Ricinus communis

Castor

Useful reference: 75

A plant grown as an annual in temperate zones and as a perennial in the tropics, where it becomes a tree up to 10 m high. Three seeds (also incorrectly called "beans") are encased in a spiny outer hull (or shell). After the seeds have been freed from the hulls by drying or with dehulling machinery, the oil is extracted from them. Castor-oil meal is often called castor pomace. The extracted meal contains about 1% residual oil. Screw-pressed cake has about 6-8% residual oil and double-pressed cake 5-7%.

TOXICITY. Castor seeds and hulls contain toxic components. The principal toxic component is ricin, a protein, but a powerful allergen that is more difficult to inactivate than ricin is also present. The allergen may cause hypersensitivity in humans who have contact with the products, but it seems to cause little harm to animals. The ricin can be destroyed by autoclaving the meal for fifteen minutes at 125 C. If no autoclave is available, the meal is boiled in three times the volume of water for ten minutes, after which the water is discarded and the treatment repeated. The cake is then dried in the open air at 70 -80 C.

USE. Apparently fowl have more resistance to the toxic elements than mammals. Up to 40% detoxified meal has been included in poultry rations. High levels of inclusion have also been reported in rations for ruminants; however, it has been recommended that castor pomace be restricted to 5% and hulls to below 10% of the total ration for ruminants. Heifers experimentally trained to consume 0.7 kg of untreated castor meal per day are reported to have shown no ill effects or decrease in appetite.

					As % of dry matter
				DM	CP	CF	Ash	EE	NFE	Ca	P	Ref
Oil meal, prepress-
ed, solvent extr-
acted, USA				92.0	38.5	32.3	7.1	1.0	21.1	0.76	0.87	75
Hulls, USA				91.9	28.8	31.3	7.0	2.2	30.7	0.54	0.65	"
							Digestibility (%)
					Animal		CP	CF	EE	NFE	ME	Ref
Oilcake					Sheep		80.8	8.9	92.9	43.4	1.85	512
		Amino acid composition as % of crude protein
Oilcake											Ref	304
Arg	Cys	Gly	His	Ils	Leu	Lys	Met	Phe	Thr	Try	Tyr	Val
10.0	-	-	1.7	5.3	6.4	3.0	1.5	4.7	3.2	1.1	2.9	5.4