Biofuel co-products as livestock feed - Opportunities and challenges

Use of Pongamia glabra (karanj) and Azadirachta indica (neem) seed cakes for feeding livestock 391histopathological changes in the liver at a higher level ofinclusion (16.8 percent w/w) of SKC. Mild degenerativechanges were noticed in the form of cloudy swelling inthe liver of chicks fed a diet containing a mixture of agroindustrialco-products having 63 percent SKC replacing29 percent of a standard diet on an iso nitrogenous basis(Haque et al., 1996). The liver and pancreas of chicksreceiving 2 percent karanj oil and 20 percent EKC in the dietshowed necrosis, fatty changes and disrupted structures(Natanam, Kadirvel and Ravi, 1989). Pathological studiesshowed no remarkable gross changes in vital organs atlower levels of inclusion (i.e. at 20 percent replacement ofred til cake) of SKC (4.45 kg in 100 kg of feed) in the diet ofJapanese quail, but higher levels of inclusion induced minorpathological changes in liver, heart, kidney and lungs (Dharaet al., 1997). Dietary incorporation of either processed orunprocessed karanj cake beyond a 25 percent replacement(6.43 percent in diet) level, except for NaOH-treatedSKC (12.86 percent in diet), resulted in histopathologicalabnormalities and the severity increased with increase inthe level of replacement (Panda et al., 2008). The severityof lesions was comparatively higher in the group fed adiet incorporating 25.72 percent NaOH (2 percent)-treatedEKC. Livers showed hepatic degeneration, with distortion;kidneys showed tubular degeneration with necrotic lesions;spleen cells showed degeneration with necrotic foci anddepletion of lymphocytes; and testes had degenerativechanges of testicular follicles and vaculation. Feeding ofSKC after treatment with either NaOH or Ca(OH) 2 wasfound to be beneficial instead of feeding SKC as such, sinceuntrated SKC induced more severe histopathological lesionsin the vital organs of broiler chickens. Treating SKC with1.5 percent NaOH effectively minimized the toxic effectsof karanjin.The results from different laboratories confirm that EKCas such is unsuitable for poultry feeding. However, afterdetoxification with alkali (2 percent NaOH, w/w) it can beincorporated, but only at a low level (3.24 percent in diet),replacing 6.25 percent of the N moiety of SBM for broilerdiets without adversely affecting performance. However,SKC can be incorporated after alkali (1.5 percent NaOH,w/w) processing at an enhanced level of 6.43 percent inthe diet, replacing 12.5 percent of SBM N, in broiler dietsup to 4-weeks old, beyond which the observed growthdepression on this diet could be alleviated by 0.2 percentmethionine supplementation. Such a diet, by partially substitutingfor the costly and scarce conventional oil cake,can support optimum nutritional performance in broilerchickens. However, further research should be focused ondeveloping improved methods for detoxification to reducethe bitterness and toxic factors in karanj cake, permittingits inclusion at a higher level, making poultry productionmore economic.NEEM SEED CAKENeem oil and other products of the neem tree are usedtraditionally for making cosmetics (soaps, mild detergents,creams, teeth cleansers) and traditional Indian medicines(for skin infections, inflammations, fever, leprosy, malaria,tuberculosis, worm infestation, eczema, etc.), in additionto being a source of anti-bacterial and anti-fungal agentsin bio-manure and plant protection. In 1995, the EuropeanPatent Office granted a patent on neem as an anti-fungalagent to the United States Department of Agricultureand multinational company W.R. Grace, to which theGovernment of India objected, as neem has been used asan anti-microbial agent for more than 2000 years. This wasdecided in favour of India in 2000, but when the multinationalmounted an appeal, it took five more years beforedismissal of the appeal, in March 2005.Distribution of the neem treeNeem or margosa (Azadirachta indica; syn. Melia azadirachtaLinn.) is a fast growing evergreen perennial treewith a height up to 20 m, and belongs to the familyMaliaceae. It is found widely in semi-arid to sub-humidareas of the tropics, but it can thrive well even in warm,dry arid regions having rainfall less than 500 mm annually.Though neem is native to India, it has spread to Pakistan,Bangladesh, Sri Lanka, Malayasia, Indonesia, Thailand andthe Near East. In Africa, it was introduced by Indian settlersand is abundant in the whole tropical belt from Eastto West Africa. Neem is also reported to occur in the WestIndies Islands and some countries of Central and SouthAmerica (Anon., 1948). Neem can grow in a wide rangeof climatic conditions. Such a wide adaptation and toleranceto varied soil and climatic conditions confirms its highdegree of heterozygosity and potential scope for increasingproduction through selection, if the nutritional worth of itsco-products are proved and found safe for feeding. Indiahas about 25 million neem trees, with an average annualproduction potential of 900 000 tonne of neem seed cake(NSC) as a residue after oil extraction (Singh, 1993).Bitter and toxic neem compoundsNeem seed kernel cake, a protein rich (35–40 percent CP)agro-industrial co-product hitherto utilized as fertilizer-cumpesticide,was found unsuitable for animal feeding due topresence of bitter and toxic triterpenoids (azadirachtin,salanin, nimbin, nimbidiol, etc.). The bitterness of neemis attributed to limonoids, which are the triterpenoids.The pioneer work of Siddiqui (1942) revealed that the bitterprinciples (1.2 percent of dry matter) comprised bothwater- and fat-soluble fractions. The main feature of thesecompounds is that they are mostly tri- or tetra terpenoids.The structure and chemistry of these compounds hasrecently been reviewed by Devakumar and Dev (1993),