Feed processing based on palm kernel meal-indigofera in mash, silage, pellet and wafer forms for sheep

Triami Lestari¹, Yuli Retnani², Iwan Prihantoro², Sri Suharti², Taryati², Nisa Nurmilati Barkah² and Novia Qomariyah^3,4

¹ Graduate School of Animal Nutrition and Feed Science, IPB University Department of Animal Nutrition and Feed Technology, Faculty of Animal Science, IPB University, Bogor 16680, Indonesia
triami09.triami@apps.ipb.ac.id
² Department of Nutrition and Feed Technology, Faculty of Animal Science, IPB University, Bogor 16680, Indonesia
³ Research Center for Animal Husbandry, Research Organization for Agriculture and Food, National Research and Innovation Agency (BRIN), Cibinong Sciences Center, Cibinong, Bogor, Indonesia
⁴ Animal Feed and Nutrition Modelling Research Group, Faculty of Animal Science, IPB University, Bogor 16680, Indonesia

Abstract

Increasing the availability and fulfillment of animal feed is important for the sustainability of the livestock business. Indigofera and Palm Kernel Meal (PKM) is a combination of tree legumes and by-products of the plantation industry that can be used as a complete feed. This study aimed to evaluate the quality of complete feed based on palm kernel meal-Indigofera in the form of mash, silage, pellet, and wafer. A total of 20 male sheep were randomly allocated to 5 feed treatments with 4 replications. The feeding treatments were completed feed based on PKM-Indigofera in the form of feed mash (P1), silage (P2), pellet (P3), and wafer (P4). The result showed that feed treatments affected (p<0.05) physical characteristics, feed consumption, final body weight, body weight gain, feed efficiency, and income over feed costs. Pellet feed (P3) had the lowest value for water content and water activity, with the highest bulk density value, i.e. 7.30%, 0.60%, and 1.17 g/cm3 respectively. In vitro tests showed that the highest value of feed digestibility was in wafer (P4) with NH3 values of 11.32 mM, VFA 123.08 mM, KCBK 67.33%, and KCBO 64.88%. In vivo tests showed that wafer feeding (P4) produced the best sheep performance, with final body weight of 26.64 kg, body weight gain 136.19 g/head/day, and feed efficiency 15.48%. It was concluded that feed processing based on PKM-Indigofera in wafer form (P4) showed the best results on in vitro feed quality and sheep performance compared to other treatments.

Keywords: industry by-product, feed form, physical properties, feed digestibility, performance

Introduction

The fulfillment of the need for animal feed can use ingredients derived from abundant plantation industry by-products such as palm kernel meal (PKM). The nutrient content of PKM consists of 92.1% dry matter, 15.9% crude protein, 9.4% crude fat, and 3.9% ash (Prasetya et al 2021). The level of palatability and digestibility of PKM which is still low is an obstacle to the utilization of PKM as a source of quality animal feed. Supriyati and Haryanto (2011) said that the problem encountered in using PKM as animal feed is the low digestibility due to the shell (shell) and the presence of soluble protein content so the protein component of palm kernel cake will soon be degraded in the rumen into carbon and ammonia chains. Therefore, efforts are needed to inhibit the rumen degradation process so that palm kernel meal protein can reach the post-rumen digestive tract and function as a source of amino acids for livestock.

Efforts that can be made to increase the use value of PKM are Indigofera zollingeriana supplementation. Indigofera is a leguminous plant with high protein, calcium, and phosphorus content. Indigofera produces better biomass production and nutritional quality than other leguminous species (Abdullah 2014). Indigofera's production potential is 51 tons fresh/ha/harvest with a proportion of stem and leaf production of around 63.57% and 36.43% (Sirait et al 2012). The nutritional content of Indigofera PK was 24.17%, LK 6.15%, BK 21.97%, SK 17.83%, and BETN 38.65% (Solikah et al 2020).

Feed processing is an activity carried out to produce quality feed. Effective feed processing increases the use-value of ingredients, including increasing digestibility, increasing palatability, and increasing shelf life. According to Tsaniyah and Hermawan (2015), physical processing (cutting, boiling, making pellets, etc.), chemical processing (adding chemicals such as NaOH and Ca), and biological processing (adding enzymes, fungi, or bacteria) or a combination of several effective treatments increase the palatability and digestibility of feed. Complete feed processing based on PKM-Indigofera needs to be done in an effort to increase the use value of PKM as a by-product of the oil palm plantation industry as a quality complete feed product. Some of the processing that is commonly carried out is the processing of feed in the form of mash, pellets, wafers, and silage.

Mash feed is feed that has undergone a grinding process so that the particle size becomes small (flour). Pellet feed is a mechanical process that uses a combination of water vapor, heat, and pressure. Wafer feed is feed that is processed using heating and pressing. Silage feed is a feed processing product through a fermentation process with the help of anaerobic microorganisms. Pujaningsih et al (2013) explained the benefits of feed processing are increasing the density of the feed thereby reducing drag, reducing storage space, reducing transportation costs, and facilitating the handling and serving of feed.

Until now, the evaluation of PKM-Indigofera-based complete feed products through different processing related to their physicochemical quality, in vitro fermentability quality, and their effectiveness in sheep (in vivo) has not been carried out. The aim of this study was to evaluate the quality of complete feed based on PKM-Indigofera in the form of mash, silage, pellets, and wafer.

Materials and methods

Ethical approval

The cannulation surgery of animals was carried out by a licensed veterinarian and followed the protocol for handling and care of animals, according to the IPB University Animal Ethics Committee.

Feed processing

The feed formulation in this study was based on Kearl (1982) for sheep with a body weight of 20 kg and a body weight gain of 150 g/head/day. The formulation is carried out using the trial and error method. The feed ingredients and chemical composition of feeding treatments are presented below.

Feed processing of making complete feed using the main ingredients of Indigofera and palm kernel meal. Indigofera is processed through chopping, drying, and grinding. The method of making mash feed is carried out by mixing all the ingredients according to the formulation (Table 1) using a WLH200 mixer machine with a capacity of 100 kg. Part of the mash will be processed into silage feed, pellets, and wafers. Silage-making is done by adding 5% lactic acid bacteria (BAL) in EM4 to the feed mixture. After that, anaerobic packaging is carried out and fermented for 3 weeks. Pellet is made through grinding, mixing, conditioning, and pelleting processes. The presence of heating at a temperature of 75-87°C for 15-20 seconds in the conditioning process can increase the content of linked starch (Soltani et al 2020). The wafer feed production process is through grinding, mixing, pressing, and heating at a temperature of 120°C for 10-15 minutes.

Animals and experimental design

A total of 20 Indonesian local rams with an average body weight of 20 kg of livestock were randomly given 5 different feed management treatments, namely: P1: mash-shaped feed containing PKM-Indigofera, P2: silage-shaped feed containing PKM-Indigofera, P3: pellet-shaped feed containing PKM-Indigofera, P4: wafer-shaped feed containing PKM-Indigofera consisting of 4 replays with 1 head per repeat. Sheep are kept in individual pens to avoid eating feed from other sheep. The feed is given consists of complete feed in the mash, silage, pellet, and wafer shape. Every day sheep is given feed in the morning and evening with drinking water given ad libitum . The composition and nutrient content of the research feed can be seen in Table 1. Sheep are kept in individual pens for 2 months carrying out a period of feed adaptation for the first 2 weeks. Before the adaptation period, as much as 2 mL of Albendazole is administered orally to each sheep to minimize diseases resulting from helminth infections. Sheep feeding is carried out in the morning and evening. The remaining feed from each treatment will be weighed every day. The shapes of the complete feed containing PKM-Indigofera that was used in this study are presented in Photo 1.

Photo 1. (a) mash, (b) silage, (c) pellet, (d) wafer

Sampling and measurements

Physical tests that include water content using the PM-650 Grain Moisture Tester tool, water activity using a hygrometer (Aw-Wert-Messer Lufft, 5803.00) (Leistner and Rodel 1976), and specific gravity using the Lopez et al (1996) method, namely dividing the weight of feed (g) by changes in the volume of aquades (L), as well as conducting chemical testing to determine the nutrient content of feed according to the standard procedure method of the Association of Official Analytical Chemists (AOAC 2005). Evaluation of the quality of complete feed products was carried out in vitro using the Tilley and Terry (1963) method, which included dry matter digestibility (DMD), organic material digestibility (DMO), VFA, and NH3 using the Conway dish micro diffusion method (Conway 1957). Evaluation of sheep performance is measured through feed nutrient consumption, average daily accretion, the efficiency of ration use, and income over feed cost (IOFC). Nutrient consumption of feed is calculated based on feed consumption with nutrient content in it. Nutrient consumption measurements consist of dry matter (DMI), crude protein (CP), ether extract (EE), crude fiber (CF), and nitrogen-free extract (NFE). The average weight gain (ADG) of sheep is measured once every 2 weeks to determine body weight gain. The efficiency value is obtained from feed consumption and weight gain during maintenance.

Statistical analysis

Data obtained from this study were analyzed using ANOVA (analysis of variance) through SPSS v 20.0 and one sample T-test. Then, the significantly different data among treatment groups were determined using Duncan's Multiple Range Test (DMRT) and considered at p<0.05.

Results and discussion

Influence of Physical Properties

The physical characteristics of feed describe the quality of a feed. The physical quality of complete feed based on PKM-Indigofera are presented in Table 2.

Water content is an important factor in determining a feed's quality. Based on the results of the various analysis shows that the treatment has a significant effect on the value of water content (p<0.05). Pellet feed (P3) produces the lowest average moisture content value of 7.30±0.45. While the highest average water content value is found in silage feed (P2) which is 25.08±0.55. The occurrence of differences in water content is due to different processing factors. The occurrence of high suppression can cause the water content contained in the feed ingredients to be reduced. In addition, heating that occurs in the pelleting process can cause hydrolysis so that denaturation (heat process) occurs. During the conditioning process, the starch contained in the feed ingredients is suspected of affecting the gelatinization process. During such gelatinization, the starch granules can swell and may cause the granules to burst. The rupture of the granules causes the pellets to have a high enough density that cannot be occupied by water in the material because there are no cavities between particles, so when the granules break, the water will evaporate. This causes the moisture content in the pellets to be low and has an influence on long shelf life. According to Trisyulianti et al (2003), feed that has a moisture content level of 12% to 14%, is able to suppress the growth of microorganisms that cause feed not to easily rot and mushroom when stored.

The growth of microorganisms is closely related to the activity of water in the feed. Based on the results of the various analysis shows that the treatment has a significant effect on water activity (p<0.05). Pellet feed (P3) produces the lowest average water activity value (0.60±0.00). While the highest average value obtained silage feed (P2), which is (0.83±0.01). This difference in water activity can occur due to differences in treatment during feed processing. The low value of water activity in pellet-shaped complete feed is caused by the split of hydrogen bonds due to heat during treatment. This causes the water content in the pellet constituent materials to decrease. This will inhibit the development of microorganisms in feed products, making their storage safer and more durable. High levels of water activity can affect the growth of mold, yeast, and bacteria. For example, mold: 0.60-0.70; yeast: 0.80-0.90; bacteria: 0.90 (Belitz 2009; Wang et al 2012). This shows that microbes do not grow on feed mash, pellets, and wafers because the water activity value is below the growth point of microbes. While silage feed is more susceptible to microbial growth.

Specific gravity is the ratio of the mass of the material to its volume. The results of the variance analysis showed that the treatment had a noticeable effect (p<0.05) on specific gravity. Silage feed (P2) produces the lowest average specific gravity value of 0.87 g/cm³. While the highest average specific gravity value is found in pellets (P3). The high average specific gravity value of P3 is caused by the conditioning process as well as the pelleting process. Through the conditioning and pelleting process, the shape of the pellets becomes more compact and has a good level of hardness. This is in accordance with the opinion of Thomas et al (1996), conditioning is the process of changing the mash ration when mixed using heat, water, pressure, and time for a physical state that facilitates the compaction of the ration. Added by the opinion of Bertipaglia et al (2010), feed with high specific gravity is easier to contact with microbes and enzymes of the gastrointestinal tract.

Characteristics of Rumen Fermentability In Vitro

In vitro digestibility describes the quality of feed through an artificial digestion process adapted to the rumen digestion mechanism. Details of the quality test of complete feed based on PKM-Indigofera complete are presented in Table 3.

The occurrence of protein overhaul in the rumen and microbial protein synthesis can be known through ammonia concentrations. Ammonia concentrations can affect the growth and synthesis of microbial proteins; this is because 60 to 80% N of bacteria are derived from N-ammonia (Kim et al 2014). The normal range of NH3 to support optimal rumen microbial growth is 6-21mM (McDonald et al 2010). The results of the T-test showed that differences in the form of complete feed based on PKM-Indigofera affected (p<0.05) the content of NH3. Silage feed (P2) produced the highest concentration of NH3. The increase in NH3 is due to the high content of easily dissolved protein in silage (P2), making it easier to ferment into NH3. This is supported by Holik et al (2019), whom that high-feed protein can increase the concentration of NH3 in ruminants. NH3 results are related to volatile fatty acids (VFA) production.

The concentration of VFA produced in this study shows that the VFA concentration in each treatment is still at the optimum range for rumen microbial growth. This is in accordance with Suningsih and Sudjadi (2020) that the optimum rumen VFA concentration range for rumen microbial growth is 80-160 mM. The results of the T-test showed that the treatment had a noticeable effect on the concentration of VFA (p<0.05). The addition of EM4 in silage feed (P2) can improve the performance of rumen microbes in fermenting feed. EM4 contains a culture of a mixture of fermented microorganisms, namely lactic acid bacteria (Lactobacillus casei) and yeast (Saccharomyces cerevisiae) (Ardita et al 2015). The increase in VFA suggests that microbes, especially bacteria within the rumen fluid, can degrade the carbohydrate source of the ration to glucose (Hindratiningrum et al 2011; Araujo et al 2015), subsequently produced VFA with a reasonably high volume. VFA production reflects the degradability of organic matter, including carbohydrates and crude proteins, in the rumen to increase feed digestibility.

The results of the T-test showed that the treatment had a noticeable effect (p<0.05) on the Dry Matter Digestibility (DMD). The results showed that the highest value was in the wafer feed (P4) when compared to the other treatments. The high digestibility of dry matter in wafer feed is caused by physical processing of feed ingredients such as the smaller particles of the material due to grinding, making it easier for microbes to digest. In addition, the addition of molasses and cassava is a source of energy for microbes in breaking down feed ingredients which results in higher digestibility, as well as heating and pressing processes that affect the crude fiber content. The presence of wafer-shaped feed processing tends to be lower than in other forms of feed. Yanuarianto et al (2021) stated that feeds with low crude fiber are generally easier to digest because the cell walls of these materials are thin so that microbes can easily penetrate them. The digestibility value of the organic matter in each treatment ranged from 60.11%-64.88%. Based on Table 3, the complete PKM-Indigofera wafer-shaped feed has a higher dry matter digestibility than other feed forms. This affects the digestibility of organic matter which is equal to 64.88%. The main factor that can affect the digestibility of organic matter is the digestibility of dry matter (Nurlaili et al 2014).

Effect of treatment on nutrient consumption

Feed consumption is interconnected with the amount of feed consumed by livestock during rearing which greatly affects livestock productivity. The level of nutrient consumption of sheep during rearing is presented in Table 4.

The type of feed, livestock, and the environment can affect consumption rates (McDonald et al 2002). Based on the results of statistical tests in Table 4 that the treatment affected (p<0.05) dry matter (DM) consumption. The average consumption of dry matter in this study ranged from 888.54-1,178.95 g/head/day. This difference in DM consumption is thought to be caused of palatability the feeding treatments. Palatability is a major factor that explains the difference in dry matter consumption between feed and low-yielding livestock. Feed palatability is generally associated with the high digestibility of a feed (Salam 2017). Table 4 showed the best feed consumption is obtained from wafer feed with an average consumption of 1,178.95 g/head/day. The dense shape of wafer feed and its blending with a distinctive aroma gives wafer feed several advantages, one of which is that it can increase palatability.

Figure 1. Effect of PKM-Indigofera on various types of feeding treatments on DM intake

Effect of feeding treatments on weight gain

Performance is an indicator that can determine the effectiveness of a feed. The effect of feeding treatment on sheep performance during the study is presented in Table 5.

Figure 2. Effect of PKM-Indigofera on various types of feeding treatments on daily gain	Figure 3. Effect of PKM-Indigofera on various types of feeding treatments on feed efficiency

Body weight gain is one of the indicators for measuring the growth of livestock. The results of the study in Table 5 showed that feeding treatment affected (p<0.05) daily body weight gain in sheep. The P4 (wafer) treatment had the highest daily body weight gain effect of 180.36 g/head/day. This is due to the increased consumption of wafer feed (P4) in sheep, as shown in Table 5, with an average dry matter consumption of 1,178.95 g/head/day. Nurjannah et al (2019) stated that rations with high quality and palatability value could accelerate growth and weight gain. Rusdiana et al (2020) stated that the process of rapid growth in sheep will occur at the beginning of their life until puberty, and further growth slows down by the time the sheep reach adulthood. Weight growth is an indicator that states that the higher the rate of weight gain, the higher the feed efficiency value.

Feed efficiency is the ratio of weight gain of livestock with feed consumed by livestock within a predetermined period. Table 5 shows that the treatment had affected (p<0.05) feed efficiency. P4 (wafers) treatment had the highest feed efficiency value of 15.48±2.54 which is not affected differently from P3 (pellet) and P1 (mash), but it differs from P2 (silage) treatments. The highest value of feed efficiency indicates that the feeding consumption is better converted into the product yield in livestock (weight gain). Feed efficiency for meat production is influenced by several factors, namely the nation of livestock, composition, level of production, and nutritional value of feed (Salim 2013). The level of feed protein influences the high feed efficiency. This indicates that the crude protein content in the wafer feed consumed can be converted into meat properly, resulting in optimum weight gain. According to Frank et al (2011) that the energy level of protein in feed affects the efficiency and effectiveness of feed utilization.

Conclusion

Pellet feed (P3) had the lowest value for water content and water activity, with the highest bulk density value. In vitro test showed that the highest value of feed digestibility was in wafer form (P4). In vivo feeding treatment showed that giving wafers (P4) resulted in the best sheep performance.

Acknowledgment

This research is funded by PT Perkebunan Nusantara IV with grant number 24/IT3.F4/HK.07.00-4/P/B/2022 and 04.03/S-Perj/21/IX/2022.

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