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- Title
309 Empirical Calibration of Ideal SID Isoleucine to Lysine Profile in Growing Pigs (70-102 kg BW).
- Authors
Zier-Rush, C E; Haydon, K D; Elsbernd, A J; Rosero, D S; Boyd, R D
- Abstract
The ideal profile for standard ileal digestible (SID) isoleucine is not known with confidence. The NRC (2012) estimated, through factorial calculation, the SID isoleucine (ILE) profile to be 53% that of lysine (LYS) for 70 kg pigs. An empirical estimate was determined to be 60-62% at asymptote for 90 kg pigs, depending on criterion (D. Kendall, Ph D Dissertation, 2004). Our study was conducted to calibrate the NRC estimate for SID ILE profile in 70-100 kg pigs, so that amino acid (AA) displacement of SBM is not compromised by a deficit ILE level. A total of 1928 PIC terminal (TR-4 x Camborough) castrate and female pigs (70.9 ± 0.7 kg) were used in a 35 d growth assay to 102.4 kg (±0.9 kg). Pigs were placed in a commercial research facility, blocked by sex and weight then allocated (19 pigs/pen, with 0.78 m2/pig) to treatment. Treatments were arranged as a 2 x 5 factorial, involving sex and 5 ILE:LYS (SID) ratio's (0.50, 0.56, 0.62, 0.68, 0.74). Pen was the experimental unit (10 pens/diet x sex subclass). Diets were composed of corn, soybean meal, choice white grease (1.5%) and AA. Two diets were milled and summit blended to create three additional diets using the Howeema system. Diets were isocaloric with SID LYS:Mcal NE set to approx. 96% asymptote, based on internal whole-body gain and G:F response curves: 2.684 and 2.301 g SID LYS:Mcal NE from 70 to 90 kg and 90-102 kg respectively. Ratio to LYS for key AA met or exceeded NRC minimums: Thr, 0.68, Trp, 0.22, Met, 0.32, Met:Cys, 0.58, Val, 0.68. The SID LYS:CP ratio ranged from 0.0588 to 0.0603. Average daily feed intake was not affected by diet (P=0.86) and sex x diet was not significant (P>0.50). The G:F response to ILE:LYS ratio was quadratic (0.329, 0.336, 0.338, 0.339, 0.323, SEM ±0.005, P<0.01) and described as: Y= -0.0135 + 0.0117x - 0.00010x2 (R2=0.34, P<0.01). Average daily gain also responded in quadratic manner (0.904, 0.916, 0.924, 0.910, 0.887 kg/d, SEM ± 0.013, P=0.07); being represented as: Y= 9.1546 + 0.7682x - 0.00638x2 (R2=0.16, P=0.06). Growth-derived estimates for ILE:LYS (SID), at asymptote, were 0.61 and 0.60 for G:F and total gain, respectively. This exceeds the NRC estimate for the 70-100 kg pig and illustrates the importance of empirical calibration of ideal AA patterns.
- Subjects
SWINE growth; LYSINE in animal nutrition; DIGESTION; SWINE nutrition; ILEUM physiology; ISOLEUCINE; SWINE
- Publication
Journal of Animal Science, 2018, Vol 96, p166
- ISSN
0021-8812
- Publication type
Article
- DOI
10.1093/jas/sky073.306