Identificationand production palm kernel cakePalm kernel cake is agro-industrial by-product which obtainedfrom palm oil extraction in cultivated tropical rain countries laying between 12°Nand 12°S, such as Indonesia,Malaysia and Nigeria (Olorede and Longe, 2000).Indonesia and Malaysia are the largest producer and exporter ofpalm oil and palm oil by-products while, Nigeria, Colombia and Thailand are recordedless than 10% of the world production (FAO, 2012).When the palm fruits are processed. It is produced palm oil, palm kernelcake and meal according to the method of extraction.
Palmkernel palm resulted from the mechanical expeller procedure contains 5-12% oilwhile, palm kernel meal obtained from solvent extraction technique contains 0.5-3% oil Okeudo et al., (2005). Palm kernelcake has been used as afeed for various livestock production (Ojewoleet al.
, 2003; Pickard, 2005; Okai et al.,2006; FAO, 2012; USDA, 2013). Severalstudies reported that the animals performed satisfactorily well when fed on dietscontaining levels of palm kernel cake. 2.
Chemicalcomposition of palm kernel cake The chemical composition of palm kernel cakevaries (crude protein, crude fiber, ether extract, ash and nitrogen free-extract) depending on the sources of the samples (Rhule, 1996 & Omara etal., 1999), soil type, method of processing oil extraction (e.g mechanicalor solvent extraction), the amount of endocarp remaining (Alimon, 2004;Sundu et al., 2006; Adesehinwa, 2007) and the efficiency of oil extractionfrom the kernel (Onwudike, 1986; Onuh et al., 2010). The chemicalcomposition of palm kernel cake by different studies are shown in table 1.
Dry matterrefers to proportion of moisture in the palm kernel cake. The dry mattercontent is important to determination bulk purchasing and storage of palmkernel cake. Increasing moisture content than 14% could not be stored in bulkand it is the best culture for the molds growing on it (Hartley, 1988).Dry matter of palm kernel cake was recorded a range of 89.
00 – 95.00% byseveral studies (Mustaffa etal., 1987; Chin, 1991; Daudu, 2007; Wallace et al.
, 2010; Akinyeye et al.,2011). Palmkernel cake is low in crude protein content compared with soybean meal andgroundnut cake. Various literature have indicated that the crude proteincontent of palm kernel cake ranges between 14 – 20 % (Sundu et al.,2005; Atil, 2009; Akinyeye et al.,2011). Protein content of palmkernel cake had poor amino acid balance, lysine followed by methionine,tryptophan, threonine and histidine contents (McDonald et al.
, 1995;Olomu, 1995; Rhule, 1996; Sundu et al., 2005; Ezieshi and Olumu, 2007;Boateng et al., 2008) being the major limiting amino acids.
The amino acid profile of Palm Kernel is shown in table2. The crude fibre is consists mainly of cellulose, hemicellulose andlignin. Crude fibre is an index that can used to be predict the feeding valueand nutrients digestibility of the feeds.
There was reversed relationshipbetween crude fibre and nutrients digestibility to the animals (Onuora andKing, 1985; Alimon, 2004). The composition of crude fibre content ofmechanically extracted was lower compared to solvent extracted of palm kernelcake (Olumu and Ezieshi, 2007). The crude fibre content of palm kernelcake was about 6% (Adesehinwa et al., 2007) to 24.9% (Onifadeand Babatunde, 1998). Also, acid detergent fibre being 43.7%, neutraldetergent fibre being 66.
7% and lignin being 21.1% of palm kernel cake (Chin,1991; Sundu & Dingle, 2003). The sugar content in the cell wall of palmkernel cake fibre was mainly contributed by 56.4% mannose, followed by 11.6%glucose, 3.7% xylose and 1.
4% galactose (Anon, 2002; Marini et al., 2005).Ether extract of solvent extracted palm kernel cake was low 0.5 to 3% whilethe expeller pressed contained between 4.5 to 19.5% (Daudu, 2007&Adesehinwa et al.
, 2007). The total ash content of palm kernel cake asrecorded by various studies ranges between 3.06 and 5.6% (Adesehinwa etal.,2007; Bello et al.
, 2008; Akinyeye et al., 2011).palm kernel cake is relatively high in minerals content were calcium0.276%,phosphore 0.645%, magnesium 0.158%, zinc 0.214%, sodium0.187%, potassium0.
365%, cupper 0.25%, manganese 1.3ppm and iron, 0.75ppm (Akinyeye et al.,2011). It was observed that the Ca:P ratio is low and most diets based onpalm kernel cake need to be supplemented with calcium to cover the requirementof animals.
carotene and vitamin E (about 0.3 IU/kg). 3. Enhancingnutritive value of palm kernel cakeVarious treatments of agro-industrialand agriculture by-products could improve their NDF, ADF and hemicellulosecontent (Lui et al.
, 1999; Abd El Tawab 2015, 2016). Until nowthere is no study has been investigated on the effect of physical treatments ofpalm kernel cake on its nutrient contents (Sharmila et al 2014). But,combination of physical and chemical processes could be enhanced nutrient contentsof palm kernel cake (Ng, 2004).The chemical treatments of palm kernelcake using alkaline (ammonium hydroxide) or acid (acetic and formic acids)solution has been suggest to enhance the palm kernel cake nutrientsdigestibility and nutritive values by increasing the crude protein anddecreasing the crude fibre contents (A’dilah and Alimon, 2011).
Also,chemical treatment processes using alkaline and/or acid solution acids can beused as delignification agents to decrease lignin content of palm kernel cake.The degradation of lignin could be affected by the concentration of the acidsolution. There are relationship between using higher concentration of the acidused, and more lignin could be removed (Ng, 2004). While, using alkaline solution to treat palmkernel cake can be absorbed into the cell wall and thus hydrolysis the esterchemical bonds between cellulose, hemicellulose and lignin which finally makethe structural fibre to swell (Chenost and Kayouli, 1997). The biological treatment have been used toincrease the nutritional value of palm kernel cake.
High level of non-starch polysaccharidescontents of the cell wall of palm kernel cake contributes to reducedigestibility of its nutrients (Dusterhoft and Voragen, 1991). However, fibre in palm kernel cake is degraded to the smallerunits of sugar, mostly mannose it has been suggested that the absorption ofmannose is much lower than glucose, particularly when glucose is present in thesystem (Saenphoom et al., 2013). The addition of enzymesto palm kernel cake and its effect on nutrient content analysis (Chong etal., 2008 and Saenphoom et al., 2011), nutrient digestibilitytrial (Sekoni et al.
, 2008; Ao etal., 2011). However, using fibrolyticenzymes as a biological treatment for palm kernel cake diets was reduced thefibre content and the increase of the total sugar released and there was animprovement in the metabolic energy value (Chong et al., 2008;Soltan, 2009; Saenphoom et al., 2011 and 2013). The effect ofproductive performance of different classes of livestock such as pig (Ao etal.
, 2011), layers (Chong et al., 2008), fish (Ng and Chong,2006), broiler chickens (Soltan, 2009) have been evaluated. While,the studies of usingenzymes to palm kernel cake for ruminants was poor. The composition of NDF, ADF, cellulose and hemicellulose contentsof enzyme treated palm kernel cake was significantly decreased (Saenphoom etal., 2011). Various studies have been reportedto enhance nutrients digestibility and nutritive values of palm kernel cakethrough solid-state fermentation either by using fungi such as Sclerotium rolfsii,Trichoderma harzianum (Ramin et al., 2010), Aspergillusniger (Iluyemi et al., 2006; Ramin et al.
, 2010; Lawal etal., 2010), Trichoderma longibrachiatum and Trichodermakoningii (Iluyemi et al., 2006), Trichoderma varidae andMucor mucedo (Lawal et al., 2010), Rhizopus spp.(Rahim et al.
, 2007; Lawal et al., 2010; Ramin et al.,2010), and bacteria such as Bacillus 7DY7 (Wong et al.,2010).
Forming palm kernel cake under sold statefermentation conditions have been reported to be more proper for low purpose,and there is no any waste disposal at the end because the whole product may beused directly in animal feeds. Also, sold state fermentation of palm kernelcake produces a product that contains low hemicellulose and cellulose contentsand high protein concentration. The levels of saturated fatty acids decreasewhile unsaturated fatty acids increase as a result of sold state fermentationof palm kernel cake using fungi as culturing agents (Iluyemi et al., 2006).
Feed intake and digestibility: There is a linear decrease in dry matter intake was observed due tothe lower palatability and higher fiber content of the palm kernel cake (Abouheif et al., 1999). Neutral detergent fiber (NDF) intake by the animals showed anegative effect on nutritive value and digestibilities (Tipu et al., 2014). Palm kernel cake expeller, rather thansolvent extracted palm kernel cake is used as a source of protein, energy andfibre for dairy cattle at levels 300–500 g/kg of total diet (Wan Zahari& Alimon, 2004).
However, using palm kernel cake at level 400 g/kg DMhas been associated with reduced concentrate feed intake due to palatabilityproblems (Van Wyngaard, et al. 2015). While, increasing levels ofsolvent extracted palm kernel cake (50, 100, and 150 g/kg DM) in a total mixedration have been found not affect cow dry matter intake, (Carvalho et al.,2006). Dry matter, crude protein and NDFdigestibilities were lower (p<0.05) in buffalo calves fed diet contain 30%palm kernel cake than those fed other diets contain low level of palm kernelcake. The reason behind low digestibility diet 30% palm kernel cake was due toincreased amount of NDF in feed (Islam et al., 2000; Barbosa et al.
,2010; Tipu et al., 2014). The other reason to low digestibility fordiet contain palm kernel cake may also undergo Maillard reaction (the reactionof mannose with amino groups leading to the formation of a brown complex) dueto heat applied in the process before and during oil extraction and this mayadversely affect the digestibility (Sundu and Dingle, 2003; Tipu et al.,2014). Digestibility coefficients for expeller pressed palm kernel cakewere 70.0% for dry matter, 63% for crude protein, 53.0% for neutral detergentfibre (NDF), 52.
0% for acid-detergent fibre (ADF), and 88% for gross energywere obtained using sheep (Suparjo and Rahman, 1987). While, The digestibility coefficients of solvent extracted palmkernel cake was determined by using cattle at 65.1% for dry matter, 72.7% fororganic matter, 69.7% for crude protein and 86.7% for the nitrogen free extractcomponent (Miyashige et al.
1987). Effect of feeding palm kernel cake on dairycattleFeeds is important factors affecting on milkproduction and animal performance which, constitutes about 70 % of the totalcost of enterprises. Therefore, using agro-industrial by-products are veryimportant to minimize the cost of feeds by including cheaper source of energyand protein without any adverse effect on animal productivity.
Palm kernel cakeplays a significant role in utilization has effectively reduced the cost ofmilk production as a result of replace expensive conventional feedstuffs, suchas cotton seed cake, soybean meal with a more economical and locally availableone that also meets the nutrient requirements of livestock. Palmkernel expeller is a low cost by-product and high fibre, it has been usedextensively as a feed by the dairy cattle at 56% (Virah-Sawmy, 2014).Using palm solventextracted kernel cake at levels (50, 100, and 150 g/kg DM) ina concentrate feed mixture have been found not to affect cow milk yield andcomposition (Carvalho et al., 2006). Moreover, milk yield andcomposition (except milk lactose) were not affected in a study in which cowsgrazed high quality pasture in spring season, added with two levels of palm kernel cake (200 and400 g/kg DM) in total mixed ration (Van Wyngaard et al., 2015).
While, supplementationof palm kernel cake may induce a positive milk yield and composition responsewhen the nutrient supply of a pasture-based system is at suboptimum levels (Vander Colf et al., 2015). The high neutral detergent fibre content of palmkernel cake may induce a positive milk fat content response Zebeli et al.(2008). Comparative between the use ofexpeller pressed palm kernel cake and solvent extracted palm kernel cake forfed cows on milk production, it was found out that pressed palm kernel cakegave significantly lower (4.8 kg milk/day) milk production than the solventextracted palm kernel cake (7.9 kg milk /day).
In the same trial, whenSahiwal-Friesian cow were fed on expeller pressed palm kernel cake and solventextracted palm kernel cake lead to a low fat content of 7% (Yusoff et al.1987). Other study found, there are no significant differenceon daily milk yield between cow Sahiwal-Friesian cows fed on conventionalconcentrate feed mixture without palm kernel cake (8.4 kg milk / day) and thosefed on identical amounts of solvent extracted palm kernel cake (7.7 kg milk /day) (Ganabathi, 1983)