The retention of phytin phosphorus from diets with fat supplements in broiler chicks

Abstract

An experiment was conducted to investigate the influence of various fats added to diets on performance and retention of phytin phosphorus, non-phytin P and total P in broiler chicks. Broilers were fed on a wheat and soya-bean meal diet or on the same diet containing 6% beef tallow, 6% animal-vegetable blend fat, or 6% horse tallow. The retention of P was determined in two digestion trials conducted in Weeks 3 and 7 of life using the total collection method. The experiment confirmed the benefical influence of fats on performance of broilers as all three fats significantly improved body weight gain and feed efficiency. The source of fat had no significant effect on body weight gain. However, better feed conversion was observed in broilers given the diets with the animal-vegetable blend fat or horse tallow than in those given the beef tallow supplement ( P < 0.05). The retention of phytin P in 3-week-old chicks was low (5.4%) and significantly increased with the age of birds to 17.3% ( P < 0.001). Retention of this form of P in 3-week-old chicks was reduced to 2.8% ( P < 0.01) by dietary beef tallow, probably by the decline of phytase activity in the presence of saturated fat. The source of added fat had no significant effect on phytin P retention in 7-week-old birds. The retention of non-phytin and total P was influenced more by the age of birds than by source of supplementary fat. Beef tallow, in contrast to unsaturated fats, can be considered as a factor which decreases the utilization of phytin P in 3-week-old chicks.