonas hydrophila. After dietary treatment, none of the additives affected the fish growth, but dietary Gluc and L-Ca reduced protein and lipid body contents in fish, respectively. After A. hydrophila challenge, all fish treated with the three dietary additives showed higher survival rate, but those fed on dietary L-Ca had lower survival than those fed on LA and Gluc diets, indicating high protection efficiency of LA and Gluc. The protective mechanisms of the three feed additives were quite different under A. hydrophila infection. Dietary LA induced higher total antioxidant capacity and higher mRNA expression of anti-oxidative genes than other additives in liver and also activated partly the immune function in serum and spleen. Gluc largely increased the immune function by activating the immunity enzymes in serum, inducing inflammation in liver and increasing the expression of immune genes in spleen and head kidney. Gluc also increased partly the antioxidant capacity in serum and liver and lipid catabolism in liver. L-Ca largely increased lipid catabolism in liver while it increased partly the antioxidant capacities in serum and liver. Taken together, these results indicate that, dietary LA, Gluc and L-Ca have various protective mechanisms and differ in their efficiencies on resisting A. hydrophila infection in Nile tilapia.

Proteomic Analysis of the Hepatopancreas of Chinese Mitten Crabs (Eriocheir sinensis) Fed With a Linoleic Acid or α-Linolenic Acid Diet.

As representatives of n-6 and n-3 fatty acids, many studies have analyzed the use of soybean oil and linseed oil rich in linoleic acid (18:2n-6, LA) and α-linolenic acid (18:3n-3, LNA) as better substitutes for fish oil. In aquatic animals, different dietary ratios of LA and LNA could have significant effects on growth, lipid metabolism, immune response, and reproduction. To assess the nutritive value of these two fatty acids in Chinese mitten crab (Eriocheir sinensis), we performed transcriptome analysis and label-free quantification proteomic analysis of the hepatopancreas from mitten crabs fed with LA or LNA diet. Parallel reaction monitoring was used to confirm the reliability of the proteomic analysis. A total of 186 proteins were differentially expressed with fold change ≥1.5 or ≤0.666. Among the 186 proteins, 116 were upregulated and 70 were downregulated in the LA than LNA. Most of these proteins participate in cellular process and metabolism process and have molecular functions such as binding and catalytic activity; the cellular component of these proteins are cell, cell part, membrane, and membrane part. A total of 18 proteins were identified to be related to lipid, carbohydrate, and protein metabolism, and they mainly participate in digestive enzyme activities, fatty acid transport, and glycolysis. Our results provide new insights for further investigation into the replacement of fish oil from mitten crabs with vegetable oils and enable us to better understand the different roles and nutrition value of LA and LNA in mitten crabs.

Effects of diets enriched in linoleic acid and its peroxidation products on brain fatty acids, oxylipins, and aldehydes in mice

BackgroundLinoleic acid (LA) is abundant in modern industrialized diets. Oxidized LA metabolites (OXLAMs) and reactive aldehydes, such as 4-hydroxy-2-nonenal (4-HNE), are present in heated vegetable oils and can be endogenously synthesized following consumption of dietary LA. OXLAMs have been implicated in cerebellar degeneration in chicks; 4-HNE is linked to neurodegenerative conditions in mammals. It unknown whether increasing dietary LA or OXLAMs alters the levels of oxidized fatty acids (oxylipins), precursor fatty acids, or 4-HNE in mammalian brain. ObjectivesTo determine the effects of increases in dietary OXLAMs and dietary LA, on levels of fatty acids, oxylipins, and 4-HNE in mouse brain tissues. MethodsMice (n = 8 per group) were fed one of three controlled diets for 8 weeks: (1) a low LA diet, (2) a high LA diet, or (3) the low LA diet with added OXLAMs. Brain fatty acids, oxylipins, and 4-HNE were quantified in mouse cerebellum and cerebral cortex by gas chromatography-flame ionization detection, liquid chromatography-tandem mass spectrometry, and immunoblot, respectively. ResultsIncreasing dietary LA significantly increased omega-6 fatty acids, decreased omega-3 fatty acids, and increased OXLAMs in brain. Dietary OXLAMs had minimal effect on oxidized lipids but did decrease both omega-6 and omega-3 fatty acids. Neither dietary LA nor OXLAMs altered 4-HNE levels. ConclusionBrain fatty acids are modulated by both dietary LA and OXLAMs, while brain OXLAMs are regulated by endogenous synthesis from LA, rather than incorporation of preformed OXLAMs.

The effect of alfalfa (Medicago sativa) silage chop length and inclusion rate within a total mixed ration on the ability of lactating dairy cows to cope with a short-term feed withholding and refeeding challenge

The objectives of the study were (1) to test whether 6 h of feed deprivation followed by refeeding induces an acidosis challenge in dairy cattle and (2) to quantify the acidosis challenge mitigation potential of increased alfalfa silage concentration in the diet. Alfalfa silage constituted either 25 or 75% of forage dry matter (DM) replacing corn silage [low (LA) or high alfalfa (HA)] and was chopped to either 14 or 19 mm theoretical length [short (S) or long (L)]. Dietary treatments LAS, LAL, HAS, or HAL were offered to 4 rumen-cannulated Holstein dairy cattle (161 d in milk; 5th or 6th parity) in a 4 × 4 Latin square design study with 21-d periods. Starch concentration was 69 g/kg of DM higher for LA diets than HA diets. Feed was withheld for 6 h followed by ad libitum refeeding on d 18 of each period. Measurements of DM intake, milk yield and composition, rumen pH, and eating and rumination behavior were taken on 1 baseline day, the challenge day, and 2 further recovery days. After refeeding, rumen pH was reduced in cows fed LA diets but not HA diets. Feeding LAL resulted in the greatest subclinical acidosis risk (pH <5.8 for 355 min on the first recovery day). Animals fed LA produced 4.4 L less milk on the challenge day in comparison to baseline. It was concluded that short-term feed deprivation detrimentally affected rumen health and milk yield in dairy cattle normally fed ad libitum, but had no effect on DM intake or milk composition. Feeding alfalfa silage in place of corn silage mitigated acidosis risk due to interrupted feed supply, likely due to a combination of lower starch concentration in HA diets, greater effective fiber concentration, and higher buffering capacity of alfalfa relative to corn silage.

Interactive effects of dietary arginine and Eimeria acervulina infection on broiler growth performance and metabolism

The influence of dietary Arg concentration and Eimeria acervulina infection on broiler growth performance and plasma carotenoid, nitric oxide (NO), amino acid, and urea concentrations was evaluated. Male Ross × Ross 308 broilers (384 total) were fed a common diet for 10 d post-hatch and provided experimental diets formulated to contain 1.23 (HA) or 0.74% (LA) standardized ileal digestible Arg from 10 to 28 d. At 21 d, one-half of the broilers were switched to the opposite diet to create 4 dietary regimens where birds were fed the LA diet throughout, the LA diet replaced by the HA diet at 21 d, the HA diet throughout, or the HA diet replaced by the LA diet at 21 d. Broilers were orally inoculated 0 (uninfected) or 3.5 × 105 sporulated E. acervulina oocysts at 15 d, resulting in a factorial arrangement of 4 dietary regimens × 2 infection states (8 replicates/treatment). Overall (10 to 28 d) BW gain and G:F were greatest (P < 0.01) for birds fed the HA diet throughout, regardless of infection status. Eimeria acervulina infection decreased (P < 0.01) BW gain of birds from 15 to 21 d, and G:F was lowest (P < 0.05) for infected birds fed the LA diet during this period. There was no influence (P > 0.05) of E. acervulina on BW gain or G:F of broilers from 21 to 28 d. Plasma Arg, Lys, and Orn levels at 21 d indicated that the LA diet caused an imbalance in the Lys and Arg status of broilers, and E. acervulina infection increased (P < 0.01) the plasma concentration of these 3 amino acids. Diet × infection interactions (P < 0.05) were observed on 21 d for plasma carotenoids and NO, whereby infection decreased plasma carotenoids and increased plasma NO, but dietary Arg concentration only influenced these measures for uninfected birds. Thus, production of NO during E. acervulina infection was not impaired by dietary Arg limitation.

Changes in in vitro gas and methane production from rumen fluid from dairy cows during adaptation to feed additives in vivo

The adaptation of dairy cows to methane (CH4)-mitigating feed additives was evaluated using the in vitro gas production (GP) technique. Nine rumen-fistulated lactating Holstein cows were grouped into three blocks and within blocks randomly assigned to one of three experimental diets: Control (CON; no feed additive), Agolin RuminantR (AR; 0.05 g/kg dry matter (DM)) or lauric acid (LA; 30 g/kg DM). Total mixed rations composed of maize silage, grass silage and concentrate were fed in a 40 : 30 : 30 ratio on DM basis. Rumen fluid was collected from each cow at days −4, 1, 4, 8, 15 and 22 relative to the introduction of the additives in the diets. On each of these days, a 48-h GP experiment was performed in which rumen fluid from each individual donor cow was incubated with each of the three substrates that reflected the treatment diets offered to the cows. DM intake was on average 19.8, 20.1 and 16.2 kg/day with an average fat- and protein-corrected milk production of 30.7, 31.7 and 26.2 kg/day with diet CON, AR and LA, respectively. In general, feed additives in the donor cow diet had a larger effect on gas and CH4 production than the same additives in the incubation substrate. Incubation substrate affected asymptotic GP, half-time of asymptotic CH4 production, total volatile fatty acid (VFA) concentration, molar proportions of propionate and butyrate and degradation of organic matter (OMD), but did not affect CH4 production. No substrate×day interactions were observed. A significant diet×day interaction was observed for in vitro gas and CH4 production, total VFA concentration, molar proportions of VFA and OMD. From day 4 onwards, the LA diet persistently reduced gas and CH4 production, total VFA concentration, acetate molar proportion and OMD, and increased propionate molar proportion. In vitro CH4 production was reduced by the AR diet on day 8, but not on days 15 and 22. In line with these findings, the molar proportion of propionate in fermentation fluid was greater, and that of acetate smaller, for the AR diet than for the CON diet on day 8, but not on days 15 and 22. Overall, the data indicate a short-term effect of AR on CH4 production, whereas the CH4-mitigating effect of LA persisted.

Dietary Linoleic Acid Lowering Reduces Lipopolysaccharide-Induced Increase in Brain Arachidonic Acid Metabolism.

Linoleic acid (LA, 18:2n-6) is a precursor to arachidonic acid (AA, 20:4n-6), which can be converted by brain lipoxygenase and cyclooxygenase (COX) enzymes into various lipid mediators involved in the regulation of brain immunity. Brain AA metabolism is activated in rodents by the bacterial endotoxin, lipopolysaccharide (LPS). This study tested the hypothesis that dietary LA lowering, which limits plasma supply of AA to the brain, reduces LPS-induced upregulation in brain AA metabolism. Male Fischer CDF344 rats fed an adequate LA (5.2% energy (en)) or low LA (0.4% en) diet for 15weeks were infused with LPS (250ng/h) or vehicle into the fourth ventricle for 2days using a mini-osmotic pump. The incorporation rate of intravenously infused unesterified 14C-AA into brain lipids, eicosanoids, and activities of phospholipase A2 and COX-1 and 2 enzymes were measured. Dietary LA lowering reduced the LPS-induced increase in prostaglandin E2 concentration and COX-2 activity (P < 0.05 by two-way ANOVA)without altering phospholipase activity. The 14C-AA incorporation rate into brain lipids was decreased by dietary LA lowering (P < 0.05 by two-way ANOVA). The present findings suggest that dietary LA lowering reduced LPS-induced increase in brain markers of AA metabolism. The clinical utility of LA lowering in brain disorders should be exploredin future studies.

Regulation of rat plasma and cerebral cortex oxylipin concentrations with increasing levels of dietary linoleic acid

Linoleic acid (LA, 18:2n-6) is the most abundant polyunsaturated fatty acid in the North American diet and is a precursor to circulating bioactive fatty acid metabolites implicated in brain disorders. This exploratory study tested the effects of increasing dietary LA on plasma and cerebral cortex metabolites derived from LA, its elongation-desaturation products dihomo-gamma linolenic (DGLA, 20:3n-6) acid and arachidonic acid (AA, 20:4n-6), as well as omega-3 alpha-linolenic (α-LNA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3). Plasma and cortex were obtained from rats fed a 0.4%, 5.2% or 10.5% energy LA diet for 15 weeks and subjected to liquid chromatography tandem mass spectrometry analysis. Total oxylipin concentrations, representing the esterified and unesterified pool, and unesterified oxylipins derived from LA and AA were significantly increased and EPA metabolites decreased in plasma at 5.2% or 10.5% energy LA compared to 0.4% energy LA. Unesterified plasma DHA metabolites also decreased at 10.5% energy LA. In cortex, total and unesterified LA and AA metabolites increased and unesterified EPA metabolites decreased at 5.2% or 10.5% LA. DGLA and α-LNA metabolites did not significantly change in plasma or cortex. Dietary LA lowering represents a feasible approach for targeting plasma and brain LA, AA, EPA or DHA-derived metabolite concentrations.

Effects of probiotic supplement (Bacillus subtilis and Lactobacillus acidophilus) on feed efficiency, growth performance, and microbial population of weaning rabbits.

ObjectiveThis study aimed to investigate the effects of single or/and double strains of probiotic supplement on feed efficiency, growth performance, and microbial population in distal gastrointestinal tract (GIT) of weaning rabbits.MethodsSixty-four weaning (28 days old) New Zealand White rabbits were randomly distributed into four groups with treatments including: basal diet without probiotic supplement (control) or supplemented as follows: 1×106 cfu/g B. subtilis (BS group), 1×107 cfu/g L. acidophilus (LA group), or 0.5×106 cfu/g B. subtilis plus 0.5×107 cfu/g L. acidophilus (BL group). During the research, the male and female rabbits were fed separately. Body weight of the rabbits was recorded at 28, 42, and 70 d of age.ResultsThere was an increase (p<0.05) in body weight gain for the LA group at 42 d. Rabbits fed BL responsed with a greater growth (p<0.05) and better feed conversion ratio (p<0.05) than those fed with no probiotic. Digestibility coefficients of dry matter, organic matter, crude protein, neutral detergent fiber, and gross energy were higher (p<0.05) in LA and BL groups than those in the control group. Male rabbits had higher (p<0.05) Bacilli spp. and Coliformis spp. in the ileum than female rabbits. Rabbits supplemented with BS had greater (p<0.05) numbers of bacilli in all intestinal segments than those receiving no probiotic, whereas intestinal Lactobacilli populations were greater (p<0.001) in the LA and BL diets compared to control. Average intestinal coliform populations were lowest (p<0.05) in the rabbits supplemented with LA as compared to those fed the control and BS.ConclusionSupplementation of L. acidophilus alone or in combination with B. subtilis at a half of dose could enhance number of gut beneficial bacteria populations, nutrient digestibility, cecal fermentation, feed efficiency, and growth performance, but rabbits receiving only B. subtilis alone were not different from the controls without probiotic.

Transcriptome analysis in calorie-restricted rats implicates epigenetic and post-translational mechanisms in neuroprotection and aging.

BackgroundCaloric restriction (CR) can increase longevity in rodents and improve memory function in humans. α-Lipoic acid (LA) has been shown to improve memory function in rats, but not longevity. While studies have looked at survival in rodents after switching from one diet to another, the underlying mechanisms of the beneficial effects of CR and LA supplementation are unknown. Here, we use RNA-seq in cerebral cortex from rats subjected to CR and LA-supplemented rats to understand how changes in diet can affect aging, neurodegeneration and longevity.ResultsGene expression changes during aging in ad libitum-fed rats are largely prevented by CR, and neuroprotective genes are overexpressed in response to both CR and LA diets with a strong overlap of differentially expressed genes between the two diets. Moreover, a number of genes are differentially expressed specifically in rat cohorts exhibiting diet-induced life extension. Finally, we observe that LA supplementation inhibits histone deacetylase (HDAC) protein activity in vitro in rat astrocytes. We find a single microRNA, miR-98-3p, that is overexpressed during CR feeding and LA dietary supplementation; this microRNA alters HDAC and histone acetyltransferase (HAT) activity, which suggests a role for HAT/HDAC homeostasis in neuroprotection.ConclusionsThis study presents extensive data on the effects of diet and aging on the cerebral cortex transcriptome, and also emphasises the importance of epigenetics and post-translational modifications in longevity and neuroprotection.Electronic supplementary materialThe online version of this article (doi:10.1186/s13059-015-0847-2) contains supplementary material, which is available to authorized users.

Additive effects of dietary glycotoxins and androgen excess on the kidney of a female rat model

BackgroundDietary glycotoxins and androgen excess have been independently associated with a negative influence on the kidney. There are no data concerning the additive effects of these two factors on the kidney function and structure, in females. The present study aims to investigate the effect of dietary glycotoxins and androgen excess on the kidneys of an androgenized female rat model. MethodsThe study involved 80 female Wistar rats divided into 3 groups. The animals from group A were androgenized at 4weeks of age (n=30), rats of group B were androgenized at 12–20weeks of age (n=20) and group C consisted of non-androgenized animals (n=30). All groups were further randomly assigned, either to a high-Advanced Glycation End product diet (HA diet) or low-AGE diet (LA diet), for 3months. ResultsThe rats fed with HA diet had significantly higher serum creatinine levels (p⩽0.0002), when compared with those fed with LA diet. The androgenized group fed with HA diet exhibited higher levels of serum AGE (p=0.0005), creatinine levels (p<0.0001) and C-reactive protein (CRP) levels (p⩽0.002), when compared with the non-androgenized group fed with HA diet. AGE immunoreactivity was higher on the renal tubules of the androgenized animals fed with HA diet, when compared with the animals fed with LA diet, but did not significantly differ among the two groups. ConclusionsThe above mentioned data suggest that dietary glycotoxins, in combination with increased androgen exposure, exert a more profound negative impact on the kidney of an androgenized female rat model that mimics the metabolic characteristics of polycystic ovary syndrome.