Efficacy of maize differing in particle size in low-density protein diets fed to broilers from day 1 to 21 of age.

1. This study evaluated the efficacy of maize differing in particle size in low-density protein diets on performance, the digestive tract and litter characteristics in broilers. Four dietary treatments; control commercial diet with a typical crude protein content 22.50% (CON); CON + 20% maize with particle size 350 µm (M350), crude protein 19.90%; CON + 20% maize with particle size 2600 µm (M2600), crude protein 19.90%); CON + 20% whole maize (WM), crude protein 19.90%, were fed ad libitum to broiler chicks up to 21 d of age.2. No differences in body weight gain, feed intake and FCR were found between the WM and CON. WM increased body weight gain compared to M350 and M2600. M350, M2600 and WM increased (p = 0.004) gizzard relative weight compared with CON on day 14. Both WM and M2600 reduced (p = 0.001) gastric isthmus diameter on d 14 and 21 compared with CON and M350.3. No differences were seen in mucosa for the Lamina propria and the extent of Tunica muscularis of gizzard on d 21 and ileum mucosal depth on d 14 between WM and CON diets. However, WM reduced villus-to-crypt ratio compared with CON on d 21. The M350 reduced (p < 0.05) gizzard digesta particle size compared with CON, M2600 and WM on d 14.4. Both WM and M350 decreased (p < 0.05) nitrogen excretion compared to birds fed CON. Feeding WM increased nitrogen efficiency compared with M350 and M2600 diets, but was similar to birds fed CON. Feeding M350, M2600 or WM decreased (p < 0.05) litter moisture and footpad dermatitis (FPD) scores compared with results from birds fed CON.5. Overall, diluting the protein level in broiler diets with whole maize appeared better than fine or coarse maize in terms of growth performance, digestive tract development, nitrogen excretion and litter parameters. This may lead to economic benefits by reducing grinding costs and dependence on rich protein resources contributing to sustainable meat production and food security.

Use of wheat dilution to improve digestive function in broilers: application in low protein diets.

1. This study evaluated the effect of wheat dilution increasing in particle size in low crude protein diets on growth performance, digestive tract, nitrogen efficiency and litter quality in broiler chickens.2. Ross 308 male broiler chicks (n = 336) were allocated to one of four dietary treatments (each with 7 pens, 12 chicks per pen); Control (CON; commercial pellet diet with standard crude protein, CP: 22.50%), W578 (CON +20% wheat of geometric mean diameter (GMD) of 578 µm; CP: 20.25%), W1326 (CON +20% wheat of GMD 1326 µm; CP: 20.25%) and WW (CON +20% whole wheat, CP: 20.25%), from d 0 to 21 of age.3. Body weight gain was increased (P < 0.05) for birds fed CON compared to the low crude protein diets. However, WW increased (P < 0.05) body weight gain compared to W578 and W1326, while feed intake and feed conversion ratio on CON and WW were similar (P > 0.05). Birds fed W1326 showed the poorest (P < 0.05) FCR compared to CON, W578 and WW.4. Gizzard relative weight (g/kg body weight) was increased (P < 0.05) on WW compared to CON on d 14 and 21, whereas gastric isthmus diameter was significantly reduced on W1326 and WW compared with CON and W578.5. There were no differences (P > 0.05) in the depth of gizzard mucosa of lamina propria between CON and WW at d 14 and 21. Birds fed WW increased (P < 0.05) gizzard tensile strength compared to W578 and W1326, whereas no difference was observed between WW and CON on d 14.6. No significant differences were seen for ileum villus height and mucosal layer between CON and WW on d 21, however, feeding CON increased the extent of the mucosal layer compared to W578 and W1326.7. Nitrogen excretion (g/kg BWG) was significantly lower (P > 0.05) on W1326 and WW compared with CON and W578. Litter nitrogen, moisture, and footpad scores significantly decreased (P < 0.05) for birds fed WW compared with CON.8. Diluting dietary protein content from 22.50 to 20.25% resulted in lower body weight gain in broilers. However, dilution with whole wheat resulted in comparable FCR, reduced nitrogen excretion, litter moisture and footpad dermatitis compared with a standard protein diet.

Xylo-oligosaccharide-based prebiotics upregulate the proteins of the Sus-like system in caecal Bacteroidetes of the chicken: evidence of stimbiotic mechanism.

The present study was conducted to investigate the stimbiotic mechanism of xylo-oligosaccharide (XOS) in degrading the complex polysaccharides by the caecal bacteria of the chicken, by applying a proteomic approach. A total of 800 as-hatched Ross 308 broiler chicks were equally divided into 4 experimental pens (200 chicks per pen) at a commercial poultry barn, allocating 2 pens per treatment. Birds were fed ad libitum with 2 dietary treatments; CON (without XOS) and XOS (with 0.1g XOS/kg diet) from d 0 to 35. From each pen, 60 Individual birds were weighed weekly whereas caecal content was obtained from 5 birds cervically dislocated on d 35. The caecal bacteria were lysed and their proteins were quantified using label-free quantitative proteomic mass spectrometry. The results showed that XOS significantly increased (P < 0.05) bird weight on d 7, 14, 21, and 28, and body weight gain on d 7, 14, 21, and 35 compared to CON. However, no difference (P > 0.05) in body weight gain was observed from d 0 to 35 between CON and XOS. The proteomic analysis of caecal bacteria revealed that 29 proteins were expressed differently between the CON and the XOS group. Out of 29, 20 proteins were significantly increased in the XOS group compared to CON and 9 of those proteins belonged to the starch-utilizing system (Sus)-like system of the gram-negative Bacteroidetes. Bacteroides thetaiotaomicron (Bt) is a significant constituent of the human gut microbiota, known for its remarkable ability to hydrolyze most glycosidic bonds of polysaccharides. This microorganism possesses a 5-protein complex in its outer membrane, named the starch utilization system (Sus), responsible for adhering to, breaking down, and transporting starch into the cell. Sus serves as an exemplar system for numerous polysaccharide utilization loci that target glycans found in Bt and other members of the Bacteroidetes phylum. The proteins of the Sus-like system are involved in the degradation of complex polysaccharides and transportation of the oligosaccharides into the periplasm of the caecal bacteria where they are further broken down into smaller units. These smaller units are then transported into the cytoplasm of the cell where they are utilized in metabolic pathways leading to potential generation of short-chain fatty acids, thus improving the nutritive value of residual feed. In conclusion, XOS supplementation upregulates the expression of the proteins of the Sus-like system indicating its role as a stimbiotic.

Effects of dietary supplementation with a laminarin-rich extract on the growth performance and gastrointestinal health in broilers.

Restriction in antimicrobial use in broiler chicken production is driving the exploration of alternative feed additives that will support growth through the promotion of gastrointestinal health and development. The objective of this study was to determine the effects of dietary inclusion of laminarin on growth performance, the expression of nutrient transporters, markers of inflammation and intestinal integrity in the small intestine and composition of the caecal microbiota in broiler chickens. Two-hundred-and-forty day-old male Ross 308 broiler chicks (40.64 (3.43 SD) g) were randomly assigned to: (T1) basal diet (control); (T2) basal diet + 150 ppm laminarin; (T3) basal diet + 300 ppm laminarin (5 bird/pen; 16 pens/treatment). The basal diet was supplemented with a laminarin-rich Laminaria spp. extract (65% laminarin) to achieve the two laminarin inclusion levels (150 and 300 ppm). Chick weights and feed intake was recorded weekly. After 35 days of supplementation, one bird per pen from the control and best performing (300 ppm) laminarin groups were euthanized. Duodenal, jejunal and ileal tissues were collected for gene expression analysis. Caecal digesta was collected for microbiota analysis (high-throughput sequencing and QPCR). Dietary supplementation with 300 ppm laminarin increased both final body weight (2033 vs. 1906 ± 30.4, P < 0.05) and average daily gain (62.3 vs. 58.2 ± 0.95, P < 0.05) compared to the control group and average daily feed intake (114.1 vs. 106.0 and 104.5 ± 1.77, P < 0.05) compared to all other groups. Laminarin supplementation at 300 ppm increased the relative and absolute abundance of Bifidobacterium (P < 0.05) in the caecum. Laminarin supplementation increased the expression of interleukin 17A (IL17A) in the duodenum, claudin 1 (CLDN1) and toll-like receptor 2 (TLR2) in the jejunum and IL17A, CLDN1 and SLC15A1/peptide transporter 1 (SLC15A1/PepT1) in the ileum (P < 0.05). In conclusion, supplementation with laminarin is a promising dietary strategy to enhance growth performance and 300 ppm was the optimal inclusion level with which to promote a beneficial profile of the gastrointestinal microbiota in broiler chickens.

Efficacy and stability of a novel silica supplement for improving bone development in broilers.

1. The essentiality of silicon for skeletal development has been established, but the adequacy of bioavailable silicon supply in broiler diets has not been considered for 30 years, despite average daily weight gain of birds increasing by almost a third over that time. Therefore, two studies were undertaken to investigate whether modern strains of broiler chicken benefit from diet supplementation with bioavailable silica. 2. Trial 1 was a 2x2x2 factorial study where six replicate pens of seven chicks were fed one of the eight freshly prepared diets from hatch to 21 days of age, with bodyweight gain and feed intake recorded weekly. Diets combined the following factors: silicon supplement fed at 0 ppm or 1000 ppm, phytase levels of either 0 FTU/kg or 1500 FTU/kg and either 0.6% or 0.7% Ca. Tibia were analysed for bone breaking strength, extent of tibial dyschondroplasia and feet measured for bone ash and pododermatitis score. 3. Trial 2 used a 0.7% Ca with 1500 FTU phytase diet as the control and compared this with the same diet containing either 1000 ppm silicon (MONO-Si) freshly added each week or 1000 ppm silicon added in a single, advance-prepared batch per feeding phase. Each diet was fed to nine pens of seven birds from 0 to 35 d with feed consumption and weight recorded weekly. Two birds per pen were euthanised on d 14, 21 and 35 and tibias collected for measurement of bone breaking strength, ash and mineral content. Serum was collected for Si content. 4. Univariate analysis of means from each trial showed that silica supplementation improved bird weight gain over the starter phase, though there was no effect on feed conversion. 5. Bone strength improved with added silica in both studies, without affecting bone mineral content; indicating that modern strains of broiler may require dietary supplementation with bioavailable silicon.

Bioavailability of a novel form of silicon supplement.

In this study, we assessed uptake and potential efficacy of a novel, pH neutral form of silicon supplement in vitro and using broiler chickens as a model species. In vitro bioavailability of this supplement was significantly higher than other commercial supplements tested, all of which claim available silica content. To confirm bioavailability of the new supplement in vivo, a broiler chick feeding trial reported blood uptake that was significantly higher than a Bamboo-derived silicon supplement. We assessed dose response of the novel supplement in a further study with increased dose related levels of silicon being detected in the blood and tibia. We found tibia and foot ash residue as a percentage of dry mass was higher with inclusion of the novel supplement in the diet, particularly in young birds and that this was followed by significant increase in tibia breaking strength. This novel supplement may therefore have applications in the improvement of bone integrity, with implications for the reduction of lameness in broilers. These results indicate the novel silica supplement is readily absorbed in chicks, and transported in the blood supply to sites such as the skeleton due to it being present in a non-condensed, monomeric form. There is potential for wider application of this silica supplement in other species where bone breakages are a problem, including high performance sport.

Effect of supplementation of phytase to diets low in inorganic phosphorus on growth performance and mineralization of broilers.

There has been discussion regarding microbial phytase replacing inorganic phosphorus (P) supplementation in broiler diets. Therefore, an experiment was conducted to examine the effect of phytase supplementation on diets low in inorganic P. Ross 308 broilers (n = 288) were fed one of 6 experimental diets in 4 phases. The control diet had 16.20, 10.90, 9.40, and 6.10 g/kg inorganic P in the Starter, Grower 1, Grower 2 and Finisher phase respectively. The remaining diets had 10.50 g/kg inorganic P in the Starter phase. Two of the diets had graded reductions in inorganic P of 5.10, 3.60, and 0.60 g/kg or 2.00, 0.50, and 0.60 g/kg for the Grower 1, Grower 2 and Finisher phase respectively, plus 500 FTU phytase. Three of the diets had inorganic P levels of 0.40, 0.50, and 0.60 g/kg for the Grower 1, Grower 2 and Finisher diets respectively and either 500, 750, or 1,000 FTU phytase. Broiler performance was analyzed at d 10, 20, 26, and 35. On d 35, ileal calcium (Ca) and P digestibility and tibia bone strength, mineralization, and mineral content were analyzed. There were no significant differences between the control diet and diet containing 1,000 FTU phytase and low inorganic P in the grower or finisher diets based on bird performance, tibia strength, and Ca and P digestibility. Birds fed the control diet had significantly higher BWG (P = 0.001), bone strength (P < 0.001) and ash content (P < 0.001) compared to birds fed the diets with 500 FTU or 750 FTU phytase and low inorganic P in the grower and finisher stages. This may be due to incomplete dephosphorylation of the inositol ring of phytate with these doses of phytase, but with 1,000 FTU phytase there was almost complete phosphate hydrolysis of each phytate. This study showed that relying on phytase alone to ensure full supply of P in broiler diets is viable in finisher diets but is not recommended in grower diets unless phytase is supplied at doses of 1,000 FTU or greater.

Use of Zn concentration in the gastrointestinal tract as a measure of phytate susceptibility to the effect of phytase supplementation in broilers.

Zinc (Zn) is the most vulnerable cation to complexation with phytate. An experiment was conducted to evaluate the potential of measurements of Zn concentration in the gastrointestinal tract as a marker to assess the anti-nutritional impact of phytate and susceptibility of phytate to phytase in broilers. Ross 308 broilers (n = 180) were fed one of 5 experimental diets with differing phytase activity levels, analyzed at 605, 1150, 1804, 3954, and 5925 U/kg. Broiler performance and Zn concentration, pH, and amount of phytate hydrolyzed in the gizzard, duodenum, and ileum were analyzed at d 21 post hatch. Phytate susceptibility to phytase degradation was determined in vivo and in vitro by measuring total phytate-P hydrolyzed in the tract or in conditions that mimicked the tract, respectively. Phytase activity level had a significant (P < 0.05) impact on Zn concentration and phytate hydrolyzed in the gizzard and ileum, but not in the duodenum. Strong relationships were observed between the amount of phytate hydrolyzed and Zn concentration in the gizzard in birds fed the diets with 1804 U/kg or higher levels of phytase. Phytate and phytase effects could therefore potentially be evaluated by measuring Zn concentration in the gizzard. Susceptible phytate levels measured in vivo and in vitro were almost identical in the diet with phytase activity of 5925 U/kg, but in the diets with lower phytase activity levels the in vitro assay overestimated the amount of P released. There were strong relationships between in vivo susceptible phytate level and pH and amount of phytate hydrolyzed in the gizzard, duodenum, and ileum and Zn concentration in the gizzard and ileum. This illustrates that phytate susceptibility directly effects mineral availability in the gastrointestinal tract. Measurements of Zn concentration in the gastrointestinal tract, particularly in the gizzard, can potentially be used as a marker to assess the anti-nutritional impact of phytate and susceptibility of phytate to phytase in broilers.

The bio refinery; producing feed and fuel from grain.

It is both possible and practicable to produce feed and fuel from grain. Using the value of grain to produce renewable energy for transport, while using the remaining protein content of the grain as a valuable protein source for livestock and for fish, can be seen as a complimentary and optimal use of all the grain constituents. Consideration must be given to maximise the value of the yeast components, as substantial yeast is generated during the fermentation of the grain starch to produce ethanol. Yeast is a nutritionally rich feed ingredient, with potential for use both as feed protein and as a feed supplement with possible immunity and gut health enhancing properties. Bioprocessing, with the consequent economies of scale, is a process whereby the value of grain can be optimised in a way that is traditional, natural and sustainable for primarily producing protein and oil for feed with a co-product ethanol as a renewable fuel.

Contribution of intestinal- and cereal-derived phytase activity on phytate degradation in young broilers.

There is little consensus as to the capability of poultry to utilize dietary phytate without supplemental phytase. Therefore, an experiment was conducted to examine the extent to which endogenous phytase of intestinal and cereal origin contributes to phytate degradation in birds aged 0 to 14 d posthatch. Ross 308 broilers (n = 720) were fed one of 4 experimental diets with differing dietary ingredient combinations and approximate total phytate levels of 10 g/kg, dietary phytase activity analyzed at 460 U/kg, dietary calcium (Ca) levels of 11 g/kg, and nonphytate-phosphorus (P) levels of 4 g/kg. Broiler performance, gizzard, duodenum, jejunum and ileum pH, Ca and P digestibility and solubility, amount of dietary phytate hydrolyzed in the gizzard, jejunum, and ileal digesta phytase activity were analyzed at d 4, 6, 8, 10, 12, and 14 posthatch. Intestinal endogenous phytase activity increased significantly (P < 0.001) between d 4 and 6, resulting in increased phytate hydrolysis in the gizzard (P = 0.003), jejunum (P < 0.001), and ileum (P < 0.001). Phytase activity and phytate hydrolysis continued to increase with age, with a greater phytase activity and associated increase in phytate hydrolysis and mineral utilization between d 10 and 12. Gizzard and jejunum Ca and P solubility and ileal Ca and P digestibility increased significantly (P < 0.001), and gastrointestinal pH decreased significantly (P < 0.001) between d 4 and 6. By d 14, phytase activity recovered in the ileum was approximately 45 U/kg. There were strong correlations between phytase activity measured in the ileum and phytate hydrolyzed in the gizzard (r = 0.905, P < 0.001), jejunum (r = 0.901, P = 0.023), and ileum (r = 0.938, P = 0.042). This study shows intestinal- and dietary-derived endogenous phytase activity is responsible for phytate-P hydrolysis in broilers.

In vitro versus in situ evaluation of the effect of phytase supplementation on calcium and phosphorus solubility in soya bean and rapeseed meal broiler diets.

1. In vitro assays provide a rapid and economical tool to evaluate dietary effects, but have limitations. In this study, the effect of phytase supplementation on solubility, and presumed availability, of calcium (Ca) and phosphorus (P) in soya bean meal (SBM) and rapeseed meal (RSM) based diets were evaluated both in situ and by a two-step in vitro digestion assay that simulated the gastric and small intestine (SI) phases of digestion. 2. Comparison of the in vitro findings to in situ findings was used to evaluate the in vitro assay. Ross 308 broilers (n = 192) were fed on one of 6 SBM or RSM diets supplemented with 0, 500 or 5000 FTU/kg phytase from 0 to 28 d post hatch. The 6 diets and raw SBM and RSM were exposed to a two-step in vitro assay. Ca and P solubility and pH in the gizzard and jejunal digesta and in the gastric and SI phase of in vitro digestion were measured. 3. Both in vitro and in situ analyses detected that Ca solubility was lowest when diets were supplemented with 500 FTU/kg phytase, compared to the control diets and diets supplemented with 5000 FTU/kg phytase. Phosphorus solubility increased with increasing phytase level. Both methods also identified that mineral solubility plateaus in the gastric phase. 4. Overall relationship of the two methods was strong for both determination of gastric phase Ca and P solubility (r = 0.96 and 0.92, respectively) and also SI phase Ca and P solubility (r = 0.71 and 0.82, respectively). However, mineral solubility and pH were higher when measured in vitro than in situ, and the in situ assay identified an interaction among the effects of phase, protein source and phytase inclusion level on Ca solubility that the in vitro assay did not detect. 5. This two-step in vitro assay successfully predicted phytase efficacy, but to determine detailed response effects in the animal, in situ data is still required.

The effect of dietary calcium inclusion on broiler gastrointestinal pH: quantification and method optimization.

There is little consensus as to the most appropriate methodology for the measurement of gastrointestinal pH in chickens. An experiment was conducted to establish the optimum sampling method for the determination of broiler digesta pH in birds fed differing levels of dietary calcium. Ross 308 broilers (n = 60) were fed 1 of 2 experimental diets, one containing 0.8% monocalcium phosphate and 2% limestone and one containing 0.4% monocalcium phosphate and 1% limestone. Four factors were investigated to determine the most appropriate method of measuring broiler gastrointestinal digesta pH: removal from the tract, prolonged air exposure, altering the temperature of the assay, and controlling the water content of the digesta. The conditions were assessed at bird ages from 7 to 42 d posthatch. Dietary Ca content had no significant effect on in situ pH, but it contributed toward variance in ex situ pH of both gizzard and duodenum digesta. Digesta pH read higher when the digesta was removed from the tract, but the amount of time the digesta was exposed to air did not affect the reading. Digesta pH read higher when measured at room temperature than when measured at 41°C; temperature made the strongest unique contribution to explaining variance in duodenum pH, and the second strongest contribution to explaining variance in gizzard pH, after diet. When water was added to the digesta, before pH determination, the pH of the digesta read higher (P < 0.001) than when measured in situ. The method that resulted in pH readings that were most representative of bird gastrointestinal environment was insertion of a pH probe directly into the gut lumen posteuthanasia, because measurement ex situ likely encourages dissociation of carbonic acid, the major buffer in the gastrointestinal tract, which causes pH to read to be higher than when measured in situ. This study shows that the method of pH measurement needs careful consideration to ensure the validity of the result.

A comparison of two methods for determining titanium dioxide marker content in broiler digestibility studies.

The use of inert markers in broiler diets eliminates the need to quantitatively evaluate feed intake and excreta output to determine diet digestibility, and enables nutrient uptake at specific points along the gastrointestinal tract to be examined. Titanium dioxide (TiO2) is commonly used for this purpose and measured using a UV-spectrophotometric assay. Two experiments were conducted to observe whether an inductively coupled plasma optical emission spectrophotometer (ICP-OES) assay is able to replace the UV-spectroscopy assay for rapid analysis of TiO2 in broiler feed and ileal digesta samples. In the first experiment, TiO2 was added at 5 g/kg to 19 broiler diets. Ross 308 male broilers (n=452) fed these diets were involved in a series of digestion studies to determine ileal digesta recovery of TiO2. In the second experiment, defined amounts of TiO2 were added to ileal digesta samples from Ross 308 male broilers (n=176) and TiO2 recoveries were determined. The feed and ileal samples from both experiments were analysed by both UV-spectroscopy and ICP-OES, and relatedness of the findings from the two assays was determined. Overall relatedness of the two assays was strong for determination of TiO2 concentration in both the broiler diets and ileal digesta samples (r=0.908 and r=0.884, respectively). Overall recovery of supplemented TiO2 was 97.62% by the UV-spectroscopy assay and 98.77% by the ICP-OES assay. The ICP-OES assay in this study was as accurate as spectrophotometric determination for the quantification of TiO2 content. The ICP-OES method can also be used to analyse several elements within one assay, with a single preparation step, and thus the measurement of TiO2 may be incorporated into the analysis of other minerals. Time and resources dedicated to determining diet digestibility in broilers could be minimised by using the ICP-OES assay to replace the UV-spectroscopy assay when measuring TiO2 concentration.

Evaluation of a fast, objective tool for assessing body condition of budgerigars (Melopsittacus undulatus).

There is currently no suitable system available for the assessment of budgerigar body condition. A tool has been developed that uses an algorithmic decision tree of yes-no answers based on physical examination to objectively guide the assessor to a body condition score. The aim of this work was to evaluate the guide. Repeatability and reproducibility were measured by four assessors on three sequential days, using 38 budgerigars of mixed sex, age and weight. Data were analysed using a 3-factor anova, with Person and Bird as variable factors and occasion as a fixed factor. The association between body condition score and body fat was measured using three assessors and 63 dead budgerigars, which were chemically analysed for fat content after assessment. Data were statistically analysed to determine correlation using Spearman's Rank Coefficient. Occasion and person had no significant effect on body condition score (p = 0.988 and 0.347 respectively). Body condition score and percentage body fat were highly significantly correlated (R(2) = 0.768): percentage fat increased with increasing body condition score. The guide would appear to be a repeatable measure of body condition in budgerigars, suitable for use during physical examinations.

Quantitative neurodegenerative pathology does not explain the degree of hippocampal atrophy on MRI in degenerative dementia.

OBJECTIVE: The purpose of this study was to investigate the neuropathological substrates underlying in vivo hippocampal atrophy on magnetic resonance imaging (MRI) in autopsy confirmed neurodegenerative dementia cases. METHODS: Thirty-one neuropathologically verified cases (23 with Lewy body dementia (LBD) and eight with Alzheimer's disease (AD)) were included who had undergone an MRI scan close to death (mean 1.5 years). Manual volumetric measurements were undertaken for the hippocampus, entorhinal cortex and amygdala on MRI, along with quantitative neuropathological analysis of plaque, tangle and Lewy body pathology in the same regions. The relationship between neuropathology and MRI volumes was assessed using correlations and linear regression. RESULTS: Hippocampal and amygdala volumes were significantly smaller in cases with AD than with LBD, but there was no difference in entorhinal cortex volume. Analysing all cases together, a significant positive correlation was observed between normalised hippocampal volume and percent area of Lewy bodies in the hippocampus (r=0.449, p=0.017) but not with tangles (r=0.059, p=0.766) or plaques (r=-0.361, p=0.119). There were no other significant correlations between regional MRI volume and measures of neuropathology. Regression analysis showed that overall diagnosis of AD rather than burden of individual pathological changes was the most significant predictor of hippocampal volume loss in autopsy confirmed cases. CONCLUSION: Our results suggest that (i) hippocampal and amygdala but not entorhinal cortex, volumes differ between AD and LBD and (ii) factors other than current markers of neurodegenerative pathological change are responsible for atrophy of medial temporal lobe structures in AD and LBD.

Medial temporal lobe atrophy on MRI differentiates Alzheimer's disease from dementia with Lewy bodies and vascular cognitive impairment: a prospective study with pathological verification of diagnosis.

The purpose of this study was to determine the diagnostic accuracy of medial temporal lobe atrophy (MTA) on MRI for distinguishing Alzheimer's disease from other dementias in autopsy confirmed cases, and to determine pathological correlates of MTA in Alzheimer's disease, dementia with Lewy bodies (DLB) and vascular cognitive impairment (VCI). We studied 46 individuals who had both antemortem MRI and an autopsy. Subjects were clinicopathologically classified as having Alzheimer's disease (n = 11), DLB (n = 23) or VCI (n = 12). MTA was rated visually using a standardized (Scheltens) scale blind to clinical or autopsy diagnosis. Neuropathological analysis included Braak staging as well as quantitative analysis of plaques, tangles and alpha-synuclein Lewy body-associated pathology in the hippocampus. Correlations between MTA and pathological measures were carried out using Spearman's rho, linear regression to assess the contributions of local pathologic changes to MTA. Receiver operator curve analysis was used to assess the diagnostic specificity of MTA for Alzheimer's disease among individuals with Alzheimer's disease, DLB and VCI. MTA was a highly accurate diagnostic marker for autopsy confirmed Alzheimer's disease (sensitivity of 91% and specificity of 94%) compared with DLB and VCI. Across the entire sample, correlations were observed between MTA and Braak stage (rho = 0.50, P < 0.001), per cent area of plaques in the hippocampus (rho = 0.37, P = 0.014) and per cent area of tangles in the hippocampus (rho = 0.49, P = 0.001). Linear regression showed Braak stage (P = 0.022) to be a significant predictor of MTA but not percent area of plaques (P = 0.375), percent area of tangles (P = 0.330) or percent area of Lewy bodies (P = 0.086). MTA on MRI had robust discriminatory power for distinguishing Alzheimer's disease from DLB and VCI in pathologically confirmed cases. Pathologically, it is more strongly related to tangle rather than plaque or Lewy body pathology in the temporal lobe. It may have utility as a means for stratifying samples in vivo on the basis of putative differences in pathology.

Temporal lobe atrophy on MRI in Parkinson disease with dementia: a comparison with Alzheimer disease and dementia with Lewy bodies.

OBJECTIVE: To investigate the extent of medial temporal lobe atrophy (MTA) on MRI in Parkinson disease (PD) with and without dementia compared with Alzheimer disease (AD) and dementia with Lewy bodies (DLB) and to determine whether MTA correlates with cognitive impairment in PD and PD dementia (PDD). METHODS: Coronal T1-weighted MRI scans were acquired from control subjects (n = 39) and patients with PD (n = 33), PDD (n = 31), DLB (n = 25), and AD (n = 31), diagnosed according to standardized clinical diagnostic criteria. Cognitive function was assessed using the Cambridge Cognitive Examination (CAMCOG), and MTA was rated visually using a standardized (Scheltens) scale. RESULTS: More severe MTA was seen in PDD (p = 0.007), DLB (p < 0.001), and AD (p < 0.001) vs control subjects. PD subjects had greater hippocampal atrophy than control subjects (p = 0.015) but less than subjects with DLB and AD, though not with PDD. MTA correlated with CAMCOG score and memory scores in the DLB group and with age in control, PDD, and AD groups. There were no correlations between MTA and cognitive impairment in PD, PDD, and AD. PDD and DLB had a similar profile of cognitive impairment and MTA. CONCLUSIONS: Medial temporal lobe atrophy (MTA) was seen in cognitively intact older subjects with Parkinson disease (PD) and was not more pronounced in Parkinson disease dementia (PDD). Alzheimer disease (AD) and, to a lesser extent, dementia with Lewy bodies (DLB) showed more pronounced MTA. Results suggest early hippocampal involvement in PD and that when dementia develops in PD, anatomic structures apart from the hippocampus are predominantly implicated. Greater hippocampal involvement in AD vs PDD and DLB is consistent with clinical, cognitive, and pathologic differences between the disorders.

Hippocampal atrophy, whole brain volume, and white matter lesions in older hypertensive subjects.

OBJECTIVE: To determine the potential role of whole brain atrophy, hippocampal atrophy, or both, and small vessel disease/white matter lesions as mechanisms underlying the cognitive impairment associated with hypertension. METHODS: Using MRI scanning the authors determined hippocampal volumes, whole brain volumes, and location and severity of white matter lesions, using Scheltens scale, in 103 hypertensive (166 +/- 8/88 +/- 7 mm Hg, 54 female) and 51 normotensive (132 +/- 12/74 +/- 7 mm Hg, 21 female) subjects age > or = 70 years. RESULTS: Compared to normotensive subjects, older hypertensive subjects had significantly smaller whole brain volumes (887 +/- 109 vs 930 +/- 97 cm3, p = 0.02) and nonsignificantly reduced hippocampal volumes (5.39 +/- 1.60 vs 5.67 +/- 1.80 cm3, p = 0.33). Hypertensive subjects had an increased burden of periventricular lesions: bands (p = 0.03), frontal caps (p = 0.08), occipital caps (p = 0.07), and total periventricular hyperintensities (p = 0.02). They also had higher scores in subcortical areas: frontal (p = 0.04), temporal (p = 0.03), and deep white matter areas (p = 0.05). A correlation was found between whole brain volumes and systolic blood pressure (r = -0.19, p = 0.02). No correlation was seen between whole brain volumes and white matter lesion burden. CONCLUSIONS: Moderate hypertension in non-impaired older subjects is associated with smaller whole brain volume and an increased burden of subcortical and periventricular white matter lesions.

NINDS AIREN neuroimaging criteria do not distinguish stroke patients with and without dementia.

OBJECTIVE: To determine the utility of the neuroimaging component within the National Institute of Neurological Disorders and Stroke (NINDS) Association Internationale pour la Recherche et l'Enseignement en Neurosciences (AIREN) criteria for vascular dementia for distinguishing between patients with and without dementia in the context of cerebrovascular disease. METHOD: One hundred twenty-five poststroke patients age > or =75 (27 with and 98 without poststroke dementia) from representative hospital-based stroke registers in the North East of England were evaluated using a 1.5 T MR scanner. The proportion of patients with and without poststroke dementia meeting the imaging component of the NINDS AIREN criteria was determined, and hippocampal atrophy (measured using the Schelten scale) was compared between the two groups. RESULTS: There were no significant differences between the patients with and without poststroke dementia on any criteria of the imaging parameters within the NINDS AIREN criteria. In addition, there were no significant differences in the number or size of cortical or subcortical infarcts between the two groups, with 13 patients without dementia having cortical infarcts >50 mm. Patients with dementia had greater hippocampal atrophy (right: Mann-Whitney U test, Z = 2.5, p = 0.01; left: Mann-Whitney U test, Z = 2.5, p = 0.01). CONCLUSION: The neuroimaging component of the NINDS AIREN criteria does not distinguish between older patients with and without poststroke dementia.

The application of serial MRI analysis techniques to the study of cerebral atrophy in late-onset dementia.

We have used a serial MR image analysis technique previously developed for studies of cerebral atrophy in early-onset dementia and applied it to a study of late-onset dementia patients with images acquired using a different scanner and scan sequence. Validation and optimisation tests showed that with only small changes to key analysis parameters the technique can successfully be applied to previously untested data with dissimilar image characteristics. The overall accuracy in estimation of cerebral atrophy using the technique was determined to be between 2 and 4 ml (1sigma) depending on the conditions during image acquisition. By comparing the results of alternative registration techniques we demonstrate the potential of using of fully automated 9 DOF image registration as an effective and efficient means of correcting for scanner pixel size variations, even in the presence of significant cerebral atrophy. Applied to the late-onset dementia study, patients were found to have significantly increased mean atrophy rates (p<0.001) compared to controls. In general the analysis technique is shown to be a robust, accurate and transferable tool of potential value for future studies of dementia and related neuro-degenerative disorders.