Energy and nutrient digestibility in a hulless low-phytate phosphorus barley fed to finishing pigs

Six-ileal cannulated finishing barrows were used to determine energy and nutrient digestibility in a sample of a hulless low-phytate (LP) barley cultivar. A sample of regular hulled (RH) barley was also included for comparison. Two diets containing 96.5% of either LP or RH barley, 2.5% trace minerals and vitamins and 1% indigestible marker (Celite) were fed in a two period change-over design. Six barrows [(Yorkshire xLandrace) x Duroc] with an initial BW of 59±5 kg and fitted with a T-cannula at the terminal ileum were used in this study. Pigs were housed individually in pens with raised, plastic-covered, woven metal floors and smooth walls in a temperature-controlled room. Three pigs were randomly assigned to each of the two diets in a two-period crossover design. Pigs were weighed at the beginning of the experiment and allowed a daily feed amount equivalent to 4% BW in two equal meals offered at 0800 and 1600 as dry mash. Pigs had unlimited access to water via a low-pressure nipple drinker at all times. Each experimental period lasted 9 d; a 5-d acclimatization period followed by 2d of fecal and 2d of ileal digesta collection. Standardized ileal digestibility (SID) of amino acids (AA) was calculated using published values for ileal endogenous AA losses from our laboratory.

Total phosphorus (as is) was similar in LP and RH; however, LP had lower phytate phosphorus (0.6 vs. 2.3, g/kg) than RH. Apparent digestibility of phosphorus was higher (P<0.01) for LP barley than RH at both ileal (45 vs. 24%) and faecal (55 vs. 32%) levels. Compared with RH, LP had higher (P<0.05) DE and SID contents of all indispensable AA except Phe.

In summary, a hulless low-phytate barley sample fed to finishing pigs had higher digestible phosphorus, energy and AA contents than regular hulled barley, indicating that use of hulless low-phytate barley in swine diets may have ecological benefit.