Conventional agro-industrial oilseed cakes
Groundnut meal: It is readily available protein source byproduct from the extraction of groundnut, which is a popular human food in many part of the world. Its availability in India is about 5.7 MMT annually. The nutrient composition of the meal varies greatly according to the oil extraction method used. It is quite palatable and contains 44% crude protein and 78% TDN. The quantity of hulls present directly affects fibre and therefore energy content of the meal. Extracted groundnut meal generally has less than 1.5% fat. The fat content of expeller groundnut meal is variable depending on the efficiency of oil extraction. With prolonged storage under the warm and humid conditions in the tropics, residual oil is a negative feature as it is easily oxidized. The meal quality is then greatly reduced due to poor palatability, toxicity and decreased energy value. The undesirable constituent often associated with groundnut meal is mycotoxins especially aflatoxins produced by the fungus Aspergillus parasiticus and A. flavus that infests groundnuts before, during and after harvest.
Cottonseed meal: It ranks third among the total oilseed meals produced in the world. Total production in 2000 was 14.9 MMT. Typical yield from whole cottonseeds are 50% meal, 22% hull and 16% oil. When compared to soybean meal, cottonseed meal has a slightly lower protein of about 40% but a much higher fibre content of 11- 13%. The TDN content is about 75-78%. Depending on the processing method employed, the energy content is influenced by the residual oil present in the meal. Digestibility of the amino acids in cottonseed meal is lower than that found in soybean meal. Decortications and delinting cottonseed makes the meal more nutritious and incorporation higher levels in feed formulation. Gossypol is recognized toxic component of cottonseed meal limiting its use in mono-gastric animals. Gossypol further limits the total amount of cottonseed products in diets to 3-4 kg per day per animal in case of ruminants or less.
Sunflower meals and heads: Total world production of sunflower meal was 10.7 MMT in 2000. The nutrient composition of sunflower meal varies according to the quality of the seed and methods used for oil extraction. The quality also depends on whether or not the seeds are dehulled prior to oil extraction. Dehulled sunflower meal can have protein content in excess of 40% and crude fibre of 13% or less. Partial dehulling produces meals of 30 to 35 % protein whereas whole sunflower meal has about 25% crude protein. The TDN content is about 66%. The crude fibre of partially dehulled or non-hulled sunflower meal exceeds 20%. Unlike soybean meal, sunflower meal is high in methionine but low in lysine and threonine. Therefore the two ingredients, when used together, improve the amino acid balance of the feed. Sunflower meal is not recommended for use in high nutrient density feeds because of its high fibre and low energy content. Sunflower heads (SFH) after removal of seeds are either burnt in the fuel or dumped on wayside, though nutritionally far superior to many of the conventional roughages like paddy straw, wheat straw etc.
Soybean meal: Soybean meal is an excellent source of CP and fat (18 %) for dairy cattle. Raw soybeans can be fed up to 2.5 kg per cow per day. Cows should be adjusted to beans gradually to avoid diarrhea and off-feed. Raw beans contain urease, an enzyme that release ammonia from urea when soybeans and urea are mixed together. Urea and raw beans should not be mixed and stored together. Microbial degradation in the rumen reduces anti-protein factors in raw beans (e.g. trypsin inhibitor). Roasting, extruding, or other heat processing reduces anti-protein factors and urease activity and increases UDP value of the soybeans. Heating temperature (290 to 300 degrees F) and steeping time (30 to 45 minutes) must be carefully controlled to avoid under or over heating soybeans. Heat treated soybeans can be fed upto 3-4 kg per day. Soybean meal is the most common and usually the most economical vegetable protein supplement. The most common soybean meal contains 44 % CP as fed. Two other sources of soybean meal are dehulled soybean meal 48 % CP) and expeller or old processed soybean meal (42 % CP and 5 % fat). Soybean meal is produced mainly in Madhya Pradesh and some part of Gujarat, Rajasthan and Maharashtra. It contains about 52-53% crude protein and 80% total digestible nutrients (TDN).
Rapeseed meal: It ranks second to soybean meal in terms of total world production of protein meals. Rapeseed meal is available to extent of 5.40 MMT in India. It has high levels of glucosinolates, erucic acid and other anti-nutritional factors. It contains about 38% crude protein and 68-70% TDN. Rapeseed meal is usually incorporated in compounded cattle feed @ 5-25 %, based on regional feeding practices. The quality of rapeseed meal is influenced by the varieties of rapeseed used for oil extraction and the method of extraction process. The optimum temperature for conditioning ranges from 100 to 105 oC for a duration of 15-20 minutes. Myrosinase, which converts glucosinolates to the goitrogenic and ‘hot’ tasting compounds: oxazolidone-2-thione and isothiocyanate.
Castor cake: The production of castor seeds has increased by five folds in the last three decades as the castor seed contain about 35 to 40% of oil. It is estimated that about 550 thousand tones of castor cake is available in India. The major limiting factor in utilization of castor cake is the presence of ricin, an anti-nutritional factor.Lime treatment followed by extrusion cooking has been proved to be the most effective detoxification method. Inclusion of 10% castor cake in the concentrate mixture of lactating buffaloes has economic advantage without adversely affecting feed intake, nutrient utilization, milk yield and general health. The destruction of ricin toxicity by heat has long been recognized. The presence of more than one toxic principle which differs in heat resistance in castor beans must be taken into account when working with products derived from these seeds. The studies suggest that castor meal processed either by autoclaving or cooking with water can be included as protein source in broiler diets up to 2.5% level without adversely affecting the performance and general health status of birds.
Copra meal: It is obtained from the kernel of coconut fruit, which has been sun dried or dried using drying machines. From the copra, about 65 to 69% by weight is extracted as coconut oil. Copra cake produced by the expeller process has a residual oil content of about 8% to 10%. This is reduced further by solvent extraction depending on the market demand for oil, which at the present time is quite high. Copra meal after solvent extraction has about 24% protein for ruminants. It is also said that quality of butter improves with incorporation of copra meal in feed formulations of milch animal. Higher fines in copra cake, presence of coconut flakes of the endocarp from desiccated coconut make processing more difficult due to imbalanced presence of oil content in the copra cake. Presence of shell pieces also could cause problems to cattle if they are not fully removed at the time of coconut deshelling. Similarly type of drying of copra also has a bearing on the quality of copra cake.