Woyengo, T. A. and Nyachoti, C. M. 2013. Review: Anti-nutritional effects of phytic acid in diets for pigs and poultry Á current knowledge and directions for future research. Can. J. Anim. Sci. 93: 9Á21. Plant feedstuffs contain phytic acid (PA), which is a storage form of phosphorus. Phytic acid is, however, poorly hydrolyzed by pigs and poultry, and it has a capacity to complex dietary nutrients, thereby reducing nutrient digestibility. Reduced nutrient digestibility by PA implies reduced efficiency of utilization of the nutrients and increased discharge of the unabsorbed nutrients to the environment. Phytic acid has also recently been shown to increase the endogenous nutrient losses (ENL) in pigs and poultry. Because the increased ENL in the gastrointestinal tract are associated with increased maintenance requirement for the lost nutrients and of energy spent on their secretion, an increase in ENL due to PA implies that there are other adverse effects of PA on nutrient utilization in addition to reducing nutrient digestibility. In this review, the effects of PA on performance of pigs and poultry, and on the digestibility and ENL in these animals are discussed in detail. Also, the mechanisms by which PA reduces nutrient digestibility and increases gastrointestinal ENL in pigs and poultry are discussed, and areas that need further research to gain more insight into these mechanisms are suggested.Key words: Phytic acid, pig, poultry, nutrient utilization Woyengo, T. A. et Nyachoti, C. M. 2013. Effets anti-nutritionnels de l'acide phytique dans la ration des porcs et de la volaille Á connaissances actuelles et pistes pour les recherches a`venir. Can. J. Anim. Sci. 93: 9Á21. Les aliments ve´ge´taux renferment de l'acide phytique (AP), compose´servant a`stocker le phosphore. Malheureusement, les porcs et la volaille hydrolysent mal cet acide, qui, de plus, a tendance a`rendre les nutriments plus complexes, donc a`en re´duire la digestibilite´. Une digestibilite´plus faible des e´le´ments nutritifs suppose en retour une assimilation moins efficace et l'expulsion dans l'environnement d'une plus grande quantite´de nutriments non absorbe´s. Re´cemment, on a aussi montre´que l'AP augmente les pertes endoge`nes de nutriments (PEN) chez le porc et la volaille. L'augmentation des PEN dans le tube digestif est associe´e aux besoins de maintenance plus e´leve´s ne´cessaires pour compenser les nutriments perdus et l'e´nergie de´pense´e lors de leur se´cre´tion. La hausse des PEN attribuable a`l'AP laisse pre´sumer que celui-ci a d'autres effets secondaires sur l'assimilation des nutriments qu'une digestibilite´re´duite. L'analyse examine en de´tail les conse´quences de l'AP sur le rendement des porcs et de la volaille et sur la digestibilite´ainsi que les PEN chez ces animaux. On y discute aussi des me´canismes par lesquels l'AP re´duit la digestibilite´des nutriments et augmente les PEN dans le tube digestif des porcs et de la volaille. Les auteurs pre´conisent qu'on approfondissent les recherches dans ces domaines afin d'en...

Kahindi, R. K., Htoo, J. K. and Nyachoti, C. M. 2014. Short Communication: Effect of dietary lysine content and sanitation conditions on performance of weaned pigs fed antibiotic-free diets. Can. J. Anim. Sci. 94: 115–118. One hundred and ninety-two piglets (7.2±0.50 kg body weight) were fed corn–wheat–soybean meal based-diets to determine dietary Lys requirement in a 2×4 factorial setting [two sanitation conditions (SC): clean and unclean, and four dietary lysine contents: 0.94, 1.09, 1.25 and 1.43%]. The average daily gain (ADG) and gain to feed ratio (G:F) linearly increased (P<0.05) with dietary lysine contents, but were lower (P<0.0001) under unclean sanitation conditions from day 0 to 7 but not from day 8 to 21. Overall, dietary lysine contents did not affect average daily feed intake (ADFI), but unclean sanitation conditions reduced (P<0.01) ADFI; however, ADG was increased by both dietary lysine contents and SC? (P<0.001), whereas only dietary lysine contents affected G:F.

Woyengo, T. A., Akinremi, O. O., Rossnagel, B. G. and Nyachoti, C. M. 2012. Performance and total tract nutrient digestibility of growing pigs fed hulless low phytate barley. Can. J. Anim. Sci. 92: 505–511. An experiment was conducted to determine the performance and nutrient digestibility of growing pigs fed hulless low phytate (HLP) barley without or with phytase for 28 d. Twenty-four growing pigs (average initial body weight=25.3 kg) were fed three diets in a completely randomised design. The diets included a regular-hulled barley-based diet, and a HLP barley-based diet without or with phytase at 500 phytase units kg−1. Pigs fed the HLP barley-based diet without phytase had greater (P<0.05) average daily gain (0.911 vs. 0.717 kg), and apparent total tract digestibility of dry matter, energy, P, Mg, and Na were higher (P<0.05) than the regular barley-based diet. Supplementation of phytase to the HLP barley-based diet resulted in improved (P<0.05) feed conversion efficiency (0.506 vs. 0.547 kg kg−1), and apparent total tract digestibility of N, P and K. In conclusion, pigs fed the HLP barley-based diet had higher growth performance and nutrient digestibility than those fed the regular-hulled barley-based diet, indicating that the HLP barley is a better source of nutrients for pigs than regular barley. Phytase supplementation to the HLP barley-based diet can result in a further increase in nutrient utilisation by pigs.