Effects of phytase pretreatment of soybean meal and phytase-sprayed in diets on growth, apparent digestibility coefficient and nutrient excretion of rainbow trout (Oncorhynchus mykiss Walbaum)

Abstract

Rainbow trout were fed a diet containing phytase-sprayed and phytasepretreated soybean meal with different phytase levels. The single factor random block design was used to analyze the effects on rainbow trout of dietary phytase supplementation on growth performance, nutritional ingredient digestibility and nutrient excretion. After 90 days, the results showed that feed conversion ratio (FCR) and protein efficiency ratio (PER) were significantly improved and specific growth rate (SGR) was not affected by spraying phytase, but SGR, FCR and PER were not significantly improved by phytase pretreatment. A digestibility trial conducted after the feeding trial showed that apparent digestibility coefficient (ADC) of diet protein and minerals was increased with phytase supplementation. However, there was a negative effect of phytase on the ADC of lipid. The excretion experiment showed that the supplementation of phytase resulted in decreased nutrient excretion in feces, but lipid excretion was slightly increased with phytase supplementation. In addition, the results of P excretion and ADC of P analyzed by t-test showed that phytase pre-treatment method should be a more rational method than the spraying method. The results of SGR, ADC of P and P excretion analyzed by quadratic regression indicated that 2,000-3,000 U/kg levels by the spraying method could be a rational range of phytase supplementation, and about 1,000 U/kg should be an optimal level by the pretreatment method. Thus, use of phytase in rainbow trout feeds can have economic and environmental benefits.

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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).…”

“…Soybean storages most of its P as phytic acid (myo-inositol 1,2,3,5,6-hexakis dihydrogen phosphate), an organic compound that once in the digestive tract, usually forms complexes phytate-protein or phytate-mineral-protein (Cheryan, 1980) or binds to trypsin (Singh and Krikorian, 1982) that reduces the digestibility (Gatlin et al, 2007) and P is usually excreted in the urine and/or feces (Coloso et al, 2003), which is a major concern of aquaculture operations, as it can cause eutrophication of water bodies surrounding the farms (Bureau and Cho, 1999). Phytase is a phosphohydrolase enzyme that catalyses the sequential release of inorganic orthophosphate from the phytic acid (Jorquera et al, 2008) and has been suggested as supplement in diets with soybean meal (Wang et al, 2009) to improve P retention and thus, decreased its excretion. After the feeding trials and with the addition of phyatse to diets with soybean meal, as expected, the P excretion was lower than the commercial diet.…”

“…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.…”

Use of phytase at graded levels for improving nutrient digestibility, growth and hematology of Catla catla fingerlings fed Moringa oleifera seed meal (MOSM) based diet

“…However, decreased EE digestibility was found in O. mykiss fed phytase supplemented soybean meal based diet. The probable reason for this reduction in fat digestibility might be that the phytase supplementation inhibited lipase activity which led to decreased lipase hydrolysis efficiency for lipids, resulting in reduced lipid digestibility (Wang et al, 2009). …”

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

“…Several β-propeller phytases, one from B. subtilis (Guerrero-Olazarán, Rodríguez-Blanco, Carreon-Treviño, Gallegos-López, Viader-Salvadó, 2010), and others designed by a structure-guided consensus approach, have been produced by the methylotrophic yeast P. pastoris (Viader-Salvadó, Gallegos-López, Carreón-Treviño, Castillo-Galván, Rojo-Domínguez, & Guerrero-Olazarán, 2010). Therefore, during the last two decades, optimizing plant-based diets using phytase as a feed additive has been a way to reduce phytates' antinutritional effect (Fox, Lawrence, Saccardi, Davis, Ricque-Marie, Cruz-Suarez, & Samocha 2006;Lei et al, 2007;Lim & Lee, 2009), thereby improving the absorption and retention of minerals and amino acids (Rebollar and Mateos, 1999;Gómez-Villalva, 2005), and enhancing the activity of proteolytic enzymes, survival rate, and weight gain (Ricque-Marie, Cruz-Suarez, Zavala-Chavez, Nieto-Lopez, Guajardo, Tapia-Salazar, McCallum, & Newkirk, 2004;Cao, Ye, Wang, & Guo, 2010;Wang, Yang, Han, Dong, Yang, & Zou, 2009;Gamboa, Aguilera, Gaxiola, Cuzon, Guerrero, & López, 2011). The digestive tract of shrimp has a pH range of 6-8, hence FTEII is a good alternative for either pretreatment with fresh water added to meals or direct inclusion in shrimp feed.…”