Nutritional Compensation Research Articles

Endosymbiont Tremblaya phenacola influences the reproduction of cotton mealybugs by regulating the mechanistic target of rapamycin pathway.

The intricate evolutionary dynamics of endosymbiotic relationships result in unique characteristics among the genomes of symbionts, which profoundly influence host insect phenotypes. Here, we investigated an endosymbiotic system in Phenacoccus solenopsis, a notorious pest of the subfamily Phenacoccinae. The endosymbiont, "Candidatus Tremblaya phenacola" (T. phenacola PSOL), persisted throughout the complete life cycle of female hosts and was more active during oviposition, whereas there was a significant decline in abundance after pupation in males. Genome sequencing yielded an endosymbiont genome of 221.1kb in size, comprising seven contigs and originating from a chimeric arrangement between betaproteobacteria and gammaproteobacteria. A comprehensive analysis of amino acid metabolic pathways demonstrated complementarity between the host and endosymbiont metabolism. Elimination of T. phenacola PSOL through antibiotic treatment significantly decreased P. solenopsis fecundity. Weighted gene coexpression network analysis demonstrated a correlation between genes associated with essential amino acid synthesis and those associated with host meiosis and oocyte maturation. Moreover, altering endosymbiont abundance activated the host mechanistic target of rapamycin pathway, suggesting that changes in the amino acid abundance affected the host reproductive capabilities via this signal pathway. Taken together, these findings demonstrate a mechanism by which the endosymbiont T. phenacola PSOL contributed to high fecundity in P. solenopsis and provide new insights into nutritional compensation and coevolution of the endosymbiotic system.

Functional approach to D-fortification of sunflower oil as a factor of nutritional compensation of vitamin deficiency and immunoprophylaxis

In modern conditions of the spread of new strains of microorganisms, along with sanitary and hygienic issues of prevention, measures aimed at immunoprotection play an important role. Insufficient micronutrient supply of vitamin D contributes to a high susceptibility of a person to an infectious agent. Insufficient supply of vitamin D contributes to a high human susceptibility to an infectious agent. Adequate compensation for chronic deficiency of fat-soluble vitamin D in food belongs to a promising field of nutritionology. In the structure of oilseed production of Russian farmers, about 60% is occupied by sunflower oil, which practically lacks vitamin D. The development of fortified sunflower oil that compensates for this need solves a two-pronged task: as a preventive measure and as a biologically valuable food product. According to the research results, it has been established that the fortification of unrefined sunflower oil with the addition of 0.04... 0.20 ml of vitamin D3 oil solution with an activity of 50,000 M.E. provides coverage of 10-50% of the daily requirement for vitamin D3. In the samples of unpacked unrefined sunflower oil, the indicators of oxidative spoilage during storage up to 60 days corresponded to the normalized requirements for premium vegetable oil with lower indicators with an increase in the amount of vitamin D3 oil solution added.

Nutritional compensation of the circadian clock is a conserved process influenced by gene expression regulation and mRNA stability.

Compensation is a defining principle of a true circadian clock, where its approximately 24-hour period length is relatively unchanged across environmental conditions. Known compensation effectors directly regulate core clock factors to buffer the oscillator's period length from variables in the environment. Temperature Compensation mechanisms have been experimentally addressed across circadian model systems, but much less is known about the related process of Nutritional Compensation, where circadian period length is maintained across physiologically relevant nutrient levels. Using the filamentous fungus Neurospora crassa, we performed a genetic screen under glucose and amino acid starvation conditions to identify new regulators of Nutritional Compensation. Our screen uncovered 16 novel mutants, and together with 4 mutants characterized in prior work, a model emerges where Nutritional Compensation of the fungal clock is achieved at the levels of transcription, chromatin regulation, and mRNA stability. However, eukaryotic circadian Nutritional Compensation is completely unstudied outside of Neurospora. To test for conservation in cultured human cells, we selected top hits from our fungal genetic screen, performed siRNA knockdown experiments of the mammalian orthologs, and characterized the cell lines with respect to compensation. We find that the wild-type mammalian clock is also compensated across a large range of external glucose concentrations, as observed in Neurospora, and that knocking down the mammalian orthologs of the Neurospora compensation-associated genes CPSF6 or SETD2 in human cells also results in nutrient-dependent period length changes. We conclude that, like Temperature Compensation, Nutritional Compensation is a conserved circadian process in fungal and mammalian clocks and that it may share common molecular determinants.

Effect of incorporation of snail meat powder on sensory attributes and consumer acceptability of sorghum-wheat buns.

Formulation of foods from –low‐lysine cereals fortified with animal protein is a potentially sustainable approach to enhance protein quality in diet due to nutritional compensation while buns are valuable vehicles to deliver nutrients to human body because of their relatively noble eating quality and extended shelf life. The aim of this study was to evaluate the sensory attributes and consumer acceptability of sorghum‐wheat buns containing snail meat powder (SMP). Buns were prepared by replacing 5, 10, 15, 20, and 25% of sorghum‐wheat composite flour with SMP. Principal component analysis (PCA) revealed 99% total variation of 23 attributes for buns scored by a descriptive sensory panel, of which 98% was due to the proportion of SMP that replaced sorghum‐wheat composite flour in buns and the remainder 1% was due to the buns’ physical appearance. Compositing sorghum‐wheat buns with SMP imparted positive consumer attributes of fine crumb, sponginess, and crumby texture. It also resulted in buns with reasonably high sensory acceptability as evaluated by 8‐ to 9‐year‐old school children. The buns can serve as supplementary rich sources of protein for alleviating the menace of protein energy malnutrition in sub‐Saharan Africa.

Nutritional Characteristics of Rice (Oryza sativa L.) Composite Flours Obtained by Food Fortification

High prevalence of protein-energy malnutrition among the vulnerable population, especially children has prompted research on fortification of common staple cereal foods such as rice. However, rice has inferior nutritional value compared to other popular cereals, such as maize, therefore limiting its full utilization. Its storage protein, glutelins, is not easily digested by monogastric animals; therefore, food to food fortification of rice flours provides protein nutritional compensation as well as improvement of other nutrients. This study was carried out to determine the proximate and mineral (Fe, Zn, Mg, Ca, P) composition of rice composite flours. Methodology: The blending ratios (rice: maize: sorghum: pumpkin: carrots: baobab: amaranth) used in the study were 70:0:0:7.5:7.5:5:10 (AT1), 45.5:24.5:0:7.5:7.5:5:10 (AT2), 35:35:0:7.5:7.5:5:10 (AT3), 23.3:23.3:23.3:7.5:7.5:5:10 (AT4) and 100% rice flour (AT5). Proximate analyses were performed according to Association of Official Analytical Chemist (AOAC) methods. Atomic absorption spectroscopy was used to determine the minerals. Data analysis was done using Analysis of Variance (ANOVA). Mean comparisons for treatments were done using Bonferroni tests and significance level was set at P≤0.05. Findings: Moisture content of the composite flours ranged from 10.87 to12.55% and was significantly different (p<0.05). Ash content was not significantly different (p<0.05) and ranged between 1.08 and 1.85%. The fat content ranged between 5.38 and 10.67%; with AT4 having the highest and AT5 having the least fat content. The carbohydrate content was significantly (p<0.05) different among the flour; ranging between 66.65 and 73.51%. Crude fibre ranged between 1.42 and -2.20%, whereas the protein content ranged from 6.88 to 7.73%. Iron content ranged between 0.06 and 0.08 mg/100g zinc ranged from 0.19 to 0.56 mg/100g. The phosphorus content ranged from 0.07 to 0.18 mg/100g with no significant (p<0.05) difference. The calcium content was significantly (p<0.05) different among the flours and ranged from 1.41 to 1.91 mg/100g. Conclusion: The results show that the flour composites have the potential to improve nutritional status of consumers. Thus, consumption of AT1, AT4 and AT5 composite flours with a protein content of 7.3%, 7.7% and 7.4% maybe recommended for children aged 6 - 59 months in order to prevent protein-energy malnutrition.

Experimental evolution of post-ingestive nutritional compensation in response to a nutrient-poor diet.

The geometric framework of nutrition predicts that populations restricted to a single imbalanced diet should evolve post-ingestive nutritional compensation mechanisms bringing the blend of assimilated nutrients closer to physiological optimum. The evolution of such nutritional compensation is thought to be mainly driven by the ratios of major nutrients rather than overall nutritional content of the diet. We report experimental evolution of divergence in post-ingestive nutritional compensation in populations of Drosophila melanogaster adapted to diets that contained identical imbalanced nutrient ratios but differed in total nutrient concentration. Larvae from ‘Selected’ populations maintained for over 200 generations on a nutrient-poor diet with a 1 : 13.5 protein : carbohydrate ratio showed enhanced assimilation of nitrogen from yeasts and reduced assimilation of carbon from sucrose than ‘Control’ populations evolved on a diet with the same nutrient ratio but fourfold greater nutrient concentration. Compared to the Controls, the Selected larvae also accumulated less triglycerides relative to protein. This implies that the Selected populations evolved a higher assimilation rate of amino acids from the poor imbalanced diet and a lower assimilation of carbohydrates than Controls. Thus, the evolution of nutritional compensation may be driven by changes in total nutrient abundance, even if the ratios of different nutrients remain unchanged.

ЛАПАРОСКОПИЧЕСКИЙ ГАСТРОЭНТЕРОАНАСТОМОЗ ПРИ ПОСЛЕОЖОГОВОМ ДЕКОМПЕНСИРОВАННОМ ПИЛОРОДУОДЕНАЛЬНОМ СТЕНОЗЕ

Background. A burn of the gastrointestinal tract due to the ingestion of corrosive substances is one of the most common causes leading to the development of persistent pathological changes. Objective. To analyze a clinical case of laparoscopic gastroenteroanastomosis in a patient with gastric outlet obstruction secondary to accidental acid ingestion. Material and methods. The laparoscopic gastroenteroanastomosis was successfully performed on a patient with gastric outlet obstruction secondary to accidental acid ingestion in October, 2019 at Grodno University Hospital. During the postoperative period, the patient was followed up and diagnostic observation was conducted. The patient’s medical record was analyzed as well. Results. The surgery proceeded uneventfully and lasted for 3 hours. Enteral feeding was initiated on the 3rd day after the operation and was delivered via a feeding tube using liquid diet. The postoperative period elapsed without complications. The patient was discharged from the hospital after nutritional status compensation on the 12th day after the operation. Conclusions. Laparoscopic gastroenteroanastomosis is a minimally invasive, easily tolerated and effective operation, and can be considered a good alternative to other modern surgical approaches to the treatment of post-burn pyloric stenosis.

Ant Foragers Compensate for the Nutritional Deficiencies in the Colony

Achieving nutritional homeostasis is crucial for the fitness of all living organisms [1]. Using "collective wisdom," ants have been shown to excel at making rapid and appropriate decisions under various contexts [2, 3], including foraging [4-7]. Ants often use pheromone trails to share information about food resources [8-10], a process allowing them to focus their foraging activity on the best food source available [7,11-14]. However, what constitutes the best food source depends on the nutritional context of the colony in relation to its food environment [15]. In this study, we exposed ant colonies to various nutrient deficiencies and observed their compensatory nutritional responses. Ants were deprived of carbohydrate, sterol, protein, a subset of amino acids, or a single amino acid. We found that ants were rapidly able to match their foraging decisions to their nutritional needs, even if the deficiency concerned a single amino acid. An individual-based model demonstrates that these impressive feats of nutritional compensation can emerge from the iterative process of trail-laying behavior, which relies on a simple individual decision: to eat or not to eat. Our results show that, by adjusting their feeding behavior at the individual level, ants sustain homeostasis at the colony level.

Nutritional compensation to exercise- vs. diet-induced acute energy deficit in adolescents with obesity

BackgroundTo compare the energy and macronutrient intake responses to equivalent energy deficits induced by diet (food restriction) and exercise in adolescents with obesity. MethodsFourteen 12–15years old obese adolescents completed three experimental conditions (08:00am to 07:30pm) in a randomized crossover design: i) control session (CON); ii) diet-induced 25% energy depletion (Def-EI), iii) and an exercise-induced 25% energy depletion (Def-EX). The sessions order was either CON/Def-EI/Def-EX or CON/Def-EX/Def-EI as the deficit corresponded to 25% of the energy ingested at lunch on the control day (CON) and was imposed either by exercise (Def-EX) or diet (Def-EI). Ad libitum EI and macronutrients preferences were assessed at dinner and appetite sensations assessed using visual analogue scales. ResultsMean BMI was 36.6±5.0kg/m2 (z-BMI: 2.40±0.29). The individually calibrated 25% energy deficit represented 254±92kcal. Ad libitum EI was significantly higher during both Def-EX (971±225kcal) and Def-EI (949±246kcal) compared with CON (742±297) (p<0.05). The relative energy ingested derived from fat was significantly higher on both Def-EX (36.6±10.9%) and Def-EI (36.9±13.1%) compared with CON (21.6±7.8%) (p<0.05). The energy derived from carbohydrates was significantly lower on both Def-EX (48.3±9.0%) and Def-EI (44.4±17.3%) compare with CON (61.1±10.1%) (p<0.05). Appetite sensations were not different between conditions. The induced energy deficit was negatively correlated with the ad libitum EI difference between the exercise and the control session (EI Def-EX – EI CON) (r=−0,643 p<0.05) and positively correlated with the EI difference between the dietary restriction and the control session (EI Def-EI – EI CON) (r=0,569 p<0.05). ConclusionEquicaloric exercise- or diet-induced energy deficits could lead to similar EI compensation in obese adolescents but this EI compensation might be influenced by the magnitude of the deficit.

Period-1 encodes an ATP-dependent RNA helicase that influences nutritional compensation of the Neurospora circadian clock

Mutants in the period-1 (prd-1) gene, characterized by a recessive allele, display a reduced growth rate and period lengthening of the developmental cycle controlled by the circadian clock. We refined the genetic location of prd-1 and used whole genome sequencing to find the mutation defining it, confirming the identity of prd-1 by rescuing the mutant circadian phenotype via transformation. PRD-1 is an RNA helicase whose orthologs, DDX5 [DEAD (Asp-Glu-Ala-Asp) Box Helicase 5] and DDX17 in humans and DBP2 (Dead Box Protein 2) in yeast, are implicated in various processes, including transcriptional regulation, elongation, and termination, ribosome biogenesis, and mRNA decay. Although prd-1 mutants display a long period (∼25 h) circadian developmental cycle, they interestingly display a WT period when the core circadian oscillator is tracked using a frq-luciferase transcriptional fusion under conditions of limiting nutritional carbon; the core oscillator in the prd-1 mutant strain runs with a long period under glucose-sufficient conditions. Thus, PRD-1 clearly impacts the circadian oscillator and is not only part of a metabolic oscillator ancillary to the core clock. PRD-1 is an essential protein, and its expression is neither light-regulated nor clock-regulated. However, it is transiently induced by glucose; in the presence of sufficient glucose, PRD-1 is in the nucleus until glucose runs out, which elicits its disappearance from the nucleus. Because circadian period length is carbon concentration-dependent, prd-1 may be formally viewed as a clock mutant with defective nutritional compensation of circadian period length.

Moderate stoichiometric homeostasis in the sea urchin Lytechinus variegatus: effects of diet and growth on C:N:P ratios

The influence of dietary elemental contents on consumer stoichiometry was investigated in selected and combined soft tissues (as a proxy of the whole individual) of the omnivorous sea urchin, Lytechinus variegatus. We raised urchins for 4 months in controlled seawater tanks using three different diets with different nutritional contents (from lower to higher: seagrass, red macroalgae, and a formulated diet). Individuals fed the different diets varied an average of 19.7, 19.4, and 38 % in C:N, C:P, and N:P ratios, respectively, with stronger temporal variability for C:P and N:P ratios across tissues and whole individuals. This resulted in homeostasis parameters (1/H) of −0.45, 0.09, and 0.38, respectively, for C:N, C:P, and N:P, indicative of homeostatic to weakly homeostatic organisms, at least for C:P and N:P ratios. Individuals fed the nutrient-rich formulated diet had higher growth rates (14 ± 0.83 g WW month−1) than those fed macroalgae or seagrass (9.3 ± 0.57 and 3.4 ± 0.33 g WW month−1, respectively). However, rapid body increments in more nutritional diets caused both a decrease in the %N and an increase in the %P of soft tissues, which resulted in significant but opposite effects of diet stoichiometry and growth in sea urchin C:N (R = −0.74 and R = 0.93, for diet and growth effects, respectively) and N:P ratios (R = 0.60 and R = −0.63, also, respectively, for diet and growth effects). Among potential compensatory mechanisms helping to preserve certain levels of homeostasis, ingestion rates (g WW diet per g WW of urchin) were higher for seagrass and macroalgae diets than for the nutrient-rich formulated diet. In contrast, absorption and growth efficiencies displayed significant negative associations with nutrient contents in diets and did not exhibit nutritional compensation. Overall, our results suggest that resource stoichiometry strongly determines the growth rate of individuals (R = 0.88, P < 0.01), and moderate variability in C:N:P ratios of sea urchins possibly arise from differences in the allocation of proteins and RNA to body components, similarly to what has been proposed by the growth rate hypothesis.

寄主植物轮换饲养和次生代谢物交叉涂布对棉铃虫取食的影响

Dietary mixing,which means that polyphagous animals prefer to switch the diet items during ontogeny,often affects their growth and developmental performance positively. Two hypotheses,known as nutritional compensation and toxin dilution effect,have been put forward to explain such positive effect based upon the observations of various grasshopper species. As have been demonstrated in many Lepidopterous species,however,polyphagy at the species or population levels do not necessarily imply polyphagy at the individual level,for a caterpillar often has no chance to choose among host plant species due to temporal and spatial separation. In this paper,the authors reported the larvae feeding behavior of a typical generalist species,Helicoverpa armigera( Hubner),by means of forced host-switching( at two hour interval) and crosscoating of secondary metabolites( at natural concentrations) from four common host plant species of H. armigera larvae:tobacco,hot pepper,tomato,and cotton. The results show that,in all the cases,the dietary-mixing did not significantly increase the overall leaf consumption of the fourth instar larvae,moreover,some combinations inhibited feeding amountsand others had no effect,suggesting that nutritional compensation hypothesis could not explain the dietary mixing behavior of H. armigera larvae. Both tobacco leaf and its major secondary metabolite,nicotine hydrate,significantly inhibited the leaf consumption of all the other host species,while neither hot pepper leaf nor its secondary metabolite,( E)-capsaicin,showed effect on feeding amounts of all the other host species. Although tomato leaf in dietary-switching groups did not affect the consumptions of all the other three host leaves,α-tomatine showed significant feeding deterrence when coated on the leaf of hot pepper or cotton. The consumption of tobacco leaf discs increased in cotton-tobacco switching group compared with that in tobacco non-switching group,but the coating of( +)-gossypol on tobacco leaf discs decreased the feeding amounts.Cotton and hot pepper leaf showed no significant interactive effect,neither in force-switching bioassay nor in cross-coating bioassay. Taken together,H. armigera larvae may cope with the secondary metabolites contained in their natural host plants by tolerance strategy,and the tolerance level of an individual larva is in accordance with the symmorphosis hypothesis,i.e.a certain individual larva does not necessarily evolve the mechanisms to adapt multiple secondary metabolites which derived from all the recorded host species.

HSP 47 and Angiogenic Factor Expression and Its Implication for the Healing of Periosteal Defects in the Mouse Cranium

We investigated collagen formation during healing in an experimentally-created periosteal defect site (PDS) in terms of the immunohistochemical detection of Heat Shock Protein 47 (HSP47) and α -Smooth Muscle Actin ( α -SMA) along with the histopathological observation. In addition, we investigated expression of angiogenic factors, Vascular Endothelial Growth Factor (VEGF) and von Willebrand Factor (vWF), from the viewpoint of nutritional compensation for the bone in the PDS.The histological findings showed that the PDS was filled with fibrin-like structure until 3 days postoperatively, with granulation tissue at 5 days postoperatively, and it was finally replaced by collagenous fibers. The reparative periosteum-like tissue at 84 days postoperatively, showed features similar to those of normal periosteum.HSP47 and α -SMA showed a positive reaction in fibroblast-like cells as well as immature collagen fibers in the healing process of the PDS. At 84 days after operation, some of the fibroblast-like cells in the reparative periosteum-like tissue showed a positive reaction to HSP47 and α -SMA, similar to normal periosteum.Some collagen fibers in the normal periosteum showed a positive reaction for vWF. Fibrin-like structure, granulation tissue including fibrobast-like cells and some collagen fibers in the PDS were positive for VEGF and vWF during the experimental term.In conclusion, it is suggested that periosteal defects heal with regeneration of the collagenous structure, which has a role of nourishing the corresponding bone tissue.

Sperm trading and sex roles in the hermaphroditic opisthobranch sea slug Navanax inermis : eager females or opportunistic males?

The sea slug Navanax inermis (Gastropoda, Opisthobranchia) is a well-known example of a simultaneous hermaphrodite in which mating partners trade sperm. According to previous work by others, sperm trading follows from a general preference for the female role when the expected variance in reproductive success in the male role is higher and the risk of failure therefore larger. However, this view contradicts theoretical and empirical studies of other systems, which predict a general preference for the male role; sperm trading is assumed to follow from the fact that individuals benefit from sperm receipt as a nutritional compensation for sperm investment. In this study, we investigate the behaviour of N. inermis in more detail. In addition to observations of regular pairs, we also paired individuals with a partner that had been isolated for 33 days in order to induce changes in sex-role preference in the non-isolated partner. We also collected all clutches produced throughout the study to check for signs of infertility as a consequence of allosperm depletion. Fertility of field-collected and isolated individuals suggested that sperm depletion occurs under natural conditions and may be caused by a lack of partners. Although this argues in favour of female preference, low mating rates both reduce variance in male reproductive success and remove the intent to use sperm for nutritional purposes, thus eliminating the conditions under which both hypotheses are intended to operate. The observational data indicate that animals are eager to mate as males, particularly at the beginning of a mating session. Intromissions lasted longer when a simultaneous intromission was received from the partner. Increases in intromission were recorded in non-isolated individuals with partners which were previously isolated and therefore more attractive as females. This response would not have been expected were the female role the preferred one. A summary of the arguments concerning preference for either gender suggests some preference for the male role, but indicates that sexual preferences may actually change or become neutral within an individual, even in the course of a mating session. Overall, our results clearly confirm previously published observations of sperm trading in N. inermis . © 2003 The Linnean Society of London . Biological Journal of the Linnean Society, 2003, 78 , 105 - 116. ADDITIONAL KEYWORDS: sexual conflict ‐ sexual selection ‐ Gastropoda ‐ reciprocity ‐ gamete trading ‐ sperm trading ‐ egg trading.

Phenology of Winter Moth Feeding on Common Heather: Effects of Source Population and Experimental Manipulation of Hatch Dates

1. Winter moth Operophtera brumata outbreaks on common heather Calluna vulgaris have recently caused extensive damage to moorlands in Scotland. 2. The importance of synchrony between O. brumata hatching and C. vulgaris bud-burst in determining subsequent larval survival and development was investigated. 3. Heather-feeding O. brumata populations hatched at least 15 days in advance of an oak-feeding population, and achieved close synchrony with the onset of C. vulgaris shoot growth. 4. Heather-feeding O. brumata biotypes showed significantly greater survival rates than oak-feeding biotypes on C. vulgaris. 5. Experimental delay of O. brumata hatching by 30 days resulted in no drop in larval survival or developmental performance on C. vulgaris, despite a decline in foliar nitrogen concentration over this time. 6. Nutritional compensation mechanisms may explain the apparent insensitivity of O. brumata development to host-plant phenology and nitrogen content.

Tannic Acid, Protein, and Digestible Carbohydrate: Dietary Imbalance and Nutritional Compensation in Locusts

The combined effects of dietary imbalance and the allelochemical tannic acid on fifth stadium Locusta migratoria were investigated. In a factorial—design experiment, insects were fed artificial diets containing digestible carbohydrates and proteins in equal proportions (14 or 28%), or in a 1:2 or 2:1 ratio, with or without 10% tannic acid. Growth, consumption, and utilization efficiencies were measured over the course of the fifth stadium, and histological analyses of the midguts of newly molted adults were undertaken. While the consumption of diet was higher on the 14%—protein diets, consumption of protein remained lower than on the 28%—protein diets, indicating that compensatory feeding for protein was incomplete. Similarly, compensation for low dietary carbohydrates occurred, but was incomplete. Low levels of either nutrient resulted in increased intake of the other, but the effect of protein on carbohydrate intake was stronger than vice versa. There was a statistically interactive effect of carbohydrate and protein on the amounts of carbohydrate consumed, resulting from the fact that particularly high levels of carbohydrate were consumed when the diets simultaneously contained 28% carbohydrate and 14% protein. The terms "incidental augmentation" and "incidental restriction" of intake are introduced to describe the ways that certain nutrient groups may affect the intake of others in foods that are nutritionally imbalance. Tannic acid resulted in reduced efficiency of conversion of ingested nitrogen, but the efficiency of conversion of total ingested nutrients was higher on the diets containing tannic acid. A higher frequency of lesions was observed in the midgut epithelia of tannin—fed insects than controls, and it is suggested that the sloughing of necrotic epithelial tissues into the lumen and their subsequent egestion with the feces may account for the reduced efficiency of nitrogen conversion in these insects. A statistical interaction between protein levels and tannic acid demonstrated that tannic acid reduced consumption, but only of the low protein diets. Therefore, the effect of tannic acid was to restrict compensatory feeding for protein. A consequence of this was reduced growth in insects fed low—protein diets containing tannic acid. Total growth (dry mass) was lower on the 28%—protein diets and higher on the 28%—carbohydrate diets, and therefore corresponded with levels of carbohydrate intake. Nitrogen accumulation increased with dietary protein levels, but remained constant across carbohydrate levels despite increased intake of nitrogen on low—carbohydrate diets. This was accounted for by lower efficiency of conversion of nitrogen on the 14%—carbohydrate diets. Approximate digestibility was higher for the 14%—protein diets, possibly reflecting increased intake of easily digested carbohydrates. There were no statistically significant interactive effects between the two nutrients, or between either nutrient and tannic acid, on utilization efficiencies.