High-starch Diet Research Articles

Supplementing a Clay Mineral-Based Feed Additive Modulated Fecal Microbiota Composition, Liver Health, and Lipid Serum Metabolome in Dairy Cows Fed Starch-Rich Diets.

Starch-rich diets are a commonly adopted strategy in order to sustain high milk yields in dairy cows. However, these diets are known to increase the risk of gut dysbiosis and related systemic health disorders. This study aimed to evaluate the effects of supplementing a clay mineral-based feed additive (CM; Mycofix® Plus, BIOMIN) on fecal microbiota structure, fecal short-chain fatty acid (SCFA) fermentation, serum metabolome, and liver health in primiparous (PP, n = 8) and multiparous (MP, n = 16) early-lactation Simmental cows (737 ± 90 kg of live body weight). Cows were randomly assigned to either a control or CM group (55 g per cow and day) and transitioned from a diet moderate in starch (26.3 ± 1.0%) to a high starch diet (32.0 ± 0.8%). Supplementation of CM reversed the decrease in bacterial diversity, richness, and evenness (p < 0.05) during high-starch diet, demonstrating that CM supplementation efficiently eased hindgut dysbiosis. The CM treatment reduced levels of Lactobacillus in PP cows during starch-rich feeding and elevated fecal pH, indicating a healthier hindgut milieu compared with that in control. Butyrate and propionate levels were modulated by CM supplementation, with butyrate being lower in CM-treated MP cows, whereas propionate was lower in MP but higher in PP cows. Supplementing CM during high-starch feeding increased the concentrations of the main primary bile salts and secondary bile acids in the serum and improved liver function in cows as indicated by reduced levels of glutamate dehydrogenase and γ-glutamyl-transferase, as well as higher serum albumin and triglyceride concentrations. These changes and those related to lipid serum metabolome were more pronounced in PP cows as also corroborated by relevance network analysis.

320 Liver Transcriptome Analysis Reveals Important Genes Involved in the Feed Efficiency of Lactating Cows Fed a High and Low Starch Diet

Abstract The objectives of this study were to identify different gene expression and metabolic pathways in the liver associated with feed efficiency of lactating cows fed high or low starch diets. Ten lactating cows were involved in a cross-over design experiment consisting of two 56-d treatment periods with 11-d diet adaptation fed either high starch (HS; 27% starch) or low starch (LS; 13% starch) diets. Feed efficiency, measured by residual feed intake (RFI), was estimated based on the difference between observed and expected metabolizable energy intake within each experimental period. The 3 highest RFI cows were considered high RFI (HRFI), the 3 lowest RFI cows were considered low (LRFI), and the remaining 4 cows were considered medium (MRFI) in each experimental period. Total RNA was used for next-generation RNA sequencing analysis. Raw reads were mapped to the cattle genome (UMD3.1) using STAR. Differential gene expression analysis was done using Cufflinks. We discovered 642 differentially expressed genes (DEGs) between HS and LS (FDR&amp;lt; 0.05) with 240 genes upregulated and 402 genes downregulated for HS versus LS diet. Via gene-set enrichment analysis (GSEA) analysis (FDR&amp;lt; 0.05), these genes were enriched in 25 gene ontology (GO) pathways related to mitochondria components and 4 GO biological processes involved in peptide metabolism. There were 1427 DEGs impacted by RFI (FDR&amp;lt; 0.05), of which 829 were upregulated, and 598 were downregulated in LRFI compared to HRFI. The 6 GO biological processes enriched by these genes were mainly related to organic substrate metabolism processing and carbon metabolism (FDR&amp;lt; 0.05). Between the DEGs affected by diet and RFI, 522 DGEs were unique to diet and 1307 DEGs were unique to RFI. Our results suggested that genes contributing to different RFIs and the ones associated with the dietary starch treatment may impact distinct pathways. Further functional annotation of these genes may improve feed efficiency.

Effects of dietary starch content and body condition score at calving on reproductive parameters in Holstein dairy cows

Nutritional modifications can potentially impact the reproductive performance and ultimately the economic results of dairy herds. The objectives were to investigate the effects of feeding a high starch (HS) diet and body condition score (BCS) at calving on reproductive responses and uterine health in Holstein dairy cows. One hundred seventy-four multiparous cows were randomly assigned to 1 of 2 experimental diets from 16 until 50 days in milk (DIM; n = 87 per group); normal starch (228 g/kg diet DM; NS) or high starch (270 g/kg diet DM; HS) diets. Each dietary treatment group was further subdivided based on BCS at calving as normal BCS (BCS ≤ 3.5; NBCS; n = 45) and high BCS (BCS ≥ 3.75; HBCS; n = 42). Transrectal ultrasonography was carried out at 10 DIM, and thereafter twice weekly until the onset of ovarian cyclicity or d 50 DIM. Feeding HS diet significantly affected the proportion of cows cycling by 30 and 40 DIM. Number of services per conception and calving interval (CI) were significantly improved in cows fed the HS compared to the NS diet (2.08 vs. 2.51 and 427.14 vs. 445.30 days for cows fed HS and NS diets, respectively). In summary, feeding higher starch diets from 16 till 50 DIM could be an effective strategy to improve the economic variables related to reproduction in dairy cows.

A High Starch Diet Alters the Composition of the Intestinal Microbiota of Largemouth Bass Micropterus salmoides, Which May Be Associated With the Development of Enteritis.

Starch is an inexpensive feed ingredient that has been widely used in fish feed. However, starch utilization by carnivorous fish is limited and excess starch is detrimental to the health of the organism. High starch diets often lead to liver damage, but the effects on the intestine are often overlooked. Therefore, in this study, two isonitrogenous and isolipidic semi-pure diets (NC: 0% α-starch, HC: 22% α-starch) were formulated and fed to largemouth bass (Micropterus salmoides) for 45 days. The effects of the high starch diet on the intestine of largemouth bass were comprehensively investigated by intestinal microbiota, histopathology, ultrastructural pathology, and enzymology analyses. Feeding the HC diet did not affect the growth of largemouth bass during the experimental period. However, the high starch diet led to a reduction in the diversity and abundance of intestinal microbiota in largemouth bass, with a significant increase in the abundance of harmful bacteria (Aeromonas) and a decrease in the abundance of beneficial bacteria (Clostridium, Lactobacillus, and Bifidobacterium). Feeding the HC diet caused the development of enteritis, with goblet cell hyperplasia, epithelial necrosis and detachment and inflammatory cell infiltration, and leading to enlarged apical openings and mitochondrial damage in goblet cells. Long-term feeding of the HC diet inhibited intestinal α-amylase activity. changes in the intestinal microbiota, such as an increase in Aeromonas and a decrease in Clostridium, Lactobacillus, and Bifidobacterium, may be closely related to the development of enteritis. Therefore, adding these beneficial bacteria as probiotics may be an effective way to prevent damage to the intestine of largemouth bass from a high carbohydrate diet. Our results suggest reducing the amount of starch added to the largemouth bass diets. This study provides a reference for protecting the largemouth bass gut during modern intensive culture.

Mulberry leaf powder ameliorate high starch-induced hepatic oxidative stress and inflammation in fish model

This study aimed to explore the effects of mulberry leaf powder on glucose metabolism as well as the underlying mechanisms. The largemouth bass (initial body weight: 10.12 ± 0.06 g) were randomly allotted into three treatments, fed low-starch diet (LS, 5%), high-starch diet (HS, 15 %) and high-starch diet with mulberry leaf powder (SM, 50 g/kg diet) for 8 weeks, respectively. Biochemistry parameters were tested using commercial biochemical kits, immune and antioxidant related genes expression were assessed using Q-PCR.The SM group exhibited significantly higher specific growth rate (SGR) and protein efficiency ratio (PER), and lower hepatosomatic index (HSI), liver lipid and glycogen contents than HS treatment. Simultaneously, the suppressed growth accompanied by impaired liver function was found in fish fed the HS diet compared to the LS group. However, supplementation with mulberry leaf diet (SM) significantly reduced plasma glucose, triglyceride (TG) and total cholesterol (TC) contents, the activities of alanine aminotransferase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) compared with the HS group. Accordingly, the liver histological investigation showed an improvement of liver histostructure in the SM group. Furthermore, hepatic SOD and CAT were significantly up-regulated by SM supplementation. Meanwhile, the superoxide dismutase (SOD) and catalase (CAT) activities of SM group were significantly increased, while malondialdehyde (MDA) content significantly reduced in liver compared with the HS group. In addition, SM supplementation significantly down-regulated the expression levels of nf-kb, tnf-a and il-8 in the liver, while il-10 showed significant improvement in the LS group compared to the HS group. Mulberry leaves could alleviate hepatic injuries by regulating inflammation and oxidative stress, providing a theoretical basis for the development of mulberry leaves as a drug against high starch-induced liver disease.

Feeding diets varying in starch concentration supplemented with palmitic acid or stearic acid: Effects on performance, milk fatty acid profile, and metabolic parameters of postpartum dairy cows

The objective of this study was to investigate the effects of dietary fat supplement rich in palmitic acid or stearic acid on milk yield and composition, fatty acid profile, energy partitioning, and metabolic parameters of dairy cows fed low or high starch diets from d 1 to 28 of the postpartum period. Forty-four multiparous Holstein cows were used in a complete randomized block (based on parity, and previous 305-d milk yield); 2 × 2 arrangement with two dietary starch levels [high starch (HS); 260 g/kg of diet dry matter (DM) versus low starch (LS); 210 g/kg of diet DM] with either palmitic acid (PA) or stearic acid (SA) supplementation at the level of 15 g/kg of diet DM. A basal close-up diet (6.19 MJ/kg of diet DM, NEL; 200 g/kg starch) was fed to animals prior to calving. Regardless of the fatty acid (FA) type, cows fed HS diets had a higher dry matter and NEL intake, milk protein and lactose content, and a more positive energy balance than cows fed LS diets during the postpartum period. Compared with HS diets, LS diets reduced energy toward body reserves and maintenance as a fraction of the NEL intake. Although there was no main effect of PA or SA supplement on intake and energy balance, the effect of fat supplementation depended on dietary starch levels for milk yields and milk energy as a fraction of the NEL intake. Stearic acid increased milk yield in HS diets while PA tended to increase yield in LS diets. Supplementation of PA partitioned less energy toward milk (and more energy for maintenance) in HS diets than LS diets. Moreover, the C16:0 FA concentration in milk fat was higher, and the polyunsaturated FA (PUFA) and C18:1 cis-9 FA were lower in PA supplemented cows fed HS diets but not cows fed LS diets. High starch rations increased de novo FA concentrations in milk and decreased C18:0 and preformed FA concentrations compared with LS diets. Also, HS diets tended to have higher levels of insulin and lower levels of beta-hydroxybutyrate (BHBA) than LS diets. In conclusion, the HS diet was more beneficial to improving the energy balance (EB) of dairy cows than LS diets during the early postpartum period. Also, interactions between dietary starch levels and FA supplement for the variables measured in the current study (e.g. milk yield or FA profile) indicate that the response to fat supplements rich in specific FA differed on the basis of dietary starch concentrations.

A Metagenomic Insight Into the Hindgut Microbiota and Their Metabolites for Dairy Goats Fed Different Rumen Degradable Starch.

High starch diets have been proven to increase the risk of hindgut acidosis in high-yielding dairy animals. As an effective measurement of dietary carbohydrate for ruminants, studies on rumen degradable starch (RDS) and the effects on the gut microbiota diversity of carbohydrate-active enzymes (CAZymes), and Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthology functional categories are helpful to understand the mechanisms between gut microbiota and carbohydrate metabolism in dairy goats. A total of 18 lactating goats (45.8 ± 1.54 kg) were randomly divided equally into three dietary treatments with low dietary RDS concentrations of 20.52% (LRDS), medium RDS of 22.15% (MRDS), and high RDS of 24.88% (HRDS) on a DM basis for 5 weeks. Compared with the LRDS and MRDS groups, HRDS increased acetate molar proportion in the cecum. For the HRDS group, the abundance of family Ruminococcaceae and genus Ruminococcaceae UCG-010 were significantly increased in the cecum. For the LRDS group, the butyrate molar proportion and the abundance of butyrate producer family Bacteroidale_S24-7, family Lachnospiraceae, and genus Bacteroidale_S24-7_group were significantly increased in the cecum. Based on the BugBase phenotypic prediction, the microbial oxidative stress tolerant and decreased potentially pathogenic in the LRDS group were increased in the cecum compared with the HRDS group. A metagenomic study on cecal bacteria revealed that dietary RDS level could affect carbohydrate metabolism by increasing the glycoside hydrolase 95 (GH95) family and cellulase enzyme (EC 3.2.1.4) in the HRDS group; increasing the GH13_20 family and isoamylase enzyme (EC 3.2.1.68) in the LRDS group. PROBIO probiotics database showed the relative gene abundance of cecal probiotics significantly decreased in the HRDS group. Furthermore, goats fed the HRDS diet had a lower protein expression of Muc2, and greater expression RNA of interleukin-1β and secretory immunoglobulin A in cecal mucosa than did goats fed the LRDS diet. Combined with the information from previous results from rumen, dietary RDS level altered the degradation position of carbohydrates in the gastrointestinal (GI) tract and increased the relative abundance of gene encoded enzymes degrading cellulose in the HRDS group in the cecum of dairy goats. This study revealed that the HRDS diet could bring disturbances to the microbial communities network containing taxa of the Lachnospiraceae and Ruminococcaceae and damage the mucus layer and inflammation in the cecum of dairy goats.

Spotted seabass, Lateolabrax maculatus can utilize the high-starch diet by effectively regulating the energy metabolism

Carbohydrates are the least cost feed source and conserve protein without affecting the growth of fish at a certain level. However, carnivorous fish fed with trophic levels >3.5 have a limited capability to utilize carbohydrates as an energy source. A 56-day feeding trial was conducted to evaluate the growth performance, hepatic histology, and glucose and lipid metabolism of spotted seabass, Lateolabrax maculatus (initial weight = 10.43 ± 0.01 g), a typical carnivorous fish, fed low - (130 g/kg) or high - starch (202 g/kg) diets (named the LS or HS diets) under satiety and starvation conditions (3 h and 24 h postprandial). The results showed that compared with the LS diet, the HS diet did not negatively affect growth but slightly increased the FR and FCR of spotted seabass. A well-regulated glucose metabolism response was observed in the HS group with significant downregulation of gluconeogenesis (G6P) and upregulation of glycolysis (PK) at 3 h postprandial (P3 h) and downregulation of glycolysis (GK, PFK-1) at the transcription level at 24 h postprandial (P24 h). However, hyperglycemic was still observed in the HS group with increased enzyme activities of gluconeogenesis (G6P) and glycolytic (PK) at P24 h, which indicated that the spotted seabass could not effectively regulate glycolytic under starvation conditions. Excessive starch intake significantly increased hepatic cAMP content, which enhanced the rate of basal metabolism to relieve hyperglycemia at P24 h. No hepatic glycogen accumulation was observed for both groups, and hepatic glycogen content was significantly decreased with upregulation glycogenolysis (PYGL) in the HS group under starvation conditions. In addition, and lipogenesis and lipolysis/β-oxidation were not affected under satiety conditions (P3 h) in the HS group, while the mRNA levels of lipogenesis genes (FASN, ACC1) and β-oxidation (CPT1α, PPARα) were downregulated under starvation conditions. These results indicated that spotted seabass could preferentially utilize glycogen and then lipids under starvation conditions. In conclusion, the spotted seabass could accelerate basal energy metabolism to relieve hyperglycemia and avoid glycogen accumulation and fatty liver after fed HS diet, and preferentially catabolized hepatic glycogen to provide energy under starvation conditions, which indicated that it could effectively regulate energy metabolism after feeding the HS diet.

Effects of dietary starch levels on growth, feed utilization, glucose and lipid metabolism in non-transgenic and transgenic juvenile common carp (Cyprinus carpio L.)

This experiment investigated the effects of dietary starch on growth performance, feed utilization, glucose and lipid metabolism of non-transgenic and growth hormone (GH) transgenic juvenile common carp (Cyprinus carpio L.). Transgenic common carp (TG fish) and non-transgenic (NT fish) were fed diets with five starch levels (0, 10%, 20%, 30%, 40%). After 41 days, TG fish showed higher growth and feed utilization at low-starch diets, while similar growth, lower feeding rate (FR) and slightly higher feed efficiency (FE) was observed at high-starch diets. Lower plasma glucose level and hepatic glycogen content were observed in TG fish, which could be related to the higher glycolysis (high gene expression of hexokinase (hk), p &lt; 0.01) and gluconeogenesis (high gene expression of fructose-1,6-bisphosphatase (fbpase), p &lt; 0.01; glucose-6-phosphatase (g6pase), p &lt; 0.01) of TG fish. Compared to NT fish, weakened fat synthesis (lower gene expression of fatty-acid synthase (fas), p &lt;0.01; acetyl-CoA carboxylase 1 (acc1), p &lt; 0.01; acyl-CoA desaturase 1 (scd1), p = 0.011) and enhanced fatty acid oxidation (high gene expression of hormone-sensitive lipase (hsl), p =0.01; carnitine palmitoyl transferase 1a (cpt-1a), p &lt; 0.01), led to the decrease of body lipid content in TG fish. On the other hand, with increased dietary starch, increased body lipid and hepatic glycogen contents were observed in both TG and NT fish, suggesting that high dietary starch levels promoted glycolysis, fat synthesis and inhibited gluconeogenesis, fatty acid β-oxidation. Overall, TG fish showed higher growth performance at low starch diets, and higher ability of glycolysis, fatty acid oxidation and lower lipid synthesis than the NT fish.

Effect of dietary energy composition on the energy partitioning between milk production and body fat deposition in late lactating Holstein dairy cows

Whether adjusting the dietary energy composition can prevent the excessive obesity of dairy cows remains elusive. Therefore, this study aimed to investigate the effect of isocaloric diets with different ratios of starch and fat on energy partitioning between milk production and body fat deposition in Holstein dairy cows. Fifty-two cows (days in milk, 210.21 ± 6.95) were divided into 2 groups and fed either a high-starch diet (the ratio of net energy for lactation (NEL) supply by starch: fat was 30%:10%, HS), or a high-fat diet (the ratio of NEL supply by starch: fat was 26.67%:13.33%, HF) for 63 days. The dry matter intake (DMI) and milk yield was recorded daily. Milk samples were collected on day 1, 35 and 63 for composition analysis. The subcutaneous fat thickness was measured by Renco device and the body condition score (BCS) were evaluated on day 1 and 63. The blood biochemical indexes were also measured for the samples collected on day 1 and 63. There was no significant difference in the average DMI between the two dietary treatment groups. However, cows fed with the HS diet had higher (P < 0.05) average milk yield, and the difference enlarged with the duration of the treatments. The cows fed with the HF diet had higher milk fat percentage, serum urea nitrogen concentration, BCS, and backfat thickness (P < 0.05), but lower serum glucose concentrations (P < 0.05). Cows fed the HS diet utilized more energy for lactation (54.22% ME vs. 52.79% ME) but less energy for body fat deposition (0.56% ME vs. 1.94% ME) compared with the animals fed HF diet. Overall, these results indicated that adjusting the dietary energy composition may be an alternative approach to balance the energy partitioning between the lactation and body fat deposition in late lactating Holstein dairy cows.

67 Partial substitution of cereals with sugar beet pulp and hindgut health in horses

In high energy-demanding horses, replacing cereals by sugar beet pulp (SBP) rich in soluble fiber may be of interest to limit hindgut dysbiosis and subsequent mucosal inflammation. This study aimed at evaluating the effect of partial substitution of cereals with SBP on the hindgut microbial ecosystem and the mucosal associated immunity. Six adult exercised Trotteurs Français were enrolled in a 3 × 3 Latin-square design with experimental periods (EP) and wash-out of 21 days each, to test 3 isoenergetic diets distributed in 2 equal meals. On a dry matter (DM) basis, the high-fiber diet (HF) was composed of 100% hay, the high starch diet (HS) of 55% hay and 45% barley, and the high-soluble fiber diet (HSF) of 50% hay, 21% barley and 29% SBP. Horses received hay ad libitum during the wash-out periods. Barley and SBP were introduced gradually during the five first days of each EP. Feces were collected on the last day of each EP to enumerate total anaerobic and cellulolytic bacteria and to measure volatile fatty acids (VFA), lactate, secretory IgA (SIgA) concentrations, DM and pH. Effects of diet, period and their interactionwere tested using MIXED procedure (SAS). Horses fed HS had significantly higher total anaerobes concentration and tended to have lower cellulolytics concentration, confirming hindgut ecosystem alteration with HS (Table 1). No significant diet effect was observed on SIgA concentration. With HSF, cellulolytics counts and total VFA concentrations were higher compared to HS, emphasizing increased fiber hindgut fermentations. In line with the higher amount of highly fermentable fibers in this diet, VFA concentrations were also higher compared to HF. These results suggested that replacing part of cereals by SBP can help limiting hindgut dysbiosis while maintaining a high energy supply through soluble fiber fermentation. Analyses of bacterial diversity and structure, and of blood VFA concentrations would provide further explicative information concerning SBP interest.

41 Macleaya cordata phytotherapic supplementation can modulate immune response in ponies fed a high starch diet

High amounts of grains in equine diet lead to an excessive starch intake modifying microbial populations and fermentative products. These changes could compromise the gastrointestinal barrier which has serious consequences for equine health. Therefore, feed additives are receiving great attention to minimize negative effects related to high starch level inclusion. Macleaya cordata compounds are being used in animal nutrition for their multiple biological effects, including anti-inflammatory and antibiotic properties. However there is no information about effects on horses. The aim of this study was to evaluate effects of increasing levels of a Macleaya cordata commercial phytotherapic on gastrointestinal tract and systemic inflammation of ponies fed a high starch diet. Eight gelding ponies, Mini-Horse breed, healthy, mean age 8.59+0.17 years old and mean body weight (BW) 146.72+16.53 kg were used. Experimental design was contemporary double Latin-square 4 × 4. Experimental unit was the animal inside each experimental period (n = 8 units per treatment). Each experimental period lasted 20 d. Diet attended daily maintenance nutritional requirement of 1.75% BW in dry matter in a concentrate:roughage proportion of 60:40. Daily starch amount was 4.4 g/kg BW, divided in 2 meals. Water and mineral salt were provided ad libitum . Animals were separated in 4 groups: 1) Control: concentrate without food additive, 2) S1: concentrate with 1 mg of phytotherapic/kg BW, 3) S1.5: concentrate with 1.5 mg of phytotherapic/kg BW, 4) S2: concentrate with 2 mg of phytotherapic/kg BW. Right dorsal colon wall thickness was measured by ultrasonography to determine local inflammation at 9:30 a.m. on d 20. Esaote MyLab TM Delta and a micro convex probe were used. Best image was selected using MyLab TM Desk3 software and 3 measures were taken for mean. For systemic inflammation, blood samples were collected at 9 a.m. on d 19. Fibrinogen was dosed by heat precipitation method and interleukins 6 and 10 gene expression in peripheral blood mononuclear cells (PBMC) was obtained using qPCR. Data were analyzed by Statistical Analysis System program with PROC MIXED. Significant level was 5%. Intestinal wall was thinner ( P = 0.0071) in all treated groups (Control: 3.08 mm; S1: 2.59 mm; S1.5: 2.53 mm; S2: 2.44 mm). There were no statistical differences between groups for systemic inflammatory parameters. In conclusion, Macleaya cordata commercial phytotherapic addition in high starch equine diet modulates local immunity, but has no impact on systemic inflammation.

Sequential Modulation of the Equine Fecal Microbiota and Fibrolytic Capacity Following Two Consecutive Abrupt Dietary Changes and Bacterial Supplementation.

Simple SummaryThe equine hindgut is colonized by microorganisms, some of which are involved in fiber digestion and are crucial for the horse’s nutrition and health. These key microorganisms are very sensitive to dietary changes, which have been identified as a risk factor for colics. This study assessed the stressful effect of two consecutive abrupt dietary changes on the diversity, the composition, and the activity of fecal microorganisms focusing on fibrolytic bacteria. Twelve horses were subjected to an abrupt change from forage to a concentrate-rich diet, followed by a second change from a concentrate to forage-rich diet 5 days later. Half of the horses were given a supplement of living bacteria as a probiotic. Two days after the sudden change from forage to concentrate diet, the proportions and types of microorganisms were altered drastically, as was their capacity to degrade fibers. After this dietary stress, it took 3–4 weeks of a high-fiber diet to recover the basal state. Supplementation with probiotics promoted an earlier recovery of fibrolytic bacteria after the dietary stress. Abrupt dietary changes should be limited in horse management to protect the hindgut microorganisms and their capacity to use forage fibers, and consequently to limit the development of colic.In horses, abrupt changes from high-fiber (HF) to high-starch (HS) diets can affect the cecal and colonic microbiota. This study investigated modifications and recovery of fecal microbiota after two consecutive abrupt dietary changes. Twelve horses fed HF for 2 weeks were changed to HS for 5 days then returned to HF for 7 weeks. Six received lactic acid bacteria supplementation. Bacterial population diversity, structure, and activity, especially fibrolysis, were assessed to obtain an overview of alteration in hindgut microbiota. Two days after the abrupt change from HF to HS, the findings in feces were consistent with those previously reported in the cecum and colon, with a decrease in fibrolytic activity and an increase in amylolytic activity. Fecal parameters stabilized at their basal level 3–4 weeks after the return to HF. A bloom of cellulolytic bacteria and lower pH were observed after 1.5 weeks, suggesting a higher level of fiber degradation. In supplemented horses the relative abundance of potentially fibrolytic genera was enhanced 2 days after HS and 2 days to 2–3 weeks after the return to HF. Fecal analysis could be a promising technique for monitoring hindgut microbial variations accompanying dietary changes.

Glucokinase is required for high-starch diet-induced β-cell mass expansion in mice.

Aims/IntroductionWe aimed to determine whether glucokinase is required for β‐cell mass expansion induced by high‐starch diet (HSTD)‐feeding, as has been shown in its high‐fat diet‐induced expansion.Materials and MethodsEight‐week‐old male wild‐type (Gck+/+ ) or glucokinase haploinsufficient (Gck+/− ) mice were fed either a normal chow (NC) or an HSTD for 15 weeks. The bodyweight, glucose tolerance, insulin sensitivity, insulin secretion and β‐cell mass were assessed.ResultsBoth HSTD‐fed Gck+/+ and Gck+/− mice had significantly higher bodyweight than NC‐fed mice. Insulin and oral glucose tolerance tests revealed that HSTD feeding did not affect insulin sensitivity nor glucose tolerance in either the Gck+/+ or Gck+/− mice. However, during the oral glucose tolerance test, the 15‐min plasma insulin concentration after glucose loading was significantly higher in the HSTD group than that in the NC group for Gck+/+ , but not for Gck+/− mice. β‐Cell mass was significantly larger in HSTD‐fed Gck+/+ mice than that in NC‐fed Gck+/+ mice. In contrast, the β‐cell mass of the HSTD‐fed Gck+/− mice was not different from that of the NC‐fed Gck+/− mice.ConclusionsThe results showed that HSTD feeding would increase pancreatic β‐cell mass and insulin secretion in Gck+/+ , but not Gck+/− mice. This observation implies that glucokinase in β‐cells would be required for the increase in β‐cell mass induced by HSTD feeding.

Modulation of ruminal pH, milk fat secretion, and biohydrogenation intermediates by alkalizing agents in dairy cows fed starch-rich diets

We aimed to evaluate the effects of magnesium-based supplements and NaHCO3 on ruminal fermentation parameters, milk fatty acid (FA) profile, and milk fat synthesis in dairy cows fed high-starch diets. Eight second-lactation Holstein dairy cows (4 ruminally-cannulated) averaging 97 ± 12 days in milk and 33 ± 2.5 kg/d of milk were assigned to a replicated 4 × 4 Latin square design with 21-d periods. Cows were fed the following isoenergetic diets (1.64 Mcal/kg DM): (1) the control [342 g/kg starch on dry matter (DM) basis] without any buffering or alkalizing agent, (2) the control plus 8 g/kg DM NaHCO3, (3) the control plus 4 g/kg DM MgO, and (4) the control plus 8 g/kg DM CaMg(CO3)2. Ruminal pH was continuously measured for 72-h in each period using indwelling pH electrodes. Mean ruminal pH was not affected by treatments, but the duration of ruminal pH below 5.8 was shorter (P < 0.01) in cows fed NaHCO3, MgO, or CaMg(CO3)2 diets compared with those fed the control whereas NaHCO3 was more effective than magnesium-based supplements. Similar ability observed for CaMg(CO3)2 and MgO with respect to the duration of ruminal pH below 5.8 responses. The ruminal molar proportion of acetate and acetate-to-propionate ratio was greater (P < 0.05) with magnesium-based supplements and NaHCO3 compared with the control diet. However, the ruminal propionate concentration decreased (P = 0.02) with magnesium-based supplements and NaHCO3 versus the control. The milk proportion and yield of trans-10 C18:1 and total trans-FA dropped and the trans-10/trans-11 C18:1 ratio decreased further, when cows were fed magnesium-based supplements and NaHCO3 compared with the control diet (P < 0.01). Also, adding NaHCO3, MgO, or CaMg(CO3)2 significantly increased yields of trans-11 C18:1 (P < 0.01), de novo (P < 0.01), mixed (P = 0.04), and also preformed FA (P < 0.01) compared with the control diet. The yields of milk, 3.5% fat-corrected, and energy-corrected milk increased (P < 0.01) in cows fed magnesium-based supplements and NaHCO3 due to the improved concentration of milk fat. Overall, supplementing NaHCO3, MgO, and CaMg(CO3)2 in a high-starch diet appears to promote milk fat output by modulating diurnal ruminal pH and ruminal volatile fatty acids profile in dairy cows. Also, it can be concluded that CaMg(CO3)2 has similar ability of MgO in promoting milk fat synthesis and alleviating the time ruminal pH remains below 5.8. Therefore, CaMg (CO3)2 can be used effectively as an alkalizing agent in dairy cow diets containing high-starch and helps to reduce the costs of consumption of the most popular dietary buffers or alkalizers such as NaHCO3 and MgO.

Effects of rosiglitazone on growth and skeletal muscle glucose metabolism of GIFT tilapia based on PI3K/Akt signaling pathway

This study aimed to investigate the effects of rosiglitazone on glucose metabolism of GIFT tilapia based on the PI3K/Akt signalling pathway. The experiment was divided into five groups: normal starch group (32%, LC), high starch group (53%, HC), HC + rosiglitazone group 1 (10 mg/kg, R1), HC + rosiglitazone group 2 (20 mg/kg, R2) and HC + rosiglitazone group 3 (30 mg/kg, R3). The results showed that a high starch diet added with 10–20 mg/kg rosiglitazone had a better specific growth rate and protein efficiency that was beneficial for the growth of the tilapia. With an increase in the rosiglitazone concentration, the contents of serum glucose, insulin and hepatic glycogen in the R1, R2 and R3 groups decreased gradually. Meanwhile, the muscle glycogen content in the R1, R2 and R3 groups increased gradually. The mRNA expression of the IRS-1, PI3K, GLUT-4 and Akt proteins in the R1, R2 and R3 groups was significantly higher than that in the HC group (p < 0.05). Compared with the HC group, the expression of the GSK-3 mRNA in the R1, R2 and R3 groups was significantly reduced (p < 0.05). The protein expression of p-GSK-3β (phosphorylated GSK-3β) in the R1 and R2 groups was significantly higher than that in the HC group (p < 0.05). In conclusion, a high starch diet supplemented with rosiglitazone can improve growth, enhanced the serum biochemical indices and increase the muscle glycogen content in the GIFT tilapia. It benefits in upregulating the IRS-1, PI3K and GLUT-4 mRNA in the skeletal muscle and promotes glucose uptake. Meanwhile, the phosphorylation of Akt and GSK-3β increased significantly and resulted in the inactivation of GSK-3β and alleviation of insulin resistance. Under these experimental conditions, the optimal dosage of rosiglitazone on tilapia was 10–20 mg/kg diet.

Starch–protein interaction in the rumen of weaned dairy calves

The objectives of this study were to investigate the effect of starch and protein interaction on rumen environment, in situ digestion, and total-tract digestibility of nutrients in weaned dairy calves between 8 and 16 wk of age. Sixteen rumen-cannulated calves were randomly divided into 4 dietary treatment groups with 4 calves fed in each treatment. The treatment diets had 2 levels of starch [18%, low starch (LS), or 38%, high starch (HS)] and 2 levels of protein [16%, low protein (LP), or 22%, high protein (HP)] on a dry matter (DM) basis in calf grower: (1) LPLS, (2) LPHS, (3) HPLS, and (4) HPHS. Calves were fed for ad libitum intake (95% assigned grower and 5% grass hay), and refusals were collected weekly. Total-tract digestibility collection and in situ digestibility procedures were performed for each calf at 11 and 15 wk. Samples for in situ digestibility, grass hay (GH), soybean hulls (SBH), wheat middlings (WM), ground corn (GrC), and soybean meal (SBM) were incubated for 9 and 24 h. There was no starch and protein interaction on total-tract digestibility of calves. Total-tract DM, neutral detergent fiber (NDF) and acid detergent fiber (ADF) digestibility, and feed efficiency were affected by both protein and starch inclusion level in calf diet. Total-tract starch digestibility was lower for LS diets. Dry matter digestibility and feed efficiency were greater in calves fed HP and HS diets compared with calves fed LP and LS diets, respectively. Fiber digestibility (NDF and ADF) was less in calves fed HS diets compared with calves fed LS diets but was greater in calves fed HP diets compared with calves fed LP diets. Level of protein did not affect in situ DM and NDF disappearance of GH, but HP increased in situ DM and NDF disappearance of SBH. High-starch diets decreased DM and NDF disappearance of both GH and SBH. At 20 h after feeding, ruminal pH was 0.51 unit higher in calves fed HPHS compared with calves fed LPHS. Total ruminal VFA and proportion of propionate was greater with HS versus LS, whereas proportion of acetate was greater with LS versus HS. The DM disappearance of SBM and WM and NDF disappearance of WM was greater for calves fed HPHS compared with calves fed LPHS at 11 wk of age. In our study, when HP was fed with HS, rumen pH, in situ digestion of WM and SBM, and total-tract digestion of DM, NDF, and ADF increased. This provides evidence for starch-protein interaction in the rumen of recently weaned dairy calves. Improvements in total-tract and in situ digestibility suggest that both protein and starch levels are important for 8- to 16-wk-old calves.

Rosiglitazone promotes glucose metabolism of GIFT tilapia based on the PI3K/Akt signaling pathway.

The study aimed to explore the effects of rosiglitazone on glucose metabolism of GIFT tilapia based on the PI3K/Akt signaling pathway. The experiment was divided into five groups: normal starch group (32%, LC), high starch group (53%, HC), high starch +rosiglitazone group 1 (10 mg/kg, R1), high starch + rosiglitazone group 2 (20 mg/kg, R2), and high starch + rosiglitazone group 3 (30 mg/kg, R3). The results showed that a high starch diet supplemented with 10–20 mg/kg rosiglitazone had a better specific growth rate and protein efficiency that was beneficial for the growth of the tilapia. Rosiglitazone had no significant effect on the contents of crude lipid, crude protein, crude ash, and moisture of the whole fish body (p > 0.05). The contents of triglycerides and total cholesterol in the R1, R2, and R3 groups were lower than those in the HC group. The levels of glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) in R1 and R2 groups were significantly lower than those in the HC groups (p < 0.05). However, the GOT and GPT levels in the R3 groups were significantly higher than those in the R1 and R2 groups (p < 0.05). With an increase in the rosiglitazone concentration, the contents of serum glucose, insulin, and hepatic glycogen in the R1, R2, and R3 groups decreased gradually. Meanwhile, the muscle glycogen content in the R1, R2, and R3 groups increased gradually. The mRNA expression of the IRS‐1, PI3K, GLUT‐4, and Akt proteins in the R1, R2, and R3 groups was significantly higher than that in the HC group (p < 0.05). Compared with the HC group, the expression of the GSK‐3 mRNA in the R1, R2, and R3 groups was significantly reduced (p < 0.05). The protein expression of p‐Akt in the R1 and R2 groups was higher than that in the HC group (p > 0.05). The protein expression of p‐GSK‐3β in the R1 and R2 groups was significantly higher than that in the HC group (p < 0.05). In conclusion, a high starch diet supplemented with rosiglitazone can improve growth, enhance the serum biochemical indices, and increase the muscle glycogen content in the GIFT tilapia. It benefits in upregulating the IRS‐1, PI3K, and GLUT‐4 mRNA levels in the skeletal muscle and promotes glucose uptake. Meanwhile, the phosphorylation of Akt and GSK‐3β increased significantly and resulted in the inactivation of GSK‐3β and alleviation of insulin resistance.

Evaluating the effects of Lactobacillus animalis and Propionibacterium freudenreichii on performance and rumen and fecal measures in lactating dairy cows

Two experiments evaluated the effect of supplementation with a bacterial direct-fed microbial on performance and apparent total-tract nutrient digestion of dairy cows. In experiment 1, 30 multiparous cows (75 ± 32 d in milk) were randomly assigned to 1 of 2 treatments fed for 10 wk. All cows were fed a diet containing 23.8% starch. Treatments were top dressed to rations twice daily and consisted of a combination of Lactobacillus animalis (1 × 109 cfu/d) and Propionibacterium freudenreichii (2 × 109 cfu/d; LAPF) or carrier alone (CON). In experiment 2, 6 ruminally cannulated cows (123 ± 129 d in milk) were randomly assigned to a crossover design with two 6-wk periods. Cows received the same CON or LAPF treatment as in experiment 1. Cows were fed the same 23.8% starch diet as experiment 1 during wk 1 through 5 of each period, and then cows were abruptly switched to a 31.1% starch diet for wk 6. For both experiments, intake and milk yield were measured daily, and milk samples were collected weekly. In experiment 1, fecal grab samples were collected every 6 h on d 7 of experimental wk 1, 2, 4, 6, 8, and 10. Fecal consistency was scored, and fecal starch was measured in daily composite samples. Fecal composites from a subset of 7 cows per treatment were used to measure apparent total-tract nutrient digestion. In experiment 2, rumen pH was continuously recorded during wk 5 and 6. On d 7 of wk 5 (the final day of feeding the 23.8% starch ration), d 1 of wk 6 (the day of diet transition), and d 7 of wk 6 (the final day of feeding the 31.1% starch ration), rumen in situ digestion was determined. Samples of rumen fluid and feces were collected every 6 h on those days for measurement of fecal starch (composited by cow within day), rumen volatile fatty acids, and fecal pH. Rumen and fecal samples were collected at one time point on those days for microbiota assessment. In experiment 1, treatment did not affect intake, milk yield, milk composition, or fecal score. The LAPF treatment decreased fecal starch percentage and tended to increase starch digestion compared with CON, but the differences were very small (0.59 vs. 0.78% and 98.74 vs. 98.46%, respectively). Digestion of other nutrients was unaffected. In experiment 2, LAPF increased rumen pH following the abrupt switch to the high-starch diet, but milk yield was lower for LAPF compared with CON (35.7 vs. 33.2 kg/d). Contrary to the decrease in fecal starch with LAPF observed in experiment 1, fecal starch tended to be increased by LAPF following the abrupt ration change in experiment 2 (2.97 vs. 2.15%). Few effects of treatment on rumen and fecal microbial populations were detectable. Under the conditions used in our experiments, addition of the bacterial direct-fed microbials did not have a marked effect on animal performance, ruminal measures, or total-tract nutrient digestion.

Polymorphisms of AMY1A gene and their association with growth, carcass traits and feed intake efficiency in chickens

Investigations on the association between chicken traits and genetic variations can provide basic information to improve production performance in chickens. In our previous work, we genotyped 450 male chickens with a 600 K SNP array [1] and found that several SNPs in the genomic regions of the amylase alpha 1A (AMY1A) gene were significantly associated with feed intake efficiency and carcass traits. Given the lower accuracy of the SNP array, we performed direct sequencing with male and female chickens to further test chicken AMY1A polymorphisms and investigate their association with 17 traits in chickens. The results showed that 7 SNPs in the 5′ flanking region, exon, intron and 3’ UTR (3′ untranslated region) of AMY1A, were significantly associated with daily gain (DG), average daily feed intake (ADFI), leg muscle weight (LMW) and abdominal fat (AF) (p < 0.05). Additionally, the haplotypes based on three SNPs, rs15910189, rs314354067 and rs316026696, showed significant associations with DG (p < 0.01), ADFI and AF (p < 0.05). To better understand the transcriptional regulation of AMY1A, we cloned its 5′ flanking region and found that the SNPs rs316436216 and rs314213090 which might change the transcriptional regulator binding sites, were in the suppressor and enhancer regions, respectively. In addition, luciferase assays revealed that the SNP rs314613110 in the 3’ UTR influenced the binding of the miRNA gga-miR-1764-3p. To validate whether there is any copy number variation in AMY1A in our population, we performed a genome-wide assessment of CNVs through whole-genome resequencing data. However, no CNV was found in AMY1A in our population, which is different from the increased copy number of AMY1A found in humans who consume a high-starch diet. Therefore, the present study provides substantial evidence for the association of AMY1A polymorphisms with growth traits and feed intake efficiency, which might contribute to chicken breeding programs.