Feed for hermetia illucens and breeding method of hermetia illucens rich in superoxide dismutase

Abstract

The invention belongs to the technical field of breeding, and particularly relates to feed for hermetia illucens and a breeding method of the hermetia illucens rich in superoxide dismutase. Preparing high-acidity fruit and vegetable residue slurry, and mixing the high-acidity fruit and vegetable residue slurry with a dry carrier to obtain a mixed material; adding a pH regulator into the mixed material to increase the pH; inoculating compound bacteria into the system, and fermenting to the end point thickness to obtain the feed; a food calling layer prepared from grain processing by-products is arranged, and hermetia illucens larvae are inoculated to the food calling layer; after the hermetia illucens larvae stably eat the feed, the feed is placed on the food calling layer to form a feed layer; after the hermetia illucens enters a rapid weight gain period before pre-pupa, high-acidity fruit and vegetable juice synergistic feed is added to the feed layer to serve as a strengthening layer. By means of the method, the palatability of the fruit and vegetable feed with the high acidity value is improved, and efficient cultivation of the functional hermetia illucens rich in SOD is achieved.

Description

Technical Field

[0001] This invention belongs to the field of aquaculture technology, specifically relating to a feed for black soldier flies and a method for raising black soldier flies rich in superoxide dismutase. Background Technology

[0002] Prickly pear, a specialty fruit of southwestern my country, is rich in vitamin C, flavonoids, and superoxide dismutase (SOD), among other active ingredients. During processing into juice and preserves, it produces pomace, which accounts for approximately 20% to 30% of the fresh fruit's weight. Currently, this pomace is mostly treated as waste. However, due to its high acidity and water content, prickly pear pomace is highly susceptible to decay and acidification, generating leachate that pollutes the environment, posing an environmental challenge to the development of the prickly pear industry. Meanwhile, black soldier flies, saprophagous insects, can efficiently convert organic waste such as kitchen waste, livestock manure, and fruit and vegetable scraps into high-protein insect feed and high-quality insect excrement organic fertilizer, representing an important pathway to achieving a circular economy in agriculture. For example, patent CN105433066A discloses a method for producing insect protein feed using black soldier flies to treat livestock manure. This method involves directly transferring black soldier fly larvae to a treatment tank containing livestock manure for manure disposal, ultimately obtaining insect protein feed.

[0003] Currently, there are three main types of technologies for using black soldier flies to treat fruit and vegetable waste: The first type is the direct mixed feeding method, which involves simply mixing apple pomace, grape pomace, vegetable waste, etc. with auxiliary materials such as bran and rice bran and then feeding them directly to the black soldier flies; the second type is the composting pretreatment method, which involves piling up fruit and vegetable waste for several days to allow it to ferment and decompose naturally before feeding it to the black soldier flies; and the third type is the dry matter compounding method, which involves drying and crushing fruit and vegetable waste and then compounding it with other protein sources and energy feeds before feeding it to the black soldier flies. However, directly applying these existing technologies to prickly pear residue has significant drawbacks: When directly mixed with feed, the high acidity of the prickly pear residue severely inhibits the digestive enzyme activity of black soldier fly larvae, leading to a larval rejection rate of over 80% and a mortality rate exceeding 50%. Composting pretreatment requires 5 to 7 days, which is not only time-consuming and prone to bacterial growth and foul odors, but also results in uncontrollable decay, significant loss of active ingredients, and unresolved issues of uneven fermentation leading to localized over-acidity. Dry matter compounding methods are energy-intensive and costly due to the high energy consumption of the drying process, and high-temperature drying destroys most of the active ingredients in the prickly pear residue, thus diminishing its potential value as a functional feed. Furthermore, existing technologies lack research on the enrichment of functional components in black soldier fly larvae. For example, patent CN110338271A discloses an insect protein source feed and its processing method, mainly focusing on maintaining the content of antimicrobial peptides through high-temperature sterilization and low-temperature drying, but does not address how to actively enrich specific functional components during the feeding process. Summary of the Invention

[0004] To address the problem in existing technologies where high-acidity fruit and vegetable residues (typically with a pH between 3.0 and 4.0), high fiber content, and high tannin content lead to high rates of feeding rejection, slow growth, and high mortality in black soldier fly larvae when fed untreated prickly pear residue, this invention provides a method for efficiently converting prickly pear residue into a feed suitable for black soldier fly larvae, enriching the larvae with active ingredients such as SOD, thereby obtaining functional black soldier fly feed and a method for raising them. The specific solution is as follows: A feed for black soldier fly larvae includes the following steps: a. Crush high-acidity fruit and vegetable residue to obtain high-acidity fruit and vegetable residue slurry; mix the high-acidity fruit and vegetable residue slurry with a dry carrier to obtain a mixture; add a pH adjuster to the mixture to adjust the pH to 6-7; b. The total number of viable bacteria inoculated into the system should not be less than 10. 8 The feed is a compound of lactic acid bacteria, yeast, and Bacillus subtilis, with a concentration of CFU / g. It is fermented until the pH stabilizes at 6.0 to 6.5, the texture becomes soft, and the color changes from yellow-green to yellow-brown.

[0005] Furthermore, the particle size of the components in the high-acidity fruit and vegetable residue slurry is no greater than 5 mm; the moisture content of the high-acidity fruit and vegetable residue slurry is 80-85%; the moisture content of the mixture is 60-65%; the amount of dry carrier added is 20-35% of the mass of the high-acidity fruit and vegetable residue slurry; and the fermentation is carried out at 28-32℃ for 24-36 hours.

[0006] Furthermore, the high-acidity fruit and vegetable residue includes one or more of the following: prickly pear residue, passion fruit residue, lemon residue, or sea buckthorn residue; the dry carrier includes wheat bran and leaf powder, which can regulate moisture and supplement nutrients; the grain processing by-product includes one or more of the following: wheat bran, corn flour, rice bran, or brewer's grains. The aforementioned leaf powder is rich in crude protein and has the functions of absorbing water and regulating the carbon-nitrogen ratio.

[0007] Furthermore, the leaf powder includes one or more of the following: paper mulberry leaf powder, mulberry leaf powder, or locust leaf powder; the mass ratio of the bran to the leaf powder is 2-3:1.

[0008] Furthermore, the pH adjuster is a dispersion of modified calcium carbonate-based biomass powder or a wood ash extract.

[0009] Furthermore, the mass concentration of the modified calcium carbonate-based biomass powder dispersion is 10-15%; the mass concentration of the wood ash extract is 5-10%.

[0010] Furthermore, the modification method of the calcium carbonate-based biomass includes the following steps: washing, drying, pulverizing, and passing the calcium carbonate-based biomass through an 80-100 mesh sieve, then calcining it at 400-600℃ for 1-3 hours; subsequently, dispersing the calcined product in an alkaline solution with pH 9-10 and stirring for 1-2 hours, using the alkaline solution for etching; filtering, washing, and drying to complete the modification. This process decomposes some of the calcium carbonate into calcium oxide and releases carbon dioxide, thereby forming a porous structure of micropores and mesopores within the particles, with a specific surface area reaching 50 to 100 m². 2 / g, with an average pore size between 5 and 50 nm; etching with alkaline solution can further enlarge the pores and form a connected structure.

[0011] Furthermore, the inoculation amount of the compound microbial agent is 0.5-1.5% of the mass of the mixed materials; the live count ratio of the lactic acid bacteria and Bacillus subtilis is 1-2:1; and the live count ratio of the yeast and Bacillus subtilis is 1-2:1.

[0012] A method for raising black soldier fly larvae rich in superoxide dismutase includes the following steps: setting up an attractant layer made from grain processing by-products, and introducing black soldier fly larvae onto the attractant layer; after the black soldier fly larvae have stabilized their feeding, placing the aforementioned feed on the attractant layer to form a feed layer; after the black soldier fly larvae enter the rapid weight gain period before pupation, adding feed with high acidity fruit and vegetable juice as an enhancement layer to the feed layer.

[0013] It typically takes 7-9 days for the larvae to grow to the prepupal stage. At this time, the larvae are plump and yellowish-brown, and they will automatically crawl out of the material to find a pupation site. The larvae are collected by an automatic separation device, and the frass is sieved out, thus obtaining functional black soldier fly larvae rich in SOD. Furthermore, the feed is placed on the feeding layer to form a 3-4 cm thick feed layer. After the feed is consumed and the feed sinks down, it is covered with a new 2-3 cm layer of feed. The total feed layer thickness is controlled to not exceed 12 cm. The thickness of the reinforcement layer is 2-3 cm.

[0014] Furthermore, the preparation method of the feed enhanced by high acidity fruit and vegetable juice includes the following steps: adding high acidity fruit and vegetable juice with a mass concentration of 10-15% to the feed; the amount of high acidity fruit and vegetable juice added is 5-20% of the feed mass.

[0015] By adopting the above scheme, the method of the present invention has the following advantages: 1. This invention solves the palatability problem of prickly pear residue through a three-step coupled process of conditioning-fermentation-gradient feeding. The larval refusal rate within 24 hours is significantly reduced, the survival rate is significantly increased, the breeding cycle is shorter, and a large amount of active substances are accumulated in the insect body, realizing the efficient cultivation of functional black soldier flies rich in SOD.

[0016] 2. This invention uses modified eggshell powder, seashell powder, or wood ash for pH adjustment. It utilizes the porous structure of these materials to adsorb excess moisture and acidic substances while slowly releasing alkaline components, thus avoiding the localized over-alkalinity that is prone to occur in conventional acid-base adjustments.

[0017] 3. Compared with the unmodified dense structure, the porous structure formed by the modified eggshell powder or shell powder of the present invention significantly increases the specific surface area and improves the contact efficiency with acidic materials. On the other hand, the alkaline components are loaded inside the pores and exhibit a gradient release characteristic when in contact with acidic substances, avoiding local over-alkaliness. The porous structure itself has a strong adsorption capacity, which can adsorb free acid and excess water in the prickly pear residue, further alleviating the stimulation of high acid materials on larvae.

[0018] 4. The fermentation process of this invention not only degrades some of the cellulose and tannins in the prickly pear residue, softening the material for easier larval feeding, but also generates organic acids and esters from lactic acid bacteria and yeast, creating chemical feeding signals that attract black soldier flies. Meanwhile, the proteases and cellulases secreted by Bacillus subtilis achieve "external pre-digestion" of the feed, significantly improving the subsequent digestion and absorption efficiency of the larvae. More importantly, the fermentation process releases and transforms bound SOD, flavonoids, and other antioxidants in the prickly pear residue, creating conditions for subsequent accumulation in the insects.

[0019] 5. In the gradient feeding process, this invention employs a three-dimensional gradient feeding strategy of attractant layer-main feed layer-reinforcement layer to reduce the black soldier fly's refusal rate. Furthermore, the reinforcement layer formed by the synergistic feed can induce the larvae to rapidly absorb and accumulate active ingredients such as SOD from the feed during the rapid weight gain period, enabling the larvae to achieve targeted enrichment of functional components in the later stages of growth.

[0020] 6. When the insects were raised using the method of the present invention, the SOD activity of the insects reached 1280 U / g (dry weight) and the flavonoid content reached 4.6 mg / g, which were 3.1 times and 2.6 times that of the natural composting group, respectively, and 2.9 times and 2.2 times that of the conventional fermentation group, respectively. This indicates that the method of the present invention can promote the production and enrichment of functional active substances.

[0021] 6. Using the method of this invention, it only takes 7 to 9 days from making pulp from prickly pear residue to harvesting insects. It does not require high-temperature drying, long-term natural composting, or complex environmental control equipment. The production cost is low and the equipment and operation threshold are low, making it suitable for large-scale production.

[0022] 7. The method of the present invention is not only applicable to prickly pear pomace, but can also be extended to the treatment of other high-acidity and high-activity fruit and vegetable pomace, such as passion fruit pomace, lemon pomace, and sea buckthorn pomace. Only the amount of pH adjuster and fermentation time need to be slightly adjusted according to the specific material characteristics. Detailed Implementation

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] Example 1: (1) Fresh prickly pear pomace was crushed in a crusher to a particle size of no more than 5 mm to obtain a homogeneous prickly pear pomace slurry. At this time, the moisture content of the prickly pear pomace slurry was 80-85%. Then, a composite dry carrier composed of wheat bran and paper mulberry leaf powder in a mass ratio of 2.5:1 was added to the prickly pear pomace slurry. The amount added was 30% of the mass of the prickly pear pomace slurry, and the moisture content was controlled to be 63% to obtain a mixture. Then, a modified oyster shell powder suspension with a mass concentration of 12% was sprayed evenly onto the mixture to adjust the pH value of the material to 6.5. (2) Add a compound fermentation agent, consisting of lactic acid bacteria, yeast, and Bacillus subtilis in a mass ratio of 1.5:1.5:1, to the conditioned material. The total number of viable bacteria in the agent shall not be less than 10. 8 The inoculation amount is 1% of the mass of the mixed feed. After inoculation, the material is piled into a 50cm high pile, covered with a breathable film, and fermented at 30℃ for 30 hours, turning the pile during the process to ensure uniform fermentation. The fermentation endpoint is reached when the material emits a strong sweet and sour wine aroma, the pH is stable at 6.0~6.5, the texture is soft, and the color changes from yellow-green to yellow-brown. The feed is then obtained. (3) First, lay a 2.5cm thick layer of pure bran at the bottom of the breeding tray as an attractant layer. Introduce 3rd instar black soldier fly larvae at a density of 6,000 per tray. Use the grain aroma of the bran to induce the larvae to quickly enter the feeding state. After the larvae have been feeding stably for 24 hours, evenly cover the attractant layer with the fermented feed. Use a small amount of feed multiple times. The first feed is 3cm thick. After the material is consumed and the temperature drops, cover it with a new 2cm layer of feed. Control the thickness of the feed layer to not exceed 12cm. (4) When the larvae enter the 5th instar, that is, the rapid weight gain period before pupation, feed them once with feed enhanced by spraying prickly pear juice as a reinforcement layer. The enhanced feed is made by uniformly spraying prickly pear juice with a mass content of 12% on the surface of the feed. The amount of prickly pear juice added is 8% of the feed mass.

[0025] Example 2: The difference from Example 1 is as follows: Replace the modified oyster shell powder suspension in step (1) with wood ash extract with a mass concentration of 8%.

[0026] Example 3: The difference from Example 1 is as follows: Enhanced feed is made by uniformly spraying 20% ​​prickly pear juice onto the surface of the feed.

[0027] Example 4: The difference from Example 1 is as follows: Replace the modified oyster shell powder suspension in step (1) with eggshell powder.

[0028] Example 5: The difference from Example 1 is as follows: In step (2), the pH-adjusted mixture is mixed with the feed at a mass ratio of 10:1 for natural inoculation and fermentation.

[0029] Example 6: The difference from Example 1 is as follows: Replace the pure bran in the feeding layer in step (3) with corn flour.

[0030] Example 7: The difference from Example 1 is as follows: Replace the pure bran in the feeding layer in step (3) with corn husks.

[0031] Example 8: The difference from Example 1 is as follows: Replace the pure bran in the feeding layer in step (3) with beer lees.

[0032] Comparative Example 1: The difference from Example 1 is that: The prickly pear residue and wheat bran were directly mixed at a mass ratio of 3:1 and then fed to the animals without conditioning or fermentation.

[0033] Comparative Example 2: The difference from Example 1 is that: Feed the prickly pear residue after it has been naturally composted for 5 days. Comparative Example 3: The difference from Example 1 is that: Mix prickly pear residue and wheat bran at a mass ratio of 3:1, add commercially available EM bacteria agent, ferment for 3 days, and then feed.

[0034] Comparative Example 4: The difference from Example 1 is that: No enhancement layer (i.e., only an appealing layer + main ingredient layer, without prickly pear juice for added effect).

[0035] Comparative Example 5: The difference from Example 1 is that: The reinforced layer contains 5% prickly pear juice.

[0036] Comparative Example 6: The difference from Example 1 is that: The reinforced layer contains 20% prickly pear juice.

[0037] Comparative Example 7: The difference from Example 1 is that: An equivalent amount of pure calcium carbonate was used to replace the modified oyster shell powder.

[0038] Comparative Example 8: The difference from Example 1 is that: An equivalent amount of pure potassium carbonate was used to replace the modified oyster shell powder.

[0039] Example Sample Testing: The growth of black soldier flies fed using the methods of Example 1, Comparative Examples 1 and 2 is shown in the table below. The feed conversion ratio was defined as the ratio of the weight of dry matter consumed to the weight of fresh larvae harvested, used to measure feed conversion efficiency.

[0040] Table 1: Growth of Black Soldier Flies

[0041] As shown in Table 1, when fed using the method described in the embodiments of the present invention, the 24-hour feeding refusal rate of larvae was only 5%, far lower than 85% in Comparative Example 1, 30% in Comparative Example 2, and 25% in Comparative Example 3. This indicates that the method of the present invention has strong appeal and excellent palatability for larvae, solving the core problem of larvae's refusal to eat prickly pear residue from the source. Regarding survival rate, the larval survival rate of Example 1 reached over 95%, significantly higher than 45% in Comparative Example 1, 72% in Comparative Example 2, and 78% in Comparative Example 3. This demonstrates that the present invention can significantly reduce the mortality rate of black soldier fly larvae, greatly improve the stability and success rate of breeding, and significantly reduce breeding risks. In terms of growth efficiency, the average breeding cycle of Example 1 was shortened to 7.2 days, and the feed conversion ratio was as low as 3.2, both superior to the comparative examples. This indicates that using the method of the present invention for feeding results in faster larval growth and higher feed conversion efficiency, shortening the production cycle, reducing raw material consumption, and improving the economic benefits of breeding. Regarding basic nutritional components, the crude protein content of the insect body in Example 1 reached 45.6%, which is higher than that of the comparative example (38.2% to 42.3%). This indicates that the method of the present invention is not only beneficial to the survival and growth of black soldier flies, but also significantly improves the nutritional value and commercial quality of black soldier flies.

[0042] The use of different pH adjusters during feed preparation directly affects the palatability of the feed. The specific results of black soldier fly consumption are shown in Table 2.

[0043] Table 2: Comparison of the effects of different pH adjusters:

[0044] As shown in Table 2, the feed treated with the modified calcium carbonate-based biomass powder dispersion or wood ash extract of this invention for pH adjustment exhibited significantly lower feed rejection rates and significantly higher black soldier fly survival rates. This indicates that the method of this invention can improve the pH stability of the material, resulting in smaller pH fluctuations and higher controllability during conditioning. It can prevent excessive alkalinity of the material and also avoid incomplete alkalization, thus fully ensuring the palatability of the feed.

[0045] The SOD activity in the insect body was detected using an SOD assay kit (hydroxylamine method), and the flavonoid content was detected using spectrophotometry (aluminum nitrate colorimetric method). The results are shown in Table 3.

[0046] Table 3: Comparison of SOD and flavonoid content in black soldier fly larvae

[0047] The SOD activity of the insects in this invention reached 1280 U / g, and the flavonoid content reached 4.6 mg / g, which were 3.1 times and 2.6 times that of Comparative Example 2, and 2.9 times and 2.2 times that of Comparative Example 3, respectively. This indicates that the present invention effectively solved the problem of refusal to eat caused by the high acidity and high tannins of prickly pear residue through conditioning and fermentation, significantly improved the digestion and absorption efficiency of prickly pear residue by black soldier flies, and successfully transferred and enriched the active ingredients such as SOD in the prickly pear residue into the insect body through gradient feeding and prickly pear juice fortification, thus obtaining a truly functional black soldier fly rich in SOD.

[0048] Meanwhile, the SOD and flavonoid contents of Comparative Example 4 without the reinforcement layer were twice that of Comparative Examples 1-3, indicating that the method of the present invention is beneficial to the enrichment of active substances in black soldier flies. However, the active substance content of Comparative Example 4 was only slightly more than half that of Example 1, and the active substance content of Comparative Example 5, with a prickly pear juice content of only 5%, also decreased significantly; indicating that the reinforcement layer of the present invention has a significant positive effect on the production of active substances in black soldier flies, and the setting of the reinforcement layer can directly affect the upper limit of the enrichment degree of active substances. At the same time, the SOD and flavonoid contents of Example 3, which used a prickly pear juice content as high as 20%, did not increase accordingly but decreased slightly, indicating that the setting of the reinforcement layer needs to be controlled within a suitable range. Too much or too little prickly pear juice to induce the enrichment of active substances will not achieve the best induction enrichment effect.

[0049] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this invention.

Claims

1. A feed for black soldier fly larvae, characterized in that, The method for preparing the feed includes the following steps: a. Crush high-acidity fruit and vegetable residue to obtain high-acidity fruit and vegetable residue slurry; mix the high-acidity fruit and vegetable residue slurry with a dry carrier to obtain a mixture; add a pH adjuster to the mixture to adjust the pH to 6-7; b. The total number of viable bacteria inoculated into the system should not be less than 10. 8 The feed is a compound of lactic acid bacteria, yeast, and Bacillus subtilis, with a concentration of CFU / g. It is fermented until the pH stabilizes at 6.0 to 6.5, the texture becomes soft, and the color changes from yellow-green to yellow-brown.

2. The black soldier fly feed according to claim 1, characterized in that, The particle size of the components in the high-acidity fruit and vegetable residue slurry is no greater than 5 mm; the moisture content of the high-acidity fruit and vegetable residue slurry is 80-85%; the moisture content of the mixture is 60-65%; the amount of dry carrier added is 20-35% of the mass of the high-acidity fruit and vegetable residue slurry; the fermentation is carried out at 28-32℃ for 24-36 hours.

3. The feed for black soldier fly larvae according to claim 1, characterized in that, The high-acidity fruit and vegetable residue includes one or more of the following: prickly pear residue, passion fruit residue, lemon residue, or sea buckthorn residue; the dry carrier includes wheat bran and leaf powder; and the grain processing by-product includes one or more of the following: wheat bran, corn flour, rice bran, or brewer's grains.

4. The black soldier fly feed according to claim 3, characterized in that, The leaf powder includes one or more of the following: paper mulberry leaf powder, mulberry leaf powder, or locust leaf powder; the mass ratio of the bran to the leaf powder is 2-3:

1.

5. The black soldier fly feed according to claim 1, characterized in that, The pH adjuster is a dispersion of modified calcium carbonate-based biomass or a wood ash extract.

6. The black soldier fly feed according to claim 5, characterized in that, The calcium carbonate-based biomass powder includes one or more of eggshell powder or seashell powder; the mass concentration of the dispersion of the modified calcium carbonate-based biomass powder is 10-15%; the mass concentration of the wood ash extract is 5-10%; the modification method of the calcium carbonate-based biomass includes the following steps: washing, drying, and pulverizing the calcium carbonate-based biomass and passing it through an 80-100 mesh sieve, calcining it at 400-600℃ for 1-3 hours; then dispersing the calcined product in an alkaline solution with pH 9-10 and stirring for 1-2 hours, etching it with alkaline solution; filtering, washing, and drying complete the modification.

7. The feed for black soldier fly larvae according to claim 1, characterized in that, The inoculation amount of the compound microbial agent is 0.5-1.5% of the mass of the mixed materials; the live count ratio of the lactic acid bacteria and Bacillus subtilis is 1-2:1; the live count ratio of the yeast and Bacillus subtilis is 1-2:

1.

8. A method for raising black soldier flies rich in superoxide dismutase, characterized in that, Includes the following steps: An attractant layer made from grain processing by-products is set up, and black soldier fly larvae are introduced onto the attractant layer. After the black soldier fly larvae have stabilized their feeding, the feed according to any one of claims 1 to 7 is placed on the attractant layer to form a feed layer. After the black soldier fly enters the rapid weight gain period before pupation, feed with high acidity fruit and vegetable juice is added to the feed layer as a reinforcement layer.

9. The method for raising black soldier flies rich in superoxide dismutase according to claim 8, characterized in that, The feed is placed on the feeding layer to form a 3-4 cm thick feed layer. After the feed is consumed and sinks, it is covered with a new 2-3 cm layer of feed. The total cumulative thickness of the feed layer is controlled to not exceed 12 cm. The thickness of the reinforcement layer is 2-3 cm.

10. The method for preparing black soldier fly larvae rich in superoxide dismutase according to claim 8, characterized in that, The preparation method of the feed enhanced by high acidity fruit and vegetable juice includes the following steps: adding high acidity fruit and vegetable juice with a mass concentration of 10-20% to the feed; the amount of high acidity fruit and vegetable juice added is 5-10% of the feed mass.

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