Effects of wheat proteins on growth performance
Because of its high digestibility and its absence of anti-nutritional factors, replacement of a large proportion of FM with VWG results in similar growth performance and fish composition whatever the species are. The apparent CP digestibility of VWG is high, between
Advanced Feature Extrusion
sulphur amino acids and leucine. They contain rather low levels of lysine, tryptophan, and arginine meaning that they should be complemented with these amino acids when used at high level in formulae. Several experiments showed WP can successfully replace a large part of FM when diets are supplemented with free lysine in salmonids (Davies et al., 1997). WPs contain a relatively high concentration of sulphur-containing amino acids, due to the numerous di-sulphur bonds (1.8 percent CP of methionine and 2.6 percent CP of cysteine), whereas PP sources are generally low in sulphur-containing amino acids. For instance, soybean meal and soy protein concentrate respectively contain 1.4 and 1.3 g/100 g CP of methionine and 1.3 and 1.4 g/100 g CP of cysteine. Furthermore, WPs are high in leucine, with about 7.9 g/100 g CP. Leucine is considered as the main amino acid triggering muscle protein synthesis and inhibiting proteolysis in mammals (Li et al., 2009) and probably in fish. Indeed, in different species, amino acids regulate the TOR signalling pathway (Seilliez et al., 2008). Furthermore, supplementing media containing 0.6 mM leucine with an additional 2.5 mM leucine reduced rates of protein degradation in rainbow trout primary myocytes by 8 percent (Cleveland, 2010). WPs are also rich in glutamine: from 35 to 40 percent CP. Glutamine is a major substrate for all rapidly proliferating cells and plays an important role in maintaining intestinal trophicity (VerlhacTrichet, 2010). In addition, glutamine is one of the most important energy substrates of enterocytes. Free glutamine significantly increases enterocyte and microvilli length in catfish gut (Pohlenz et al., 2012), hybrid striped bass (Cheng et al., 2012), and juvenile hybrid sturgeon (Zhu et al., 2011). Glutamine also constitutes a major substrate for immune cells, thus modulating immune response (Verlhac-Trichet, 2010; Zhu et al., 2011; Cheng et al., 2012). Moreover, glutamine plays a role in eliminating free radicals as it acts as a precursor for glutathione synthesis (Wu, 1998). Such effects are reported for juvenile hybrid sturgeon (Zhu et al., 2011) and hybrid striped bass (Cheng et al., 2012). Glutamine has proven to stimulate muscle synthesis in terrestrial vertebrates but such results are not available for fish. However, dietary glutamine supplementation increases growth performance in juvenile hybrid sturgeon (Qiyou et al., 2011) and in hybrid striped bass (Cheng et al., 2012).
30.38  BIN Inlet
Engineered Pre-Kill Zones
Optimize Petfood Safety Food safety is rapidly changing the way the world looks at pet foods. Extru-Tech recently introduced “Advanced Features” to their line of Extruders that provide: 1.93 
• Best in class design reduces horizontal surfaces and increases sanitation18.00 access under, on and  1.00 around NPT the unit • Incorporates Advanced Venting Technology (AVT) for suppression of steam and renegade product mist 03
• Becomes the first line of defense in control/ elimination of potentially dangerous pathogens. 80
MAXUM SIZE 10
• Completed an industry-first scientific validation study proving the kill/lethality step of the ExtruTech extrusion system design 52.19  • All of these advanced features and validation in 102.13  one extrusion system 111.12 
195.72  With increased focus on food safety, Extru-Tech’s Advanced Feature Extrusion puts you well ahead of previous and current industry standards.
Contact a system specialist today at 785-284-2153 or visit us online at www.extru-techinc.com.
Figure 1: Nitrogen apparent digestibility of a fish-meal based diet where fish meal is replaced from 0 to 75% by hydrolysed wheat gluten (HWG), on a Crude Protein basis. Nitrogen apparent digestibility curvilinearly increases with increasing HWG in diet.
ET-261A.indd 1AQUAFEED | 15 March-April 2015 | INTERNATIONAL
P.O. Box 8 100 Airport Road Sabetha, KS 66534, USA Phone: 785-284-2153 Fax: 785-284-3143 firstname.lastname@example.org www.extru-techinc.com
2/12/15 4:52 PM
The March - April 2015 edition of International Aquafeed magazine