Hemolymph Glucose Levels Research Articles

Palliative effect of abalone insulin-related peptide 2 on emersion stress-induced hyperglycemia in the Pacific abalone (Haliotis discus hannai)

The Pacific abalone (Haliotis discus hannai), an economically important marine mollusk in East Asia, is often exposed to extreme environments, such as high water temperatures during summer and air exposure during handling or transportation. These stressful conditions lead to hyperglycemia and the generation of reactive oxygen species (ROS), resulting in oxidative stress and subsequent cell damage in the organism. To understand the role of insulin-related peptides in the regulation of elevated hemolymph glucose, hyperglycemia was confirmed in abalone under high water temperature and air (emersion) exposure (p < 0.05). To prove the existence of a glucose regulatory system in abalone, changes in hemolymph glucose were measured after bovine insulin injection, and hemolymph glucose was lowered by bovine insulin injection in hyperglycemia caused by both stressors (p < 0.05), supporting the existence of a glucose regulatory system functionally similar to that of vertebrates. Among the three abalone insulin-related peptides (AIPs), which were previously reported to be upregulated along with hemolymph glucose levels upon feeding, the relative mRNA expression of AIP2 in the cerebral ganglion showed a close correlation with high water temperature and emersion stress, which peaked 12 h after treatment (p < 0.05). Based on these results, we focused on the function of AIP2 in glucose homeostasis and characterized the localization of AIP2 mRNA-expressing cells in the cerebral ganglion using in situ hybridization. Positive signals from RNA probes were detected in neural cortex cells in the cerebral ganglion. Furthermore, suppressing AIP2 mRNA expression using RNA interference with double-stranded RNA (dsRNA) revealed that dsRNA-AIP2 injected abalone maintained high hemolymph glucose levels after 24 h of recovery following 1 h of emersion stress (p < 0.01). In contrast, abalones that received dsRNA-GFP and molluscan saline showed relatively rapid clearance of hemolymph glucose. This study demonstrates that AIP2 gene expression affects the recovery rate from emersion stress-induced hyperglycemia by regulating hemolymph glucose.

The impact of Roundup® Original DI on the hemolymph metabolism and gill and hepatopancreas oxidative balance of Parastacus promatensis (Crustacea, Decapoda, Parastacidae).

In Brazil, glyphosate is present in more than 130 commercial formulations, and its toxic effects have already been tested in different species to understand its impact on biota Decapod crustaceans are widely used as experimental models due to their biology, sensitivity to pollutants, ease of collection, and maintenance under laboratory conditions. We evaluated the changes in metabolism (hemolymph) and oxidative balance markers (gill and hepatopancreas) of a crayfish (Parastacus promatensis) after exposure to Roundup® (active ingredient: glyphosate). The crayfish were captured in the Garapiá stream within the Center for Research and Conservation of Nature Pró-Mata, Brazil. We collected adult animals outside (fall) and during (spring) the breeding season. The animals were transported in buckets with cooled and aerated water from the collection site to the aquatic animal maintenance room at the university. After acclimatization, the animals were exposed to different concentrations of glyphosate (0, 65, 260, 520, and 780 µg/L). The results showed a significant variation in the hemolymph glucose, lactate, and protein levels. We observed variations in the tissue antioxidant enzymatic activity after exposure to glyphosate. Finally, the increase in oxidative damage required a high energy demand from the animals to maintain their fitness, which makes them more vulnerable to stress factors added to the habitat.

Metabolic and immune status of Pacific white shrimp Penaeus vannamei concerning farming conditions

Biomarkers for monitoring shrimp health have been proposed but scarcely evaluated at the farm level. We analyzed several indicators of energy status in shrimp under farming conditions concerning stocking densities (100 m-2 with biofloc, 15 and 7 m-2). The influence of the year's season (temperature) was also analyzed, and, finally, an unfortunate event of White spot syndrome virus (WSSV) infection occurred on the 7 m-2 farms, adding another condition. At shrimp sampling from ponds, the effect of acute handling stress was also analyzed for indicators typically affected by such procedure with a 3- and 10-fold increase in glucose and lactate levels in hemolymph, respectively, regardless of density. This response was partially blunted at lower temperatures and WSSV incidence. Increased levels of protein in the hepatopancreas, adenylic energy charge (AEC) in both hepatopancreas and muscle and phosphagens in muscle were observed in shrimp from the 100 m-2 farms, suggesting a better nutritional and energetic status in shrimp cultured at high density with biofloc technology. Shrimp with WSSV presented lower hemocyanin levels in hemolymph, most likely associated with its role in the immune response. In WSSV-infected shrimp, the stress response regarding glucose increase was blunted, whereas a stress-induced increase in triglycerides (TG) levels in hemolymph was observed only with WSSV. Increased TG levels in those shrimp hepatopancreas could indicate a switch from carbohydrate to lipid-based metabolism associated with the preferential use of carbohydrates (Warburg effect) for virus replication in the early infection state.

Dietary protein-to-carbohydrate ratio effects development and metabolism in Drosophila larvae and imago

Background. Nutrition during growth and development affects various traits not only in larvae but also imago including lifespan, reproduction, feeding, metabolism, and stress resistance. In this study, we have tested the hypothesis of whether the dietary protein-to-carbohydrate (P:C) ratio in the developmental diet could be related to subsequent changes in metabolic profile and physiological parameters in Drosophila larvae and imago. Materials and Methods. Drosophila melanogaster Canton-S strain were used in this study. Larvae were fed diets with different P:C ratios. Experimental media were composed of either 2 % or 5 % dry yeast and 0 %, 1 %, or 10 % of sucrose. We tested developmental rate, wet or dry body weight and the levels of certain metabolites inclu­ding glucose, glycogen, triacylglycerides and total lipids. The developmental rate was assessed by counting the number of generated pupae every 6/6/12 hours. For wet or dry weight measurement, 20 larvae or flies were weighed and transferred to plastic vial with a cut bottom. The flies were dried at 60 °C with the subsequent weighing after two days. Another two-day flies cohort were separated by sex and frozen in liquid nitrogen for further biochemical assays. Hemolymph glucose, total lipid concentration, triacyl­glycerides (TAG), body glucose and glycogen contents were determined spectrophotometrically. Results. We found that a low 0.08 P:C ratio in the diet slowed down pupation by ~20 % and decreased body weight in larvae. Hemolymph glucose levels in both larvae and imago were inversely associated with dietary P:C. Larvae developing on a diet with a low P:C ratio displayed a lower level of glycogen pool, but a higher level of lipids. Developmental dietary P:C ratio also influences metabolic traits such as hemolymph glucose, glycogen, TAG and total lipids in male and female imago. A higher total protein intake combined with restriction of sucrose consumption had glucose-lowering and lipids-lowering effects. Conclusions. Our study demonstrated that nutritional conditions during larval development trigger adaptive changes that provide a level of regulation necessary to surpass dietary stress in Drosophila imago.

Implications of dietary phosphorus sources on zootechnical performance and stress response of the pacific white shrimp Litopenaeus vannamei

The phosphorous (P) is an essential element for several functions, including the synthesis of high energy compounds in cells like adenosine triphosphate (ATP) and arginine phosphate (ArgP). The dietary requirements of P could change according to physiological and environmental conditions, particularly if organisms are exposed to stress conditions. As the P availability could be related to its chemical form in the diet, the present study analyzed the influence of different P sources (KH2PO4, NaH2PO4, NH4H2PO4, Na5P3O10), on the stress response of the Pacific white shrimp Litopenaeus vannamei. Final weight was 8.5% higher (p < 0.01) in shrimp fed on tripolyphosphate (Na5P3O10) diet compared with the monophosphate diets. Weight gain and specific growth also trend to increase, whereas feed conversion ratio trend to decrease with this polyphosphate source, although not significantly. Stress response of shrimp exposed to handling followed by hypoxia was characterized by an overall increase of lactate and glucose levels in hemolymph, as well as a decrease in Adenylate Energy Charge (AEC) and ArgP in the muscle. No effect of dietary P sources was observed on baseline biochemical composition and overall indicators of stress response, except for higher carbohydrate levels in hepatopancreas and RNAm expression of arginine kinase (AK) in muscle with the NaH2PO4 diet, suggesting a potentially better energy status with this diet.

Adaptation of Glucose Metabolism to Limb Autotomy and Regeneration in the Chinese Mitten Crab.

Limb autotomy and regeneration represent distinctive responses of crustaceans to environmental stress. Glucose metabolism plays a pivotal role in energy generation for tissue development and regeneration across various species. However, the relationship between glucose metabolism and tissue regeneration in crustaceans remains elusive. Therefore, this study is aimed at analyzing the alterations of glucose metabolic profile during limb autotomy and regeneration in Eriocheir sinensis, while also evaluating the effects of carbohydrate supplementation on limb regeneration. The results demonstrated that limb autotomy triggered a metabolic profile adaption at the early stage of regeneration. Hemolymph glucose levels were elevated, and multiple glucose catabolic pathways were enhanced in the hepatopancreas. Additionally, glucose and ATP levels in the regenerative limb were upregulated, along with increased expression of glucose transporters. Furthermore, the gene expression and activity of enzymes involved in gluconeogenesis were repressed in the hepatopancreas. These findings indicate that limb regeneration triggers metabolic profile adaptations to meet the elevated energy requirements. Moreover, the study observed that supplementation with corn starch enhanced limb regeneration capacity by promoting wound healing and blastema growth. Interestingly, dietary carbohydrate addition influenced limb regeneration by stimulating gluconeogenesis rather than glycolysis in the regenerative limb. Thus, these results underscore the adaptation of glucose metabolism during limb autotomy and regeneration, highlighting its essential role in the limb regeneration process of E. sinensis.

Growth and Health Status of Spiny Lobsters and Snubnose Pompano with Multilevel Floating Net Cage System

The cultivation of multilevel floating net cages (MFNC) systems is believed to be able to increase production capacity without increasing the horizontal area of ​​the cultivation area. Research on the effect of using MFNC on the growth and health performance of Spiny lobsters and Snubnose pompano has never existed, so a study was conducted with the aim of comparing the growth and health performance of spiny lobsters and Snubnose pompano in floating net cage (FNC) and MFNC cultivation systems. The research method used was a field experiment with a comparative analysis of spiny lobsters and Snubnose pompano cultivation with different cultivation systems, namely the MFNC and FNC systems with 3 replications. The rearing lasted for 2 months and was fed trash fish as much as 5% of the biomass every day. Parameters of spiny lobsters and Snubnose pompano growth performance observed included weight growth, carapace length growth, total length growth, and specific growth rate. The health status of spiny lobsters observed quantitatively was the total hemocytes counts and hemolymph glucose levels, and Snubnose pompano by counting erythrocytes and blood leukocytes. The results showed that there was no difference in growth performance, survival and health status of spiny lobsters and Snubnose pompano reared using MFNC and FNC systems based on paired two sample for means, because p value &gt; 0.05 for all growth parameters survival and health status. Thus, the use of a multilevel floating net cage system in lobster cultivation can increase FNC productivity and be efficient in optimal space utilization and does not affect water quality, especially the parameters of temperature, pH, dissolved oxygen and salinity. There were no significant differences in the growth performance, survival, and health status of lobsters and Snubnose pompano when reared using the MFNC and FNC cultivation systems.

Tyramine mediates growth performance, immune response, and physiological regulation of Litopenaeus vannamei through dietary administration

In this study, the effects of feeding diets containing tyramine (TA) to Litopenaeus vannamei at levels of 10 (TA10), 50 (TA50), and 100 (TA100) mg/kg on growth performance, immune parameters, hemolymph glucose and lactate level, biogenic amine synthesis, and resistance against Vibrio alginolyticus were investigated. Results showed that shrimp fed with TA-containing diets had significantly higher feed efficiency and percent weight gain for a period of 56 days. The total hemocyte count increased in TA10, TA50 and TA100 after 7 and 28 days, and increased in TA100 after 14 days. The phenoloxidase activity increased in TA100 after 7 days, and respiratory bursts increased in TA100 after 7 and 14 days. In terms of resistance against V. aliginolyticus infection, the phagocytic activity increased in TA10, TA50 and TA100 after 7–28 days. The clearance efficiency increased in TA10, TA50 and TA100 after 7 and 14 days, and increased in TA 100 after 28 days. Shrimp fed with TA50 and TA100 for 28 days then challenged with V. aliginolyticus had a higher survival rate compared to those fed the basal diet at 48 h–168 h post challenges. The hemolymph glucose level was significantly decreased after being fed with TA10 at 28 days and TA100 for 56 days, while the octopamine synthesis in shrimp was improved after 14 days of being fed with TA50 and TA100, and after 28 days of being fed with TA100. These findings suggest that administering a TA diet regulated the growth performance, immune response and V. aliginolyticus resistance in L. vannamei.

Mechanism of hyperproteinemia-induced damage to female reproduction in a genetic silkworm model

Hyperproteinemia is a metabolic disorder characterized by abnormally elevated plasma protein concentrations (PPC) in humans and animals. Here, a genetic silkworm model with high PPC was employed to investigate the effect of elevated PPC on female reproduction. Transcriptomic analysis revealed that high PPC induces downregulation of the ovarian development-related genes and disrupts ovarian sugar metabolism. Biochemical and endocrinal analyses revealed that high PPC increases trehalose and glucose levels in hemolymph and glycogen content in the fat body through activation of the gluconeogenic pathway and inhibition of the Insulin/Insulin-like growth factor signaling pathway-the serine/threonine kinase (IIS-AKT) pathway, thus disrupting characteristic metabolic homeostasis of sugar in the ovary. These resulted in ovarian developmental delay as well as reduced number and poor quality of eggs. Insulin supplementation effectively increased egg numbers by lowering blood sugar. These collective results provide new insights into the mechanisms by which high PPC negatively affects female reproduction and support the potential therapeutic effects of insulin.

A mitotoxic fungicide alters post-ingestive glucose signals necessary for associative learning in honey bees

The Proboscis Extension Reflex (PER) paradigm trains honey bees to associate an odor with a sugar reward and is commonly used to assess impacts on associative learning after exposure to pesticides. While the effects of some types of pesticides have been well-investigated, relatively little attention has been focused on fungicides that are applied to flowering crops. We have previously shown that consumption of field-relevant concentrations of the fungicide Pristine® (active ingredients: 25.2% boscalid, 12.8% pyraclostrobin) impairs honey bee performance in an associative learning assay, but the mechanism of its action has not been investigated. We hypothesized that Pristine® interferes with carbohydrate absorption and/or regulation, thereby disrupting the post-ingestive feedback mechanisms necessary for robust learning. To test this hypothesis, we measured hemolymph glucose and trehalose levels at five time points during the ten minutes after bees consumed a sucrose solution. Pristine®-exposed bees had elevated baseline glucose concentrations in the hemolymph relative to control bees. Hemolymph glucose levels rose significantly within five minutes of feeding in control bees, but not in Pristine®-fed bees. These data suggest that the post-ingestive feedback mechanisms necessary for robust learning are disrupted in bees that have consumed this fungicide, providing a plausible mechanistic explanation for its effects on learning performance in the PER assay. Pristine®-exposed bees may have elevated hemolymph glucose levels because the fungicide elicits an inflammatory response. These results provide additional mechanistic understanding of the negative physiological effects of mitotoxic fungicides on this important pollinator.

Assessment of metabolic flexibility by RER in the Gromphadorhina portentosa

Metabolism is the series of chemical reactions utilized by organisms to create energy to drive physiological and cellular functions. Understanding the metabolism of ectothermic organisms has been an area of interest that is widely understudied with limited model organisms. Using the Gromphadorhina portentosa (Giant Madagascar Hissing Cockroach) as a model organism, ectothermic metabolism was measured by respirometry using a closed animal chamber and iWorx gas analyzer. The metabolic rate was calculated as the Respiratory Exchange Ratio (RER), which is the ratio of carbon dioxide produced to oxygen consumed. We investigated whether changes in metabolism were allometric functions dependent on the size of cockroaches. Experiments were conducted to study the effects of high temperatures, exercise and diet on the metabolic rate of G. portentosa compared to control. Preliminary data showed significant changes in RER under several of these experimental conditions. We have also investigated whether the environmental conditions produced sex- and age-specific changes in RER. Lastly, we utilized biochemical assays to determine why several experimental groups exhibit RERs &gt;1.0. Preliminary results show glucose and triglyceride levels in hemolymph accommodate metabolic flexibility requirements in the above experimental conditions. This work represents the most comprehensive evaluation of this ectotherm and adds to our understanding of one of the largest insects. APU This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

STARVATION DURING DEVELOPMENT AFFECTS METABOLISM IN DROSOPHILA

Aim. To investigate how starvation during early stage of fly development affects carbohydrate metabolism in imago flies and their progeny of F1 generation. Methods. Wild-type Canton-S strain Drosophila melanogaster flies were used in all experiments. Flies of parental and offspring generations were used for the determination of glycogen and glucose content using the diagnostic kit Glucose-Mono-400-P according to the manufacturer's instructions. Results represent as the mean ± SEM of 3-4 replicates per group. According Student's t-test significant difference between groups was P&lt;0.05. Graphing and statistical analysis were performed by using GraphPad Prism. Results. Starvation during development significantly influenced the level of hemolymph and body glucose in imago flies of parental generation. Hemolymph glucose concentration was lower by 34% (P=0.008) and 32% (P=0.033) in experimental females and males, respectively, as compared to control groups. Starvation during development led to lower level of body glucose in adult parental flies of both sexes. Adult males F1, generated by parents that were starved during development, showed 3-fold lower glycogen content, as compared to control. Conclusions. Starvation at early stage of development led to lower hemolymph glucose and body glucose level in imago flies. Moreover, parental starvation decreased glycogen pool in F1 males.

Molecular identification of an insulin-like peptide from the swimming crab Portunus trituberculatus and evidence for its glucoregulation function

Insulin-like peptides (ILPs) are essential to the animal kingdom for regulating growth and development, reproduction, behavior, metabolism, and lifespan. In crustaceans, the most well-known ILP is insulin-like androgenic gland hormone, a key hormone in regulating sex differentiation and reproduction. Identification of other ILPs and their functions are still limited. In this study, an insulin-like peptide gene of the swimming crab Portunus trituberculatus was cloned and characterized. Its transcripts were mainly found in nerve tissues and expression could be induced by glucose, implying a putative role in glucoregulation. After depletion of endogenous ILP, injection of ILP dsRNA (dsILP) significantly elevated blood glucose levels and recombinant ILP (rILP) decreased hemolymph glucose levels, further clarifying the involvement of acquired ILP in hemolymph glucose regulation. Injection of dsILP decreased PtAkt, PtGS, PtPFK and increased PtGSK and PtPEPCK gene expression. The opposite profile was observed after glucose and rILP injection, indicating that PtILP might negatively regulate hemolymph glucose levels via the IIS (insulin/IGF-1 signaling) pathway by inhibiting gluconeogenesis and promoting glycogen synthesis and glycolysis. This study has refined the mechanism of glucose regulation in crustaceans and laid the foundation for further studies on ILP function.

Nutritional geometry framework of sleep

AimsSleep is a fundamental physiological function and is essential for all animals. Sleep is affected by diet compositions including protein (P) and carbohydrates (C), but there has not been a systematic investigation on the effect of dietary macronutrient balance on sleep. Main methodsWe used the nutritional geometry framework (NGF) to explore the interactive effects on sleep of protein (P) and carbohydrates (C) in the model organism Drosophila. Both female and male flies were fed various diets containing seven ratios of protein-to-carbohydrates at different energetic levels for 5 days and sleep was monitored by the Drosophila Activity Monitor (DAM) system. Key findingsOur results showed that the combination of low protein and high carbohydrates (LPHC) prolonged sleep time and sleep quality, with fewer sleep episodes and longer sleep duration. We further found that the effects of macronutrients on sleep mirrored levels of hemolymph glucose and whole-body glycogen. Moreover, transcriptomic analyses revealed that a high-protein, low-carbohydrate (HPLC) diet significantly elevated the gene expression of metabolic pathways when compared to the LPHC diet, with the glycine, serine, and threonine metabolism pathway being most strongly elevated. Further studies confirmed that the contents of glycine, serine, and threonine affected sleep. SignificanceOur results demonstrate that sleep is affected by the dietary balance of protein and carbohydrates possibly mediated by the change in glucose, glycogen, glycine, serine, and threonine.

20-Hydroxyecdysone and Receptor Interplay in the Regulation of Hemolymph Glucose Level in Honeybee (Apis mellifera) Larvae.

The hormone 20-hydroxyecdysone (20E) and the ecdysone receptors (ECR and USP) play critical roles in the growth and metabolism of insects, including honeybees. In this study, we investigated the effect of 20E on the growth and development of honeybee larvae by rearing them in vitro and found reduced food consumption and small-sized pupae with increasing levels of 20E. A liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based analysis of widely targeted metabolomics was used to examine the changes in the metabolites after an exogenous 20E application to honeybee larvae and the underlying mechanisms. A total of 374 different metabolites were detected between the control group and the 20E treatment group, covering 12 subclasses. The most significant changes occurred in 7-day-old larvae, where some monosaccharides, such as D-Glucose and UDP-galactose, were significantly upregulated. In addition, some metabolic pathways, such as glycolysis/gluconeogenesis and galactose metabolism, were affected by the 20E treatment, suggesting that the 20E treatment disrupts the metabolic homeostasis of honeybee larvae hemolymph and that the response of honeybee larvae to the 20E treatment is dynamic and contains many complex pathways. Many genes involved in carbohydrate metabolism, including genes of the glycolysis and glycogen synthesis pathways, were downregulated during molting and pupation after the 20E treatment. In contrast, the expression levels of the genes related to gluconeogenesis and glycogenolysis were significantly increased, which directly or indirectly upregulated glucose levels in the hemolymph, whereas RNA interference with the 20E receptor EcR-USP had an opposite effect to that of the 20E treatment. Taken together, 20E plays a critical role in the changes in carbohydrate metabolism during metamorphosis.

Amelioration of ammonia-induced intestinal oxidative stress by dietary Clostridium butyricum in giant freshwater prawn (Macrobrachium rosenbergii)

The use of Clostridium butyricum in crustacean aquaculture for anti-abiotic stress is yet unknown. Feeds were formulated containing 0, 125, 250, 500, and 1000 mg/kg Clostridium butyricum (2 × 107 CFU/g), respectively. The giant freshwater prawns (Macrobrachium rosenbergii) were fed for 8 weeks in triplicate. The results showed that C. butyricum-supplemented groups improved growth performance significantly with the optimum level at 610 mg/kg. Ammonia stress reduced hemolymph glucose, total protein, total cholesterol, and triglyceride concentrations while dietary C. butyricum significantly increased hemolymph glucose and total protein levels after the ammonia challenge. Ammonia stress increased inducible nitric oxide synthase (iNOS) and nitric oxide (NO) levels, and the treatments supplemented with C. butyricum had considerably enhanced levels of iNOS and NO after stress. Treatment with C. butyricum increased the level of superoxide dismutase (SOD), and decreased the level of malondialdehyde (MDA) and superoxide anion, with the 125 mg/kg treated groups having the extreme value. Furthermore, C. butyricum-treated groups reduced the expression of HSPs after ammonia stress while the ammonia stress induced the expression of HSP60, HSP70, and HSP90. Dietary C. butyricum elevated the expression of peroxiredoxin-5 and toll in response to ammonia stress. The results indicate that dietary supplementation with 125–500 mg/kg of C. butyricum (2 × 107 CFU/g) improved biochemical and antioxidant features as well as intestinal immunity of M. rosenbergii under ammonia challenge by activating the toll signal pathway.

A comparative study of natural variation in hemolymph glucose levels under different dietary sugar conditions in Drosophila melanogaster and D. simulans.

Physiological responses to environmental changes play important roles in adaptive evolution. In particular, homeostatic regulatory systems that maintain constant circulating glucose levels are crucial in animals. However, variation in circulating glucose levels and the genetic effects on phenotypic variation in natural populations remain to be clarified. Here, we investigated the hemolymph glucose levels in natural populations of Drosophila melanogaster and its sibling species, D. simulans, in Japan. We quantified hemolymph glucose concentrations in third instar larvae of 27 lines for each species, which were reared on either glucose-free or glucose-rich food. In both species, genetic variation was not a major component of phenotypic variation on either glucose-free or glucose-rich food. The hemolymph glucose concentrations were much higher in D. simulans than in D. melanogaster. Genetic variance was larger in D. simulans than in D. melanogaster. The observed differences between the two species may be associated with the much more recent colonization history of D. simulans populations in Japan and/or the tolerance to environmental stresses. Our findings suggest that natural selection acting on hemolymph glucose levels in D. melanogaster is different from that in D. simulans.

Probiotic (protexin) modulates glucose level in sucrose-induced hyperglycaemia in Harwich strain Drosophila melanogaster

BackgroundProbiotics are beneficial microorganisms that alter microbial flora to promote human and animal health by ameliorating the physiological and psychological hitches and distress. The aim of the study was to investigate the protective effect of probiotic (protexin) in sucrose induced hyperglycaemia in Harwich strain Drosophila melanogaster.MethodsFor lethal concentration, different concentrations of probiotic were fed on fresh breaded D. melanogaster for two weeks in two phases. The concentrations varied from 10 to 1000 mg. For increment in haemolymph glucose level, Insta-larva of 540 D melanogaster was divided into six groups of thirty larva (n = 30) each in triplicate. Baseline glucose level was determined by administering group normal diet, while group 2–6 were fed with a normal diet containing 30% sucrose. For body weight, Eppendorf microtubes were weighed and anaesthetised flies were transferred into the tubes which were, re-weigh to get the actual weight of the flies before and after sucrose intake. Treatment supplement was introduced after flies emerged to be three days old. Group I: (Normal Control) received a normal cornmeal diet 30 g. Group II: (positive control) received normal diet + 30% sucrose only. Group III; received 10 mg of metformin/30 g diet. Group IV received 250 mg of probiotic/30 g of normal diet. Group V received 500 mg of probiotic/30 g normal diet. Group VI received 1000 mg of probiotic/30 g normal diet. All treatments lasted for 7 days. At the end of the treatment period, flies were immobilized and anaesthetised in ice and homogenised vigorously in 0.1 M phosphate buffer, pH 7.4. Eppendorf microtubes were weighed and anesthetized flies were transferred into them, and re-weighed with appropriate micro-litre of phosphate buffered saline (PBS) added and the flies were squashed to get the supernatant. The resulting homogenates were centrifuged at 10,000×g, 4 °C for 10 min. The supernatant was separated from the pellets into labelled tubes and used for the various biochemical assays. Data were expressed as mean ± standard error of mean (SEM) and subjected one-way analysis of variance (ANOVA), followed by Tukey post-hoc test for multiple comparisons between groups. Statistical package Graph Pad Prism version 8.1 was used for statistical analysis and values of p ˂ 0.05 were considered significant. Lethal concentration, logic probit test software was used.ResultsThe dosage of probiotic ranging from 10 to 1000 mg were not toxic to the fruit-fly. The LC50 of protexin after seven days was found to be greater than 1000 mg. Significantly (p < 0.05) decreased in hemolymph glucose concentration was recorded for the base-line (phase one) in the normal control group, compared to diabetic-induced groups. There was a significant (p < 0.05) decline in body weight and blood glucose level in all the treatment groups, when compared to the diabetic untreated group.ConclusionsAdministration of sucrose diet increased the blood glucose level and body weight in diabetic D. melanogaster flies, mitigated by administration of probiotics (protexins).

Marine protein hydrolysates as a substitute of squid‐liver powder in diets for Pacific white shrimp ( Litopenaeus vannamei )

This study was conducted to examine the supplementary effects of tuna hydrolysate (TH) and shrimp hydrolysate (SH) as squid-liver powder (SLP) replacers in a high soybean meal diet for Pacific white shrimp (Litopenaeus vannamei). A diet containing 4.49% SLP was regarded as the control diet and two other diets were prepared by supplementing 1.14% tuna hydrolysate (TH) and 0.94% shrimp hydrolysate (SH) (designated as SLP, TH and SH, respectively). Five replicate groups of shrimp (initial mean body weight, 0.35 ± 0.002 g) were fed one of the experimental diets for 52 days. Final body weight and weight gain of shrimp fed SH and TH diets were significantly higher than those of shrimp fed SLP diet (p < 0.05). Feed conversion ratio was lower in SH group compared to that of shrimp fed other diets. Total antioxidant capacity and catalase activity were significantly higher in TH or SH group than SLP group (p < 0.05). Hemolymph glucose and triglyceride levels of shrimp fed SLP were significantly lower than those of shrimp fed TH and SH (p < 0.05). Shrimp-fed TH or SH exhibited significantly higher carcass lipid composition than shrimp-fed SLP (p < 0.05). Dry matter and protein digestibility were significantly higher in SH diet (p < 0.05). The findings in this study indicate that SH and TH can be used as beneficial feed supplements or ingredients that could replace SLP in L. vannamei diet. Optimum inclusion level of SH would be approximately 1% to completely replace SLP in L. vannamei diet containing high level of soybean meal.

Effects of dietary carbohydrate-to-lipid ratios on growth performance, intestinal digestion, lipid and carbohydrate metabolism of red swamp crayfish (Procambarus clarkii)

Understanding the effects of dietary nutrients on physiological and biochemical parameters, especially the metabolism of nutrients during crayfish farming, can be useful for improving crayfish health and optimizing production in aquaculture. Therefore, we conducted an 8-week feeding study to investigate the effect of dietary carbohydrate-to-lipid (CHO: LIP) ratios on growth performance, hemolymph biochemical indices, intestinal digestion, hepatopancreas lipid, and carbohydrate metabolism of red swamp crayfish (Procambarus clarkii) (initial weight = 9.10 ± 0.15 g). Four isoenergetic and isonitrogenous diets (16.2 MJ kg−1 gross energy and 30.2% crude protein) were estimated to include different CHO:LIP ratios: 1.88 (22.5% CHO/11.9% LIP); 3.25 (29.3% CHO/9% LIP); 5.94 (36.2% CHO/6.1% LIP); and 13.60 (43.1% CHO/3.2% LIP). According to the results, the weight gain rate (WGR), final body weight, specific growth rate (SGR), intestinal amylase activity, abdominal muscle crude protein content, and protease activity significantly increased (P < 0.05) as the CHO:LIP ratio increased from 1.88 to 5.94 and then significantly decreased (P < 0.05) as the CHO:LIP ratio increased from 5.94 to 13.60. However, the feed conversion ratio exhibited the opposite trend. The abdominal muscle crude lipid content, hemolymph cholesterol content, and intestinal lipase activity significantly decreased with increasing dietary CHO:LIP ratios from 1.88 to 13.60, whereas the hemolymph glucose level showed the opposite trend. The activities of phosphofructokinase (PFK), the mRNA expression levels of pfk, pyruvate kinase (pk), lactate dehydrogenase (ldh), fatty acid synthase (fas), cholesterol regulatory element-binding protein 1 (srebp1), retinoic acid X receptor (rxr), and hexokinase (hk) in the hepatopancreas significantly increased with the increasing CHO:LIP ratios from 1.88 to 13.60, whereas the activities of lipoprotein lipase, hepatic esterase, and phosphoenolpyruvate carboxykinase, the mRNA expression levels of acyl coenzyme a oxidase (aco), fatty acid-binding protein gene (fabp), acyl-coA synthetase bubblegum (acsbg), glucose6-phosphatase (g6pase), pepck and fructose-1, 6-diphosphatase (fbpase) significantly decreased. The quadratic regression model showed that the optimal CHO: LIP ratio and dietary protein level for red swamp crayfish were 7.74% and 30%, respectively. These results suggest that optimal dietary CHO: LIP ratios could increase the SGR and WGR of red swamp crayfish. High CHO: LIP ratio inhibits gluconeogenesis and lipid degradation, while low CHO: LIP ratio inhibits glycolysis and lipogenesis.