Influence of Phytase Supplementation at Increasing Doses from 0 to 1500 FTU/kg on Growth Performance, Nutrient Digestibility, and Bone Status in Grower–Finisher Pigs Fed Phosphorus-Deficient Diets

Abstract

The objective of the current study is to assess the effects of the inclusion of 6-n phytase to a phosphorous-deficient diet on the growth performance (feed intake, average daily gain, and feed conversion ratio), apparent digestibility of calcium and phosphorus, and bone characteristics of grower–finisher pigs. The experimental diets included a phosphorus-deficient diet containing 0 (negative control), 250, 500, 1000, or 1500 FTU/kg of 6-phytase, and a diet formulated to meet the phosphorus nutrient requirements of pigs (positive control). Pigs were fed the experimental diets from the time they were ~35 kg body weight until they reached slaughter weight of ~110 kg. Bone status of the metacarpal (ash, mineral content) and femur (mineralization, geometry, and mechanical strength) bones were assessed. There was no effect of dietary treatment on feed intake. Feed conversion ratio was improved following inclusion of phytase at a dose of 500 FTU/kg or higher. Phytase inclusion at a dose of 1000 FTU/kg increased the average daily weight gain of grower–finisher pigs. Phytase inclusion at a dose of 500 FTU/kg was sufficient to increase metacarpal phosphorus content. Femur mid-diaphysis ash percentage was significantly increased even after the inclusion of the lowest dose of phytase. Analysis of structural parameters of femur mechanical strength (Young’s modulus, yield stress, yield strain, ultimate stress, ultimate strain) showed that the inclusion of a phytase dose of 500 FTU/kg in growing/finishing diets was sufficient to significantly improve bone status of grower–finisher pigs at slaughter.

A New Biosynthetic 6-Phytase Added at 500 Phytase Unit/kg Diet Improves Growth Performance, Bone Mineralization, and Nutrient Digestibility and Retention in Weaned Piglets and Growing–Finishing Pigs

“…This could be an indicator that reducing digestible P and Ca similarly by 0.14, 0.11, and 0.10% points, respectively, in phases 1, 2, and 3 relative to the FEDNA [ 14 ] recommended level in growing–finishing pigs was sufficient to induce negative effects not only on growth performance but also on bone mineralization. In agreement with the data generated with other exogenous phytases [ 42 , 43 ], phytase supplementation at 500 FTU/kg diet in P- and Ca-deficient diets improved the ash, P, and Ca contents in the metacarpal bones of growing pigs. The levels of the metacarpal bones’ dry weight, ash, P, and Ca contents in animals fed with the phytase-supplemented diets became equivalent to those fed with the PC-nutrient adequate diets.…”

Phytase Supplementation of Growing-Finishing Pig Diets with Extruded Soya Seeds and Rapeseed Meal Improves Bone Mineralization and Carcass and Meat Quality

“…Wiśniewska et al [ 11 ] and Wu et al [ 28 ] found a positive correlation between percentage improvements in feed efficiency in response to phytase and dietary phytate content, including for diets based on legume seeds, SBM, or RSM [ 29 , 30 ]. Grela et al [ 31 ] observed that a dietary phytase treatment at doses of 500–1000 FTU per kg significantly influenced daily gains and the FCR, but the FI was not affected. Other studies showed that phytase enhanced the utilization of some nutrients, but it was not always connected with increased performance [ 29 , 32 ].…”

“…This ability increases with the dose of the enzyme, as reported by other authors [ 10 , 34 ]. Grela et al [ 31 ] found that the administration of 500 FTU of phytase/kg of diet increased bone strength. Kasprowicz-Potocka et al [ 7 ] found that the phytase additive improved the availability of P and Ca in pigs’ diet by 14.34% and 4.08%, respectively.…”

Markers of bone turnover and biomechanical properties of the third metacarpal bone of growing pigs subjected to the different dietary phosphorus and calcium content

“…According to nutritional recommendation (NRC, 2012) the ratio of total calcium to digestible phosphorus for growing pigs should amount to 2.1. When they are unbalanced, insoluble and indigestible calcium-phosphorus complexes can form in the intestines (Masuyama et al, 2003, Selle et al, 2009 influencing body mineral balance, achievement of peak bone mass (Heaney et al, 2000), bone mineral density (Sørensen et al, b, 2019Grela et al, 2020), metabolites of bone turnover (Liesegang et al, 2002;Drews et al, 2016;Sørensen et al, 2018 b;Gerlinger et al, 2019), and consequently bone material properties and strength (Huttunen et al, 2007;Grela et al, 2020).…”

“…However, some authors (Rieger, 2021) indicate that dietary phosphorus has greater, than calcium, impact on bone morphology and mechanic properties. The availability of phosphorus from plant feeds can be increased by the addition of microbial phytase to the animals' diet, which also has a positive effect on the physicochemical status of bones (Grela et al, 2020).…”