From an economic and environmental perspective, P constitutes a significant proportion of the expenditure associated with mineral supplementation in diet formulations. The identification of P sources and their bioavailability in Litopenaeus vannamei diets assumes critical importance due to consequences of excessive phosphorus loads. The fishmeal replacement by alternative sources in shrimp diets has led to heightened interest in supplementing diets with inorganic phosphates, particularly in cases where high levels of vegetable meal are incorporated at elevated dietary levels. Thus, recent studies have assessed the availability of various inorganic P sources in shrimp feeds , investigating digestibility and growth performance with dicalcium (DCP), monocalcium (MCP), monoammonium (MAP), and monopotassium phosphates (MKP). Nevertheless, these studies predominantly utilized semi-purified diets (Milián-Sorribes et al., 2021 ) or suboptimal P levels in the feed (Lemos et al., 2021). Consequently, the objective of the current experiment was to assess to evaluate these aspects with standard diet formulations, considering both nutritional and environmental perspectives.
With this aim four trials were carried out: First and second trials were developed to establish the best inert marker (IM) for digestibility evaluation using four inert markers in a standard diet (Cr, Y, La and Ce) analyzing the diet digestibility and the inert marker retention in whole body, cephalothorax, and muscles (with and without intestine). The third and fourth trial were carried out to assess the P use of three P sources: monoammonium phosphate (MAP, NH4H2PO4), monosodium/monocalcium phosphate (SCP-2%, NaH2PO4/Ca(H2PO4)2·H2O in proportion 12/88) and monosodium phosphate (MSP, NaH2PO4) usi ng a Control diet without P supplement.
Regarding the IM results, Y resulted the best option to establish the digestibility due to the high solubility after acid digestion and the lowest Y retention in the shrimp whole body when was compared with the other markers.
In the digestibility trial (Table 1 ) Control diet obtained the lowest P digestibility, because raw materials had lower P digestibility than the P from inorganic phosphates. Likewise, diet SCP- 2% presented the best Ca digestibility values. The excretion of N or P did not present significant relevant differences, but when P and N excretion and retention was evaluated jointly with P and N digestibility (Fig. 1) the SCP-2% diet generated the lowest N waste in relation to the N intake . The MAP diet presented the highest amount of N residues due to N excretion , that was greater than in the rest of the diets, followed by the control diet.
Lemos et al. https://doi.org/10.1007/s10499-021-00651-3
Milián-Sorribes et al.10.3390/ani11061700.