Synthesis and Characterization of Ruminant Feed Based on Palm Kernel Cake Using EM4 Fermentation Method

The purpose of this study was to determine the effect of the addition of cassava as an adhesive and the use of palm kernel meal as a concentrate and the addition of other ingredients on the physical, mechanical and chemical properties of food ingredients in the form of pellets. The animal feed was made by mixing palm kernel meal, tofu dregs, rice bran, and cassava with a percentage of (68,5 : 15,75 : 5,25 : 10,5)% and mixing molasses and EM 4 in a ration 1 : 1. The test samples were made by going through the stages of weighing, chopping, mixing, fermentation, drying, and molding into pellets. The results showed that the animal feed mixture had a specific gravity of 1.70 gr/mL, porosity of 29.05%, water absorption of 72.62%, pellet hardness of 4.85%, and brittleness with 4.92%. Animal feed pellets have a brownish color and a normal smell like the smell of animal feed pellets in general. The fermentation process was carried out for 8 days until it reached a maturity temperature of 38.44°C. Based on the proximate analysis, it was found that the animal feed contained 10.50% protein, 2.30% total fat, 22.80% crude fiber, 28.50% carbohydrate, 3.00% ash content and 32.90% moisture content. This animal feed pellet with palm kernel meal concentrate and cassava adhesive can be used as an alternative to cattle feed as an energy source feed, because it has a protein content of less than 20%.


Introduction
Feed is one of the main factors in the success of goat breeding.Especially during the dry season, the availability of grass and fodder for goats is very limited.Innovation of alternative food sources and alternative food processing is a solution to food availability every year, of course, by paying attention to energy and protein sources [1].Environmental pollution has increased significantly lately because of the many industrial activities in the world, especially in Indonesia which is of concern.Industrial waste pollutes the environment directly or indirectly [2].Ruminant feed always comes from plants with high fiber content.With the development of animal husbandry, farm animals need additional nutrients in the form of concentrate feed or concentrates, either in the form of protein, energy, or their combination [3].
Declining land availability and increasing livestock numbers make it difficult for farmers to access feed.This difficulty is even more pronounced when the rainy season or dry season arrives.In cattle IOP Publishing doi:10.1088/1755-1315/1352/1/012097 2 breeding, a semi-intensive method is still used, namely the H. livestock system, which is kept partly in pastures and partly in cages.This method is inseparable from the socio-economic conditions of farmers who find it difficult to meet the needs of animal feed in general [4].Agricultural and plantation wastes are utilized among others as a source of ruminant feed, because this feed does not compete with human needs.As in maize cultivation, husk is the main product in the form of corn husk, the by-products are corn stalks (corn stalks and leaves), husks and cobs.In some maize-growing areas, maize stover, especially cobs, is simply discarded or burned, although it can be reused as raw material for ruminants [5].Certain requirements are placed on livestock materials so that livestock productivity is not damaged.These requirements also apply to all types of domesticated animals, such as birds and ruminants.Some of these requirements are good nutritional content, constant availability, low price and no competition with humans [6].
The utilization of palm kernel cake as a local feed source has been widely done.Palm kernel cake is considered quite potential as feed because it has good nutrient content for livestock [7].Feed for dairy cows must contain energy and protein to meet the nutritional needs of dairy cows.The results of proximate analysis show that the nutritional value of palm kernel cake is 86.10% dry matter, 86.20% organic matter, 13.80% ash, 20.48% crude protein, 14.61% crude fat, and 19.52% crude fiber [8].In this study, researchers used palm kernel cake as concentrate with the addition of tofu pulp, bran, and cassava which functioned as an adhesive using the fermentation method with the addition of EM 4 and molasses.Sweet potatoes contain salt (solute) and water (solvent), which allows ions to move freely.This movement of ions generates electricity [9].The selection of palm kernel cake as feed raw material is due to the large amount of unused waste from palm oil processing and contains high protein.The characteristics of animal feed will be known by conducting several tests in the form of physical property tests, namely specific gravity, porosity, water absorption, water solubility, color, odor, and fermentation maturity temperature; mechanical property tests in the form of hardness and brittleness tests on animal feed pellets; and chemical property tests by conducting proximate analysis of protein content, total fat, crude fiber, carbohydrates, ash content, and moisture content of animal feed.

The process of making animal feed pellets,
Cassava is peeled, washed thoroughly with water and dried.After drying, the cassava is pulverized with a hammer mill with a diameter of 1-2 mm to produce cassava flour.Mixing molasses and EM4 in a ratio 1:1 with palm kernel meal, cassava flour, bran, and tofu dregs with a composition of 68.5%: 15.75% : 5.25% : 10.5% (obtain the composition by calculating the protein content of the ingredients so as to obtain a feed formulation that contains appropriate nutrients and is economically cheap and easy to obtain).All ingredients are thoroughly mixed and placed in a sealed container for fermentation.Fermentation is carried out for ± 14 days until the maturation temperature is reached in the range of 30 -40°C [10].After the fermentation process is complete, the animal feed is dried and then the pellet molding process is carried out.Pellet molding is done using a 3 mm diameter pellet molding machine.
The composition of the animal feed was prepared based on the Pearson Square Method, which is based on the division of protein content of ruminant feed ingredients, namely basal protein (feed ingredients with protein content < 20%) and supplement protein (feed ingredients with protein content > 20%).In this study, the composition of raw materials for making feed added additional ingredients in the form of 2% vitamin mix, and 2% minerals, so it had to reduce the amount of main raw materials by the amount of additional raw materials used to be 100% -2% vitamin mix -2% minerals = 96%.So, the amount of protein content that must be met is 35% x 100% / 96% = 36.46%.This is done because vitamins and minerals do not have protein content [11].

Characterization
This research characterizes the physical test, including specific gravity, porosity, water absorption, water solubility, color, and odor; mechanical test, including tests of hardness and brittleness of pellets; and proximate analysis, including tests of protein content, carbohydrates, crude fiber, total fat, moisture content, and ash content; and measurement of temperature during fermentation.

The specific gravity
Specific gravity of solids is a quantity that compares mass (m) to volume (v).specific gravity is expressed in g/cm 3 [12].The larger the diameter of the pellets, the smaller the cohesiveness of the material [13].The nature of biomass materials makes it possible to get unique porous properties that can be used to make electrode materials.Biomass carbons can be made with porous and interconnected structures [14].To calculate the amount of specific gravity.The equation is used in accordance with ASTM D792-20 [15].

Porosity
To get the porosity value, in solid samples, porosity is carried out using density calculations, since density is described as the amount of mass per unit volume, and porosity is measured as the ratio of pore volume to overall volume, porosity can be calculated using the concept of density.Due to its high specific gravity and porosity, feed will not float if it is not combined with other components.The porosity of a material can be calculated by equation 2 in accordance with ASTM C642-90.
= mass of the sample in wet state   = mass of the sample in a dry state   = density of distilled water   = sample volume

Water absorption
Water absorption measurement is the percentage ratio of the difference between wet and dry mass.The wet mass is then measured [16].Water absorption was obtained from measuring the weight of pellets before and after soaking in water for 5 minutes [17].By using the equation in accordance with ASTM D1762-84, the percentage of water absorption is [18].
= mass of the sample in wet state   = mass of the sample in dry state

Water solubility
The factor that affects total solubility is the type of carbohydrate component.The higher the content of non-starch polysaccharides in feed ingredients, the lower the solubility of feed ingredients in water, and vice versa.The higher the total solubility value in animal feed, reflecting the high digestibility [19].The test was conducted at Medan City Industrial Research and Standardization Center based on the SNI 01-2891-1992 test method.

Color and odor
The color of pelleted feed from various livestock tends to be light brown.This shows that a good color in animal feed in the form of pellets is pellets that have a bright brown color without spots.For a good pellet odor is an odor that resembles the raw material it is made from, smells fresh and not rancid [20].
The test was conducted at Medan City Industrial Research and Standardization Center based on the SNI 01-2891-1992 test method.

Fermentation temperature
Endothermic processes occur at temperatures below 100°C.This is due to the energy generated during thermal decomposition is the oxidation reaction in Sample [21].Temperature test parameters are carried out with the help of a DS18B20 temperature sensor which is controlled in the morning, afternoon, and evening for 8 days until it reaches a maturity temperature in the range of 30 -40°C.

Hardness
Based on ASTM E348-22, hardness tests have proven to be very useful for material evaluation, quality control of manufacturing processes, as well as research, and development efforts [22].Artificial feed should have physical characteristics that are compact and dry, so that when put into water, the feed becomes soft but not crushed [23].Good pellets have hardness values ranging from 3.92 to 6.37.Pellet size and ingredients affect animal feed hardness value.The composition of the feed ingredients, the adhesive used, and the conditioning process is factors that can affect hardness.Hardness testing is done using a hardness tester.

Brittleness
The friability test aims to ensure that the animal feed pellets have physical resistance to shocks during the distribution and storage process.The friability of pellets is related to the hardness of the pellets, this is because the higher the hardness of the pellets, the lower the friability.The friability of pellets can be influenced by the strength of the binder [24].The brittleness is also calculated using the following equation based on the American Society of Agricultural and Biological Engineers Standard S269.4.
= initial mass of the sample   = final mass of the sample 2.12.Proximate analysis Proximate analysis aims to determine the nutritional content of animal feed samples to be produced.The test was conducted at the Medan City Industrial Research and Standardization Center using a test method based on SNI 01-2891-1992.

Specific gravity
The results of measurements of the specific gravity of animal feed processed with Equation (1), get the results as listed in Table 1.
Table 1.The results of specific gravity with 5 repetitions.
Iteration to Mass (g) Volume (cm 3 ) Specific Gravity (g/cm From Table 1, it can be seen that the average value of specific gravity obtained from testing with 5 repetitions is 1.70 gr/cm 3 .The specific gravity value of animal feed can vary depending on the type of animal to be fed, age, size, health condition, and nutritional needs of livestock.The specific gravity results obtained in this study were higher when compared to the average commercial feed according to Retnani et al. in 2010 [25], which was 1.37 gr/cm 3 , and lower when compared to the results of the specific gravity of pellets with gamal leaf content according to Royani [26], which ranged from 1.66 -2.00 gr/cm 3

3.2.
The results of research on the porosity of animal feed processed using Equation (2) obtained measurement results as in Table 2. Based on Table 2, the observation results were obtained with an average value of 29.05%.By testing the porosity of animal feed, we can find out how much air is trapped in animal feed, so that it can affect the quality and shelf life of the feed.The test value obtained in this study is lower when compared to the porosity value of silica pellets that have the effect of pressing, which ranges from 36.24 -39.25% [27].

Water absorption
From the dry and wet mass measurement data of the sample, the results of the water absorption measurement are processed with Equation 3, obtained the average value after 5 repetitions according to Table 3.Based on Table 3, the observation results obtained with an average value of 72.62%.The test results have a lower value than the results of research that made biscuits made from Kumpai Oil Grass and swamp legumes (Neptunia oleracca Lour) with water absorption values ranging from 76.58 -88.47% with an average of 84.09% [28].Water absorbency in animal feed refers to the ability of feed to absorb water under certain conditions that can affect feed consumption, digestion, and animal health.testing the water absorption of animal feed is done to determine the characteristics of the feed and can help in determining the right amount of feed and optimal animal health.

Water solubility
Tests were carried out based on the SNI 01-2891-1992 test method.From the test results, the water solubility value obtained was 3.24%.Although the reference value for water solubility is < 100%, the value obtained in this test is very low.Lower solubility values can indicate the presence of feed ingredients that are difficult to dissolve in water, such as high crude fiber content in animal feed ingredients.But conversely, higher solubility values indicate the presence of soluble feed ingredients, such as sugar or salt.

Color and odor
Tests were carried out using the SNI 01-2891-1992 test method.From the tests carried out, the results showed that animal feed from a mixture of palm kernel cake, tofu pulp, bran, and cassava had a brownish color and a normal smell like commercial animal feed in general.The normal color of animal feed depends on the type of feed ingredients used, but in general it is yellowish brown or yellowish green.A normal odor for animal feed is one that is not too strong or sharp and leads to the natural and natural aroma of the feed ingredients used.Striking colors and odors in animal feed can indicate the presence of contaminated feed ingredients, which can affect the quality of the animal feed and the health of the animals that consume it.

Fermentation temperature
The results of temperature measurements carried out during the 8-day fermentation process with a fermentation temperature of 29.87°C, reaching the temperature of maturity on the 8th day of fermentation at 17.00 WIB with a temperature of 38.44°C.The temperature measurement results obtained can be seen in Table 4 and Figure 1.From Table 4 and Figure 1, it can be seen that the fermentation temperature has a value that tends to increase and stabilize.The temperature drops and rises at certain times.This is due to the influence of outside temperature due to the fermentation tank that is not tightly closed and the existence of an air gap due to the cable used in the temperature sensor.However, after the temperature decreased, the fermentation temperature then experienced a steady increase until it could be said to be ripe on day 8 with a temperature of 38.44°C.

Hardness
The results of testing the hardness of animal feed pellet samples using a Hardness Tester, obtained the results as listed in Table 5.From Table 5, it can be seen that the hardness of pellet samples made from palm kernel meal, tofu pulp, rice bran, cassava, molasses, and EM 4 has a hardness value of 4.85.In general, good pellets have a hardness value ranging from 3.92 to 6.37.By testing 5 pellet samples, it was found that each pellet sample had a different hardness value.Varying hardness values are due to the presence of cracks in the pellets as well as different pellet sizes, longer pellets will require greater breaking strength compared to shorter pellets.

Brittleness
Testing the friability of animal feed pellet samples using the Friability Tester with calculations based on Equation 4, obtained the results as listed in Table 6.Table 6 shows that the average result of the friability test on the animal feed pellet sample after 5 repetitions are 4.92%.Brittleness is related to hardness, where the higher the hardness value of the sample, the lower the brittleness value.The effect of feed friability on broiler productivity, the results showed that feed with a low level of friability (<10%) would give better results in terms of body weight, feed conversion, and feed efficiency.
3.9.Proximate analysis 3.9.1.Protein.Protein testing of feed samples was carried out based on the SNI 01-2891-1992 test method.From the test results, the value of protein content in feed samples made from palm kernel meal, tofu pulp, rice bran, cassava, molasses, and EM 4 was 10.5%.This protein content is close to the standard value that has been set.This indicates that the feed mixture has adequate protein content to meet the nutritional needs of livestock.The protein content of feed varies depending on the type of livestock and the purpose for which the feed is used.Based on SNI 3148-2:2017, the protein requirement to fulfill animal feed is at least 12%.The protein content in this study was not significantly different from the protein standard according to SNI 3148-2:2017.
3.9.2.Carbohydrates.Carbohydrate testing of feed samples was carried out based on the SNI 01-2891-1992 test method.From the test results, the value of carbohydrate content in feed samples made from palm kernel meal, tofu pulp, rice bran, cassava, molasses, and EM 4 was 28.5%.The carbohydrate content of animal feed can vary depending on the ingredients used.The selection of carbohydrate content in animal feed should be done carefully and adjusted to nutrition and livestock health.Standard values for carbohydrate content of beef cattle feed range from 40 -60%.Based on standard values, the carbohydrate content of this blend is far from the reference value.
3.9.3.Crude fiber.Crude fiber testing of feed samples was carried out based on the SNI 01-2891-1992 test method.From the test results, the value of crude fiber content in feed samples made from palm kernel cake, tofu pulp, rice bran, cassava, molasses, and EM 4 was 22.8%.Based on SNI 3148-2:2017, a good crude fiber content of cattle feed is between 12 -17%.Crude fiber is an important component in cattle feed that can affect the digestion and health of the cattle's digestive system.Higher or lower crude fiber content can be used depending on the conditions and nutritional needs of beef cattle.Based on the existing standard values, the animal feed with the mixture of ingredients used in this study has a high value than the existing standard.
3.9.4.Total fat.Total fat testing of feed samples was carried out based on the SNI 01-2891-1992 test method.From the test results, the value of total fat content in feed samples made from palm kernel meal, tofu pulp, rice bran, cassava, molasses, and EM 4 was 2.30%.Cattle feed has a standard total fat value that varies between 2 and 4%.The total fat content of animal feed varies depending on the mix of feed ingredients used.The total fat content of these nutrient blends corresponds to applicable guideline values.
3.9.5.Moisture content.Testing the moisture content of feed samples was carried out based on the SNI 01-2891-1992 test method.From the test results, the value of the moisture content in feed samples made from palm kernel meal, tofu pulp, rice bran, cassava, molasses, and EM 4 was 32.9%.Based on SNI 3148-2:2017, the maximum moisture content of cattle is 14%.So by looking at the reference in SNI 3148-2:2017, animal feed samples made from palm kernel cake, tofu pulp, rice bran, cassava, molasses, and EM 4 have a moisture content that is too high.
3.9.6.The ash content.Ash content testing of feed samples was carried out based on the SNI 01-2891-1992 test method.From the test results, the value of the ash content in feed samples made from palm kernel meal, tofu pulp, rice bran, cassava, molasses, and EM 4 was 3.00%.According to Zullaikah et al. [5], the amount of the ash content in a material indicates the high mineral content in the material.Based on SNI 3148-2:2017, a good ash content for cattle is a maximum of 12%.So, by looking at the reference in SNI 3148-2: 2017, animal feed samples made from palm kernel meal, tofu pulp, bran, cassava, molasses, and EM 4 has a good ash content for animal feed.

Conclusion
Animal feed pellets made from palm kernel meal with a mixture of ingredients such as rice bran, tofu dregs, and cassava are considered less than optimal for high-protein animal feed.The mixture has a low nutritional content and does not meet the requirements of ruminant feed according to SNI 3148-2: 2017.It is recommended to vary the composition of the ingredients in order to find the best mixture composition that can improve the quality of animal feed and select the use of ingredients with a high IOP Publishing doi:10.1088/1755-1315/1352/1/0120979 crude fiber content so as not to affect the content of nutrients produced from the mixture of feed ingredients.

Figure 1 .
Figure 1.The graph of fermentation temperature measurement for 8 days.

Table 3 .
Water absorbency test results with 5 repetitions.

Table 4 .
Data of fermentation temperature measurement results for 8 days.

Table 5 .
Hardness testing results with 5 repetitions

Table 6 .
Data on the brittleness test results with 5 repetitions.