A total of 640 male Ross 308 broiler chickens were used to explore the interactive effects of diet nutrient density, exogenous protease and ascorbic acid on performance, nutrient digestibility and various gut health metrics. A total of eight dietary treatments were arranged as a 2 × 2 × 2 factorial with the factors being adequate or reduced (~4%) crude protein and amino acids, without or with exogenous protease and without or with supplemental ascorbic acid. Over the 35-day experimental period, birds that received the adequate diet had higher (P < 0.01) bodyweight gain and lower (P < 0.001) feed conversion ratio (FCR) than birds that received the diet with reduced protein and amino acid density. Supplemental protease reduced (P < 0.001) FCR and this influence was more apparent in birds fed the diet with reduced protein concentration. Gut tensile strength tended to be increased by protease (P = 0.09) and ascorbic acid (P = 0.06) supplementation. Supplemental protease reduced (P < 0.001) jejunal goblet cell numbers and epithelial thickness and increased (P < 0.05) villus height compared with unsupplemented diets. Ascorbic acid tended (P = 0.05) to increase sialic acid concentration in ileal digesta. Protease increased (P < 0.01) the coefficients of apparent ileal digestibility for all amino acids other than methionine and this effect tended (P = 0.07 to 0.09) to be more pronounced in the low protein diet for aspartic acid, histidine and arginine. The concentration of taurine in ileal digesta was reduced (P < 0.01) by protease whereas hydroxyproline concentrations tended (P = 0.09) to increase by ascorbic acid addition. These results confirm previous reports on the effectiveness of exogenous protease in diets reduced in crude protein and digestible amino acids. Furthermore, both protease and ascorbic acid may influence gut health through promotion of tensile strength, epithelial morphology and endogenous protein flow. The interaction between exogenous protease and ascorbic acid on gut health with an emphasis on collagen structure and tight junction integrity is an area for future study.

The statement 'phytic acid is ubiquitously present in non-ruminant animal diets' is often made in scientific manuscripts oriented toward phytase, mineral and amino acid nutrition, monogastric animal performance and skeletal development. However, it is increasingly the case that this statement is at best misleading and at worst entirely incorrect. Phytase bio-efficacy is at an unprecedented high in the life cycle of this technology and product cost is at an all-time low, two factors which have contributed to a climb in inclusion concentration and an axiomatic decrease in dietary phytic acid concentration. Though complete dephytinisation of monogastric animal diets may be unrealistic due to the presence of variable concentrations of recalcitrant phytic acid in localized regions of cereals, oilseed meals and grain legumes, the vast majority of reactive phytic acid is rapidly degraded to innocuous lower esters in the proximal GI tract. Thus, the nutritional paradigm has shifted from formulating diets to accommodate the presence of phytase to formulating diets to accommodate the absence of phytic acid. These are not trivial distinctions but may have considerable implications for animal performance and the optimal balance of nutrients in the diet. It is the purpose of the present article to consider the breadth of effect of the ingestion of phytic acid and the likely consequence of an ostensibly dephytinized diet on nutrition and animal performance. The concept of 'phytate-free nutrition' is posited and nutritional strategies to maximise the likelihood of observing measurable benefits from the lack of this nutritional obstacle are discussed around three conceptual pillars: phosphorus, extra-phosphoric effects and myo-inositol. (C) 2016 The Authors. Published by Elsevier B.V.

A total of 1600 Ross broiler chicks were used in six separate balance studies (with equivalent protocols) to investigate the effect of an exogenous xylanase on the nutritional value of wheat (supplemented with a background of exogenous phytase) sourced from Asia, North America and Europe. The mean apparent metabolisable energy of the 10 batches of wheat per se was 13.4 MJ/kg DM and the addition of xylanase increased (P < 0.001) this by an average of 0.43 MJ/kg DM (~3.2%). Apparent ileal digestibility of nitrogen in the 10 batches of wheat per se was 69.8% and xylanase addition increased (P < 0.001) this by 2%. The apparent ileal disappearance of soluble and insoluble non-starch polysaccharides (NSP) was –53% and +5%, respectively and xylanase addition increased these by 28% and 15%, respectively. The apparent ileal disappearance of total arabinose + xylose was –10% and xylanase increased this by 21%. The apparent ileal flow of fucose was 0.38 g/kg DM intake and xylanase addition reduced (P < 0.05) this by 0.03 g/kg DM intake. There was a significant negative correlation between the apparent ileal flow of fucose and the digestibility of nitrogen and energy in the wheat and the wheat plus xylanase. These results demonstrate the continued effectiveness of exogenous xylanase to enhance the nutritional value of wheat for broiler chickens. Furthermore, the degradation of NSP fractions is confirmatory of both soluble and insoluble fibre hydrolysis in the intestine of the birds. Finally, although de-caging, viscosity amelioration and microbial changes are likely to be involved, the reduced flow of fucose in the intestine of birds fed wheat with supplemental xylanase is indicative of reduced endogenous (mucin) loss with net energy and enteric health implications. The effect of wheat pentosans and xylanase on intestinal secretion and endogenous protein and energy loss is an area for future study. Finally, the results presented herein suggest a reduction in soluble NSP concentrations in wheat over the past 2–3 decades, which is a trend that may explain anecdotal observations that the incidence of so-called sticky wheats is in decline. Systematic assessment of the implications of changing substrate concentrations and characteristics for new xylanase development is warranted.

Supplementation of crystalline amino acids is common in diets for piglets. The purpose of the present experiment was to conduct a study on an alternative amino acid provision by means of feeding piglets spores of a B. subtilis strain known to overproduce Val when cultured in vitro. Seventeen individually penned piglets per treatment were used. One week after weaning, piglets were fed one of 3 diets: a Val deficient (Val:Lys, 0.63:1; Neg), the same diet with added 1.28×106cfu B. subtilis/g feed (+Bac), or a diet containing Val at requirement levels for piglets (Val:Lys, 0.69:1; +Val). During the 26-d feeding period, Val deficiency reduced (P<0.001) feed intake and growth rate of piglets, and supplementation of B. subtilis spores was not effective enough to compensate for the Val deficiency. Although there were some effects on mucosa, the dietary treatments did not have major effects on amino acid concentrations in digesta and mucosa of the small intestine. However, the Val concentration in plasma of the portal and jugular veins and the urea concentration in plasma of the jugular vein were higher when piglets were fed the +Val diet. The Val:Lys of 0.63:1 was clearly below the requirement of Val for piglets. The dietary supplementation of the B. subtilis strain that can overproduce Val, did not provide Val in levels high enough to compensate for a Val deficiency. Further investigations should focus on optimizing strains to greater Val overproduction in the gastrointestinal tract of pigs and establishing the optimal dose of B. subtilis supplementation.

Salmonella continues to be a major public health burden worldwide. Poultry are known to be one of the main reservoirs for this zoonotic pathogen. It has previously been shown that a single dose of Bacillus subtilis reduces fecal shedding of Salmonella enterica serovar Enteritidis, whereas no effect on long-term colonization of the cecum has been observed. Here we report experiments that were undertaken to test the efficacy of a conventional diet supplemented with a probiotic (B. subtilis DSM17299) on 1) Salmonella colonization in the intestinal tract of broiler chickens, and 2) fecal shedding of Salmonella under production-like conditions. The trial birds fed the B. subtilis diet showed a significant 58% reduction in Salmonella-positive drag swabs compared with control birds, which had 100% presence of Salmonella. Feeding B. subtilis significantly reduced the average Salmonella load of cecum samples of the chickens, by 3 log units. This reduction in Salmonella colonization might not only positively affect broilers on the live production side by reducing the risk of infection between birds, but could also aid on the processing side by decreasing the amount of Salmonella entering the facility and improving food safety. Furthermore, numerical, but not statistically significant, improvements in feed conversion rate and BW gain at d 42 were observed in the B. subtilis-treated group compared with control birds.

Three studies were conducted using Clostridium perfringens as an intestinal challenge to produce necrotic enteritis (NE). The studies consisted of two battery screening studies and one production study in floor pens, which were used to test the effect of the addition of Bacillus licheniformis (DSM 17236) spores at different doses and feeding periods in comparison to birds fed diets with subtherapeutic levels of virginiamycin (15 g/ton feed). In all three studies the use of B. licheniformis (1.6 x 10(6) - 8 x 10(7) CFUs/g) or virginiamycin (15 g/ton feed) showed no difference in effect with regard to feed conversion ratio, weight gain, NE lesion score, and NE mortality. In the two battery studies, both treatments showed a significantly decreased feed conversion ratio, increased weight gain, reduced NE lesion score, and NE-reduced mortality compared to the nonmedicated C. perfringens-challenged group. In general, none of the treatments performed as well as the no-challenge group. The present data indicate that the use of B. licheniformis spores as a probiotic or direct-fed microbial could be an alternative to adding medication to the feed to overcome NE under commercial-like conditions and could therefore be of direct use in preventing antibiotic-resistant pathogens in chickens.