Effect of protease and phytase supplementation on growth performance and nutrient digestibility of rainbow trout (Oncorhynchus mykiss, Walbaum) fed soybean meal-based diets

Abstract

An experiment was conducted to evaluate effects on growth, body composition and nutrient digestibility of addition protease and phytase to soybean meal-based diet in rainbow trout. Seven soybean meal-based diets were prepared by adding protease, phytase and mixture of both enzymes at two different levels (1 and 2 g kg −1 ) to a base diet without enzymes. Mixed enzymes (1, 2 g kg −1 ) were prepared by adding protease and phytase at the same doses (0.5 + 0.5 and 1 + 1 g kg −1 ). Diets consisted of 31% fish meal and 44% dehulled hexane extracted soybean meal. At the start of the experiment, 45 rainbow trout (initial mean body weight 88 g) were stocked into each of 21 fibre tanks. After 90 days, there were no significant differences on the growth, feed conversion ratio, digestibility of protein and lipid among the groups. Results of this study showed that the addition of protease or phytase as mix to soybean mealbased diet could not increase growth and nutrient digestibility in trout.ARTICLE HISTORY

Growth response of African catfish, Clarias gariepinus (B.), larvae and fingerlings fed protease‐incorporated diets

“…On the other hand, Dalsgaard et al (2012) found no significant differences in growth parameters and FCR of rainbow trout, Oncorhynchus mykiss, while ADC of protein moderately improved due to the addition of protease to soybean meal diet. Yigit et al (2018) found that protease supplementation to rainbow trout had no significant effect on growth, FCR, and protein and dry matter digestibility. Yigit et al (2018) found that protease supplementation to rainbow trout had no significant effect on growth, FCR, and protein and dry matter digestibility.…”

“…Ayhan et al (2008) also reported that the addition of protease to soybean meal diets for gilthead seabream (Sparus aurata) larvae had no effect on growth and protein digestibility. Yigit et al (2018) found that protease supplementation to rainbow trout had no significant effect on growth, FCR, and protein and dry matter digestibility.…”

“…In recent years, functional diets have become a topic of interest for improving the performance and the health status of the farmed fish (Abdel-Tawwab, 2016;Ayhan, Diler, Arabaci, & Sevgili, 2008;Dalsgaard et al, 2012;Yigit, Bahadir Koca, Didinen, & Diler, 2018). One of those feed supplements is a dietary protease, which was incorporated to fish diets to improve protein digestion and utilization, which in turn have beneficial effects on fish growth (Drew, Racz, Gauthier, & Thiessen, 2005;Li, Chai, Liu, Chowdhury, & Leng, 2016;Liu, Wu, Li, Duan, & Wen, 2018;Oxenboll, Pontoppidan, & Fru-Nji, 2011).…”

Exogenous enzymes as functional additives in finfish aquaculture

“…However, in some fish, dietary phytase may exhibit insignificantly or none effect on the growth performance and feed efficiency. For instance, the supplementation of phytase did not significantly enhance the growth response of Japanese sea bass, which was consistent with the results that the addition of phytase to diets including soybean meal does not affect growth and FCR in rainbow trout (Yigit et al, ), and the addition of phytase to diet containing soybean meal in seabream had no effect on the growth performance (Ayhan et al, ). Sajjadi & Carter () also stated that no effect on growth and feed efficiency was observed after phytase supplemented to diet (canola meal) of Atlantic salmon.…”

“…In spite of this, this speculation was not absolutely correct. In some cases, the addition of protease and phytase to the basic diet had no significant effect on the growth parameters, FCR and nutrient digestibility of rainbow trout (Yigit et al, ). A multienzyme (Superzyme CS: xylanase, amylase, cellulase, protease and β‐glucanase) introduced into diet of rainbow trout showed no significant effect on the growth performance (Ogunkoya et al, ).…”