Biofuel co-products as livestock feed - Opportunities and challenges

Use of Pongamia glabra (karanj) and Azadirachta indica (neem) seed cakes for feeding livestock 381TABLE 1Conventional uses of Pongamia glabraPlant partOilLeaf juiceRootsBarkFlowersFruit and seedConventional usesCommonly used as a lubricant, water-paint binder, pesticide, in soap-making, for tanning, as fuelfor cooking and lamps, as medication in rheumatism, for itches, herpes, effective in enhancing thepigmentation of skin affected by leucoderma or scabies.Medicinally for colds, coughs, diarrhoea, dyspepsia, flatulence, gonorrhoea and leprosy, and as ananthelmintic, digestive and laxative aid.Cleaning gums, teeth, and ulcers.Bleeding piles.Biliousness and diabetes.Keratitis, piles, urinary discharges and diseases of the brain, eye, head and skin.Medicinal activity of various products70% ethanolic extract of Anti-inflammatory activity without any side effects; anti-pyretic actionleavesDecoction of leavesAnti-diarrhoeal action.Ethanolic extract of flowers Anti-hyperglycaemic and anti-lipidperoxidatives effects.Sources: Adapted from Chopade et al., 2008; Srinivasan, Muruganandan and Lal, 2001; Brijesh, Daswani and Tetali, 2006; Punitha and Manoharan, 2006.ronments and thrives in areas having an annual rainfall of500–2500 mm. In its natural habitat in India, the maximumtemperature ranges from 27 to 38 °C, with a minimum of1 to 16 °C. Mature trees can withstand waterlogging andslight frost. These trees can grow even at a height of about1200 masl, although in the Himalayan foothills it is notfound above 600 masl (Government of India, 1983).It is known by different names in different Indian languages:‘karanj’ in Hindi, ‘pongam’ and ‘punnai’ in Tamil,‘honge’ in Kannada, ‘Indian beech’ in English, ‘kanuga’ inTelugu and ‘karanja’ in Bengali. It bears compound pinnateleaves consisting of 5–7 leaflets arranged in 2 or 3 pairs.Leaflets are 5–10 cm long, 4–6 cm wide and pointed at thetip. Flowers are borne on racemes, and are pink, light purpleor white in colour. Pods are elliptical, measuring 3–6 cmin length and 2–3 cm in width, with a thick wall and usuallycontaining a single seed. Seeds are 1–2 cm long or oblongand light brown in colour.Karanj thrives on all sorts of soils, ranging from stony,through sandy to clayey, including vertisols, but prefers welldrainedlight porous soil. It is a common sight to find the treenear perennial water sources, on the banks of rivers, streams,tanks, canals and lakes. It is also a well-known avenue tree,grown in parks, gardens and roadsides. It is highly tolerantof salinity and hence it is common along waterways orseashores, with its roots in fresh or salt water. It does not dowell on dry sands, and the highest growth rates are observedon well-drained soils with assured moisture.The tree starts bearing seeds at 4–7 years. The fruitcome to harvest at different periods of the year in differentparts of the country, but the harvest season extends ingeneral from November-December to May-June. The podsare collected and the shells are removed either by hand orseparated by a decorticator before oil extraction. The seedyield ranges from 10 kg to more than 90 kg per tree (Anon.,1969). Mature seed contains 5 percent shell and 95 percentoleaginous kernel. Pressing the seed produces 25 percentoil and 70 percent residue, known as cake, assuming 5 percentof losses. This is a high oil yield compared with otheroil seeds. The main drawback is that the cake is non-edibleas such, due to its toxicity.Karanj seed production in India is 110 000 to130 000 tonne annually (Ministry of Agriculture, 1992;NOVODB, 1995), of which about 85 500 tonne go uncollected.Seeds are mainly used for oil extraction and productionis nearly 30 000 tonne per annum (De et al., 1998). Theoil is dark in colour, with an unpleasant odour. Technologyhas been developed to upgrade oil quality for soap manufactureand other industrial purposes.Different plant parts of the karanj tree have differentuses, and their extracts have medicinal values, as listed inTable 1. The karanj oil has varied uses in industry (leatherdressing, soap making, lubrication, bio-diesel, illumination,etc.), as an insecticide or in medicine. The oil is known for itscurative effect on skin problems, such as leucoderma, psoriasis,scabies and skin itches (Bringi and Mukerjee, 1987). Atpresent, the use of karanj oil for the production of biodiesel isbeing explored (De and Bhattacharyya, 1999; Srivastava andPrasad, 2000; Vivek and Gupta, 2004; Meher et al., 2006).Increased production of biodiesel from karanj may enhancethe availability of karanj cake, which is the residue left afteroil extraction. The cake, which is bitter and pungent, is usedas manure, fungicide or insecticide. Although the cake is aprotein-rich co-product potentially of great value for animalfeeding, it is seldom used in animal feeding due to its poorpalatability and the presence of various toxic constituents.Chemical composition of karanj cakeThree main types of karanj cakes are available, namelyrotary pressed, expeller-pressed (EKC) and solvent-extracted(SKC), the composition of which depends on the degreeof decortication and method of oil extraction. The crudeprotein content of rotary-pressed karanj cake (Natanam,Kadirvel and Balagopal, 1988; Chandrasekaran, Kadiravel