Phosphorus digestibility in low-phytate barley fed to finishing pigs

Abstract

Thacker, P. A., Rossnagel, B. G. and Raboy, V. 2003. Phosphorus digestibility in low-phytate barley fed to finishing pigs. Can. J. Anim. Sci. 83: 101-104. Twenty-four crossbred barrows (Camborough 15 Line female × Canabred sire) weighing an average of 51.3 ± 5.1 kg were used in a trial conducted during two periods according to a completely randomized block design. The pigs were assigned to one of six dietary treatments comprised of a normal two-rowed, hulled variety of barley (CDC Bold) or three low-phytate genotypes selected to contain approximately 68, 41 or 3% of the normal level of phytate. A normal hulless barley (CDC Dawn) and a hulless genotype selected to contain 54% of the normal phytate content were also included. The diets fed contained 99.5% barley and 0.5% chromic oxide. The marked feed was provided for a 7-d acclimatization period, followed by a 3-d fecal collection. At the conclusion of the first replicate, the pigs were assigned to different treatments and the procedure was repeated resulting in eight observations per treatment. Selection for phytate content had no effects on the apparent fecal digestibility of dry matter, crude protein or gross energy (P > 0.05). The digestibility coefficients for dry matter and energy were significantly higher for the hulless varieties of barley than the hulled genotypes. Phosphorus digestibility increased as the level of phytate in the barley declined. The linear relationship relating phosphorus digestibility (y) to phytate content (x) was: y = 67.7 -12.54x (r 2 = 0.64; P < 0.0001).Increasing the availability of the phosphorus in barley would allow less inorganic phosphorus to be required in order to meet the nutritional requirements of swine. Since inorganic phosphorus sources tend to be expensive, a reduction in their use would lower ration costs. In addition, increased availability of organic phosphorus would reduce the amount of phosphorus excreted thus reducing the amount of phosphorus that can potentially pollute the environment. Les animaux ont d'abord reçu les aliments marqués pendant sept jours pour s'y adapter puis on a recueilli leurs fèces trois jours durant. À la fin du premier essai, on a servi aux porcs l'une des différentes rations et répété l'expérience, pour un total de huit observations par traitement. La concentration de phytate n'a aucune incidence sur la digestibilité apparente de la matière sèche, des protéines brutes et de l'énergie brute dans les fèces (P > 0,05). Le coefficient de digestibilité de la matière sèche et celui de l'énergie sont significativement plus élevés pour les variétés d'orge nue que pour les génotypes avec balle. La digestibilité du phosphore (y) augmente avec la baisse de la concentration de phytate (x) dans l'orge, la relation linéaire entre ces deux facteurs étant la suivante : y = 67,7 -12,54 x (r 2 = 0,64; P < 0,0001).En facilitant l'assimilation du phosphore présent dans l'orge, on réduirait la quantité de phosphore minéral qu'il faut ajouter à la ration pour répondre aux besoins nutritifs de l'animal. Les so...

Phosphorus utilization and characterization of excreta from swine fed diets containing a variety of cereal grains balanced for total phosphorus1

“…Thacker et al (2003) reported DM digestibility coefficients of 0.77 and 0.74 when swine were fed normal-and low-phytate barley diets, respectively, and were similar to the values obtained for these treatments in the present study. Bruce and Sundstøl (1995) reported a DM digestibility coefficient for oat-based diets of 0.76, which is similar to the value of 0.74 obtained in the present study.…”

“…This is likely due to the inclusion of supplemental dicalcium phosphate in the present study, which would have greater bioavailability than when P is supplied by grain alone. Thacker et al (2003) reported a P digestibility coefficient of 0.39 when swine were fed a low-phytate barley diet, which was less than the value of 0.45 obtained in the present study. The low-phytate barley had a greater apparent P digestibility coefficient than the other dietary treatments, which was expected because this diet contained little phytate and thus would have a greater available P concentration.…”

Nutrient digestibility in diets containing low-phytate barley, low-phytate field pea and normal-phytate field pea, and the effects of microbial phytase on energy and nutrient digestibility in the low and normal-phytate field pea fed to pigs

“…Studies with low-phytate cereals have reported improved P and AA digestibilities when fed to pigs and poultry or compared to normal phytate varieties (Spencer et al, 2000;Thacker et al, 2003Thacker et al, , 2004Bohlke et al, 2005). Recently, a low-phytate field pea (LPP) with 0.09 mg/kg phytate P content compared with a 2.9 mg/kg phytate P content in normal field pea (NPP) has been developed (Delgerjav et al, 2011).…”

“…Barley and pea are common ingredients included in diets fed to nonruminant animals in western Canada (Thacker et al, 2003;Friesen et al, 2006). However, they are poor sources of phosphorus (P) because 60-80 g/100 g P is bound as phytate P, a form that is largely undigested by nonruminants (Veum et al, 2002).…”

The effect of feeding low-phytate hulless barley-soyabean meal diets differing in protein content to growing pigs on phosphorus and nitrogen excretion

“…The LPHB diets contained less SBM than the HB diets (Table 1) and the availability of P in SBM is lower than in barley (Cromwell, 2003). Thacker et al (2003Thacker et al ( , 2004) also reported that the ATTD of P in finishing pigs fed a LPHB diet was higher than in pigs fed a HB diet. Although the ATTD and retention of P were higher, the amount of P retained was lower for pigs fed the LPHB than the HB diets.…”