The effects of phytase supplementation and available lysine content of weaner diets on pig growth performance.

Abstract

10A 10A The effects of phytase supplementation and available lysine content of weaner diets on pig growth performance D.J. Cadogan1, P.H. Selle2 and R.G. Campbell 1Bunge 1 Meat Industries, Corowa NSW 2646; 2BASF Animal Nutrition, Auburn NSW 2144 Microbial phytase supplementation of phosphorus adequate weaner diets has improved growth performance (Campbell et al. 1995) and responses in feed conversion have increased with dietary substrate concentrations of phytateP or phytic acid (Cadogan et al. 1997). The release of phytate bound amino acids by the enzyme may improve protein digestibility (Officer and Batterham 1992) and, consequently, feed efficiency. To investigate this hypothesis 14.8 MJ/kg DE wheatbased diets were formulated to contain three levels of available lysine (0.90, 0.85 and 0.80 g/MJ DE) with and without phytase (0 and 550 FTU/kg; Natuphos� Granulate). The nonsupplemented diets contained 0.89% Ca and 0.49% available P; these levels were reduced to 0.77% and 0.37% respectively with added phytase. The pelleted (75�C) diets had substrate levels of 0.24% phytateP with Ca:P ratios of 1.25:1. The six dietary treatments were of fered to 72 individually housed male pigs from weaning (6.0 kg liveweight at 26 days of age) and their performance was recorded over a feeding period of 21 days. The results are presented in Table 1. Phytase improved (P <0.01) feed efficiency with a trend (P <0.10) towards increased growth rates. Unexpectedly, lysine levels did not have any significant effects on performance, possibly because essential amino acids were in excess of requirements.At the lowest lysine level, phytase significantly improved feed efficiency which may be related to increased protein and/or energy availability because phytase increased the digestibility of all three diets regardless of their essential amino acid content. The antinutritive properties of phytic acid (and excess Ca and P) and the response of weaner pigs to added phytase is again demonstrated in this study. Cadogan, D.J. Selle, P.H. Campbell, R.G. and Walker, A.R. (1997). Effects of dietary phytate phosphorus and microbial phytase on the performance of weaner pigs. In: Manipulating Pig Production VI, p. 245 (ed. P.D. Cranwell). Australasian Pig Science Association, Werribee Vic 3030. Campbell, R.G. Harrison, D.T. Butler, K.J. and Selle, P.H. (1995). Effects of dietary available phosphorus and phytase (Natuphos) on the performance of pigs from 19 to 40 days postweaning. In: Manipulating Pig Production V, p. 193 (eds. D.P. Hennessy and P.D. Cranwell). Australasian Pig Science Association, Werribee Vic 3030. Officer, D.I. and Batterham, E.S. (1992). Enzyme supplementation of Linola� meal for grower pigs. Proceedings of the Australian Society of Animal Production 9, 288. Table 1 Effects of phytase and lysine on the performance of male pigs for 21 days post_weaning. Available lysine (g avail lys/MJ DE) 0.90 0.90 0.85 0.85 0.80 0.80 Microbial phytase (MP) Available lysine (AL) Interaction (MP x AL) Performance Daily gain (g) 361 437 373 359 353 393 0.072 0.329 0.154 Feed intake (g/day) 427 489 436 398 437 446 0.592 0.385 0.165 Feed:Gain Treatments Microbial phytase (FTU/kg) 0 550 0 550 0 550 Probability (P =): 1.18 ab 1.13 b 1.17 ab 1.11 b 1.24 a 1.14 b 0.009 0.294 0.777 a,b P <0.05 Recent Advances in Animal Nutrition in Australia, Volume 12 (1999)