Changes In Digestive Enzymes Research Articles

Changes in digestive enzymes and nutritional ontogeny reserves in newly hatched Pacific pygmy octopus, Paroctopus digueti

In this study, changes in digestive physiology and nutritional reserve content during the early stages of the Pacific pygmy octopus, Paroctopus digueti, were examined. Body growth, biochemical composition (soluble protein and glycogen concentrations) in the digestive gland and arm muscle, hepatosomatic index, as well as lipases and proteases (acid and alkaline) activities were determined every two days up until 14 days after hatching. Newly hatched octopuses were obtained in the laboratory, from the eggs of a female that spawned in the wild and were kept in individual chambers and fed fresh crab meat. A significant decrease in soluble protein was observed in both, the digestive gland (8 days after hatching) and the arm muscle (2–4 days after hatching). Thereafter, soluble protein gradually increases in digestive gland whereas, in the arm muscle, afterward a significant increase at 6 days after hatching, a decreasing pattern until 14 days after hatching was noticed, possibly due to the start of exogenous feeding. In arm muscle, 2 days after hatching the glycogen showed a peak with subsequent marked fluctuations up to 14 days after hatching, indicative of the complete use of internal nutritional reserves and dependence on exogenous feeding at this time. Higher lipase activity was observed 2 days after hatching, with a significant decrease occurring between 6 and 14 days after hatching. Acid protease activity increased between 6 and 14 days after hatching, while alkaline protease activity remained stable during the developmental period, with a peak occurring 8 days after hatching. These results contribute to the further understanding of this critical period of transition from endogenous to exogenous feeding that takes place between 6 and 8 days after hatching and may be useful in developing effective feeding schemes employing natural or formulated foods for this species.

Fishmeal replacement and its effects on nutrition and the physiology of Penaeus vannamei shrimp juveniles

The replacement of fishmeal with plant protein sources has been studied in Penaeus vannamei. However, it has only been studied from the point of view of protein replacement, forgetting the integral role that fishmeal plays in the nutrition of shrimp. This study aimed to determine if a supplement of dietary phosphorus can sustain the fishmeal replacement by a blend of plant protein feedstuffs, with betaine and tauren as attractants and still supporting homeostasis, growth, digestive enzymes, and lipid-soluble antioxidant systems at normal levels in juveniles of P. vannamei. A standard feed (25% fishmeal) for juvenile P. vannamei was partially replaced with a mix of plant ingredients (soybean and canola paste, soy protein concentrate, and wheat meal). These feedstuffs were supplemented with amino acids (MET, LYS, TAU) plus microencapsulated exogenous phytase, betaine, and dicalphosphate. P. vannamei juveniles (2.56 g) were maintained in 100 L fiber tanks for 70 days. Biomass was significantly affected by the treatments (P < 0.05), being better as the fishmeal was replaced in the diet and comparable to commercial feed. No significant changes were observed in blood parameters. Muscle superoxide dismutase activity was significantly affected by the diets (P < 0.05). There were adaptive changes in digestive enzymes, and homeostasis remained stable. Fishmeal replacement may depend on supplementation with taurine and soluble phosphorus, not only for performance but flesh quality, and here, the shear strength of the shrimp muscle remained within the acceptable value (69-81 mJ).

АКТИВНОСТЬ ДУОДЕНАЛЬНЫХ ФЕРМЕНТОВ В ПОСТЭМБРИОНАЛЬНЫЙ ПЕРИОД ОНТОГЕНЕЗА ЦЫПЛЯТ-БРОЙЛЕРОВ КРОССА «СМЕНА 9» ПРИ РАЗНОМ УРОВНЕ ПРОТЕИНА В РАЦИОНЕ

The work has been dedicated to study of age changes in digestive enzymes and alkaline phosphatase activ- ity in duodenum tissues in “Smena 9” cross broilers in ontogenesis postembryonic period with changes of raw protein level in start feed. The results of poultry intestine tissue gomogenate investigation at this stage have shown amylase, lipase and alkaline phosphatase activity decreasing and also protease activity increasing comparing these traits in day age. Raw pro- tein content increasing in feed by 1.5% in the first 14 days of raising has increased intestine proteases activity in 21–35 days in comparison with the control group. Therefore first two weeks of raising are one of the critical periods in broiler ontogenesis and feeding and maintaining disturbances in this period influence sufficiently the next broiler development stages.

Symbiotic microbiome and metabolism profiles reveal the effects of induction by oysters on the metamorphosis of the carnivorous gastropod Rapana venosa

Most marine mollusks have a pelagic larval phase, and they need to undergo metamorphosis to develop into adults. Metamorphosis is affected by many factors, including abiotic factors such as temperature, salinity and illumination as well as biological factors such as food and microorganisms. In our previous study, we found that the metamorphosis of Rapana venosa requires induction by juvenile oysters, which are the food source of R. venosa. However, the regulatory mechanism of this induction is largely unknown. In the present study, we evaluated the impacts of induction by juvenile oysters on competent larvae of R. venosa. Competent larvae were experimentally divided into two pools, and scallop shells without juvenile oysters and scallop shells with juvenile oysters were added for 2 h and 12 h to monitor alterations in critical gene expression, symbiotic microbiota and metabolomic responses. The carboxypeptidase gene was increased while the cellulase gene was decreased, which may mean that the food habit transition was induced by juvenile oysters. Meanwhile, critical genes in the neuroendocrine system were also significantly altered in juvenile oysters. Furthermore, dramatic changes in the symbiotic microbiota and metabolism profiles were observed, with many of them associated with the digestive system and neuroendocrine system. In conclusion, juveniles as food resources may induce metamorphosis in R. venosa by regulating the neuroendocrine system and promoting the development of the digestive system and changes in digestive enzymes. This study may provide evidence that induction by juvenile oysters can promote food habit transition and metamorphosis in R. venosa by regulating the metabolome and microbiome and further altering the digestive and neuroendocrine systems of R. venosa, which expands our understanding of the regulatory mechanism of metamorphosis in R. venosa. However, further studies are needed to explore the specific substance inducing metamorphosis released by juvenile oysters.

Post-prandial changes in digestive enzymes and chyme characteristics of bigfin reef squid (Sepioteuthis lessoniana)

Bigfin reef squid (Sepioteuthis lessoniana) is a candidate squid species that has potential to be utilized in aquaculture on a commercial scale. Although this species has been successfully cultured over multiple generations, appropriate feeding strategies are still limited due to a lack of understanding of its digestive physiology. The present study focused on digestive enzymes and chyme characteristics in terms of time response profiles following feeding. Squids (1.78 ± 0.05 g body weight) were serially collected at different post-prandial times (0, 0.5, 1, 2, 4, 6, 8, 12, 18 and 24 h) and the specimens were used in the analysis of digestive enzymes (n = 10) and chyme characteristics (n = 5). Food provided to the animals substantially transited to the gastrointestinal tract and peaked at 1 h after feeding, and then dramatically decreased with post-prandial time (P < 0.05). The digestion process was initiated shortly after the food arrived and exhibited the same pattern over 24 h of observation. The highest activities of protein-, carbohydrate- and lipid-digesting enzymes were observed within a range of 0.5 to 4 h after feeding and reached basal levels as observed in fasted squids post-prandially within 8 h. Pearson correlation analysis indicated a highly significant relationship between digestive enzyme activity and digestosomatic index across post-prandial times (r = 0.660–1.000, P < 0.01). These responses matched well with chyme characteristics, in terms of thermal properties of nutrients, microstructure, and molecular weight patterns of the relevant proteins. Findings from the current study have thus provided basic information on the digestive physiology of bigfin reef squids that can be applied when designing specimen-harvesting strategies.

Cloning, expression and characterization of arcelin and its impact on digestive enzymes of the stored product insect pest, Callosobruchus maculatus (F.)

The pulse beetle Callosobruchus maculatus causes potential damage to legume crops by infesting the seeds, leading to a reduction of total protein content. Arcelin found in the wild accessions of the common bean, is an insecticidal protein that has the potency to hamper the metabolism of the bruchid beetle. The arcelin gene from the wild accession of Phaseolus lunatus was isolated and the ORF encoding 158 amino acids was cloned in pET-45b (+) vector. The recombinant clones were transformed in BL21 STAR (DE3) pLysS cells, and the expressed arcelin was purified using Ni-NTA column. The recombinant protein was used in preparing an artificial diet, and the insecticidal activity was elucidated against the bruchid pest C. maculatus. Adult emergence and seed damage were drastically reduced in the treated groups. The response towards ingested diet by digestive enzymes involved in metabolism was elucidated through quantitative gene expression. The highest expression was observed in the aminopeptidase, followed by upregulation of alpha-amylase, glycoside hydrolase family 31 and cathepsin D-like aspartic protease, and downregulation of cathepsin L-like cysteine protease. The recombinant arcelin demonstrates effective insecticidal activity against the bruchid beetle. The changes in digestive enzymes to counteract the anti-nutritional nature of the protein were the strategies of the insect defense mechanism.

Formation of Protein Corona on Nanoparticles with Digestive Enzymes in Simulated Gastrointestinal Fluids.

The protein corona (PC), which defines the biological identity of nanoparticles in the blood, is well-known, but no comprehensive and systematic study has been conducted yet on the formation of PCs in the gastrointestinal environment. Thus, this study aimed to explore the interaction between model polystyrene nanoparticles (PS-NPs) of 50-100 nm and three digestive enzymes, namely, pepsin, α-amylase, and trypsin. Results showed that the thicknesses of the PCs formed by α-amylase and trypsin were 25-100 and 50-100 nm, respectively. The zeta-potential values of PS-NPs after incubation significantly increased. The fluorescence quenching and ultraviolet-visible-absorption spectra suggested that interactions between the nanoparticles and the enzymes occurred. Synchronous fluorescence spectra showed that the PS-NPs could induce microenvironmental changes in digestive enzymes. The thermodynamic parameters suggested that the interaction was mainly driven by hydrogen bonds and van der Waals forces.

Seasonal changes in digestive enzymes in five bird species

Most animals must cope with seasonal fluctuations in environmental conditions, including variations in food availability and composition. Accordingly, it is expected that most species should exhibit reversible seasonal phenotypic adjustments in their physiology. Here, we assessed seasonal variation in the activity of three digestive enzymes (sucrase, maltase, and aminopeptidase-N) in one omniviorous bird species (Rufous-collared Sparrow (Zonotrichia capensis (P. L. Statius Müller, 1776))), three granivorous bird species (Black-chinned Siskin (Carduelis barbata (Molina, 1782)), Common Diuca Finch (Diuca diuca (Molina, 1782)), and Mourning Sierra Finch (Phrygilus fruticeti (Kittlitz, 1833))), and one insectivorous bird species (Plain-mantled Tit-Spinetail (Leptasthenura aegithaloides (Kittlitz, 1830))). Based on the adaptive modulation hypothesis, we predicted that the omnivorous species should exhibit the largest seasonal variation in the activity of its digestive enzymes in relation to granivorous and insectivorous species. We found that Z. capensis adjusts total activities of disaccharidases, total sucrase activity varied between seasons in C. barbata, and total activity of aminopeptidase-N only changed seasonally in L. aegithaloides. Moreover, this last species modified the tissue-specific activity of both disaccharidases as well as the wet mass of its intestine. Taken together, our results suggest that seasonal dietary changes occur in most of the species, regardless of the trophic categories in which they belong. Consequently, a better knowledge of the diet and its seasonal variation is necessary to better account for the results recorded in this study.

Changes in digestive enzymes through developmental and molt stages in the spiny lobster, Panulirus argus

Changes in major digestive enzymes through developmental and molt stages were studied for the spiny lobster Panulirus argus. There were significant positive relationships between specific activity of trypsin and amylase enzymes and lobster size, whereas esterase and lipase specific activities decreased as lobsters aged. No relationship was found between amylase/trypsin ratio and lobster size. Positive trends were found, however, for trypsin/lipase and amylase/lipase ratios. Results suggest that changes in enzyme activity respond to the lobsters' physiological needs for particular dietary components although multivariate analysis suggested that enzyme activities could be not totally independent of diet. On the other hand, the pattern of changes of major enzyme activities through molt cycle was similar for most enzymes studied. Following molt, trypsin, chymotrypsin, amylase, and lipase activities gradually increased to maximal levels at late intermolt (C 4) and premolt (D). There were no variations in the electrophoretic pattern of digestive enzymes through developmental and molt stages and thus, it is demonstrated that regulation is exerted quantitatively rather than qualitatively. Further studies on the effect of other intrinsic and extrinsic factors on digestive enzyme activities are needed to fully understand digestive abilities and regulation mechanisms in spiny lobsters.

The changes in digestive enzymes and hormones of gilthead seabream larvae (Sparus aurata, L 1758) fed on Artemia nauplii enriched with free methionine

Variations in digestive enzymes and hormones during the larval development of gilthead seabream (Sparus aurata) fed on live prey (Artemia nauplii) enriched with free methionine were investigated for 16 days (from day 24 to day 40). Prior to initiation of the experiment, newly hatched larvae were transferred from incubators to fiber glass tanks (300 l) with black walls and fed with same diets until day 24. Each experiment was performed in triplicate. In the experimental group, the content of the free methionine in the Artemia nauplii was increased by adding a 5.3 mM free methionine solution to the culture water during a 16-h enrichment period. The larvae of both the control and enriched-methionine groups were sampled four times, with 4-day intervals between samplings, during a 16-day period. The larvae in the control group had a significantly lower growth than those of the methionine group at the end of the study (P 0.05), but they were significant at 15th minute post-initiation of feeding (P < 0.05). A significant difference between the cholecystokinin levels of the treatment groups was found (P < 0.05).

Reduced lipid intake leads to changes in digestive enzymes in the intestine but has minor effects on key enzymes of hepatic intermediary metabolism in rainbow trout (Oncorhynchus mykiss)

For sustainable aquaculture, the removal of marine resource ingredients in fish diets is an important objective. While most studies focus on the replacement of fish oil by vegetable oil, little is known on the nutritional effects of presence (which corresponds to the control diet) or absence of dietary fish oil. We studied fatty acid composition of brush-border membranes and digestive enzyme activities of the intestine and measured the expression and activities of several enzymes involved in the hepatic intermediary metabolism of rainbow trout (Oncorhynchus mykiss) fed for 7 weeks with or without fish oil. The diets were pair-fed to ensure that fish fed either diet had comparable carbohydrate and protein intakes. Absence of fish oil significantly reduced growth rate, protein efficiency and plasma lipid components. Activities of intestinal digestive enzymes were significantly decreased in the anterior intestine in fish fed without fish oil. In liver, dietary fish oil removal did not affect the transcript levels or activities of the main enzymes involved in lipogenesis (fatty acid synthase) and fatty acid β-oxidation (3-hydroxyacyl-CoA dehydrogenase), glycolysis or amino acid oxidation. It lowered the expression of the genes coding for gluconeogenic enzymes (glucose-6-phosphatase and phosphoenolpyruvate carboxykinase), but their enzyme activities were not affected. The activities, but not gene expression of lipogenic enzymes, involved in NADPH and malonyl-CoA formation were also modified after fish oil removal as reflected by higher activities of isocitrate dehydrogenase/glucose-6-phosphate dehydrogenase and acetyl-CoA carboxylase enzymes. Overall, our results indicate that the intestinal digestive capacity was strongly modified by dietary fish oil removal, while hepatic intermediary metabolism was only marginally affected, in fed rainbow trout.

Functional changes in digestive enzymes and characterization of proteases of silver carp (♂) and bighead carp (♀) hybrid, during early ontogeny

Study of digestive enzyme and partial characterization of proteases of silver carp (♂) and bighead carp (♀) hybrid during early ontogeny was performed. Specific amylase activity was observed in 4 DAH (0.07 ± 0.01 mg maltose mg protein − 1 min − 1 ) carp hybrid. Specific amylase activity showed polynomial relationship with the age of fish. Total protease, trypsin and chymotrypsin activities were 14.37 ± 2.21, 11.38 ± 1.67 and 2.83 ± 0.50 mUnits mg protein − 1 min − 1 in 4 DAH fish, respectively. Total protease activity showed exponential trend, whereas trypsin and chymotrypsin activities showed polynomial relationships with the increasing age of the fish. Lipase activity was 2.33 ± 0.18 mUnits in 4 DAH carp hybrid. Lipase activity showed polynomial trend with the increasing age of fish. In inhibition study, SBTI, PMSF, TLCK and TPCK inhibited the protease activity by 83.0% to 92.0%, 71.0% to 81.0%, 45.1% to 55.5% and 35.8% to 48.2%, respectively. SDS-PAGE showed the presence of various protein bands (20.9–69.4 kDa) in carp hybrid during ontogenic development. Substrate SDS-PAGE revealed the presence of several protease activity bands (19.1–73.7 kDa) in digestive tissue extract of fish during ontogenesis. Inhibition of protease activity bands in substrate SDS-PAGE with SBTI and PMSF revealed the abundance of serine proteases and inhibition of activity bands with TLCK and TPCK evidenced the presence of more than one isoform of trypsin and chymotrypsin in the digestive tissue extract of hybrid carp.

Ontogenetic changes in digestive proteases and carbohydrases from the Australian freshwater crayfish, redclaw Cherax quadricarinatus (Crustacea, Decapoda, Parastacidae)

Juvenile redclaw crayfish, Cherax quadricarinatus, show non-selective feeding behaviour when commencing feeding, but change to a dietary preference for plant material as they grow. This study aimed to find any ontogenic changes in digestive enzymes that might be associated with the change of diet. The enzymes in the digestive tract initially showed high levels of proteases and low levels of carbohydrases, but as the crayfish grew, the levels of proteases fell and the levels of the carbohydrases generally rose, in parallel with the increased preference for plant food. Cellulase was present in all free-living stages. Dietary requirements of juvenile redclaw are probably quite similar to those of larger specimens.

Changes in sucrase, enterokinase, and peptide hydrolase after intestinal resection. The association of cellular hyperplasia and adaptation.

In a study of changes in digestive enzymes after massive intestinal resection and the mechanisms by which such changes occur, rats were sacrified 4 wk after removal of the proximal two-thirds of the small intestine. Alterations in the mucosal levels of sucrase, enterokinase, and dipeptide hydrolase (L-leucyl-L-alanine substrate) were examined in the light of associated changes in protein. DNA and wet mucosal weight, measured in standardized gut segments from various regions of intestine. Metabolic studies showed that normal growth patterns were reestablished after the operation but significant elevations in stool weight and fecal nitrogen occurred in the second postoperative week, falling towards normal by the 4th wk. In standard gut segments wet weight of mucosa, protein, and DNA rose, especially in distal segments, DNA increasing disproportionately. Mucosal levels of the proximally distributed and membrane-bound enzymes, sucrase and enterokinase, showed similar patterns of change: when enzyme activity was expressed in terms of the total per segment, proximally there were considerable increases in both enzymes, but, expressed in terms of specific activity, that of sucrase fell and that of enterokinase was unaltered. By contrast, the largely soluble and more distally distributed dipeptide hydrolase increased more in distal segments and the increases in total activity were accompanied by lesser increases in specific activity. However, in spite of increases in total activity, enzyme activity per milligram DNA fell by over 50% in postanastomotic segments. Subcellular distribution studies showed no change in the percentage of the total activity which was membrane-bound and zymograms confirmed that no new dipeptide hydrolase had appeared after resection. It is concluded that increases in the segmental totals of various enzymes seen after resection are achieved by disproportinate increases in the number of mucosal cells per segment and that the greatest change in a particular enzyme occurs in the region where the enzyme is normally found in highest concentration.

Interpretation of inverse acclimation to temperature

In kidney of goldfish acclimated to 5, 15 and 25° C the peroxisomal enzyme peroxidase and the peroxisomal and cytoplasmic matrix enzyme catalase showed inverse (Precht type 5) acclimation. Peroxisomal D-amino acid oxidase and lysosomal acid phosphatase were unchanged in activity (Precht type 4). A review of literature data on enzyme acclimation patterns shows that generally enzymes concerned with energy liberation — enzymes of glycolysis, hexose monophosphate shunt, TCA cycle and electron transport, also Na, K-ATPase and the synthetic amino acyl transferase — show compensatory acclimation to temperature (Precht type 3). Enzymes for degradation of metabolic intermediates and products such as peroxisomal and lysosomal enzymes, Mg-ATPase, acetylcholine esterase, show no or inverse acclimation to temperature. Changes in digestive enzymes depend on state of nutrition.