Comparative efficacy of monocalcium phosphate and WINDMill® Aquaphos on the growth performance, phosphorus retention and digestibility in Nile tilapia Oreochromis niloticus

A study was undertaken to evaluate the effect of two supplemental phosphate sources, Windmill® Aquaphos (MAP) and monocalcium phosphate (MCP, Aliphos® Monocal) on the growth performance, whole-body phosphorus (P) and calcium (Ca) retention, P and Ca digestibility and bone mineral composition of Nile tilapia.

The trial comprised three dietary treatments: a negative control diet (NC) without inorganic P supplementation; two other diets based on the NC formulation were supplemented with either MCP at 1.22% or Windmill® Aquaphos at 1.07%. Dietary total P levels were 0.60, 0.86 and 0.88 %DM for the NC, MCP and MAP diets, respectively. Diets were isonitrogenous (crude protein, 35% DM), isolipidic (9% DM) and isoenergetic (gross energy, 19.5 MJ/kg DM). Quadruplicate groups of 40 tilapias, with a mean initial body weight of 19.0 ± 1.2 g were fed one of the three experimental diets during 61 days.

In this trial, fish fed the MAP diet showed a significantly higher FBW than those fed the MCP and control diet (P<0.05). Fish fed the MCP and MAP diets showed a significantly lower FCR than those fed the NC (P<0.05).

In comparison to the NC, both MCP and MAP diets resulted in significantly higher ash, phosphorus and calcium content in vertebral bone (P<0.05). In comparison to the NC, both MCP and MAP diets resulted in a significantly higher retention of protein, phosphorus and calcium at the whole-body level (P<0.05). Phosphorus digestibility of the MAP diet was significantly higher than that of the MCP and NC diet (P<0.05). Daily P gain with the MAP diet was significantly higher than that achieved with the MCP and NC (P<0.05) diets. Fish fed the MAP diet showed also significantly lower daily fecal P losses than fish fed the MCP and NC diets (P<0.05).

Overall data confirms that both supplemental phosphate sources (MCP and MAP) are an effective strategy to enhance growth performance and P utilization in Nile tilapia. On a comparative basis against MCP, the MAP product (Windmill® Aquaphos) resulted on further gains in terms of FBW, P digestibility, body P gain and lower fecal P losses, making it a valuable nutritional tool to minimize the environmental impact of tilapia farming.