Regulation Of Feeding Research Articles

Astrocytic Dagla Deletion Decreases Hedonic Feeding in Female Mice.

Introduction: Endocannabinoids and exogenous cannabinoids are potent regulators of feeding behavior and energy metabolism. Stimulating cannabinoid receptor signaling enhances appetite, particularly for energy-dense palatable foods, and promotes energy storage. To elucidate the underlying cellular mechanisms, we investigate here the potential role of astrocytic endocannabinoid 2-arachidonoylglycerol (2-AG). Astrocytes provide metabolic support for neurons and contribute to feeding regulation but the effect of astrocytic 2-AG on feeding is unknown. Materials and Methods: We generated mice lacking the 2-AG synthesizing enzyme diacylglycerol lipase alpha (Dagla) in astrocytes (GLAST-Dagla KO) and investigated hedonic feeding behavior in male and female mice. Body weight and baseline water and food intake was characterized; additionally, the mice went through milk, saccharine, and sucrose preference tests in fed and fasted states. In female mice, the estrous cycle stages were identified and plasma levels of female sex hormones were measured. Results: We found that the effects of the inducible astrocytic Dagla deletion were sex-specific. Acute milk preference was decreased in female, but not in male mice and the effect was most evident in the estrus stage of the cycle. This prompted us to investigate sex hormone profiles, which were found to be altered in GLAST-Dagla KO females. Specifically, follicle-stimulating hormone was elevated in the estrus stage, luteinizing hormone in the proestrus, and progesterone was increased in both proestrus and estrus stages of the cycle compared with controls. Conclusions: Astrocytic Dagla regulates acute hedonic appetite for palatable food in females and not in males, possibly owing to a deregulated female sex hormone profile. It is plausible that endocannabinoid production by astrocytes at least partly contributes to the greater susceptibility to overeating in females. This finding may also be important for understanding the effects of exogenous cannabinoids on sex hormone profiles.

A feed-regulated water-only cyclone for improving the separation performance of clean coal from coal slime

Due to the challenges of separation and high costs, coal slime is often directly burned without further separation processing, leading to environmental pollution. Therefore, a feed-regulated water-only cyclone has been proposed to improve the coal slime separation efficiency by controlling the suspended bed. This method optimizes particle characteristics by incorporating a pre-desliming hydrocyclone, the characteristics of particles were optimized to regulate the hindered settling in suspension layer. Response surface experiments were conducted to investigate the impact of structural parameters on separation efficiency, Additionally, under optimal parameter conditions, particle size and density were characterized, and a simulation analysis was conducted using CFD–EDEM. The results showed that the maximum separation efficiency achieved in the experiment was 35.31%. Particle characterization analysis also revealed that, after feed regulation, the proportion of particles with a size of 0.045 mm within high density exceeded 75%. Industrial application experiments demonstrated the feasibility of obtaining a high-quality coal product with over screen yield of 9.29% and an ash content of 9.47%. This transformation of coal slurry into a valuable resource has generated significant economic benefits for enterprises and will address the environmental pollution issue caused by direct combustion and improper disposal.

Stomach clusterin as a gut-derived feeding regulator

Stomach clusterin as a gut-derived feeding regulator

Opportunities for Camelina Meal as a Livestock Feed Ingredient

Camelina sativa is an annual oilseed crop that requires low inputs. Recently, interest in camelina oil for both human use and biofuel production has increased. Camelina oil extraction is performed through two main methods, namely, mechanical expulsion and solvent extraction. The resulting meals from the oil extraction process show promise as an animal feed due to their high crude protein content. Solvent extraction removes more oil from the seed, which results in a meal that is lower in fat and higher in crude protein concentration than expelled meal (3.52 vs. 13.69% and 41.04 vs. 34.65%, respectively). Solvent-extracted camelina meal has a similar chemical composition to canola meal but less crude protein and more fiber than soybean meal. Camelina meal is also limited by its anti-nutritional factors, mainly glucosinolates. Camelina meal contains 23.10 to 44.90 mmol/kg of glucosinolates, but processing methods may be able to decrease the total glucosinolates. Heat-treating the camelina meal can decrease glucosinolates and remove residual solvent in the solvent-extracted meal. The fungal fermentation of canola meal has also decreased glucosinolates, which could be used in camelina meal as well. The selective breeding of camelina varieties to decrease glucosinolates in the plant is also a solution to the high glucosinolates found in camelina meal. Current feed regulations in the US and Canada limit camelina meal to 10% inclusion in broiler chicken, laying hen, and cattle diets.

Identification of C1q/TNF-related protein 4 as a novel appetite-regulating peptide that reduces food intake in Siberian sturgeon (Acipenser baerii)

Emerging findings point to a role for C1q/TNF-related protein 4 (CTRP4) in feeding in mammals. However, it remains unknown whether CTRP4 regulates feeding in fish. This study aimed to determine the feeding regulation function of CTRP4 in Siberian sturgeon (Acipenser baerii). In this study, the Siberian sturgeon ctrp4 (Abctrp4) gene was cloned, and Abctrp4 mRNA was shown to be highly expressed in the hypothalamus. In the hypothalamus, Abctrp4 mRNA decreased during fasting and reversed after refeeding. Subsequently, we obtained the AbCTRP4 recombinant protein by prokaryotic expression and optimized the expression and purification conditions. Siberian sturgeon (81.28 ± 14.75 g) were injected intraperitoneally using 30, 100, and 300 ng/g Body weight (BW) AbCTRP4 to investigate its effect on feeding. The results showed that 30, 100, and 300 ng/g BW of the AbCTRP4 significantly reduced the cumulative food intake of Siberian sturgeon at 1, 3, and 6 h. Finally, to investigate the potential mechanism of CTRP4 feeding inhibition, 300 ng/g BW AbCTRP4 was injected intraperitoneally. The findings demonstrated that AbCTRP4 treatment for 1 h significantly promoted the mRNA levels of anorexigenic peptides (pomc, cart, and leptin) while suppressing the mRNA abundances of orexigenic peptides (npy and agrp).In addition, the jak2/stat3 pathway in the hypothalamus was significantly activated after 1 h of AbCTRP4 treatment. In conclusion., this study confirms the anorexigenic effect of CTRP4 in Siberian sturgeon.

Small intestinal CaSR-dependent and CaSR-independent protein sensing regulates feeding and glucose tolerance in rats.

Proteins activate small intestinal calcium sensing receptor (CaSR) and/or peptide transporter 1 (PepT1) to increase hormone secretion1-8, but the effect of small intestinal protein sensing and the mechanistic potential of CaSR and/or PepT1 in feeding and glucose regulation remain inconclusive. Here we show that, in male rats, CaSR in the upper small intestine is required for casein infusion to increase glucose tolerance and GLP1 and GIP secretion, which was also dependent on PepT1 (ref. 9). PepT1, but not CaSR, is required for casein infusion to lower feeding. Upper small intestine casein sensing fails to regulate feeding, but not glucose tolerance, in high-fat-fed rats with decreased PepT1 but increased CaSR expression. In the ileum, a CaSR-dependent but PepT1-independent pathway is required for casein infusion to lower feeding and increase glucose tolerance in chow-fed rats, in parallel with increased PYY and GLP1 release, respectively. High fat decreases ileal CaSR expression and disrupts casein sensing on feeding but not on glucose control, suggesting an ileal CaSR-independent, glucose-regulatory pathway. In summary, we discover small intestinal CaSR- and PepT1-dependent and -independent protein sensing mechanisms that regulate gut hormone release, feeding and glucose tolerance. Our findings highlight the potential of targeting small intestinal CaSR and/or PepT1 to regulate feeding and glucose tolerance.

Recent Research on Mechanisms of Feeding Regulation in Chicks.

Food intake affects poultry productivity. A complete understanding of these regulatory mechanisms provides new strategies to improve productivity. Food intake is regulated by complex mechanisms involving many factors, including the central nervous system, gastrointestinal tract, hormones, and nutrients. Although several studies have been conducted to elucidate regulatory mechanisms in chickens, the mechanisms remain unclear. To update the current knowledge on feeding regulation in chickens, this review focuses on recent findings that have not been summarized in previous reviews, including spexins, adipokines, neurosecretory proteins GL and GM, and central intracellular signaling factors.

The role of pituitary adenylate cyclase-activating polypeptide neurons in the hypothalamic ventromedial nucleus and the cognate PAC1 receptor in the regulation of hedonic feeding.

Obesity is a health malady that affects mental, physical, and social health. Pathology includes chronic imbalance between energy intake and expenditure, likely facilitated by dysregulation of the mesolimbic dopamine (DA) pathway. We explored the role of pituitary adenylate cyclase-activating polypeptide (PACAP) neurons in the hypothalamic ventromedial nucleus (VMN) and the PACAP-selective (PAC1) receptor in regulating hedonic feeding. We hypothesized that VMN PACAP neurons would inhibit reward-encoding mesolimbic (A10) dopamine neurons via PAC1 receptor activation and thereby suppress impulsive consumption brought on by intermittent exposure to highly palatable food. Visualized whole-cell patch clamp recordings coupled with in vivo behavioral experiments were utilized in wildtype, PACAP-cre, TH-cre, and TH-cre/PAC1 receptor-floxed mice. We found that bath application of PACAP directly inhibited preidentified A10 dopamine neurons in the ventral tegmental area (VTA) from TH-cre mice. This inhibitory action was abrogated by the selective knockdown of the PAC1 receptor in A10 dopamine neurons. PACAP delivered directly into the VTA decreases binge feeding accompanied by reduced meal size and duration in TH-cre mice. These effects are negated by PAC1 receptor knockdown in A10 dopamine neurons. Additionally, apoptotic ablation of VMN PACAP neurons increased binge consumption in both lean and obese, male and female PACAP-cre mice relative to wildtype controls. These findings demonstrate that VMN PACAP neurons blunt impulsive, binge feeding behavior by activating PAC1 receptors to inhibit A10 dopamine neurons. As such, they impart impactful insight into potential treatment strategies for conditions such as obesity and food addiction.

Endogenous Opioids in the Homeostatic Regulation of Hunger, Satiety, and Hedonic Eating: Neurobiological Foundations.

This chapter (part one of a trilogy) summarizes the neurobiological foundations of endogenous opioids in the regulation of energy balance and eating behavior, dysregulation of which translates to maladaptive dietary responses in individuals with obesity and eating disorders, including anorexia, bulimia, and binge eating disorder. Knowledge of these neurobiological foundations is vital to researchers' and clinicians' understanding of pathophysiology as well as the science-based development of multidisciplinary diagnoses and treatments for obesity and eating disorders. We highlight mechanisms of endogenous opioids in both homeostatic and hedonic feeding behavior, review research on the dysregulation of food reward that plays a role in a wide array of obesity and disordered eating, and the clinical implications of neurobiological responses to food for current science-based treatments for obesity and eating disorders.

Streptococcus salivarius subsp. thermophilus CCFM1312 enhanced mice resilience to activity-based anorexia.

Probiotic intervention, already showing promise in the treatment of various psychiatric disorders like depression, emerges as a potential therapy for anorexia nervosa (AN) with minimal side effects. In this study, we established an activity-based anorexia (ABA) model to probe the pathogenesis of AN and assess the impact of probiotics on ABA mice. ABA resulted in a compensatory increase in duodenal ghrelin levels, impairing the regulation of feeding and the brain reward system. Intervention with Streptococcus salivarius subsp. thermophilus CCFM1312 ameliorated these ABA-induced effects, and the activation of neurons in the nucleus tractus solitarius (NTS) was observed following probiotic administration, revealing the advantageous role of probiotics in AN through the vagus nerve. Furthermore, our metabolomics analysis of cecal contents unveiled that S. salivarius subsp. thermophilus CCFM1312 modulated gut microbiota metabolism and thereby regulated intestinal ghrelin levels.

Neuropeptide Y: an undisputed central simulator of avian appetite

During the last few decades, identifying the physiological pathways involved in appetite regulation has become popular among researchers. Although studying feeding regulation in birds, especially in poultries (for breeding purposes) and ornamental birds (for therapeutic purposes), is extremely important, limited experiments have been conducted on these animal models. Until today, more than fifty neurotransmitters affecting birds' appetite have been identified. In the current study, we overviewed the role of one of the most important neural mediators, neuropeptide Y (NPY), in regulating avian appetite. Based on the findings, the presence of this neuropeptide and its receptors in the key areas of food intake regulation, especially the arcuate nucleus (ARC) of the hypothalamus, has been proven. Numerous studies on birds have repeatedly shown the hyperphagic effects of NPY. Among the different NPY receptors, type 1, 2 and 5 receptors play the most important role in appetite regulation. It has also been observed that the interaction of NPY with neurotransmitters such as glucagon-like peptide-1 (GLP-1), vasotocin, bombesin, opioids, alpha-melanocyte-stimulating hormone (α-MSH), cocaine- and amphetamine-regulated transcript (CART) and gamma aminobutyric acid (GABA) is effective in NPY-induced hyperphagia. In addition, the NPY system is also involved in the effects of various mediators such as adiponectin, neuropeptide W (NPW), phoenixin-14, visfatin, adrenomedullin, spexin, kisspeptin, insulin, and somatostatin on appetite regulation. Finally, NPY seems to be one of the most important appetite-stimulating factors in birds and also plays an undeniable role in the effects of other neurotransmitters on appetite regulation.

The effect of brain-derived neurotrophic factor (BDNF) on food consumption of broilers: Role of serotonergic receptors

Previously, the effects of brain-derived neurotrophic factor (BDNF) on feed intake of mammals were studied, however, its role in avian feeding regulation remains unclear. Therefore, the present study aimed to investigate the possible effects of BDNF on the food consumption of broilers and its interaction with the serotonergic system. In the first treatment, broilers received intracerebroventricular (ICV) infusion of BDNF (7.5, 15, and 30 μg). BDNF (30 μg), Fluoxetine (10 μg), a serotonin reuptake inhibitor, and BDNF + Fluoxetine were injected in the second treatment. In subsequent treatments, instead of Fluoxetine, PCPA (serotonin synthesis inhibitor, 1.25 μg), SB242084 (antagonist of 5-HT2C receptor, 1.5 µg), and 8-OH-DPAT (agonist of 5-HT1A receptor, 15.25 nmol) were applied. Then, total food intake was recorded for 2 hours. According to the results, BDNF injection (15 and 30 μg) caused a significant decrease in the food intake of broilers compared to the control group (P<0.05). Simultaneous administration of PCPA and SB242084 with BDNF suppressed BDNF-induced hypophagia (P<0.05), while the injection of fluoxetine + BDNF strengthened this hypophagic effect (P<0.05). The decrease in feed intake caused by BDNF was not significantly changed by simultaneous injection of BDNF + 8-OH-DPAT (P≥0.05). According to the findings, it seems that BDNF reduces food consumption in broilers and this effect is probably mediated via 5-HT2c receptors.

반려동물 사료 표시제도의 법률적 쟁점과 과제

Driven by the increasing number of pets and households that have pets, the pet food market is undergoing substantial growth. With the surge in pet guardianship, pet food consumption has increased, which has been accompanied by a growing interest in various functional pet food types. Despite the variety available, a notable issue exists concerning the primary labeling of pet food. This study investigates the current status and major issues within the pet food labeling system and proposes improvements.
 The labeling system for pet food is governed by the Control of Livestock and Fish Feed Act in conjunction with livestock feed regulations. This dual oversight presents challenges in providing precise information to pet food consumers through the labeling system. Currently, there are no established standards for differentiating pet food product names, specifying recommended feeding amounts, highlighting nutritional functions, or verifying pet food labeling. Additionally, a robust review system and review board dedicated to overseeing pet food labeling are absent.
 To foster the growth of the pet food industry, a revision of the current pet food labeling system is imperative. The proposed revision involves the following: First, reorganizing the classification system. The existing feed classification system of formulated feed and straight feed (mixed straight feed) should transition to a labeling classification system based on the intended purpose of the feed. Second, there is a need to regulate the contents of pet food, including product names and nutritional ingredients. Mandatory display of product names and the regulation of their use are essential components of this revision. Third, empirical standards and the establishment of a review advisory board to authenticate pet food labeling are needed. Regulations on the contents and procedures for labeling and advertising on efficacy and effectiveness should be established, grounded in a minimum scientific evidence threshold. Furthermore, there have been calls for the formation of an advisory or review committee composed of experts, which underscores the need for the establishment of a system to facilitate this.

Dynamic modelling of cross-flow printed circuit heat exchangers for multistage reactor intercooling

A reduced-order dynamic model of a cross-flow printed circuit heat exchanger was developed to study both steady-state and transient performance under conditions that would be encountered in multistage catalytic combustion reactors to better understand how they can be used to minimize fluctuations in heat-integrated reactors and intensified processes. Previous transient models for cross-flow heat exchangers rely on an initial steady state and apply only for changes in inlet temperature, but this work presents a model that can be applied to intermediate states or multiple concurrent upstream process changes. Steady-state simulations showed that larger channels reduce volumetric heat transfer performance and effectiveness due to convective resistance. Furthermore, larger channel spacing increases effectiveness but also reduces compactness. Operating temperature was found to have a minimal effect on the overall heat transfer coefficient and effectiveness within the range of conditions studied, and operating pressure was found to have no effect on heat transfer. Transient analyses showed that the response to a unit step in temperature matches closely with an analytical infinite gas velocity model, both for time constants and the overall thermal response, with initial variations in outlet temperatures from ideal-case models below 3.8 % of unit step magnitudes, and average differences below 0.75 %. Transient analyses also show the effects of a finite fluid velocity which is critical in the transient response of large heat exchangers. The presented numerical model can also be more easily extended to complex configurations and can be applied to other changes in inlet conditions such as changing composition and flow rates as are found in combustion applications. A three-fluid thermal management system for a multistage packed-bed microreactor using printed circuit heat exchangers is proposed and modelled to provide a method for temperature regulation and pre-heating of fresh reactor feed.

A Commercial Clay-Based Material as a Carrier for Targeted Lysozyme Delivery in Animal Feed.

The controlled supply of bioactive molecules is a subject of debate in animal nutrition. The release of bioactive molecules in the target organ, in this case the intestine, results in improved feed, as well as having a lower environmental impact. However, the degradation of bioactive molecules' in transit in the gastrointestinal passage is still an unresolved issue. This paper discusses the feasibility of a simple and cost-effective procedure to bypass the degradation problem. A solid/liquid adsorption procedure was applied, and the operating parameters (pH, reaction time, and LY initial concentration) were studied. Lysozyme is used in this work as a representative bioactive molecule, while Adsorbo®, a commercial mixture of clay minerals and zeolites which meets current feed regulations, is used as the carrier. A maximum LY loading of 32 mgLY/gAD (LY(32)-AD) was obtained, with fixing pH in the range 7.5-8, initial LY content at 37.5 mgLY/gAD, and reaction time at 30 min. A full characterisation of the hybrid organoclay highlighted that LY molecules were homogeneously spread on the carrier's surface, where the LY-carrier interaction was mainly due to charge interaction. Preliminary release tests performed on the LY(32)-AD synthesised sample showed a higher releasing capacity, raising the pH from 3 to 7. In addition, a preliminary Trolox equivalent antioxidant capacity (TEAC) assay showed an antioxidant capacity for the LY of 1.47 ± 0.18 µmol TroloxEq/g with an inhibition percentage of 33.20 ± 3.94%.

Neuropeptide Y receptor Y2 (npy2r) deficiency reduces anxiety and increases food intake in Japanese medaka (Oryzias latipes).

Neuropeptide Y receptor Y2 (npy2r) is an important receptor gene involved in anxiety and feeding regulation in mammals. Since NPY receptors have different receptor gene deletions in mammals and teleost fish, it is not clear whether npy2r has the similar function in fish as in mammals. In this study, we used the CRISPR/Cas9 system to establish npy2r-deficient medaka (Oryzias latipes). Unexpectedly, the deletion of npy2r resulted in the npy2r +/- medaka were all-male, therefore, npy2r homozygous mutant lines could not be established. The deletion of npy2r increased the food intake in medaka, and the expression levels of appetite stimulating genes (agrp, npy) increased significantly, while the expression levels of anorexia factors (cck, pomc) decreased significantly. Moreover, the absence of npy2r significantly increased the total length and body weight of medaka. The mirror test and open field test showed that npy2r +/- medaka improved sociability and reduced anxiety-like behavior, qRT-PCR analysis showed that the expression levels of anxiety related genes (th1, th2, gr1, gr2, and mr) in npy2r +/- medaka were significantly decreased. So far, this is the first npy2r gene knockout model established in fish and demonstrates that npy2r plays an important role in the regulation of reproduction, feeding and anxiety in fish.

230 Opportunities for and Threats Against Animal Production in the Commonwealth of Pennsylvania: the Need for Animal Scientists to Have a Role in Informing Society

Abstract Animal agriculture is critical to the economy and livelihoods in the Commonwealth of Pennsylvania. Animal agriculture is directly impacted by feed production, weather, disease pressure, regulations, and trade. Few of these, if any, are easily predictable. Thus, thirty-five diverse stakeholders across the supply chain, including feed mills, producers, veterinarians, animal scientists, and policymakers, came together with twenty undergraduate students to scan how factors like political, economic, social, and technological issues impacted the current and future state of animal production in the Commonwealth. Stakeholders were grouped by sector resulting in seven groups (e.g., production, feed processors, meat processors, animal health, conservation, policy, and finance). Session One asked participants to answer, ‘How will the changing outside world affect animal agriculture in the Commonwealth?’ While Session Two asked participants to answer, ‘Does the Commonwealth have the people, practices, equipment, etc. to fight threats and seize opportunities?’ All groups reported their discussions of opportunities and threats. These points were captured and then coded by issue type (e.g., political or social). Across all groups (i.e., 100% of groups), the lack of agriculture literacy in the consumer base was identified as a major threat to animal production in the Commonwealth. Three of seven groups (43%) recognized the political and financial momentum for climate-smart agricultural research and practices as an opportunity for academia, industry, and farmer partnerships. Additionally, three of seven groups (43%) saw increasing markets and decreasing costs of alternative, cultured proteins as a threat to animal production. Groups were split on whether new agriculture technologies were an opportunity or a threat. Some saw new technologies as a threat given the aging farmer population in the Commonwealth, while others saw new technology as an opportunity for better resource use and combating labor shortages. Albeit being state-specific, when taken together these findings provide insight into national-level trends in opportunities and threats that the animal sciences can help to seize and combat. These findings highlight the importance of animal science exiting the benchtop, the farm, and the classroom to better engage consumers and decision-makers seeking information about animal agriculture.

Mechanism of foraging selections regulated by gustatory receptor 43a in Ostrinia furnacalis larvae.

Omnivores, including humans, have an inborn tendency to avoid risky or non-nutritious foods. However, relatively little is known about how animals perceive and discriminate nutritious foods from risky substances. In this study, we explored the mechanism of feeding selection in Ostrinia furnacalis larvae, one of the most destructive pests to the maize crop. We identified a gustatory receptor, Gr43a, for feeding regulation in larvae of Ostrinia furnacalis, which highly expresses in the mouthparts of the first- (the period of just hatching out from eggs) and fifth-instar larvae (the period of gluttony). The Gr43a regulates foraging plasticity by discriminating sorbitol, a nonsweet nutritious substance, and sucralose, a sweet non-nutritious substance through the labra of mouthparts, while it differentiates fructose/sucrose and sucralose via the sensilla styloconica of mouthparts. Specially, Gr43a responds to fructose and sucrose via the medial and lateral sensilla styloconica in O. furnacalis, respectively. Furthermore, Gr43a is negatively regulated by the neuropeptide F system, a homologous mammalian neuropeptide Y system. This study reveals a smart feeding strategy for animals to meet both nutritional needs and sweet gratification, and offers an insight into complex feeding selections dependent on food resources in the surrounding environment. © 2023 Society of Chemical Industry.

Goldfish adiponectin: (I) molecular cloning, tissue distribution, recombinant protein expression, and novel function as a satiety factor in fish model.

Adiponectin (AdipoQ) is an adipokine involved in glucose homeostasis and lipid metabolism. In mammals, its role in appetite control is highly controversial. To shed light on the comparative aspects of AdipoQ in lower vertebrates, goldfish was used as a model to study feeding regulation by AdipoQ in fish species. As a first step, goldfish AdipoQ was cloned and found to be ubiquitously expressed at the tissue level. Using sequence alignment, protein modeling, phylogenetic analysis and comparative synteny, goldfish AdipoQ was shown to be evolutionarily related to its fish counterparts and structurally comparable with AdipoQ in higher vertebrates. In our study, recombinant goldfish AdipoQ was expressed in E. coli, purified by IMAC, and confirmed to be bioactive via activation of AdipoQ receptors expressed in HepG2 cells. Feeding in goldfish revealed that plasma levels of AdipoQ and its transcript expression in the liver and brain areas involved in appetite control including the telencephalon, optic tectum, and hypothalamus could be elevated by food intake. In parallel studies, IP and ICV injection of recombinant goldfish AdipoQ in goldfish was effective in reducing foraging behaviors and food consumption. Meanwhile, transcript expression of orexigenic factors (NPY, AgRP, orexin, and apelin) was suppressed with parallel rises in anorexigenic factors (POMC, CART, CCK, and MCH) in the telencephalon, optic tectum and/or hypothalamus. In these brain areas, transcript signals for leptin receptor were upregulated with concurrent drops in the NPY receptor and ghrelin receptors. In the experiment with IP injection of AdipoQ, transcript expression of leptin was also elevated with a parallel drop in ghrelin mRNA in the liver. These findings suggest that AdipoQ can act as a novel satiety factor in goldfish. In this case, AdipoQ signals (both central and peripheral) can be induced by feeding and act within the brain to inhibit feeding behaviors and food intake via differential regulation of orexigenic/anorexigenic factors and their receptors. The feeding inhibition observed may also involve the hepatic action of AdipoQ by modulation of feeding regulators expressed in the liver.

Age-related changes in the gut melatonin levels and its possible role in the regulation of feeding and digestibility, with the development of the gut from fingerling to adult stages of carp, Catla catla.

The present study aims to understand the feeding-related age-bound changes in gut histoarchitecture and its response to gut melatonin (GM) titer regulating major digestive enzymes in carp,Catla catla. Therefore, gut samples were collected from different growth stages of carp, viz. (i) fingerling (FL), body weight (BW) ≥ 3g to ≤ 20g; (ii) advanced fingerling (AFL), BW > 20g to ≤ 40g; (iii) early juvenile (EJv), BW > 40g to ≤ 70g; (iv) juvenile (Jv), BW > 70g to ≤ 200g; (v) late juvenile (LJv), BW > 200g to ≤ 300g; (vi) preadult (PA), BW > 300g to ≤ 500g; (vii) subadult (SA), BW > 500g to ≤ 1.00kg; and (viii) adult (AD), BW > 1kg to ≤ 2.5kg. Data analysis revealed that the highest titer of GM was noted in FL, moderate in AFL, Jv, and PA, lower in EJv, SA, and AD, and lowest in LJv. Results depicted a negative correlation between the development of the gut and its melatonin content. Moreover, GM was positively associated with feeding intensity and gastro-somatic index (GaSI) and negatively related to ovarian onset and development. Following correlation and principal component analysis, several pieces of evidence were recorded on the role of gut melatonin in regulating digestive physiology. Finally, it indicates that gut melatonin has a progressively influential role in improving digestion, particularly protein and microbial digestion, with the development of an adult gut from the fingerling stage.