Physical quality of floating grower tilapia feed pellets supplemented with different levels of crude palm oil

Wan Nooraida Wan Mohamed, Abidah Md Noh, Nur Atikah Ibrahim, Saminathan Mookiah, Muhammad Amirul Fuat and Mardhati Mohammad¹

Malaysian Palm Oil Board, 6 Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia
wannooraida@mpob.gov.my
¹ Strategic Livestock Research Centre, MARDI Headquarters, Serdang, P O Box 12301, 50774 Kuala Lumpur, Malaysia

Abstract

The production of high-quality animal feed pellets in terms of physical property is crucial since they influence the end product's acceptance. Fish oil is one of the main sources of lipids commonly used in the commercial fish feed industry, but there is limited supply. Palm-based lipids, such as crude palm oil (CPO), are more cost-effective than fish oil and are available all year. This study was conducted to evaluate the physical qualities of floating grower tilapia (Oreochromis niloticus) feed pellets containing different levels of CPO. Four diets, namely control (without CPO inclusion) as well as the treatment fish feed with 5, 8, and 10% inclusion levels of CPO, were formulated to have the same levels of macronutrients. The feeds were extruded and subjected to physical quality, namely, fines, pellet durability index, hardness, floatability, and water stability tests. Fish feeds supplemented with CPO met the standard for fines percentage (<5%) and pellet durability index (>90%), comparable to the control feed. All treated feeds had good floatability, with more than 90% of feed pellets being afloat after 50 min of exposure to water. Meanwhile, the hardness and water stability of treated grower tilapia feed pellets was comparable to that of control feed, ranging between 18.42-19.68 N and 75-85%, respectively. Overall, the addition of CPO in grower tilapia fish diets did not adversely affect the physical quality of floating fish feed pellets, and the quality were comparable to those of the control feed.

Key words: aquaculture, extrusion, feed acceptance, fish feed durability, oil palm lipid

Introduction

Pelleted animal feeds have many advantages, including less wastage, higher feed intake, improved feed efficiency, lower handling costs, convenience of handling and storage, and less bacterial contamination (Amirabdollahian et al 2014; Bentoli 2017; Horses 2019). Production of good quality animal feed pellets in terms of physical property is crucial as they affect the final products’ acceptance and price (Mina-Boac et al 2006; Loar II and Corzo, 2011; Muramatsu et al 2015). Pellets with good physical properties, such as hardness, fines, pellet size, and pellet durability index, are preferred.

Good physical qualities of fish feed pellets can enhance the rate of nutrient absorption by the fish, leading to improved overall fish growth performance (Small et al 2016). Thus, pelleted fish feed must have a certain integrity in order to withstand the force exerted during transportation from the mill to the farm without fragmentation and fines production being subjected to attrition stresses, thereby achieving the feeding benefits for the fish. (Aarseth and Prestløkken 2003; Mina-Boac et al 2006; Robb and Crampton 2013).

In addition to that, the fineness or coarseness of ground feed ingredients also significantly affects the physical property of the finished fish feed pellets, consequently affecting the acceptance of the feed by the fish (Palaniswamy and Ahmad Ali 1991). The fine grind of ingredients frequently enhances the physical quality of the pellet, minimising breaking and fines production while also increasing the digestibility of the fish feed (Heimann 2014; Yasothai 2018).

Another important characteristic of fish feed pellets is their water stability, as the feed comes into contact with water during feeding. A good water stability is important so that the feed pellets can maintain their integrity in water instead of polluting the water (Wan Nooraida et al 2019). Furthermore, the formation of fragments and dust represents a direct loss of feed and feed conversion, thus increasing the production cost (Obirikorang et al 2015).

Lipids play a significant role in fish diets. Fish require dietary lipid as a source of essential fatty acids and energy (Kim et al 2012). Fish oil is one of the main sources of lipids commonly used in the commercial fish feed industry (Qiu et al 2017; Kim et al 2012; Nasopoulou and Zabetakis 2012). Because of the high demand for fish oil, it is relatively expensive and has become a financial burden for many farmers. On top of that, the supply of fish oil is also limited. Lipid feedstock from the oil palm industry has several advantages and opportunities to substitute fish oil in the fish feed industry. Palm-based lipids, such as crude palm oil (CPO), are more cost-effective than fish oil and are available all year.

CPO is extracted from the mesocarp of the oil palm fruit and is highly nutritious due to high levels of carotene (500-700 ppm) and vitamin E (600-1000 ppm) (Nabu et al 2021). It has been demonstrated that the vitamin E (tocopherols and tocotrienols) in CPO can be deposited in the fillets of tilapia fed these diets (Ng and Bahurmiz 2010). The addition of vitamin E to fish diets may increase the tilapia fillets' resistance to oxidation, increasing their shelf life, preventing the development of off-flavour components, losing nutritional value, and even creating molecules that are anti-nutritional (Secci and Parisi 2016; Wan Nooraida et al 2020). Another reason for the higher oxidative stability of tilapia fillets fed this diet is the low concentration of polyunsaturated fatty acids (PUFA) in CPO, as opposed to the high concentration of PUFAs seen in marine lipids like fish oil (Ng and Bahurmiz 2009). The amount of PUFA in tilapia fillets and their susceptibility to lipid oxidation were shown to be linearly correlated (Sampels 2013; Hematyar et al 2019; Harahap et al 2022).

The use of oil in fish feed is an important key to enhancing the growth and sustainability of the aquaculture sector, as well as improving feed qualities, but at higher levels, it may deteriorate the quality of the pellets (Yadav et al 2019). Therefore, this research was conducted to evaluate the physical properties of floating grower tilapia feed pellets supplemented with different percentages of CPO in comparison to control feed pellets.

Materials and methods

Corn, soybean meal, fishmeal, broken rice, rice bran full fat, wheat pollard, and feed additives were purchased from local suppliers. CPO was obtained from Felda Vegetable Oil Product (FVPO), Gebeng, Pahang, Malaysia. The formulation of treatment and control floating tilapia feed diets are presented in Table 1.

Floating Grower Tilapia Feed Pellet Production

The floating grower tilapia feed pellets were produced at Shuzam Feedmill, Seremban 2, Negeri Sembilan, Malaysia. The feed ingredients, e.g., corn, soybean meal, broken rice, rice bran full fat, and wheat pollard, were pulverized using a pulverizer (TPF-250S, SIMA, China) fitted with a 0.35 mm diameter of screen sieve. Following that, the pulverized feed ingredients, together with other feed additives, were weighed according to the feed formulations and mixed in a mixer (MXJ-2000S, SIMA, China) for 10 min before being transferred into an extruder machine (FXJ-1000C, SIMA, China) equipped with a 3 mm diameter die. The temperature of the extruder machine was set at 120 ⁰C and conditioned for 30 sec. The pellets produced were then dried at 110 ⁰C for 3 min in a dryer (BDJ-5×8 1C, SIMA, China) to remove the excessive moisture content. The CPO was added at a rate of 3% in the mixer, and the remaining oil was top coated after the drying process.

Physical Analysis

The physical quality of the floating grower tilapia feed pellets produced was analysed in a laboratory scale study, which included fines, pellet durability index, hardness, floatability, and water stability test. The fines, pellet durability index, and hardness tests were conducted at the Analysis Laboratory, Feed Research Group (FRG), MPOB Keratong Research Station, Pahang, Malaysia. Meanwhile, the floatability and water stability tests were conducted using aquaria which were available at the Aquaculture Complex, FRG, MPOB Keratong Research Station, Pahang, Malaysia.

Fines test

Fines test was conducted using an American Society for Testing and Materials (ASTM) mesh sieve of 2 mm diameter. Five hundred gram of floating grower tilapia feed pellets were weighed (initial weight) and sieved to remove the fines particle from the whole feed pellet. The fines-free feed pellets were then weighed (final weight). Fines percentage of the feed pellets was calculated using the equation below. The fines-free feed pellets were used for pellet durability index determination.

Pellet durability index (PDI)

Pellet durability index (PDI) was measured using a Pellet Durability Tester (NHP100, TEKPRO, UK). Approximately 100 g fines-free feed pellets were weighed (initial weight), inserted into the tester and run for 60 sec. The whole feed pellets left inside the instrument chamber were then weighed (final weight). The PDI was calculated using the equation below.

Hardness

Hardness or breaking force was measured using a digital tablet hardness tester (HT–30/50, Campbell, India). The hardness value was given in force (N) at the breakage point. The measurements were conducted using five randomly selected floating grower tilapia feed pellets and the hardness value was calculated based on the average hardness measurement of the feed pellets.

Floatability

A total of 12 glass aquaria were filled with water of normal salinity for freshwater at a temperature of 25 ⁰C. The glass aquaria were divided into four diets with three replicates (n = 3) of each diet. Twenty (initial number) floating grower tilapia feed pellets were dropped into the respective aquarium. The number of floating grower tilapia feed pellets was recorded at a 5 min interval (final number) for 50 min to plot the floating grower tilapia feed pellets curve. The floatability, expressed in percentage, was calculated using the equation below.

Water stability

A total of 15 floating grower tilapia feed pellets were randomly selected, individually weighed (initial weight) and tied in a nylon sieve materials of 0.1 mm diameter mesh. Then, the tied feed pellets (n = 5 for each treatment) were fixed in four aquariums (one feed diet per aquarium) and left in the water for 50 min. At the end of every 10 min, one of the tied feed pellets was lifted out slowly from the water with the aid of a twine. The wet feed pellet was allowed to drain for 3 min after which the content was put on flat boards, sun-dried for two days, and weighed to obtain the dry matter weight (weight of retained feed pellet). The weight obtained was the leftover from the original weight after the immersion due to each test period’s disintegration. The water stability, expressed in percentage, was calculated using the equation below.

Statistical Analysis

All analyses were done in triplicate. Data collected were subjected to analysis of variance (ANOVA). Mean differences among treatments were analysed by Duncan’s Multiple Range Test using SAS 9.1^TM statistical package (SAS Institute Inc. Cary, North Carolina, USA). Significance was set at p<0.05.

Results

Effects of Oil Palm Lipids on the Formation of Fines, Durability, Hardness, Floatability and Water Stability of Fish Feed Pellets

Figure 1 depicts the fines percentage for floating grower tilapia feed pellets. Except for the 10% CPO treatment, all treated floating grower tilapia feed pellets had lower (p<0.05) fines percentages than the control feed pellet. Despite this, the tilapia fish feed pellets remained within the acceptable level. The fines percentage should not exceed 5% of the feed pellets.

Note: CPO – diet containing crude palm oil; CNT – control diet. Significant differences (p<0.05) between treatment groups are indicated by (ab)

Figure 1. Fines percentage of floating grower tilapia feed pellets with different inclusion levels of crude palm oil

In this study, all feed pellets showed more than 80% PDI, with the floating grower tilapia feed pellet formulated using 8% CPO having a higher (p<0.05) PDI among all treatments with 92%, while the control feed pellet showed lower (p<0.05) PDI among the groups with 89.67% (Figure 2). However, no difference (p>0.05) was observed between the 5 and 10% CPO treatment groups for PDI.

Note: CPO – diet containing crude palm oil; CNT – control diet. Significant differences (p<0.05) between treatment groups are indicated by (abc)

Figure 2. Pellet durability index of floating grower tilapia feed pellets with different treatments

No difference (p>0.05) was observed in the hardness of the floating grower tilapia feed pellet among all treatment groups (Figure 3). The hardness values ranged between 19.68 and 18.42 N, with the highest hardness value coming from the control pellets, while the lowest was from feed pellets formulated with 10% CPO.

Note: CPO – diet containing crude palm oil; CNT – control diet.

Figure 3. Hardness test of floating grower tilapia feed pellets with different treatments

Figure 4 illustrates the percentage of floating grower tilapia feed pellets that remained floating for a total of 50 min, with 5-min interval observations. The grower tilapia feed pellets of 8 and 10% CPO as well as control remained 100% afloat throughout the 50-min experiment. Meanwhile, the floatability of the 5% CPO grower tilapia feed pellet started to drop to 96.7% after 5 min of exposure to water and continued to decrease to 95% from 35 min until the end of the experiment.

Note: CPO – diet containing crude palm oil; CNT – control diet.

Figure 4. Floatability curves of floating grower tilapia feed pellets with different treatments

Figure 5 illustrates the water stability of floating grower tilapia feed pellets. There was a reduction in the water stability of fish feed pellets 10 min after they were inserted into the water. Throughout the 50-min testing, all floating grower tilapia feed pellets demonstrated greater than 76% water stability, with the highest being 10% CPO feed pellets (84.7%), and the lowest being control feed pellets (76.7%).

Note: CPO – diet containing crude palm oil; CNT – control diet.

Figure 5. Water stability curves of floating grower tilapia feed pellets with different treatments

Discussion

Lower fines content is important in aquaculture because fines produced during feed manufacturing will be wasted, polluting the water, and reducing the supply of oxygen and filter capability (Ziggers 2012). The fines in finished feed pellets were probably formed during the feed manufacturing and delivery process by mechanical abrasion on the pellets (De Jong et al 2017; Nur Atikah et al 2018). According to Goh (2015), the presence of fines in finished feed pellets is due to poor cooking of starch and low level of available gelling necessary for good intra-particles bonding. In addition to that, a higher level of lipids in the feed formulation may reduce the quality of the feed pellet due to the partial encapsulation of feed particles that will hinder the penetration of steam, resulting in reduced starch gelatinization and weakened capillary adhesion forces (Muramatsu et al 2015). However, when feed pellets with and without CPO were compared, the pellets without CPO (control feed pellet) had a higher fines percentage than the pellets with CPO. This could be related to the fact that CPO is liquid at high temperatures during processing and semisolid at room temperature, which aids pelleting and improves feed quality at a certain inclusion level in the feed formulation, hence lowering fines production in the finished product. Nonetheless, this issue can be overcome by incorporating natural or synthetic binders, such as wheat pollard and broken rice, as well as adding moisture during the feed production process to form a durable feed pellet. Though some controversies exist, the general observation is that a linear relationship exists between the rate and efficiency of fish growth, and the ratio of pellets to fines. Nevertheless, the relationship between pellet quality in terms of fines content, and fish performance remains largely unquantified.

PDI is commonly used to express pellet quality. The PDI value represents the percentage of pellets that remain intact when mechanical forces are applied (Farahat 2015). The PDI and fines percentage were found to have an inverse relationship, indicating that the higher the PDI, the better the pellet quality (Fahrenholz 2012; Mammeri 2020). Pellet durability is good if it ranges from 80 to 90%, and the best pellet quality has a resistance index of more than 96% (Briggs et al 1999; Dozier 2001; Kiki Haetami et al 2017). The findings from the current study were consistent with Mohammadi Ghasem Abadi et al (2019) and Wan Nooraida and Abidah (2020), who indicated that different levels of fats added to the feed had different effects on the feed durability. High dietary fat inclusion may result in less durable pellets as fat decreases feed ingredients in contact with die-hole walls, resulting in faster feed passing through the die, hence reducing feed compaction inside the die holes (Thomas et al 1998; Briggs et al 1999; Moritz et al 2003; Fahrenholz 2012). According to Muramatsu et al (2015), the post-pellet liquid fat application (PPLA) method is one of the strategies for keeping pellets intact in a high-fat diet. The PPLA increased the PDI from 86% to 97% by adding 25 g of fat per kg of feed after the pelleting process instead of total fat addition in the mixer. Apart from that, the tool size selection, such as the diameter of the die hole, can also affect the PDI value of feed pellets. Reducing the diameter of the die hole will increase the amount of gelatinized starch and frictional forces, resulting in more durable feed pellets (Lee et al 2006).

The hardness index is the best indicator of feed pellet quality as it indicates the degree of gelatinization of the raw starch during feed production. The hardness test revealed no difference (p>0.05) between the floating grower tilapia feed pellets used in the treatment groups and the control group. Dejan et al (2013) reported that the feed pellet diameter and grinding screen size of hammer mill influenced the hardness of the feed pellets. The largest pellet diameter yielded the hardest pellets, while the smallest pellet diameter resulted in the lowest hardness. Other than that, raw starch must be fully gelatinized to ensure strong bonds between particles to improve the hardness of the feed pellet (Feedpelletizer 2018). In view of these factors, the hardness of the feed pellet may be guaranteed.

Floating fish feed is required by the surface feeder fish to easily access feed in water. Floatability is an important measure to monitor the amount of feed intake and acceptability of the floating fish feed (Felix and Oscar 2018). The addition of oil and fat to the fish feed formulation results in a pellet with a longer floating duration, as oil and fat are less dense than water. However, in the current study, the control feed pellets without oil inclusion remained completely afloat throughout the experimental period. In another study, Saalah et al (2010) investigated the floating time and leachability of fish feed pellets using corn flour, soy flour, and tapioca flour with palm stearin. They found that floatability increased in soy and tapioca flour feed formulations while palm stearin showed the least due to the high processing temperature which contributed to leaching and melting of the palm fat out of the feed pellets. Contrary to this finding, our results showed that grower tilapia feed pellets containing CPO at different levels possessed good floatability characteristics of above 95%. This could be because the processing conditions at high temperatures (80-100⁰C) caused the palm stearin to melt and leach out, whereas the current study used spraying technique that coated the final feed pellets produced with the CPO.

Feed pellets that have good water stability is important to minimize wastage of nutrients into the aquatic environment for the slow-eating fish. A water-stable feed pellet ensures nearly wholesome delivery and utilization by the fish (Solomon et al 2011). According to Kannadhason et al (2008), apart from feed digestibility and expansion of feed during the manufacturing process, high starch gelatinization of feed ingredients can also contribute to better water stability. In addition, pellet sizes and protein ratio also affect the water stability of fish feed. It was discovered that increasing the pellet size from 1 to 3 mm increased the mean water stability from 54.15 to 76.51% and 60.65 to 91.78% at 25 and 32% protein ratios, respectively (Khater et al 2014). Meanwhile, Solomon et al (2011) stated that the reduction in particle size of feed ingredients could increase water stability and pellet durability, but was rather expensive.

Conclusion

The floating grower tilapia feed pellets with the addition of different levels of CPO at 5, 8, and 10% of inclusion have shown acceptable physical properties in terms of PDI, hardness, floatability, and water stability, comparable to that of control feed pellets. Thus, there is a prospective possibility of using up to 10% CPO in the production of high-quality fish feed pellets.

Acknowledgements

The authors would like to thank the Director General of MPOB for the permission to publish this paper. The authors also acknowledge the staff of Feed Research Group, MPOB Keratong Research Station, Pahang as well as Strategic Livestock Research Centre, MARDI, Serdang for their assistance in ensuring the success of this study.

References

Amirabdollahian H, Emamzadeh A N and Keramati K 2014 A comparative effect of mash and pellet feed with different pelleting temperature on blood metabolites, carcass characteristics and broiler performance. International Journal of Advance Biological and Biomedical Research, Vol. 2(1), 141-145.

Bentoli 2017 The benefits of pellet binders in broiler chicken feed. Retrieved October 27, 2022, from https://www.bentoli.com/chicken-feed-pellet-binder-benefits

Briggs J L, Maier D E, Watkins B A and Behnke K C 1999 Effects of ingredients and processing parameters on pellet quality. Poultry Science, 78, 1464-1471. https://doi.org/10.1093/ps/78.10.1464

De Jong J A, DeRouchey, J M, Tokach M D, Goodband R D, Woodworth J C, Dritz S S, Stark C R, Jones C K, Williams H E, Erceg J, Haberl B, McKinney L J, Smith G, Van Otterloo D and Paulk, C B 2017 Formation of pellet fines during the feed manufacturing process, transportation and feed line delivery, and their nutrient composition. Applied Engineering in Agriculture, 33(6), 921-926. https://doi.org/10.13031/aea.12304

Dejan M, Mette S and Birger S 2013 Strength and durability of feed pellets influenced by different particle size distribution, pellet volume and dehydration techniques. Annual Transactions of the Nordic Rheology Society, 21, 107-115.

Dozier W A 2001 Pellet quality for most economical poultry meat. Feed International, 52(2), 40-42.

Fahrenholz A C 2012 Evaluating factors affecting pellet durability and energy consumption in a pilot feed mill and comparing methods for evaluating pellet durability. Ph.D. thesis, Kansas State University, Manhattan, Kansas, pp. 104.

Farahat M H 2015 Good quality feed pellets: Does it make sense? Retrieved July 1, 2021, from https://www.allaboutfeed.net/animal-feed/feed-processing/good-quality-feed-pellets-does-it-make-sense

Feedpelletizer 2018 How to regulate the hardness of pellet feed. Retrieved May 19, 2021, from https://www.feedpelletizer.com/application/how-to-regulate-feed-pellet-hardness.html

Felix E and Oscar E V 2018 Floating and stability effect on fish feed pellets using different concentration of baobab leaf meal (Adansonia digitata). Asian Journal of Fisheries and Aquatic Research, 1(4), 1-6. https://doi.org/10.9734/ajfar/2018/v1i4348

Goh S 2015 Role of proper steam conditioning – starch gelatinization. Asian Feed Magazine – Dec 2015 / Jan 2016, pp. 6.

Harahap I A, Sobral M M C, Casal S, Pinho S C M, Faria M A, Suliburska J and Ferreira I M P L V O 2022 Fat oxidation of fatty acid vs. meat meal diets under in vitro standardized semi-dynamic gastric digestion. Frontiers in Nutrition, 9: 901006. https://doi.org/10.3389/fnut.2022.901006

Heimann M 2014 Grinding considerations when pelleting livestock feeds. In: Feed Pelleting Reference Guide. Kansas State University, Manhattan, Kansas, USA, pp.18.

Hematyar N, Rustad T, Sampels S, Dalsgaard T K 2019 Relationship between lipid and protein oxidation in fish. Aquaculture Research, Vol. 50(5), 1393-1403. https://doi.org/10.1111/are.14012

Horses 2019 What are the advantages and disadvantages of pelleted feed for horses. Retrieved October 27, 2022, from https://horses.extension.org/what-are-the-advantages-and-disadvantages-of-pelleted-feeds-for-horses

Kannadhason S, Muthukumarappan K and Rosentrater K A 2008 Effect of starch sources on extruded aquaculture feed containing DDGS. Food and Bioprocess Technology, 4(2), 282-294. https://doi.org/10.1007/s11947-008-0177-4

Khater E G, Bahnasawy A H and Ali S A 2014 Physical and mechanical properties of fish feed pellets. Journal of Food Processing and Technology, 5, 378. https://doi.org/10.4172/2157-7110.1000378

Kiki Haetami, Junianto, Iskandar, Rita Rostika and Abun 2017 Durability and water stability of pellet fish supplementation results pairing coconut oils and hazelnut oils. International Journal of Environment, Agriculture and Biotechnology, 2(3), 1336-1340. https://doi.org/10.22161/ijeab/2.3.40

Kim D K, Kim K D, Seo J Y and Lee S M 2012 Effects of dietary lipid source and level on growth performance, blood parameters and flesh quality of sub-adult olive flounder ( Paralichthys olivaceus). Asian-Australasian Journal of Animal Sciences, 25(6), 869-879. https://doi.org/10.5713/ajas.2011.11470

Lee M H, Lim C E and Webster C D 2006 Tilapia: biology, culture and nutrition. In: Feed formulation and manufacture, Lim, C.E., Webster, C.D. (Eds.), The Haworth Press, New York, pp. 517-559.

Loar II R E and Corzo A 2011 Effects of feed formulation on feed manufacturing and pellet quality characteristics of poultry diets. World's Poultry Science Journal, Vol. 67 (1), 19-28. https://doi.org/10.1017/S004393391100002X

Mammeri M 2020 Optimizing pellet processing to boost pellet quality and profitability. Retrieved August 25, 2021, from https://phileo-lesaffre.com/en/optimising-pellet-processing-to-boost-pellet-quality-and-profitability

Mina-Boac J, Maghirang R G and Casada M E 2006 Durability and breakage of feed pellets during repeated elevator handling. In American Society of Agricultural and Biological Engineers (ASABE) Annual Meeting, 12 pp. Kansas State University, Manhattan, Kansas. https://doi.org/10.13031/2013.21447

Mohammadi Ghasem Abadi M H, Moravej H, Shivazad M, Karimi Torshizi M A and Kim W K 2019 Effect of different types and levels of fat addition and pellet binders on physical pellet quality of broiler feeds. Poultry Science, 98(10), 4745–4754. https://doi.org/10.3382/ps/pez190

Moritz J S, Cramer K R, Wilson K J and Beyer R S 2003 Feed manufacture and feeding of rations with graded levels of added moisture formulated to different energy densities. The Journal of Applied Poultry Research, 12 (3), 371-381. https://doi.org/10.1093/JAPR/12.3.371

Muramatsu K, Massuquetto A, Dahlke F and Maiorka A 2015 Factors that affect pellet quality: A review. Journal of Agricultural Science and Technology, 5, 717-722. https://doi.org/10.17265/2161-6256/2015.09.002

Nabu E B P, Sulaswatty A and Kartohardjono S 2021 Palm carotene production technologies – A membrane perspective. In IOP Conference Series: Materials, Science and Engineering 1053, pp. 16. International Conference and on Chemical and Material Engineering, Semarang, Indonesia. https://doi.org/10.1088/1757-899X/1053/1/012136

Nasopoulou C and Zabetakis I 2012 Benefits of fish oil replacement by plant originated oils in compounded fish feeds. A review. LWT - Food Science and Technology, Vol. 47(2), 217-224. https://doi.org/10.1016/j.lwt.2012.01.018

Ng W K and Bahurmiz O M 2009 The impact of dietary oil source and frozen storage on the physical, chemical and sensorial quality of fillets from market-size red hybrid tilapia, Oreochromis sp. Food Chemistry, Vol. 113(4), 1041-1048. https://doi.org/10.1016/j.foodchem.2008.08.060

Ng W K and Bahurmiz O M 2010 Palm oil replaces fish oil in tilapia feed: Substitution also increases shelf life. Global Aquaculture Advocate, March/April 2010, pp. 69-70.

Nur Atikah I, Wan Nooraida W M, Abidah M N and Miskandar M S 2018 Chemical and physical analyses of goat feed pellets with oil palm by-products inclusion. Palm Oil Developments, 69, 25-27.

Obirikorang K A, Amisah S, Fialor S C and Skov P V 2015 Effects of dietary inclusions of oilseed meals on physical characteristics and feed intake of diets for the Nile Tilapia, Oreochromis niloticus. Aquaculture Reports, 1, 43-49. https://doi.org/10.1016/j.aqrep.2015.01.002

Palaniswamy R and Ahmad Ali S 1991 The impact of particle size of ingredients in compounded diets on pellet stability and performance in Penaeus indicus H. Milne Edwards. Journal of Aquaculture in Tropics, 6, 119-127.

Qiu H, Jin M, Li Y, Lu Y, Hou Y and Zhou Q 2017 Dietary lipid sources influence fatty acid composition in tissue of large yellow croaker (Larmichthys crocea) by regulating triacylglycerol synthesis and catabolism at the transcriptional level. PLoS One, 12(1), e0169985. https://doi.org/10.1371/journal.pone.0169985

Robb D H F and Crampton V O 2013 On-farm feeding and feed management: perspectives from the fish feed industry. In on-farm feeding and feed management in aquaculture. (eds. Hasan, M., New, M.B.), pp. 489–518. FAO Fisheries and Aquaculture Technical Paper, Rome, Italy.

Saalah S, Shapawi R, Othman N A and Bono A 2010 Effect of formula variation in the properties of fish feed pellet. Journal of Applied Sciences, 10(21), 2537-2543. https://doi.org/10.3923/jas.2010.2537.2543

Sampels S 2013 Oxidation and antioxidants in fish and meat from farm to fork. In: Food Industry, Muzzalupo I (Ed.) IntechOpen, London, pp. 760. https://doi.org/10.5772/53169

Secci G and Parisi G 2016 From farm to fork: lipid oxidation in fish products. A review. Italian Journal of Animal Science, 15:1, 124-136. https://doi.org/10.1080/1828051X.2015.1128687

Small B C, Hardy R W and Tucker C S 2016 Enhancing fish performance in aquaculture. Animal Frontiers, Vol. 6(4), 42-49. https://doi.org/10.2527/af.2016-0043

Solomon S G, Ataguba G A and Abeje A 2011 Water stability and floatation test of fish pellets using local starch sources and yeast (Saccahromyces cerevisae). International Journal of Latest Trends in Agriculture and Food Sciences, 1(1), 1-5.

Thomas M, Viliet T and Van der Poel A F B 1998 Physical quality of pelleted animal feed. 3. Contribution of feedstuffs components. Animal Feed Science and Technology, 70 (1-2), 59-78. https://doi.org/10.1016/S0377-8401(97)00072-2

Wan Nooraida W M, Abidah M N and Nur Atikah I 2019 MPOB animal feed pilot plant. Palm Oil Developments, 70, 9-18.

Wan Nooraida W M and Abidah M N 2020 Effects of pellet supplemented with different percentages of oil palm lipid sources on broiler performance, carcass trait and feed quality. Journal of Oil Palm Research, Vol. 32(2), 313-325. https://doi.org/10.21894/jopr.2020.0021

Wan Nooraida W M, Abidah M N, Nur Atikah I, Mookiah S, Muhammad Amirul F and Rafidah A H 2020 Sensory evaluation of fillets from tilapia (Oreochromis niloticus) fed diets containing oil palm lipids. Journal of Oil Palm Research, Vol. 34(1), 177-183. https://doi.org/10.21894/jopr.2020.0108

Yadav M K, Ojha, Keer N R and Yadav A 2019 An overview on the use of oil in fish diet. Journal of Entomology and Zoology Studies, 7(1), 883-885.

Yasothai R 2018 Factors affecting pellet quality. International Science, Environment and Technology, Vol, 7, No 4, 1361-1365.

Ziggers D 2012 The better the pellet, the better the performance. Retrieved April, 15, 2021, from https://www.allaboutfeed.net/animal-feed/feed-additives/the-better-the-pellet-the-better-the-performance