Bioavailability of minerals in feedstuffs
1983
Hutagalung, R.I. | Cromwell, G.L. (Universiti Pertanian Malaysia, Serdang, Selangor (Malaysia). Dept. of Animal Sciences)
Very little is known on the availability of calcium in feedstuffs of plant origin, presumably because to these ingredients contribute such small amounts of calcium (Ca) to the total diet that any variation in biological availability is probably of little significance. On the other hand, about 50 percent or more of the dietary phosphorus (P) is derived from cereal grains and plant-protein sources. Hence, studies were carried out to measure Ca availability in various major Ca sources and available P in cereal grains, plant protein sources and by-product ingredients. Results from trials in pigs and chicks indicate that calcium was highly available in limestone (of differing particle size), gypsum (calcium sulfate) and ground oyster shell, less available in marble and in dolomitic limestone and poorly available in soft rock phosphate. Dicalcium phosphate, deflourinated rock phosphate and steamed bone meal are nearly the same in P availability, while Curacao phosphate and soft rock phosphate appear to be low in P availability. High Ca and P availability is observed in meat and bone meal. Fish meal products appear to have large variation in available Ca and P, mainly due to improper processing methods. Using slope-ration techniques of bone breaking strength of young animals, corn and barley contain available P of 12 and 51 percent, respectively.
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