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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

15.00 [381]

Ă12.00 [305]

36.91 [937]


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).

67.28 [1709]

101.44 [2577]

30.38 [772] BIN Inlet

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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

2/12/15 4:52 PM

Mar | Apr 2015 - International Aquafeed magazine  

The March - April 2015 edition of International Aquafeed magazine

Mar | Apr 2015 - International Aquafeed magazine  

The March - April 2015 edition of International Aquafeed magazine