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In vitro and in vivo investigations of carbohydrates with different digestibilities for improved satiety and metabolic healthAnna MR Hayes (8477520) 01 March 2021 (has links)
<p>Obesity and nutrition-related
non-communicable diseases continue to be major challenges that are increasing
in severity worldwide. Science-centered carbohydrate dietary strategies may be
a viable approach to help address such challenges. Recent reports from our
laboratory indicate that certain carbohydrates with slow digestion profiles
have the ability to trigger the gut-brain axis and reduce food intake and to
slow gastric emptying and potentially affect appetite. Slow carbohydrate
digestion may have other impacts on energy metabolism that have not been
explored. In the current investigations, we sought to better understand the
delayed gastric emptying profile of pearl millet-based foods as well as to
understand how altering carbohydrate digestion rate impacts substrate utilization
for energy.</p>
<p>In the first study, the
physical breakdown of pearl millet couscous particles in a simulated gastric
environment (Human Gastric Simulator) was studied compared to wheat couscous
matched in particle size, and select physicochemical properties of each type of
couscous were characterized. Because we previously showed that pearl millet
couscous had a marked delay in gastric emptying compared to white rice, boiled
potatoes, and pasta in a human study in Mali, the objective of the first investigation
was to test the hypothesis that pearl millet couscous was more resistant to
breakdown in the stomach than wheat couscous and would take longer to empty.
Our findings indicated that pearl millet couscous instead broke down into
smaller, more numerous particles than wheat couscous. However, pearl millet had
a slower starch hydrolysis property compared to wheat couscous per unit surface
area. Pearl millet also had a smaller amylose chain length (839-963 DP) compared
to wheat (1225-1563 DP), which may enable a denser packing of millet starch
molecules that hinders hydrolysis. We also visually observed that the pearl
millet particles formed a paste while breaking down that could reasonably
generate viscosity in the stomach to potentially delay gastric emptying. </p>
<p>Based off the findings
from simulated gastric digestion, we next conducted a human study (<i>n</i>=14)
in the U.S. to test the hypothesis that pearl millet-based foods (couscous –
commercial and self-made, thick porridge) would reduce glycemic response, increase
satiety, and delay gastric emptying compared to wheat couscous and white rice.
We complemented this human study with additional <i>in vitro </i>work using an
advanced gastrointestinal digestion system (TIMagc) to determine if the
viscosity of pearl millet couscous particles as they were breaking down in the
stomach was contributing to a decrease in gastric emptying. Our findings indicated
that all the pearl millet-based foods and wheat couscous had lower overall
glycemic response than white rice, but only the self-made millet couscous
showed higher satiety through subjective appetitive response ratings.
Surprisingly, there were no differences in gastric emptying among the foods.
Additionally, the half-emptying times for these foods were all ~3 h, which is similar
to the comparably low half-emptying times observed for white rice, boiled
potatoes, and pasta in the previous Mali study. We now hypothesize that there
may be diet-induced changes in gut-brain axis signaling when slowly digestible
carbohydrates are consumed repeatedly over time, perhaps through modulating the
number or sensitivity of small intestinal L-cells. We also found that millet
couscous did not exhibit high viscosity in the TIMagc, suggesting that
viscosity was not impacting its rate of gastric emptying. We conclude that at
least some pearl millet-based foods possess a slow digestion property that may
act to trigger the gut-brain axis or ileal brake to increase feelings of
satiety or slow gastric emptying, but the discrepancy between U.S. and Malian
populations requires further study. </p>
<p>In the final
investigation, we examined how altering carbohydrate digestion affected partitioning
of carbohydrate versus fat for oxidation as well as the efficiency of switching
oxidation between these two substrates (termed “metabolic flexibility”) in
mice. Metabolic flexibility has been associated with good health related to
decreased adipose tissue in the body and improved insulin sensitivity and may
have implications on weight management. Carbohydrate digestion was adjusted by:
(1) testing mice that lacked a complete set of enzymes by knocking out
maltase-glucoamylase (Mgam; null) for moderating starch digestion versus
testing wild-type mice; (2) using diets in these two groups of mice to moderate
starch digestion that had different levels of resistant starch (53%, 35%, and
18%), had only raw corn starch or sucrose, or were high in fat; and (3)
providing a supplement of fungal amyloglucosidase (AMG) to the mice treatment
groups to increase starch digestion. Respiratory exchange ratio (RER) was
measured through indirect calorimetry and mathematical modeling was used to
characterize the diurnal shifts in RER (sine equation) as well as carbohydrate
versus fat oxidation and metabolic flexibility (percent relative cumulative
frequency [PRCF] with Weibull and Mixed Weibull Cumulative Distribution
functions). Our results suggest that null mice lacking Mgam had somewhat
increased metabolic flexibility than wild-type mice despite exhibiting minimal
to no effects on carbohydrate oxidation. Intriguingly, the raw corn starch diet
increased fat oxidation and generally promoted metabolic flexibility, although
it did not increase carbohydrate oxidation relative to the other
carbohydrate-predominant diets. Increasing carbohydrate digestion through AMG
supplementation increased carbohydrate oxidation, and generally prompted
earlier shifts to carbohydrate oxidation than without AMG supplementation.
These findings provide a basis for better understanding the metabolic
consequences of altering carbohydrate digestion and establish novel tools that
can be utilized in future investigations. Overall, we propose that moderating
carbohydrate digestion provides the ideal combination of balancing carbohydrate
and fat oxidation while promoting metabolic flexibility. </p>
<p>In conclusion, a slow
digestion property may enable some types of pearl millet to trigger the ileal
brake and gut-brain axis feedback systems to decrease glycemic response and increase
satiety. Moreover, consuming carbohydrates with slow digestion may optimize
substrate utilization for energy by the body. In addition to triggering the
ileal brake and gut-brain axis, modulating carbohydrate digestion to more
effectively switch between carbohydrate and fat for oxidation may be beneficial
for weight management and metabolic disease prevention.</p>
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Regulation of growth and nutrient digestibility by supplemental myo-inositol and luteolin in pigs and chickensTobi Zachariah Ogunribido (18509157) 07 May 2024 (has links)
<p dir="ltr">Newborn animals undergo a lot of early-life stress that heavily impact on their long-term growth, performance, and welfare. Typically, the stress would indirectly interfere with the capacity of these neonates to utilize dietary nutrients and consequently impact tissue growth and development. In piglets, weaning is a stressful situation characterized by disruption of intestinal epithelial cell development which causes poor digestion of solid feed and a negative impact on absorption of nutrients especially in the post-gastric region. In addition, weaning in piglets could cause an increase in cellular assault by reactive oxygen species thereby potentially causing gut leakiness and paracellular loss of nutrients along the intestinal tract. In broiler chickens, access to feed may take up to 72 h following hatching which may affect their gut development as well as their gut microbiota. After the first feed ingestion, there is a sharp increase in the gut microbiota which triggers an increase in the development of the immune system as well as the gut. There is continuous attention on the strategies and nutritional interventions to mitigate or ameliorate the adverse effects of early life stressors in these food animals, especially in broiler chickens and piglets. In the studies described in this dissertation, myo-inositol (purely supplemented or phytase-induced) and luteolin were tested as nutritional strategies to mitigate the effects of early-life stressors on growth and the potential mechanisms by which myo-inositol and luteolin regulate growth were investigated.</p><p dir="ltr">In study I, the effect of myo-inositol on growth in 128 postweaning piglets fed protein-deficient corn-soy diets was tested. There were 4 dietary treatments in a randomized complete block design with body weight as the blocking factor. The treatments consisted of 1 positive control (PC) diet formulated to meet all the nutrient requirements of the piglets with a 20% crude protein (CP); the remaining 3 diets were the negative control (NC) diets with a 3% reduction in CP, a 2 g/kg myo-inositol supplemented negative control diet (NC+INO), and phytase (3,000 FTU/kg) supplemented negative control (NC+PHY) diet. The results showed that phytase enhanced the apparent total tract digestibility (ATTD) of P in the weanling pigs. Myo-inositol supplementation in a protein-deficient diet improved (P < 0.05) porcine plasma myo-inositol concentration while an in vitro myo-inositol incubation with intestinal epithelial cells increased the expression of genes that encode for Claudin-1, Claudin-3, Claudin-4, ZO-1, NaPiIIb, GLUT2, and SLC7A2. The in vitro analysis of tight junction integrity in the IPEC-J2 cells indicated by the transepithelial electrical resistance and FITC-Dextran permeability showed an enhancement in response to myo-inositol treatment. Although the in vivo study found that myo-inositol did not improve growth performance or ATTD, the in vitro myo-inositol enhanced markers of gut health and function.</p><p dir="ltr">In study II, the effect of myo-inositol on the growth of broiler chickens was tested. In this study, there were 6 experimental treatments based on two dietary protein levels (PC and NC) and three supplement types (BASAL, INO, and PHY) resulting in a 2 x 3 factorial arrangement in a completely randomized design. A total of 384 broiler chickens comprising 6 treatments with eight replicates per treatment and 8 birds per replicate were used. The birds were fed a common starter diet for the initial 7 days after they arrived at the poultry unit followed by a 14-day trial. The protein-deficient diet decreased the feed efficiency of the birds. Phytase addition increased (P < 0.05) the apparent ileal digestibility (AID) and ATTD of P and Ca in both PC and NC groups. The jejunal gut morphology was enhanced by supplemental phytase as indicated by an increase in villus height and the ratio of the villus height-to-crypt depth, coupled with an increase in serum myo-inositol concentration caused by both myo-inositol and phytase. In conclusion, myo-inositol showed a differential influence on growth performance, nutrient digestibility, and gut morphology.</p><p dir="ltr">In study III, the effects of luteolin on weanling pigs and IPEC-J2 cells were examined. A total of 48 piglets were randomly allotted to two dietary treatments consisting of a control group and a luteolin (LUT)-supplemented dietary group for a 4-week trial. A weekly assessment of the growth performance and expression of specific proteins in the jejunal mucosa was performed. In each dietary group, 8 piglets were slaughtered at weeks 1, 2, and 4 postweaning to collect blood, jejunal and ileal mucosa, and tissues. Luteolin supplementation numerically improved the ADG and G:F of the pigs. Luteolin feeding altered the jejunal and ileal gut morphology with increased villi height (P < 0.05) and villus height-to-crypt depth ratio (VCR, P < 0.05) in the jejunum and decreased crypt depth in the ileum. The effect of luteolin on IPEC-J2 global proteome and phosphor-proteome showed that luteolin could potentially improve intestinal barrier integrity by enhancing the abundance of proteins important in cell growth and survival. </p><p dir="ltr">In summary, dietary supplementation with myo-inositol and luteolin could regulate growth and nutrient digestibility in broiler chickens and weanling pigs by enhancing the integrity of intestinal cells and facilitating the expression of nutrient transporters that are significant in the uptake of nutrients across the lining of the gastrointestinal tract. Phytase supplementation improves the P release from phytate in the diets thereby alleviating its loss.</p>
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Nutrição do tomateiro e a sua influência na preferência para abrigo, alimentação e oviposição de Bemisia tabaci (GENN.) biótipo B / Nutrition of the tomato and her influence in the preference for shelter, feeding and oviposition of Bemisia tabaci (Genn.) biotype BOLIVEIRA, Marcos Fernandes 26 February 2008 (has links)
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Previous issue date: 2008-02-26 / Bemisia tabaci biotype B presently constitutes a great threat not only for the
tomato crop but to several other cultures. The objective of this research was to evaluate the
influence of the nutrition of tomato in the resistance induction for shelter, feeding and
oviposition of B. tabaci biotype B. The experiments were driven in Escola de Agronomia e
Engenharia de Alimentos (EA/UFG), Goiânia, Goiás, Brasil. Three experiments were
accomplished outdoors in temperature conditions, humidity and natural photoperiod. In
the first different sources of nitrogen were tested, in the second different ratios
nitrogen/potassium and in the third party different associations between corrected soil and
earthworm manure. Each experiment was subdivided in: with choice chance and without
chance of choice of the insect, the first one was carried out on randomized blocks design
and the second one completely randomized design. Each treatment had four replications,
with one plant per pot. In the first experiment the treatments used were: corrected soil
(without addition of fertilizers); potassium saltpeter; urea; phosphate monoamonic; nitrate
of calcium; sulfate of ammonium; chicken manure; bone flour; castor oil plant pie;
composed organic; and earthworm manure. In the second experiment the ratios were
compared N/K: 1/1; 2/1; 4/1; 8/1; 1/2; 1/4; and 1/8. In the third experiment the associations
corrected soil were compared + earthworm manure: 100% + 0%; 80% + 20%; 60% + 40%;
40% + 60%; 20% + 80%; 0% + 100%. Five evaluations on the observation of the behavior
of B. tabaci biotype B in relation to the feeding preference and shelter were accomplished:
3, 27, 51, 75 and 99 hours after the insect infestation. Leaves were collected at four days
after the insect infestation, and appraised in laboratory for oviposition analysis. The
different sources of nitrogen, ratios nitrogen/potassium, and associations between corrected
soil and earthworm manure used in the tomato fertilization did not induce any effect at the
feeding or oviposition of B. tabaci biotype B behavior. / A Bemisia tabaci biótipo B constitui-se atualmente uma grande ameaça não só
a cultura do tomateiro mais a diversas outras culturas. O objetivo dessa pesquisa foi avaliar
a influência da nutrição do tomateiro na indução de resistência para abrigo, alimentação e
oviposição de B. tabaci biótipo B. Os experimentos foram conduzidos na Escola de
Agronomia e Engenharia de Alimentos (EA/UFG), Goiânia, Goiás, Brasil. Foram
realizados três experimentos ao ar livre em condições de temperatura, umidade e
fotoperíodo naturais. No primeiro foram testadas diferentes fontes de nitrogênio, no
segundo diferentes relações nitrogênio (N)/potássio (K) e no terceiro diferentes associações
entre solo corrigido e esterco de minhoca. Cada experimento foi subdividido em: com
chance de escolha e sem chance de escolha do inseto, para o primeiro foi utilizado o
delineamento de blocos casualizados e para o segundo o delineamento inteiramente
casualizado. Cada tratamento foi composto por quatro repetições, com uma planta por
vaso. No primeiro experimento os tratamentos utilizadas foram: solo corrigido (sem adição
de adubos); salitre de potássio; uréia; fosfato monoamônico; nitrato de cálcio; sulfato de
amônio; esterco de galinha; farinha de osso; torta de mamona; composto orgânico; e
esterco de minhoca. No segundo experimento foram comparadas as relações
nitrogênio/potássio: 1/1; 2/1; 4/1; 8/1; 1/2; 1/4; e 1/8. No terceiro experimento foram
comparadas as associações solo corrigido + esterco de minhoca: 100% + 0%; 80% + 20%;
60% + 40%; 40% + 60%; 20% + 80%; 0% + 100%. Para observação do comportamento de
B. tabaci biótipo B em relação à preferência alimentar e abrigo foram realizadas cinco
avaliações às 3, 27, 51, 75 e 99 horas após a infestação dos insetos. Para a análise da
oviposição, foram coletadas folhas quatro dias após a infestação dos insetos, e avaliadas
em laboratório. As diferentes fontes de nitrogênio, relações nitrogênio/potássio e
associações entre solo corrigido e esterco de minhoca, utilizadas na adubação de plantas de
tomateiro, não foram capazes de induzir a expressão de nenhum efeito inibidor de
alimentação, abrigo ou oviposição de B. tabaci biótipo B.
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