Published online by Cambridge University Press: 27 March 2009
Cakes derived from Taramira (Eruca sativa), Raya (Brassica juncea), Toria (B. campestris var. toria) and yellow and brown sarson (B. campestris var. sarson) were evaluated for their contents of crude protein, true protein, essential amino acids, available carbohydrate and tannins. Feeding trials were also conducted to compare the suitability of these cakes with groundnut cake for broilers and White Leghorn chicks up to 4 weeks of age.
The crude protein content of Taramira cake was 33% whereas all the other cakes contained 37–38%. True protein accounted for 80–83% of crude protein in all the varieties and albumin and globulin constitutes the bulk of protein. The critical amino acid content of all the brassica seed proteins was found to be higher than that of other vegetable proteins although varietal differences were observed with respect to a few essential amino acids. The hulls accounted for 19% of whole Brassica seed and their removal raised the concentration of protein from 39 to 46% and reduced the crude fibre content from 15 to 6% in the defatted meal. Tannin content was higher in Taramira (1·74%) than in all other varieties (1·0–1·4%) and the major quantity of it was localized in the endosperm. The average metabolizable energy content of all the mustard cakes was 9·62 and 8·75 MJ/kg for meat-type and egg-type chicks, respectively. The nutritive value of Taramira cake was poorer than that of other Brassica cakes or groundnut cake for supporting growth rate of chicks of either breed.