Effects of Microbial Phytase Supplementation and Dosage on Apparent Digestibility Coefficients of Nutrients and Dry Matter in Soybean Product‐Based Diets for Rainbow Trout Oncorhynchus mykiss

Abstract

Three experiments were conducted to evaluate the effects of microbial phytase (Ronozyme P(L) and dosage on apparent digestibility coefficients of dry matter, crude protein, amino acids, and minerals in soybean product‐based diets for rainbow trout Oncorhynchus mykiss. In experiments 1 and 2, fish were fed soy protein concentrate and soybean meal‐based semi‐purified diets, respectively. In experiment 3, fish were fed soybean meal‐based practical diets. A total of 900 fish (average body weight 100.1 ± 7.4 g) were stocked into 30 150‐L fiberglass tanks with 30 fish per tank and two tanks per diet. Phytase was supplemented into soybean product‐based diets at 0, 500, 1,000, 2,000, and 4,000 FTU/kg diet. Yttrium oxide (0.01%) was used as inert marker. Feces were collected by hand stripping three times at 3‐d intervals. Results of experiments 1 and 2 showed that phytase supplementation significantly increased apparent digestibility coefficients of minerals (except copper and iron), but not dry matter. Experiment 3 showed that phytase supplementation significantly increased apparent digestibility coefficients of dry matter, crude protein, amino acids (except tryptophan and tyrosine), and minerals (except copper and iron). The optimum level of phytase supplementation in rainbow trout diets was approximately 500 FTU/kg diet.

Dietary supplementation of exogenous carbohydrase enzymes in fish nutrition: A review

“…In aquaculture, the use of phytase to improve phosphorus utilization from plant feedstuffs has emerged quite rapidly (Cao et al, 2007;Cheng et al, 2004;Dalsgaard et al, 2009;Kumar et al, 2012). However, in the case of carbohydrase enzymes, their use in aquaculture feeds has not been as nearly as widespread, regardless of their positive effects on nutrient digestibility (Adeola and Cowieson, 2011).…”

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“…The same was found when SGR was compared with those obtained by Gomes et al (1995) and Wang et al (2009) when fed rainbow trout juveniles with soybean meal and the inclusion of phytase. The addition of phytase has been related to an improvement of growth in salmonids, mainly because phytic acid is hydrolysed and allows a better digestion process (Cheng et al, 2004). Phytase was added to the experimental diets at a level of 0.4 g/kg, about 2,000 FYT/kg, and it seems to be an adequate level to be included when 400 g/kg of soybean is used.…”

“…Three experimental diets were prepared by adding the Baker's yeast (Diet Y, 15 g/kg diet), phytase (Diet Ph, 0.4 g/kg diet) or a combination of both (Diet Y+Ph,15 and 0.4 g,respectively). Phytase was added according to Cheng et al (2004) and obtained from DSM Nutritonal Products of Mexico (Ronozyme P5000, 5,000 FYT/g). In the other hand, the yeast (Saccharomyces sp., approximately 8.5 x 10 9 cells/g) was added according with Lara-Flores et al (2003) and obtained from a local baker shop.…”

“…A way to reduce the effect of this compound is by using phytase, a phosphohydrolase enzyme that catalyse the release of P from the phytic acid (Jorquera et al, 2008). Several authors (Cheng and Hardy, 2003;Cheng et al, 2004;Wang et al, 2009) found that the apparent digestibility of protein from soybean meal was improved with the inclusion of phytase. Recently (Cruz et al, 2011) it was report that juveniles of rainbow trout fed a diet with soybean meal (400 g/kg diet) as main source of protein and phytase (0.8 g/kg diet) had a similar growth performance and showed a reduction in P and N excretion, compared to those fed a commercial diet and one with fishmeal as sole protein source.…”

Optimum Dietary Ca/P Ratio and Phytase for Growth and Bone Mineralization in Juvenile Clarias gariepinus Fed Soya Bean-Based Diet

“…The optimum dose changes along with many factors such as fish species, different phytase sources, diet formulation (amount of substrate for phytase) and selected response parameters [7]. Optimum phytase has been determined for Channel catfish [13,14], Nile tilapia [15], Korean rockfish [16], Pangasius pangasius [17], and Rainbow trout [18]. Van weerd et al [19] and Nwanna et al [20] reported 750 FTU/g (Natuphos 5000) and 8000 FTU/g (Ronozyme 5000) phytase, respectively, as optimum for growth of Clarias gariepinus, but did not consider consistently increasing levels of soya bean used in their studies.…”