Growth and Mineral Absorption by Striped Bass Morone saxatilis Fed a Plant Feedstuff Based Diet Supplemented with Phytase

Abstract

Two experiments were conducted to determine the effects of phytase on growth, apparent phosphorus (P), calcium (Ca), iron (Fe), zinc (Zn), magnesium (Mg), and copper (Cu) absorption, and apparent protein digestibility by striped bass Morone saxatills fed a high phytate diet. In experiment one, four diets with graded levels of phytase supplementation, 0, 500, 1,000, and 2,000 phytase units/kg of diet (PUkg), and a diet supplemented with inorganic P (positive control, total P, 0.73%; phytin P, 0.35%) were assigned to duplicate tanks, and were fed to fingerling striped bass for 16 wk. A digestibility trial was conducted at weeks 16-18, using 0.5% Cr20J as an indigestible marker in the diets. Phytase was sprayed post-extrusion on the basal diet (P-total, 0.58%; P-phytin, 0.35%). Experiment two consisted of a 2-wk digestibility trial with three treatments: 0 (basal; total P, 0.73%; phytin P, 0.34%), 1,000, and 2,000 PUkg, assigned to four, three and three replicate tanks respectively. Each tank contained an average of 20 striped bass (mean weight: 400 9). The diet used was similar to the basal in experiment one, which was modified to have low essential trace mineral concentrations, in order to increase the sensitivity of the assay. In experiment one, significant improvements (P 5 0.05) in growth, feed conversion ratios, and vertebral and scale ash concentrations of fish at the end of the experiment were achieved with either added inorganic P or increasing phytase supplementations. Results from both digestibility trials indicated that P absorption was improved with the addition of at least 500 PUkg. Absorptions of Ca and Fe were significantly increased (P 5 0.05) and Zn absorption marginally improved (P 5 0.06) when at least 2,000 PUkg was supplemented to the diet. Protein digestibility, Mg and Cu absorption were not significantly different in any treatment. Whole carcass P retention was significantly improved with the addition of 1,OOO PUkg, and 2,000 PUkg, when compared to fish fed the basal diet, 500 PUkg and positive control treatments. Results from these experiments indicate that phytase supplementation of at least 1,OOO PUkg is adequate to maintain growth rate and health comparable to an inorganic P supplemented diet. In addition, bioavailability and utilization of P is increased with increasing phytase supplementation. Diet supplementation of 2,000 PUkg increased Ca, Fe, and Zn digestibility by striped bass fed a high phytate diet.Feed costs in aquaculture operations account for approximately 50% of total operational costs (Ratafia 1994). It is, there-fore, critical that future research on fish feed for cultured species will find ways to reduce these costs and enable increased nutrient utilization of the diets. Currently most practical fish feeds for carnivorous fish,

FLUCTUATION OF POST-PRANDIAL PLASMA MINERAL LEVEL OF JUVENILE JAPANESE FLOUNDER, Paralichthys olivaceus FED DIETARY PHOSPHORUS AND PHYTASE SUPPLEMENTATION

“…Similar finding was reported on Atlantic salmon that increasing of IP6 inclusion resulted in a progressive decrease of digestibility of Mg and Zn (Denstadli et al, 2006). In contrast, Papatryphon et al (1999) found that Ca was more associated with the phytate complex than other minerals in striped bass.…”

Effect of Phytase on Growth and Phosphorus Utilization in Japanese Flounder (Paralichthys olivaceus)

“…The advantageous effects of phytase in SBM-containing diets were confirmed in this feeding experiment with improved growth performance, feed conversion, feed efficiency, P and protein digestibility and mineral utilization by Japanese flounder. It has been reported that dietary phytase improved growth and overall performance while reducing P excretion in rainbow trout, Oncorhynchus mykiss (Rodehutscord andPfeiffer 1995, Sugiura et al 2001), carp, Cyprinus carpio (Schafer et al 1995) and striped bass, Morone saxatilis (Papatryphon et al 1999). This study demonstrated that the addition of 150 FTU or more in SBMcontaining diets improved the FCR of Japanese flounder compared to a…”

“…The results of the present study indicate that phytase in the diets improved P and protein retention. It is also reported that improved P retention was found with phytase (2000 FTU/kg diet) supplemented in soybean meal and canola meal diets in striped bass (Papatryphon 1999) and in Atlantic salmon (Sajjadi et al 2004). In our study, phytase enhanced protein retention, suggesting that phytase reduces formation of phytate-protein complexes in the gut and causes an improvement in utilization.…”

“…For proximate analysis and determination of whole-body P concentrations, fish were pooled and homogenized in a mincing machine. The phosphorus retention in flounder after 8 weeks of feeding was calculated as described previously (Papatryphon et al 1999). The proximate analyses were determined according to the AOAC method (AOAC 1995).…”

Effect of Beta-propeller Phytase from Pichia pastoris on Energy Partition in Juvenile Litopenaeus vannamei Fed a Plant Protein-Based Diet

“…However, plant protein sources have limitations related to decreased feed intake due to lack of appetability for shrimp, and by the presence of phytate, an antinutritional factor (AF), which limits bioavailability of phosphorus and other minerals (Lee and Meyers, 1996;Mendoza, Aguilera, & Montemayor, 2000). Phytateor inositol hexaphosphate (myo-inositol-1,2,3,4,5,6-hexaphosphate) is classified as a poly-anionic molecule that may chelate strongly with cations such as Ca ++, Mg ++ , Zn ++ , Cu ++ , Fe +++ , and K + , forming insoluble salts (Kumar, Sinha Makkar, Boech, & Becker, 2011) and reducing absorption of these minerals (Papatryphon, Howell, & Soares, 1999). P excretion is another consequence of the low digestibility of plant ingredients high in phytate and other AF for aquatic organisms.…”