Biofuel co-products as livestock feed - Opportunities and challenges

358Biofuel co-products as livestock feed – Opportunities and challengesTABLE 5Amino acid composition (g/16 g nitrogen) of kernel meals of Jatropha curcas (toxic and non-toxic genotypes),J. platyphylla and SBM, versus FAO reference dietary protein requirement valuesAmino acidJatropha curcasToxicNon-toxicJ. platyphylla SBMFAO reference protein(2–5-year-old child)EssentialMethionine 1.56–1.91 1.38–1.76 1.58 1.32Cystine 1.77–2.24 1.58–1.81 1.55 1.382.50 (1)Valine 4.35–5.19 3.79–5.30 6.91 4.50 3.50Isoleucine 3.93–4.53 3.08–4.85 4.10 4.16 2.80Leucine 6.55–6.94 5.92–7.50 6.68 7.58 6.60Phenylalanine 4.08–4.34 3.93–4.89 4.71 5.16Tyrosine 2.45–2.99 2.62–3.78 2.69 3.356.30 (2)Histidine 2.81–3.30 2.65–3.08 2.66 3.06 1.90Lysine 3.63–4.28 3.40–3.49 3.16 6.18 5.80Threonine 3.33–3.96 3.15–3.59 3.64 3.78 3.40Tryptophan 1.31 ND 1.06 1.36 1.10Non-essentialSerine 4.67–4.80 4.59–4.91 5.05 5.18 –Arginine 11.8–12.2 11.4–12.90 12.46 7.64 –Glutamic acid 14.68–16.7 15.91–16.50 16.21 19.92 –Aspartic acid 9.49–11.8 9.92–11.7 9.33 14.14 –Proline 4.13–4.96 3.80–4.21 5.16 5.99 –Glycine 4.40–4.92 4.18–4.61 4.56 4.52 –Alanine 4.36–5.21 4.26–4.94 4.04 4.54 –Notes: (1) Methionine plus cystine; (2) Phenylalanine plus tyrosine. ND = not detected. Sources: Makkar and Becker, 2009a; Makkar et al., 2011.TABLE 6Pepsin plus trypsin digestibilities, available lysine, digestible organic matter, metabolizable energy and rumen-degradablenitrogen of heat-treated jatropha kernel mealsJatropha curcasToxic Non-toxicJatrophaplatyphyllaSBMPepsin plus trypsin digestibility (% of total nitrogen) 89 90 97.1 91Available lysine (mg/100 mg sample) 3.10 3.16 3.29 –Available lysine (g/16 g N) 4.87 5.06 4.95 –Digestible organic matter (%) 78 77.3 – 87.9Metabolizable energy (MJ/kg) 10.9 10.7 – 13.324-hour in vitro rumen-degradable nitrogen (% of total nitrogen) 43.3 28.9 – 80.9Notes: SBM = Soybean meal. Sources: Makkar and Becker, 2009a; Makkar et al., 2011.defatted kernel meal obtained from J. curcas genotypes(toxic and non-toxic) and these are listed in Table 7.Phorbol esters are naturally-occurring compounds thatare widely distributed in plant species in the Euphorbiaceaeand Thymelaeceae. They are tetracyclic diterpenoids ofphorbol type and esters of tigliane diterpenes (Evans,1986; Devappa, Makkar and Becker, 2010b, 2011a). Sixphorbol esters (jatropha factors C1–C6) have been characterizedfrom J. curcas seed oil (Haas, Sterk and Mittelbach,2002; Devappa, Makkar and Becker, 2010b, 2011a) anddesignated as C1 (A), C2 (B), C3 (C), epimers C4 (D), C5(E) and C6 (F), with the molecular formula C 44 H 54 O 8 Na(MW 733.37) (Figure 2). The phorbol esters are lipophilic,present mainly in oil or kernel, and are not affected by heattreatment. The concentration of phorbol esters varies from1 to 3 mg/g kernel meal and from 2 to 7 mg/g oil (Makkarand Becker, 1997, 2009a; Devappa, Makkar and Becker,2010b, 2011a). Table 8 shows phorbol ester content ofdifferent parts of a toxic J. curcas plant. Figure 3 representsthe phorbol ester content in different part of the toxicJ. curcas kernel (Devappa, Makkar and Becker, 2011b).Rumen microbes cannot degrade phorbol esters(Makkar and Becker, 2010b) and they cause as severe toxicsymptoms in ruminants as they do in monogastric animals.These mimic the action of diacylglycerol, an activator ofprotein kinase C which regulates different signal transductionpathways (Devappa, Makkar and Becker, 2010a, b,2011a). Phorbol esters affect a number of processesincluding phospholipid and protein synthesis, enzymeactivities, DNA synthesis, phosphorylation of proteins, celldifferentiation and gene expression. These are consideredto be a co-carcinogen and have strong purgative andmembrane-irritant effects (Goel et al., 2007; Devappa,Makkar and Becker, 2010a, b, 2011a).