Evaluation of an in vitro digestibility technique for the prediction of protein digestibility in the South African abalone, Haliotis midae L.

Abstract

A pH‐stat multienzyme in vitro digestibility assay was investigated for its efficacy in predicting apparent protein digestibility coefficients in abalone diets. Linear regression analysis between in vitro digestibility estimates and in vivo digestibility coefficients obtained from abalone, revealed that the technique could be used to reliably predict apparent protein digestibility. Maximal predictability of the system was obtained when protein sources were analysed according to origin – animal or plant. The technique was used to assess the apparent protein digestibility of 34 potential protein sources for use in formulated feeds for Haliotis midae.

Species specific in vitro protein digestion (pH-stat) for fish: method development and application for juvenile rainbow trout (Oncorhynchus mykiss), cobia (Rachycentron canadum), and Nile tilapia (Oreochromis niloticus)

“…Apart from correlation and method validation, the pH-stat in vitro DH technique may be important to qualify or distinguish raw materials, indicating how much it could be potentially hydrolyzed in the fish digestive tract and, to a certain extent, the availability for absorption. The complex nature of food digestion in the live fish may not be easily replicated and it may also not be strictly required for consistent screening of feed protein quality, as demonstrated for farmed land and aquatic species (Boisen and Eggum, 1991;Boisen and Fernández, 1995;Pedersen and Eggum, 1983;Shipton and Britz, 2002;Tibbetts et al, 2011b). The DH has emerged with potential as an accessory method in quality control of raw materials in the aqua feed manufacturing industry (De Muylder et al, 2008;Lemos and Tacon, 2011).…”

“…This motivated the development of in vitro methods based on the digestion of small amounts of feedstuff samples. Reported in vitro protein digestion methods include the use of digestive enzymes that may be available from commercial sources (Lazo et al, 1998;Shipton and Britz, 2002;Tonheim et al, 2007) or recovered from the target species Ezquerra et al, 1998;Tibbetts et al, 2011a). Nevertheless, different results in the in vitro digestion have been found depending on the enzyme origin, suggesting a species-specific feature of in vitro protein digestion (Ezquerra et al, 1998;Lemos and Nunes, 2008;Moyano and Savoie, 2001).…”

Digestão in vitro de proteína e fósforo utilizando enzimas digestivas espécie-específicas: potencial de desenvolvimento e aplicação para a aquicultura de espécies de peixes

“…Apart from correlation and method validation, the pH-stat in vitro DH technique may be important to qualify or distinguish raw materials, indicating how much it could be potentially hydrolyzed in the fish digestive tract and, to a certain extent, the availability for absorption. The complex nature of food digestion in the live fish may not be easily replicated and it may also not be strictly required for consistent screening of feed protein quality, as demonstrated for farmed land and aquatic species (BASSOMPIERRE et al, 1997b;EGGUM, 1991;FERNÁNDEZ, 1995;DIMES et al, 1994a,b;HARDY, 2000;EZQUERRA et al, 1997;BARROWS, 2002;EGGUM, 1983;SHIPTON;BRITZ, 2002;TIBBETTS et al, 2011b). The DH has emerged with potential as accessory method in quality control of raw materials in the aqua feed manufacturing industry (DE MUYLDER et al, 2008;.…”

“…This motivated the development of in vitro methods based on the digestion of small amounts of feedstuff samples. Reported in vitro protein digestion methods include the use of digestive enzymes that may be available from commercial sources (LAZO et al, 1998;SHIPTON;BRITZ, 2002;TONHEIM et al, 2007) or recovered from the target species (ALARCÓN et al, 2002;HAARD, 1994;EZQUERRA et al, 1998;TIBBETTS et al, 2011a). Nevertheless, different results in the in vitro digestion have been found depending on the enzyme origin, suggesting a speciesspecific feature of in vitro protein digestion (ALARCÓN et al, 2002;EZQUERRA et al, 1998;LEMOS et al, 2004;NUNES, 2008;SAVOIE, 2001).…”

“…For aquatic animals, the focus has been on protein hydrolysis, as this nutrient may be more relevant in the metabolism and requirement than carbohydrates and lipids. The in vitro methods may include open or closed vessels, measure different products, e.g., released amino acids, degree of peptide bond hydrolysis, use commercially available enzyme sources or from the target species (ALARCÓN et al, 2002;BASSOMPIERRE, et al, 1997a;HAARD 1994;EZQUERRA et al, 1998;HAMDAN, et al, 2009;LAZO et al, 1998;MOYANO, 2010;SHIPTON;BRITZ, 2002;TIBBETTS et al, 2011a;TONHEIM et al, 2007). Substrate and enzymes may be incubated in aqueous solution under controlled conditions and final products measured after a given time (BASSOMPIERRE et al, 1998;DIVAKARAN et al, 2004;LAN;PAN, 1993); membrane reactors in which an inner reaction chamber is separated from the outer chamber by a dialysis membrane of variable molecular weight cut off (1000 -3500 Da) through which passes amino acids released during hydrolysis and are continuously removed from the outer chamber and quantified (HAMDAN et al, 2009;SAVOIE, 2001;MOYANO, 2010;GAUTHIER, 1986); substrate and enzymes may be incubated in aqueous solution under controlled conditions and the course of protein hydrolysis be evaluated by changes in pH, either by recording the change in pH (pH-drop or pH-shift) (LAZO et al, 1998) or by keeping the pH constant with continuous addition of titrant and measuring consumption (pH-stat) (CÓRDOVA-MURUETA; GARCÍA- CARREÑO, 2002;DIMES et al, 1994a;EL-MOWAFI et al, 2000;EZQUERRA et al, 1998;LEMOS et al, 2009;YASUMARU, 2010;TIBBETTS et al, 2011b).…”