Are levels of digestive enzyme activity related to the natural diet in passerine birds?

Digestive capabilities, such as the rates nutrient hydrolysis and absorption, may affect energy intake and ultimately feeding behavior. In birds, a high diversity in gut biochemical capabilities seems to support the existence of a correlation between the morphology and physiology of the intestinal tract and chemical features of the natural diet. However, studies correlating the activity of digestive enzymes and the feeding habits at an evolutionary scale are scarce. We investigated the effect of dietary habits on the digestive physiological characteristics of eight species of passerine birds from Central Chile. The Order Passeriformes is a speciose group with a broad dietary spectrum that includes omnivorous, granivorous and insectivorous species. We measured the activity of three enzymes: maltase, sucrase and aminopeptidase-N. Using an autocorrelation analysis to remove the phylogenetic effect, we found that dietary habits had no effect on enzymatic activity. However, we found that granivorous and omnivorous species had higher levels of disaccharidase activities and insectivores had the lowest. The major difference in enzymatic activity found at the inter-specific level, compared to the reported lower magnitude of enzyme modulation owing to dietary acclimation, suggests that these differences to some extent have a genetic basis. However, the lack of a clear association between diet categories and gut physiology suggested us that dietary categorizations do not always reflect the chemical composition of the ingested food.

Intestinal enzymes during malnutrition & infection in rabbits.

BACKGROUND & OBJECTIVES: Malnutrition plays an important role in the intestinal absorption of nutrients. However, reports are not consistent whether intestinal enzymes are decreased in the presence of malnutrition. It is also not clear whether simultaneous presence of malnutrition and infection adds to the problem of malabsorption of nutrients. The aim of the present study was to determine intestinal functions in terms of concentrations of disaccharidase enzymes during diarrhoea and protein energy malnutrition. METHODS: Concentrations of three disaccharidase enzymes, namely maltase, sucrase and lactase were measured in nine energy-restricted and five control rabbits during diarrhoea induced by rabbit diarrhoeagenic Escherichia coli (RDEC-1). Malnutrition was achieved in the rabbit model by feeding the animals for 30 days with half the amount of food fed to well-nourished control rabbits. Both the energy-restricted and the control groups were challenged by RDEC-1. Diarrhoea occurred on day 1-7 after administration of the strain. After onset of diarrhoea, both groups of rabbits were sacrificed and their intestinal mucosa was examined to determine the concentration of lactase, maltase and sucrase. RESULTS: The energy-restricted animals and controls did not differ significantly for concentrations (units/mg proteins) of lactase (0.65 +/- 0.28 vs 0.56 +/- 0.17 ), maltase (6.20 +/- 2.70 vs 6.47 +/- 1.90) and sucrase (5.42 +/- 2.30 vs 5.13 +/- 1.40) measured during acute infectious diarrhoea. INTERPRETATION & CONCLUSION: The results suggested that the enzymatic functions of the intestinal brush border were not statistically different during diarrhoea among malnourished rabbits compared with their well-nourished counterparts.

Effects of malnutrition on the digestive enzymes of the large bowel of young rhesus monkeys.

The aim of the present study was to investigate the effect of mild-to-moderate protein-energy malnutrition (PEM) and rehabilitation on the digestive enzymes of the large bowel in young rhesus monkeys. The presence of these enzymes has already been reported in the large bowel by many authors. The activities of the digestive enzymes, i.e. lactase, sucrase, maltase, trehalase, glucoamylase, leucine aminopeptidase, alkaline phosphatase and gamma-glutamyl transpeptidase, from different parts of the large bowel were determined in 6 controls, 6 PEM and 6 rehabilitated young rhesus monkeys. These monkeys had been used to study the effect of malnutrition on the small intestine and the results have already been published. There was a significant decrease in the sucrase in the ascending colon (p < 0.05); maltase in all the parts of the large bowel (p < 0.05); and glucoamylase activities (p < 0.05) in the caecum segment of the large bowel in the PEM group. The activity of other enzymes, i.e. lactase, trehalase, alkaline phosphatase, gamma-glutamyl transpeptidase and leucine aminopeptidase, was unaffected in the PEM group. The changes in the enzyme activities recovered on rehabilitation of 21 weeks. The result of this study suggest that even mild-to-moderate malnutrition affects the enzyme activity of the large bowel, which recovers on rehabilitation.

Age related effects of organochlorine insecticide lindane on intestinal brush border membrane in rats.

The effect of oral administration of lindane (gamma-HCH) has been studied on the intestine in 10-day, 20-day and 100-day old rats. In 10 day-old suckling pups exposed to lindane, there was a significant decrease in the activities of sucrase (29%), lactase (20%) and that of alkaline phosphatase (24%) compared to control. Sialic acid content of the brush borders was significantly decreased (29%) in 10-day old as well as in 20- and 100-day old rats (20 and 25% respectively), while fucose content of the membranes was significantly enhanced in all the age groups upon pesticide treatment. Among the brush border lipids, cholesterol content was significantly increased in all the age groups studied, the maximum increase of 35% being observed in 10-day-old rats. Membrane phospholipids were also increased in 20- and 100-day old animals (22% each) on lindane exposure. The present studies indicated that brush border membranes of suckling rat intestine were more susceptible to pesticide induced changes compared to older animals.

Effect of alcohol dependence on the levels of duodenal disaccharidases in human subjects.

BACKGROUND: The aim of the study was to detect the duodenal enzyme activity in patients of alcohol dependence and to compare with non-alcoholic patients of non-ulcer dyspepsia. METHODS: Disaccharidases (lactase, sucrase, maltase) were estimated in 20 non alcoholic patients of non-ulcer dyspepsia and 20 alcoholics admitted to the drug de-addiction and treatment centre of PGIMER, Chandigarh, India. RESULTS: No significant influence of alcohol on enzyme levels in patients of alcohol dependence when compared to patients of non-ulcer dyspepsia was observed. However, a significant decrease in lactase level was noted in patients consuming more than 125 gm/day of alcohol. CONCLUSION: Amount of consumption of alcohol showed decrease in lactase enzyme, but not in maltase and sucrase. There was no effect of duration of alcohol consumption on dissacharidases in the two groups.

Some biochemical changes in heme synthesis in iron deficiency.

Some enzymes and intermediates of heme synthesis were determined in blood and urine of 26 women with severe iron deficiency anemia (IDA). Erythrocyte free protoporphyrin was almost doubled and delta-aminolevulinate dehydrase significantly raised. But urinary excretion of delta-aminolevulinic acid and reticulocyte ferrochelatase were significantly reduced in iron deficiency anemia. Hence these could serve as useful indices of iron deficiency and consequent anemia.

Effect of ischemia/reperfusion on intestinal brush border membrane lipid composition, fluidity and enzyme activities.

Oxygen-derived free radicals are known to be generated during ischemia/reperfusion injury and biomembranes are the prime target of these active species. In order to study the effect of in vivo generated free radicals on intestinal mucosal membrane, brush border membranes (BBM) were isolated from rat small intestine after subjecting to ischemia (I) and ischemia/reperfusion (I/R) injury and their lipid composition and marker enzyme activity were compared with BBM prepared from control animals. No significant alteration in the lipid composition of BBM was observed after I or I/R as compared to control. Membrane fluidity measurements showed that I/R increased the fluidity of BBM. Activity of alkaline phosphatase, one of the marker enzymes for BBM was reduced by I or I/R whereas activity of another BBM enzyme, sucrase was not altered. The decrease in alkaline phosphatase activity was more after reperfusion. In vitro fluidization of BBM using benzyl alcohol indicated that the inactivation of alkaline phosphatase was not due to change in fluidity. These results suggest that free radicals generated during I/R inactivate BBM alkaline phosphatase partially without altering the membrane lipid composition.

Expression of brush border enzymes in ethanol fed rat intestine.

The effect of feeding ethanol daily for 40 days was studied on various brush border enzymes in rat intestine. Brush border alkaline phosphatase (AP), lactase, gamma-glutamyltranspeptidase (gamma-GTP), p-nitrophenyl (PNP)-beta-D-galactosidase (P < 0.01) and sucrase (P < 0.001) were significantly enhanced while leucine aminopeptidase and PNP-beta-D-glucosidase activities were unaltered in ethanol fed rats compared to the controls. Kinetic studies revealed that an increase in Vmax together with a decrease in affinity in case of gamma-GTP and an increase in Vmax for AP and sucrase were responsible for the observed stimulation of enzyme activities in ethanol administered rats. Significant changes in enzyme activities were observed in different populations of enterocytes along the crypt-villus unit in the ethanol fed animals. These observations suggest that ethanol feeding modifies the brush border enzymes in rat intestine but the underlying mechanisms seem to be distinct in differentiating enterocytes.

Jejunal disaccharidases in protein energy malnutrition and recovery.

The jejunal disaccharidases, sucrase, maltase and lactase, were determined in jejunal biopsies obtained from 43 malnourished children and 10 controls. In the study group, 63% were girls and 93% had severe malnutrition. Lactase activity was significantly reduced in third and fourth degree malnutrition (p < 0.05 and p < 0.005, respectively), but maltase activity was significantly reduced only in the fourth degree malnutrition (p < 0.01). After recovery, maltase and sucrase activities showed a marginally significant increase (p = 0.06), where lactase showed no significant increase (p > 0.05). We conclude that jejunal disaccharidase activity decreases significantly with increasing severity of malnutrition, lactase being the most severely affected and the last to recover.

Alterations in rat intestinal sucrase and alkaline phosphatase activities in alloxan induced experimental diabetes.

Rat intestines revealed a significant loss of proteins after seven days of alloxan induced diabetes. The data suggested the presence of two forms of alkaline phosphatase (ALP) in normal rat intestines. Along with the loss of proteins from the intestines during diabetes, a form of ALP which appears to be loosely bound to the intestine is also flushed out. Total brush border membrane (BBM) proteins are relatively preserved from such leaching effect of alloxan induced diabetes. Thus, sucrase and another form of ALP which appears to be strongly bound to the BBM are flushed out at a slower rate as compared to the other intestinal proteins and loosely bound soluble ALP. BBM preparations from diabetic rat intestines showed lower ratios for BBM/intestinal homogenate sucrase or ALP activity/mg proteins as compared to the normal control rats. Such ratios, therefore, misdepict the purity as low for the BBM from diabetic rats which is merely because of the decreased contents of proteins in the intestinal homogenate during alloxan-induced acute experimental diabetes.

Kinetic characteristics of soluble and brush border alkaline phosphatase and sucrase activities in developing rat intestine: effect of hormones.

Suckling rat intestine contains 35 and 65% of the cytosolic and membrane-bound alkaline phosphatase (AP) activities. The corresponding values for sucrase were 20 and 80% respectively. The amount of the soluble enzymes was reduced to 7-11% in adult rat intestine. Administration of cortisone, thyroxine or insulin to suckling animals induced adult type distribution of the enzymes. There were apparent differences in kinetic characteristics of soluble and brush border enzymes, but the kinetic properties of the normally developed and hormone-induced AP and sucrase were essentially similar. This suggested identical nature of these enzymes under these conditions. A biphasic Arrhenius plot was obtained for AP in weaned and hormone injected pups with a break point around 18 degrees C, while the soluble enzyme yielded a monophasic curve (Ea = 8-11 kcal/mole). Arrhenius plot for sucrase was monophasic in the suckling, hormone-injected and adult rat intestine (Ea = 8.3-15.1 kcal/mole). Membrane-bound enzymes were generally labile, while soluble enzyme activities were stable to heat treatment (sucrase at 50 degrees C and AP at 60 degrees C) in various experimental groups.

Some properties of monkey intestinal sucrase.

A detergent solubilised sucrase from monkey small intestine has been purified 388-fold to gel electrophoretic homogeneity with an overall recovery of 36%. The molecular weight of the enzyme was 263 kDa by gel filtration. Electrophoresis in the presence of SDS indicates that the enzyme is a hetero-dimer. Mixed substrate inhibition studies and inhibition by PCMB and Tris suggest the presence of two catalytically active sites in the form of maltase and sucrase with isomaltase activity being common to both sites. Polyclonal antiserum against the purified enzyme showed a single continuous precipitin line with the purified antigen.

Intestinal glucoamylase & other disaccharidases in children with protracted diarrhoea.

Brush border lactase, sucrase and glucoamylase activities were assessed in jejunal mucosal biopsy specimens from 34 children (median age 11 months; range 1.5-38) having protracted diarrhoea with failure to thrive and 8 well nourished children with normal jejunal mucosal histology (median age 10.2 months; range 2-37). All enzymes showed progressive decrease in activity which was directly in relation to increasing degree of mucosal injury (P less than 0.002). Lactase was significantly reduced even in patients with protracted diarrhoea and normal mucosa (P less than 0.05). Glucoamylase and sucrase were significantly reduced only in the presence of mucosal injury (P less than 0.01). Our data suggest that most children with protracted diarrhoea may not tolerate lactose containing feeds and may need lactose-free diets preferably based on starch. A small number of children with protracted diarrhoea, who have severe mucosal injury may not be able to handle even starch and may require diets based on short chain glucose polymers. The findings of this study, need to be corroborated with well-controlled metabolic balance studies.

Efecto de la ingestión de pan integral sobre la actividad disacaridasica intestinal en ratas / Effects if ingestion of whole-wheat bread on intestinal disacharidase activity in rats

Se realizó un experimento para evaluar el efecto de la ingestión de pan integral sobre la actividad disacaridásica intestinal. Se utilizó un total de 21 ratas macho, las cuales se agruparon según: a) dieta control con caseína más metionina, b) dieta con blanco, y c) dieta con pan integral. Despúes del periodo experimental de 10 días, se determinó la actividad específica de lactasa, mitasa, sacarasa y trealasa en distintos niveles de localización en la microvellosidad. Todas las enzimas presentaron una disminución significativa (p<0,01) de su actividad en la fracción luminal en las ratas alimentadas con pan integral. Sólo la lactasa y la maltasa mostraron una disminución de su actividad (p<0.01) en la fracción de membrana para dicha dieta. La fracción enterocitaria no mostró diferencia cuando se comparó con la dieta de pan blanco. En todos los nivles de localización la actividad disacaridásica fue mayor en la dieta control (p<0.01). Los resultados obtenidos sugieren que el efecto por "arrastre mecánico" de la fibra dietética contenida en el pan integral es el fundamental en la interacciòn fibra-actividad disacaridásica y que, por tanto, su presencia en el intestino no afecta sensiblemente la biosíntesis de dichas enzimas en el enterocito

Atividade dissacaridásica intestinal da esquistossomose mansônica: estudo evolutivo em camundongos com diferentes cargas de infestaçäo / Intestinal activity of disaccharides in schistosomiasis mansoni: study of the course in mice with different loads of infestation

A esquistossomose mansônica compromete vários órgäos, sendo o intestino e o fígado os mais agredidos. Com a intençäo de verificar o comprometimento do intestino delgado, dependente da intensidade e do tempo de infecçäo pelo Schistosoma mansoni, analisou-se a atividade das dissacaridases - lactase, sacarase e maltase - em 112 camundongos, distribuídos em 3 grupos: grupo I - controle, grupo II - infestado com 30 cercárias, grupo III - infestado com 60 cercárias. Observou-se uma diminuiçäo da atividade lactásica, sacarásica e maltásica do intestino delgado, decorrente da infestaçäo esquistossomótica, do tempo de infestaçäo e da alteraçäo entre ambos. O íleo é o segmento que demonstrou maior sensibilidade a esquistossomose, tendo uma diminuiçäo das suas dissacaridases a partir da fase inicial de infestaçäo. Opostamente, o jejuno só mais tardiamente mostra essas alteraçöes, exceto em relaçäo a lactase. Detectou-se um aumento da atividade dissacaridásica, inclusive para a lactase, em todos os grupos, com a evoluçäo etária dos animais, quantitativamente menor nos infestados. Cargas de 30 e 60 cercárias devem ser consideradas do mesmo porte, pois produziram reduçäo semelhante na atividade dissacaridásica

Estudio comparativo del efecto de acetato de hidrocortisona y la prednisolona sobre la actividad de algunas enzimas intestinales / Comparative study of hydrocortisone acetate and prednisolone effect on some intestinal enzymes activites

Se estudia el efecto que produce el acetato de hidrocortisona y la prednisolona en ratas de 12 días de nacidas que habían sido previamente inyectadas durante 3 días consecutivos con una dosis de 50 mg/kg de peso. Se observó que el efecto del acetato de hidrocortisona fue más intenso que el de la prednisolona al incrementar la actividad de la sacarasa y la leucina aminopeptidasa; y que el efecto de la prednisolona fue más intenso que el del acetato de hidrocortisona al incrementar la actividad de la fosfatasa alcalina y al disminuir la ß galactosidasa ácida y la catepsina D. Además, ninguna de las dos hormonas provocó cambio en la lactato deshidrogenasa. Se concluye que aunque el efecto de ambas hormonas es diferente desde el punto de vista cuantitativo, la prednisolona es capaz de producir los cambios de los niveles enzimáticos de forma similar a los que provoca el acetato de hidrocortisona