Combining the dietary inclusion of 25(OH)D3 and phytase on pig performance and pork quality

The supplementation of phytase and 25-hydroxyvitamin D₃ (25-OH-D₃) separately has been shown to improve Ca and P retention, which through various molecular mechanisms, thereby increase pork tenderness. However, there is very little research investigating the combination of phytase and 25-OH-D₃ on pork quality. Therefore, the objective of this study was to examine the effect of supplementing both phytase and 25-OH-D₃ in low P finisher diets on pig performance, nutrient and mineral digestibility, bone mineralisation and pork quality. A total of 120 pigs were selected for a 2 × 2 factorial design. The pigs (60 male and 60 female) were blocked according to body weight (BW) and sex and allocated to the one of four dietary treatments: low P (4.81 g/kg) diet (basal) (T1); low P diet + phytase (T2); low P diet + 25-OH-D₃ (T3) and low P diet + phytase + 25-OH-D₃ (T4). Average daily feed intake (ADFI) was measured with single space computerized feeders, which allowed individual ad libitum feeding and daily recording of dietary intake. At the end of the 55-day feeding period (108.4 ± 8.73 kg), the pigs were slaughtered. A blood sample was taken and back-fat thickness and lean meat content were measured.

Pigs supplemented with phytase had a lower ADFI and lower feed conversion ratio (FCR) compared to pigs offered the non-phytase diets. Phytase supplemented diets produced a higher coefficient of apparent total tract digestibility (CATTD) of ash, phosphorous (P) and calcium (Ca) compared with the non-phytase supplemented diets. There was no interaction between phytase x 25-OH-D₃ on bone parameters, but there was a significant interaction between phytase and 25-OH-D₃ on cook loss. Pigs offered 25-OH-D₃ had increased cook loss over the basal diet; however, there was no effect on cook loss when phytase and 25-OH-D₃ were offered in combination compared to the phytase only diet.

In conclusion, there was no benefit to offering a combination of phytase and 25-OH-D₃ on pig performance, bone parameters or pork quality.

Duffy, S. K., Kelly, A. K., Rajauria, G., Clarke, L. C., Gath, V., Monahan, F. J., O'Doherty, J. V. (2018). The effect of 25-hydroxyvitamin D3 and phytase inclusion on pig performance, bone parameters and pork quality in finisher pigs. Journal of Animal Physiology and Animal Nutrition, 102(5), 1296-1305. https://doi.org/10.1111/jpn.12939