Coronavirus may lead to replacing phosphorus in broiler diets with higher doses of phytase

Dr Jae Cheol Kim speaking at the 2019 Pig Feed Quality Conference in Bangkok.

The global price of inorganic phosphorus has increased significantly due to regional and international supply chain disruptions as a result of the Covid-19 epidemic. Dr Jae Cheol Kim of AB Vista reports an unpublished feeding trial conducted by a broiler integrator in Southeast Asia. It shows super-dosing with an enhanced E.coli phytase in normal or low phosphorous or low calcium corn-soy diets can significantly reduce or even completely replace inorganic phosphorous with no loss of performance.

Trial design

The study used 2400 newly hatched commercial straight-run broiler chicks (Lohman Indian 85 River) randomly allocated into 5 dietary treatments with 16 replicate pens per treatment and 30 chicks per floor pen.

The positive control diets were corn-soybean meal-based diets containing 0.40/0.80%, 0.35/0.70%, and 0.30/0.60% available phosphorus (avP) and total calcium (Ca), respectively from 0-10, 10-25, and 26-42 days post-hatch (PC). An additional PC diet (PC++) containing extra avP and Ca (+0.05% avP/+0.1% Ca) to that of PC was included to test if avP and Ca in the PC diet were limiting.

Three test diets were formulated with 500, 1000, and 1500 FTU/kg of phytase assigned respectively an avP matrix of 0.15, 0.19, and 0.23% and a fixed Ca matrix of 0.15%. Analysed phytate phosphorus contents of the experimental diets were 0.25-0.26%. Based on the formulation, inclusion of monocalcium phosphate (MCP) in each phase diet and total use of MCP in each treatment are presented in Figure 1.

As it can be seen MCP inclusions in all diets were significantly reduced, and MCP was completely excluded in the grower and finisher diets with 1500 FTU and the finisher diets with 1000 FTU enhanced E. coli phytase (Quantum Blue, AB Vista). More importantly, the total amount of MCP used during the 42-day production cycle was reduced from 34.3 kg to 13.0, 6.9 and 2.6 kg per MT of feed in 500, 1000, and 1500 FTU phytase treatments with full avP matrix application (Figure 1).

These savings are equivalent to 62%, 80%, and 92% reduction in MCP inclusion with dose of 500, 1000, and 1500 FTU phytase, respectively. With the current global market price of inorganic phosphorus, such a significant reduction will certainly translate to significant savings in diet cost.

Performance results

Bodyweight and FCR results are presented in Figure 2. Supplementing an extra 0.05% avP and 0.1% total Ca (PC++) did not improve performance at any stage of growth and even significantly reduced body weight in the first 10 days (p<0.05), indicating that the avP and Ca in the control diet (PC) was not limiting P and Ca for optimum growth.

Then gradual reduction of MCP inclusion with increasing supplementation of phytase and avP matrix had no impact on overall 42-day body weight and FCR, although >1000 FTU phytase with avP matrix application significantly increased body weight in the starter and grower phase.

Conclusion

The results provide an answer for the question whether inorganic phosphorus supplementation can completely be excluded with super-dosing of an efficient phytase. It is demonstrated that significant reduction or even complete exclusion of inorganic phosphorus in the diets for broilers with supplementation of 1000 – 1500 FTU Quantum Blue with full avP matrix application supported optimal growth performance of broilers.

Considering increasing market price of inorganic phosphorus, a significant opportunity exists for feedmillers and integrators to reduce diet cost and also to reduce phosphorus pollution from animal production by adapting super-dosing of an efficient phytase as a dietary strategy.


*Dr Jae Cheol Kim (jae.kim@abvista.com) is Technical Manager ASPAC with AB Vista, Singapore. References are available on request to the author. The complete technical article ‘Can we completely exclude inorganic phosphorus in broiler diets with higher doses of phytase?’ will be published in Asian Poultry Magazine.

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