Appetite stimulant for abalone or sea urchin, neuropeptide Y synthesis promoter in abalone or sea urchin, and methods for producing them

Abstract

To provide a novel appetite enhancer for abalone and sea urchin derived from biomass.SOLUTION: Provided is an abalone or sea urchin appetite enhancer comprising g an extract derived from bagasse as an active ingredient.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an appetite stimulant for abalone or sea urchin, an agent for promoting neuropeptide Y synthesis in abalone or sea urchin, and methods for producing the same. [Background technology]

[0002] From the viewpoint of reducing the environmental load, the effective use of biomass has been attracting attention. As a method of utilizing biomass, its use as fuel such as bioethanol, its use in functional materials such as bioplastics, and its use as animal feed are being considered. For example, Patent Document 1 describes that by blending kraft pulp, a feed material that can promote rumination in ruminants can be obtained. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-201375 Summary of the Invention [Problem to be solved by the invention]

[0004] As disclosed in Patent Document 1, although the use of biomass as feed for livestock animals has been studied, the use of biomass as feed for aquatic organisms has not yet been fully studied. In addition, when providing feed to aquatic organisms, it is very important from the perspective of aquatic organism aquaculture to stimulate their appetite.

[0005] An object of one aspect of the present invention is to provide a novel appetite stimulant for abalone and sea urchin, which uses a component derived from biomass. [Means for solving the problem]

[0006] The present inventors have discovered that an extract derived from bagasse has the effect of promoting the synthesis of neuropeptide Y, which plays a role in promoting feeding behavior in abalone or sea urchin, and can be used to stimulate appetite, thereby completing the present invention.

[0007] That is, one aspect of the present invention provides an appetite stimulant for abalone or sea urchin, which contains an extract derived from bagasse as an active ingredient.

[0008] Another aspect of the present invention provides an agent for promoting neuropeptide Y synthesis in abalone or sea urchin, which comprises an extract derived from bagasse as an active ingredient.

[0009] The bagasse-derived extract is preferably a solid obtained by decomposing bagasse by at least one treatment selected from the group consisting of alkali treatment, hydrothermal treatment, acid treatment, and subcritical water treatment to obtain a decomposition treatment liquid, adjusting the pH of the decomposition treatment liquid to an acidic value, and then filtering the liquid.

[0010] Diatomaceous earth may be added to the digestion solution prior to filtration.

[0011] Yet another aspect of the present invention provides a method for producing an appetite stimulant for abalone or sea urchin, comprising the steps of decomposing bagasse by at least one treatment selected from the group consisting of alkali treatment, hydrothermal treatment, acid treatment, and subcritical water treatment to obtain a decomposition treatment liquid, adjusting the pH of the decomposition treatment liquid to an acidic value, and then filtering the liquid to obtain a solid.

[0012] Yet another aspect of the present invention provides a method for producing a promoter for neuropeptide Y synthesis in abalone or sea urchin, comprising the steps of decomposing bagasse by at least one treatment selected from the group consisting of alkali treatment, hydrothermal treatment, acid treatment, and subcritical water treatment to obtain a decomposition treatment liquid, adjusting the pH of the decomposition treatment liquid to an acidic value, and then filtering the liquid to obtain a solid. [Effects of the Invention]

[0013] According to one aspect of the present invention, a novel appetite stimulant for abalone and sea urchin, which uses a component derived from biomass, can be provided. [Brief explanation of the drawings]

[0014] [Figure 1] 10 is a graph showing the effect of an extract derived from bagasse on the expression level of neuropeptide Y mRNA in juvenile Hokkaido abalone, where (a) shows the results for juvenile oysters weighing 5.4 g, and (b) shows the results for juvenile oysters weighing 3.2 g. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0016] The appetite stimulant for abalone or sea urchin of the present invention has the effect of increasing the appetite of abalone or sea urchin (including juvenile shellfish or sea urchins). The appetite stimulant effect is mainly based on the effect of increasing the expression level of mRNA for synthesizing neuropeptide Y, which is present in cranial ganglia and plays a role in promoting feeding behavior. That is, another aspect of the present invention can be said to provide a neuropeptide Y synthesis promoter in abalone or sea urchin, which contains an extract derived from bagasse as an active ingredient. Alternatively, it can be said to provide an agent for enhancing the expression level of neuropeptide Y mRNA in abalone or sea urchin.

[0017] The type of abalone or sea urchin targeted for appetite stimulation in the present invention is not limited. For example, the abalone may be a shellfish belonging to the Haliotidae family, such as Ezo abalone, black abalone, Madaka abalone, or mega-i abalone. The sea urchin may be an echinoderm belonging to the class Echinoidea, such as the pulcherrimus, Ezo bafun sea urchin, northern purple sea urchin, red sea urchin, purple sea urchin, or pale-bearded sea urchin.

[0018] An appetite stimulant for abalone or sea urchin according to one embodiment contains an extract derived from bagasse as an active ingredient.

[0019] "Bagasse" refers to the residue left after sugarcane juice is extracted, typically the residue discharged during the sugar refining process in the raw sugar production process. A suitable bagasse is the bagasse discharged after the sugar juice is extracted in the extracting process at a raw sugar factory. The bagasse discharged during the sugar refining process at a raw sugar factory includes not only the final bagasse that leaves the final extractor, but also the shredded sugarcane that has been ingested by the first extractor or subsequent extractors. The moisture, sugar content, and their composition ratios contained in bagasse vary depending on the type of sugarcane, harvest time, etc., but any of these bagasse can be used in the present invention. Furthermore, in the present invention, the raw bagasse can also be bagasse remaining after sugarcane extraction in a brown sugar production factory, for example, or bagasse remaining after sugarcane juice is extracted from sugarcane in a small-scale laboratory experiment, just like in a raw sugar factory.

[0020] In one embodiment, the extract derived from bagasse (hereinafter also referred to as "bagasse extract") is a solid obtained by decomposing bagasse by at least one treatment selected from the group consisting of alkali treatment, hydrothermal treatment, acid treatment, and subcritical water treatment to obtain a decomposition treatment liquid, adjusting the pH of the decomposition treatment liquid to an acidic value, adding diatomaceous earth, and filtering the resulting liquid.

[0021] That is, to obtain a bagasse extract, bagasse is first decomposed by at least one treatment (decomposition treatment) selected from the group consisting of alkali treatment, hydrothermal treatment, acid treatment, and subcritical water treatment to obtain a decomposition treatment liquid.

[0022] The decomposition treatment of bagasse herein is required to destroy part or all of the chemical structures of lignin, cellulose, and / or hemicellulose. From the viewpoint of facilitating the production of a bagasse decomposition treatment liquid, the decomposition treatment is preferably an alkali treatment or a hydrothermal treatment.

[0023] The alkali treatment may be, for example, a treatment in which the bagasse is brought into contact with an alkaline solution. Examples of methods for bringing the bagasse into contact with the alkaline solution include a method in which the alkaline solution is sprinkled on the bagasse, and a method in which the bagasse is immersed in the alkaline solution. In the method in which the bagasse is immersed in the alkaline solution, the bagasse may be immersed while stirring a mixture of the bagasse and the alkaline solution.

[0024] Examples of the alkaline solution include an aqueous sodium hydroxide solution, an aqueous potassium hydroxide solution, and an aqueous ammonia solution. The alkaline solution may be one of these solutions alone or a mixture of two or more of them. From the viewpoints of being inexpensive and easily usable in food production processes, the alkaline solution is preferably an aqueous sodium hydroxide solution.

[0025] The concentration of the alkaline solution may be appropriately set depending on the type of alkaline solution used, but from the viewpoint of shortening the treatment time of the decomposition treatment, it is preferably 0.1% by mass or more, more preferably 0.2% by mass or more, and even more preferably 0.3% by mass or more. From the viewpoint of improving extraction efficiency, the concentration of the alkaline solution is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 1.0% by mass or less.

[0026] The alkaline solution is preferably heated. The temperature (liquid temperature) of the alkaline solution during alkaline treatment is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 80°C or higher, from the viewpoint of shortening the treatment time for the decomposition treatment. The temperature of the alkaline solution is preferably 110°C or lower, more preferably 105°C or lower, and even more preferably 100°C or lower, from the viewpoint of preventing polysaccharides from remaining in the decomposition treatment liquid.

[0027] The amount of alkaline solution added may be 50 parts by mass or more, 100 parts by mass or more, or 1,000 parts by mass or more relative to 100 parts by mass of bagasse. The treatment time for the alkaline treatment may be adjusted appropriately depending on the type, temperature, and amount of alkaline solution added, and may be, for example, 1 to 5 hours.

[0028] The alkali treatment may be carried out under normal pressure or under pressure. When pressure is applied, the pressure may be 0.1 MPa or more, or 0.2 MPa or more, and may be 4.0 MPa or less, 1.6 MPa or less, or 0.5 MPa or less.

[0029] The pH of the decomposition treatment liquid after the alkali treatment may be 8 or more, or 9 or more, and may be 13 or less, or 12 or less.

[0030] The hydrothermal treatment may be a treatment in which bagasse is brought into contact with high-temperature water or steam under high pressure. More specifically, the hydrothermal treatment may be a method in which water is added so that the solids concentration of the bagasse is 0.1 to 50%, and decomposition treatment is carried out under high-temperature and high-pressure conditions. The temperature of the water or steam is preferably 130 to 250°C, and the pressure applied is preferably 0.1 to 0.5 MPa higher than the saturated steam pressure of water at each temperature.

[0031] The acid treatment may be a treatment in which bagasse is brought into contact with an acidic solution. Examples of the acidic solution include dilute sulfuric acid and dilute hydrochloric acid. The acid treatment method may be a method in which the alkaline solution in the above-mentioned alkaline treatment is replaced with an acidic solution. That is, the method of bringing the bagasse into contact with the acidic solution, the temperature of the acidic solution in the acid treatment, the pressure conditions in the acid treatment, etc. may be the same as the method or conditions in the above-mentioned alkaline treatment.

[0032] The subcritical water treatment may be a treatment in which subcritical water is brought into contact with bagasse. The method of bringing subcritical water into contact with bagasse may be a method in which the alkaline solution in the above-mentioned alkaline treatment is replaced with subcritical water. The conditions for the subcritical water treatment are not particularly limited, but it is preferable that the temperature of the subcritical water is 160 to 240°C and the treatment time is 1 to 90 minutes.

[0033] The explosion treatment may be a treatment in which the insoluble xylan contained in the bagasse is decomposed to a certain extent by the above-mentioned hydrothermal treatment, and then the bagasse is pulverized by instantly releasing it to atmospheric pressure, for example, by suddenly opening a valve provided in a pressure-resistant reaction vessel.

[0034] After obtaining the bagasse decomposition liquid by the above-mentioned decomposition treatment, the decomposition liquid may be subjected to solid-liquid separation in order to remove insoluble components such as fiber. In this case, the liquid obtained after the separation operation can be used as the bagasse decomposition liquid. Solid-liquid separation may be performed by methods such as filtration using a strainer or filter, centrifugation, decantation, etc.

[0035] From the decomposition treatment liquid, high molecular weight components such as polysaccharides may be removed by membrane separation. In this case, the liquid after membrane separation can be used as the decomposition treatment liquid. The separation membrane is not particularly limited as long as it is an ultrafiltration membrane (UF membrane). The molecular weight cutoff of the ultrafiltration membrane is preferably 2500 to 50,000, more preferably 2500 to 5,000.

[0036] Materials that can be used for the ultrafiltration membrane include polyimide, polyethersulfone (PES), polysulfone (PS), polyacrylonitrile (PAN), polyvinylidene fluoride (PVDF), regenerated cellulose, cellulose, cellulose ester, sulfonated polysulfone, sulfonated polyethersulfone, polyolefin, polyvinyl alcohol, polymethyl methacrylate, and polytetrafluoroethylene.

[0037] The filtration method using an ultrafiltration membrane may be dead-end filtration or cross-flow filtration, but from the viewpoint of suppressing membrane fouling, cross-flow filtration is preferred.

[0038] The ultrafiltration membrane may be of any suitable form, such as a flat membrane, spiral wound type, tubular type, hollow fiber type, etc. More specifically, examples include the GE series, GH series, GK series, PW type, and HWSUF type from SUEZ, HFM-180, HFM-183, HFM-251, HFM-300, HFK-131, HFK-328, MPT-U20, MPS-U20P, and MPS-U20S from KOCH, SPE1, SPE3, SPE5, SPE10, SPE30, SPV5, SPV50, and SOW30 from Synder, those equivalent to the molecular weight cutoff of 3,000 to 10,000 in the Microza (registered trademark) UF series manufactured by Asahi Kasei Corporation, and NTR7410 and NTR7450 manufactured by Nitto Denko Corporation.

[0039] Subsequently, the pH of the resulting decomposition solution is adjusted to an acidic state, whereby part or all of the active ingredient of the appetite stimulant of the present invention is precipitated as a solid content.

[0040] The pH of the decomposition treatment liquid can be adjusted to an acidic state by, for example, adding an acidic solution to the decomposition treatment liquid. From the viewpoint of applicability in the food industry, hydrochloric acid is preferably used as the acidic solution. The concentration of hydrochloric acid may be appropriately set within a range in which the pH can be adjusted, for example, 0.1 to 35% by mass.

[0041] The pH of the decomposition treatment liquid after pH adjustment (hereinafter also referred to as "acid treatment liquid") is preferably 4.5 or less, more preferably 4.0 or less, and even more preferably 3.5 or less, from the viewpoint of easily obtaining components that stimulate the appetite of abalone or sea urchin. From the same viewpoint, the pH of the acid treatment liquid is preferably 1.5 or more, more preferably 2.0 or more, and even more preferably 2.5 or more.

[0042] The acid-treated solution is then filtered. The filtration separates the solid matter precipitated in the acid-treated solution from the liquid matter other than the solid matter, yielding a solid matter (residue). This solid matter can be used as a bagasse-derived extract, which has the effect of stimulating the appetite of abalone or sea urchin.

[0043] The acidic treatment liquid may be filtered by natural filtration, reduced pressure filtration, pressure filtration, centrifugal filtration, or the like, and is preferably filtered by pressure. Pressure filtration may be performed using a pressure filter (filter press). The filtration conditions can be appropriately adjusted within a range that allows the solid matter precipitated in the acidic treatment liquid to be captured.

[0044] Diatomaceous earth may be added to the acidic treatment solution before filtration. By adding diatomaceous earth, the components (solids) that have the effect of increasing the appetite of abalone or sea urchin are captured in the pores of the porous diatomaceous earth, making it easier to obtain a bagasse-derived extract. In this case, the bagasse-derived extract may be the solid matter itself after filtration. In other words, the bagasse-derived extract may contain the bagasse-derived components obtained by the above-mentioned treatment and diatomaceous earth.

[0045] The type or origin of diatomaceous earth that can be used is not particularly limited, and diatomaceous earth produced in various regions can be used as appropriate. Calcined diatomaceous earth can also be used. The form of diatomaceous earth is preferably powder or granular.

[0046] The physical properties or grade of the diatomaceous earth can be selected as appropriate. For example, the 50% average particle size (D50, measured by a laser method) is 10 to 80 μm, the transmittance based on the Darcy formula is 0.01 to 10 darcy, and the bulk density (cake bulk density) is 0.15 to 0.3 g / cm. 3 The diatomaceous earth may be selected appropriately from the range of 1 to 3. Commercially available diatomaceous earth may also be used.

[0047] The amount of diatomaceous earth added may be 0.2 mass% or more, 0.5 mass% or more, or 0.8 mass% or more, relative to the total amount of the acidic treatment solution and diatomaceous earth, and may be 2 mass% or less, 1.6 mass% or less, or 1.3 mass% or less.

[0048] The bagasse extract obtained by the above method may be subjected to a drying treatment such as natural drying or hot air drying, if necessary.

[0049] The appetite stimulant may consist solely of the active ingredient, a bagasse-derived extract, or may contain other ingredients that can be used as feed for abalone or sea urchin, such as carbohydrates such as wheat flour, seaweed such as sea lettuce, wakame seaweed, kelp, and green laver, fish-derived ingredients such as fish meal and fish oil, various vitamins, minerals such as calcium and phosphorus, and thickeners such as sodium alginate.

[0050] When the appetite stimulant contains other ingredients, the content of bagasse extract may be 0.005% by mass or more, 0.007% by mass or more, or 0.01% by mass or more, and may be 0.5% by mass or less, 0.1% by mass or less, or 0.05% by mass or less, based on the total amount of the appetite stimulant.

[0051] The shape of the appetite stimulant is not limited as long as it is a shape that can be ingested by abalone or sea urchin. The appetite stimulant may be in the form of a solid (powder, granules, etc.), a liquid (solution, suspension, etc.), a paste, a gel, etc. Alternatively, a liquid or paste may be gelled to form a bead-shaped gel bait.

[0052] The appetite stimulant can be ingested by abalone or sea urchin as food (oral administration). The amount of intake may be an amount that results in a daily intake of bagasse extract of 0.1 μg / g (body weight) or more, 0.5 μg / g (body weight) or more, or 1 μg / g (body weight) or more, and may be an amount that results in a daily intake of 50 μg / g (body weight) or less, 10 μg / g (body weight) or less, or 5 μg / g (body weight) or less. Ingestion of this amount can sufficiently stimulate the appetite of the abalone or sea urchin.

[0053] The appetite stimulant for abalone or sea urchin according to this embodiment can increase the appetite of abalone or sea urchin, and can therefore be used for promoting their growth, encouraging the excretion of toxins accumulated in their bodies, increasing valuable substances in the body to increase nutritional value, improving meat quality, taste, or flavor, brightening their appearance, activating their activity, promoting reproduction, improving the structure or strength of their shells or spines to make them easier for humans to handle, promoting regeneration to recover from damage caused by predation, etc. Regarding growth promotion, in aquatic organisms other than abalone and sea urchin (fish, crustaceans, etc.), the growth of aquatic organisms is promoted by increasing the amount of insulin-like growth factor I (IGF-I) synthesized in the liver, but this is unrelated to the appetite-stimulating effect of the present invention.

[0054] An appetite stimulant for abalone or sea urchin according to one embodiment, which contains an extract derived from bagasse as an active ingredient, can be obtained by the above-described production method. That is, the production method for an appetite stimulant for abalone or sea urchin according to one embodiment comprises the steps of decomposing bagasse by at least one treatment selected from the group consisting of alkali treatment, hydrothermal treatment, acid treatment, and subcritical water treatment to obtain a decomposition treatment liquid, adjusting the pH of the decomposition treatment liquid to an acidic value, and then filtering the liquid to obtain a solid. Specific aspects of each step are as described above.

[0055] Next, a neuropeptide Y synthesis promoter in abalone or sea urchin according to one embodiment will be described. Specific aspects of the neuropeptide Y synthesis promoter in abalone or sea urchin may be similar to those of the appetite stimulant for abalone or sea urchin described above. That is, the neuropeptide Y synthesis promoter in abalone or sea urchin according to one embodiment may be obtained by replacing "appetite stimulant for abalone or sea urchin" in the above description with "neuropeptide Y synthesis promoter in abalone or sea urchin." The same applies to a method for producing a neuropeptide Y synthesis promoter in abalone or sea urchin.

[0056] A neuropeptide Y synthesis promoter in abalone or sea urchin can increase the expression level of mRNA for synthesizing neuropeptide Y, which is present in the cerebral ganglia of abalone and sea urchin. As a result, neuropeptide Y synthesis is promoted in abalone or sea urchin. Neuropeptide Y is a peptide neurotransmitter that is mainly involved in regulating appetite. Increasing neuropeptide Y promotes appetite in abalone or sea urchin.

[0057] In addition to the effect of increasing appetite, neuropeptide Y also has effects such as regulating gastrointestinal function, regulating energy expenditure, sexual maturation, and regeneration. Therefore, according to one embodiment, a promoter for promoting neuropeptide Y synthesis in abalone or sea urchin can be used for increasing appetite, regulating gastrointestinal function, regulating energy expenditure, activating reproductive activity, and recovering from damage caused by predation, etc. [Example]

[0058] The present invention will be described in more detail below with reference to examples, although the present invention is not limited to the following examples.

[0059] <Production of bagasse-derived extract> 3.2 kg of bagasse (sugarcane pomace, moisture content 50% by mass) and 20 L of 0.5% (w / w) aqueous sodium hydroxide solution at 90°C were added to a stainless steel saucepan and mixed for 2 hours to carry out a decomposition treatment. The mixture after the decomposition treatment was separated into insoluble components (fiber, etc.) and a liquid fraction, yielding approximately 20 L of the liquid fraction. This separation procedure was repeated twice to obtain 40 L of the liquid fraction (decomposition treatment liquid).

[0060] To the total amount of this decomposition treatment liquid, 475 mL of 35% (w / w) hydrochloric acid was added to adjust the pH to 3.0. This was used as the acid treatment liquid. 395 g of diatomaceous earth (an amount equivalent to 1% by mass based on the total amount of the acid treatment liquid and diatomaceous earth) was added to the acid treatment liquid, and pressure filtration was performed using a filter press. After filtration, the solid matter containing diatomaceous earth that did not pass through the filter was collected. This was used as an extract derived from bagasse (bagasse extract).

[0061] <Feeding method> We used young Ezo abalone (weighing approximately 5.4 g) reared at the Marine Education and Research Center, attached to the Kitasato University School of Marine Life Sciences. Four plastic cages (30 x 40 x 25 cm) were placed in a 1-ton indoor aquarium, with 50 young abalone in each cage. A gel diet containing the bagasse extract was prepared. Specifically, the bagasse extract was mixed with wheat flour (55% by mass), seaweed powder (30% by mass), and crude sodium alginate extract (5% by mass) prepared from wakame stems (Wakame seaweed) at a final concentration of 0.01% or 0.05% by mass. The mixture was then added dropwise to a calcium chloride solution to form a gel. This gel diet was fed to abalone juveniles every two days at a dose of 2% by mass per gram of body weight for six months. Control groups included a group fed a similar amount of gel diet prepared without the bagasse extract (Control Group 1) and a group fed a similar amount of a commercially available formulated abalone juvenile feed (4N, Nosan Corporation) (Control Group 2). The same experiment was also conducted on young Ezo abalone weighing approximately 3.2 g. However, the feeding period was 5 months, and no control group 2 was used. Table 1 summarizes the test groups.

[0062] [Table 1]

[0063] <Evaluation of neuropeptide Y expression level> After the feeding period, abalone cranial ganglia were collected (n = 10) and stored in RNA later solution at 4°C until use. RNA was extracted from the cranial ganglia using the RNeasy Mini Kit (QIAGEN). Approximately 10 mg of cranial ganglia was placed in a 1.5 mL tube, and Buffer RLT (500 μL) and one zirconia bead (3 mm diameter) were added. The contents of the tube were disrupted using a cell disrupter (Micro Smash MS-100, Tomy Seiko Co., Ltd.) at 3,000 rpm for 10 seconds until all solids were removed. The tube was then centrifuged (16,700 × g, 3 minutes, 24°C), and the supernatant was transferred to a new 1.5 mL tube. An equal volume (500 μL) of 70% ethanol was added and mixed by pipetting. The mixture was added to an RNeasy spin column and centrifuged (7900 × g, 15 seconds, 24°C). Buffer RW1 (700 μL) was then added to the column, followed by centrifugation. Buffer RPE (500 μL) was then added and centrifuged again. The same volume of Buffer RPE was added again, and the column was washed by centrifugation (7900 × g, 2 minutes, 24°C). The column was placed in a new 1.5 mL tube, and RNeasy Free Water (20 μL) was added to the center of the column. After standing for 1 minute, total RNA was eluted by centrifugation (7900 × g, 1 minute, 24°C). The concentration of the resulting total RNA was calculated by measuring the absorbance at 260 nm and 280 nm using a spectrophotometer (NanoVue Plus, GE Healthcare). The column was stored at -80°C until use.

[0064] β-actin (βAN) was used as an internal standard. Primers for abalone neuropeptide Y (NPY) and βAN were designed based on the cDNA sequences using Primer3 web version 0.4.0 (http: / / bioinfo.ut.ee / primer3-0.4.0 / ). Semi-quantitative PCR for NPY was performed using the KAPA SYBER FAST One Step qRT-PCR Kit. Total RNA prepared from cranial ganglia (n=4) was serially diluted to 0.0098, 0.0391, 0.1563, 0.625, 2.5, and 10 ng as a standard sample. 2 μL of serially diluted total RNA was added to a well of a 96-well Hi-Plate for Real Time (Takara Bio Inc.), followed by 5.0 μL of KAPA SYBER FAST qPCR Master Mix, 0.2 μL of dUTP, 0.2 μL of KAPA RT Mix, 2.2 μL of sterile water, and 0.2 μL of forward and reverse primers. The concentrations of the NPY and βAN primers were 5.0 and 10 μM, respectively. The PCR reaction consisted of a reverse transcription reaction at 42°C for 5 minutes, followed by an enzyme activation reaction at 95°C for 10 minutes, followed by 40 cycles of thermal denaturation (95°C, 5 seconds) and annealing / extension (60°C, 30 seconds). The thermal real-time PCR device used was the Thermal Cycler Dice Real Time System (Takara Bio Inc.).

[0065] Figure 1(a) shows the NPY mRNA expression levels in the cranial ganglia of each test group, collected from 5.4g juvenile Hokkaido abalone oysters six months after the start of the test. Figure 1(b) shows the NPY mRNA expression levels in the cranial ganglia of each test group, collected from 3.2g juvenile Hokkaido abalone oysters six months after the start of the test. In both cases, the NPY mRNA expression levels in the cranial ganglia of treatment groups 1 and 2, which consumed gel feed containing bagasse extract, were significantly higher than that of control group 1 (treatment group 1: p<0.05, treatment group 2: p<0.01). This demonstrates that bagasse extract enhances the expression levels of NPY, which regulates abalone appetite.

Claims

1. A method for producing an appetite stimulant for abalone or sea urchin, comprising the steps of decomposing bagasse by at least one treatment selected from the group consisting of alkali treatment, hydrothermal treatment, acid treatment, and subcritical water treatment to obtain a decomposition treatment liquid, adjusting the pH of the decomposition treatment liquid to an acidic value, and then filtering the liquid to obtain a solid.

2. The method of claim 1 , wherein diatomaceous earth is added to the decomposition treatment liquid before the filtration.

3. A method for producing a promoter for neuropeptide Y synthesis in abalone or sea urchin, comprising the steps of decomposing bagasse by at least one treatment selected from the group consisting of alkali treatment, hydrothermal treatment, acid treatment, and subcritical water treatment to obtain a decomposition treatment liquid, adjusting the pH of the decomposition treatment liquid to an acidic value, and then filtering the liquid to obtain a solid.

4. The method of claim 3 , wherein diatomaceous earth is added to the decomposition treatment liquid before the filtration.

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