Phosphorus metabolism and its availability in ruminant diets

The current study aimed to improve the utilization of phosphorus from different feedstuffs that contain high levels of phytate phosphorus (undecorticated cottonseed meal, wheat bran, rice bran and the concentrate feed mixture) by adding different levels of phytase enzyme (0, 500, 1000, 1500 and 2000 IU/ Kg DM). Many experiments were carried out to evaluate the effects of phytase supplementation on in vitro degradation of ingredients, in vivo performance of growing animal's and nutrients digestibility coefficients, nutritive values, rumen parameters, nitrogen retention, Ca and P balances by mature Rahmani sheep. Phytase supplementation significantly improved final body weight, total body gain, average daily gain, feed conversion ratio, P and Ca balances and blood contents of P and Ca. These results indicate that phytase supplementation to growing lamb rations improve their performance, increased phosphorus bioavailability and decreased fecal phosphorus excretion in those animals.