Changes In Feeding Behavior Research Articles

350 Effects of Adding Yeast Derivatives to High Concentrate Diets on Performance and Feeding Behavior of Beef Cattle Finished in Feedlot

Abstract Yeast derivatives enhance beef cattle performance (Torres et al., 2022), allowing farmers to increase feedlot financial income. However, yeast derivatives vary on yeast species, grown medium, purity, technological processing, yeast cell parts marketed.Thus, in these experiments, we aimed to understand the potential of different yeast derivatives to manipulate performance, feed intake, and feeding behavior. In experiment 1, 1,760 non-castrated males were used to study performance and feed intake. These animals were distributed in large pens, mimicking actual feedlot operations. In xperiment 2, 96 animals with radio frequency identification ear tags were allocated in small groups with induvial access to automatic feeders equipped with scales to study daily individual feeding behavior. Animals were allocated to four treatments: 1) Control, no yeast derivative; 2) AY - 7g/animal/day, autolyzed Saccharomyces cerevisiae grown on sugarcane molasses, RumenYeast (ICC, São Paulo, Brazil); 3) YM - 3g/animal day, yeast rich in soluble yeast metabolites; 4) YB - 5g/animal/day, yeast blend (live Yeast plus autolyzed Yeast. Orthogonal contrasts were performed comparing control against AY, YM, and YB. Differences were declared significant at P < 0.05 and as a trend when 0.05 < P < 0.10. Pen was considered as the experimental unit for experiment 1. For experiment 2, animals were considered the experimental unit. Regarding experiment 1, AY tended to increase adjusted average daily gain and hot carcass weight (Table 1). Dry matter intake did not differ between treatments in experiment 1 (large pen trial). Looking at individual intake data, experiment 2, feeding behavior and water intake changed when yeast derivatives were included in the diet. In general, animals supplemented with AY spent less time eating, which was more evident in the adaptation period (Table 1). AY and YB had stimulated feed intake in some periods of experiment 2. However, the evident less time spent eating by the AY group promoted a greater feeding rate (kg ingested/min) markedly compared with YM and YB, but in general, also greater than control. Considering the initial period of feedlot operations, this greater feeding rate could favor animals supplemented with AY to adapt faster to feedlot diet/feeding conditions. All yeast derivatives increased water intake. In summary, autolyzed Saccharomyces cerevisiae grown on sugarcane molasses increased beef cattle performance and feeding rate. This change in feeding behavior may accelerate the adaptation of beef cattle in the transition from the backgrounding phase to the feedlot operation.

Early-life sodium deprivation programs long-term changes in ingestive behaviors and energy expenditure in C57BL/6J mice.

Postnatal growth failure remains a significant problem for infants born prematurely, despite aggressive efforts to improve perinatal nutrition. Though often dysregulated in early life when children are born preterm, sodium (Na) homeostasis is vital to achieve optimal growth. We hypothesize that insufficient Na supply in this critical period contributes to growth restriction and programmed risks for cardiometabolic disease in later adulthood. Thus, we sought to ascertain the effects of prolonged versus early-life Na depletion on weight gain, body composition, food and water intake behaviors, and energy expenditure in C57BL/6J mice. In one study, mice were provided a low (0.04%)- or normal/high (0.30%)-Na diet between 3 and 18 wk of age. Na-restricted mice demonstrated delayed growth and elevated basal metabolic rate. In a second study, mice were provided 0.04% or 0.30% Na diet between 3 and 6 wk of age and then returned to standard (0.15%)-Na diet through the end of the study. Na-restricted mice exhibited growth delays that quickly caught up on return to standard diet. Between 6 and 18 wk of age, previously restricted mice exhibited sustained, programmed changes in feeding behaviors, reductions in total food intake, and increases in water intake and aerobic energy expenditure while maintaining normal body composition. Although having no effect in control mice, administration of the ganglionic blocker hexamethonium abolished the programmed increase in basal metabolic rate in previously restricted mice. Together these data indicate that early-life Na restriction can cause programmed changes in ingestive behaviors, autonomic function, and energy expenditure that persist well into adulthood.

SAT602 The Regulation Of Food Intake Via Gastrointestinal Receptors

Abstract Disclosure: M.M. Bethea: None. S. da Silva Teixeira: None. T.M. Cook: None. M. Mommandi: None. G. Nault: None. D. Sandoval: None. Obesity is a global pandemic characterized by excessive fat storage due to an imbalance in energy homeostasis. This metabolic imbalance is driven by increased energy intake relative to energy expenditure. The gut vagal afferent neurons play a critical role in energy homeostasis by sensing the various chemo- and mechano-signals resulting from ingested nutrients and initiating changes in feeding behavior. However, these neurons fail to respond adequately in the context of diet-induced obesity, leading to overeating and ultimately obesity. Bariatric surgeries, which modify the anatomy of the gut, are currently the most effective but also the most invasive treatments for obesity. The mechanism(s) by which bariatric surgery modulates metabolic processes is still not fully understood. The vertical sleeve gastrectomy (VSG) procedure, a bariatric surgery where 80% of the stomach is removed, alters feeding patterns and induces sustained weight loss. Our findings demonstrate that VSG induces alterations in the signals in the gut-brain-axis, resulting in increased activation of the nucleus of the solitary tract (NTS) - a brain region critical for integrating peripheral signals and regulating food intake. Importantly, emerging data demonstrate that neurons that sense intestinal distension play a critical role in the regulation of feeding. We hypothesized that diet induced obesity attenuates intestinal-stretch inhibition of food intake and that VSG restores it. Using non-nutritive substances such as methylcellulose and mannitol to differentiate stomach versus intestinal stretch respectively, we demonstrate that high-fat diet feeding ablates intestinal stretch-induced reductions in food intake while weight loss via dietary intervention, restores this response. More importantly, VSG restores intestinal stretch-induced food intake reduction, suggesting the reactivation of the peripheral neurons that detect intestinal stretch. Taken together, our data provide evidence that VSG alters the signals in the gut-brain-axis by creating an environment where intestinal distension is exaggerated. This effect likely contributes to the sustained weight loss and alterations in feeding patterns observed after VSG. Our findings have important implications for the development of less invasive therapies for obesity that target the gut-brain-axis and feeding behavior. Presentation: Saturday, June 17, 2023

Exposure to high-sugar diet induces transgenerational changes in sweet sensitivity and feeding behavior via H3K27me3 reprogramming.

Human health is facing a host of new threats linked to unbalanced diets, including high sugar diet (HSD), which contributes to the development of both metabolic and behavioral disorders. Studies have shown that diet-induced metabolic dysfunctions can be transmitted to multiple generations of offspring and exert long-lasting health burden. Meanwhile, whether and how diet-induced behavioral abnormalities can be transmitted to the offspring remains largely unclear. Here, we showed that ancestral HSD exposure suppressed sweet sensitivity and feeding behavior in the offspring in Drosophila. These behavioral deficits were transmitted through the maternal germline and companied by the enhancement of H3K27me3 modifications. PCL-PRC2 complex, a major driver of H3K27 trimethylation, was upregulated by ancestral HSD exposure, and disrupting its activity eliminated the transgenerational inheritance of sweet sensitivity and feeding behavior deficits. Elevated H3K27me3 inhibited the expression of a transcriptional factor Cad and suppressed sweet sensitivity of the sweet-sensing gustatory neurons, reshaping the sweet perception and feeding behavior of the offspring. Taken together, we uncovered a novel molecular mechanism underlying behavioral abnormalities spanning multiple generations of offspring upon ancestral HSD exposure, which would contribute to the further understanding of long-term health risk of unbalanced diet.

Operant Training for Highly Palatable Food Alters Translating Messenger RNA in Nucleus Accumbens D2 Neurons and Reveals a Modulatory Role of Ncdn

BackgroundHighly palatable food triggers behavioral responses including strong motivation. These effects involve the reward system and dopamine neurons, which modulate neurons in the nucleus accumbens (NAc). The molecular mechanisms underlying the long-lasting effects of highly palatable food on feeding behavior are poorly understood. MethodsWe studied the effects of 2-week operant conditioning of mice with standard or isocaloric highly palatable food. We investigated the behavioral responses and dendritic spine modifications in the NAc. We compared the translating messenger RNA in NAc neurons identified by the type of dopamine receptors they express, depending on the kind of food and training. We tested the consequences of invalidation of an abundant downregulated gene, Ncdn. ResultsOperant conditioning for highly palatable food increased motivation for food even in well-fed mice. In wild-type mice, free choice between regular and highly palatable food increased weight compared with access to regular food only. Highly palatable food increased spine density in the NAc. In animals trained for highly palatable food, translating messenger RNAs were modified in NAc neurons expressing dopamine D2 receptors, mostly corresponding to striatal projection neurons, but not in neurons expressing D1 receptors. Knockout of Ncdn, an abundant downregulated gene, opposed the conditioning-induced changes in satiety-sensitive feeding behavior and apparent motivation for highly palatable food, suggesting that downregulation may be a compensatory mechanism. ConclusionsOur results emphasize the importance of messenger RNA alterations in D2 striatal projection neurons in the NAc in the behavioral consequences of highly palatable food conditioning and suggest a modulatory contribution of Ncdn downregulation.

Long-term regulation of fat sensing in rainbow trout (Oncorhynchus mykiss) fed a vegetable diet from the first feeding: focus on free fatty acid receptors and their signalling.

Taste plays a fundamental role in an animal’s ability to detect nutrients and transmits key dietary information to the brain, which is crucial for its growth and survival. Providing alternative terrestrial ingredients early in feeding influences the growth of rainbow trout (RT, Oncorhynchus mykiss). Thus, the present study aimed to assess the influence, via long-term feeding (from the first feeding to 8 months), of alternative plant ingredients (V diet for vegetable diet v. C diet for a control diet) in RT on the mechanism of fat sensing at the gustatory level. After the feeding trial, we studied the pathways of the fat-sensing mechanism in tongue tissue and the integrated response in the brain. To this end, we analysed the expression pattern of free fatty acid receptors (ffar) 1 and 2, markers of calcium-signalling pathways (phospholipase Cβ, Orai, Stim or Serca), the serotonin level (a key neurotransmitter in taste buds) and the expression pattern of appetite-regulating neuropeptides in the hypothalamus (central area of appetite regulation). The results revealed that the V diet modified the expression pattern of ffar1 and paralogs of ffar2 genes in tongue tissue, along with differential regulation of calcium-signalling pathways and a defect in serotonin level and brain turnover, without influencing neuropeptide expression. This study is the first to support that changes in feeding behaviour of RT fed a V diet could be due to the difference in nutrient sensing and a decrease in hedonic sensation. We revealed that RT have similar fat-detection mechanisms as mammals.

Dietary Challenges for Parasitoid Wasps (Hymenoptera: Ichneumonoidea); Coping with Toxic Hosts, or Not?

Many insects defend themselves against predation by being distasteful or toxic. The chemicals involved may be sequestered from their diet or synthesized de novo in the insects' body tissues. Parasitoid wasps are a diverse group of insects that play a critical role in regulating their host insect populations such as lepidopteran caterpillars. The successful parasitization of caterpillars by parasitoid wasps is contingent upon their aptitude for locating and selecting suitable hosts, thereby determining their efficacy in parasitism. However, some hosts can be toxic to parasitoid wasps, which can pose challenges to their survival and reproduction. Caterpillars employ a varied array of defensive mechanisms to safeguard themselves against natural predators, particularly parasitoid wasps. These defenses are deployed pre-emptively, concurrently, or subsequently during encounters with such natural enemies. Caterpillars utilize a range of strategies to evade detection or deter and evade attackers. These tactics encompass both measures to prevent being noticed and mechanisms aimed at repelling or eluding potential threats. Post-attack strategies aim to eliminate or incapacitate the eggs or larvae of parasitoids. In this review, we investigate the dietary challenges faced by parasitoid wasps when encountering toxic hosts. We first summarize the known mechanisms through which insect hosts can be toxic to parasitoids and which protect caterpillars from parasitization. We then discuss the dietary adaptations and physiological mechanisms that parasitoid wasps have evolved to overcome these challenges, such as changes in feeding behavior, detoxification enzymes, and immune responses. We present new analyses of all published parasitoid-host records for the Ichneumonoidea that attack Lepidoptera caterpillars and show that classically toxic host groups are indeed hosts to significantly fewer species of parasitoid than most other lepidopteran groups.

A STIM dependent dopamine-neuropeptide axis maintains the larval drive to feed and grow in Drosophila.

Appropriate nutritional intake is essential for organismal survival. In holometabolous insects such as Drosophila melanogaster, the quality and quantity of food ingested as larvae determines adult size and fecundity. Here we have identified a subset of dopaminergic neurons (THD') that maintain the larval motivation to feed. Dopamine release from these neurons requires the ER Ca2+ sensor STIM. Larvae with loss of STIM stop feeding and growing, whereas expression of STIM in THD' neurons rescues feeding, growth and viability of STIM null mutants to a significant extent. Moreover STIM is essential for maintaining excitability and release of dopamine from THD' neurons. Optogenetic stimulation of THD' neurons activated neuropeptidergic cells, including median neuro secretory cells that secrete insulin-like peptides. Loss of STIM in THD' cells alters the developmental profile of specific insulin-like peptides including ilp3. Loss of ilp3 partially rescues STIM null mutants and inappropriate expression of ilp3 in larvae affects development and growth. In summary we have identified a novel STIM-dependent function of dopamine neurons that modulates developmental changes in larval feeding behaviour and growth.

A potential role for GPR160 and its ligand, CART, in the modulation of feeding behavior in Prader-Willi Syndrome

Hyperphagia is a hallmark of Prader-Willi syndrome (PWS). Managing the extreme hunger and insatiability associated with PWS remains a considerable challenge to PWS patients and their caregivers. Appetite and feeding behavior are governed by numerous neural circuits, several of which are potentially disrupted when some or all of the Prader-Willi critical region on chromosome 15 is lost. Previous research has focused on well-established feeding circuits in an effort to uncover the physiology underlying PWS hyperphagic behavior; however, due to the complex interplay between these circuits, much is left to be explored. We have previously demonstrated that interactions between GPR160 and its ligand cocaine and amphetamine regulated transcript (CART) are important in the control of feeding behavior. Several groups have reported that CART exerts anorexigenic properties when injected into areas of the brain that are important to feeding behavior, including regions of the brainstem and hypothalamus. The prohormone convertase PSCK1, which is responsible for post-translational processing of the CART prohormone, appears to be reduced in PWS patients, suggesting that CART could play a role in the pathophysiology of PWS. Using a rat model of PWS supplied by the Foundation for Prader-Willi Research (Magel2- deficient), we seek to investigate this potential role of CART and GPR160 in PWS-associated hyperphagia. Through the use of continuous monitoring of food and water intake, we were able to define meal patterning differences between wild type and paternally Magel2-deficient rats. In addition to evaluating baseline meal patterning, we also administered CART centrally and recorded CART-induced changes in feeding behavior. Lastly, we determined physiologic changes in levels of GPR160, CART, and PSCK1 in the pituitary, hypothalamus, amygdala, and brainstem from WT and paternally-deficient Magel2 rats in the setting of metabolic stress (fasting). Although additional studies must be performed to better define the role of CART and GPR160 in the feeding behavior of PWS patients, we anticipate that this ligand-receptor pair has the potential to serve as a novel therapeutic target for the treatment of PWS-associated hyperphagia. Foundation for Prader-Willi Research 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.

Are Caterpillars Evolving Through Feeding Behavior in Response to Parasitoids?

Cabbage loopers (Trichoplusia ni) are herbivores that are commonly preyed upon by many different species of parasitoid wasps. These wasps reproduce by injecting its gestated eggs into 2-3rd instar caterpillars. After injection of wasp eggs, studies have shown some caterpillars will shift behavior in reaction to the injection. The result of the hatching eggs is termination of the caterpillar. I specifically look at this feeding behavior in the caterpillar after injection, using different phytochemically active plant species to show that there is a conscious attempt at self-medication from the caterpillars. This is extremely important as the trophic effect that herbivores have on the local plant competition, especially between native and non-native plant species, which create a domino effect on the entire ecosystem and its survival. We use two different phytochemically active plant species: Nasturtium officinale, a phytochemically rich plant, and Mimulus guttatus, a phytochemically benign plant. We then measured the percent consumed on a given leaf, before and after injection of a silica bead into 4-5th instar cabbage loopers, using different injection type groups totaling 65 caterpillars each assigned to one specific plant individual that it will feed on for the duration of the experiment. For the percent of leaf consumed, injection type was not significantly different. Caterpillars that were stabbed but not injected (SN) were significantly different than those that were not stabbed. Plant type and plant type with an interaction term of injection type were not significantly different in percent of leaf tissue consumed. Suggesting no preference in diet, or respective feeding behavior change.

The effects of kisspeptin-type neuropeptides on feeding behavior and intestinal metabolism in the sea cucumber, Apostichopus japonicus

Kisspeptin neuropeptides encoded by the kiss-1 gene are endogenous ligands corresponding to G-protein-coupled receptor 54. It has been confirmed that kisspeptin neuropeptides (AjK1 and AjK2) exist in Apostichopus japonicus and participate in reproductive and metabolic regulation. In this study, changes in feeding behavior and intestinal metabolic physiology of A. japonicus after the administration of differing concentrations (0.1 μM, 1 μM, 10 μM) and types of kisspeptin neuropeptides (AjK1 and AjK2) were studied. The results revealed that both AjK1 and AjK2 are involved in the regulation of feeding behavior in A. japonicus as significant inhibition was observed at concentrations of 1 μM and 10 μM AjK1 and 10 μM AjK2. It thus appears that kisspeptin neuropeptides mainly inhibit feeding by reducing feeding time in A. japonicus. Levels of l-carnitine, phosphatidylcholine, prostaglandin, and other metabolites in the intestine of A. japonicus treated with kisspeptin neuropeptides differed significantly from those of the control, which may explain the observed changes in feeding behavior.

Natural variation in host feeding behaviors impacts host disease and pathogen transmission potential.

Animals ranging from mosquitoes to humans often vary their feeding behavior when infected or merely exposed to pathogens. These so-called "sickness behaviors" are part of the innate immune response with many consequences, including avoiding orally transmitted pathogens. Fully understanding the role of this ubiquitous behavior in host defense and pathogen evolution requires a quantitative account of its impact on host and pathogen fitness across environmentally relevant contexts. Here, we use a zooplankton host and fungal pathogen as a case study to ask if infection-mediated feeding behaviors vary across pathogen exposure levels and natural genetic variation in susceptibility to infection. Then, we connect these changes in behavior to pathogen transmission potential (spore yield) and fitness and growth costs to the host. Our results validate a protective effect of altered feeding behavior during pathogen exposure while also revealing significant variation in the magnitude of this response across host susceptibility and pathogen exposure levels. Across all four host genotypes, feeding rates were negatively correlated with susceptibility to infection and transmission potential. The most susceptible genotypes exhibited either strong anorexia, reducing food intake by 26%-42%, ("Standard") or pronounced hyperphagia, increasing food intake by 20%-54% ("A45"). Together, these results suggest that infection-mediated changes in host feeding behavior-which are traditionally interpreted as immunopathology-may in fact serve as crucial components of host defense strategiesandwarrantfurtherinvestigation.

Time allocation and diving behaviour of harbour porpoises (Phocoena phocoena) in Danish and adjacent waters

To gain insight into the time allocation and diving behaviour of harbour porpoises in Danish and adjacent waters, satellite linked dive recorders were mounted on 14 harbour porpoises. The animals were incidentally caught alive by fishermen using pound nets during 1997- 99 in the Danish Belt seas. Information on diving behaviour was collected from April to November. Contact with individual porpoises remained for up to 130 days. The average number of dives per hour was 29 during April-August and 43 during October-November. Daily maximum dive depth corresponds to the depth of the Belt seas and Kattegat where depth generally does not exceed 50m. Maximum dive depth recorded was 132m from animals moving north into Skagerrak. Dives were frequently recorded in the category 10-15min, but could potentially be an artefact of the sampling regime. The diurnal pattern shows that harbour porpoises dive continuously both day and night, but with peak activity during daylight hours. On average they spent 55% of their time in the upper 2m during April-August. These values have implications for aerial abundance surveys when correcting for animals not visible. A mature female and its approximately 10 months old calf were both tagged and swam together for 43 days until contact was lost. The calf made more frequent but shorter dives than the mature female. The number of dives per hour decreased, while the dive depth and duration increased for both animals from May to June, suggesting a change in feeding behaviour. It is not known whether the female and calf synchronised their dives, but the diurnal dive pattern shows a correlated dive rhythm in May, but not in June. This change in mother-calf behaviour suggests that the calf foraged more independently, corresponding to the time of year when porpoise calves leave their mother.

Tropicalization shifts herbivore pressure from seagrass to rocky reef communities.

Climate-driven species redistributions are reshuffling the composition of marine ecosystems. How these changes alter ecosystem functions, however, remains poorly understood. Here we examine how impacts of herbivory change across a gradient of tropicalization in the Mediterranean Sea, which includes a steep climatic gradient and marked changes in plant nutritional quality and fish herbivore composition. We quantified individual feeding rates and behaviour of 755 fishes of the native Sarpa salpa, and non-native Siganus rivulatus and Siganus luridus. We measured herbivore and benthic assemblage composition across 20 sites along the gradient, spanning 30° of longitude and 8° of latitude. We coupled patterns in behaviour and composition with temperature measurements and nutrient concentrations to assess changes in herbivory under tropicalization. We found a transition in ecological impacts by fish herbivory across the Mediterranean from a predominance of seagrass herbivory in the west to a dominance of macroalgal herbivory in the east. Underlying this shift were changes in both individual feeding behaviour (i.e. food choice) and fish assemblage composition. The shift in feeding selectivity was consistent among temperate and warm-affiliated herbivores. Our findings suggest herbivory can contribute to the increased vulnerability of seaweed communities and reduced vulnerability of seagrass meadows in tropicalized ecosystems.

Oral Stimulation by 3-D Printed Speech-sensory Appliance Series to Evaluate Speech and Associated Oral Sensory Difficulties in Children with Autism Spectrum Disorder: Protocol for Randomised Controlled Trial

Introduction: Oral sensory problems in Autism Spectrum Disorder (ASD) are mainly due to lack of sensory-motor synchronisation and incomplete neuromuscular development. Direct oral stimulation can play a significant role as a part of oral therapy, because the speech outcome by Speech Therapy (ST) has subjective variation and requires a long period of time. The other oral muscular therapy has lack of specificity and sensitivity. However, the direct oral stimulation in the form of appliance therapy has not yet been investigated. Aim: To explore the precise role of Speech-sensory Appliance (SSA) on speech disorder and associated oral sensory problems in ASD children. Materials and Methods: In this single-arm, Randomised Controlled Trial (RCT), 40 ASD-diagnosed children between the ages of 4 and 11 will be involved. The study participants will be split into two groups of 20 each at random. While the other group will be exposed to SSA+ST therapy, one of the groups will undergo SSA therapy. The speech therapist was unaware of the group of children who received both therapies (blind). Analyses of the results will be conducted utilising voice recordings and Visual Analogue Scales (VAS). Before and after therapy, the voice recording graph will be collected. Parents will be given a short questionnaire as part of the VAS to track any changes in feeding behaviour. Expected Results: SSA therapy that is 3D printed will result in better speaking outcomes and feeding behaviour. Conclusion: If the current study’s hypothesis is confirmed, direct oral stimulation can be employed either alone or in conjunction with ST to improve participants with ASD’s speech outcomes and feeding behaviour.

Changing feeding habits and ontogenetic dimorphism in juveniles and adults Aplysia punctata (Cuvier, 1803) (Mollusca, Gastropoda, Heterobranchia) in the Mediterranean Sea

Specimens of Aplysia punctata inhabiting the Catalonian coast (NE Spain, Western Mediterranean Sea) display two different color patterns, which have been thought to represent two distinct species. However, molecular analyses conducted by other authors and confirmed herein show that there are no genetic differences between individuals of the two color morphs. At the same time, these color morphs display distinct life history traits, including different size, mating behavior, and egg mass and larvae coloration. In this paper, it is hypothesized that distinct diets are responsible of these differences. The results of this study confirm that small red specimens of A. punctata feed on red algae and primarily Sphaerococcus coronopifolius and Plocamium cartilagineum; pigments from these algae give small specimens of A. punctata a very similar morphological appearance to adults of the Aplysia parvula species complex. In contrast, adult specimens of A. punctata feed preferentially on green algae of the species Ulva lactuca. This change in feeding behavior is probably related to defensive strategies involving camouflage. In addition, the egg masses take on a pink to reddish color that is retained in the larval stage of A. punctata juveniles.

Feeding behavior, microcystin accumulation, biochemical response, and ultramicrostructure changes in edible freshwater bivalve Corbicula fluminea exposed to Microcystis aeruginosa.

As filter-feeders, bivalves naturally come into direct contact with microcystins (MCs) in eutrophic water bodies suffering from cyanobacteria blooms. To date, however, no studies have quantified the dynamics of microcystin accumulation and depuration in the edible freshwater bivalve Corbicula fluminea when exposed to dense bloom concentrations of Microcystis aeruginosa, while considering dynamic changes of biochemical indexes and feeding structure. In the present study, the bioaccumulation and detoxification of microcystin-LR (MC-LR) in C. fluminea were investigated. Our results showed that C. fluminea would graze equally efficiently on green algae and M. aeruginosa, irrespective of whether the M. aeruginosa strains were toxic or non-toxic. MCs could be accumulated and depurated by C. fluminea efficiently. In addition, linear and exposure time-dependent MC-LR accumulation patterns were observed in C. fluminea. Activities of biotransformation (glutathione S-transferase, GST) and antioxidant enzymes (superoxide dismutase, SOD, and catalase, CAT) and malondialdehyde (MDA) contents in various tissues of treated clams were stimulated by MCs in a tissue-specific manner. Our findings indicated that C. fluminea hepatopancreas was the primary target organ for MC-LR detoxification processes, as evidenced by a significant increase in GST activity. Besides, gills and mantle were more sensitive than the other tissues to oxidative stress in the initial microcystin exposure period with a significant increase in SOD activity. The scanning electron microscopy (SEM) observations revealed that the lateral cilia in the gill aperture were well developed during the MCs exposure period, which could perform the filter-feeding function instead of the damaged frontal cilium. This study provides insight into the possible tolerance of C. fluminea exposed to dense bloom concentrations of M. aeruginosa.

Bta06987, Encoding a Peptide of the AKH/RPCH Family: A Role of Energy Mobilization in Bemisia tabaci.

Simple SummaryBta06987 gene encodes a peptide that belongs to the AKH/RPCH family. Members of this family exert essential effects on energy metabolism and other physiological and biological processes. Bemisia tabaci is a crop pest, causing crop losses mainly through feeding and transmission of plant viruses. There are only a few reports about AKH family in B. tabaci. In our study, we report on the characterization of the neuropeptide precursor encoded by Bta06987 in B. tabaci at the molecular level and provide evidence for its essential function in energy homeostasis. Moreover, through an electrical penetration graph experiment, we found that manipulation of the relative expression of Bta06987 effected the feeding behavior of B. tabaci. The findings in this paper can be used toward developing strategies aimed at decreasing the feeding time of B. tabaci, which might be useful for controlling pests and plant virus transmission.A neuropeptide precursor encoded by Bta06987 associates with AKH neuropeptide. In the AKH/RPCH family, these members have been demonstrated to participate in energy mobilization in many insects. In our research, the Bta06987 gene from Bemisia tabaci was cloned, and the amino acid sequence analysis was performed. During the starvation of B. tabaci, the mRNA level of Bta06987 showed a significant elevation. We investigated the functions of Bta06987 in B. tabaci using RNA interference (RNAi), and the adult females of B. tabaci after being fed with dsBta06987 showed a higher glycogen and triglyceride levels and lower trehalose content than the control. Furthermore, in the electrical penetration graph (EPG) experiment, B. tabaci showed changes in feeding behavior after feeding with dsBta06987, such as the reduction in parameters of E waveform percentage and total feeding time. Our findings might be helpful in developing strategies to control pest and plant virus transmission.

Long-term changes in oral feeding behaviors of growing rats.

Oral feeding is critical for survival in both humans and animals. However, few studies have reported quantitative behavioral measures associated with the development of oral feeding behaviors. Therefore, the present study investigated developmental changes in the oral feeding behaviors of rats by quantitatively assessing pasta eating and licking behaviors. In the pasta eating test, the time to finish pasta sticks of three different thicknesses (Φ = 0.9, 1.4, and 1.9mm, 4cm long) was recorded between postnatal day 29 (P29) and P49, because all rats were able to finish eating these pasta sticks on P29. A developmental decrease in the time to finish pasta sticks of all thicknesses was observed during the initial period of recordings and plateaued before P35. The extent of this decrease was dependent on the thickness of pasta sticks. In the licking test, the number of licks per 10s and the total intake volume during the test were recorded between P19 and P49, because all rats were able to access and lick the solution on P19. The time courses of developmental increases in the number of licks and the total intake volume were similar to the results obtained in the pasta eating test. Collectively, these results suggest that developmental changes in pasta eating and licking behaviors markedly differed between the weanling and periadolescent periods. The present study also demonstrated the applicability of the pasta eating and licking tests to the quantification of developmental changes in the oral feeding behaviors of rats.

Feeding behavior innovation increases foraging efficiency in the Amur falcon but may be a threat to Asian particolored bats.

Behavioral innovations are rare and infrequent in the natural world, but they are pivotal for animals to respond to environmental changes. The ecological benefits of these innovations remain unknown, especially in wild populations. Here, two foraging strategies and three eating behaviors of the Amur falcon (Falco amurensis) were observed during predation on Asian particolored bats (Vespertilio sinensis) across 3 years. We demonstrated that an eating behavioral innovation in F. amurensis increased the foraging efficiency of V. sinensis more than twofold during 3 consecutive years. This showed that changes in feeding behavior by a bird strongly influenced the rate of energy intake. Since predation on bats by falcons mainly occurred during the lactation and post‐lactation of bats, this may have a certain level of negative effect on the bat population.